WorldWideScience

Sample records for optical transmission

  1. Ultrahigh Transmission Optical Nanofibers

    CERN Document Server

    Hoffman, J E; Grover, J A; Solano, P; Kordell, P R; Wong-Campos, J D; Orozco, L A; Rolston, S L

    2014-01-01

    We present a procedure for reproducibly fabricating ultrahigh transmission optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode transmissions of 99.95 $ \\pm$ 0.02%, which represents a loss from tapering of 2.6 $\\,\\times \\,$ 10$^{-5}$ dB/mm when normalized to the entire stretch. When controllably launching the next family of higher-order modes on a fiber with 195 mm stretch, we achieve a transmission of 97.8 $\\pm$ 2.8%, which has a loss from tapering of 5.0 $\\,\\times \\,$ 10$^{-4}$ dB/mm when normalized to the entire stretch. Our pulling and transfer procedures allow us to fabricate optical nanofibers that transmit more than 400 mW in high vacuum conditions. These results, published as parameters in our previous work, present an improvement of two orders of magnitude less loss for the fundamental mode and an increase in transmission of more than 300% for higher-order modes, when following the protocols detailed in this paper. We extract from the transmission during the pull, the only reported...

  2. Technology of optical azimuth transmission

    Science.gov (United States)

    Lu, Honggang; Hu, Chunsheng; Wang, Xingshu; Gao, Yang

    2012-11-01

    It often needs transfer a reference from one place to another place in aerospace and guided missile launching. At first, principles of several typical optical azimuth transmission methods are presented. Several typical methods are introduced, such as Theodolite (including gyro-theodolite) collimation method, Camera series method, Optical apparatus for azimuth method and polarization modulated light transmission method. For these typical azimuth transmission methods, their essential theories are elaborated. Then the devices, the application fields and limitations of these typical methods' are presented. Theodolite (including gyro-theodolite) collimation method is used in the ground assembly of spacecraft. Camera series method and optical apparatus for azimuth method are used in azimuth transmission between different decks of ship. Polarization modulated light transmission method is used in azimuth transmission of rocket and guided missile. At the last, the further developments of these methods are discussed.

  3. Ultrahigh-Speed Optical Transmission Technology

    CERN Document Server

    Weber, Hans-Georg

    2007-01-01

    Ultrahigh-speed optical transmission technology is a key technology for increasing the communication capacity. In optical fibre networks, the number of wavelength channels and the bit rate per wavelength channel, i.e. the TDM (Time Division Multiplexing) bit rate, determine the transmission capacity. Currently, TDM bit rates of more than 40 Gbit/s require optical signal processing (Optical Time Division Multiplexing, OTDM). OTDM bit rates of up to 1.2 Tbit/s have already been reported. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.

  4. Optoelectronic line transmission an introduction to fibre optics

    CERN Document Server

    Tricker, Raymond L

    2013-01-01

    Optoelectronic Line Transmission: An Introduction to Fibre Optics presents a basic introduction as well as a background reference manual on fiber optic transmission. The book discusses the basic principles of optical line transmission; the advantages and disadvantages of optical fibers and optoelectronic signalling; the practical applications of optoelectronics; and the future of optoelectronics. The text also describes the theories of optical line transmission; fibers and cables for optical transmission; transmitters including light-emitting diodes and lasers; and receivers including photodi

  5. Enhanced broadband optical transmission in metallized woodpiles

    DEFF Research Database (Denmark)

    Malureanu, Radu; Alabastri, A.; Cheng, W.;

    2011-01-01

    We present an optimized isotropic metal deposition technique used for covering three-dimensional polymer structures with a 50 nm smooth silver layer. The technology allows fast and isotropic coating of complex 3D dielectric structures with thin silver layers. Transmission measurements of 3D...... metallized woodpiles reveal a new phenomenon of enhanced optical transmission in broadband range (up to 300 nm) in the near IR....

  6. Spectrally efficient polymer optical fiber transmission

    Science.gov (United States)

    Randel, Sebastian; Bunge, Christian-Alexander

    2011-01-01

    The step-index polymer optical fiber (SI-POF) is an attractive transmission medium for high speed communication links in automotive infotainment networks, in industrial automation, and in home networks. Growing demands for quality of service, e.g., for IPTV distribution in homes and for Ethernet based industrial control networks will necessitate Gigabit speeds in the near future. We present an overview on recent advances in the design of spectrally efficient and robust Gigabit-over-SI-POF transmission systems.

  7. Economics Of Optical Fibre Transmission Systems

    Science.gov (United States)

    Murray, W. J.

    1983-08-01

    Optical fibre as a telecommunication transmission medium has become one of the most significant developments so far of the digital era. A major contributory factor to the availability of optical fibre transmission systems has been the outstanding progress in the technology of manufacturing high quality glass fibre having relatively low attenuation and broad bandwidths. This and other achievements has enabled manufacturers in the United Kingdom to develop a range of optical fibre cables and transmission equipment for operation over short and long distances at the CCITT recommended digital hierarchical rates of 2, 8, 34 and 140Mbit/s which have been adopted by British Telecom (BT) for modernisation to an all digital transmission network. These optical fibre systems are now becoming increasingly price and performance competitive with conventional technology in many parts of telecommunications networks. In the British Telecom (BT) network the 140Mbit/s optical fibre systems are now economically competitive with equivalent systems on coaxial cable and microwave radio. The economics of 8 and 34Mbit/s systems are not yet sufficiently attractive, compared with 2Mbit/s digital line systems on pair type copper cables, for large scale use in rural and local distribution networks and are presently only justified on cost in and around large cities. As system costs decrease large applications are predicted particularly in support of future high speed data, cable television and visual information services.

  8. All optical OFDM transmission for passive optical networks

    Science.gov (United States)

    Kachare, Nitin; Ashik T., J.; Bai, K. Kalyani; Kumar, D. Sriram

    2017-06-01

    This paper demonstrates the idea of data transmission at a very higher rate (Tbits/s) through optical fibers in a passive optical network using the most efficient data transmission technique widely used in wireless communication that is orthogonal frequency division multiplexing. With an increase in internet users, data traffic has also increased significantly and the current dense wavelength division multiplexing (DWDM) systems may not support the next generation passive optical networks (PONs) requirements. The approach discussed in this paper allows to increase the downstream data rate per user and extend the standard single-mode fiber reach for future long-haul applications. All-optical OFDM is a promising solution for terabit per second capable single wavelength transmission, with high spectral efficiency and high tolerance to chromatic dispersion.

  9. The Soliton Transmissions in Optical Fibers

    Directory of Open Access Journals (Sweden)

    Leos Bohac

    2010-01-01

    Full Text Available The objective of this paper is to familiarize readers with the basic analytical propagation model of short optical pulses in optical fiber. Based on this model simulation of propagation of the special type of pulse, called a soliton, will be carried out. A soliton transmission is especially attractive in the fiber optic telecommunication systems as it does not change a pulses shape during propagating right-down the fiber link to the receiver. The model of very short pulse propagation is based on the numerical solution of the nonlinear Schroedinger equation (NLSE, although in some specific cases it is possible to solve it analytically.

  10. Measuring optical transmission matrices by wavefront shaping

    CERN Document Server

    Yoon, Jonghee; Park, Jongchan; Park, YongKeun

    2015-01-01

    We introduce a simple but practical method to measure the optical transmission matrix (TM) of complex media. The optical TM of a complex medium is obtained by modulating the wavefront of a beam impinging on the complex medium and imaging the transmitted full-field speckle intensity patterns. Using the retrieved TM, we demonstrate the generation and linear combination of multiple foci on demand through the complex medium. This method will be used as a versatile tool for coherence control of waves through turbid media.

  11. Optical Transmission Properties of Dielectric Aperture Arrays

    Science.gov (United States)

    Yang, Tao

    Optical detection devices such as optical biosensors and optical spectrometers are widely used in many applications for the functions of measurements, inspections and analysis. Due to the large dimension of prisms and gratings, the traditional optical devices normally occupy a large space with complicated components. Since cheaper and smaller optical devices are always in demand, miniaturization has been kept going for years. Thanks to recent fabrication advances, nanophotonic devices such as semiconductor laser chips have been growing in number and diversity. However, the optical biosensor chips and the optical spectrometer chips are seldom reported in the literature. For the reason of improving system integration, the study of ultra-compact, low-cost, high-performance and easy-alignment optical biosensors and optical spectrometers are imperative. This thesis is an endeavor in these two subjects and will present our research work on studying the optical transmission properties of dielectric aperture arrays and developing new optical biosensors and optical spectrometers. The first half of the thesis demonstrates that the optical phase shift associated with the surface plasmon (SP) assisted extraordinary optical transmission (EOT) in nano-hole arrays fabricated in a metal film has a strong dependence on the material refractive index value in close proximity to the holes. A novel refractive index sensor based on detecting the EOT phase shift is proposed by building a model. This device readily provides a 2-D biosensor array platform for non-labeled real-time detection of a variety of organic and biological molecules in a sensor chip format, which leads to a high packing density, minimal analyte volumes, and a large number of parallel channels while facilitating high resolution imaging and supporting a large space-bandwidth product (SBP). Simulation (FDTD Solutions, Lumerical Solutions Inc) results indicate an achievable sensitivity limit of 4.37x10-9 refractive index

  12. Energy efficiency of optical grooming of QAM optical transmission channels.

    Science.gov (United States)

    Bhopalwala, Mariya; Rastegarfar, Houman; Kilper, Daniel C; Wang, Michael; Bergman, Keren

    2016-02-01

    Analysis of the energy use for optical grooming of quadrature amplitude modulated signals in optical transmission systems is used to determine the potential efficiency benefits. An energy model is developed for both optical and electronic grooming and used to study the relative efficiency for three different network scenarios. The energy efficiency is evaluated considering both coherent and direct detection transceivers including power management strategies. Results indicate efficiency improvements up to an order of magnitude may be possible for 100 GBaud rates and 25-30 GBaud is a critical point at which optical grooming becomes the more efficient approach. These results are further shown to apply for the case of projected efficiency improvements in the underlying device technologies.

  13. Optical scanning cryptography for secure wireless transmission

    Science.gov (United States)

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-01

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

  14. Optical scanning cryptography for secure wireless transmission.

    Science.gov (United States)

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-10

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

  15. Measurement of magnetic moment via optical transmission

    Energy Technology Data Exchange (ETDEWEB)

    Heidsieck, Alexandra, E-mail: aheidsieck@tum.de; Schmid, Daniel; Gleich, Bernhard

    2016-03-01

    The magnetic moment of nanoparticles is an important property for drug targeting and related applications as well as for the simulation thereof. However, the measurement of the magnetic moment of nanoparticles, nanoparticle–virus-complexes or microspheres in solution can be difficult and often yields unsatisfying or incomparable results. To measure the magnetic moment, we designed a custom measurement device including a magnetic set-up to observe nanoparticles indirectly via light transmission in solution. We present a simple, cheap device of manageable size, which can be used in any laboratory as well as a novel evaluation method to determine the magnetic moment of nanoparticles via the change of the optical density of the particle suspension in a well-defined magnetic gradient field. In contrast to many of the established measurement methods, we are able to observe and measure the nanoparticle complexes in their natural state in the respective medium. The nanoparticles move along the magnetic gradient and thereby away from the observation point. Due to this movement, the optical density of the fluid decreases and the transmission increases over time at the measurement location. By comparing the measurement with parametric simulations, we can deduce the magnetic moment from the observed behavior. - Highlights: • Performance of a direct detection camera in the context of off-axis electron holography has been evaluated. • A measurement device to indirectly observe magnetic nanoparticles (MNPs) is described. • MNPs can be observed in the respective medium via light transmission. • An evaluation method to determine the magnetic moment of the MNPs is presented. • The magnetic moment can be deduced from the observed change in optical density.

  16. Nonlinear optical properties of induced transmission filters.

    Science.gov (United States)

    Owens, Daniel T; Fuentes-Hernandez, Canek; Hales, Joel M; Perry, Joseph W; Kippelen, Bernard

    2010-08-30

    The nonlinear optical (NLO) properties of induced transmission filters (ITFs) based on Ag are experimentally determined using white light continuum pump-probe measurements. The experimental results are supported using simulations based on the matrix transfer method. The magnitude of the NLO response is shown to be 30 times that of an isolated Ag film of comparable thickness. The impacts of design variations on the linear and NLO response are simulated. It is shown that the design can be modified to enhance the NLO response of an ITF by a factor of 2 or more over a perfectly matched ITF structure.

  17. Transmissive Diffractive Optical Element Solar Concentrators

    Science.gov (United States)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

    Solar-thermal-radiation concentrators in the form of transmissive diffractive optical elements (DOEs) have been proposed as alternatives to mirror-type solar concentrators now in use. In comparison with functionally equivalent mirror-type solar concentrators, the transmissive, diffractive solar concentrators would weigh and cost less, and would be subject to relaxed mechanical tolerances. A DOE concentrator would be made from a thin, flat disk or membrane of a transmissive material having a suitable index of refraction. By virtue of its thinness, the DOE concentrator would have an areal mass density significantly less than that of a functionally equivalent conventional mirror. The DOE concentrator would have a relatively wide aperture--characterized by a focal-length/aperture-diameter ratio ('f number') on the order of 1. A kinoform (a surface-relief phase hologram) of high diffractive order would be microfabricated onto one face of the disk. The kinoform (see figure) would be designed to both diffract and refract incident solar radiation onto a desired focal region, without concern for forming an image of the Sun. The high diffractive order of this kinoform (in contradistinction to the low diffractive orders of some other kinoforms) would be necessary to obtain the desired f number of 1, which, in turn, would be necessary for obtaining a desired concentration ratio of 2,500 or greater. The design process of optimizing the concentration ratio of a proposed DOE solar concentrator includes computing convolutions of the optical bandwidth of the Sun with the optical transmission of the diffractive medium. Because, as in the cases of other non-imaging, light-concentrating optics, image quality is not a design requirement, the process also includes trading image quality against concentration ratio. A baseline design for one example calls for an aperture diameter of 1 m. This baseline design would be scalable to a diameter as large as 10 m, or to a smaller diameter for a

  18. Extraordinary transmission in optical Helmholtz resonators.

    Science.gov (United States)

    Chevalier, Paul; Bouchon, Patrick; Sakat, Emilie; Pelouard, Jean-Luc; Pardo, Fabrice; Haïdar, Riad

    2015-06-15

    Optical Helmholtz resonators (OHRs) have been adapted from acoustics designs for light absorbing structures, exhibiting extreme light confinement. Here, extraordinary transmission of light is theoretically demonstrated through symmetric OHRs, comprising a cavity with two λ/500 narrow slits on either side. This device has appealing features to act as a spectral bandpass filter in the context of multispectral imaging, in particular its high angular tolerance because of the localized nature of the resonance. Besides, the cavity can be modeled as an inductor and the two slits can be modeled as capacitors, the whole design acting as a LC circuit thus preventing any harmonic features.

  19. Optical data transmission at the superconducting super collider

    Energy Technology Data Exchange (ETDEWEB)

    Leskovar, B. [Lawrence Berkeley Lab., CA (United States)

    1989-04-01

    Digital and analog data transmissions via fiber optics for the Superconducting Super Collider have been investigated. The state of the art of optical transmitters, low loss fiber waveguides, receivers and associated electronics components are reviewed and summarized. Emphasis is placed on the effects of the radiation environment on the performance of an optical data transmission system components. Also, the performance of candidate components of the wide band digital and analog transmission systems intended for deployment in the Superconducting Super Collider Detector is discussed.

  20. Optical Curtain Effect: Extraordinary Optical Transmission Enhanced by Antireflection

    CERN Document Server

    Cui, Yanxia; Lin, Yinyue; Li, Guohui; Hao, Yuying; He, Sailing; Fang, Nicholas X

    2012-01-01

    In this paper, we employ an antireflective coating which comprises of inverted pi shaped metallic grooves to manipulate the behaviour of a TM-polarized plane wave transmitted through a periodic nanoslit array. At normal incidence, such scheme can not only retain the optical curtain effect in the output region, but also generate the extraordinary transmission of light through the nanoslits with the total transmission efficiency as high as 90%. Besides, we show that the spatially invariant field distribution in the output region as well as the field distribution of resonant modes around the inverted pi shaped grooves can be reproduced immaculately when the system is excited by an array of point sources beneath the inverted pi shaped grooves. In further, we investigate the influence of center-groove and side-corners of the inverted pi shaped grooves on suppressing the reflection of light, respectively. Based on our work, it shows promising potential in applications of enhancing the extraction efficiency as well ...

  1. Power Transmission by Optical Fibers for Component Inherent Communication

    Directory of Open Access Journals (Sweden)

    Michael Dumke

    2010-02-01

    Full Text Available The use of optical fibers for power transmission has been investigated intensely. An optically powered device combined with optical data transfer offers several advantages compared to systems using electrical connections. Optical transmission systems consist of a light source, a transmission medium and a light receiver. The overall system performance depends on the efficiency of opto-electronic converter devices, temperature and illumination dependent losses, attenuation of the transmission medium and coupling between transmitter and fiber. This paper will summarize the state of the art for optically powered systems and will discuss reasons for negative influences on efficiency. Furthermore, an outlook on power transmission by the use of a new technology for creating polymer optical fibers (POF via micro dispensing will be given. This technology is capable to decrease coupling losses by direct contacting of opto-electronic devices.

  2. 100-Gbps hybrid optical fiber-wireless transmission

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Caballero Jambrina, Antonio; Deng, Lei;

    2013-01-01

    We present experimental results on using optical transmission technologies such as I&Q modulators, digital coherent receivers, heterodyne up-conversion in fast photodiodes, to generate, transmit and detect high capacity wireless transmission. Both OFDM and QAM modulation formats are tested in the......-achieving capacities up to 100-Gbps with seamless optical fiber-wireless conversion.......We present experimental results on using optical transmission technologies such as I&Q modulators, digital coherent receivers, heterodyne up-conversion in fast photodiodes, to generate, transmit and detect high capacity wireless transmission. Both OFDM and QAM modulation formats are tested in the W...

  3. Algorithm for predictive control implementation on fiber optic transmission lines

    Science.gov (United States)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Voronkov, Andrey A.

    2014-04-01

    This paper presents the algorithm for predictive control implementation on fiber-optic transmission lines. In order to improve the maintenance of fiber optic communication lines, the algorithm prediction uptime optic communication cables have been worked out. It considers the results of scheduled preventive maintenance and database of various works on the track cable line during maintenance.

  4. Different Types of Coding Input Data In Optical Transmission Systems

    Directory of Open Access Journals (Sweden)

    Ján Ružbarský

    2016-12-01

    Full Text Available Optical fiber transmission systems are currently the most widely used transmission media. Their development in time had improved their characteristics to such an extent that they gradually replaced very popular copper cable connections. Inspite of that optical fibers still have not reached perfection and constant improvement is needed. Apart from notable advantages such as large data transfer, few numbers of repeaters required on the transmission path or higher safety of transmitted data, optical fiber has also drawbacks that include not sufficient purity optical fibers, fiber fragility and also higher proclivity to nonlinear effects. Weaknesses of optical systems can be depressed by e.g. a selection of an appropriate laser, a proper combination of materials used for fiber production during the manufacture process, or even by using an encryption of transmitted data. This article is focused on the comparison of optical signal properties in various source encoding types of input data.

  5. Digital processing optical transmission and coherent receiving techniques

    CERN Document Server

    Binh, Le Nguyen

    2013-01-01

    With coherent mixing in the optical domain and processing in the digital domain, advanced receiving techniques employing ultra-high speed sampling rates have progressed tremendously over the last few years. These advances have brought coherent reception systems for lightwave-carried information to the next stage, resulting in ultra-high capacity global internetworking. Digital Processing: Optical Transmission and Coherent Receiving Techniques describes modern coherent receiving techniques for optical transmission and aspects of modern digital optical communications in the most basic lines. The

  6. Installation of optical shieldwire on existing transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Trausch, S. (Fluor Daniel, Chicago, IL (US))

    1988-01-01

    The author reports the development of a communication network between Minneapolis and Chicago. The fiber optics cable was installed, with a few exceptions, on existing transmission lines. Most of the utilized transmission structures are 138-161 kV wood pole H-frame structures with two shield wires. One of the shield wires was removed and replaced by the fiber optic cable. In a 30-mile section the fiber optic cable was installed on 345 kV lines supported on steel poles and steel lattice towers. Generally, however, 345 kV lines were avoided because it was difficult to obtain outages for the installation of the optic ground wire (OPGW). In some cases, where existing transmission line structures could not be used, the fiber optic cable was installed on 30- to 50-foot single wood pole structures designed to support this cable.

  7. Transmission of straight and curved multimode optical fibers

    Science.gov (United States)

    Melnik, Ivan S.; Kravchenko, Igor; Denisov, Nikolay A.; Dets, Sergiy M.; Rusina, Tatyana V.

    1995-01-01

    Bent multimode optical fibers were studied using a 3D ray tracing program. Effect of fiber bending increased with smaller input aperture beams. Transmission of fibers decreased for the longer proximal straight part of the fiber. Significant focusing effect and output light redistribution were detected if a proximal straight part of the fiber was less than 1 fiber diameter. Transmission of hollow waveguides considerably depended on the inner surface quality. Calculated data were in accordance with experimental measurements of fiber transmission and output light distribution. Ray tracing is a useful approach to simulate different delivery systems using optical fibers and hollow waveguides.

  8. Wideband optical transmission properties of seven thermoplastics.

    Science.gov (United States)

    Lytle, J D; Wilkerson, G W; Jaramillo, J G

    1979-06-01

    Transmission measurements were made on samples of acrylic, polystyrene, styrene-acrylic copolymer (N.A.S.), polymethyl pentene (TPX), polysulfone, polycarbonate, and Trogamid; molded windows of 5.08-mm thickness were measured over the range 0.4-40.0 microm. All these injection-moldable materials appear to be usable in the visible region, and have surprisingly similar transmission profiles from 1.0 microm to 2.0 microm. Polystyrene and TPX possess several potentially useful transmission windows in the middle-wavelength and long-wavelength infrared regions, particularly TPX. The potential of these materials as substitutes for expensive crystalline materials in infrared application is discussed. The possibility that other thermoplastic materials may offer similar opportunities is also presented.

  9. Optical signal monitoring in phase modulated optical fiber transmission systems

    Science.gov (United States)

    Zhao, Jian

    Optical performance monitoring (OPM) is one of the essential functions for future high speed optical networks. Among the parameters to be monitored, chromatic dispersion (CD) is especially important since it has a significant impact on overall system performance. In this thesis effective CD monitoring approaches for phase-shift keying (PSK) based optical transmission systems are investigated. A number of monitoring schemes based on radio frequency (RF) spectrum analysis and delay-tap sampling are proposed and their performance evaluated. A method for dispersion monitoring of differential phase-shift keying (DPSK) signals based on RF power detection is studied. The RF power spectrum is found to increase with the increase of CD and decrease with polarization mode dispersion (PMD). The spectral power density dependence on CD is studied theoretically and then verified through simulations and experiments. The monitoring sensitivity for nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) based systems can reach 80ps/nm/dB and 34ps/nm/dB respectively. The scheme enables the monitoring of differential group delay (DGD) and CD simultaneously. The monitoring sensitivity of CD and DGD can reach 56.7ps/nm/dB and 3.1ps/dB using a bandpass filter. The effects of optical signal-to-noise ratio (OSNR), DGD, fiber nonlinearity and chirp on the monitoring results are investigated. Two RF pilot tones are employed for CD monitoring of DPSK signals. Specially selected pilot tone frequencies enable good monitoring sensitivity with minimum influence on the received signals. The dynamic range exceeding 35dB and monitoring sensitivity up to 9.5ps/nm/dB are achieved. Asynchronous sampling technique is employed for CD monitoring. A signed CD monitoring method for 10Gb/s NRZ-DPSK and RZ-DPSK systems using asynchronous delay-tap sampling technique is studied. The demodulated signals suffer asymmetric waveform distortion if

  10. Enhanced broadband optical transmission in metallized woodpiles

    DEFF Research Database (Denmark)

    Malureanu, Radu; Alabastri, A.; Cheng, W.;

    2010-01-01

    We present an optimized isotropic metal deposition technique used for coating three-dimensional polymer structures with a 50nm smooth silver layer. The technology allows fast isotropic coating of complex 3D dielectric structures with thin silver layers. Transmission measurements of 3D metallized...

  11. 40 Gb/s optical transmission systems

    DEFF Research Database (Denmark)

    Buxens Azcoaga, Alvaro Juan; Nielsen, Steen Krogh

    2003-01-01

    application (maximum distance of 40 km) the maximum PMD coeficient allowed in the transmission fiber, 0.4 ps=pkm, is below the values defined by actual standards, 0.5 ps=pkm. The most promising PMD compensation methods are presented and their advantages and disadvantages are discussed. A PMD compensator based...

  12. Fiber optic transmissions in electrical utility applications

    Science.gov (United States)

    Lamarche, Louis

    2000-12-01

    The application of optic and photonic technology in electric networks in many cases is subject to constraints that differ from telecommunication or commercial applications. Starting by an overview of the quality of service (QoS) needed, in the first part of this paper we summarise some issues that confronted Hydro-Quebec in applying fibre optic technologies to its network. We explore by presenting lab and field trials some issues related to optical ground wires (OPGW) design and network architecture. We present temperature, vibration, ageing and short circuit current effects. We submit the results and analysis of a first field trial of and OC-48 link over a 265 km OPGW line, PMD measurements and an overview of the final design that is being implemented presently using Raman amplification. In the last section of the paper, we will discuss shortly of non-conventional photonic based technologies, local and distributed sensors and optical phenomenon that are used or have been discovered in utilities optical networks.

  13. Measuring Large Optical Transmission Matrices of Disordered Media

    Science.gov (United States)

    Choi, Wonshik; Lee, Ji Oon; Feld, Michael S.; Dasari, Ramachandra R.; Park, YongKeun

    2014-01-01

    We report a measurement of the large optical transmission matrix (TM) of a complex turbid medium. The TM is acquired using polarization-sensitive, full-field interferometric microscopy equipped with a rotating galvanometer mirror. It is represented with respect to input and output bases of optical modes, which correspond to plane wave components of the respective illumination and transmitted waves. The modes are sampled so finely in angular spectrum space that their number exceeds the total number of resolvable modes for the illuminated area of the sample. As such, we investigate the singular value spectrum of the TM in order to detect evidence of open transmission channels, predicted by random-matrix theory. Our results comport with theoretical expectations, given the experimental limitations of the system. We consider the impact of these limitations on the usefulness of transmission matrices in optical measurements. PMID:24160602

  14. Minimal model for optical transmission through holey metal films

    Energy Technology Data Exchange (ETDEWEB)

    MartIn-Moreno, L [Departamento de Fisica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); GarcIa-Vidal, F J [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: lmm@unizar.es

    2008-07-30

    This paper presents a tutorial on the computation of both extraordinary optical transmission and surface electromagnetic modes in holey metal films. Our model consists of a square array of square holes in a perfect conductor. It is shown that considering just the fundamental waveguide mode inside the holes captures the main features of the optical transmission, which allows us to obtain quasi-analytical results. Extraordinary optical transmission is unambiguously linked to the presence of surface electromagnetic modes in the corrugated structure. The particular case of surface electromagnetic modes in a perfect conductor is analyzed, paying attention to different strategies for increasing their confinement to the surface. The use of the energy loss of a charged particle passing close to the surface as a spectroscopic tool for these surface modes is also discussed.

  15. Measuring large optical transmission matrices of disordered media.

    Science.gov (United States)

    Yu, Hyeonseung; Hillman, Timothy R; Choi, Wonshik; Lee, Ji Oon; Feld, Michael S; Dasari, Ramachandra R; Park, YongKeun

    2013-10-11

    We report a measurement of the large optical transmission matrix (TM) of a complex turbid medium. The TM is acquired using polarization-sensitive, full-field interferometric microscopy equipped with a rotating galvanometer mirror. It is represented with respect to input and output bases of optical modes, which correspond to plane wave components of the respective illumination and transmitted waves. The modes are sampled so finely in angular spectrum space that their number exceeds the total number of resolvable modes for the illuminated area of the sample. As such, we investigate the singular value spectrum of the TM in order to detect evidence of open transmission channels, predicted by random-matrix theory. Our results comport with theoretical expectations, given the experimental limitations of the system. We consider the impact of these limitations on the usefulness of transmission matrices in optical measurements.

  16. Reflective Optical Limiter Based on Resonant Transmission

    CERN Document Server

    Makri, Eleana; Vitebskiy, Ilya

    2014-01-01

    Optical limiters transmit low-level radiation while blocking electromagnetic pulses with excessively high energy (energy limiters) or with excessively high peak intensity (power limiters). A typical optical limiter absorbs most of the high-level radiation which can cause its destruction via overheating. Here we introduce the novel concept of a reflective energy limiter which blocks electromagnetic pulses with excessively high total energy by reflecting them back to space, rather than absorbing them. The idea is to use a defect layer with temperature dependent loss tangent embedded in a low-loss photonic structure. The low energy pulses with central frequency close to that of the localized defect mode will pass through. But if the cumulative energy carried by the pulse exceeds certain level, the entire photonic structure reflects the incident light (and does not absorb it!) for a broad frequency window. The underlying physical mechanism is based on self-regulated impedance mismatch which increases dramatically...

  17. Metrology of transmission optics for LIGO

    Science.gov (United States)

    Walsh, Christopher J.; Leistner, Achim J.; Oreb, Bozenko F.; Seckold, Jeffrey A.; Farrant, David I.; Pavlovic, Edita

    1999-08-01

    CSIRO is manufacturing the `core' optical substrates for LIGO, a Michelson interferometer with arms up to 4 km in length each containing a Fabry Perot cavity. The beam splitter and input test mass mirrors (the entrance mirror to each cavity) have specifications not only for the optical surfaces but also for the radius of curvature of the wave front transmitted through the optical substrate. Our approach to manufacturing the substrates is to calculate the quadratic component of refractive index gradient (Delta) n from measurement of the transmitted wave front and the surface relief of the two substrate surfaces. After one of the surfaces (S1) is polished to specification, the radius on the second side required to achieve the specification on the transmitted wave front is calculated (using the measured value of (Delta) n, the actual value of S1 and the target value of the transmitted wave front). Results of this work and complications of the measurement procedure due to the thermal inertia and poor thermal conductivity of the silica substrates will be presented.

  18. Some Advances in the Circuit Modeling of Extraordinary Optical Transmission

    Directory of Open Access Journals (Sweden)

    F. Medina

    2009-06-01

    Full Text Available The phenomenon of extraordinary optical transmission (EOT through electrically small holes perforated on opaque metal screens has been a hot topic in the optics community for more than one decade. This experimentally observed frequency-selective enhanced transmission of electromagnetic power through holes, for which classical Bethe's theory predicts very poor transmission, later attracted the attention of engineers working on microwave engineering or applied electromagnetics. Extraordinary transmission was first linked to the plasma-like behavior of metals at optical frequencies. However, the primary role played by the periodicity of the distribution of holes was soon made evident, in such a way that extraordinary transmission was disconnected from the particular behavior of metals at optical frequencies. Indeed, the same phenomenon has been observed in the microwave and millimeter wave regime, for instance. Nowadays, the most commonly accepted theory explains EOT in terms of the interaction of the impinging plane wave with the surface plasmon-polariton-Bloch waves (SPP-Bloch supported by the periodically perforated plate. The authors of this paper have recently proposed an alternative model whose details will be briefly summarized here. A parametric study of the predictions of the model and some new potential extensions will be reported to provide additional insight.

  19. Radiative Thermo-Refractive Noise for Transmissive Optics

    CERN Document Server

    Dwyer, Sheila

    2014-01-01

    Radiative losses have traditionally been neglected in the calculation of thermal noise of transmissive optical elements because for the most commonly used geometries they are small compared to losses due to thermal conduction. We explore the use of such transmissive optical elements in extremely noise-sensitive environments such as the arm cavities of future gravitational-wave interferometers. This drives us to a geometry regime where radiative losses are no longer negligible. In this paper we derive the thermal noise associated with such radiative losses and compare it to other known sources of thermal noise.

  20. Subcarrier multiplexing tolerant dispersion transmission system employing optical broadband sources.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-16

    This paper presents a novel SCM optical transmission system for next-generation WDM-PONs combining broadband optical sources and a Mach-Zehnder interferometric structure. The approach leeds to transport RF signals up to 50 GHz being compatible with RoF systems since a second configuration has been proposed in order to overcome dispersion carrier suppression effect using DSB modulation. The theoretical analysis validates the potentiality of the system also considering the effects of the dispersion slope over the transmission window.

  1. Fiber-Optic Transmission Networks Efficient Design and Dynamic Operation

    CERN Document Server

    Pachnicke, Stephan

    2012-01-01

    Next generation optical communication systems will have to transport a significantly increased data volume at a reduced cost per transmitted bit. To achieve these ambitious goals optimum design is crucial in combination with dynamic adaptation to actual traffic demands and improved energy efficiency. In the first part of the book the author elaborates on the design of optical transmission systems. Several methods for efficient numerical simulation are presented ranging from meta-model based optimization to parallelization techniques for solving the nonlinear Schrödinger equation. Furthermore, fast analytical and semi-analytical models are described to estimate the various degradation effects occurring on the transmission line. In the second part of the book operational aspects of optical networks are investigated. Physical layer impairment-aware routing and regenerator placement are studied. Finally, it is analyzed how the energy efficiency of a multi-layer optical core network can be increased by dynamic ad...

  2. Inverse design of periodic metallic slits for extraordinary optical transmission

    CERN Document Server

    Deng, Yongbo; Liu, Zhenyu; Wu, Yihui

    2016-01-01

    The inverse design methodology of periodic metallic slits for extraordinary optical transmission is presented based on the topology optimization method. Several topological configurations of periodic metallic slits with typical subwavelength size are derived with transmission peaks at the prescribed incident wavelengths in the visible light region, where the transmissivity is enhanced by effective excitation of surface-plasmon-polariton at the inlet side of the slit, Fabry-P\\'erot resonance of surface-plasmon-polariton inside the slit and radiation of the electromagnetic energy at the outlet side of the slit. The transmission peaks of the derived metallic configurations are raised along with the red shift of the incident wavelength, because of the reduction of the energy absorption and increase of the propagation distance of surface-plasmon-polariton. And the shift of transmission peak is controlled by prescribing a different incident wavelength in the corresponding topology optimization problem. To reduce th...

  3. Photonic layer security in fiber-optic networks and optical OFDM transmission

    Science.gov (United States)

    Wang, Zhenxing

    Currently the Internet is experiencing an explosive growth in the world. Such growth leads to an increased data transmission rate demand in fiber-optical networks. Optical orthogonal frequency multiplexing (OFDM) is considered as a promising solution to achieve data rate beyond 100Gb/s per wavelength channel. In the meanwhile, because of extensive data transmission and sharing, data security has become an important problem and receives considerable attention in current research literature. This thesis focuses on data security issues at the physical layer of optical networks involving code-division multiple access (CDMA) systems and steganography methods. The thesis also covers several implementation issues in optical OFDM transmission. Optical CDMA is regarded as a good candidate to provide photonic layer security in multi-access channels. In this thesis we provide a systematic analysis of the security performance of incoherent optical CDMA codes. Based on the analysis, we proposed and experimentally demonstrated several methods to improve the security performance of the optical CDMA systems, such as applying all-optical encryption, and code hopping using nonlinear wavelength conversion. Moreover, we demonstrate that the use of wireless CDMA codes in optical systems can enhance the security in one single-user end-to-end optical channel. Optical steganography is another method to provide photonic data security and involves hiding the existence of data transmissions. In the thesis, we demonstrate that an optical steganography channel can exist in phase modulated public channels as well as traditional on-off-keying (OOK) modulated channels, without data synchronization. We also demonstrate an optical steganography system with enhanced security by utilizing temporal phase modulation techniques. Additionally, as one type of an overlay channel, the optical steganography technology can carry the sensor data collected by wireless sensor network on top of public optical

  4. Enhanced coherent OTDR for long span optical transmission lines containing optical fiber amplifiers

    Science.gov (United States)

    Furukawa, Shin-Ichi; Tanaka, Kuniaki; Koyamada, Yahei; Sumida, Masatoyo

    1995-05-01

    We have newly constructed an enhanced coherent optical time domain reflectometer (C-OTDR) for use in testing optical cable spans in transmission lines containing erbium-doped fiber amplifiers (EDFA's), which is based on heterodyne detection using acousto-optic (AO) switches. In order to avoid any optical surges in the EDFA's in the transmission lines, optical dummy pulses were added between the signal pulses by an AO switch to keep the probe power from the C-OTDR as uniform as possible. We achieved a large single-way dynamic range of 42 dB with 5 dBm less probe power. The measurable portion of the fiber spans was more than 80 km in optical transmission lines containing EDFA's. This is twice the previously reported value.

  5. Transmission performance of the double-sideband SCM optical label

    Science.gov (United States)

    Chen, Minghua; Zhou, Weiqing; Jia, Zhensheng; Xie, Shizhong

    2002-09-01

    Transmission performance of the optical label with the double-sideband subcarrier multiplexing is investigated using Volterra transfer function approach. It is shown that the phase shifts of the two sideband signal is induced jointly by the interaction between SCM component and payload component due to fiber dispersion and nonlinearity. This will cause the SCM label fading, and then harm to system performance.

  6. Neural Network-Based Multimode Fiber-Optic Information Transmission

    Science.gov (United States)

    Marusarz, Ronald K.; Sayeh, Mohammad R.

    2001-01-01

    A new technique for transmitting information through multimode fiber-optic cables is presented. This technique sends parallel channels through the fiber-optic cable, thereby greatly improving the data transmission rate compared with that of the current technology, which uses serial data transmission through single-mode fiber. An artificial neural network is employed to decipher the transmitted information from the received speckle pattern. Several different preprocessing algorithms are developed, tested, and evaluated. These algorithms employ average region intensity, distributed individual pixel intensity, and maximum mean-square-difference optimal group selection methods. The effect of modal dispersion on the data rate is analyzed. An increased data transmission rate by a factor of 37 over that of single-mode fibers is realized. When implementing our technique, we can increase the channel capacity of a typical multimode fiber by a factor of 6.

  7. Optical fiber transmission of high power excimer laser radiation.

    Science.gov (United States)

    Pini, R; Salimbeni, R; Vannini, M

    1987-10-01

    An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.

  8. Demonstration of optical steganography transmission using temporal phase coded optical signals with spectral notch filtering.

    Science.gov (United States)

    Hong, Xuezhi; Wang, Dawei; Xu, Lei; He, Sailing

    2010-06-07

    A novel approach is proposed and experimentally demonstrated for optical steganography transmission in WDM networks using temporal phase coded optical signals with spectral notch filtering. A temporal phase coded stealth channel is temporally and spectrally overlaid onto a public WDM channel. Direct detection of the public channel is achieved in the presence of the stealth channel. The interference from the public channel is suppressed by spectral notching before the detection of the optical stealth signal. The approach is shown to have good compatibility and robustness to the existing WDM network for optical steganography transmission.

  9. Optical transmission spectra in quasiperiodic multilayered photonic structure

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, F F de [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Albuquerque, E L [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Vasconcelos, M S [Departamento de Ciencias Exatas, Centro Federal de Educacao Tecnologica do Maranhao, 65025-001 Sao LuIs-MA (Brazil)

    2006-10-10

    Optical transmission spectra in quasiperiodic multilayered photonic structures, composed of both positive (SiO{sub 2}) and negative refractive index materials, are calculated by using a theoretical model based on the transfer matrix approach for normal incidence geometry. The quasiperiodic structures are substitutional sequences, characterized by the nature of their Fourier spectrum, which can be dense pure point (e.g. Fibonacci sequence) or singular continuous (e.g. Thue-Morse and double-period sequences). The transmission spectra for the case where both refractive indices can be approximated by a different constant show a unique mirror symmetrical profile, with no counterpart for the positive refractive index case, as well as a striking self-similar behaviour related to the Fibonacci sequence. For a more realistic frequency-dependent refractive index, the transmission spectra are characterized by a rich transmission profile of Bragg peaks with no more self-similarity or mirror symmetry.

  10. Optical transmission spectra in quasiperiodic multilayered photonic structure

    Science.gov (United States)

    de Medeiros, F. F.; Albuquerque, E. L.; Vasconcelos, M. S.

    2006-10-01

    Optical transmission spectra in quasiperiodic multilayered photonic structures, composed of both positive (SiO2) and negative refractive index materials, are calculated by using a theoretical model based on the transfer matrix approach for normal incidence geometry. The quasiperiodic structures are substitutional sequences, characterized by the nature of their Fourier spectrum, which can be dense pure point (e.g. Fibonacci sequence) or singular continuous (e.g. Thue-Morse and double-period sequences). The transmission spectra for the case where both refractive indices can be approximated by a different constant show a unique mirror symmetrical profile, with no counterpart for the positive refractive index case, as well as a striking self-similar behaviour related to the Fibonacci sequence. For a more realistic frequency-dependent refractive index, the transmission spectra are characterized by a rich transmission profile of Bragg peaks with no more self-similarity or mirror symmetry.

  11. Optical filters with fractal transmission spectra based on diffractive optics.

    Science.gov (United States)

    Mendoza-Yero, Omel; Mínguez-Vega, Gladys; Fernández-Alonso, Mercedes; Lancis, Jesús; Tajahuerce, Enrique; Climent, Vicent; Monsoriu, Juan A

    2009-03-01

    The duality between the axial irradiance distribution originated by any circularly symmetric diffracting aperture under monochromatic illumination and its diffracted spectral intensity at a fixed on-axis point under broadband illumination is highlighted and experimentally investigated. Two applications are derived from this basic result. On the one hand, we suggest the use of a broadband source and a spectrometer for a single-shot measurement of the axial response of pupil filters. Second, we implement a spectral filter having a transmission spectrum with a fractal structure of frequencies. Experimental results and potential applications in synthetic spectra designs are provided.

  12. High-Order Modulation for Optical Fiber Transmission

    CERN Document Server

    Seimetz, Matthias

    2009-01-01

    Catering to the current interest in increasing the spectral efficiency of optical fiber networks by the deployment of high-order modulation formats, this monograph describes transmitters, receivers and performance of optical systems with high-order phase and quadrature amplitude modulation. In the first part of the book, the author discusses various transmitter implementation options as well as several receiver concepts based on direct and coherent detection, including designs of new structures. Hereby, both optical and electrical parts are considered, allowing the assessment of practicability and complexity. In the second part, a detailed characterization of optical fiber transmission systems is presented, regarding a wide range of modulation formats. It provides insight in the fundamental behavior of different formats with respect to relevant performance degradation effects and identifies the major trends in system performance.

  13. Protocol independent transmission method in software defined optical network

    Science.gov (United States)

    Liu, Yuze; Li, Hui; Hou, Yanfang; Qiu, Yajun; Ji, Yuefeng

    2016-10-01

    With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.i., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). Using a proprietary protocol or encoding format is a way to improve information security. However, the flow, which carried by proprietary protocol or code, cannot go through the traditional IP network. In addition, ultra- high-definition video transmission service once again become a hot spot. Traditionally, in the IP network, the Serial Digital Interface (SDI) signal must be compressed. This approach offers additional advantages but also bring some disadvantages such as signal degradation and high latency. To some extent, HD-SDI can also be regard as a proprietary protocol, which need transparent transmission such as optical channel. However, traditional optical networks cannot support flexible traffics . In response to aforementioned challenges for future network, one immediate solution would be to use NFV technology to abstract the network infrastructure and provide an all-optical switching topology graph for the SDN control plane. This paper proposes a new service-based software defined optical network architecture, including an infrastructure layer, a virtualization layer, a service abstract layer and an application layer. We then dwell on the corresponding service providing method in order to implement the protocol-independent transport. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit the HD-SDI signal in the software-defined optical network.

  14. Optical transmission scanning for damage quantification in impacted GFRP composites

    Science.gov (United States)

    Khomenko, Anton; Karpenko, Oleksii; Koricho, Ermias G.; Haq, Mahmoodul; Cloud, Gary L.; Udpa, Lalita

    2016-04-01

    Glass fiber reinforced polymer (GFRP) composites constitute nearly 90% of the global composites market and are extensively used in aerospace, marine, automotive and construction industries. While their advantages of lightweight and superior mechanical properties are well explored, non-destructive evaluation (NDE) techniques that allow for damage/defect detection and assessment of its extent and severity are not fully developed. Some of the conventional NDE techniques for GFRPs include ultrasonics, X-ray, IR thermography, and a variety of optical techniques. Optical methods, specifically measuring the transmission properties (e.g. ballistic optical imaging) of specimens, provide noninvasive, safe, inexpensive, and compact solutions and are commonly used in biomedical applications. In this work, this technique is adapted for rapid NDE of GFRP composites. In its basic form, the system for optical transmission scanning (OTS) consists of a light source (laser diode), a photo detector and a 2D translation stage. The proposed technique provides high-resolution, rapid and non-contact OT (optical transmittance)-scans, and does not require any coupling. The OTS system was used for inspection of pristine and low-velocity impacted (damaged) GFRP samples. The OT-scans were compared with conventional ultrasonic C-scans and showed excellent agreement but with better resolution. Overall, the work presented lays the groundwork for cost-effective, non-contact, and rapid NDE of GFRP composite structures.

  15. Negative refractive index metamaterials aided by extraordinary optical transmission.

    Science.gov (United States)

    García-Meca, C; Ortuño, R; Rodríguez-Fortuño, F J; Martí, J; Martínez, A

    2009-04-13

    We study under which conditions extraordinary optical transmission (EOT) structures can be used to build negative refractive index media. As a result, we present a metamaterial with superimposed EOT and negative index at visible wavelengths. The tailoring process starting from a simple hole array until achieving the negative index is detailed. We also discuss the so-called fishnet metamaterial (previously linked to EOT) under the same prism. Using the ideas put forward in this work, other structures with negative index could be engineered in the optical or visible spectrum.

  16. Recent progress on high-speed optical transmission

    Directory of Open Access Journals (Sweden)

    Jianjun Yu

    2016-05-01

    Full Text Available The recently reported high spectral efficiency (SE and high-baud-rate signal transmission are all based on digital coherent optical communications and digital signal processing (DSP. DSP simplifies the reception of advanced modulation formats and also enables the major electrical and optical impairments to be processed and compensated in the digital domain, at the transmitter or receiver side. In this paper, we summarize the research progress on high-speed signal generation and detection and also show the progress on DSP for high-speed signal detection. We also report the latest progress on multi-core and multi-mode multiplexing.

  17. Transmission line resonance technique for eccentric core optical fibers

    Science.gov (United States)

    Georgantzos, E.; Boucouvalas, A. C.

    2016-12-01

    In several cases optical fibers in telecommunications have cores of non circular geometry. Fibre optic deformations appear in optical fibres for many reasons. Optical fibre core ellipticity for example where the fibre optic core is not perfectly circular due to fibre optic manufacturing tolerances, is measured and often is a problem. Optical fibre core eccentricity, where the fibre core is not on the axis of the fibre, but it is offset by a small length. This is another issue and very important for ensuring performance low loss splices and connector losses. Both of ellipticity and eccentricity are specified in accordance to international standards for fibre optic manufacturing telecommunications grade fibres. The present paper studies ellipticity and core eccentricity specifically and presents a new method for analysing their effect. We present an extension of the transmission line technique as a means of studying such fibers and deriving necessary parameters. Conformal mapping on the other hand is a simple mathematical tool by which we can generate sets of orthogonal two-dimensional coordinate systems. Shortly a conformal map of Cartesian two-dimensional space is defined by any analytical function W(z) where z, w, are: z = x + jy, W = θ + j φ The function deriving by the conformal mapping transformation h(θ ,φ )=| ∂w/∂z | = 1/|∂z/∂w|, can be used in order to define ∇A → and ∇×A → where A → is the magnetic or electric field in the derived orthogonal coordinate system. Useful conformal maps for fiber optics applications should have the property that the equation θ(x, y) = constant, is forming closed curves in a Cartesian two-dimensional space (x,y). If θ(x, y) = constant represents a set of co-eccentric circles, we obtain the normal case of conventional fibers with circular cores. If θ(x, y) = constant represents a set of eclipses, we are have the formation of elliptic core optical fibers. If θ(x, y) = constant represents a set of

  18. Remote actuation by optical power transmission in fibres

    Science.gov (United States)

    Avis, S. E.; Byron, K. C.

    1987-04-01

    Some preliminary experiments on the remote actuation of a servo-valve are described in which the power transmission medium is an optical fibre. Using a semiconductor laser or a Nd:YAG laser as the power source and silicon cells as the opto-electrical transducer, switching of the servo-valve has been observed at power levels of a few milliwatts over 800 m of fibre.

  19. Intermodal Energy Transfer in a Tapered Optical Fiber: Optimizing Transmission

    CERN Document Server

    Ravets, S; Kordell, P R; Wong-Campos, J D; Rolston, S L; Orozco, L A

    2013-01-01

    We present an experimental and theoretical study of the energy transfer between modes during the tapering process of an optical nanofiber through spectrogram analysis. The results allow optimization of the tapering process, and we measure transmission in excess of 99.95% for the fundamental mode. We quantify the adiabaticity condition through calculations and place an upper bound on the amount of energy transferred to other modes at each step of the tapering, giving practical limits to the tapering angle.

  20. Transmission Spectrum of an Optical Cavity Containing N Atoms

    CERN Document Server

    Leslie, S; Brown, K R; Stamper-Kurn, D M; Whaley, K B; Leslie, Sabrina; Shenvi, Neil; Brown, Kenneth R.; Stamper-Kurn, Dan M.

    2003-01-01

    The transmission spectrum of a high-finesse optical cavity containing an arbitrary number of trapped atoms is presented. We take spatial and motional effects into account and show that in the limit of strong coupling, the important spectral features can be determined for an arbitrary number of atoms, N. We also show that these results have important ramifications in limiting our ability to determine the number of atoms in the cavity.

  1. Optical differentiation wavefront sensing with binary pixelated transmission filters.

    Science.gov (United States)

    Qiao, J; Mulhollan, Z; Dorrer, C

    2016-05-02

    Sensors measuring the spatial phase of optical waves are widely used in optics. The optical differentiation wavefront sensor (ODWS) reconstructs the wavefront of an optical wave from wavefront slope measurements obtained by inducing linear field-transmission gradients in the far-field. Its dynamic range and sensitivity can be adjusted simply by changing the gradient slope. We numerically and experimentally demonstrate the possibility of implementing the spatially varying transmission gradient using distributions of small pixels that are either transparent or opaque. Binary pixelated filters are achromatic and can be fabricated with high accuracy at relatively low cost using commercial lithography techniques. We study the impact of the noise resulting from pixelation and binarization of the far-field filter for various test wavefronts and sensor parameters. The induced wavefront error is approximately inversely proportional to the pixel size. For an ODWS with dynamic range of 100 rad/mm over a 1-cm pupil, the error is smaller than λ/15 for a wide range of test wavefronts when using 2.5-μm pixels. We experimentally demonstrate the accuracy and consistency of a first-generation ODWS based on binary pixelated filters.

  2. Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Picher, Matthieu; Mazzucco, Stefano [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20740 (United States); Blankenship, Steve [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States); Sharma, Renu, E-mail: renu.sharma@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States)

    2015-03-15

    Here, we present a measurement platform for collecting multiple types of spectroscopy data during high-resolution environmental transmission electron microscopy observations of dynamic processes. Such coupled measurements are made possible by a broadband, high-efficiency, free-space optical system. The critical element of the system is a parabolic mirror, inserted using an independent hollow rod and placed below the sample holder which can focus a light on the sample and/or collect the optical response. We demonstrate the versatility of this optical setup by using it to combine in situ atomic-scale electron microscopy observations with Raman spectroscopy. The Raman data is also used to measure the local temperature of the observed sample area. Other applications include, but are not limited to: cathodo- and photoluminescence spectroscopy, and use of the laser as a local, high-rate heating source. - Highlights: • Broadband, high-efficiency design adaptable to other electron microscopes. • Raman spectroscopy integrated with environmental transmission electron microscopy. • Raman spectra peak frequency shifts enable measurement of local sample temperature. • Multiple types of optical spectroscopy enabled, e.g. cathodoluminescence.

  3. DWDM VSB modulation-format optical transmission: Effects of optical filtering and electrical equalization

    Science.gov (United States)

    Binh, Le Nguyen

    2008-10-01

    The transmission of 40 Gb/s wavelength multiplexed channels under vestigial single side band modulation format is transmitted over long haul optically amplified fiber systems. Bit-error-rate (BER) of 10 -12 or better can be achieved across all channels. Optical filters are designed with asymmetric roll-off bands. Simulations of the transmission performance, BER versus receiver sensitivity are demonstrated with wavelength channel spacing of 20-40 GHz. An optical filter, whose passband is 28 GHz and 20 dB cut-off band, performs best for 40 Gb/s bit rate due to optimum filtering and minimum noise contribution. Furthermore the single-sideband property of VSB format can assist linear equalization by electronic processing. The transmission performance is accurately evaluated based on the eye opening using a fast statistical method based on an equivalent Gaussian probability density distribution (pdf) which is derived from multiple peaks pdf of distorted eye diagram.

  4. Adaptive Quality of Transmission Control in Elastic Optical Network

    Science.gov (United States)

    Cai, Xinran

    Optical fiber communication is becoming increasingly important due to the burgeoning demand in the internet capacity. However, traditional wavelength division multiplexing (WDM) technique fails to address such demand because of its inefficient spectral utilization. As a result, elastic optical networking (EON) has been under extensive investigation recently. Such network allows sub-wavelength and super-wavelength channel accommodation, and mitigates the stranded bandwidth problem in the WDM network. In addition, elastic optical network is also able to dynamically allocate the spectral resources of the network based on channel conditions and impairments, and adaptively control the quality of transmission of a channel. This application requires two aspects to be investigated: an efficient optical performance monitoring scheme and networking control and management algorithms to reconfigure the network in a dynamic fashion. This thesis focuses on the two aspects discussed above about adaptive QoT control. We demonstrated a supervisory channel method for optical signal to noise ratio (OSNR) and chromatic dispersion (CD) monitoring. In addition, our proof-of-principle testbed experiments show successful impairment aware reconfiguration of the network with modulation format switching (MFS) only and MFS combined with lightpath rerouting (LR) for hundred-GHz QPSK superchannels undergoing time-varying OSNR impairment.

  5. Optical nonreciprocal transmission in an asymmetric silicon photonic crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zheng; Chen, Juguang; Ji, Mengxi; Huang, Qingzhong; Xia, Jinsong; Wang, Yi, E-mail: yingwu2@126.com, E-mail: ywangwnlo@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Wu, Ying, E-mail: yingwu2@126.com, E-mail: ywangwnlo@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2015-11-30

    An optical nonreciprocal transmission (ONT) is realized by employing the nonlinear effects in a compact asymmetric direct-coupled nanocavity-waveguide silicon photonic crystal structure with a high loaded quality factor (Q{sub L}) of 42 360 and large extinction ratio exceeding 30 dB. Applying a single step lithography and successive etching, the device can realize the ONT in an individual nanocavity, alleviating the requirement to accurately control the resonance of the cavities. A maximum nonreciprocal transmission ratio of 21.1 dB as well as a working bandwidth of 280 pm in the telecommunication band are obtained at a low input power of 76.7 μW. The calculated results by employing a nonlinear coupled-mode model are in good agreement with the experiment.

  6. Secure communication in fiber optic systems via transmission of broad-band optical noise.

    Science.gov (United States)

    Buskila, O; Eyal, A; Shtaif, M

    2008-03-03

    We propose a new scheme for data encryption in the physical layer. Our scheme is based on the distribution of a broadband optical noise-like signal between Alice and Bob. The broadband signal is used for the establishment of a secret key that can be used for the secure transmission of information by using the one-time-pad method. We characterize the proposed scheme and study its applicability to the existing fiber-optics communications infrastructure.

  7. FSK Modulation Scheme for High-Speed Optical Transmission

    Institute of Scientific and Technical Information of China (English)

    Nan Chi; Wuliang Fang; Yufeng Shao; Junwen Zhang; Li Tao

    2012-01-01

    In this paper, we describe the generation, detection, and performance of frequency-shift keying (FSK) for high-speed optical transmission and label switching. A non-return-to-zero (NRZ) FSK signal is generated by using two continuous-wave (CW) lasers, one Mach-Zehnder modulator (MZM), and one Mach-Zehnder delay interferometer (MZDI). An RZ-FSK signal is generated by cascading a dual-arm MZM, which is driven by a sinusoidal voltage at half the bit rate. Demodulation can be achieved on 1 bit rate through one MZDI or an array waveguide grating (AWG) demultiplexer with balanced detection. We perform numerical simulation on two types of frequency modulation schemes using MZM or PM, and we determine the effect of frequency tone spacing (FTS) on the generated FSK signal. In the proposed scheme, a novel frequency modulation format has transmission advantages compared with traditional modulation formats such as RZ and differential phase-shift keying (DPSK), under varying dispersion management. The performance of an RZ-FSK signal in a 4 x 40 Gb/s WDM transmission system is discussed. We experiment on transparent wavelength conversion based on four-wave mixing (FWM) in a semiconductor optical amplifier (SOA) and in a highly nonlinear dispersion shifted fiber (HNDSF) for a 40 Gb/s RZ-FSK signal. The feasibility of all-optical signal processing of a high-speed RZ-FSK signal is confirmed. We also determine the receiver power penalty for the RZ-FSK signal after a 100 km standard single-mode fiber (SMF) transmission link with matching dispersion compensating fiber (DCF), under the post-compensation management scheme. Because the frequency modulation format is orthogonal to intensity modulation and vector modulation (polarization shift keying), it can be used in the context of the combined modulation format to decrease the data rate or enhance the symbol rate. It can also be used in orthogonal label-switching as the modulation format for the payload or the label. As an example, we

  8. Transmission and Distribution of Optical Field in Prism Coupler

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C Q; Chen, M [College of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang 414006 (China); Liu, J; Wan, Z M; Luo, Z M [College of Information and Communication Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Tian, P, E-mail: namecqh@yahoo.com.cn [College of Optoelectronic Science and Engineering, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2011-02-01

    Transmission and distribution characteristics of optical field in prism coupler are studies, and the phase matching function of prism coupler is deduced based on coupled wave theory. It is shown that the stable light field distribution and mode pattern are determined by its own geometric and dielectric parameters, but have nothing to do with the categories of incident light sources. It is also found that the coupling effect would generate between waveguides through evanescent field. Our numerical simulation is based on the finite difference time domain method with perfectly matched layer absorbing boundary condition. The simulation program is compiled in MATLAB. The simulation results are analyzed carefully.

  9. Transmission Performance Analysis of Digital Wire and Wireless Optical Links in Local and Wide Areas Optical Networks

    CERN Document Server

    Mohamed, Abd El Naser A; Rashed, Ahmed Nabih Zaki; Nabawy, Amina E M El

    2009-01-01

    In the present paper, the transmission performance analysis of digital wire and wireless optical links in local and wide areas optical networks have been modeled and parametrically investigated over wide range of the affecting parameters. Moreover, we have analyzed the basic equations of the comparative study of the performance of digital fiber optic links with wire and wireless optical links. The development of optical wireless communication systems is accelerating as a high cost effective to wire fiber optic links. The optical wireless technology is used mostly in wide bandwidth data transmission applications. Finally, we have investigated the maximum transmission distance and data transmission bit rates that can be achieved within digital wire and wireless optical links for local and wide areas optical network applications.

  10. Quasi-Optical Control of Intense Microwave Transmission

    CERN Document Server

    Hirshfield, Jay L

    2005-01-01

    This volume assembles the texts of presentations given at the NATO-sponsored Advanced Research Workshop on Quasi-Optical Transmission of High-Power Microwaves, held in Nizhny Novgorod, Russia in February 2004. The presentations bridge a wide range of technical areas, but share common tools of analysis and design. Applications of quasi-optics extend to the use of high-power microwaves—including millimeter-waves— for radar and communications (especially deep space millimeter-wave systems, space debris detection radar, and radar for the detection of small targets moving over heavy clutter); particle accelerators (especially for a future high-acceleration-gradient electron-positron collider); plasma research (especially for controlled nuclear fusion and waste decontamination); and material processing (in particular, ceramic sintering with millimeter-waves, and the coating of metal surfaces with protective dielectric films.). Scientists and engineers working in any of these areas should benefit significantly f...

  11. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    Science.gov (United States)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 μm multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  12. Evaluation of Fibre Lifetime in Optical Ground Wire Transmission Lines

    Science.gov (United States)

    Grunvalds, R.; Ciekurs, A.; Porins, J.; Supe, A.

    2017-06-01

    In the research, measurements of polarisation mode dispersion of two OPGWs (optical ground wire transmission lines), in total four fibres, have been carried out, and the expected lifetime of the infrastructure has been assessed on the basis of these measurements. The cables under consideration were installed in 1995 and 2011, respectively. Measurements have shown that polarisation mode dispersion values for cable installed in 1995 are four times higher than that for cable installed in 2011, which could mainly be explained by technological differences in fibre production and lower fibre polarisation mode dispersion requirements in 1995 due to lack of high-speed (over 10 Gbit/s) optical transmission systems. The calculation methodology of non-refusal work and refusal probabilities, using the measured polarisation mode dispersion parameters, is proposed in the paper. Based on reliability calculations, the expected lifetime is then predicted, showing that all measured fibres most likely will be operational within minimum theoretical service life of 25 years accepted by the industry.

  13. Optical transmission theory for metal-insulator-metal periodic nanostructures

    Science.gov (United States)

    Blanchard-Dionne, Andre-Pierre; Meunier, Michel

    2017-01-01

    A semi-analytical formalism for the optical properties of a metal-insulator-metal periodic nanostructure using coupled-mode theory is presented. This structure consists in a dielectric layer in between two metallic layers with periodic one-dimensional nanoslit corrugation. The model is developed using multiple-scattering formalism, which defines transmission and reflection coefficients for each of the interface as a semi-infinite medium. Total transmission is then calculated using a summation of the multiple paths of light inside the structure. This method allows finding an exact solution for the transmission problem in every dimension regime, as long as a sufficient number of diffraction orders and guided modes are considered for the structure. The resonant modes of the structure are found to be related to the metallic slab only and to a combination of both the metallic slab and dielectric layer. This model also allows describing the resonant behavior of the system in the limit of a small dielectric layer, for which discontinuities in the dispersion curves are found. These discontinuities result from the out-of-phase interference of the different diffraction orders of the system, which account for field interaction for both inner interfaces of the structure.

  14. Optical vortex discrimination with a transmission volume hologram

    Energy Technology Data Exchange (ETDEWEB)

    Gruneisen, Mark T [Air Force Research Laboratory, Directed Energy Directorate, Kirtland AFB, NM 87117 (United States); Dymale, Raymond C; Stoltenberg, Kurt E [Boeing Company, PO Box 5670, Albuquerque, NM 87185 (United States); Steinhoff, Nicholas [Optical Sciences Company, 1341 S Sunkist St., Anaheim, CA 92806 (United States)

    2011-08-15

    Transmissive volume holograms are considered as mode-selective optical elements for the de-multiplexing and detecting of optical vortex modes according to the topological charge or mode number. Diffraction of vortex modes by a fundamental mode hologram is modeled using a physical optics model that treats the volume hologram as an angle-dependent transfer function. Diffracted irradiance profiles and diffraction efficiencies are calculated numerically as a function of the incident mode number. The results of the model are compared with experimental results obtained with volume holograms of fundamental and higher-order vortex modes. When considered as a function of detuning between the incident and recorded mode numbers, the measured diffraction efficiencies are found to be invariant with respect to the recorded mode number, provided that the order difference remains unchanged, and in close agreement with the predictions of the model. Measurements are made with a 1.3 mm thick permanent photo-thermo-refractive glass hologram and a 9 mm thick re-writable photorefractive lithium niobate hologram. A liquid-crystal spatial light modulator generates the vortex modes used to record and read the holograms. The results indicate that a simple volume hologram can discriminate between vortex modes; however, adjacent mode discrimination with low crosstalk would require a very thick hologram. Furthermore, broadening of the vortex angular spectrum, due to diffraction at a finite aperture, can adversely affect diffraction efficiencies.

  15. Novel scheme enabling broadcast signal transmission in WDM passive optical network

    Institute of Scientific and Technical Information of China (English)

    Xuejiao Ma; Chaoqin Gan

    2011-01-01

    @@ We present a novel method for providing broadcast signal transmission in a wavelength division multiplex-ing passive optical network (WDM-PON).An unmodulated optical carrier for downstream transmission and a pair of unmodulated single-side band subcarriers are utilized for broadcast delivery and upstream transmission, respectively.System performance at 2.5-Gb/s downlupstream and 2.5-Gb/s broadcast trans-mission is also investigated.%We present a novel method for providing broadcast signal transmission in a wavelength division multiplexing passive optical network (WDM-PON).An unmodulated optical carrier for downstream transmission and a pair of unmodulated single-side band subcarriers are utilized for broadcast delivery and upstream transmission, respectively.System performance at 2.5-Gb/s down/upstream and 2.5-Gb/s broadcast transmission is also investigated.

  16. Transmission electron microscope sample holder with optical features

    Science.gov (United States)

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  17. Photoluminescence and optical transmission of diffusion-pump oils.

    Science.gov (United States)

    Kroes, R. L.

    1973-01-01

    The photoluminescence and optical transmission of the four widely used diffusion-pump oils, DC-705, DC-704, Convalex-10, and Convoil-20, were measured. Each of the oils was found to be transparent throughout the visible region, showed some absorption in the near-UV region, and became very opaque below approximately 300 nm. Both Convalex-10 and Convoil-20 turned yellow after exposure to UV light. No such change was noted in DC-705 or DC-704. Photoluminescence was produced in each of the four oils when irradiated with UV light. Both DC-705 and DC-704 had a nearly identical luminescence spectra that peaked at 350 nm. The spectra of Convalex-10 and Convoil-20 were fairly complex, with several peaks in the visible region.

  18. Optically oriented electron spin transmission across ferromagnet/semiconductor interfaces

    Science.gov (United States)

    Taniyama, T.; Suzuki, I.; Wada, E.; Shirahata, Y.; Naito, T.; Itoh, M.; Yamaguchi, M.

    2011-10-01

    Electron spin transmission across ferromagnetic metal/semiconductor interfaces with different ferromagnetic contacts, i.e., Fe and FeGa, is studied using optical spin orientation method. The bias dependence of spin dependent photocurrent, which is the difference between the photocurrents excited with left- and right- handed circularly polarized lights, is found to show a dip-like feature at -0.058 and 0.021 V for Fe and FeGa contacts, respectively. The origin of the bias dependence of the spin dependent photocurrent is discussed on the basis of the Breit-Wigner type resonant tunneling process via interface resonant states, comparing the results for the both contacts. The results also indicate that the control of interface states is crucial to achieve efficient spin filtering effect at the ferromagnet/semiconductor interfaces.

  19. A novel optical transmission link with DHT-based constant envelope optical OFDM signal

    Science.gov (United States)

    Ma, Jianxin; Liang, Hao

    2013-07-01

    In this paper, we have proposed a novel optical OFDM transmission link that takes advantages of discrete Hartley Transform (DHT) and constant envelope (CE) modulation, obtaining DHT-based constant envelope optical OFDM. The numerical results show that this design achieves better performance when compared with conventional O-OFDM in terms of bit error rate (BER) and peak-to-average power ratio (PAPR). The impact of phase modulation index (PMI) on both PAPR and noise tolerance is investigated. Since the scheme has simplified design, it is believed to be a cost-effective in the practical implement.

  20. Exergetic assessment of transmission-concentrated solar energy systems via optical fi bres for building applications

    OpenAIRE

    ZIDANI, Chafika; BENYOUCEF, Boumédiène; MADINI, Nassima

    2012-01-01

    Optical fibressolar energy transmission and concentration provide a flexible way of handling concentrated solar energy. Solar lighting with Fibre Optic Bundles (FOBs) can be considered a promising option for energy-efficient green buildings. This study deals with ...

  1. Polarized left-handed extraordinary optical transmission of subterahertz waves.

    Science.gov (United States)

    Beruete, Miguel; Sorolla, Mario; Navarro-Cía, Miguel; Campillo, Igor

    2007-06-25

    In this paper we design and measure a metamaterial polarizing device working in the sub-terahertz range. The polarizer is based on a modified version of our previous miniaturized Stacked Hole Array (SHA) structure, an arrangement that combines Extraordinary Optical Transmission (EOT) and Left-Handed Metamaterial (LHM) propagation even under Fresnel illumination. Here, we use a self complementary screen by connecting the holes of an EOT structure. Importantly, EOT remains and simultaneously total reflection is obtained for the orthogonal component. Moreover, by computing the dispersion diagram, we demonstrate that LHM propagation can be achieved for the principal polarization within the stop band of the orthogonal component, which propagates in other bands as a standard forward wave. Finally, we check our conjectures by measuring the transmission and reflection coefficients of screens milled on a low-loss microwave substrate. Measurements have been taken for 1 to 6 stacked wafers and they show clearly that the stack acts as a polarizer with left-handed characteristic. Our results open the way to design of novel polarization control metamaterials at Terahertz wavelengths.

  2. Effects of optical layer impairments on 2.5 Gb/s optical CDMA transmission.

    Science.gov (United States)

    Feng, H; Mendez, A; Heritage, J; Lennon, W

    2000-07-03

    We conducted a computer simulation study to assess the effects of optical layer impairments on optical CDMA (O-CDMA) transmission of 8 asynchronous users at 2.5 Gb/s each user over a 214-km link. It was found that with group velocity dispersion compensation, two other residual effects, namely, the nonzero chromatic dispersion slope of the single mode fiber (which causes skew) and the non-uniform EDFA gain (which causes interference power level to exceed signal power level of some codes) degrade the signal to multi-access interference (MAI) ratio. In contrast, four wave mixing and modulation due to the Kerr and Raman contributions to the fiber nonlinear refractive index are less important. Current wavelength-division multiplexing (WDM) technologies, including dispersion management, EDFA gain flattening, and 3 rd order dispersion compensation, are sufficient to overcome the impairments to the O-CDMA transmission system that we considered.

  3. Noise and signal interference in optical fiber transmission systems an optimum design approach

    CERN Document Server

    Bottacchi, Stefano

    2008-01-01

    A comprehensive reference to noise and signal interference in optical fiber communications Noise and Signal Interference in Optical Fiber Transmission Systems is a compendium on specific topics within optical fiber transmission and the optimization process of the system design. It offers comprehensive treatment of noise and intersymbol interference (ISI) components affecting optical fiber communications systems, containing coverage on noise from the light source, the fiber and the receiver. The ISI is modeled with a statistical approach, leading to new useful computational m

  4. Study on New Concatenated Code in WDM Optical Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-guo; JIANG Ze; MAO You-ju; YE Wen-wei

    2007-01-01

    A new concatenated code of RS(255,239)+BCH(2 040,1 930) code to be suitable for WDM optical transmission systems is proposed.The simulation results show that this new concatenated code,compared with the RS(255,239)+CSOC(k0/n0=6/7,J=8) code in ITU-T G.75.1,has a lower redundancy and better error-correction performance,furthermore,its net coding gain(NCG) is respectively 0.46 dB,0.43 dB more than that of RS(255,239)+CSOC(k0/n0 =6/7,J=8) code and BCH(3 860,3 824)+BCH(2 040,1 930) code in ITU-T G.75.1 at the third iteration for the bit error rate(BER) of 10-12.Therefore,the new super forward error correction(Super-FEC) concatenated code can be better used in ultra long-haul,ultra large-capacity and ultra high-speed WDM optical communication systems.

  5. Generalized OFDM (GOFDM) for ultra-high-speed optical transmission.

    Science.gov (United States)

    Djordjevic, Ivan; Arabaci, Murat; Xu, Lei; Wang, Ting

    2011-03-28

    We propose a coded N-dimensional modulation scheme suitable for ultra-high-speed serial optical transport. The proposed scheme can be considered as a generalization of OFDM, and hence, we call it as generalized OFDM (GOFDM). In this scheme, the orthogonal subcarriers are used as basis functions and the signal constellation points are defined over this N-dimensional linear space. To facilitate implementation, we propose using N-dimensional pulse-amplitude modulation (ND-PAM) as the signal constellation diagram, which is obtained as the N-ary Cartesian product of one-dimensional PAM. In conventional OFDM, QAM/PSK signal constellation points are transmitted over orthogonal subcarriers and then they are multiplexed together in an OFDM stream. Individual subcarriers, therefore, carry N parallel QAM/PSK streams. In the proposed GOFDM scheme instead, an N-dimensional signal constellation point is transmitted over all N subcarriers simultaneously. When some of the subcarriers are severely affected by channel impairments, the constellation points carried by those subcarriers may be lost in the conventional OFDM. In comparison, under such conditions, the overall signal constellation point will face only small distortion in GOFDM and it can be recovered successfully using the information on the other high fidelity subcarriers. Furthermore, because the channel capacity is a logarithmic function of signal-to-noise ratio but a linear function of the number of dimensions, the spectral efficiency of optical transmission systems can be improved with GOFDM.

  6. Optical Constants of Planetary Analogs Using KBr Pellet Transmission

    Science.gov (United States)

    Hansen, G. B.; Hibbitts, C. A.

    2002-12-01

    Optical Constants of Planetary Analogs Using KBr Pellet Transmission G. B. Hansen, C. A. Hibbitts Optical constants of bulk materials are needed for radiative transfer models used to simulate remote sensing measurements. Many minerals are difficult orimpossible to study in bulk form, leading to various attempts to derive optical constants in other ways (e.g. measuring the Fresnel reflection from a polished or packed surface, which is not sensitive to regions of small absorption). We are starting a campaign to remeasure, or measure for the first time, many planetary analog materials (clays, oxyhydroxides, etc.) using a potassium bromide pellet technique, where the mineral powder is sparsely dispersed in KBr matrix such that the pellet is transparent through much of the mid-infrared (2.5-30 μm). The strongly absorbing regions can be measured if the grain size is small enough, and the weakly absorbing regions are measured by increasing the density of particles. The KBr pellet method has long been used because scattering at the matrix-particle interface is minimized due to the similarly high real indices of refraction between the matrix and particles, but interpretation of the measured extinction is still not straightforward because one is not measuring the absorption of a thin bulk film, but rather the absorption extinction of particles of comparable size to the wavelength. There is also the possible presence of scattering voids or bubbles in the matrix. In our case, there is also a weak absorption spectrum present due to impurities in the KBr powder. We will present the results from our first measurements of the clay Montmorillionite. The extinction of the Montmorillionite cloud in an absorbing medium will be modeled using Mie scattering and a full plane parallel radiative transfer model, utilizing available information on the size distribution and densities of the powder. The measurements will be matched by adjusting the optical constants input into the model. The

  7. A special issue on High.Speed Optical Transmission and Processing

    Institute of Scientific and Technical Information of China (English)

    Jian WANG

    2013-01-01

    The rapid growth in network capacity and traffic rates raises the significance of high-speed optical transmission and processing. Recent progress in optical communication systems in relation to multiplexing technologies in different degrees of freedom, advanced multi-level modulation formats, coherent detection and digital signal processing has facilitated dramatic increases in transmission capacity. To be compatible with high-speed optical transmission, high- speed optical processing has gained increased interest to enable fast data manipulation in the optical domain and avoid cumbersome optical-electrical-optical conversions at network nodes. Recent progress in nonlinear-optical devices has led to enhanced efficiency, flexibility and functionality of ultrafast nonlinear-optical signal processing. It is expected that these advances in high-speed optical transmission and processing will pave the way to achieve superior performance of high-speed optical networks. It is our intention to bring the research community's attention to these hot topics in optical communication systems and networks. In this "Special Issue on High-Speed Optical Transmission and Processing", 8 review articles and 2 research articles focusing on relevant subjects by internationally active groups in the field are specially presented.

  8. Optical transmission of PMMA optical fibres exposed to high intensity UVA and visible blue light

    Science.gov (United States)

    Alobaidani, A. D.; Furniss, D.; Johnson, M. S.; Endruweit, A.; Seddon, A. B.

    2010-05-01

    Optical transmission of PMMA (polymethylmethacrylate) POF (polymer optical fibre) in the spectral range from 280 to 450 nm is investigated with a high radiation emission source comprising a mercury lamp delivering 40 W/cm 2 at the PMMA POF launch face. The heat generated from the radiation source causes a sudden drop in the launched radiation due to thermal-oxidation and photo-degradation of the launch face of the PMMA POF; this results in a loss of 53% of the total launched power within 13 min of exposure to the source. The thermal-oxidation degradation is controlled by a cooling device which improves the transmission stability of the fibre. However, photo-degradation is still active and causes a loss in power of 7% in 13 min. The spectral output of the transmitted radiation through the PMMA POF was monitored and indicates the variation in optical loss with wavelength. High rates of nominal absorption for the irradiated PMMA POF are found below 320 nm wavelength. From the Beer-Lambert law, the photo-degradation effect with time of a fixed path length of PMMA POF is described by the absorption coefficient ( αλ, cm -1) . The nominal absorption coefficient αλ values in the range 335-368 nm wavelength are found to be higher after 1 h of irradiation than the values in the range 406-438 nm. However, the relative change in the nominal absorption coefficient Δ αλ is greater at 438 nm than at 335 nm, 368 or 406 nm. After 1 h of irradiation with the cooling device in place, the PMMA POF transmission was reduced to 44.8% of its initial value; this recovered to a maximum of 86% of the original transmission of the total launched power after 5 weeks in ambient conditions.

  9. Effects of the Planar Optical Waveguide Thickness on the Transmission Attenuation①

    Institute of Scientific and Technical Information of China (English)

    WANGJian; SUHansong

    1997-01-01

    By analyzing and computing,according to the wave theory of planar optical waveguide attenuation,a new opinion is put forward.A series of transmission atteenuation with waveguide film-thickness are given and it illustrates that optical transmission is not carrying out efficiently within some waveguide film-thickness.

  10. Investigating the Fabrication Imperfections of Plasmonic Nanohole Arrays and Its Effect on the Optical Transmission Spectra

    Directory of Open Access Journals (Sweden)

    Amr M. Mahros

    2015-01-01

    Full Text Available We investigate the extraordinary optical transmission spectra of thin gold films perforated with imperfect nanohole arrays using the finite difference time domain (FDTD method. Exponential shapes for the nanohole sidewalls are used. To the best of our knowledge, such investigation of transmission spectra of imperfect nanohole arrays has not previously been demonstrated. It was found that the asymmetry between the two openings of the circular nanoholes or bending to their sidewalls strongly modifies both the intensity and resonance positions of the transmission spectra. Furthermore, the results of this study assist in explaining the technicality of extraordinary optical transmission phenomenon and why some experimental results on transmission differ from those expected.

  11. Real-time all-optical OFDM transmission system based on time-domain optical fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Kong, Deming; Røge, Kasper Meldgaard

    2014-01-01

    We propose a novel simple all-optical OFDM transmission system based on time-domain OFT using time-lenses. A real-time 160 Gbit/s DPSK OFDM transmission with 16 decorrelated data subcarriers is successfully demonstrated over 100 km.......We propose a novel simple all-optical OFDM transmission system based on time-domain OFT using time-lenses. A real-time 160 Gbit/s DPSK OFDM transmission with 16 decorrelated data subcarriers is successfully demonstrated over 100 km....

  12. Bioinspired Superhydrophobic Highly Transmissive Films for Optical Applications.

    Science.gov (United States)

    Vüllers, Felix; Gomard, Guillaume; Preinfalk, Jan B; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce; Hölscher, Hendrik; Kavalenka, Maryna N

    2016-11-01

    Inspired by the transparent hair layer on water plants Salvinia and Pistia, superhydrophobic flexible thin films, applicable as transparent coatings for optoelectronic devices, are introduced. Thin polymeric nanofur films are fabricated using a highly scalable hot pulling technique, in which heated sandblasted steel plates are used to create a dense layer of nano- and microhairs surrounding microcavities on a polymer surface. The superhydrophobic nanofur surface exhibits water contact angles of 166 ± 6°, sliding angles below 6°, and is self-cleaning against various contaminants. Additionally, subjecting thin nanofur to argon plasma reverses its surface wettability to hydrophilic and underwater superoleophobic. Thin nanofur films are transparent and demonstrate reflection values of less than 4% for wavelengths ranging from 300 to 800 nm when attached to a polymer substrate. Moreover, used as translucent self-standing film, the nanofur exhibits transmission values above 85% and high forward scattering. The potential of thin nanofur films for extracting substrate modes from organic light emitting diodes is tested and a relative increase of the luminous efficacy of above 10% is observed. Finally, thin nanofur is optically coupled to a multicrystalline silicon solar cell, resulting in a relative gain of 5.8% in photogenerated current compared to a bare photovoltaic device.

  13. Giga-bit optical data transmission module for Beam Instrumentation

    CERN Document Server

    Roedne, L T; Cenkeramaddi, L R; Jiao, L

    Particle accelerators require electronic instrumentation for diagnostic, assessment and monitoring during operation of the transferring and circulating beams. A sensor located near the beam provides an electrical signal related to the observable quantity of interest. The front-end electronics provides analog-to-digital conversion of the quantity being observed and the generated data are to be transferred to the external digital back-end for data processing, and to display to the operators and logging. This research project investigates the feasibility of radiation-tolerant giga-bit data transmission over optic fibre for beam instrumentation applications, starting from the assessment of the state of the art technology, identification of challenges and proposal of a system level solution, which should be validated with a PCB design in an experimental setup. Radiation tolerance of 10 kGy (Si) Total Ionizing Dose (TID) over 10 years of operation, Bit Error Rate (BER) 10-6 or better. The findings and results of th...

  14. Plasmonic control of extraordinary optical transmission in the infrared regime

    Science.gov (United States)

    Sangiao, S.; Freire, F.; de León-Pérez, F.; Rodrigo, S. G.; De Teresa, J. M.

    2016-12-01

    We demonstrate that the spectral location of extraordinary optical transmission (EOT) resonances in metallic arrays of rectangular holes can be plasmonically tuned in the near and mid-infrared ranges. The experiments have been performed on patterned gold films. We focus on a subset of localized resonances occurring close to the cut-off wavelength of the holes, λ c. Metals are usually regarded as perfect electric conductors in the infrared regime, with an EOT cut-off resonance found around λ c = 2 L for rectangular holes (L being the long edge). For real metals, the penetration of the electromagnetic fields is simply seen as effectively enlarging L. However, by changing the hole short edge, we have found that λ c varies due to the excitation of gap surface plasmon polaritons. Finite-element calculations confirm that in these high aspect ratio rectangles with short edges two important aspects have to be taken into account in order to explain the experiments: the finite conductivity of the metal and the excitation of gap-surface plasmons inside the nanoholes.

  15. Holographic optical elements recorded in silver halide sensitized gelatin emulsions. Part I. Transmission holographic optical elements.

    Science.gov (United States)

    Kim, J M; Choi, B S; Kim, S I; Kim, J M; Bjelkhagen, H I; Phillips, N J

    2001-02-10

    Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOE's). The drawback of DCG is its low sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-high-resolution silver halide emulsions. An optimized processing technique for transmission HOE's recorded in these materials is introduced. Diffraction efficiencies over 90% can be obtained for transmissive diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOE's.

  16. Hyperbola-parabola primary mirror in Cassegrain optical antenna to improve transmission efficiency.

    Science.gov (United States)

    Zhang, Li; Chen, Lu; Yang, HuaJun; Jiang, Ping; Mao, Shengqian; Caiyang, Weinan

    2015-08-20

    An optical model with a hyperbola-parabola primary mirror added in the Cassegrain optical antenna, which can effectively improve the transmission efficiency, is proposed in this paper. The optimum parameters of a hyperbola-parabola primary mirror and a secondary mirror for the optical antenna system have been designed and analyzed in detail. The parabola-hyperbola primary structure optical antenna is obtained to improve the transmission efficiency of 10.60% in theory, and the simulation efficiency changed 9.359%. For different deflection angles to the receiving antenna with the emit antenna, the coupling efficiency curve of the optical antenna has been obtained.

  17. Design and Realization of Phased Array Radar Optical Fiber Transmission System

    Institute of Scientific and Technical Information of China (English)

    HU Shan-qing; LIU Feng; LONG Teng

    2007-01-01

    One optical fiber transmission system is designed.The modularization optical fiber transmission adapters were utilized in the system,so the system structure could be flexibly scalable.The sub-array adapter and signal processor adapter were designed and realized utilizing the new field programmable gate array (FPGA) which could drive the optical transceiver.The transmission agreement was designed based on the data stream.In order to solve the signal synchronization problem of the optical fiber transmitted phased array radar,a method named synchronous clock was designed.The fiber transmission error code rate of the system was zero with an experimental transmission velocity of 800 Mbit/s.The phased array radar system has detected the airplane target,thus validated the feasibility of the design method.

  18. Optimization of the transmission system for wavelength routed optical network: trade-off between node complexity and transmission channel utilization

    DEFF Research Database (Denmark)

    Limal, Emmanuel; Hjelme, Dag Roar; Stubkjær, Kristian Elmholdt

    1998-01-01

    We study the influence of the number of wavelengths per fibre and the line bit rate on network dimensions and transmission capacity utilisation for wavelength routed optical transport networks. The networks considered are of European scale, and the traffic matrices used are projections of a traffic...

  19. Multirate IP traffic transmission in flexible access networks based on optical FFH-CDMA

    DEFF Research Database (Denmark)

    Raddo, Thiago R.; Sanches, Anderson L.; Tafur Monroy, Idelfonso

    2016-01-01

    In this paper, we propose a new IP transmission architecture over optical fast frequency hopping code-division multiple-access (OFFH-CDMA) network capable of supporting multirate transmissions for applications in flexible optical access networks. The proposed network architecture is independent...... transmission rate. Furthermore, to evaluate the network performance, we derive new expressions for the decoder bit error rate (BER), total BER, packet error rate (PER), and packet throughput. We analyze the performance of a two-class OFFH-CDMA packet network, where multirate transmissions are achieved via...

  20. Cable television transmission over a 1550-nm infrared indoor optical wireless link

    Science.gov (United States)

    Sakib Chowdhury, M. I.; Kavehrad, Mohsen; Zhang, Weizhi

    2013-10-01

    We experimentally demonstrate transmission of cable television (CATV) radio frequency signals over a pointed indoor optical wireless link. The length of the optical link was 15 m. Collimators used at both the transmitter and the receiver sides required good alignment before sufficient optical power could be received. The system was placed at a height of 2 m, which is more than average human height, so human movements throughout the room did not obstruct the link. The optical wireless propagation path was almost lossless. The originality in this experimental demonstration is the transmission of full range of CATV signals compared to other works in this area. This experiment of radio over free-space optics showed that point-to-point indoor optical wireless links can be utilized as an alternative means for transmission of multimedia data.

  1. Optical transmission spectra in symmetrical Fibonacci photonic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Mauriz, P.W.; Vasconcelos, M.S. [Departamento de Ciencias Exatas, Centro Federal de Educacao Tecnologica do Maranhao, 65025-001 Sao Luis-MA (Brazil); Albuquerque, E.L. [Computational Physics for Engineering Materials, IfB, ETH-Zuerich, CH-8093 Zuerich (Switzerland)], E-mail: eudenilson@dfte.ufrn.br

    2009-01-19

    We study the transmission properties of light through the symmetric Fibonacci photonic multilayers, i.e, a binary one-dimensional quasiperiodic structure, made up of both positive (SiO{sub 2}) and negative refractive index materials with a mirror symmetry. These spectra are calculated by using a theoretical model based on the transfer matrix approach for normal incidence geometry, in which many perfect transmission peaks (the transmission coefficients are equal to the unity) are numerically obtained. Besides, the transmission coefficient exhibits a six-cycle self-similar behavior with respect to the generation number of the Fibonacci sequence.

  2. Precision-analog fiber-optic transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Stover, G.

    1981-06-01

    This article describes the design, experimental development, and construction of a DC-coupled precision analog fiber optic link. Topics to be covered include overall electrical and mechanical system parameters, basic circuit organization, modulation format, optical system design, optical receiver circuit analysis, and the experimental verification of the major design parameters.

  3. Optical single-sideband OFDM transmission based on a two-segment EAM.

    Science.gov (United States)

    Cheng, Hsuan-Lin; Chen, Wei-Hung; Wei, Chia-Chien; Chiu, Yi-Jen

    2015-01-26

    This paper presents a novel optical single-sideband (SSB) OFDM modulation scheme using a two-segment electro-absorption modulator (EAM). Differences in the chirp characteristics of two segments of the EAM make it possible to design driving signals capable of suppressing one of the optical sidebands, such that the optical OFDM signal does not suffer from frequency-selective power fading following dispersive fiber transmission. Our experiment results demonstrate optical OFDM transmissions at 13.5-Gbps over a 0 ∼ 200-km IM/DD system without the need for dispersion compensation and distance-dependent bit- and power-loading.

  4. Long-term stability of fibre-optic transmission for multi-object spectroscopy

    CERN Document Server

    Sharp, R; Cannon, R D

    2012-01-01

    We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from six years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope is presented. We find no evidence for significant degradation in the bulk transmission properties of the 38 m optical fibre train. Significant losses (<20% relative, 4% absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation.

  5. Demonstration of 400 Gb/s optical PDM-OFDM superchannel unrepeatered transmission by all optical phase-conjugated copy

    Science.gov (United States)

    Chen, Yuanxiang; Li, Juhao; Zhu, Paikun; Wu, Zhongying; Chen, Jingbiao; He, Yongqi; Chen, Zhangyuan

    2016-12-01

    Unrepeatered transmission delivers data over a few hundred kilometers without in-line active elements and it can effectively reduce the line complexity and the overall system cost. In this paper, we propose all optical phase-conjugated copy (OPC) to improve optical signal noise ratio (OSNR) margin and nonlinear tolerance for unrepeatered transmission of polarization division multiplexing (PDM) optical superchannel with EDFA only amplification. Orthogonal pumps FWM scheme is utilized to generate the optical phase-conjugated copy. The original superchannel and the phase-conjugated copy are simultaneously transmitted and received. The phases of the copy symbols are conjugated and summed with the original superchannel symbols to suppress both linear noise and nonlinear phase noise at the receiver. The proposed OPC scheme is simple and effective in phase-conjugated copy generation and digital signal processing (DSP). What is more, it is transparent to signal bit rate and modulation format, which applies to optical superchannel transmission. We experimentally verify the proposed scheme on a 400 Gb/s optical polarization division multiplexing orthogonal frequency division multiplexing (PDM-OFDM) superchannel. A Q-factor improvement of 2.1 dB is achieved after 180 km SSMF unrepeatered transmission. The optimum launch power in OPC scheme increases from -3 dBm to -2 dBm. To verify the maximum reach, we extend fiber length and realize 240 km SSMF unrepeatered transmission.

  6. Technologies for Compensation or Mitigation of Transmission Impairments in Future High-Speed Optical Networks

    Institute of Scientific and Technical Information of China (English)

    W.Weiershausen; S.Vorbeck

    2003-01-01

    The presentation will give an overview over different classes of signal impairments in ultra-long-haul and high-speed optical WDM transmission systems and adequate approaches for suppression, mitigation or compensation are discussed.

  7. Training-based Channel Estimation for Signal Equalization and OPM in 16-QAM Optical Transmission Systems

    DEFF Research Database (Denmark)

    Pittalà, Fabio; Hauske, Fabian N.; Ye, Yabin;

    2012-01-01

    Efficient channel estimation for signal equalization and OPM based on short CAZAC sequences with QPSK and 8PSK constellation formats is demonstrated in a 224-Gb/s PDM 16-QAM optical linear transmission system....

  8. Transmission performance of all-optically labelled packets using ASK/DPSK orthogonal modulation

    DEFF Research Database (Denmark)

    Chi, Nan; Carlsson, B.; Zhang, Jianfeng

    2002-01-01

    First transmission experiment with all-optically labelled packets consisting of ASK modulated payload and orthogonally modulated DPSK label is demonstrated. The limitation of the laser linewidth and the input extinction ratio are discussed.......First transmission experiment with all-optically labelled packets consisting of ASK modulated payload and orthogonally modulated DPSK label is demonstrated. The limitation of the laser linewidth and the input extinction ratio are discussed....

  9. Analysis of Optical Signal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.

  10. Light transmission through and its complete stoppage in an ultra slow wave optical medium

    CERN Document Server

    V., Ranjith

    2013-01-01

    Light Wave transmission -- its compression, amplification, and the optical energy storage -- in an Ultra Slow Wave Medium (USWM) is studied analytically. Our phenomenological treatment is based entirely on the continuity equation for the optical energy flux, and the well known distribution-product property of Dirac delta-function. The results so obtained provide a clear understanding of some recent experiments on light transmission and its complete stoppage in an USWM. Keywords : Ultra slow light, stopped light, slow wave medium, EIT.

  11. Transmission and transparent wavelength conversion of an optically labeled signal using ASK/DPSK orthogonal modulation

    DEFF Research Database (Denmark)

    Chi, Nan; Zhang, Jianfeng; Holm-Nielsen, Pablo Villanueva

    2003-01-01

    We report an experimental investigation of transmission and transparent wavelength conversion properties of a two-level optically labeled signal using amplitude-shift-keying/differential-phase-shift-keying orthogonal modulation. Error-free transmission of a 10-Gb/s payload and 2.5-Gb/s label over...

  12. Time-resolved optical transmission of pulsed laser-irradiated silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.C.; Lo, H.W.; Aydinli, A.; Compaan, A.

    1980-10-20

    The time-resolved optical transmission of silicon has been observed at lambda = 1.15 microns during irradiation by an 8 nsec pulsed laser at 485 nm with several energy densities in the range of .25 to 1.2 J/sq cm. The transmission exhibits a sudden brief drop consistent with the rise and fall of the reflectivity enhancement. However, the transmission does not exhibit the strong absorption expected of molten silicon with a skin depth of approx. 100A.

  13. Periodic metallic stepped-slits for entire transmission of optical wave and efficient transmission of terahertz wave

    CERN Document Server

    Khorshidi, Mohammadreza

    2016-01-01

    Metallic structures with periodic array of slits are well-known to lead to extraordinary power transmission, when slits have dimensions much less than the wavelength of incident optical wave. Excellent power transmission originates from surface waves excited by incident transverse magnetic wave. Here we show that metallic structure with array of stepped-slits can transmit power of incident wave into the substrate at desired optical frequency entirely and simultaneously in terahertz frequency band by 70%, for In0.53Ga0.47As substrate. Transmitted power of the proposed structure is studied both in a closed-form by an analytical model as well as numerically by finite element method. It is found that with the increase of field intensity in the substrate, structure with array of stepped-slits (as opposed to uniform-slits) favorably has no reduction of frequency range at maximum transmitted power.

  14. Optical and millimeter-wave radio seamless MIMO transmission based on a radio over fiber technology.

    Science.gov (United States)

    Kanno, Atsushi; Kuri, Toshiaki; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Yasumura, Yoshihiro; Kitayama, Ken-ichi

    2012-12-31

    Multi-input multi-output (MIMO) transmission of two millimeter-wave radio signals seamlessly converted from polarization-division-multiplexed quadrature-phase-shift-keying optical signals is successfully demonstrated, where a radio access unit basically consisting of only optical-to-electrical converters and a radio receiver performs total signal equalization of both the optical and the radio paths and demodulation with digital signal processing (DSP). Orthogonally polarized optical components that are directly converted to two-channel radio components can be demultiplexed and demodulated with high-speed DSP as in optical digital coherent detection. 20-Gbaud optical and radio seamless MIMO transmission provides a total capacity of 74.4 Gb/s with a forward error correction overhead of 7%.

  15. Multi-carrier transmission for hybrid radio frequency with optical wireless communications

    Science.gov (United States)

    Wang, Gang; Chen, Genshe; Shen, Dan; Pham, Khanh; Blasch, Erik; Nguyen, Tien M.

    2015-05-01

    Radio frequency (RF) wireless communication is reaching its capacity to support large data rate transmissions due to hardware constraints (e.g., silicon processes), software strategies (e.g., information theory), and consumer desire for timely large file exchanges (e.g., big data and mobile cloud computing). A high transmission rate performance must keep pace with the generated huge volumes of data for real-time processing. Integrated RF and optical wireless communications (RF/OWC) could be the next generation transmission technology to satisfy both the increased data rate exchange and the communications constraints. However, with the promising benefits of RF/OWC, challenges remain to fully develop hybrid RF with wireless optical communications such as uniform waveform design for information transmission and detection. In this paper, an orthogonal frequency division multiplexing (OFDM) transmission scheme, which widely employed in RF communications, is developed for optical communications. The traditional high peak-to-average power ratio (PAPR) in OFDM is reduced to improve system performance. The proposed multi-carrier waveform is evaluated with a frequency-selective fading channel. The results demonstrate that bit error rate (BER) performance of our proposed optical OFDM transmission technique outperforms the traditional OWC on-off keying (OOK) transmission scheme.

  16. Research on WDM optical fiber transmission system based on fiber Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    Fei Xue(薛飞); Kun Qiu(邱昆); Yue Chen(陈玥)

    2003-01-01

    After wavelength division multiplexing (WDM) optical fiber transmission system based on fiber Raman amplifier (FRA) is investigated in detail, the influence of the collocation of dispersion compensation fiber (DCF), the dispersion coefficient, dispersion slope (DS), effective core area, nonlinear index, length of FRA, launch power and the bandwidth of Bessel filter on bit error rate (BER) is deduced. The influence of Rayleigh backscattering noise on optical signal noise ratio (OSNR) is also investigated, which affects the performance of long haul transmission badly. The result indicates that the broadband long haul transmission can be realized through the reasonable design of the fiber. The result is useful to the optimal design of the WDM optical fiber transmission system based on FRA.

  17. Performing broadband optical transmission links by appropriate spectral combination of broadband SOA gain, Raman amplification and transmission fiber losses

    Science.gov (United States)

    Motaweh, T.; Sharaiha, A.; Ghisa, L.; Morel, P.; Guégan, M.; Brenot, R.; Verdier, A.

    2017-02-01

    We present the principle of a broadband optical transmission link based on the appropriate combination of the spectral profiles of broadband SOA gain, Raman amplification and transmission fiber losses. We show that, thanks to this principle, a bandwidth as wide as 89 nm (defined at -1 dB) over 75.5 km can be obtained. This bandwidth remains better than 80 nm over a wide range of optical input powers and broadband SOA bias currents, by optimizing the Raman pump. We also show theoretically that the bandwidth of our link is nearly constant for a fiber length from 25 to 100 km optimizing the SOA current. Our broadband transmission link, extended by 24.5 km of fiber, is then validated by achieving the transmission of five CWDM channels modulated at 10 Gbit/s. All five channels were transmitted over 100 km with a minimum received power sensibility of about -15.5 dBm for a reference BER of 10-3.

  18. Pulse position modulation for a subcarrier-multiplexed optical fiber transmission system

    Science.gov (United States)

    Wickramasinghe, V. R.; Ghassemlooy, Zabih F.

    1996-11-01

    Subcarrier multiplexed (SCM) optical network s offer a near to medium term alternative solution over high cost, evolving digital technology to distribute broadband services. Majority of existing systems are based on analogue optical transmission techniques and their principle disadvantage is the sensitivity to noise and system nonlinearities. Therefore, conventional SCM systems impose stringent noise and linearity requirements and as a result their performance is limited. A simple and attractive solution is to introduce an appropriate second stage modulator in order to improve the receiver sensitivity, hence the system performance.In this paper a SCM optical transmission system employing pulse position modulation as a second stage modulator, for transmission of video, audio and data channels is reported. Signal to noise ratio measurements obtained shows an improvement in optical receiver sensitivity compared with standard SCM systems.

  19. Intra-Channel Nonlinear Effect on Optical PPM Pulse Transmission

    Institute of Scientific and Technical Information of China (English)

    Sun; Linghao; Jarmo; Takala

    2003-01-01

    PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channelsystem.

  20. Experimental Investigation of WDM transmission properties for optical labeled signals using orthogonal IM/FSK modulation format

    DEFF Research Database (Denmark)

    Holm-Nielsen, Pablo Villanueva; Zhang, Jianfeng; Olmos, J. J. Vegas

    2004-01-01

    In this paper we report on WDM transmission of optical labeled signals using the orthogonal IM/FSK modulation format aimed for optical packet/burst switching. WDM transmission in both a point-to-point transmission system and a demonstration network with a label-swapping node are implemented....

  1. Gemini/GMOS Transmission Spectral Survey: Complete Optical Transmission Spectrum of the Hot Jupiter WASP-4b

    Science.gov (United States)

    Huitson, C. M.; Désert, J.-M.; Bean, J. L.; Fortney, J. J.; Stevenson, K. B.; Bergmann, M.

    2017-09-01

    We present the complete optical transmission spectrum of the hot Jupiter WASP-4b from 440 to 940 nm at R ˜ 400-1500 obtained with the Gemini Multi-Object Spectrometers (GMOS); this is the first result from a comparative exoplanetology survey program of close-in gas giants conducted with GMOS. WASP-4b has an equilibrium temperature of 1700 K and is favorable to study in transmission due to its large scale height (370 km). We derive the transmission spectrum of WASP-4b using four transits observed with the MOS technique. We demonstrate repeatable results across multiple epochs with GMOS, and derive a combined transmission spectrum at a precision about twice above photon noise, which is roughly equal to one atmospheric scale height. The transmission spectrum is well fitted with a uniform opacity as a function of wavelength. The uniform opacity and absence of a Rayleigh slope from molecular hydrogen suggest that the atmosphere is dominated by clouds with condensate grain sizes of ˜1 μm. This result is consistent with previous observations of hot Jupiters since clouds have been seen in planets with similar equilibrium temperatures to WASP-4b. We describe a custom pipeline that we have written to reduce GMOS time-series data of exoplanet transits, and present a thorough analysis of the dominant noise sources in GMOS, which primarily consist of wavelength- and time-dependent displacements of the spectra on the detector, mainly due to a lack of atmospheric dispersion correction.

  2. Optical Transmission Line For Streak Camera Measurements at Pitz

    CERN Document Server

    Bähr, J; Lüdecke, H

    2003-01-01

    The photoinjector injector test facility at DESY Zeuthen (PITZ) [1] produces electrons with a momentum of about 4 MeV/c. It is the aim to measure the temporal characteristics of the electron bunch train and single bunches with high accuracy of the order of 1 ps and less. Several types of streak cameras will be used in combination with different radiators which transform particle energy in light. The problem to be solved is the light transport over a distance of about 27 m. Basic demands to the optical system and design principles will be explained. The optical and technical solutions will be presented. The strategy of adjustment and commissioning of the optical system will be described. The system contains switchable optics to use different radiators (OTR, Cherenkov radiators). Diagnostic tools are foreseen at different positions along the optical axis. The results of different measurements in the lab and using the original system will be presented. The problems on the minimalization of the time dipersion in ...

  3. Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

    Science.gov (United States)

    Jones, L; Nellist, P D

    2014-05-01

    In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  4. Digital Photonic Receivers for Wireless and Wireline Optical Fiber Transmission Links

    DEFF Research Database (Denmark)

    Guerrero Gonzalez, Neil

    investigations on the performance of data-aided optical channel estimation based on constant-amplitude zero-autocorrelation (CAZAC) sequences for 112 Gb/s polarization-diversity coherent optical fiber transmission links. The benefits of introducing digital signal processing functions in optically envelope......This PhD thesis addresses the design and performance evaluation of digital photonic receivers in hybrid optical fiber-wireless transmission systems. The research results presented in this thesis are pioneering in two areas. First, it is shown the first experimental demonstration of automatic...... demodulation of signals with mixed modulation formats and bit rates in a single digital coherent photonic receiver. The demodulated signals were generated on baseband and optical phase-modulated (PM) radio-over-fiber (RoF) systems. Secondly, it is presented the first known analytical and numerical...

  5. Kansas Communication and Instruction System through Fiber-Optic Transmission.

    Science.gov (United States)

    Kansas State Dept. of Education, Topeka.

    Schools and communities will restructure as they move into the next decade. The success of this restructuring will be dependent upon access to and sharing of quality teaching and information through an expanded communication system. One of the major two-way interactive technologies is the fiber-optic cable: a delivery system that will provide…

  6. Optimal Crosstalk Detection and Localization Method for Optical Time Division Multiplexed Transmission Systems

    CERN Document Server

    Jedidi, A Ahmed

    2010-01-01

    All-Optical Network (AON) is a network where the user-network interface is optical and the data does undergo optical to electrical conversion within the network. AONs are attractive because they promise very high rates, flexible switching and broad application support. There are two technologies for AON: Wavelength Division Multiplexed (WDM) and Optical Time Division Multiplexed (OTDM). OTDM transmission systems are becoming increasingly important as one of the key technologies satisfying the growing demand for large capacity optical networks. Although OTDM has several advantages in terms of operation system, such as natural accommodation of higher bit rate payloads, it introduces many security vulnerabilities, which do not exist in traditional networks. One of the serious problems with OTDM is the fact that optical crosstalk is additive, and thus the aggregate effect of crosstalk over a whole all-optical network (AON) may be more nefarious than a single point of crosstalk. This is because crosstalk can sprea...

  7. A short-range optical wireless transmission method based on LED

    Science.gov (United States)

    Miao, Meiyuan; Chen, Ailin; Zhu, Mingxing; Li, Ping; Gao, Yingming; Zou, Nianyu

    2016-10-01

    As to electromagnetic wave interfere and only one to one transmission problem of Bluetooth, a short-range LED optical wireless transmission method is proposed to be complementary technology in this paper. Furthermore achieved image transmission through this method. The system makes C52 to be the mater controller, transmitter got data from terminals by USB and sends modulated signals with LED. Optical signal is detected by PD, through amplified, filtered with shaping wave from, and demodulated on receiver. Then send to terminals like PC and reverted back to original image. Analysis the performance from peak power and average power, power consumption of transmitter, relationship of bit error rate and modulation mode, and influence of ambient light, respectively. The results shows that image can be received accurately which uses this method. The most distant transmission distance can get to 1m with transmitter LED source of 1w, and the transfer rate is 14.4Kbit/s with OOK modulation mode on stabilization system, the ambient light effect little to LED transmission system in normal light environment. The method is a convenient to carry LED wireless short range transmission for mobile transmission equipment as a supplement of Bluetooth short-range transmission for its ISM band interfere, and the analysis method in this paper can be a reference for other similar systems. It also proves the system is feasibility for next study.

  8. Left-handed extraordinary optical transmission through a photonic crystal of subwavelength hole arrays.

    Science.gov (United States)

    Beruete, Miguel; Sorolla, Mario; Campillo, Igor

    2006-06-12

    Metamaterial structures are artificial materials that show unconventional electromagnetic properties such as photonic band-gap, extraordinary optical transmission and left-handed propagation. Up to now, relations of photonic crystals and negative refraction have been shown as well as of photonic crystals and sub-wavelength hole arrays. Here we report a left-handed metamaterial engineered by a combination of sub-wavelength hole array plates periodically stacked to form a photonic crystal structure. It is shown the possibility of fine-tuning the metamaterial in order to permit extraordinary optical transmission and left-handed behaviour. Our work demonstrates the feasibility of engineering left-handed metamaterials by just drilling holes in metallic plates and brings together single structure photonic crystals, extraordinary optical transmission and left-handed behaviour.

  9. Nonreciprocal optical transmission through a single conical air hole in an Ag film.

    Science.gov (United States)

    Peng, Nan; Li, Xiaokang; She, Weilong

    2014-07-14

    In this paper, we propose a simple metal micro-nano structure having the character of nonreciprocal optical zero-order transmission. The structure is a single conical air hole (CAH) in an Ag film whose optical absorption with geometric asymmetry breaks the time reversal symmetry of the electromagnetic field. By comparing the transmissions of Ag CAH with those of ideal conductor (IC) CAH, three effects of Ag CAH, including diffraction, Fabry-Perot-like (FPL) resonance and localized surface plasmon (LSP) resonance, are analyzed and discussed. Under optimized conditions, we find that the ratio of forward transmission to backward one can be larger than 9 at a proper wavelength in visible range. This kind of Ag CAH is expected to have the potential served as all-optical diode.

  10. Influence of Deviation on Optical Transmission through Aperiodic Superlattices

    Institute of Scientific and Technical Information of China (English)

    YIN Hai-Long; YANG Xiang-Bo; LAN Sheng; HU Wei

    2007-01-01

    We propose a deviation model and study the influences of the relative error and sensitivity of a machine on the transmission coefficients (TCs) of Fibonacci superlattices. It is found that for a system with fewer layers, the influence of deviation can be ignored. When superlattices become more complicated, they may be fabricated by a machine with suitable relative error and possess the designed value of TC. However, when the number of system layers exceeds some critical value, superlattices should be manufactured only by precise machines. The influence of the sensitivity is also discussed.

  11. Power transmission coefficients for multi-step index optical fibres.

    Science.gov (United States)

    Aldabaldetreku, Gotzon; Zubia, Joseba; Durana, Gaizka; Arrue, Jon

    2006-02-20

    The aim of the present paper is to provide a single analytical expression of the power transmission coefficient for leaky rays in multi-step index (MSI) fibres. This expression is valid for all tunnelling and refracting rays and allows us to evaluate numerically the power attenuation along an MSI fibre of an arbitrary number of layers. We validate our analysis by comparing the results obtained for limit cases of MSI fibres with those corresponding to step-index (SI) and graded-index (GI) fibres. We also make a similar comparison between this theoretical expression and the use of the WKB solutions of the scalar wave equation.

  12. Wideband Analog Transmission System Based on the External Intensity Electro-Optic Modulator

    Directory of Open Access Journals (Sweden)

    Jiri Svarny

    2016-01-01

    Full Text Available The work deals with design and integration of an analog electro-optic transmission system suitable for some specialized tasks of diagnostics and measurements. The system is based on principle of external intensity modulation of fiber guided laser radiation. Besides wideband and almost lossless transmission the system tolerates extreme length of the transmitting medium and ensures ultimate galvanic barrier between the input and output.

  13. An Optical Transmission Spectrum of GJ 1214b Suggesting a Heterogeneous Stellar Photosphere

    Science.gov (United States)

    Rackham, Benjamin; Espinoza, Néstor; Apai, Daniel; Lopez-Morales, Mercedes; Jordán, Andrés; Osip, David J.; Lewis, Nikole; Rodler, Florian; Fraine, Jonathan D.; Morley, Caroline; Fortney, Jonathan J.

    2016-10-01

    Measurements of the transmission spectrum of a transiting exoplanet require an understanding of the host star's photosphere. If the transit chord differs from the rest of the photosphere, as is the case when unocculted starspots are present, the difference between the two regions will be imprinted on the transmission spectrum we observe. This issue is particularly important for M-dwarf host stars, which provide the best opportunities to study smaller transiting planets, but also remain active for longer after formation than their higher-mass counterparts. Here, we present an optical transmission (4,500-9,260 Å) of the sub-Neptune GJ 1214b measured with Magellan/IMACS, which points to features potentially imprinted by its mid-M-dwarf host star. Our optical spectrum is generally offset below values found in the near-infrared for this target, and tends to decrease at shorter wavelengths. We find the ensemble of optical and near-infrared transit depths are best explained by the combination of a flat planetary transmission spectrum—owing to lofted, equilibrium condensate clouds or thick photochemical hazes—and another signal produced by heterogeneities in the stellar photosphere. We present the Composite Photosphere and Atmospheric Transmission (CPAT) model for jointly incorporating stellar and exoplanetary signals. Using the CPAT model, we show that unocculted stellar faculae with temperature contrasts and covering fractions similar to those found for solar limb faculae can explain the observed optical transmission spectrum. We show how the CPAT model can be used to correct transmission spectra for persistent heterogeneities in stellar photospheres, like limb faculae, and discuss the implications of stellar photospheric heterogeneities for transmission spectroscopy of exciting M-dwarf-hosted exoplanets that will be discovered by the Transiting Exoplanet Survey Satellite.

  14. Optical transmission versus ac magnetization measurements for monitoring colloidal Ni nanorod rotational dynamics

    Science.gov (United States)

    Gratz, M.; Tschöpe, A.

    2017-01-01

    Ni nanorods with an average length transmission of nanorod colloidal dispersions in alternating magnetic fields were measured and analyzed with the objective of comparing the intrinsic Brownian relaxation times obtained with the two methods. The different physical origin of the measured signal, related to different moments of the orientation distribution function, and the non-linear effects expected for the large magnetic moments of the Ni nanorods at common field amplitudes required a comprehensive modelling. The time-dependent magnetization and optical transmission in ac magnetic fields was derived by numerical solution of the Fokker-Planck equation. The simulated time-dependent magnetization and optical transmission at a given frequency and field amplitude were analyzed analogous to experimental data to determine characteristic relaxation frequencies. Empirical relationships were derived which enabled extraction of the intrinsic Brownian relaxation time from the characteristic frequencies measured in the non-linear regime. Despite large differences in the characteristic frequencies obtained from magnetization and optical transmission measurements, the retrieved intrinsic Brownian relaxation times were found to agree well. The potential of ac magnetic field-dependent optical transmission for biosensing applications was demonstrated by monitoring the adsorption of the protein gelatine on the nanorod labels.

  15. Polarization mode dispersion in optical fiber transmission systems

    Science.gov (United States)

    Cameron, John Charles

    The birefringence of optical fibers causes pulse broadening in fiber-optic communication systems. This phenomenon is known as polarization mode dispersion (PMD). PMD is one of the most important limiting factors for high capacity fiber-optic systems. A number of aspects of PMD are examined in this thesis. In Chapter 2 an expression is derived for the probability density function of the pulse broadening due to first-order PMD. This result is used to obtain an expression for the system limitation due to PMD. The birefringence of optical fibers is commonly simulated with the waveplate model. In Chapter 3 two standard versions of the waveplate model are introduced. In addition, a novel waveplate model is proposed. The characteristics of the three versions of the waveplate model are examined to confirm their suitability for use in subsequent chapters of the thesis. Simulations with the waveplate model are performed in Chapter 4 for three purposes: (1) to determine the impact of chromatic dispersion on the system limitation due to PMD, (2) to examine the effectiveness of three different PMD compensation techniques in the presence of chromatic dispersion, and (3) to examine the interaction of second-order chromatic dispersion with PMD. The simulations in Chapter 4 reveal that it is possible with one compensation technique to have output pulses that are narrower than the input pulses. In Chapter 5, this anomalous pulse narrowing is demonstrated analytically for a simple model of PMD and through experiment. It is also shown that this pulse narrowing can be explained as an interference phenomenon. Chapter 6 presents measurements of PMD and state of polarization on installed optical fibers. The PMD coefficients of 122 fibers are presented and the results are analyzed in terms of the age of the fibers and the type of cabling. Measurements of the time evolution of PMD and state of polarization are presented for fibers installed in both buried and aerial cables. The uncertainty

  16. Photonic Crystal Fibres as the Transmission Medium for Future Optical Communication Systems

    DEFF Research Database (Denmark)

    Zsigri, Beata

    2006-01-01

    During this Ph.D. work, air-silica photonic crystal fibres(PCFs) have been investigated for telecommunication applications. PCFs have a complicated cladding structure, where air holes, running along the entire fibre length, ensure light guidance. Photonic crystal fibres can be classified into two......, and exploited for building fully functional, entirely PCF based optical transmission links and networks. The first 40 Gbit/s transmission over 5.6 km PCF with mid-span spectral inversion dispersion compensation realised in a highly nonlinear photonic crystal fibre is demonstrated. The first optical network...

  17. 1.28 Tbaud Nyquist Signal Transmission using Time-Domain Optical Fourier Transformation based Receiver

    DEFF Research Database (Denmark)

    Hu, Hao; Kong, Deming; Palushani, Evarist

    2013-01-01

    We demonstrate transmission of a 1.28-Tbaud Nyquist-OTDM signal over a record distance of 100 km with detection by time-domain optical Fourier transformation followed by FEC decoding, resulting in error-free performance for all tributaries.......We demonstrate transmission of a 1.28-Tbaud Nyquist-OTDM signal over a record distance of 100 km with detection by time-domain optical Fourier transformation followed by FEC decoding, resulting in error-free performance for all tributaries....

  18. Single-side-band optical modulation in SCM systems for high-speed optical transmission

    Institute of Scientific and Technical Information of China (English)

    李忠义; 廖同庆

    2009-01-01

    In order to decrease dispersion penalty and increase the optical bandwidth efficiency,an optical single-side-band modulation(SSBM) scheme in sub-carrier multiplexing(SCM) is proposed.The principle of the SSBM is analytically presented,and a configuration for generating optical SSB signal is proposed using a balanced Mach-Zehnder electro-optic modulator.

  19. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin-Mok, E-mail: jmkim@kriss.re.kr; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong [Brain Cognition Measurement Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

    2013-12-15

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  20. Optical transmission modules for multi-channel superconducting quantum interference device readouts

    Science.gov (United States)

    Kim, Jin-Mok; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong

    2013-12-01

    We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

  1. Welding-fume-induced transmission loss in tapered optical fibers

    Science.gov (United States)

    Yi, Ji-Haeng

    2015-09-01

    This paper presents a method for sensing welding fumes in real time. This method is based on the results of nanoparticle-induced optical-fiber loss experiments that show that the losses are determined by the nanoparticle density and the taper waist. The tapered fiber is obtained by applying heat radiated from hot quartz, and monitoring is done in real time. First, the durability of the tapered fiber during the welding process is proven. Then, the loss is categorized by using the sizes of welding fume particles. The sensitivity to welding fumes increases with increasing size of the particles; consequently, the dimension of the taper waist decreases.

  2. Design of a fiber-optic transmitter for microwave analog transmission with high phase stability

    Science.gov (United States)

    Logan, R. T., Jr.; Lutes, G. F.; Primas, L. E.; Maleki, L.

    1990-01-01

    The principal considerations in the design of fiber-optic transmitters for highly phase-stable radio frequency and microwave analog transmission are discussed. Criteria for a fiber-optic transmitter design with improved amplitude and phase-noise performance are developed through consideration of factors affecting the phase noise, including low-frequency laser-bias supply noise, the magnitude and proximity of external reflections into the laser, and temperature excursions of the laser-transmitter package.

  3. Full-field transmission x-ray imaging with confocal polycapillary x-ray optics.

    Science.gov (United States)

    Sun, Tianxi; Macdonald, C A

    2013-02-07

    A transmission x-ray imaging setup based on a confocal combination of a polycapillary focusing x-ray optic followed by a polycapillary collimating x-ray optic was designed and demonstrated to have good resolution, better than the unmagnified pixel size and unlimited by the x-ray tube spot size. This imaging setup has potential application in x-ray imaging for small samples, for example, for histology specimens.

  4. 160 Gb/s OFDM transmission utilizing an all-optical symbol generator based on PLC

    Science.gov (United States)

    Liang, Xiaojun; Qiao, Yaojun; Li, Wei; Mei, Junyao; Qin, Yi

    2009-11-01

    We demonstrate a 160 Gb/s orthogonal frequency division multiplexing (OFDM) system using an all-optical symbol generator based on planar light circuit (PLC) technology. Excellent bit error rate (BER) is observed after long-distance transmission. The proposed symbol generator fundamentally eliminates the processing speed limits introduced by electronics and is suitable for high integration, making it physically realizable to build high-speed all-optical OFDM systems with a large number of subcarriers.

  5. Optical fiber cable for transmission of high power laser energy over great distances

    Science.gov (United States)

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Moxley, Joel F.; Koblick, Yeshaya

    2016-05-24

    There is provided a system and apparatus for the transmission of high power laser energy over great distances without substantial power loss and without the presence of stimulated Raman scattering. There is further provided systems and optical fiber cable configurations and optical fiber structures for the delivering high power laser energy over great distances to a tool or surface to perform an operation or work with the tool or upon the surface.

  6. Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.

  7. Optical fiber configurations for transmission of laser energy over great distances

    Science.gov (United States)

    Rinzler, Charles C; Zediker, Mark S

    2013-10-29

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  8. Optical fiber cable for transmission of high power laser energy over great distances

    Energy Technology Data Exchange (ETDEWEB)

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Moxley, Joel F.; Koblick, Yeshaya

    2016-05-24

    There is provided a system and apparatus for the transmission of high power laser energy over great distances without substantial power loss and without the presence of stimulated Raman scattering. There is further provided systems and optical fiber cable configurations and optical fiber structures for the delivering high power laser energy over great distances to a tool or surface to perform an operation or work with the tool or upon the surface.

  9. Optical fiber configurations for transmission of laser energy over great distances

    Energy Technology Data Exchange (ETDEWEB)

    Rinzler, Charles C; Zediker, Mark S

    2014-11-04

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  10. Generation of radially and azimuthally polarized light by optical transmission through concentric circular nanoslits in Ag films.

    Science.gov (United States)

    Wang, Feng; Xiao, Min; Sun, Kai; Wei, Qi-Huo

    2010-01-04

    Optical transmission through concentric circular nanoslits is studied in experiments and numerical simulations. Polarized optical microscopic imaging shows that the optical transmission through these apertures is spatially inhomogeneous, exhibiting colored fan texture patterns. Numerical simulations show that these colored fan texture patterns originate from the cylindrical vector polarization of the transmitted beam. Specifically, the transmitted light is in-phase radially polarized at long wavelengths due to the predominant transmission of the transverse magnetic (TM) waveguide modes; and in-phase azimuthally polarized at short wavelengths due to the increased optical transmission of the transverse electric (TE) waveguide modes. Additionally, the transmission shows a peak at the wavelength of Wood anomaly and a dip at the resonant wavelength of surface plasmon excitation; and the transmitted light at these wavelengths is a mixture of azimuthally and radially polarized fields. These interesting optical transmission behaviors of circular nanoslits provide a miniaturized way to generating radially and azimuthally polarized light.

  11. Hardware authentication using transmission spectra modified optical fiber.

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, Robert K.; Romero, Juan A.

    2010-09-01

    The ability to authenticate the source and integrity of data is critical to the monitoring and inspection of special nuclear materials, including hardware related to weapons production. Current methods rely on electronic encryption/authentication codes housed in monitoring devices. This always invites the question of implementation and protection of authentication information in an electronic component necessitating EMI shielding, possibly an on board power source to maintain the information in memory. By using atomic layer deposition techniques (ALD) on photonic band gap (PBG) optical fibers we will explore the potential to randomly manipulate the output spectrum and intensity of an input light source. This randomization could produce unique signatures authenticating devices with the potential to authenticate data. An external light source projected through the fiber with a spectrometer at the exit would 'read' the unique signature. No internal power or computational resources would be required.

  12. Plasmon resonance enhanced optical transmission and magneto-optical Faraday effects in nanohole arrays blocked by metal antenna

    Science.gov (United States)

    Lei, Chengxin; Tang, Zhixiong; Wang, Sihao; Li, Daoyong; Chen, Leyi; Tang, Shaolong; Du, Youwei

    2017-07-01

    The properties of the optical and magneto-optical effects of an improved plasmonic nanohole arrays blocked by gold mushroom caps are investigated by using the finite difference time domain (FDTD) method. It is most noteworthy that the strongly enhanced Faraday rotation along with high transmittance has been achieved simultaneously by optimizing the parameters of nanostructure in a broad spectrum spanning visible to near-infrared frequencies, which is very important in practical application for designing novel optical and magneto-optical devices. In our designed structure, we obtained two extraordinary optical transmission (EOT) resonant peaks along with enhanced Faraday rotation and two peaks of the figure of merit (FOM). By optimizing the geometrical parameters of the structure, we can obtain an almost 10-fold enhancement of Faraday rotation with a corresponding transmittance 50%, and the FOM of 0.752 at the same wavelength. As expected, the optical and magneto-optical effects sensitively depends on the geometrical parameters of our structure, which can be simply tailored by the height of pillar, the diameter of mushroom cap, and the period of the structure, and so on. The physical mechanism of these physical phenomena in the paper has been explained in detail. These research findings are of great theoretical significance in developing the novel magneto-optical devices in the future.

  13. Transcutaneous Optical Information Transmission System for a Totally Implantable Artificial Heart

    Science.gov (United States)

    Yamamoto, Takahiko; Koshiji, Kohji

    A transcutaneous optical information transmission system (TOITS) offers the most promising method for noninvasively transmitting the information to control a total artificial heart (TAH). We had used light-emitting diode (LED) and photo diode (PD) with different wavelengths for full-duplex bidirectional communication in the TOITS. In this study, reduction of optical crosstalk in full-duplex bidirectional communication was investigated by using a combination of two orthogonal polarizers with the same wavelength. As a result, we confirmed that optical crosstalk could be prevented for communication through a cow's skin (3.5 mm thick) and that the signal waveform could be transmitted satisfactorily.

  14. Experimental demonstration of optical stealth transmission over wavelength-division multiplexing network.

    Science.gov (United States)

    Zhu, Huatao; Wang, Rong; Pu, Tao; Fang, Tao; Xiang, Peng; Zheng, Jilin; Tang, Yeteng; Chen, Dalei

    2016-08-10

    We propose and experimentally demonstrate an optical stealth transmission system over a 200 GHz-grid wavelength-division multiplexing (WDM) network. The stealth signal is processed by spectral broadening, temporal spreading, and power equalizing. The public signal is suppressed by multiband notch filtering at the stealth channel receiver. The interaction between the public and stealth channels is investigated in terms of public-signal-to-stealth-signal ratio, data rate, notch-filter bandwidth, and public channel number. The stealth signal can transmit over 80 km single-mode fiber with no error. Our experimental results verify the feasibility of optical steganography used over the existing WDM-based optical network.

  15. Experimental demonstration of a cognitive quality of transmission estimator for optical communication systems

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Aguado, Juan Carlos; Borkowski, Robert;

    2012-01-01

    The impact of physical layer impairments in optical network design and operation has received significant attention in the last years, thereby requiring estimation techniques to predict the quality of transmission (QoT) of optical connections before being established. In this paper, we report...... on the experimental demonstration of a case-based reasoning (CBR) technique to predict whether optical channels fulfill QoT requirements, thus supporting impairment-aware networking. The validation of the cognitive QoT estimator is performed in a WDM 80 Gb/s PDM-QPSK testbed, and we demonstrate that even with a very...

  16. Power-efficient method for IM-DD optical transmission of multiple OFDM signals.

    Science.gov (United States)

    Effenberger, Frank; Liu, Xiang

    2015-05-18

    We propose a power-efficient method for transmitting multiple frequency-division multiplexed (FDM) orthogonal frequency-division multiplexing (OFDM) signals in intensity-modulation direct-detection (IM-DD) optical systems. This method is based on quadratic soft clipping in combination with odd-only channel mapping. We show, both analytically and experimentally, that the proposed approach is capable of improving the power efficiency by about 3 dB as compared to conventional FDM OFDM signals under practical bias conditions, making it a viable solution in applications such as optical fiber-wireless integrated systems where both IM-DD optical transmission and OFDM signaling are important.

  17. Experimental Demonstration of a Cognitive Quality of Transmission Estimator for Optical Communication Systems

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Aguado, Juan Carlos; Borkowski, Robert;

    2012-01-01

    We report on the experimental performance of a case-based reasoning technique to predict whether optical channels fulfill quality of transmission requirements, thus supporting impairment-aware networking. Validation is performed in a WDM 80 Gb/s PDM-QPSK testbed....

  18. Atmospheric transmission at ~1.55 μm for free-space optical communication

    Science.gov (United States)

    Zeller, John; Manzur, Tariq

    2010-04-01

    Free-space optics (FSO) holds the potential for high bandwidth communication, but atmospheric conditions can significantly affect the capability of a communication system to transfer information successfully. The effects of atmosphere on FSO communication and consequent optimal wavelength range for transmission are investigated through MODTRAN-based modeling of 1.55 μm transmission for multiple elevation angles in atmospheric conditions including clear maritime, desert extinction, and various levels of rain and fog. Beam transmission was also simulated for different relevant elevations for surface-to-surface and surface-to-air free-space optical communication networks. The atmospheric, free-space, and scintillation losses are investigated for optical path lengths of 2 km to determine transmit power required for successful data reception. In addition, FSO transmitter and receiver circuits were designed to optically relay an analog video signal and tested at path distances of up to 130 m. Using advanced tunable laser sources to provide illumination across wavelength ranges, particularly around the eye-safe 1.55 μm wavelength, it should be possible to overcome transmission limitations associated with adverse weather and atmospheric conditions.

  19. Coherent optical DFT-spread OFDM transmission using orthogonal band multiplexing.

    Science.gov (United States)

    Yang, Qi; He, Zhixue; Yang, Zhu; Yu, Shaohua; Yi, Xingwen; Shieh, William

    2012-01-30

    Coherent optical OFDM (CO-OFDM) combined with orthogonal band multiplexing provides a scalable and flexible solution for achieving ultra high-speed rate. Among many CO-OFDM implementations, digital Fourier transform spread (DFT-S) CO-OFDM is proposed to mitigate fiber nonlinearity in long-haul transmission. In this paper, we first illustrate the principle of DFT-S OFDM. We then experimentally evaluate the performance of coherent optical DFT-S OFDM in a band-multiplexed transmission system. Compared with conventional clipping methods, DFT-S OFDM can reduce the OFDM peak-to-average power ratio (PAPR) value without suffering from the interference of the neighboring bands. With the benefit of much reduced PAPR, we successfully demonstrate 1.45 Tb/s DFT-S OFDM over 480 km SSMF transmission.

  20. 38.2-Gb/s Optical-Wireless Transmission in 75-110 GHz Based on Electrical OFDM with Optical Comb Expansion

    DEFF Research Database (Denmark)

    Deng, Lei; Pang, Xiaodan; Beltrán, Marta

    2012-01-01

    We demonstrate scalable optical comb- and heterodyning-based generation, optical and 1.3-m wireless transmission, and electrical heterodyne detection of multiband OFDM up to 38.2 Gb/s occupying 14.4-GHz RF bandwidth, for high-capacity optical-wireless links in 75-110 GHz.......We demonstrate scalable optical comb- and heterodyning-based generation, optical and 1.3-m wireless transmission, and electrical heterodyne detection of multiband OFDM up to 38.2 Gb/s occupying 14.4-GHz RF bandwidth, for high-capacity optical-wireless links in 75-110 GHz....

  1. Experiment on 60-GHz MMW transmission performance in an optical fiber and wireless system

    Institute of Scientific and Technical Information of China (English)

    Qi Tang; Lin Chen; Jiangnan Xiao; Zizheng Cao

    2011-01-01

    We experimentally investigate the transmission performance of 60-GHz signals over standard single-mode fiber (SSMF) and wireless links at different bit rates.Experimental results show that in a transmission of over 10-km SSMF and 1.3-m wireless link, bit rate reaches up to 5 Gb/s and bit error rate (BER) is leas than 10-4.The main limiting factor in such radio-over-fiber (ROF) systems is intersymbol interferences caused by the so-called walk-off effect when BER is below 10-8.In addition, a transmission of over 20-km SSMF without chromatic dispersion compensation is briefly investigated.For a BER of 10-8, the optical penalty is 2 dB.%@@ We experimentally investigate the transmission performance of 60-GHz signals over standard single-mode fiber (SSMF) and wireless links at different bit rates.Experimental results show that in a transmission of over 10-km SSMF and 1.3-m wireless link, bit rate reaches up to 5 Gb/s and bit error rate (BER) is less than 10-4.The main limiting factor in such radio-over-fiber (ROF) systems is intersymbol interferences caused by the so-called walk-off effect when BER is below 10-8.In addition, a transmission of over 20-km SSMF without chromatic dispersion compensation is briefly investigated.For a BER of 10-s, the optical penalty is 2 dB.

  2. Simulation and Noise Analysis of Multimedia Transmission in Optical CDMA Computer Networks

    Directory of Open Access Journals (Sweden)

    Nasaruddin

    2009-11-01

    Full Text Available This paper simulates and analyzes noise of multimedia transmission in a flexible optical code division multiple access (OCDMA computer network with different quality of service (QoS requirements. To achieve multimedia transmission in OCDMA, we have proposed strict variable-weight optical orthogonal codes (VW-OOCs, which can guarantee the smallest correlation value of one by the optimal design. In developing multimedia transmission for computer network, a simulation tool is essential in analyzing the effectiveness of various transmissions of services. In this paper, implementation models are proposed to analyze the multimedia transmission in the representative of OCDMA computer networks by using MATLAB simulink tools. Simulation results of the models are discussed including spectrums outputs of transmitted signals, superimposed signals, received signals, and eye diagrams with and without noise. Using the proposed models, multimedia OCDMA computer network using the strict VW-OOC is practically evaluated. Furthermore, system performance is also evaluated by considering avalanche photodiode (APD noise and thermal noise. The results show that the system performance depends on code weight, received laser power, APD noise, and thermal noise which should be considered as important parameters to design and implement multimedia transmission in OCDMA computer networks.

  3. Simulation and Noise Analysis of Multimedia Transmission in Optical CDMA Computer Networks

    Directory of Open Access Journals (Sweden)

    Nasaruddin Nasaruddin

    2013-09-01

    Full Text Available This paper simulates and analyzes noise of multimedia transmission in a flexible optical code division multiple access (OCDMA computer network with different quality of service (QoS requirements. To achieve multimedia transmission in OCDMA, we have proposed strict variable-weight optical orthogonal codes (VW-OOCs, which can guarantee the smallest correlation value of one by the optimal design. In developing multimedia transmission for computer network, a simulation tool is essential in analyzing the effectiveness of various transmissions of services. In this paper, implementation models are proposed to analyze the multimedia transmission in the representative of OCDMA computer networks by using MATLAB simulink tools. Simulation results of the models are discussed including spectrums outputs of transmitted signals, superimposed signals, received signals, and eye diagrams with and without noise. Using the proposed models, multimedia OCDMA computer network using the strict VW-OOC is practically evaluated. Furthermore, system performance is also evaluated by considering avalanche photodiode (APD noise and thermal noise. The results show that the system performance depends on code weight, received laser power, APD noise, and thermal noise which should be considered as important parameters to design and implement multimedia transmission in OCDMA computer networks.

  4. Fibre Optic Bus Network For Voice And Data Transmission In A Ship

    Science.gov (United States)

    Jhunjhunwala, Ashok; Sanghi, R. K.; Manjunath, D.

    1987-12-01

    A versatile communication system in a ship with 120 stations, each having voice and data transmission is envisaged. The proposed fibre optic network has a bus topology ideally suited for distribution in ship-like environment. Use has been made of standard ETHERNET chip sets manufactured by INTEL. This makes the stations compact, easier to maintain and inexpensive. The ETHERNET proto-col is primarily designed for packet data transmission. The collision detection and backoff protocol makes the packet transmission probabilistic and is therefore not suitable for voice transmission. This problem is overcome in the present design by a scheme where the required number of voice slots are dynamically allocated. That is, having established a connection for voice communication between stations, fixed slots are assigned for voice transmission and reception. The data transmission continues to use CSMA/CD Protocol. A simple hardware addition to the ETHERNET chip set makes the scheme workable. Drops in the fiber optic bus network is through passive star couplers. Four to eight star couplers are used in the present scheme with repeaters between adjacent star couplers. The repeaters will not be usual repeaters, as ordinary repeaters would cause loops to be formed between adjacent stars, thereby causing data to recirculate. This recirculation is avoided by making the repeater intelligent and also performing the task of detecting collisions between signals originating from stations connected to different star couplers.

  5. On-chip passive three-port circuit of all-optical ordered-route transmission

    Science.gov (United States)

    Liu, Li; Dong, Jianji; Gao, Dingshan; Zheng, Aoling; Zhang, Xinliang

    2015-05-01

    On-chip photonic circuits of different specific functions are highly desirable and becoming significant demands in all-optical communication network. Especially, the function to control the transmission directions of the optical signals in integrated circuits is a fundamental research. Previous schemes, such as on-chip optical circulators, are mostly realized by Faraday effect which suffers from material incompatibilities between semiconductors and magneto-optical materials. Achieving highly functional circuits in which light circulates in a particular direction with satisfied performances are still difficult in pure silicon photonics platform. Here, we propose and experimentally demonstrate a three-port passive device supporting optical ordered-route transmission based on silicon thermo-optic effect for the first time. By injecting strong power from only one port, the light could transmit through the three ports in a strict order (1→2, 2→3, 3→1) while be blocked in the opposite order (1→3, 3→2, 2→1). The blocking extinction ratios and operation bandwidths have been investigated in this paper. Moreover, with compact size, economic fabrication process and great extensibility, this proposed photonic integrated circuit is competitive to be applied in on-chip all-optical information processing systems, such as path priority selector.

  6. Analysis of the static magnetic field-dependent optical transmission of Ni nanorod colloidal suspensions

    Science.gov (United States)

    Krämer, Florian; Gratz, Micha; Tschöpe, Andreas

    2016-07-01

    The magnetic field-dependent optical transmission of dilute Ni nanorod aqueous suspensions was investigated. A series of four samples of nanorods were synthesized using the AAO template method and processed to stable colloids. The distributions of their length and diameter were characterized by analysis of TEM images and revealed average diameters of ˜25 nm and different lengths in the range of 60 nm-1100 nm. The collinear magnetic and optical anisotropy was studied by static field-dependent transmission measurements of linearly polarized light parallel and perpendicular to the magnetic field direction. The experimental results were modelled assuming the field-dependent orientation distribution function of a superparamagnetic ensemble for the uniaxial ferromagnetic nanorods in liquid dispersion and extinction cross sections for longitudinal and transversal optical polarization derived from different approaches, including the electrostatic approximation and the separation of variables method, both applied to spheroidal particles, as well as finite element method simulations of spheroids and capped cylindrical particles. The extinction cross sections were compared to reveal the differences associated with the approximations of homogeneous polarization and/or particle shape. The consequences of these approximations for the quantitative analysis of magnetic field-dependent optical transmission measurements were investigated and a reliable protocol derived. Furthermore, the changes in optical cross sections induced by electromagnetic interaction between two nanorods in parallel end-to-end and side-by-side configuration as a function of their separation were studied.

  7. An Exploration of Professional Culture Differentials and Their Potential Impact on the Information Assurance Component of Optical Transmission Networks Design

    Science.gov (United States)

    Cuthrell, Michael Gerard

    2011-01-01

    Optical transmission networks are an integral component of the critical infrastructures for many nations. Many people believe that optical transmission networks are impenetrable. In actuality, these networks possess weaknesses that can be exploited to bring about harm. An emerging Information Assurance (IA) industry has as its goals: to…

  8. SOA - NOLM in Reflective Configuration for Optical Regeneration in High Bit Rate Transmission Systems

    CERN Document Server

    Roncin, Vincent; Gay, Mathilde; Bramerie, Laurent; Simon, Jean-Claude

    2014-01-01

    This paper presents a theoretical and experimental investigation of optical signal regeneration properties of a non-linear optical loop mirror using a semiconductor optical amplifier as the active element (SOA-NOLM). While this device has been extensively studied for optical time division demultiplexing (OTDM) and wavelength conversion applications, our proposed approach, based on a reflective configuration, has not yet been investigated, particularly in the light of signal regeneration. The impact on the transfer function shape of different parameters, like SOA position in the interferometer and SOA input optical powers, are numerically studied to appreciate the regenerative capabilities of the device.Regenerative performances in association with a dual stage of SOA to create a 3R regenerator which preserves the data polarity and the wavelength are experimentally assessed. Thanks to this complete regenerative function, a 100.000 km error free transmission has experimentally been achieved at 10 Gb/s in a reci...

  9. Optical differential phase-shift keyed signal generation, transmission and detection

    Science.gov (United States)

    Lize, Yannick Keith

    When encoding information on an electromagnetic wave such as infrared light, to be transmitted through an optical fibre in telecommunication networks, any of the physical properties of light can be modulated. Light has a frequency, intensity, polarization and a phase. Until recently, optical communication systems strictly employed conventional intensity (IM) modulation signals in either non return-to-zero (NRZ) or return-to-zero (RZ) format. But a number of advanced optical modulation formats have attracted increasing attention in the last few years. One prime example is the phase-shift-keyed (PSK) family of formats which carry the information on the optical phase. Since absolute phase is not easily detected through coherent demodulation, differential encoding in which the phase of the preceding bit is used as a relative phase reference for demodulation has become a method of choice for phase modulated signals. The result in the differential-phase-shift-keyed (DPSK) formats, which carry the information in the difference in optical phase between successive bits. In this thesis by article, composed of six papers, we investigate the generation, transmission and demodulation of DPSK in optical fibre transmission systems. We propose a novel way to encode optical packets using DPSK in our investigation of the generation. We also investigate transmission effects monitoring using a novel partial-bit delay interferometer-assisted clock tone monitoring method for sensitive optical-signal-to-noise ratio (OSNR), chromatic dispersion and polarization mode dispersion monitoring. Then we look at the demodulation of DPSK, first investigating the reduced tolerances and power penalties of DPSK demodulation when more than one bit delay is used in the interferometer. We also propose an optical error correction method combining DPSK optical logic gates with electronic logic gates to improve receiver sensitivity and transmission impairment tolerances. Finally we redefine the previously

  10. Achieving High-Frequency Optical Control of Synaptic Transmission

    Science.gov (United States)

    Jackman, Skyler L.; Beneduce, Brandon M.; Drew, Iain R.

    2014-01-01

    The optogenetic tool channelrhodopsin-2 (ChR2) is widely used to excite neurons to study neural circuits. Previous optogenetic studies of synapses suggest that light-evoked synaptic responses often exhibit artificial synaptic depression, which has been attributed to either the inability of ChR2 to reliably fire presynaptic axons or to ChR2 elevating the probability of release by depolarizing presynaptic boutons. Here, we compare light-evoked and electrically evoked synaptic responses for high-frequency stimulation at three synapses in the mouse brain. At synapses from Purkinje cells to deep cerebellar nuclei neurons (PC→DCN), light- and electrically evoked synaptic currents were remarkably similar for ChR2 expressed transgenically or with adeno-associated virus (AAV) expression vectors. For hippocampal CA3→CA1 synapses, AAV expression vectors of serotype 1, 5, and 8 led to light-evoked synaptic currents that depressed much more than electrically evoked currents, even though ChR2 could fire axons reliably at up to 50 Hz. The disparity between optical and electrical stimulation was eliminated when ChR2 was expressed transgenically or with AAV9. For cerebellar granule cell to stellate cell (grc→SC) synapses, AAV1 also led to artificial synaptic depression and AAV9 provided superior performance. Artificial synaptic depression also occurred when stimulating over presynaptic boutons, rather than axons, at CA3→CA1 synapses, but not at PC→DCN synapses. These findings indicate that ChR2 expression methods and light stimulation techniques influence synaptic responses in a neuron-specific manner. They also identify pitfalls associated with using ChR2 to study synapses and suggest an approach that allows optogenetics to be applied in a manner that helps to avoid potential complications. PMID:24872574

  11. Enhanced extraordinary optical transmission (EOT) through arrays of bridged nanohole pairs and their sensing applications

    KAUST Repository

    Yue, Weisheng

    2014-01-01

    Extraordinary optical transmission (EOT) through arrays of gold nanoholes was studied with light across the visible to the near-infrared spectrum. The EOT effect was found to be improved by bridging pairs of nanoholes due to the concentration of the electromagnetic field in the slit between the holes. The geometrical shape and separation of the holes in these pairs of nanoholes affected the intensity of the transmission and the wavelength of resonance. Changing the geometrical shapes of these nanohole pairs from triangles to circles to squares leads to increased transmission intensity as well as red-shifting resonance wavelengths. The performance of bridged nanohole pairs as a plasmonic sensor was investigated. The bridged nanohole pairs were able to distinguish methanol, olive oil and microscope immersion oil for the different surface plasmon resonance in transmission spectra. Numerical simulation results were in agreement with experimental observations. © 2014 the Partner Organisations.

  12. ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere

    Science.gov (United States)

    Rackham, Benjamin; Espinoza, Néstor; Apai, Dániel; López-Morales, Mercedes; Jordán, Andrés; Osip, David J.; Lewis, Nikole K.; Rodler, Florian; Fraine, Jonathan D.; Morley, Caroline V.; Fortney, Jonathan J.

    2017-01-01

    GJ 1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanet's atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum (4500–9260 Å) of GJ 1214b in 14 bins, measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of {R}p/{R}s=0.1146+/- 2× {10}-4 and mean uncertainty of σ ({R}p/{R}s)=8.7× {10}-4 in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission through the exoplanet's limb (the CPAT model), and use it to examine the cases of absorber and temperature heterogeneities in the stellar photosphere. We find the optical and near-infrared measurements are best explained by the combination of (1) photochemical haze in the exoplanetary atmosphere with a mode particle size r = 0.1 μm and haze-forming efficiency {f}{haze}=10 % and (2) faculae in the unocculted stellar disk with a temperature contrast {{Δ }}T={354}-46+46 K, assuming 3.2% surface coverage. The CPAT model can be used to assess potential contributions of heterogeneous stellar photospheres to observations of exoplanet transmission spectra, which will be important for searches for spectral features in the optical.

  13. Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

    Science.gov (United States)

    Prasad, Narasimha S.; Kratovil, Pat; Magee, James R.

    2002-04-01

    In this paper, image transmission using a mid-wave IR (MWIR) optical transceiver based free-space data link under low visibility conditions is presented. The all-solid-state MWIR transceiver primarily consisted of a passively Q-switched, short-pulsed Nd:YAG laser pumping a periodically poled lithium niobate (PPLN) based optical parametric oscillator and a Dember effect detector. The MILES transceiver generates pulse position waveforms. The optical data link consisting of transmitter drive electronics, pulse conditioning electronics and a computer generating pulses compatible with the 2400-baud rate RS232 receiver was utilized. Data formatting and RS232 transmission and reception were achieved using a computer. Data formatting transformed an arbitrary image file format compatible with the basic operation of pump laser. Images were transmitted at a date rate of 2400 kbits/sec with 16 bits/pixel. Test images consisting of 50X40 pixels and 100X80 pixels were transmitted through free-space filled with light fog up to 120 ft. Besides optical parametric oscillators, the proposed concept can be extended to optical parametric amplifiers, Raman lasers and other nonlinear optical devices to achieve multi-functionality.

  14. Optical Frequency Upconversion Technique for Transmission of Wireless MIMO-Type Signals over Optical Fiber

    OpenAIRE

    R. Q. Shaddad; Mohammad, A. B.; S. A. Al-Gailani; Al-Hetar, A. M.

    2014-01-01

    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the n...

  15. Optical Frequency Upconversion Technique for Transmission of Wireless MIMO-Type Signals over Optical Fiber

    Directory of Open Access Journals (Sweden)

    R. Q. Shaddad

    2014-01-01

    Full Text Available The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO signals feeding multiple antennas in the fiber wireless (FiWi system. A novel optical frequency upconversion (OFU technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF. The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM. The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength.

  16. Optical frequency upconversion technique for transmission of wireless MIMO-type signals over optical fiber.

    Science.gov (United States)

    Shaddad, R Q; Mohammad, A B; Al-Gailani, S A; Al-Hetar, A M

    2014-01-01

    The optical fiber is well adapted to pass multiple wireless signals having different carrier frequencies by using radio-over-fiber (ROF) technique. However, multiple wireless signals which have the same carrier frequency cannot propagate over a single optical fiber, such as wireless multi-input multi-output (MIMO) signals feeding multiple antennas in the fiber wireless (FiWi) system. A novel optical frequency upconversion (OFU) technique is proposed to solve this problem. In this paper, the novel OFU approach is used to transmit three wireless MIMO signals over a 20 km standard single mode fiber (SMF). The OFU technique exploits one optical source to produce multiple wavelengths by delivering it to a LiNbO3 external optical modulator. The wireless MIMO signals are then modulated by LiNbO3 optical intensity modulators separately using the generated optical carriers from the OFU process. These modulators use the optical single-sideband with carrier (OSSB+C) modulation scheme to optimize the system performance against the fiber dispersion effect. Each wireless MIMO signal is with a 2.4 GHz or 5 GHz carrier frequency, 1 Gb/s data rate, and 16-quadrature amplitude modulation (QAM). The crosstalk between the wireless MIMO signals is highly suppressed, since each wireless MIMO signal is carried on a specific optical wavelength.

  17. ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere

    CERN Document Server

    Rackham, Benjamin; Apai, Dániel; López-Morales, Mercedes; Jordán, Andrés; Osip, David J; Lewis, Nikole K; Rodler, Florian; Fraine, Jonathan D; Morley, Caroline V; Fortney, Jonathan J

    2016-01-01

    GJ 1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanet's atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum ($4,500-9,260$\\AA) of GJ 1214b in 14 bins measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of ${R_{p}/R_{s} = 0.1146\\pm{2\\times10^{-4}}}$ and mean uncertainty of $\\sigma(R_{p}/R_{s})=8.7\\times10^{-4}$ in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission (CPAT) through the exoplanet's limb, and use it to exa...

  18. Thermal and Transmission Properties of UV Nonlinear Optical Material-- ZnCd(SCN)4 Crystal

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Zinc cadmium thiocyanate(ZCTC), ZnCd(SCN)4, has been discovered as a UV second-order nonlinear optical coordination crystal. Its thermal and transmission properties are reported. The thermal decomposition is characterized by using the X-ray powder diffraction (XRPD) and infrared (IR) spectroscopy at room temperature. The absorptions of intrinsic ions and ZCTC in a solution state are discussed as well as transmission properties of the ZCTC crystal. An effective method of reducing the surface reflection loss of ZCTC crystal is introduced.

  19. On the optical stability of high-resolution transmission electron microscopes.

    Science.gov (United States)

    Barthel, J; Thust, A

    2013-11-01

    In the recent two decades the technique of high-resolution transmission electron microscopy experienced an unprecedented progress through the introduction of hardware aberration correctors and by the improvement of the achievable resolution to the sub-Ångström level. The important aspect that aberration correction at a given resolution requires also a well defined amount of optical stability has received little attention so far. Therefore we investigate the qualification of a variety of high-resolution electron microscopes to maintain an aberration corrected optical state in terms of an optical lifetime. We develop a comprehensive statistical framework for the estimation of the optical lifetime and find remarkably low values between tens of seconds and a couple of minutes. Probability curves are introduced, which inform the operator about the chance to work still in the fully aberration corrected state.

  20. Capacity estimates for optical transmission based on the nonlinear Fourier transform

    Science.gov (United States)

    Derevyanko, Stanislav A.; Prilepsky, Jaroslaw E.; Turitsyn, Sergei K.

    2016-09-01

    What is the maximum rate at which information can be transmitted error-free in fibre-optic communication systems? For linear channels, this was established in classic works of Nyquist and Shannon. However, despite the immense practical importance of fibre-optic communications providing for >99% of global data traffic, the channel capacity of optical links remains unknown due to the complexity introduced by fibre nonlinearity. Recently, there has been a flurry of studies examining an expected cap that nonlinearity puts on the information-carrying capacity of fibre-optic systems. Mastering the nonlinear channels requires paradigm shift from current modulation, coding and transmission techniques originally developed for linear communication systems. Here we demonstrate that using the integrability of the master model and the nonlinear Fourier transform, the lower bound on the capacity per symbol can be estimated as 10.7 bits per symbol with 500 GHz bandwidth over 2,000 km.

  1. Multi-band radio over fiber system with all-optical halfwave rectification, transmission and frequency down-conversion

    DEFF Research Database (Denmark)

    Prince, Kamau; Tafur Monroy, Idelfonso

    2011-01-01

    We introduce a novel application of all-optical half-wave rectification in the transportation and delivery of multi-frequency radio-over fiber signals. System evaluation was performed of transmission over various optical fiber types and all-optical envelope detection was implemented to achieve...

  2. Transmission of solar radiation through optical fiber and application to solar beam excited laser

    Energy Technology Data Exchange (ETDEWEB)

    Arashi, Haruo; Kaimai, Atsushi; Ishigame, Mareo

    1987-12-01

    This paper describes the transmission of high density solar radiation through optical fiber and application to a solar beam excited laser. Input solar beam, rendered a high density through a solar collector, is transmitted through optical fiber, and is separated into several fluxes. The fluxes of light are introduced into the side of a cylindrical laser mirror, where the optical fibres are made up into a rectangular form. The transmitted beam, passing through a side slit, excites a rod positioned at the centre of the laser. The separation of a solar collecting and an oscillating portion serves to increase the degree of freedom. The core of the optical fiber is composed of quartz, and a polymer cladding type having a large number of apertures. The input end of the fiber is a heat resistant air-cladding type. The fibre has a transmission of 93%, which is satisfactory for use. The optical excitation system is composed of, in combination, an elliptically cylindrical laser mirror and a cylindrical laser mirror, both of which have an internal surface gold-plated throughout. The output beam from the fiber is multiple-refracted to excite the laser efficiently. When laser beam with low intensity excited by a lamp is made to pass through a crystal of the above excitation system, the intensity is amplified. It is planned that direct laser oscillation is realized by increase of solar radiation intensity. (9 figs, 5 refs)

  3. Acoustically tuneable optical transmission through a subwavelength hole with a bubble

    CERN Document Server

    Maksymov, Ivan S

    2016-01-01

    Efficient manipulation of light with sound in subwavelength-sized volumes is important for applications in photonics, phononics and biophysics, but remains elusive. We theoretically demonstrate the control of light with MHz-range ultrasound in a subwavelength, 300 nm wide water-filled hole with a 100 nm radius air bubble. Ultrasound-driven pulsations of the bubble modulate the effective refractive index of the hole aperture, which gives rise to spectral tuning of light transmission through the hole. This control mechanism opens up novel opportunities for tuneable acousto-optic and optomechanical metamaterials, and all-optical ultrasound transduction.

  4. Optical Transmission and Morphology of Ge-Te-In Glass System

    Science.gov (United States)

    George, Achamma; Sushama, D.

    2011-10-01

    Optical studies are performed to calculate the refractive index (n), extinction coefficient (k) and dielectric constant (real and imaginary) of Ge20Te80 and Ge20Te74In6 chalcogenide glasses using transmission spectrum in the wave length range 350nm-1050nm. The surface morphology of the glasses are studied using scanning electron microscopy and the optical band gap energy (Eg) is estimated from the absorption coefficient values using Tauc's procedure. The variation of refractive index, extinction coefficient and real and imaginary parts of the dielectric constant with photon energy are also investigated using Swanepoel's method.

  5. Multi-Hop Free Space Optical Communications Using Serial Decode-and-Forward Relay Transmissions

    Institute of Scientific and Technical Information of China (English)

    Wang Junbo; Jiao Yuan; Chen Ming; Wang Jinyuan; Cao Zhe

    2011-01-01

    This paper investigates the performance of multi-hop Free Space Optical (FSO) communications using serial Decode-and-Forward (DF) relay transmissions.A statistical model for the optical intensity fluctuation at the receiver due to the combined effects of atmospheric turbulence-induced fading,misalignment fading and pass-loss is presented.Under given weather and misalignment conditions,a closed-form analytical expression for the end-to-end outage probability of serial Decode-and-Forward (DF) multi-hop FSO communications is derived.Numerical results show that the serial DF multi-hop transmission is a promising technology to enhance the performance of FSO communications.Moreover,the derived analytical expression can provide close approximations to the simulation results.

  6. Microfluidic refractometer with integrated optical fibers and end-facet transmission gratings.

    Science.gov (United States)

    Lei, Lei; Li, Hao; Shi, Jian; Chen, Yong

    2010-02-01

    We demonstrated a microfluidic refractometer with an integrated high resolution transmission grating. This grating was fabricated by UV nanoimprinting on the end facet of a multimode optical fiber which was then placed in the plan of the microfluidic device and perpendicular to a microchannel. On the opposite side of the channel, three cleaved optical fibers were added for the light collection of the zeroth and the +/- first diffraction orders. A white light source was used for illumination and the diffraction beams were analyzed with a minispectrometer. The transmission grating was merged in the sample solution of the channel, providing a refractive index-dependent diffraction efficiency. As expected, the diffraction efficiency of the zeroth and the +/- first diffraction orders are different, both being reliable for the refractive index monitoring. Such a white source and multibeam diffraction analysis also allows monitoring the sample absorption or fluorescence, thereby providing a more accurate determination of the sample refraction index.

  7. Optical and electrical enhancement of the propagation time in superconducting transmission lines

    CERN Document Server

    Cho, S H

    2000-01-01

    optical pulse energy and current controlled delays in the propagation time of electrical picosecond pulses in YBa sub 2 Cu sub 3 O sub 7 sub - sub x (YBCO) superconducting transmission lines have been investigated by using picosecond optoelectronic techniques. Electrical pulses, generated using silicon-on-sapphire photoconductive switches driven by a mode-locked Nd:YAG pumped dye laser, are propagated on superconducting transmission lines. The lines are patterned in the geometry of a microstrip and illuminated by the frequency-doubled output of an Nd:YAG laser. The measured propagation time shows a squared dependence on the optical pulse energy. For the applied current dependence, the delay through the line is tuned by 16 psec by varying the bias from zero to 190 mA. The results are in good agreement with the Ginzburg-Landau theory for the case of a uniform current density through a thin film.

  8. APPLIED OPTICS. Overcoming Kerr-induced capacity limit in optical fiber transmission.

    Science.gov (United States)

    Temprana, E; Myslivets, E; Kuo, B P-P; Liu, L; Ataie, V; Alic, N; Radic, S

    2015-06-26

    Nonlinear optical response of silica imposes a fundamental limit on the information transfer capacity in optical fibers. Communication beyond this limit requires higher signal power and suppression of nonlinear distortions to prevent irreversible information loss. The nonlinear interaction in silica is a deterministic phenomenon that can, in principle, be completely reversed. However, attempts to remove the effects of nonlinear propagation have led to only modest improvements, and the precise physical mechanism preventing nonlinear cancellation remains unknown. We demonstrate that optical carrier stability plays a critical role in canceling Kerr-induced distortions and that nonlinear wave interaction in silica can be substantially reverted if optical carriers possess a sufficient degree of mutual coherence. These measurements indicate that fiber information capacity can be notably increased over previous estimates.

  9. [Correction of light refraction and reflection in medical transmission optical tomography].

    Science.gov (United States)

    Tereshchenko, S A; Potapov, D A

    2002-01-01

    The effects of light refraction and reflection on the quality of image reconstruction in medical transmission optical tomography of high-scattering media are considered. It has been first noted that light refraction not only distorts the geometric scheme of measurements, but may lead to the appearance of object areas that cannot be scanned. Some ways of decreasing the effect of refraction on the reconstruction of spatial distribution of the extinction coefficient are stated.

  10. A microscopic T-violating optical potential implications for neutron-transmission experiments

    CERN Document Server

    Engel, J; Hnizdo, V

    1994-01-01

    We derive a T-violating P-conserving optical potential for neutron-nucleus scattering, starting from a uniquely determined two-body \\rho-exchange interaction with the same symmetry. We then obtain limits on the T-violating \\rho-nucleon coupling \\overline{g}_{\\rho} from neutron-transmission experiments in ^{165}Ho. The limits may soon compete with those from measurements of atomic electric-dipole moments.

  11. 10Gb/s Bang-Bang Clock and Data Recovery (CDR for optical transmission systems

    Directory of Open Access Journals (Sweden)

    N. Dodel

    2005-01-01

    Full Text Available A Bang-Bang Clock-Data Recovery (CDR for 10Gb/s optical transmission systems is presented. A direct modulated architecture is used for the design. Its loop characteristics can be derived using an analogy to Σ Δ theory. The circuit was produced and measured in a commercial 0.25μm BiCMOS technology with a transition frequency fT70=GHz.

  12. 10Gb/s Bang-Bang Clock and Data Recovery (CDR) for optical transmission systems

    OpenAIRE

    N. Dodel; Klar, H.

    2005-01-01

    A Bang-Bang Clock-Data Recovery (CDR) for 10Gb/s optical transmission systems is presented. A direct modulated architecture is used for the design. Its loop characteristics can be derived using an analogy to Σ Δ theory. The circuit was produced and measured in a commercial 0.25μm BiCMOS technology with a transition frequency fT70=GHz.

  13. Nanosecond optical transmission studies of laser annealing in ion-implanted silicon-on-sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.C.; Lo, H.W.; Aydinli, A.; Trott, G.J.; Compaan, A. (Kansas State Univ., Manhattan (USA). Dept. of Physics); Hale, E.B. (Missouri Univ., Rolla (USA). Dept. of Physics)

    1983-06-01

    Time-resolved optical transmission has been studied using 633 and 514 nm CW probes on ion-implantation-amorphized silicon-on-sapphire during annealing by a 10 nsec, approximately 1 J/cm/sup 2/ pulse at either 532 nm or 485 nm. As recrystallization sets in the transmitted signal at 514 nm rises by approximately 10/sup 3/ in approximately 60 nsec and provides a measure of regrowth velocity. Beyond 200 nsec the much slower transmission rise is used to provide an estimate of the Si cooling rate. The difference in transmission observed between initially crystalline and initially amorphous Si provide an estimate of the latent heat of recrystallization of the amorphous phase.

  14. Theoretical limit of repeater spacing in an optical transmission line utilizing Raman amplification

    Science.gov (United States)

    Nakashima, T.; Seikai, S.; Nakazawa, M.; Negishi, Y.

    1986-08-01

    The limit of repeater spacing is investigated theoretically for optical transmission lines utilizing stimulated Raman scattering to amplify the signal light. Achievable repeater spacing is numerically estimated on the basis of coupled power equations and measured fiber characteristics for various signal wavelengths and relative index differences. Three types of transmission line configurations are considered, i.e., utilization of forward only, backward only, and bidirectional amplification. In the third case, a transmission distance of more than 400 km is predicted for an input signal light power of 100 microW, a signal wavelength of 1.57 microns, and a pump power of 0.5 W using a fiber with a relative index difference of 1 percent for signal light amplification.

  15. Opto-mechanical design for transmission optics in cryogenic IR instrumentation

    Science.gov (United States)

    Kroes, Gabby; Kragt, Jan, II; Navarro, Ramon; Elswijk, Eddy; Hanenburg, Hiddo

    2008-07-01

    ASTRON is involved in the development and realization of various optical astronomical instruments for ground-based as well as space telescopes, with a focus on near- and mid-infrared instrumentation. ASTRON has developed, among others, cryogenic optics for the first generation ESO VLT and VLTI instruments VISIR, MIDI and the SPIFFI 2K-camera for SINFONI. Currently under construction are MIRI for the James Webb Space Telescope and X-shooter for the second generation ESO VLT instrumentation, while the initial design of several ELT instruments has started. Mounting optics is always a compromise between firmly fixing the optics and preventing stresses within the optics. The fixing should ensure mechanical stability and thus accurate positioning in various gravity orientations, temperature ranges, during launch, transport or earthquake. On the other hand, the fixings can induce deformations and sometimes birefringence in the optics and thus cause optical errors. Even cracking or breaking of the optics is a risk, especially at the cryogenic temperatures required in instruments for infrared astronomy, where differential expansion of various materials amounts easily to several millimetres per meter. Special kinematic mounts are therefore needed to ensure both accurate positioning and low stress. Though ASTRON is involved in the full realization of instruments from initial design to commissioning, this paper concentrates on the opto-mechanical design of optics mountings, especially for large transmission optics in cryogenic circumstances. It describes the development of temperature-invariant ("a-thermal"), kinematic designs and how they are implemented in instruments such as SPIFFI and X-shooter.

  16. Effects of atmosphere on free-space optical transmission at 1.55 μm

    Science.gov (United States)

    Zeller, John; Manzur, Tariq

    2010-10-01

    Free-space optics (FSO) holds the potential for high bandwidth communication, but atmospheric conditions can significantly affect the capability of this type of communication system to transfer information consistently and operate effectively. The effects of atmosphere on FSO communication and consequent optimal wavelength range for transmission are investigated through MODTRAN-based modeling of 1.55 μm transmission for multiple elevation angles in atmospheric weather conditions including clear maritime, desert extinction, and various levels of rain and fog, to simulate surface-to-surface and surface-to-air FSO communication networks. Furthermore, atmospheric, free-space, and scintillation losses are analyzed for optical path lengths of 2 km to determine minimum transmit power required for successful data reception. In addition, FSO transmitter and receiver circuits were designed to optically relay analog video signals and their operation verified at path distances of up to 130 m. Using advanced laser sources to provide illumination at infrared wavelengths, particularly around the eye-safe 1.55 μm wavelength, it should be possible to overcome many transmission limitations associated with atmospheric conditions such as adverse weather and turbulence.

  17. 640 Gbaud (1.28 Tbit/s/ch) optical Nyquist pulse transmission over 525 km with substantial PMD tolerance.

    Science.gov (United States)

    Harako, Koudai; Seya, Daiki; Hirooka, Toshihiko; Nakazawa, Masataka

    2013-09-01

    We report a substantial increase in PMD tolerance in a single-channel ultrahigh-speed transmission using optical Nyquist pulses. We demonstrate both analytically and experimentally a large reduction in depolarization-induced crosstalk with optical Nyquist pulses, which is one of the major obstacles facing polarization-multiplexed ultrashort pulse transmission. By taking advantage of the high PMD tolerance, a low-penalty 1.28 Tbit/s/ch optical Nyquist TDM transmission at 640 Gbaud was achieved over 525 km.

  18. Development of Laser Beam Transmission Strategies for Future Ground-to-Space Optical Communications

    Science.gov (United States)

    Wilson, Keith E.; Kovalik, Joseph M.; Biswas, Abhijit; Roberts, William T.

    2007-01-01

    Optical communications is a key technology to meet the bandwidth expansion required in the global information grid. High bandwidth bi-directional links between sub-orbital platforms and ground and space terminals can provide a seamless interconnectivity for rapid return of critical data to analysts. The JPL Optical Communications Telescope Laboratory (OCTL) is located in Wrightwood California at an altitude of 2.2.km. This 200 sq-m facility houses a state-of- the-art 1-m telescope and is used to develop operational strategies for ground-to-space laser beam propagation that include safe beam transmission through navigable air space, adaptive optics correction and multi-beam scintillation mitigation, and line of sight optical attenuation monitoring. JPL has received authorization from international satellite owners to transmit laser beams to more than twenty retro-reflecting satellites. This paper presents recent progress in the development of these operational strategies tested by narrow laser beam transmissions from the OCTL to retro-reflecting satellites. We present experimental results and compare our measurements with predicted performance for a variety of atmospheric conditions.

  19. Novel approach for simultaneous wireless transmission and evaluation of optical sensors

    Science.gov (United States)

    Neumann, Niels; Schuster, Tobias; Plettemeier, Dirk

    2014-11-01

    Optical sensors can be used to measure various quantities such as pressure, strain, temperature, refractive index, pH value and biochemical reactions. The interrogation of the sensor can be performed spectrally or using a simple power measurement. However, the evaluation of the sensor signal and the subsequent radio transmission of the results is complicated and costly. A sophisticated system setup comprising a huge number of electrooptical components as well as a complete radio module is required. This is not only expensive and unreliable but also impractical within harsh environment, in limited space and in inaccessible areas. Radio-over-Fiber (RoF) technology implies signals modulated on an electrical carrier being transmitted over fiber by using optical carriers. Combining RoF techniques and optical sensors, a new class of measurement devices readable by a radio interfaces is introduced in this paper. These sensors use a modulated input signal generated by a RoF transmitter that { after being influenced by the optical sensor-is directly converted into a radio signal and transmitted. This approach enables remote read-outs of the sensor by means of wireless evaluation. Thus, costly, voluminous, power hungry and sensitive equipment in the vicinity of the measurement location is avoided. The equipment can be concentrated in a central location supporting existing radio transmission schemes (e.g. WiFi).

  20. All-optical delay technique for supporting multiple antennas in a hybrid optical - wireless transmission system

    DEFF Research Database (Denmark)

    Prince, Kamau; Chiuchiarelli, A; Presi, M

    2008-01-01

    We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency.......We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency....

  1. Seamless Transmission between Single-Mode Optical Fibers Using Free Space Optics System

    Science.gov (United States)

    Yoshida, Koichi; Tsujimura, Takeshi

    This paper presents a free space optics system installed between two single-mode optical fibers (SMFs). The result looks as if the two SMFs were seamlessly connected without the need for any photoelectric devices. Misalignments between the two SMFs caused by disturbances are actively compensated for by introducing a laser beam controller that incorporates an opto-mechatronic mechanism with four degrees of freedom. Experiments using a prototype are conducted to verify the effectiveness of the proposed FSO system for initial beam acquisition and beam tracking when there is a vibration disturbance.

  2. Effects of interplay between metal subwavelength slits on extraordinary optical transmission

    Institute of Scientific and Technical Information of China (English)

    Wei Fei-Fei; Wang Huai-Yu; Zhou Yun-Song

    2013-01-01

    In this paper we study the extraordinary optical transmission of one-dimensional multi-slits in an ideal metal film.The transmissivity is calculated as a function of various structural parameters.The transmissivity oscillates,with the period being just the light wavelength,as a function of the spacing between slits.As the number of slits increases,the transmissivity varies in one of three ways.It can increase,attenuate,or remain basically unchanged,depending on the spacing between slits.Each way is in an oscillatory manner.The slit interaction responsible for the oscillating transmission strength that depends on slit spacing is the subject of more detailed investigation.The interaction most intuitively manifests as a current distribution in the metal surface between slits.We find that this current is attenuated in an oscillating fashion from the slit comers to the center of the region between two adjacent slits,and we present a mathematical expression for its waveform.

  3. Transmission stability and Raman-induced amplitude dynamics in multichannel soliton-based optical waveguide systems

    Science.gov (United States)

    Peleg, Avner; Nguyen, Quan M.; Tran, Thinh P.

    2016-12-01

    We study transmission stability and dynamics of pulse amplitudes in N-channel soliton-based optical waveguide systems, taking into account second-order dispersion, Kerr nonlinearity, delayed Raman response, and frequency dependent linear gain-loss. We carry out numerical simulations with systems of N coupled nonlinear Schrödinger (NLS) equations and compare the results with the predictions of a simplified predator-prey model for Raman-induced amplitude dynamics. Coupled-NLS simulations for single-fiber transmission with 2 ≤ N ≤ 4 frequency channels show stable oscillatory dynamics of soliton amplitudes at short-to-intermediate distances, in excellent agreement with the predator-prey model's predictions. However, at larger distances, we observe transmission destabilization due to resonant formation of radiative sidebands, which is caused by Kerr nonlinearity. The presence of linear gain-loss in a single fiber leads to a limited increase in transmission stability. Significantly stronger enhancement of transmission stability is achieved in a nonlinear N-waveguide coupler due to efficient suppression of radiative sideband generation by the linear gain-loss. As a result, the distances along which stable Raman-induced dynamics of soliton amplitudes is observed are significantly larger in the waveguide coupler system compared with the single-fiber system.

  4. Theoretical and experimental investigation of direct detection optical OFDM transmission using beat interference cancellation receiver.

    Science.gov (United States)

    Nezamalhosseini, S Alireza; Chen, Lawrence R; Zhuge, Qunbi; Malekiha, Mahdi; Marvasti, Farokh; Plant, David V

    2013-07-01

    We theoretically and experimentally evaluate a beat interference cancellation receiver (BICR) for direct detection optical orthogonal frequency-division multiplexing (DD-OFDM) systems that improves the spectral efficiency (SE) by reducing the guard band between the optical carrier and the optical OFDM signal while mitigating the impact of signal-signal mixing interference (SSMI). Experimental results show that the bit-error-rate (BER) is improved by about three orders of magnitude compared to the conventional receiver after 320 km single-mode fiber (SMF) transmission for 10 Gb/s data with a 4-QAM modulation using reduced guard band single-sideband OFDM (RSSB-OFDM) signal with 1.67 bits/s/Hz SE.

  5. A Theoretical and Experimental Research on Terahertz Electro-Optic Sampling at Near-Zero Optical Transmission Point

    Institute of Scientific and Technical Information of China (English)

    XU Shi-Xiang; CAI Hua

    2008-01-01

    We report an improved theoretical model to characterize terahertz electro-optic(EO)sampling detection operating at near crossed-polarizer design by considering the nonzero minimal transmission of polarizers and the polarization purlty of laser beam.The proof-of-concept experiments show that the model can give quiet reasonable explanations on many experimental phenomena in THz EO detection,e.g.the modulation depth vs the different optical biases,the noise level from the balance detector vs the input probe beam power,the main origin of the background light and the incomplete cancellation of noise from the laser intensity fluctuation in balanced detection.The terahertz signals and the noises are also measured based on two different EO sampling schemes for comparison.The measured results support our model very well.

  6. Rate-adaptive modulation and coding for optical fiber transmission systems

    Science.gov (United States)

    Gho, Gwang-Hyun; Kahn, Joseph M.

    2011-01-01

    Rate-adaptive optical transmission techniques adjust information bit rate based on transmission distance and other factors affecting signal quality. These techniques enable increased bit rates over shorter links, while enabling transmission over longer links when regeneration is not available. They are likely to become more important with increasing network traffic and a continuing evolution toward optically switched mesh networks, which make signal quality more variable. We propose a rate-adaptive scheme using variable-rate forward error correction (FEC) codes and variable constellations with a fixed symbol rate, quantifying how achievable bit rates vary with distance. The scheme uses serially concatenated Reed-Solomon codes and an inner repetition code to vary the code rate, combined with singlecarrier polarization-multiplexed M-ary quadrature amplitude modulation (PM-M-QAM) with variable M and digital coherent detection. A rate adaptation algorithm uses the signal-to-noise ratio (SNR) or the FEC decoder input bit-error ratio (BER) estimated by a receiver to determine the FEC code rate and constellation size that maximizes the information bit rate while satisfying a target FEC decoder output BER and an SNR margin, yielding a peak rate of 200 Gbit/s in a nominal 50-GHz channel bandwidth. We simulate single-channel transmission through a long-haul fiber system incorporating numerous optical switches, evaluating the impact of fiber nonlinearity and bandwidth narrowing. With zero SNR margin, we achieve bit rates of 200/100/50 Gbit/s over distances of 650/2000/3000 km. Compared to an ideal coding scheme, the proposed scheme exhibits a performance gap ranging from about 6.4 dB at 650 km to 7.5 dB at 5000 km.

  7. Transmission Maps of the ACIS UV/Optical Blocking Filter Flight Units

    Science.gov (United States)

    Townsley, L. K.; Broos, P. S.; Mackay, J. F.

    1996-05-01

    The AXAF CCD Imaging Spectrometer (ACIS) employs filters made of Lexan coated on both sides with aluminum to block optical and UV light, so that the CCDs see only X-radiation from astronomical targets. These filters must be characterized by spatially mapping their transmission at various astrophysically and instrumentally important energies. The Penn State University ACIS team determined that a synchrotron, where a variety of well-determined X-ray energies is available, would provide the best calibration. We measured engineering grade UV/optical blocking filters at the University of Wisconsin Synchrotron Radiation Center (SRC) in June and October 1995, modified the hardware and software on a dry run in January 1996, and just completed the calibration of the flight filters in March 1996. The Multilayer Beamline at the SRC was used for these measurements because it can access several energies important to the calibration and its built-in, computer-controlled x-z stage allows us to map the filters automatically with user-specified spatial resolution. These transmission maps formed the basis for choosing the actual flight filter units from the set of filters manufactured with flight specifications. We obtained transmission measurements at five energies in the range 200-2000 eV. We present here best-fit models of the filter transmission based on these data points. Better than one percent accuracy in transmission as a function of energy was achieved over the entire filter area on scales corresponding to thirty arcseconds in the focal plane of AXAF (the amplitude of the planned aspect dither of the spacecraft). The pair of filters (one for the Imaging array and one for the Spectroscopy array) selected for flight will be installed on the ACIS focal plane in early summer.

  8. Factorial Based Response Surface Modeling with Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon

    Science.gov (United States)

    We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...

  9. Experimental Investigation of Transmission Properties and All-Optical Label Swapping of Orthogonal IM/FSK Labeled Signals

    Institute of Scientific and Technical Information of China (English)

    Pablo; V.; Holm-Nielsen; Christophe; Peucheret; Idelfonso; Tafur; Monroy; Palle; Jeppesen

    2003-01-01

    OpticallylabeledIM/FSKsignalsaretransmittedover50kmofSMFunderdifferentcompensationschemes.All-optical label swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall power penalty.

  10. Optical wireless transmission of 405 nm, 1.45 Gbit/s optical IM/DD-OFDM signals through a 4.8 m underwater channel.

    Science.gov (United States)

    Nakamura, Kazuhiko; Mizukoshi, Izumi; Hanawa, Masanori

    2015-01-26

    In this paper, we experimentally demonstrate wireless transmission of optical intensity modulation/direct detection-orthogonal frequency division multiplexing (IM/DD-OFDM) signals in an underwater channel using a field programmable gate array based real-time transmitter. The real-time transmission of a 405 nm 1.45 Gbit/s optical OFDM signal through a 4.8 m underwater channel with an error vector magnitude of approximately 10% was successfully achieved.

  11. A precise optical transmission spectrum of the inflated exoplanet WASP-52b

    Science.gov (United States)

    Louden, Tom; Wheatley, Peter J.; Irwin, Patrick G. J.; Kirk, James; Skillen, Ian

    2017-09-01

    We have measured a precise optical transmission spectrum for WASP-52b, a highly inflated hot Jupiter with an equilibrium temperature of 1300 K. Two transits of the planet were observed spectroscopically at low resolution with the auxiliary-port camera on the William Herschel Telescope, covering a wide range of 4000-8750 Å. We use a Gaussian process approach to model the correlated noise in the multiwavelength light curves, resulting in a high precision relative transmission spectrum with errors of the order of a pressure scaleheight. We attempted to fit a variety of different representative model atmospheres to the transmission spectrum, but did not find a satisfactory match to the entire spectral range. For the majority of the covered wavelength range (4000-7750 Å), the spectrum is flat, and can be explained by an optically thick and grey cloud layer at 0.1 mbar, but this is inconsistent with a slightly deeper transit at wavelengths >7750 Å. We were not able to find an obvious systematic source for this feature, so this opacity may be the result of an additional unknown absorber.

  12. Layered ACO-OFDM for intensity-modulated direct-detection optical wireless transmission.

    Science.gov (United States)

    Wang, Qi; Qian, Chen; Guo, Xuhan; Wang, Zhaocheng; Cunningham, David G; White, Ian H

    2015-05-04

    Layered asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) with high spectral efficiency is proposed in this paper for optical wireless transmission employing intensity modulation with direct detection. In contrast to the conventional ACO-OFDM, which only utilizes odd subcarriers for modulation, leading to an obvious spectral efficiency loss, in layered ACO-OFDM, the subcarriers are divided into different layers and modulated by different kinds of ACO-OFDM, which are combined for simultaneous transmission. In this way, more subcarriers are used for data transmission and the spectral efficiency is improved. An iterative receiver is also proposed for layered ACO-OFDM, where the negative clipping distortion of each layer is subtracted once it is detected so that the signals from different layers can be recovered. Theoretical analysis shows that the proposed scheme can improve the spectral efficiency by up to 2 times compared with conventional ACO-OFDM approaches with the same modulation order. Meanwhile, simulation results confirm a considerable signal-to-noise ratio gain over ACO-OFDM at the same spectral efficiency.

  13. Effect of Initial Chirping and Pulse Shape on 10 Gb/s Optical Pulse Transmission in Birefringent Nonlinear Fibers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Numerical method to solve the problem related with theinteractive effect of dispersion (both chromatic dispersion and polarization mode dispersion) and nonlinearity on optical pulse transmission is present. Evolutions of pulses with various initial chirping and shape at bit-rate of 10 Gb/s are simulated and compared. Gaussian pulse with appropriate prechirping is propitious for high bit-rate transmission.

  14. Multispectral optical enhanced transmission of a continuous metal film coated with a plasmonic core-shell nanoparticle array

    Science.gov (United States)

    Liu, Gui-qiang; Hu, Ying; Liu, Zheng-qi; Cai, Zheng-jie; Zhang, Xiang-nan; Chen, Yuan-hao; Huang, Kuan

    2014-04-01

    We propose and show multispectral optical enhanced transmission in the visible and near-infrared region in a continuous metal film coated with a two-dimensional (2D) hexagonal non-close-packed plasmonic array. The plasmonic array consists of metal/dielectric multilayer core-shell nanoparticles. The excitation of near-field plasmon resonance coupling between adjacent core-shell nanoparticles, plasmon resonance coupling between adjacent metal layers in the nanoparticle, and surface plasmon (SP) waves on the metal film are mainly responsible for the multispectral optical enhanced transmission behavior. The multispectral optical enhanced transmission response could be highly modified in the wavelength range, transparent bandwidth and transmission intensity by varying the geometry parameters including the gap distance between adjacent plasmonic nanoparticles, the size of metal core and the thickness of dielectric layer between the metal layers. In addition, the number of optical enhanced transmission bands increases with the number of metal layers in the plasmonic nanoparticle. The proposed structure shows many merits such as the deep sub-wavelength size, multispectral optical enhanced transmission bands as well as fully retained electric and mechanical properties of the natural metal. These merits may provide promising applications for highly integrated optoelectronic devices including plasmonic filters, nanoscale multiplexers, and nonlinear optics.

  15. Potential of optical spectral transmission measurements for joint inflammation measurements in rheumatoid arthritis patients

    Science.gov (United States)

    Meier, A. J. Louise; Rensen, Wouter H. J.; de Bokx, Pieter K.; de Nijs, Ron N. J.

    2012-08-01

    Frequent monitoring of rheumatoid arthritis (RA) patients enables timely treatment adjustments and improved outcomes. Currently this is not feasible due to a shortage of rheumatologists. An optical spectral transmission device is presented for objective assessment of joint inflammation in RA patients, while improving diagnostic accuracy and clinical workflow. A cross-sectional, nonrandomized observational study was performed with this device. In the study, 77 proximal interphalangeal (PIP) joints in 67 patients have been analyzed. Inflammation of these PIP joints was also assessed by a rheumatologist with a score varying from 1 (not inflamed) to 5 (severely inflamed). Out of 77 measurements, 27 were performed in moderate to strongly inflamed PIP joints. Comparison between the clinical assessment and an optical measurement showed a correlation coefficient r=0.63, p<0.001, 95% CI [0.47, 0.75], and a ROC curve (AUC=0.88) that shows a relative good specificity and sensitivity. Optical spectral transmission measurements in a single joint correlate with clinical assessment of joint inflammation, and therefore might be useful in monitoring joint inflammation in RA patients.

  16. Using a validated transmission model for the optimization of bundled fiber optic displacement sensors.

    Science.gov (United States)

    Moro, Erik A; Todd, Michael D; Puckett, Anthony D

    2011-12-10

    A variety of intensity-modulated optical displacement sensor architectures have been proposed for use in noncontacting sensing applications, with one of the most widely implemented architectures being the bundled displacement sensor. To the best of the authors' knowledge, the arrangement of measurement fibers in previously reported bundled displacement sensors has not been configured with the use of a validated optical transmission model. Such a model has utility in accurately describing the sensor's performance a priori and thereby guides the arrangement of the fibers within the bundle to meet application-specific performance needs. In this paper, a recently validated transmission model is used for these purposes, and an optimization approach that employs a genetic algorithm efficiently explores the design space of the proposed bundle sensor architecture. From the converged output of the optimization routine, a bundled displacement sensor configuration is designed and experimentally tested, offering linear performance with a sensitivity of -0.066 μm(-1) and displacement measurement error of 223 μm over the axial displacement range of 6-8 mm. It is shown that this optimization approach may be generalized to determine optimized bundle configurations that offer high-sensitivity performance, with an acceptable error level, over a variety of axial displacement ranges. This document has been approved by Los Alamos National Laboratory for unlimited public release (LA-UR 11-03413). © 2011 Optical Society of America

  17. Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

    CERN Document Server

    Ziolkowski, M; Buchholz, P; Ciliox, A; Gan, K K; Holder, M; Johnson, M; Kagan, H; Kass, R; Nderitu, S; Rahimi, A; Rush, C J; Smith, S; Ter-Antonian, R; Zoeller, M M

    2004-01-01

    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the CERN Large Hadron Collider (LHC). The first circuit is a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode to be used for 80 Mbit/s data transmission from the detector. The second circuit is a Bi-Phase Mark, decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode on the detector side. During ten years of operation at the LHC, the ATLAS optical link circuitry will be exposed to a maximum total fluence of 10/sup 15/ 1-MeV-equivalent neutrons per cm/sup 2/. We have successfully implemented both ASICs in a commercial 0.25 mu m CMOS technology using standard layout techniques to enhance the radiation tolerance. Both chips are four- channel devices compatible with common cathode PIN and VCSEL arrays. We present results from final prototype circuits and from irradiation studies of both circuits with 24 GeV protons up to a total dose of 57 Mrad. (3 refs).

  18. A ground-based optical transmission spectrum of WASP-6b

    Energy Technology Data Exchange (ETDEWEB)

    Jordán, Andrés; Espinoza, Néstor; Rabus, Markus [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); Eyheramendy, Susana [Departmento de Estadística, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); Sing, David K. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Désert, Jean-Michel [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Bakos, Gáspár Á. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); López-Morales, Mercedes; Szentgyorgyi, Andrew [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Maxted, Pierre F. L. [Astrophysics Group, Keele University, Staffordshire ST5 5BG (United Kingdom); Triaud, Amaury H. M. J. [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-12-01

    We present a ground-based optical transmission spectrum of the inflated sub-Jupiter-mass planet WASP-6b. The spectrum was measured in 20 spectral channels from 480 nm to 860 nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the Inamori-Magellan Areal Camera and Spectrograph on the Baade Telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensates in the atmosphere of WASP-6b. WASP-6b therefore appears to be yet another massive exoplanet with evidence for a mostly featureless transmission spectrum, underscoring the importance that hazes and condensates can have in determining the transmission spectra of exoplanets.

  19. Transmission Performance Analysis of Fiber Optical Parametric Amplifiers for WDM System

    Directory of Open Access Journals (Sweden)

    Xiaohong Jiang

    2009-01-01

    Full Text Available A numerical analysis is presented on the long-haul wavelength-division multiplexing (WDM transmission system employing fiber-optic parametric amplifier (FOPA cascades based on one-pump FOPA model with Raman Effect taken into account. The end-to-end equalization scheme is applied to optimize the system features in terms of proper output powers and signal-to-noise ratios (SNRs in all the channels. The numerical results show that—through adjusting the fiber spans along with the number of FOPAs as well as the channel powers at the terminals in a prescribed way—the transmission distance and system performance can be optimized. By comparing the results generated by different lengths of fiber span, we come to the optimal span length to achieve the best transmission performance. Furthermore, we make a comparison among the long-haul WDM transmission systems employing different inline amplifiers, namely, FOPA, erbium-doped fiber amplifier (EDFA, and Fiber Raman Amplifier (FRA. FOPA demonstrates its advantage over the other two in terms of system features.

  20. Optical control of resonant light transmission for an atom-cavity system

    CERN Document Server

    Sharma, Arijit; Sawant, Rahul V; Sheikholeslami, G; Budker, D; Rangwala, S A

    2015-01-01

    We demonstrate the manipulation of transmitted light through an optical Fabry-Perot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the $^{87}$Rb D$_{2}$ ($F=2/F=1$) $\\leftrightarrow F'$ manifold, is controlled by transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of cavity mode control is the precipitious destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity, on intersection of the transverse control beam with the cavity mode. Both the steady state and transient response are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief.

  1. Using a Semiconductor-to-Metal Transition to Control Optical Transmission through Subwavelength Hole Arrays

    Directory of Open Access Journals (Sweden)

    E. U. Donev

    2008-01-01

    Full Text Available We describe a simple configuration in which the extraordinary optical transmission effect through subwavelength hole arrays in noble-metal films can be switched by the semiconductor-to-metal transition in an underlying thin film of vanadium dioxide. In these experiments, the transition is brought about by thermal heating of the bilayer film. The surprising reverse hysteretic behavior of the transmission through the subwavelength holes in the vanadium oxide suggest that this modulation is accomplished by a dielectric-matching condition rather than plasmon coupling through the bilayer film. The results of this switching, including the wavelength dependence, are qualitatively reproduced by a transfer matrix model. The prospects for effecting a similar modulation on a much faster time scale by using ultrafast laser pulses to trigger the semiconductor-to-metal transition are also discussed.

  2. Surface-mode model of the extraordinary optical transmission without plasmons.

    Science.gov (United States)

    Xie, Yunya; Liu, Haitao; Jia, Hongwei; Zhong, Ying

    2015-03-09

    We propose a microscopic surface-mode model for the extraordinary optical transmission (EOT) through subwavelength metallic slit array covered with a thin dielectric layer under illumination of transverse-electric (TE) polarization. Remarkably, surface plasmon polarizations (SPPs) do not exist for this polarization. It is commonly believed that the waveguide mode in the dielectric layer plays a role similar to that of the SPP in classical EOT. To check the intuitive belief, we derive a surface-mode model by considering the multiple scattering process of the fundamental waveguide mode and neglecting all other residual field in the thin dielectric layer. The model captures the main feature of EOT and provides a phase-matching condition to predict the transmission resonance. Quantitative comparison between fully-vectorial calculations and model predictions shows that besides the fundamental waveguide mode, other residual field in the thin dielectric layer also contributes to the EOT without SPP.

  3. 160-Gb/s polarization-multiplexing optical NRZ-DQPSK transmission using differential detection

    Institute of Scientific and Technical Information of China (English)

    He Wen; Jinxin Liao; Xiaoping Zheng; Hanyi Zhang

    2011-01-01

    Using differential detection,we perform polarization-multiplexing 160-Gb/s optical non-return-to-zero (NRZ) differential quadrature phase shift keying (DQPSK) signal transmission over 100-km standard single mode fiber at a bit error rate (BER) of less than 10-9.The enabling technology includes clock recovery,fine dispersion compensation,and polarization tracking for de-multiplexing.Furthermore,a hybrid clock recovery scheme is proposed.The scheme is realized with ordinary devices using an optoelectrical modulator to down-convert the clock frequency and a phase-locked loop for filtering,which can provide an indication signal that simultaneouslv monitors residual disoersion and tracking polarization.Given the ever increasing bandwidth demands (e.g.,for imaging,demand of video,gaming,etc.),the capacity of optical transmission systems is being constantly raised through the application of several approaches that include the use of advanced modulation formats with higher spectral efficiency,increasing the symbol rate of each channel,and orthogonal polarization multiplexing with idcntical wavelengths;these approaches are enabled by coherent detection[1-3].%Using differential detection, we perform polarization-multiplexing 160-Gb/s optical non-return-to-zero (NRZ) differential quadrature phase shift keying (DQPSK) signal transmission over 100-km standard single mode fiber at a bit error rate (BER) of less than 10~9. The enabling technology includes clock recovery, fine dispersion compensation, and polarization tracking for de-multiplexing. Furthermore, a hybrid clock recovery scheme is proposed. The scheme is realized with ordinary devices using an optoclectrical modulator to down-convert the clock frequency and a phase-locked loop for filtering, which can provide an indication signal that simultaneously monitors residual dispersion and tracking polarization.

  4. Demonstration of flat-band image transmission in optically induced Lieb photonic lattices.

    Science.gov (United States)

    Xia, Shiqiang; Hu, Yi; Song, Daohong; Zong, Yuanyuan; Tang, Liqin; Chen, Zhigang

    2016-04-01

    We present a simple, yet effective, approach for optical induction of Lieb photonic lattices, which typically rely on the femtosecond laser writing technique. Such lattices are established by judiciously overlapping two sublattices (an "egg-crate" lattice and a square lattice) with different periodicities through a self-defocusing photorefractive medium. Furthermore, taking advantage of the superposition of localized flat-band states inherent in the Lieb lattices, we demonstrate distortion-free image transmission in such two-dimensional perovskite-like photonic structures. Our experimental observations find good agreement with numerical simulations.

  5. DSP-based optical modulation technique for long-haul transmission

    Science.gov (United States)

    Yoshida, T.; Sugihara, T.; Uto, K.

    2015-01-01

    Fiber nonlinearity and equalization-enhanced phase noise (EEPN) generate rapid perturbations and critically limit the system capacity and range of long-haul optical transmission. It is possible to cancel the rapid perturbations by introducing a particular correlation between multiple signals at the transmitter and analyzing the received signals using digital signal processing. In this paper, we review our proposed techniques to cancel rapid perturbations of polarization multiplexed signals due to fiber nonlinearity and EEPN. Numerical simulation of quaternary phase-shift keying based signals shows 1.2 dB and 0.5 dB improvement respectively from the proposed cancellation techniques for fiber nonlinearity and EEPN.

  6. LogAmp electronics and optical transmission for the new SPS beam position measurement system

    Science.gov (United States)

    Bogey, T.; Deplano, C.; Gonzalez, J. L.; Savioz, J. J.

    2013-12-01

    A new front-end board is under development for the CERN SPS Multi ORbit Position System (MOPOS). Based on logarithmic amplifiers, it measures the beam position over a large dynamic range of beam intensities and resolves the multi-batch structure of the SPS beams. Analogue data are digitized at 10 MS/s, packed in frames by an FPGA and on every turn sent to the readout board, via a 2.4 Gb/s optical transmission link. A first prototype has been successfully tested with several SPS beams. This paper presents an overall description of the system and its capabilities highlighted by the first beam measurements.

  7. LogAmp electronics and Optical Transmission for the new SPS Beam Position Measurement System

    CERN Document Server

    Deplano, C; Gonzalez, J L; Savioz, J J

    2013-01-01

    A new front-end board is under development for the CERN SPS Multi ORbit Position System (MOPOS). Based on logarithmic amplifiers, it measures the beam position over a large dynamic range of beam intensities and resolves the multi-batch structure of the SPS beams. Analogue data are digitized at 10 MS/s, packed in frames by an FPGA and on every turn sent to the readout board, via a 2.4 Gb/s optical transmission link. A first prototype has been successfully tested with several SPS beams. This paper presents an overall description of the system and its capabilities highlighted by the first beam measurements.

  8. Digital pilot aided carrier frequency offset estimation for coherent optical transmission systems.

    Science.gov (United States)

    Zhao, Donghe; Xi, Lixia; Tang, Xianfeng; Zhang, Wenbo; Qiao, Yaojun; Zhang, Xiaoguang

    2015-09-21

    We present a digital pilot aided carrier frequency offset estimation (FOE) method for coherent optical transmission systems. Unlike the conventional pilot tone insertion scheme, the pilot of the proposed method is generated in a digital manner and can serve as a good FOE indicator. Aided by this kind of digital pilot, the FOE is implemented by determining the location of the digital pilot in the spectrum. Theoretical analysis and numerical simulations show that the proposed method has the advantages in wide range, high accuracy, modulation formats independent, no need to remove the modulation, and high tolerance to the residual chromatic dispersion (CD) and polarization mode dispersion (PMD).

  9. Optical transmission and laser ablation of pathologically changed eye lens capsule

    Energy Technology Data Exchange (ETDEWEB)

    Gamidov, A A; Bolshunov, A V [Research Institute of Eye Diseases, Russian Academy of Medical Sciences, Moscow (Russian Federation); Yuzhakov, A V; Shcherbakov, E M; Baum, O I; Sobol, E N [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

    2015-02-28

    Optical transmission and ablation mechanisms in the secondary cataract films under the impact of 1.06-mm laser radiation are studied. The comparison of incident and transmitted (paraxial) radiation power at different values of the power density is carried out for two types of the eye lens capsule tissue (hard and soft) possessing different optical and mechanical properties. It is found that the effective attenuation coefficient for soft films is almost five times as large as that for the hard ones. The obtained measurement data on the transparency variation in the process of laser action allow the temperature evaluation and the determination of dominant mechanism of laser ablation, as well as the development of recommendations, providing the prevention or reduction of possible side effects. The obtained results can be used to optimise the regimes of laser impact in the process of the opacified lens capsule removal.

  10. Enhanced Transmission Stability of Polarization Solitons in Birefringent Fibres with an Optical Phase Conjugator

    Institute of Scientific and Technical Information of China (English)

    陈伟成; 谢嘉宁; 路洪; 徐文成

    2003-01-01

    An optical phase conjugator is used to enhance transmission stability of polarization solitons in highly birefringent fibres. Two polarization solitons form a breather in fibres with low birefringence firstly and the optical phase conjugator is used to make the spectra of polarization solitons converse, which results in the fact that the polarization soliton along the fast axis is compressed due to the strengthened self-phase modulation effect. Two polarization solitons are compressed further due to the cross-phase modulation effect. The enhanced nonlinear effects make the central peak frequencies of two polarization solitons shift to the larger range in opposite directions so that they trap each other fully to suppress the effect of birefringence.

  11. Data transmission with twisted light through a free-space to fiber optical communication link

    Science.gov (United States)

    Brüning, Robert; Ndagano, Bienvenu; McLaren, Melanie; Schröter, Siegmund; Kobelke, Jens; Duparré, Michael; Forbes, Andrew

    2016-03-01

    Mode division multiplexing (MDM), where information is transmitted in the spatial modes of light, is mooted as a future technology with which to transmit large bits of information. However, one of the key issues in optical communication lies in connecting free-space to optical fiber networks, otherwise known as the ‘last mile’ problem. This is particularly problematic for MDM as the eigenmodes of free-space and fibers are in general not the same. Here we demonstrate a data transmission scheme across a free-space and fiber link using twisted light in the form of Laguerre-Gaussian (LG) azimuthal modes. As a proof-of-principle we design and implement a custom fiber where the supported LG modes can be grouped into five non-degenerate sets, and successfully transmit a gray-scale image across the composite link using one mode from each group, thereby ensuring minimal crosstalk.

  12. Experimental study of non-binary LDPC coding for long-haul coherent optical QPSK transmissions.

    Science.gov (United States)

    Zhang, Shaoliang; Arabaci, Murat; Yaman, Fatih; Djordjevic, Ivan B; Xu, Lei; Wang, Ting; Inada, Yoshihisa; Ogata, Takaaki; Aoki, Yasuhiro

    2011-09-26

    The performance of rate-0.8 4-ary LDPC code has been studied in a 50 GHz-spaced 40 Gb/s DWDM system with PDM-QPSK modulation. The net effective coding gain of 10 dB is obtained at BER of 10(-6). With the aid of time-interleaving polarization multiplexing and MAP detection, 10,560 km transmission over legacy dispersion managed fiber is achieved without any countable errors. The proposed nonbinary quasi-cyclic LDPC code achieves an uncoded BER threshold at 4×10(-2). Potential issues like phase ambiguity and coding length are also discussed when implementing LDPC in current coherent optical systems. © 2011 Optical Society of America

  13. Performances of Neural Networks and LDPC Decoders for OFDM High Speed Transmission in Optical Fiber

    Directory of Open Access Journals (Sweden)

    Sanou Serge Roland 1, 2 * , Zougmoré François 1 , Kébré Marcel 1 , Koalaga Zacharie 1 , Doumounia Ali

    2013-09-01

    Full Text Available This paper presents a comparison of the performances of coded OFDM (Orthogonal Frequency Division Multiplexing for optical broadband transmission using Random Neural Network (RNN, a variant of RNN, Soft Decision Decoding (SDD and LDPC channel decoding techniques. The performance evaluation is based firstly on the Error Vector Magnitude (EVM to assess the effects of imperfections in the optical channel, and secondly on the estimated Bit Error Rate (BER based on OSNR. The simulations are performed at a rate of 10Gb/s over 1000 km using VPI software cosimulation environment. The results show that the error correcting codes, particularly LDPC codes, are well suited and efficient for broadband.These codes provide satisfactory solutions for OFDM, reducing the effects of chromatic dispersion (CD, polarization mode dispersion (PMD, Intersymbol Interference(ISI and non-linearities.

  14. Optical nonlinearities and enhanced light transmission in soft-matter systems with tunable polarizabilities.

    Science.gov (United States)

    Man, Weining; Fardad, Shima; Zhang, Ze; Prakash, Jai; Lau, Michael; Zhang, Peng; Heinrich, Matthias; Christodoulides, Demetrios N; Chen, Zhigang

    2013-11-22

    We demonstrate a new class of synthetic colloidal suspensions capable of exhibiting negative polarizabilities, and observe for the first time robust propagation and enhanced transmission of self-trapped light over long distances that would have been otherwise impossible in conventional suspensions with positive polarizabilities. Such light penetration through the strong scattering environment is attributed to the interplay between optical forces and self-activated transparency effects while no thermal effect is involved. By judiciously mixing colloidal particles of both negative and positive polarizabilities, we show that the resulting nonlinear response of these systems can be fine-tuned. Our experimental observations are in agreement with theoretical analysis based on a thermodynamic model that takes into account particle-particle interactions. These results may open up new opportunities in developing soft-matter systems with engineered optical nonlinearities.

  15. Photonics integrations enabling high-end applications of InP in optical data transmissions

    Science.gov (United States)

    Zhang, Jiaming; Frateschi, Newton; Jambunathan, Ram; Choi, Wonjin; Bond, Aaron E.

    2005-10-01

    We present here results from a uniquely designed InP modulator chip combined with advanced packaging concepts, which enables high-end applications in optical data communications. An electroabsorption (EA) modulator, with a strained InGaAsP or InGaAlAs multiple quantum well structure, is monolithically integrated with a semiconductor optical amplifier. This design offers broad wavelength tunability while maintaining high extinction ratio, high optical output power, and high dispersion tolerance. The amplified EA modulator chip is co-packaged with a distributed feed back (DFB) laser ensuring separate optimization of the laser and modulator sections. The optical isolator, placed between the laser and modulator, completely eliminates adiabatic chirp. This Telcordia-qualified laser integrated modulator platform enables superior performance previously not thought possible for InP absorption based modulators. 11dB of dynamic extinction ratio, 5dBm of modulated output power, and +/-1200ps/nm or +1600ps/nm dispersion tolerance can be simultaneously achieved in un-amplified 10Gb/s data transmission. Full C-band tunability using a single device is also demonstrated with the LIM module. Extensive simulations and transmission system evaluations shows that with the controllable chirp, the cost-effective LIM performs as well as a Mach-Zehnder modulator in dispersion managed and amplified long-haul WDM systems. Lastly, the first uncooled 10Gb/s long-reach operation at 1550nm was demonstrated with LIM packages. Using a simple control algorithm, a constant modulated output power of 1dBm with less than 1dB dispersion penalty over 1600ps/nm single mode fiber is achieved in an 80 degrees environmental temperature range without any module temperature control. Utilizing the Al-based material system, also allows a reduced variation of the extinction ratio.

  16. All-Optical envelope detection and fiber transmission of wireless signals by external injection of a DFB laser

    DEFF Research Database (Denmark)

    Prince, Kamau; Tafur Monroy, Idelfonso

    2008-01-01

    We outline a novel method for all-optical envelope detection of wireless signals by exploiting cross-gain modulation effects in a distributed feedback laser operating with optical injection. We successfully demonstrate envelope detection of a 20-GHz carrier amplitude-shift-keying modulated signal...... at 2.5 Gb/s and its transmission over a 70-km optical fiber link. We present results including bit-error-rate measurements, signal waveforms, and receiver sensitivity penalties associated with envelope detection and fiber transmission....

  17. Effect of Overlaid Material on Optical Transmission of Side-Polished Fiber Made by Wheel Side Polishing

    Institute of Scientific and Technical Information of China (English)

    Zhe Chen; Chun-He Bai

    2008-01-01

    The performance of optical power transmission through a side-polished fiber on which materials of different refractive indices were overlaid is investigated. The experiments show that the transmitted optical power through the side-polished fiber varies with the refractive index of the overlaid material. The result of our experiments fits well the theoretical calculation.Side-polished fiber manufactured by wheel polishing method can be used not only to control optical power transmission through the fiber core but also as a refractive index sensor.

  18. All-fiber mode selective couplers for mode-division-multiplexed optical transmission

    Science.gov (United States)

    Chang, Sun Hyok; Kim, Kwangjoon; Lee, Joon Ki

    2017-01-01

    All-fiber mode selective coupler (MSC) is comprised of a few mode fiber (FMF) and a single mode fiber (SMF), coupling the LP01 mode of the SMF to a specific higher-order mode (HOM) of the FMF. In order to achieve high coupling ratio and low insertion loss, phase-matching condition between the LP01 mode of SMF arm and the HOM of FMF arm should be satisfied. A polished-type MSC is made by getting their cores into intimate contact. Prism coupling with a polished coupler block can measure the effective refractive index of the mode accurately. We propose and demonstrate three kinds of allfiber mode multiplexer that is composed of consecutive MSCs. 4-mode multiplexer can multiplex 4 modes of LP01, LP11, LP21, and LP02 by cascading LP11, LP21, and LP02 MSCs. It is used for MDM transmission of three modes with 120 Gb/s DP-QPSK signals. In order to enhance the signal transmission performance by receiving degenerate LP modes simultaneously, a mode multiplexer to utilize two-fold degenerate LP11 modes is proposed. It is composed of two consecutive LP11 MSCs that allows the multiplexing of LP01 mode and two orthogonal LP11 modes. We demonstrates WDM transmission of 30 wavelength channels with 33.3 GHz spacing, each carrying 3 modes, over 560 km of FMF. 6- mode multiplexer can multiplex 6 modes of LP01, LP11a, LP11b, LP21a, LP21b, LP02 modes. We demonstrated WDM-MDM transmission with the all-fiber 6-mode multiplexer. In this paper, the manufacturing method and the recent advancements of the all-fiber mode multiplexer based on the MSCs are reviewed. Long-distance mode division multiplexing (MDM) optical signal transmissions with the all-fiber mode multiplexer are experimentally demonstrated.

  19. High speed optical wireless data transmission system for particle sensors in high energy physics

    Science.gov (United States)

    Ali, W.; Corsini, R.; Ciaramella, E.; Dell'Orso, R.; Messineo, A.; Palla, F.

    2015-08-01

    High speed optical fiber or copper wire communication systems are frequently deployed for readout data links used in particle physics detectors. Future detector upgrades will need more bandwidth for data transfer, but routing requirements for new cables or optical fiber will be challenging due to space limitations. Optical wireless communication (OWC) can provide high bandwidth connectivity with an advantage of reduced material budget and complexity of cable installation and management. In a collaborative effort, Scuola Superiore Sant'Anna and INFN Pisa are pursuing the development of a free-space optical link that could be installed in a future particle physics detector or upgrade. We describe initial studies of an OWC link using the inner tracker of the Compact Muon Solenoid (CMS) detector as a reference architecture. The results of two experiments are described: the first to verify that the laser source transmission wavelength of 1550 nm will not introduce fake signals in silicon strip sensors while the second was to study the source beam diameter and its tolerance to misalignment. For data rates of 2.5 Gb/s and 10 Gb/s over a 10 cm working distance it was observed that a tolerance limit of ±0.25 mm to ±0.8 mm can be obtained for misaligned systems with source beam diameters of 0.38 mm to 3.5 mm, respectively.

  20. Transmission Techniques for Ultra Dense Wavelength Division Multiplexing By Using Two Optical Amplifiers in Nonlinear Optical Networks

    Directory of Open Access Journals (Sweden)

    Abd El-Naser A. Mohammed

    2010-09-01

    Full Text Available In the present paper, the problem amplification techniques of ultra dense wavelength division multiplexing (UDWDM in nonlinear optical networks are investigated through five transmission techniques. The impact of tailoring of chirped pulses of different temporal waveforms is investigated in a normal dispersion fiber. The set of multiplexed signals are tailored in a different a subset to assure approximately the same output level of power to hold the signal-to-noise ratio at the same level. Moreover, three different transmission techniques, namely, soliton propagation, maximum time division multiplexing (MTDM and ìShannonî capacity, are employed where successive section of alternating dispersion are used as a technique to manage the dispersion. Distributed ìRamanî amplifiers as well as Erbium doped fiber amplifier are engaged to maximize the repeater spacing. We have succeeded to multiplex 2400 (UDWDM channels in the optical range 1.45  1.65 µm with channel spacing ranging from 0.3 up to 0.6 nm where each channel has its own characteristic parameters of loss, dispersion, and amplification. The channels are divided into sub-groups ( each of 4, 5, 6, 7,Ö.,24 where the technique of space division multiplexing (SDM is applied. The multispan effects of ìKerrî nonlinearity and amplifier noise on ìShannonî channel capacity of dispersion-free nonlinear fiber is considered as a ceiling value for the sake of comparison. The case of soliton with modified Raman amplification via parametric gain also is investigated. Each link has special chemical structure, optical signals power, and optical Raman pumping. The cable contains {4, 5, 6, 7,Ö. , 24} links in SDM. It has been shown that the modified Raman gain yields higher effects on the variable under consideration if compared with the conventional Raman gain. The number of links is in positive correlations with the set of effects {Repeater spacing, Soliton product, MTDM product}. In general

  1. Achievable information rates calculation for optical OFDM few-mode fiber long-haul transmission systems.

    Science.gov (United States)

    Lin, Changyu; Djordjevic, Ivan B; Zou, Ding

    2015-06-29

    We propose a method to estimate the lower bound of achievable information rates (AIRs) of high speed orthogonal frequency-division multiplexing (OFDM) in spatial division multiplexing (SDM) optical long-haul transmission systems. The estimation of AIR is based on the forward recursion of multidimensional super-symbol efficient sliding-window Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm. We consider most of the degradations of fiber links including nonlinear effects in few-mode fiber (FMF). This method does not consider the SDM as a simple multiplexer of independent data streams, but provides a super-symbol version for AIR calculation over spatial channels. This super-symbol version of AIR calculation algorithm, in principle, can be used for arbitrary multiple-input-multiple-output (MIMO)-SDM system with channel memory consideration. We illustrate this method by performing Monte Carlo simulations in a complete FMF model. Both channel model and algorithm for calculation of the AIRs are described in details. We also compare the AIRs results for QPSK/16QAM in both single mode fiber (SMF)- and FMF-based optical OFDM transmission.

  2. Coherent light transmission properties of commercial photonic crystal hollow core optical fiber.

    Science.gov (United States)

    Cranch, G A; Miller, G A

    2015-11-01

    Photonic crystal hollow core fiber (PC-HCF) has enabled many exciting new applications in nonlinear optics and spectroscopy. However, to date there has been less impact in coherent applications where preservation of optical phase over long fiber lengths is crucial. This paper presents characteristics of three commercially available PC-HCFs relevant to coherent applications including higher-order mode analysis, birefringence and polarization-dependent loss, and their impact on coherent light transmission in PC-HCF. Multipath interference due to higher-order mode propagation and Fresnel reflection is shown to generate excess intensity noise in transmission, which can be suppressed by up to 20 dB through high frequency phase modulation of the source laser. To demonstrate the potential of PC-HCF in high performance sensing, a Mach-Zehnder interferometer (MZI) incorporating 10 m of PC-HCF in each arm is characterized and demonstrates a phase resolution (59×10(-9)  rad/Hz(1/2) at 30 kHz) close to the shot noise limit, which is better than can be achieved in a MZI made with the same length of single mode solid core fiber because of the limit set by fundamental thermodynamic noise (74×10(-9)  rad/Hz(1/2) at 30 kHz).

  3. Golay sequences coded coherent optical OFDM for long-haul transmission

    Science.gov (United States)

    Qin, Cui; Ma, Xiangrong; Hua, Tao; Zhao, Jing; Yu, Huilong; Zhang, Jian

    2017-09-01

    We propose to use binary Golay sequences in coherent optical orthogonal frequency division multiplexing (CO-OFDM) to improve the long-haul transmission performance. The Golay sequences are generated by binary Reed-Muller codes, which have low peak-to-average power ratio and certain error correction capability. A low-complexity decoding algorithm for the Golay sequences is then proposed to recover the signal. Under same spectral efficiency, the QPSK modulated OFDM with binary Golay sequences coding with and without discrete Fourier transform (DFT) spreading (DFTS-QPSK-GOFDM and QPSK-GOFDM) are compared with the normal BPSK modulated OFDM with and without DFT spreading (DFTS-BPSK-OFDM and BPSK-OFDM) after long-haul transmission. At a 7% forward error correction code threshold (Q2 factor of 8.5 dB), it is shown that DFTS-QPSK-GOFDM outperforms DFTS-BPSK-OFDM by extending the transmission distance by 29% and 18%, in non-dispersion managed and dispersion managed links, respectively.

  4. Secure Communications in High Speed Fiber Optical Networks Using Code Division Multiple Access (CDMA) Transmission

    Energy Technology Data Exchange (ETDEWEB)

    Han, I; Bond, S; Welty, R; Du, Y; Yoo, S; Reinhardt, C; Behymer, E; Sperry, V; Kobayashi, N

    2004-02-12

    This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple access (CDMA) is emerging as a bandwidth enhancing technique for fiber optic networks, (3) the realization that CDMA of sufficient complexity forms the basis for almost unbreakable one-time key transmissions, (4) our concepts for superior components for implementing CDMA, (5) our expertise in semiconductor device processing and (6) our Center for Nano and Microtechnology, which is where the majority of the experimental work was done. Here we present a novel device concept, which will push the limits of current technology, and will simultaneously solve system implementation issues by investigating new state-of-the-art fiber technologies. This will enable the development of secure communication systems for the transmission and reception of messages on deployed commercial fiber optic networks, through the CDMA phase encoding of broad bandwidth pulses. CDMA technology has been developed as a multiplexing technology, much like wavelength division multiplexing (WDM) or time division multiplexing (TDM), to increase the potential number of users on a given communication link. A novel application of the techniques created for CDMA is to generate secure communication through physical layer encoding. Physical layer encoding devices are developed which utilize semiconductor waveguides with fast carrier response times to phase encode spectral components of a secure signal. Current commercial technology, most commonly a spatial light modulator, allows phase codes to be changed at rates of only 10's of Hertz ({approx}25ms response). The use of fast (picosecond to nanosecond) carrier dynamics of semiconductors

  5. Safety analysis and realization of safe information transmission optical LAN on high-speed railway

    Science.gov (United States)

    Tao, Ying; Wu, Chongqing; Li, Zuoyi

    2001-10-01

    High-speed railway that has been progressing very quickly is one of the greatest techniques in present time because of its high speed, economy, comfort, environment benefits and other advantages. And among all of these, safe is the backbone and lifeline, so the chief task in developing high-speed railway is to establish safety guarantee system. Also in this safety guarantee system, train control is one of the key techniques to guarantee safe train operation and to advance ability of transportation, so operation safe is located in the hardcore position. That is to say, it is imperative to set up a safe, real-time and reliable automatic train control system. And we can easily find out that this kind of system is now developed and applied in many countries. Important information related to train control, such as the received and transmitted information of track-sided equipment, is called safe information, because it deals with train operation's safe, reliability, and even directly with people's life and wealth. It is so important that if there were some kind of fault with its making, transmission, or processing, fatal accident would occur. So to some degree, it is impossible to transmit and process this information through present railway communication network because of the former's extreme importance and the latter's no safe capability. Therefore, a specific communication network that mainly considers about safe transmission and management should be established in order to realize the specific function for this specific information. High-speed railway safe information transmission optical LAN, which adopts optical fiber as transmission media and transmits safe information, is a kind of LAN designed for the request for safe, real-time and highly reliable automatic train control system in the process of our country's high-speed railway construction and commonly train speed. In this paper, after analyzing the characteristics of automatic train control system and the

  6. Hobby-Eberly Telescope Optical Transmission Spectroscopy of the Hot Jupiter WASP-12b

    Science.gov (United States)

    Jensen, Adam G.; Redfield, Seth; Cauley, Paul W.; Endl, Michael; Cochran, William D.

    2017-01-01

    Transmission spectroscopy of exoplanetary atmospheres is an extremely useful tool that can be used for understanding exoplanetary composition as well as potentially revealing star-planet interactions from radiation, magnetic fields, and more. The hot Jupiter planet WASP-12b is interesting in that it is very close to its star (0.02 AU), has a large calculated scale height, has had water and metals detected in its atmosphere, and has had varying observational and theoretical constraints placed on its C/O ratio. Here we present a preliminary analysis of the optical transmission spectrum of WASP-12b taken with the Hobby-Eberly Telescope (HET). Our data covers the optical wavelength range from approximately 4800 to 6850 Angstroms. Most notably this includes two Balmer lines of hydrogen (H-alpha at 6563 Angstroms and H-beta at 4861 Angstroms) and the sodium D doublet (at 5890 and 5896 Angstroms). Due to the relative faintness of the system's central star and different instrumental settings, the analysis involves several challenges that are not present in previous transmission spectroscopy observations with the HET.This work is supported by NASA Exoplanet Research Program grant 14-XRP14_2-0090 to the University of Nebraska-Kearney. The Hobby-Eberly Telescope is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universitat Munchen, and Georg-August-Universitat Gottingen and is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly.

  7. Transmission test in connection of different types of optical fibers: a dispersion-shifted single-mode optical fiber (DSF) and a single-mode optical fiber (SM); DSF-SM ishu hikari fiber setsuzoku ni okeru denso shiken

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, J. [Chugoku Electric Power Co. Inc., Hiroshima (Japan)

    1998-08-25

    The currently used optical transmission system usually uses a single-mode optical fiber (SM) with 1.3 {mu} m band. For sections requiring long-distance transmission, a dispersion-shifted single-mode optical fiber (DSF) with 1.55 {mu} m band is beginning to be partly used. If, in using these fibers, the different types of optical fibers, SM and DSF, can be used directly connected with each other, structuring an economical optical communication network including the existing SM fibers may become possible. This paper describes measurements of connection loss between the different optical fibers of DSF and SM, a transmission test on the connection between the different optical fibers of DSF and SM by using an amplifier for optical fibers used in an actual field, and an optical wave multiplex transmission test. The measurements and the tests were carried out in winter and summer of 1997 by using the existing OPGW optical fibers among the Okayama substation, the Higashi-Okayama substation, and the Susai substation. The connection between the different optical fibers of DSF and SM generates greater connection loss than in connection with the same type of fibers due to difference in the mode field diameters. Therefore, it will be necessary in constituting an optical fiber line to incorporate connection loss of about 1 to 2 dB in connector connection and about 0.5 to 1 dB in welding connection. 1 ref., 17 figs., 7 tabs.

  8. Study of lineal and non-lineal transmission of an optical fiber Sagnac interferometer as a bidirectional device

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Beltran, J [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias de la Electronica (Mexico); Beltran-Perez, G; Castillo-Mixcoatl, J; Munoz-Aguirre, S [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Fisco-Matematicas (Mexico); Zaca-Moran, P [Benemerita Universidad Autonoma de Puebla, Fisicoquimica de Materiales, ICUAP (Mexico); Felipe, C, E-mail: squall_rb@hotmail.com [Departamento de biociencias e ingenieria, CIIEMAD, Instituto Politecnico Nacional (Mexico)

    2011-01-01

    The optical fiber Sagnac interferometer is a versatile system that has been investigated for a variety of applications such as optical switchers, filters, demultiplexers and passive mode-locked laser. In many cases, this arrangement is designed using a symmetrical coupler with two of their ports connected making a loop and generally the analysis have been focused in the transmission of the signal propagated in only one direction. Therefore in the present work a complementary study of the system considering the analysis for the lineal and non-lineal transmission as a bidirectional device has been performed. The experimental setup consists of different optical fiber lengths inside the cavity loop (between 100 and 500 m) with highly twisted singlemode fiber, a quarter wave retarder placed asymmetrically in one arm and a 50/50 coupler. The results have shown that for low optical powers, it is possible to adjust the system transmission in both propagation directions with the rotation of the retarder wave. On the other hand, in high optical power levels, this arrangement showed that the transmission increases slowly for the case when both the input and the output beams have the same polarization. This behavior can be used for pedestal suppression in a light pulse. Furthermore, for the case when the output signal polarization is orthogonal respect to the input one, the transmission changes quite fast. This effect can be used for applications such as the passive mode-locking.

  9. Study of Lineal and Non-Lineal Transmission of AN Optical Fiber Sagnac Interferometer as a Bidirectional Device

    Science.gov (United States)

    Ramos-Beltrán, J.; Beltrán-Pérez, G.; Castillo-Mixcóatl, J.; Muñoz-Aguirre, S.; Zaca-Morán, P.; Felipe, C.

    2011-01-01

    The optical fiber Sagnac interferometer is a versatile system that has been investigated for a variety of applications such as optical switchers, filters, demultiplexers and passive mode-locked laser. In many cases, this arrangement is designed using a symmetrical coupler with two of their ports connected making a loop and generally the analysis have been focused in the transmission of the signal propagated in only one direction. Therefore in the present work a complementary study of the system considering the analysis for the lineal and non-lineal transmission as a bidirectional device has been performed. The experimental setup consists of different optical fiber lengths inside the cavity loop (between 100 and 500 m) with highly twisted singlemode fiber, a quarter wave retarder placed asymmetrically in one arm and a 50/50 coupler. The results have shown that for low optical powers, it is possible to adjust the system transmission in both propagation directions with the rotation of the retarder wave. On the other hand, in high optical power levels, this arrangement showed that the transmission increases slowly for the case when both the input and the output beams have the same polarization. This behavior can be used for pedestal suppression in a light pulse. Furthermore, for the case when the output signal polarization is orthogonal respect to the input one, the transmission changes quite fast. This effect can be used for applications such as the passive mode-locking.

  10. Fiber Transmission Stabilization by Optical Heterodyning Techniques and Synchronization of Mode-Locked Lasers Using Two Spectral Lines

    CERN Document Server

    Staples, J W

    2005-01-01

    Stabilization of the transit time through a glass fiber using an optical heterodyne technique promises to provide jitter reduction down to the few femtosecond level using inexpensive commodity hardware. An acousto-optical frequency shifter provides the optical frequency offset that is used to downconvert phase shifts at optical frequency to equivalent phase shifts at radio frequency which are used to close a phase-lock loop driving a piezoelectric phase shifter. Using the stabilized fiber transmission medium, two spectral lines of a mode locked laser lock two low-power CW lasers which are transmitted to a receiver which phase locks the same spectral lines of a second mode-locked laser to the first. The optical transmission system operates at low power and is linear, providing excellent signal-to-noise ratio and allows many signals to be transmitted without mutual interference. Experimental results will be presented.

  11. Elucidating gigahertz acoustic modulation of extraordinary optical transmission through a two-dimensional array of nano-holes

    Science.gov (United States)

    Ulbricht, R.; Sakuma, H.; Imade, Y.; Otsuka, P. H.; Tomoda, M.; Matsuda, O.; Kim, H.; Park, G.-W.; Wright, O. B.

    2017-02-01

    The ultrafast modulation of light transmitted by a metamaterial making up an extraordinary optical transmission geometry is investigated by means of optical pump-probe spectroscopy. Using a sample consisting of a lattice of square nano-holes in a gold film on a glass substrate, we monitor the high-frequency oscillations in the intensity of transmitted infrared light. A variety of gigahertz acoustic modes, involving the opening and shutting motion of the holes as well as the straining of the glass substrate below the holes, are revealed to be active in the optical modulation. Numerical simulations of the transient deformations and strain fields elucidate the nature of the vibrational modes contributing most strongly to the variations in optical transmission, and point to the hole-area modulation as the dominant effect. Potential applications include ultrafast acousto-optic modulators.

  12. An optical study of amorphous (Se80Te20)100-xGex thin films using their transmission spectra

    Science.gov (United States)

    Mainika; Sharma, Pankaj; Katyal, S. C.; Thakur, Nagesh

    2008-12-01

    Optical constants (refractive index and extinction coefficient) have been studied for a-(Se80Te20)100-xGex (x = 0, 2, 4, 6) thin films using transmission spectra in the wavelength range 500 2500 nm. It is observed from optical transmission measurements that the optical energy gap (Eg) increases while the refractive index (n) and the extinction coefficient (k) decrease with the incorporation of Ge in the Se Te system. The increase in the optical energy gap is interpreted by correlating the optical energy gap with the decrease in electronegativity and increase in the heat of atomization (Hs). The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple DiDomenico model.

  13. Nonlinear and magneto-optical transmission studies on magnetic nanofluids of non-interacting metallic nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Reena Mary, A P; Anantharaman, M R [Department of Physics, Cochin University of Science and Technology, Cochin 682 022 (India); Suchand Sandeep, C S; Philip, Reji [Light and Matter Physics Group, Raman Research Institute, Sadashivanagar, Bangalore-560080 (India); Narayanan, T N; Moloney, Padraig; Ajayan, P M, E-mail: reji@rri.res.in, E-mail: mraiyer@yahoo.com [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX-77005 (United States)

    2011-09-16

    Oxide free stable metallic nanofluids have the potential for various applications such as in thermal management and inkjet printing apart from being a candidate system for fundamental studies. A stable suspension of nickel nanoparticles of {approx} 5 nm size has been realized by a modified two-step synthesis route. Structural characterization by x-ray diffraction and transmission electron microscopy shows that the nanoparticles are metallic and are phase pure. The nanoparticles exhibited superparamagnetic properties. The magneto-optical transmission properties of the nickel nanofluid (Ni-F) were investigated by linear optical dichroism measurements. The magnetic field dependent light transmission studies exhibited a polarization dependent optical absorption, known as optical dichroism, indicating that the nanoparticles suspended in the fluid are non-interacting and superparamagnetic in nature. The nonlinear optical limiting properties of Ni-F under high input optical fluence were then analyzed by an open aperture z-scan technique. The Ni-F exhibits a saturable absorption at moderate laser intensities while effective two-photon absorption is evident at higher intensities. The Ni-F appears to be a unique material for various optical devices such as field modulated gratings and optical switches which can be controlled by an external magnetic field.

  14. Dichoptic Metacontrast Masking Functions to Infer Transmission Delay in Optic Neuritis

    Science.gov (United States)

    Bruchmann, Maximilian; Korsukewitz, Catharina; Krämer, Julia; Wiendl, Heinz; Meuth, Sven G.

    2016-01-01

    Optic neuritis (ON) has detrimental effects on the transmission of neuronal signals generated at the earliest stages of visual information processing. The amount, as well as the speed of transmitted visual signals is impaired. Measurements of visual evoked potentials (VEP) are often implemented in clinical routine. However, the specificity of VEPs is limited because multiple cortical areas are involved in the generation of P1 potentials, including feedback signals from higher cortical areas. Here, we show that dichoptic metacontrast masking can be used to estimate the temporal delay caused by ON. A group of 15 patients with unilateral ON, nine of which had sufficient visual acuity and volunteered to participate, and a group of healthy control subjects (N = 8) were presented with flashes of gray disks to one eye and flashes of gray annuli to the corresponding retinal location of the other eye. By asking subjects to report the subjective visibility of the target (i.e. the disk) while varying the stimulus onset asynchrony (SOA) between disk and annulus, we obtained typical U-shaped masking functions. From these functions we inferred the critical SOAmax at which the mask (i.e. the annulus) optimally suppressed the visibility of the target. ON-associated transmission delay was estimated by comparing the SOAmax between conditions in which the disk had been presented to the affected and the mask to the other eye, and vice versa. SOAmax differed on average by 28 ms, suggesting a reduction in transmission speed in the affected eye. Compared to previously reported methods assessing perceptual consequences of altered neuronal transmission speed the presented method is more accurate as it is not limited by the observers’ ability to judge subtle variations in perceived synchrony. PMID:27711139

  15. Optical fiber sources and transmission controls for multi-Tb/s systems

    Science.gov (United States)

    Nowak, George Adelbert

    The accelerating demand for bandwidth capacity in backbone links of terrestrial communications systems is projected to exceed 1Tb/s by 2002. Lightwave carrier frequencies and fused-silica optical fibers provide the natural combination of high passband frequencies and low- loss medium to satisfy this evolving demand for bandwidth capacity. This thesis addresses three key technologies for enabling multi-Tb/s optical fiber communication systems. The first technology is a broadband source based on supercontinuum generation in optical fiber. Using a single modelocked laser with output pulsewidths of 0.5psec pulses, we generate in ~2m of dispersion-shifted fiber more that 200nm of spectral continuum in the vicinity of 1550nm that is flat to better than +/- 0.5 dB over more than 60nm. The short fiber length prevents degradation of timing jitter of the seed pulses and preserves coherence of the continuum by inhibiting environmental perturbations and mapping of random noise from the vicinity of the input pulse across the continuum. Through experiments and simulations, we find that the continuum characteristics result from 3rd order dispersion effects on higher-order soliton compression. We determine optimal fiber properties to provide desired continuum broadness and flatness for given input pulsewidth and energy conditions. The second technology is a novel delay-shifted nonlinear optical loop mirror (DS-NOLM) that performs a transmission control function by serving as an intensity filter and frequency compensator for 4ps soliton transmission over 75km of standard dispersion fiber, with 25km spacing between amplifiers, by filtering the dispersive waves and compensating for Raman-induced soliton self-frequency shift. The third technology is all-fiber wavelength conversion employing induced modulational instability. We obtain wavelength conversion over 40nm with a peak conversion efficiency of 28dB using 600mW pump pulses in 720m of high-nonlinearity optical fiber. We show

  16. Biomimetic hairy surfaces as superhydrophobic highly transmissive films for optical applications (Conference Presentation)

    Science.gov (United States)

    Vuellers, Felix; Gomard, Guillaume; Preinfalk, Jan B.; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce S.; Hölscher, Hendrik; Kavalenka, Maryna N.

    2017-02-01

    Combining high optical transmission, water-repellency and self-cleaning is of great interest for optoelectronic devices operating in outdoor conditions, such as photovoltaics where shading can significantly reduce the power output. The surface of water plant Pistia stratiotes combines these functionalities through a dense layer of transparent microhairs. It renders the surface superhydrophobic without affecting absorption of sunlight necessary for photosynthesis. Inspired by this surface, we fabricated a superhydrophobic flexible thin nanofur film made from optical grade polycarbonate using a scalable combination of hot embossing and hot pulling techniques. During fabrication, heated sandblasted steel plates locally elongate softened polymer, thus covering its surface in microcavities surrounded by high aspect ratio micro- and nanohairs. The superhydrophobic nanofur exhibits contact angles of (166+/-6°), low sliding angles (film stands above 85% over the visible range, with 97% of the transmitted light scattered forward. Reflection drops below 4% when coated on a polymeric substrate, which can enhance light extraction in organic light emitting diodes (OLEDs). We report an increase of more than 10% in luminous efficacy for a nanofur coated OLED compared to a bare device. Finally, the nanofur film can be used for enhancing the incoupling of light to solar cells, while additionally providing self-cleaning properties. Optical coupling of the nanofur to a multi-crystalline silicon solar cell results in a 5.8% gain in photocurrent compared to a bare device under normal incidence.

  17. Transmission in near-infrared optical windows for deep brain imaging.

    Science.gov (United States)

    Shi, Lingyan; Sordillo, Laura A; Rodríguez-Contreras, Adrián; Alfano, Robert

    2016-01-01

    Near-infrared (NIR) radiation has been employed using one- and two-photon excitation of fluorescence imaging at wavelengths 650-950 nm (optical window I) for deep brain imaging; however, longer wavelengths in NIR have been overlooked due to a lack of suitable NIR-low band gap semiconductor imaging detectors and/or femtosecond laser sources. This research introduces three new optical windows in NIR and demonstrates their potential for deep brain tissue imaging. The transmittances are measured in rat brain tissue in the second (II, 1,100-1,350 nm), third (III, 1,600-1,870 nm), and fourth (IV, centered at 2,200 nm) NIR optical tissue windows. The relationship between transmission and tissue thickness is measured and compared with the theory. Due to a reduction in scattering and minimal absorption, window III is shown to be the best for deep brain imaging, and windows II and IV show similar but better potential for deep imaging than window I.

  18. Spectroscopic studies of atomic and molecular species relevant to the optical fibre transmission bands

    CERN Document Server

    Meldau, J

    1995-01-01

    The work presented in this thesis, although all relevant to wavelength standards in the optical fibre transmission windows at 1.3 mu m and 1.55 mu m, can be split into three main parts. Firstly, the work carried out at the University of Strathclyde concerning accurate line position measurements of some molecules having absorption bands at 1.5 mu m ( sup 1 sup 5 NH sub 3 , C sub 2 H sub 2 and sup 1 sup 3 C sup 1 sup 2 CH sub 2) and 1.3 mu m ( sup 1 sup 3 C sub 2 D-2 and sup 1 sup 2 C sub 2 D sub 2) with a Fourier transform spectrometer (FTS). The FTS measurements were undertaken primarily to provide a comprehensive list of fairly strong lines relevant to the optical fibre regions as potential wavelength references for the National Physical Laboratory (NPL). The sup 1 sup 3 C sup 1 sup 2 CH sub 2 overtone and combination bands were assigned and fitted. Secondly, the development of two diode laser spectrometers was carried out at the University of Strathclyde to perform an optical double resonance experiment in ...

  19. A training-aided MIMO equalization based on matrix transformation in the space division multiplexed fiber-optic transmission system

    Science.gov (United States)

    Guan, Xiaoning; Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Tian, Qinghua; Zhang, Qi; Tian, Feng; Li, Dengao; Zhao, Jumin; Wang, Renfan

    2016-10-01

    A novel training sequence is designed for the space division multiplexed fiber-optic transmission system in this paper. The training block is consisting of segmented sequence, which can be used to compensate time offset and distortion (such as dispersion) in the transmission link. The channel function can be obtained by one tap equalization in the receiver side. This paper designs the training sequence by adjusting the length of the training signals and implementing matrix transformation, to obtain the coefficient of equalizer for channel detect and equalization. This new training sequence reduces system complexity and improves transmission efficiency at the same time. Compared with blind equalization, the matrix transformation based training sequence can reduce system complexity, and perform targeted equalization to the mechanism of mode coupling in the space division optical fiber system. As a result, it can effectively improve signal transmission quality and reduce bit error rate.

  20. Channel Measurements for a Optical Fiber-Wireless Transmission System in the 75-110 GHz Band

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Yu, Xianbin; Zhao, Ying;

    2011-01-01

    We report on measured optical fiber W-band wireless channel characteristics such as frequency response, channel loss and fading, directivity, channel capacity and phase noise. Our proposed system performs a sextuple frequency up-conversion after 20 km of fiber transmission, followed by a W......-band wireless link. Our experimental measurements are intended to provide engineering rules for designing hybrid multi-gigabit W band transmission links....

  1. Doubling transmission capacity in optical wireless system by antenna horizontal- and vertical-polarization multiplexing.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Zhang, Junwen; Dong, Ze; Chi, Nan

    2013-06-15

    We experimentally demonstrate 2×56 Gb/s two-channel polarization-division-multiplexing quadrature-phase-shift-keying signal delivery over 80 km single-mode fiber-28 and 2 m Q-band (33-50 GHz) wireless link, adopting antenna horizontal- (H-) and vertical-polarization (V-polarization) multiplexing. At the wireless receiver, classic constant-modulus-algorithm equalization based on digital signal processing can realize polarization demultiplexing and remove the crosstalk at the same antenna polarization. By adopting antenna polarization multiplexing, the signal baud rate and performance requirements for optical and wireless devices can be reduced but at the cost of double antennas and devices, while wireless transmission capacity can also be increased but at the cost of stricter requirements for V-polarization. The isolation is only about 19 dB when V-polarization deviation approaches 10°, which will affect high-speed (>50 Gb/s) wireless delivery.

  2. Performance Enhancement of Optical CDMA by Differential-Phase Method for Radio-over-Fiber Transmissions

    Directory of Open Access Journals (Sweden)

    Hsu-Chih Cheng

    2013-01-01

    Full Text Available The study proposes the differential-phase optical code-division multiple-access (OCDMA network for radio-over-fiber (RoF transmissions, and the characteristics are numerically analyzed. The network coder/decoders (codecs are structured on the basis of arrayed-waveguide-grating (AWG routers with complementary Walsh-Hadamard (CWH signature codes. In the proposed system, the network requires only two AWG routers to accomplish spectral encoding of radio base station (RBS and decoding of control station for the complementary keying, thus resulting in a simpler and low cost system. Performance analyses are evaluated with the dominant noise of phase-induced intensity noise (PIIN in spectral code OCDMA network. By the proposed AWG-based OCDMA with the differential-phase scheme, it is possible to establish interference-free and low crosstalk beat noise RoF systems.

  3. Achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping.

    Science.gov (United States)

    Semrau, Daniel; Xu, Tianhua; Shevchenko, Nikita A; Paskov, Milen; Alvarado, Alex; Killey, Robert I; Bayvel, Polina

    2017-01-01

    Achievable information rates (AIRs) of wideband optical communication systems using a ∼40  nm (∼5  THz) erbium-doped fiber amplifier and ∼100  nm (∼12.5  THz) distributed Raman amplification are estimated based on a first-order perturbation analysis. The AIRs of each individual channel have been evaluated for DP-64QAM, DP-256QAM, and DP-1024QAM modulation formats. The impact of full-field nonlinear compensation (FF-NLC) and probabilistically shaped constellations using a Maxwell-Boltzmann distribution were studied and compared to electronic dispersion compensation. It has been found that a probabilistically shaped DP-1024QAM constellation, combined with FF-NLC, yields achievable information rates of ∼75  Tbit/s for the EDFA scheme and ∼223  Tbit/s for the Raman amplification scheme over a 2000 km standard single-mode fiber transmission.

  4. An optical transmission spectrum of the giant planet WASP-36 b

    CERN Document Server

    Mancini, L; Southworth, J; Bott, K; Mollière, P; Ciceri, S; Chen, G; Henning, Th

    2016-01-01

    We present broad-band photometry of five transits in the planetary system WASP-36, totaling 17 high-precision light curves. Four of the transits were simultaneously observed in four passbands (g, r, i, z), using the telescope-defocussing technique, and achieving scatters of less than 1 mmag per observation. We used these data to improve the measured orbital and physical properties of the system, and obtain an optical transmission spectrum of the planet. We measured a decreasing radius from bluer to redder passbands with a confidence level of more than 5 sigma. The radius variation is roughly 11 pressure scale heights between the g and the z bands. This is too strong to be Rayleigh scattering in the planetary atmosphere, and implies the presence of a species which absorbs strongly at bluer wavelengths.

  5. Full-field optical thickness profilometry of semitransparent thin films with transmission densitometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jay; Harris, Tequila

    2010-05-20

    A novel bidirectional thickness profilometer based on transmission densitometry was designed to measure the localized thickness of semitransparent films on a dynamic manufacturing line. The densitometer model shows that, for materials with extinction coefficients between 0.3 and 2.9 D/mm, 100-500 {mu}m measurements can be recorded with less than {+-}5% error at more than 10,000 locations in real time. As a demonstration application, the thickness profiles of 75 mmx100 mm regions of polymer electrolyte membrane (PEM) were determined by converting the optical density of the sample to thickness with the Beer-Lambert law. The PEM extinction coefficient was determined to be 1.4 D/mm, with an average thickness error of 4.7%.

  6. 32 x 10 and 64 × 10 Gb/s transmission using hybrid Raman-Erbium doped optical amplifiers

    Directory of Open Access Journals (Sweden)

    Shveta Singh

    2011-08-01

    Full Text Available We have successfully demonstrated a long-haul transmission of 32 × 10 Gbit/s and 64 × 10 Gbit/s over single-mode fiber of 650 km and 530 km respectively by using RAMAN-EDFA hybrid optical amplifier as inline and preamplifier amplifiers. The measured Q-factors and BER of the 32 and 64 channels after 650 and 530 km respectively (16.99–17 dB and (10-13 were higher than the standard acceptable value, which offers feasibility of the hybrid amplifiers including EDFA optical amplifiers for the long-haul transmission.

  7. Optical transmission radiation damage and recovery stimulation of DSB: Ce3+ inorganic scintillation material

    Science.gov (United States)

    Borisevich, A.; Dormenev, V.; Korjik, M.; Kozlov, D.; Mechinsky, V.; Novotny, R. W.

    2015-02-01

    Recently, a new scintillation material DSB: Ce3+ was announced. It can be produced in a form of glass or nano-structured glass ceramics with application of standard glass production technology with successive thermal annealing. When doped with Ce3+, material can be applied as scintillator. Light yield of scintillation is near 100 phe/MeV. Un-doped material has a wide optical window from 4.5eV and can be applied to detect Cherenkov light. Temperature dependence of the light yield LY(T) is 0.05% which is 40 times less than in case of PWO. It can be used for detectors tolerant to a temperature variation between -20° to +20°C. Several samples with dimensions of 15x15x7 mm3 have been tested for damage effects on the optical transmission under irradiation with γ-quanta. It was found that the induced absorption in the scintillation range depends on the doping concentration and varies in range of 0.5-7 m-1. Spontaneous recovery of induced absorption has fast initial component. Up to 25% of the damaged transmission is recuperated in 6 hours. Afterwards it remains practically constant if the samples are kept in the dark. However, induced absorption is reduced by a factor of 2 by annealing at 50°C and completely removed in a short time when annealing at 100°C. A significant acceleration of the induced absorption recovery is observed by illumination with visible and IR light. This effect is observed for the first time in a Ce-doped scintillation material. It indicates, that radiation induced absorption in DSB: Ce scintillation material can be retained at the acceptable level by stimulation with light in a strong irradiation environment of collider experiments.

  8. Performances and reliability predictions of optical data transmission links using a system simulator for aerospace applications

    Science.gov (United States)

    Bechou, L.; Deshayes, Y.; Aupetit-Berthelemot, C.; Guerin, A.; Tronche, C.

    Space missions for Earth Observation are called upon to carry a growing number of instruments in their payload, whose performances are increasing. Future space systems are therefore intended to generate huge amounts of data and a key challenge in coming years will therefore lie in the ability to transmit that significant quantity of data to ground. Thus very high data rate Payload Telemetry (PLTM) systems will be required to face the demand of the future Earth Exploration Satellite Systems and reliability is one of the major concern of such systems. An attractive approach associated with the concept of predictive modeling consists in analyzing the impact of components malfunctioning on the optical link performances taking into account the network requirements and experimental degradation laws. Reliability estimation is traditionally based on life-testing and a basic approach is to use Telcordia requirements (468GR) for optical telecommunication applications. However, due to the various interactions between components, operating lifetime of a system cannot be taken as the lifetime of the less reliable component. In this paper, an original methodology is proposed to estimate reliability of an optical communication system by using a dedicated system simulator for predictive modeling and design for reliability. At first, we present frameworks of point-to-point optical communication systems for space applications where high data rate (or frequency bandwidth), lower cost or mass saving are needed. Optoelectronics devices used in these systems can be similar to those found in terrestrial optical network. Particularly we report simulation results of transmission performances after introduction of DFB Laser diode parameters variations versus time extrapolated from accelerated tests based on terrestrial or submarine telecommunications qualification standards. Simulations are performed to investigate and predict the consequence of degradations of the Laser diode (acting as a

  9. Dispersion compensation of fiber Bragg gratings in 3100 km high speed optical fiber transmission system

    Institute of Scientific and Technical Information of China (English)

    Li PEI; Tigang NING; Fengping YAN; Xiaowei DONG; Zhongwei TAN; Yan LIU; Shuisheng JIAN

    2009-01-01

    By optimizing the fabrication process of the chirped optical fiber Bragg grating (CFBG), some key problems of CFBG are solved, such as fabrication repetition, temperature stability, group delay ripple (GDR), fluctuation of the reflection spectrum, polarization mode dispersion (PMD), interaction of cascaded CFBG, and so on. The CFBG we fabricated can attain a temperature coefficient less than 0.0005 nm/℃, and the smoothed GDR and the fluctuation of the reflection spectrum are smaller than 10ps and 0.5dB, respec-tively. The PMD of each CFBG is less than 1 ps and the dispersion of each grating is larger than -2600 ps/(nm·km). With dispersion compensated by the CFBGs we fabricated, a 13×10 Gbit/s 3100 km ultra long G.652 fiber transmission system is successfully imple-mented without electric regenerator. The bit error rate (BER) of the system is below 10-4 without forward error correction (FEC); when FEC is added, the BER is below 10-12. The power penalty of the carrier-suppressed return-to-zero (CSRZ) code transmission system is only 2.5 dB.

  10. A Ground-based Optical Transmission Spectrum of WASP-6b

    CERN Document Server

    Jordán, Andrés; Rabus, Markus; Eyheramendy, Susana; Sing, David K; Désert, Jean-Michel; Bakos, Gáspár Á; Fortney, Jonathan J; López-Morales, Mercedes; Maxted, Pierre F L; Triaud, Amaury H M J; Szentgyorgyi, Andrew

    2013-01-01

    We present a ground based optical transmission spectrum of the inflated sub-Jupiter mass planet WASP-6b. The spectrum was measured in twenty spectral channels from 480 nm to 860nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the IMACS spectrograph on the Baade telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars, and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensat...

  11. Effects of ultraviolet nanosecond laser irradiation on structural modification and optical transmission of single layer graphene

    Science.gov (United States)

    Li, Chunhong; Kang, Xiaoli; Zhu, Qihua; Zheng, Wanguo

    2017-03-01

    Structural modifications and optical transmission change of single layer graphene (SLG) on transparent SiO2 substrate induced by nanosecond 355 nm laser irradiation were systematically studied by scanning electron microscopy (SEM), laser-excited Raman, X-ray photon spectroscopy (XPS) and UV-vis transmission spectra. In this study, to avoid damage to graphene, the selected irradiation fluence was set to be smaller than the laser damage threshold of SLG. Laser-driven formation of nano-dots, carbon clusters and spherical carbon morphologies were clearly presented using SEM magnification images, and the formation mechanism of such structures were discussed. Raman spectra revealed formation of D' peak and the continuously increasing of ID/IG intensity ratio with the concurrent increase of laser fluence, indicating the increase in amount of structural defects and disordering in SLG. XPS results disclosed that the oxygen content in SLG increases with laser fluence. The formation and relative content increase of Cdbnd O, Csbnd Osbnd C and Osbnd Cdbnd O bonds in SLG induced by laser irradiation were also revealed by XPS. Laser-driven micro-structure modifications of crystalline graphene to nano-crystalline graphene and photo-chemical reactions between graphene and O2 and H2O in air environment were suggested to be responsible for the Raman and XPS revealed modifications in SLG. It is worthy to point out that the above mentioned structural modifications only caused a slight decrease (graphene aiming at modifying its structure and thus taiorling its properties.

  12. Effect of Rain Attenuations on Free Space Optic Transmission in Kuala Lumpur

    Directory of Open Access Journals (Sweden)

    Fatin Hamimi Mustafa

    2011-01-01

    Full Text Available This research paper describes the effects of rain attenuation on the free space optical (FSO transmission system. The entire research was conducted in the heart of Kuala Lumpur city- year 2001, as the city was using such systems (LAN-to-LAN & WLAN-to-WLAN widely to connect the metropolitan areas for data transmission. The preliminary experiments were done using PAVLight product modeled PL-1G/1Tx/GigE which leaded to maximum reach of 700m distance with 810nm wavelength and also laser power of 14dBm. The data for rain intensities were obtained from measuring unit at UTM Jalan Semarak, Kuala Lumpur following the ITU protocols such as ITU-R P.1814 and ITU-R P.1817. The transmission and reception were achieved by using Continuous Wave (CW Laser signals as transmitting signals and APD photo detector to receive it on the other end. The experiments were fully carried out for two conditions (heavy-rain and lighter rain or drizzle with multiple repetitions. At last, the collected data were compiled and compared with other researcher's results. It was found to be the same as how the other researchers have obtained before for various cities worldwide. The results were found to be very satisfactory. It obeyed the theoretical aspects as higher the rain, higher the attenuations then. These results the degradation on the received signals. As a guide for future implementation of FSO systems for various atmospheric conditions in the metropolitan areas of Kuala Lumpur; we believed that this preliminary works may help.

  13. Investigations of high-speed optical transmission systems employing Absolute Added Correlative Coding (AACC)

    Science.gov (United States)

    Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin

    2016-07-01

    A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ˜-28.3 dBm and ˜336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.

  14. Further constraints on the optical transmission spectrum of HAT-P-1b

    CERN Document Server

    Montalto, M; Santos, N C; Desidera, S; Martins, J H C; Figueira, P; Alonso, R; .,

    2015-01-01

    We report on novel observations of HAT-P-1 aimed at constraining the optical transmission spectrum of the atmosphere of its transiting Hot-Jupiter exoplanet. Ground-based differential spectrophotometry was performed over two transit windows using the DOLORES spectrograph at the Telescopio Nazionale Galileo (TNG). Our measurements imply an average planet to star radius ratio equal to $\\rm R_p/R_{\\star}$=(0.1159$\\pm$0.0005). This result is consistent with the value obtained from recent near infrared measurements of this object but differs from previously reported optical measurements being lower by around 4.4 exoplanet scale heights. Analyzing the data over 5 different spectral bins 600\\AA$\\,$ wide we observed a single peaked spectrum (3.7 $\\rm\\sigma$ level) with a blue cut-off corresponding to the blue edge of the broad absorption wing of sodium and an increased absorption in the region in between 6180-7400\\AA. We also infer that the width of the broad absorption wings due to alkali metals is likely narrower t...

  15. Tele-transmission of stereoscopic images of the optic nerve head in glaucoma via Internet.

    Science.gov (United States)

    Bergua, Antonio; Mardin, Christian Y; Horn, Folkert K

    2009-06-01

    The objective was to describe an inexpensive system to visualize stereoscopic photographs of the optic nerve head on computer displays and to transmit such images via the Internet for collaborative research or remote clinical diagnosis in glaucoma. Stereoscopic images of glaucoma patients were digitized and stored in a file format (joint photographic stereoimage [jps]) containing all three-dimensional information for both eyes on an Internet Web site (www.trizax.com). The size of jps files was between 0.4 to 1.4 MB (corresponding to a diagonal stereo image size between 900 and 1400 pixels) suitable for Internet protocols. A conventional personal computer system equipped with wireless stereoscopic LCD shutter glasses and a CRT-monitor with high refresh rate (120 Hz) can be used to obtain flicker-free stereo visualization of true-color images with high resolution. Modern thin-film transistor-LCD displays in combination with inexpensive red-cyan goggles achieve stereoscopic visualization with the same resolution but reduced color quality and contrast. The primary aim of our study was met to transmit stereoscopic images via the Internet. Additionally, we found that with both stereoscopic visualization techniques, cup depth, neuroretinal rim shape, and slope of the inner wall of the optic nerve head, can be qualitatively better perceived and interpreted than with monoscopic images. This study demonstrates high-quality and low-cost Internet transmission of stereoscopic images of the optic nerve head from glaucoma patients. The technique allows exchange of stereoscopic images and can be applied to tele-diagnostic and glaucoma research.

  16. Nanoscale chromatin structure characterization for optical applications: a transmission electron microscopy study (Conference Presentation)

    Science.gov (United States)

    Li, Yue; Cherkezyan, Lusik; Zhang, Di; Almassalha, Luay; Roth, Eric; Chandler, John; Bleher, Reiner; Subramanian, Hariharan; Dravid, Vinayak P.; Backman, Vadim

    2017-02-01

    Structural and biological origins of light scattering in cells and tissue are still poorly understood. We demonstrate how this problem might be addressed through the use of transmission electron microscopy (TEM). For biological samples, TEM image intensity is proportional to mass-density, and thus proportional to refractive index (RI). By calculating the autocorrelation function (ACF) of TEM image intensity of a thin-section of cells, we essentially maintain the nanoscale ACF of the 3D cellular RI distribution, given that the RI distribution is statistically isotropic. Using this nanoscale 3D RI ACF, we can simulate light scattering through biological samples, and thus guiding many optical techniques to quantify specific structures. In this work, we chose to use Partial Wave Spectroscopy (PWS) microscopy as a one of the nanoscale-sensitive optical techniques. Hela cells were prepared using standard protocol to preserve nanoscale ultrastructure, and a 50-nm slice was sectioned for TEM imaging at 6 nm resolution. The ACF was calculated for chromatin, and the PWS mean sigma was calculated by summing over the power spectral density in the visible light frequency of a random medium generated to match the ACF. A 1-µm slice adjacent to the 50-nm slice was sectioned for PWS measurement to guarantee identical chromatin structure. For 33 cells, we compared the calculated PWS mean sigma from TEM and the value measured directly, and obtained a strong correlation of 0.69. This example indicates the great potential of using TEM measured RI distribution to better understand the quantification of cellular nanostructure by optical methods.

  17. Single-channel 1.28 Tbit/s-525 km DQPSK transmission using ultrafast time-domain optical Fourier transformation and nonlinear optical loop mirror

    DEFF Research Database (Denmark)

    Guan, Pengyu; Mulvad, Hans Christian Hansen; Tomiyama, Yutaro

    2011-01-01

    developed an ultrafast timedomain optical Fourier transformation technique in a round-trip configuration. By applying this technique to subpicosecond pulses, transmission impairments were greatly reduced, and BER performance below FEC limit was obtained with increased system margin. Copyright © 2011...

  18. A Study on the Development and Application of Monitoring System for Power Transmission Facilities by using the Optical Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.J.; Cho, H.K.; Han, M.S.; Kim, S.K.; Oh, M.T; Park, K.J.; Kim, W.K. [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Park, H.K.; Kim, N.; Ban, J.K.; Song, W.Y.; Park, S.K.; Lee, S.Y.; Lee, K.Y.; Lee, Y.H.; Yoon, J.H.; Kim, S.T. [Electrical Engineering and Science Research Center (Korea, Republic of)

    1993-12-31

    Corresponding to extended scope of transmission line maintenance and surveillance system, complex and long transmission line, high capacity and diversutt of monitoring information owing to bulky and high voltage of the system, there have been great demands for new measurement and communication technology on maintenance and monitoring of transmission line facilities. Henceforth in the field of large scale communication system, to overcome shortcomings that former electrical communication has, the introduction of optical communication system is actively being carried out and especially for transmission of power information such as protection, monitoring and control of electric power system operation, optical fiber composite overhead ground wire(OPGW) is increasingly built in the field. Accordingly, from formerly installed optical fibers in OPGW, by utilizing fiber`s low loss, wide bandwidth, high dielectric properties, system information for maintenance, i.e. fault information, weather information, etc. are directly sent to the maintenance department. This promotion in modernization of power transmission line maintenance will set up basis for the realization of effective management, automatic control and remote sensing in maintenance tasks. Eventually, this system can provides various information such as wind velocity and direction, state of aircraft warning lamp and fault current information ground wire etc.. (author). 38 refs., figs.

  19. Demonstration of Cascaded In-Line Single-Pump Fiber Optical Parametric Amplifiers in Recirculating Loop Transmission

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Ozolins, Oskars; An, Yi

    2012-01-01

    The performance of cascaded single-pump fiber optical parametric amplifiers (FOPAs) is experimentally studied for the first time using recirculating loop transmission with 80-km dispersion managed spans. Error-free performance has been achieved over 320 km for 40-Gbit/s CSRZ-OOK and CSRZ...

  20. Experimental Investigation of Transmission Properties and All-Optical Label Swapping of Orthogonal IM/FSK Labeled Signals

    Institute of Scientific and Technical Information of China (English)

    Pablo V. Holm-Nielsen; Nan Chi; Jianfeng Zhang; Christophe Peucheret; Idelfonso Tafur Monroy; Palle Jeppesen

    2003-01-01

    Optically labeled IM/FSK signal saretran smitte dover 50km of SMF under different compensation schemes.All-opticallabel swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall power penalty.

  1. A Novel Noise Free Transmission Technique for Designing 100Gb/s Future Generation Optical Communication System

    DEFF Research Database (Denmark)

    Das, Bhagwan; Abdullah, M.F.L.; Pandey, Bishwajeet

    2017-01-01

    Differential Phase Shift Keying (DPSK) techniques are widely used in designing the high-speed communication systems. However, these techniques still need improvement for long haul communication system design. In this paper, high-speed optical signal transmission and reception system is achieved f...

  2. Ab initio analytical model of light transmission through a cylindrical subwavelength hole in an optically thick film

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    2011-01-01

    The rigorous analytical theory of light transmission through a cylindrical hole of arbitrary diameter in an optically thick film is developed. The approach is based on the introduction of fictitious surface currents at both hole openings and both film surfaces. The solution of Maxwell’s equations...

  3. Experimental Investigation of transmission properties of all-optical label swapping of orthogonal IM/FSK labeled signals

    DEFF Research Database (Denmark)

    Holm-Nielsen, Pablo Villanueva; Chi, Nan; Zhang, Jianfeng;

    2003-01-01

    Optically labeled IM/FSK signal saretran smitte dover 50km of SMF under different compensation schemes.All-opticallabel swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall power penalty....

  4. Design and implementation of the optical fiber control and transmission module in multi-channel broadband digital receiver

    Science.gov (United States)

    Zhao, Ying-xiao; Zhang, Yue; Fan, Li-jie; Li, Wei-xing; Chen, Zeng-ping

    2014-09-01

    An optical fiber control and transmission module is designed and realized based on Virtex-7 field programmable gata array (FPGA), which can be applied in multi-channel broadband digital receivers. The module consists of sampling data transfer submodule and multi-channel synchronous sampling control submodule. The sampling data transmission in 4× fiber link channel is realized with the self-defined transfer protocol. The measured maximum data rate is 4.97 Gbyte/s. By connecting coherent clocks to the transmitter and receiver endpoints and using the self-defined transfer protocol, multi-channel sampling control signals transferred in optical fibers can be received synchronously by each analog-to-digital converter (ADC) with high accuracy and strong anti-interference ability. The module designed in this paper has certain reference value in increasing the transmission bandwidth and the synchronous sampling accuracy of multi-channel broadband digital receivers.

  5. Intrachannel cross-phase modulation-induced phase shift in high-speed dispersion-managed optical fiber transmission system

    Science.gov (United States)

    Syed, Nitu; Faisal, Mohammad

    2013-12-01

    We investigate the intrachannel cross-phase modulation (IXPM)-induced phase shift in optical return-to-zero pulse propagating in a periodically dispersion-managed long-haul optical fiber transmission line. Necessary dynamical equations for various pulse parameters have been derived using variational analysis to estimate the phase shift. These equations are solved by the Runge-Kutta method. The analytical result is verified by numerical simulation based on split-step Fourier method. We therefore explore the effects of various parameters, such as transmission distance, input power, duty cycle, dispersion map strength, and residual dispersion, on phase shift for a 40 Gb/s single-channel transmission system. We also check the impact of variation of bit rate on phase shift. We find that IXPM-induced phase shift can be mitigated by proper adjustment of dispersion management and different pulse parameters like duty cycle, dispersion map strength, and peak power.

  6. Transmission of 10 GHz,3.5 ps Optical Pulses Over 100-km Standard Fiber Using Mid-span Spectral Inversion

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jianfeng; YAO Minyu; PENG Can; ZHANG Hongming; XU Qianfan; GAO Yizhi

    2002-01-01

    Transmission of 3.5ps optical pulses over 100-km standard fiber was demonstrated by employing phase conjugation in a semiconductor optical amplifier to compensate the chromatic dispersion.The pulses were broadened to 5 ps after transmission,which confirms the applicability of this technique to ultra high-bit-rate system beyond 40 Gb/s.

  7. Extraordinary optical transmission with tapered slits: effect of higher diffraction and slit resonance orders

    DEFF Research Database (Denmark)

    Sondergaard, T.; Bozhevolnyi, S. I.; Beermann, J.;

    2012-01-01

    Transmission through thin metal films with a periodic arrangement of tapered slits is considered. Transmission maps covering a wide range of periods, film thicknesses, and taper angles are presented. The maps show resonant transmission when fundamental and higher-order slit resonances are excited....... A study of the effect on transmission of different combinations of available transmission and reflection diffraction orders show optimum total transmission when only the fundamental reflection order and higher transmission diffraction orders are available. The optimum taper angle is shown...

  8. The GTC exoplanet transit spectroscopy survey . VII. An optical transmission spectrum of WASP-48b

    Science.gov (United States)

    Murgas, F.; Pallé, E.; Parviainen, H.; Chen, G.; Nortmann, L.; Nowak, G.; Cabrera-Lavers, A.; Iro, N.

    2017-09-01

    Context. Transiting planets offer an excellent opportunity for characterizing the atmospheres of extrasolar planets under very different conditions from those found in our solar system. Aims: We are currently carrying out a ground-based survey to obtain the transmission spectra of several extrasolar planets using the 10 m Gran Telescopio Canarias. In this paper we investigate the extrasolar planet WASP-48b, a hot Jupiter orbiting around an F-type star with a period of 2.14 days. Methods: We obtained long-slit optical spectroscopy of one transit of WASP-48b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph. We integrated the spectrum of WASP-48 and one reference star in several channels with different wavelength ranges, creating numerous color light curves of the transit. We fit analytic transit curves to the data taking into account the systematic effects present in the time series in an effort to measure the change of the planet-to-star radius ratio (Rp/Rs) across wavelength. The change in transit depth can be compared with atmosphere models to infer the presence of particular atomic or molecular compounds in the atmosphere of WASP-48b. Results: After removing the transit model and systematic trends to the curves we reached precisions between 261 ppm and 455-755 ppm for the white and spectroscopic light curves, respectively. We obtained Rp/Rs uncertainty values between 0.8 × 10-3 and 1.5 × 10-3 for all the curves analyzed in this work. The measured transit depth for the curves made by integrating the wavelength range between 530 nm and 905 nm is in agreement with previous studies. We report a relatively flat transmission spectrum for WASP-48b with no statistical significant detection of atmospheric species, although the theoretical models that fit the data more closely include TiO and VO. The transit light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http

  9. Transmissive grating-reflective mirror-based fiber optic accelerometer for stable signal acquisition in industrial applications

    Science.gov (United States)

    Lee, Yeon-Gwan; Kim, Dae-Hyun; Kim, Chun-Gon

    2012-05-01

    This paper discusses an applicable fiber-optic accelerometer composed of a transmissive grating panel, a reflection mirror, and two optical fibers with a separation of quarter grating pitch as transceivers that monitor the low-frequency accelerations of civil engineering structures. This sensor structure brings together the advantages of both a simple sensor structure, which leads to simplified cable design by 50% in comparison with the conventional transmission-type fiber optic accelerometer, and a stable reflected signals acquisition with repeatability in comparison to the researched grating-reflection type fiber optic accelerometer. The vibrating displacement and sinusoidal acceleration measured from the proposed fiber optic sensor demonstrated good agreement with those of a commercial laser displacement sensor and a MEMS accelerometer without electromagnetic interference. The developed fiber optic accelerometer can be used in frequency ranges below 4.0 Hz with a margin of error that is less than 5% and a high sensitivity of 5.06 rad/(m/s)2.

  10. Optical-bistability-enabled control of resonant light transmission for an atom-cavity system

    Science.gov (United States)

    Sawant, Rahul; Rangwala, S. A.

    2016-02-01

    The control of light transmission through a standing-wave Fabry-Pérot cavity containing atoms is theoretically and numerically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained. The response of the intracavity intensity to an intersecting beam on atomic resonance is understood in the presence of stationary atoms (closed system) and nonstatic atoms (open system) in the cavity. The nonstatic system of atoms is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, which corresponds to a thermal environment where atoms are moving in and out of the cavity mode volume. The control behavior with three- and two-level atomic systems is also studied, and the rich physics arising out of these systems for closed and open atomic systems is discussed. The solutions to the models are used to interpret the steady-state and transient behavior observed by Sharma et al. [Phys. Rev. A 91, 043824 (2015)], 10.1103/PhysRevA.91.043824.

  11. Optical bistability enabled control of resonant light transmission for an atom-cavity system

    CERN Document Server

    Sawant, Rahul

    2015-01-01

    The control of light transmission through a Fabry-Perot cavity containing atoms is theoretically investigated, when the cavity mode beam and an intersecting control beam are both close to specific atomic resonances. A four-level atomic system is considered and its interaction with the cavity mode is studied by solving for the time dependent cavity field and atomic state populations. The conditions for optical bistability of the atom-cavity system are obtained in steady state limit. For an ensemble of atoms in the cavity mode, the response of the intra-cavity light intensity to the intersecting resonant beam is understood for stationary atoms (closed system) and non-static atoms (open system). The open system is modelled by adjusting the atomic state populations to represent the exchange of atoms in the cavity mode, with the thermal environment. The solutions to the model are used to qualitatively explain the observed steady state and transient behaviour of the light in the cavity mode, in Sharma et. al. [1]. ...

  12. Descriptive parameters of the erythrocyte aggregation phenomenon using a laser transmission optical chip

    Science.gov (United States)

    Toderi, Martín A.; Castellini, Horacio V.; Riquelme, Bibiana D.

    2017-01-01

    The study of red blood cell (RBC) aggregation is of great interest because of its implications for human health. Altered RBC aggregation can lead to microcirculatory problems as in vascular pathologies, such as hypertension and diabetes, due to a decrease in the erythrocyte surface electric charge and an increase in the ligands present in plasma. The process of erythrocyte aggregation was studied in stasis situation (free shear stresses), using an optical chip based on the laser transmission technique. Kinetic curves of erythrocyte aggregation under different conditions were obtained, allowing evaluation and characterization of this process. Two main characteristics of blood that influence erythrocyte aggregation were analyzed: the erythrocyte surface anionic charge (EAC) after digestion with the enzyme trypsin and plasmatic protein concentration in suspension medium using plasma dissolutions in physiological saline with human albumin. A theoretical approach was evaluated to obtain aggregation and disaggregation ratios by syllectograms data fitting. Sensible parameters (Amp100, t) regarding a reduced erythrocyte EAC were determined, and other parameters (AI, M-Index) resulted that are representative of a variation in the plasmatic protein content of the suspension medium. These results are very useful for further applications in biomedicine.

  13. Unformatted Digital Fiber-Optic Data Transmission for Radio Astronomy Front-Ends

    CERN Document Server

    Morgan, Matthew A; Castro, Jason J

    2013-01-01

    We report on the development of a prototype integrated receiver front-end that combines all conversions from RF to baseband, from analog to digital, and from copper to fiber into one compact assembly, with the necessary gain and stability suitable for radio astronomy applications. The emphasis in this article is on a novel digital data link over optical fiber which requires no formatting in the front-end, greatly reducing the complexity, bulk, and power consumption of digital electronics inside the antenna, facilitating its integration with the analog components, and minimizing the self-generated radio-frequency interference (RFI) which could leak into the signal path. Management of the serial data link is performed entirely in the back-end based on the statistical properties of signals with a strong random noise component. In this way, the full benefits of precision and stability afforded by conventional digital data transmission are realized with far less overhead at the focal plane of a radio telescope.

  14. Improved FEC Code Based on Concatenated Code for Optical Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-guo; JIANG Ze; MAO You-ju

    2006-01-01

    The improved three novel schemes of the super forward error correction(super-FEC) concatenated codes are proposed after the development trend of long-haul optical transmission systems and the defects of the existing FEC codes have been analyzed. The performance simulation of the Reed-Solomon(RS)+Bose-Chaudhuri-Hocguenghem(BCH) inner-outer serial concatenated code is implemented and the conceptions of encoding/decoding the parallel-concatenated code are presented. Furthermore,the simulation results for the RS(255,239)+RS(255,239) code and the RS(255,239)+RS(255,223) code show that the two consecutive concatenated codes are a superior coding scheme with such advantages as the better error correction,moderate redundancy and easy realization compared to the classic RS(255,239) code and other codes,and their signal to noise ratio gains are respectively 2~3 dB more than that of the RS(255,239)code at the bit error rate of 1×10-13. Finally,the frame structure of the novel consecutive concatenated code is arranged to lay a firm foundation in designing its hardware.

  15. A linear laser-driver array for optical transmission in the LHC experiments

    CERN Document Server

    Cervelli, G; Moreira, P; Vasey, F

    2000-01-01

    A 4-way linear laser driver has been designed and implemented in a commercial 0.25 mu m CMOS technology. The full-custom IC is intended for analogue and digital data transmission as part of the 50 000 optical fibre links of the CMS particle tracking system. Intrinsic radiation tolerance and specific design methodologies enable the device to operate over 10 years in the harsh radiation environment of the innermost LHC detectors. Although optimised for analogue operation the driver is compatible with LVDS digital signalling. A combination of linearization methods achieves good analogue performance (8-bit equivalent dynamic range with a bandwidth of 100 MHz), while maintaining wide input common-mode range (+or-350 mV) and limited power dissipation. The linearly amplified signal is added to a DC current, which can be set over a wide range (-60 mA to +60 mA). The latter capability allows tracking of changes in laser threshold due to ageing or radiation damage. The driver gain and bias current are set via a serial ...

  16. Descriptive parameters of the erythrocyte aggregation phenomenon using a laser transmission optical chip.

    Science.gov (United States)

    Toderi, Martín A; Castellini, Horacio V; Riquelme, Bibiana D

    2017-01-01

    The study of red blood cell (RBC) aggregation is of great interest because of its implications for human health. Altered RBC aggregation can lead to microcirculatory problems as in vascular pathologies, such as hypertension and diabetes, due to a decrease in the erythrocyte surface electric charge and an increase in the ligands present in plasma. The process of erythrocyte aggregation was studied in stasis situation (free shear stresses), using an optical chip based on the laser transmission technique. Kinetic curves of erythrocyte aggregation under different conditions were obtained, allowing evaluation and characterization of this process. Two main characteristics of blood that influence erythrocyte aggregation were analyzed: the erythrocyte surface anionic charge (EAC) after digestion with the enzyme trypsin and plasmatic protein concentration in suspension medium using plasma dissolutions in physiological saline with human albumin. A theoretical approach was evaluated to obtain aggregation and disaggregation ratios by syllectograms data fitting. Sensible parameters ( Amp 100 , t 1 \\ 2 ) regarding a reduced erythrocyte EAC were determined, and other parameters (AI, M-Index) resulted that are representative of a variation in the plasmatic protein content of the suspension medium. These results are very useful for further applications in biomedicine.

  17. Numerical analysis on using compound parabolic couplers for direct transmission of concentrated solar radiation via optical fibre (Conference Presentation)

    Science.gov (United States)

    Rahou, Maryam; Andrews, John; Rosengarten, Gary

    2016-09-01

    A challenge in high-temperature solar thermal applications is transfer of concentrated solar radiation to the load with minimum energy loss. The use of a solar concentrator in conjunction with optical fibres has potential advantages in terms of transmission efficiency, technical feasibility and cost-effectiveness compared to a conventional heat transfer system employing heat exchangers and a heat transfer fluid. For transferring higher levels of concentrated flux it is necessary to employ multiple optical fibres or fibre bundles. However, the losses at the incident plane of a bundle due to absorption by the epoxy and cladding between the individual fibres in a bundle are substantial, typically over 60% of the overall transmission loss. The optical transmission of the system can thus be enhanced by employing a coupler between the concentrated solar radiation and the entrance to the bundle that reflects all incident light into the cores of individual fibres rather than allowing it to strike the interstitial spaces between the cores. This paper describes the design for such couplers based on multiple compound parabolic (CP) reflectors each with its exit aperture coinciding with the core of an individual fibre within the bundle. The proposed design employs external reflection from a machined metallic aluminium surface. This CP arrangement has the additional benefit of increasing the concentration ratio of the primary solar concentrator used. Simulation modeling using LightTools is conducted into a parabolic Cassegrain solar concentrator employing these CP couplers prior to a fibre bundle. The dependence of overall transmission and total optical efficiency of the system over lengths of the bundle up to 100 m are investigated quantitatively. In addition, the influence on transmission of the angular distribution of radiation intensity at the aperture of the couplers is studied.

  18. Asymmetric transmission and optical low-pass filtering in a stack of random media with graded transport mean free path

    Science.gov (United States)

    Bingi, J.; Hemalatha, M.; Anita, R. W.; Vijayan, C.; Murukeshan, V. M.

    2015-11-01

    Light transport and the physical phenomena related to light propagation in random media are very intriguing, they also provide scope for new paradigms of device functionality, most of which remain unexplored. Here we demonstrate, experimentally and by simulation, a novel kind of asymmetric light transmission (diffusion) in a stack of random media (SRM) with graded transport mean free path. The structure is studied in terms of transmission, of photons propagated through and photons generated within the SRM. It is observed that the SRM exhibits asymmetric transmission property with a transmission contrast of 0.25. In addition, it is shown that the SRM works as a perfect optical low-pass filter with a well-defined cutoff wavelength at 580 nm. Further, the photons generated within the SRM found to exhibit functionality similar to an optical diode with a transmission contrast of 0.62. The basis of this functionality is explained in terms of wavelength dependent photon randomization and the graded transport mean free path of SRM.

  19. Low complexity MIMO method based on matrix transformation for few-mode multi-core optical transmission system

    Science.gov (United States)

    Pan, Xiaolong; Liu, Bo; Li, Li; Tian, Qinghua

    2016-07-01

    This paper proposes and demonstrates a low complexity multiple-input multiple-output (MIMO) equalization digital signal processing (DSP) method for the few mode multi-core (FMMC) fiber optical transmission system. The MIMO equalization algorithm offers adaptive equalization taps according to the degree of crosstalk in cores or modes, which eliminates the interference among different modes and cores in space division multiplexing (SDM) transmission system. Compared with traditional MIMO method, the proposed scheme has increased the convergence rate by 4 times and reduced the number of finite impulse response (FIR) filters by 55% when the numbers of mode and core are three.

  20. Near-infrared transmission spectroscopy of aqueous solutions: The influence of optical pathlength on signal-to-noise ratio

    DEFF Research Database (Denmark)

    Jensen, P.S.; Bak, J.

    2002-01-01

    The optimal choice of optical pathlength, source intensity, and detector for near-infrared transmission measurements of trace components in aqueous solutions depends on the strong absorption of water. In this study we examine under which experimental circumstances one may increase the pathlength...... to obtain a measurement with higher signal-to-noise ratio. The noise level of measurements at eight different pathlengths from 0.2 to 2.0 mm of pure water and of 1 g/dL aqueous glucose signals were measured using a Fourier transform near-infrared spectrometer and a variable pathlength transmission cell...

  1. Design of transmission line driven slot waveguide Mach-Zehnder interferometers and application to analog optical links.

    Science.gov (United States)

    Witzens, Jeremy; Baehr-Jones, Thomas; Hochberg, Michael

    2010-08-02

    Slot waveguides allow joint confinement of the driving electrical radio frequency field and of the optical waveguide mode in a narrow slot, allowing for highly efficient polymer based interferometers. We show that the optical confinement can be simply explained by a perturbation theoretical approach taking into account the continuity of the electric displacement field. We design phase matched transmission lines and show that their impedance and RF losses can be modeled by an equivalent circuit and linked to slot waveguide properties by a simple set of equations, thus allowing optimization of the device without iterative simulations. We optimize the interferometers for analog optical links and predict record performance metrics (V(pi) = 200 mV @ 10 GHz in push-pull configuration) assuming a modest second order nonlinear coefficient (r(33) = 50 pm/V) and slot width (100 nm). Using high performance optical polymers (r(33) = 150 pm/V), noise figures of state of the art analog optical links can be matched while reducing optical power levels by approximately 30 times. With required optical laser power levels predicted at 50 mW, this could be a game changing improvement by bringing high performance optical analog link power requirements in the reach of laser diodes. A modified transmitter architecture allows shot noise limited performance, while reducing power levels in the slot waveguides and enhancing reliability.

  2. Enhancement of magneto-optical Faraday effects and extraordinary optical transmission in a tri-layer structure with rectangular annular arrays.

    Science.gov (United States)

    Lei, Chengxin; Chen, Leyi; Tang, Zhixiong; Li, Daoyong; Cheng, Zhenzhi; Tang, Shaolong; Du, Youwei

    2016-02-15

    The properties of optics and magneto-optical Faraday effects in a metal-dielectric tri-layer structure with subwavelength rectangular annular arrays are investigated. It is noteworthy that we obtained the strongly enhanced Faraday rotation of the desired sign along with high transmittance by optimizing the parameters of the nanostructure in the visible spectral ranges. In this system, we obtained two extraordinary optical transmission (EOT) resonant peaks with enhanced Faraday rotations, whose signs are opposite, which may provide the possibility of designing multi-channel magneto-optical devices. Study results show that the maximum of the figure of merit (FOM) of the structure can be obtained between two EOT resonant peaks accompanied by an enhanced Faraday rotation. The positions of the maximum value of the FOM and resonant peaks of transmission along with a large Faraday rotation can be tailored by simply adjusting the geometric parameters of our models. These research findings are of great importance for future applications of magneto-optical devices.

  3. Nanoimprint-defined, large-area meta-surfaces for unidirectional optical transmission with superior extinction in the visible-to-infrared range.

    Science.gov (United States)

    Yao, Yuhan; Liu, He; Wang, Yifei; Li, Yuanrui; Song, Boxiang; Wang, Richard P; Povinelli, Michelle L; Wu, Wei

    2016-07-11

    Optical devices with asymmetric transmission have important applications in optical systems, but optical isolators with the modal asymmetry can only be built using magneto-optical or nonlinear materials, as dictated by the Lorentz reciprocity theorem. However, optical devices with the power asymmetry can be achieved by linear materials such as metals and dielectrics. In this paper, we report a large-area, nanoimprint-defined meta-surface (stacked subwavelength gratings) with high-contrast asymmetric transmittance in the visible-to-infrared wavelength range for TM-polarized light. The physical origin of asymmetric transmission through the meta-surface is studied by analyzing the scattering matrix.

  4. Management of light absorption in extraordinary optical transmission based ultra-thin-film tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mashooq, Kishwar; Talukder, Muhammad Anisuzzaman, E-mail: anis@eee.buet.ac.bd [Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1205 (Bangladesh)

    2016-05-21

    Although ultra-thin-film solar cells can be attractive in reducing the cost, they suffer from low absorption as the thickness of the active layer is usually much smaller than the wavelength of incident light. Different nano-photonic techniques, including plasmonic structures, are being explored to increase the light absorption in ultra-thin-film solar cells. More than one layer of active materials with different energy bandgaps can be used in tandem to increase the light absorption as well. However, due to different amount of light absorption in different active layers, photo-generated currents in different active layers will not be the same. The current mismatch between the tandem layers makes them ineffective in increasing the efficiency. In this work, we investigate the light absorption properties of tandem solar cells with two ultra-thin active layers working as two subcells and a metal layer with periodically perforated holes in-between the two subcells. While the metal layer helps to overcome the current mismatch, the periodic holes increase the absorption of incident light by helping extraordinary optical transmission of the incident light from the top to the bottom subcell, and by coupling the incident light to plasmonic and photonic modes within ultra-thin active layers. We extensively study the effects of the geometry of holes in the intermediate metal layer on the light absorption properties of tandem solar cells with ultra-thin active layers. We also study how different metals in the intermediate layer affect the light absorption; how the geometry of holes in the intermediate layer affects the absorption when the active layer materials are changed; and how the intermediate metal layer affects the collection of photo-generated electron-hole pairs at the terminals. We find that in a solar cell with 6,6-phenyl C61-butyric acid methyl ester top subcell and copper indium gallium selenide bottom subcell, if the periodic holes in the metal layer are square or

  5. Management of light absorption in extraordinary optical transmission based ultra-thin-film tandem solar cells

    Science.gov (United States)

    Mashooq, Kishwar; Talukder, Muhammad Anisuzzaman

    2016-05-01

    Although ultra-thin-film solar cells can be attractive in reducing the cost, they suffer from low absorption as the thickness of the active layer is usually much smaller than the wavelength of incident light. Different nano-photonic techniques, including plasmonic structures, are being explored to increase the light absorption in ultra-thin-film solar cells. More than one layer of active materials with different energy bandgaps can be used in tandem to increase the light absorption as well. However, due to different amount of light absorption in different active layers, photo-generated currents in different active layers will not be the same. The current mismatch between the tandem layers makes them ineffective in increasing the efficiency. In this work, we investigate the light absorption properties of tandem solar cells with two ultra-thin active layers working as two subcells and a metal layer with periodically perforated holes in-between the two subcells. While the metal layer helps to overcome the current mismatch, the periodic holes increase the absorption of incident light by helping extraordinary optical transmission of the incident light from the top to the bottom subcell, and by coupling the incident light to plasmonic and photonic modes within ultra-thin active layers. We extensively study the effects of the geometry of holes in the intermediate metal layer on the light absorption properties of tandem solar cells with ultra-thin active layers. We also study how different metals in the intermediate layer affect the light absorption; how the geometry of holes in the intermediate layer affects the absorption when the active layer materials are changed; and how the intermediate metal layer affects the collection of photo-generated electron-hole pairs at the terminals. We find that in a solar cell with 6,6-phenyl C61-butyric acid methyl ester top subcell and copper indium gallium selenide bottom subcell, if the periodic holes in the metal layer are square or

  6. Issues arising with the application of optical fiber transmission in class 1E systems in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Korsah, K. [Oak Ridge National Lab., TN (United States); Antonescu, C. [Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research

    1993-12-31

    The application of fiber optic links and networks in safety-critical systems in the next generation of nuclear power plants, as well as in some digital upgrades in present-day plants, will mean that these links must be highly reliable and able to withstand the effect of environmental stressors present at the installation location. This paper discusses the failure modes and age-related mechanisms of fiber optic transmission components and identifies environmental stressors that could adversely affect their reliability over the long term. Some of the standards that could be used in their qualification for safety-critical applications are also discussed briefly.

  7. Simultaneous transmission of the IEEE 802.11 radio signal and optical Gbit Ethernet over the multimode fiber link

    Science.gov (United States)

    Maksymiuk, L.; Podziewski, A.

    2015-09-01

    In the paper we present a successful joint transmission of the IEEE 802.11 signal and an optical Gbit Ethernet over a multimode fiber based link. Most importantly, the multiplexation of both signals was performed in the optical domain. Due to the utilization of the multimode fiber the OBI noise was avoided and both channels were able to operate at the same wavelength. We prove that potential RoF link for IEEE 802.11 signal distribution may be used to additionally transmit other signals as Gbit Ethernet and therefore utilize the fiber infrastructure installed more effectively. The qualities of both the IEEE 802.11 and Ethernet transmissions fulfilled the requirements imposed by appropriate standards.

  8. Clock-distribution with instantaneous synchronization for 160 Gbit/s optical time-domain multiplexed systems packet transmission.

    Science.gov (United States)

    Gomez-Agis, Fausto; Calabretta, Nicola; Albores-Mejia, Aaron; Dorren, Harm J S

    2010-10-01

    We demonstrate for the first time, to our knowledge, a clock-distribution method for ultra-high-speed optical time-domain multiplexed systems data packets that provides instantaneous synchronization, fast locking/unlocking times, and a highly stable bursty clock, enabling error-free operation of 160 to 10 Gbit/s time demultiplexing with a power penalty of 1.5 dB after 51 km transmission in standard single-mode fiber (ITU G.652).

  9. Stimulated recovery of the optical transmission of PbWO 4 scintillation crystals for electromagnetic calorimeters after radiation damage

    Science.gov (United States)

    Dormenev, V.; Kuske, T.; Novotny, R. W.; Borisevich, A.; Fedorov, A.; Korjik, M.; Mechinski, V.; Missevitch, O.; Lugert, S.

    2010-11-01

    In this paper we describe the phenomenon of the stimulated recovery of radiation damage in lead tungstate scintillation crystals achieved via illumination by visible and infrared light. It allows fast and efficient in-situ recovery of the optical transmission either during beam-off periods or on-line during data accumulation. The application can substantially improve or extend the running period of the experiment by keeping the damage at a tolerable level.

  10. New fault location system for power transmission lines using composite fiber-optic overhead ground wire (OPGW)

    Energy Technology Data Exchange (ETDEWEB)

    Urasawa, K. (Tokyo Electric Power Co., Inc. (Japan)); Kanemaru, K.; Toyota, S.; Sugiyama, K. (Hitachi Cable, Ltd., Tokyo (Japan))

    1989-10-01

    A new fault location (FL) method using composite fiber-optic overhead ground wires (OPGWs) is developed to find out where electrical faults occur on overhead power transmission lines. This method locates the fault section by detecting the current induced in the ground wire (GW), i.e. OPGW in this system. Since detected fault information is essentially uncertain, the new FL method treats the fault information oas a current distribution pattern throughout the power line, and applies Fuzzy Theory to realize the human-like manner of fault location used by electrical power engineers. It was confirmed by computer simulations that the fault section can be accurately located using this method under various conditions. This FL system has already been applied to several commercial power transmission lines and successfully located the sections where electrical faults occurred on actual power transmission lines.

  11. Resonance amplification of left-handed transmission at optical frequencies by stimulated emission of radiation in active metamaterials.

    Science.gov (United States)

    Dong, Zheng-Gao; Liu, Hui; Li, Tao; Zhu, Zhi-Hong; Wang, Shu-Ming; Cao, Jing-Xiao; Zhu, Shi-Ning; Zhang, X

    2008-12-01

    We demonstrate that left-handed resonance transmission from metallic metamaterial, composed of periodically arranged double rings, can be extended to visible spectrum by introducing an active medium layer as the substrate. The severe ohmic loss inside metals at optical frequencies is compensated by stimulated emission of radiation in this active system. Due to the resonance amplification mechanism of recently proposed lasing spaser, the left-handed transmission band can be restored up to 610 nm wavelength, in dependence on the gain coefficient of the active layer. Additionally, threshold gains for different scaling levels of the double-ring unit are investigated to evaluate the gain requirement of left-handed transmission restoration at different frequency ranges.

  12. Ultra-precise measurement of optical aberrations for sub-Aangstroem transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barthel, J.

    2008-06-15

    Quantitative investigations of material structures on an atomic scale by means of highresolution transmission electron microscopy (HRTEM) impose not only extreme demands on the mechanic and electromagnetic stability of the applied instruments but require also their precise electron-optical adjustment. Today a physical resolution well below one Aangstroem can be achieved with commercially available microscopes on a daily basis. However, the achieved resolution can often not be reliably exploited for the interpretation of the resulting microscopical data due to the presence of so-called higher-order lens aberrations. At the starting time of this work, a sufficiently accurate procedure to measure higher-order aberrations was urgently missing. Since aberration measurement is a mandatory prerequisite for any technique of aberration control enabling quantitative high-resolution microscopy, the goal of this work is to develop such a measurement procedure for the Sub-Aangstroem regime. The measurement procedures developed in the course of this work are based on the numerical evaluation of a series of images taken from an amorphous object under electron-beam illumination with varying tilt. New techniques have been developed for the evaluation of single images as well as for the optimised evaluation of the whole series. These procedures allow microscope users to perform quantitative HRTEM even at a resolution of 0.5 Aangstroem. The precision reached with the newly developed measurement procedures is unprecedented and surpasses existing solutions by at least one order of magnitude in any respect. All the concepts and procedures for aberration measurement developed in this work have been implemented in a software package which satisfies professional demands with respect to robustness, precision, speed and user-friendliness. The new automatic aberrationmeasurement procedures are suitable to establish HRTEM as a quantitative technique for material science investigations in the

  13. A novel approach to smart grid technology for electrical power transmission lines by a self-organized optical network node based on optical bistability

    Science.gov (United States)

    Nakanishi, Soichiro; Sasaki, Wakao

    2011-01-01

    In this work, we have demonstrated a new smart grid model by our novel green photonics technology based on selforganized optical networks realizing an autonomous peer-to-peer electric power transmissions without centralized control for the power grid. In this optical network, we introduced an adaptive algorithm for concurrent peer-to-peer communications, by utilizing optical nonlinearity depending only on the signal strength passing through the network. This method is applicable for autonomous organization of functions for ad-hoc electric power distribution systems for the power grid. For this purpose, a simple optical- electrical hybrid bistable circuit composed of such as light emitting diode (LED) and photo diode (PD), has been incorporated into the network node. In the experiment, the method uses a simple, local adaptation of transmission weights at each network node, which enables self-organizing functions of the network, such as self-routing, self-optimization, self-recovery and self-protection. Based on this method, we have demonstrated experimentally a new smart grid model applicable for ad-hoc electric power distribution systems mediated by power comsumptions. In this model, electric power flow is controlled autonomously through the self-organized network nodes associated with individual power facilities having photovoltaics and electric storage devices, etc., and the nodes convert the amounts of electric power supply and/or comsumption to the light intensity values using above mentioned transmission weights at each node. As a consequence, we have experimentally demonstrated a simple shorthaul system model for ad-hoc electric power distribution with a self-organized optical network as a novel green photonics technology application for smart grid.

  14. A Novel Noise Free Transmission Technique for Designing 100Gb/s Future Generation Optical Communication System

    DEFF Research Database (Denmark)

    Das, Bhagwan; Abdullah, M.F.L.; Pandey, Bishwajeet

    2017-01-01

    Differential Phase Shift Keying (DPSK) techniques are widely used in designing the high-speed communication systems. However, these techniques still need improvement for long haul communication system design. In this paper, high-speed optical signal transmission and reception system is achieved f...... the transmission and reception of data for high-speed long haul communication system without using any amplifier or repeater.......Differential Phase Shift Keying (DPSK) techniques are widely used in designing the high-speed communication systems. However, these techniques still need improvement for long haul communication system design. In this paper, high-speed optical signal transmission and reception system is achieved...... that BER of 10-12+, Q-factor 98 at power penalty of 14 dB is attained using the designed technique for transmitting 100Gb/s at 300 Km. Whereas, existing NRZ technique achieved a BER of 10-6, Q-factor 32 at power penalty of 11 dB for same similar transmission data rate and distance. The designed offers...

  15. One-way optical transmission in silicon photonic crystal heterojunction with circular and square scatterers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dan, E-mail: liudanhu725@126.com [School of Physics and Mechanical & Electrical Engineering, Hubei University of Education, Wuhan, 430205 (China); Hu, Sen [School of Physics and Mechanical & Electrical Engineering, Hubei University of Education, Wuhan, 430205 (China); Gao, Yihua [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, Huazhong University of Science and Technology (HUST), Wuhan, 430074 (China)

    2017-07-12

    A 2D orthogonal square-lattice photonic crystal (PC) heterojunction consisting of circular and square air holes in silicon is presented. Band structures are calculated using the plane wave expansion method, and the transmission properties are investigated by the finite-different time-domain simulations. Thanks to the higher diffraction orders excited when the circular and square holes are interlaced along the interface, one-way transmission phenomena can exist within wide frequency regions. The higher order diffraction is further enhanced through two different interface optimization designs proposed by modifying the PC structure of the hetero-interface. An orthogonal PC heterojunction for wide-band and efficient one-way transmission is constructed, and the maximum transmissivity is up to 78%. - Highlights: • Photonic crystal heterojunction with circular and square scatterers is first studied. • One-way transmission efficiency is closely related to the hetero-interface. • Wide-band and efficient one-way transmission is realized.

  16. Simultaneous dispersion and non-linearity compensation with mid-span optical phase conjugation and distributed Raman amplifier for a sub-carrier multiplexed optical transmission link

    Science.gov (United States)

    Chandra, S.; Vardhanan, A. Vishnu; Gangopadhyay, R.

    2007-11-01

    Optical phase conjugation (OPC) and distributed Raman amplifier (DRA) combination (OPC-DRA) is demonstrated as a potential enabling solution for simultaneous reduction of fiber non-linearities and dispersion compensation of a sub-carrier multiplexed (SCM) optical transmission link. The present work is focused on the use of OPC-DRA combination for system performance improvement in terms of composite second order distortion (CSO) and carrier to noise ratio (CNR) of the SCM link. The analysis further shows that, introduction of DRA with proper pumping scheme significantly reduce fiber non-linearity resulting in improvement of the system performance in terms of CNR, compared to the situation where only mid-way optical phase conjugation is used.

  17. Turbo Equalization Techniques Toward Robust PDM 16-QAM Optical Fiber Transmission

    DEFF Research Database (Denmark)

    Arlunno, Valeria; Caballero Jambrina, Antonio; Borkowski, Robert

    2014-01-01

    In this paper, we show numerically and experimentally that turbo equalization (TE) is an efficient technique to mitigate performance degradations stemming from optical fiber propagation effects in both optical fiber dispersion managed and unmanaged coherent detection links. The effectiveness...

  18. Monolithically integrated quantum dot optical gain modulator with semiconductor optical amplifier for 10-Gb/s photonic transmission

    Science.gov (United States)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

    2015-03-01

    Short-range interconnection and/or data center networks require high capacity and a large number of channels in order to support numerous connections. Solutions employed to meet these requirements involve the use of alternative wavebands to increase the usable optical frequency range. We recently proposed the use of the T- and O-bands (Thousand band: 1000-1260 nm, Original band: 1260-1360 nm) as alternative wavebands because large optical frequency resources (>60 THz) can be easily employed. In addition, a simple and compact Gb/s-order high-speed optical modulator is a critical photonic device for short-range communications. Therefore, to develop an optical modulator that acts as a highfunctional photonic device, we focused on the use of self-assembled quantum dots (QDs) as a three-dimensional (3D) confined structure because QD structures are highly suitable for realizing broadband optical gain media in the T+O bands. In this study, we use the high-quality broadband QD optical gain to develop a monolithically integrated QD optical gain modulator (QD-OGM) device that has a semiconductor optical amplifier (QD-SOA) for Gb/s-order highspeed optical data generation in the 1.3-μm waveband. The insertion loss of the device can be compensated through the SOA, and we obtained an optical gain change of up to ~7 dB in the OGM section. Further, we successfully demonstrate a 10-Gb/s clear eye opening using the QD-OGM/SOA device with a clock-data recovery sequence at the receiver end. These results suggest that the monolithic QD-EOM/SOA is suitable for increasing the number of wavelength channels for smart short-range communications.

  19. 10 Gb/s full-duplex bidirectional transmission with RSOA-based ONU using detuned optical filtering and decision feedback equalization.

    Science.gov (United States)

    Omella, M; Papagiannakis, I; Schrenk, B; Klonidis, D; Lázaro, J A; Birbas, A N; Kikidis, J; Prat, J; Tomkos, I

    2009-03-30

    Full-duplex bidirectional transmission at 10 Gb/s is demonstrated for extended wavelength division multiplexed passive optical network (WDM-PON) applications, achieving transmission distances up to 25 km of standard single mode fiber (SSMF) when using a low-bandwidth (approximately 1.2 GHz) reflective semiconductor optical amplifier (RSOA) for signal re-modulation at the optical network unit (ONU). The system is assisted by optimum offset filtering at the optical line terminal (OLT)-receiver and the performance is further improved with the use of decision-feedback equalization (DFE). Chromatic dispersion (CD) and Rayleigh Backscattering (RB) effects are considered and analyzed.

  20. Counteracting 16-QAM Optical Fiber Transmission Impairments With Iterative Turbo Equalization

    DEFF Research Database (Denmark)

    Arlunno, Valeria; Caballero Jambrina, Antonio; Borkowski, Robert;

    2013-01-01

    -division-multiplexing 16 quadrature amplitude modulation impairments in dispersion uncompensated coherent transmission links. Gains exceeding one order of magnitude in terms of bit error rate are obtained in experimental validation up to 497 km-standard single mode fiber link transmission....

  1. Theoretical Analysis of Measurement in Operation Efficiency in Optical Cable Transmission Networks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is necessary to study dynamic operation efficiency of transmission networks in order to realize high intensification of communication networks. The operation efficiency discussed here should exist not only in logic-circuit layer, but also in both path layer and medium layer. A theoretical method of the measurement of layers and comprehensive evaluations is presented based on the concept of transmission efficiency.

  2. Optical Transmission of OFDM Ultra-wideband Signals beyond 40 Gb/s (Invited Paper

    Directory of Open Access Journals (Sweden)

    Y. Ben-Ezra

    2010-02-01

    Full Text Available We for the first time propose the highly efficient method of RF and optical signal mixing based on two different architectures: the parallel-RF/serial-optics architecture characterized by all-optical mixing for sub-carrier multiplexing, and the parallel-RF/parallel-optics architecture based on the array of 12x10 GHz components with directly modulated VCSELs and 12 multimode optical fibers. The main advantages of the both architectures are simplicity and low-cost implementation. We have carried out numerical simulations of ultra-wideband signals propagation in the proposed systems and proved the high efficiency and feasibility of the proposed method.

  3. Optical phase conjugation for nonlinearity compensation in WDM PDM 16-QAM transmission over dispersion-compensated and dispersion-uncompensated links

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Sackey, I.; Jazayerifar, M.

    2015-01-01

    Kerr nonlinearity compensation by optical phase conjugation is demonstrated in a WDM PDM 16-QAM system. Improved received signal quality is reported for both dispersion-compensated and dispersion-uncompensated transmission and a comparison with digital backpropagation is provided....

  4. Simultaneous transmission of 256-QAM WIMAX at 5.7GHz and optically generated impulse radio UWB over fiber for indoor wireless multi-services

    DEFF Research Database (Denmark)

    Yu, Xianbin; Yin, Xiaoli; Gibbon, Timothy Braidwood;

    2010-01-01

    Fiber transmission of simultaneous optically generated FCC compliant 625Mbps impulse radio UWB and 80Mbps 256-QAM IEEE 802.16 WIMAX signals is experimentally demonstrated by using a single directly modulated light source.......Fiber transmission of simultaneous optically generated FCC compliant 625Mbps impulse radio UWB and 80Mbps 256-QAM IEEE 802.16 WIMAX signals is experimentally demonstrated by using a single directly modulated light source....

  5. Study for installation of fiber optic cables on operating transmission lines; Estudo para instalacao de cabos opticos em LTs em operacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Arnaldo Cursino [Eletronet, Rio de Janeiro, RJ (Brazil); Pardauil, Nagib Bechara [ELETRONORTE, Belem, PA (Brazil)

    2002-10-01

    This article performs a comparison among the various alternatives for implantation of an optical system in existing transmission lines. The work takes into consideration the substitution of lightning conductors by OPGW cables, the installation of self-sustained cables, the using of spined optical cables, the installation of a new transmission line and a case study for the 500 kV section between the Tucurui and Presidente Dutra substations.

  6. The generalized transmission matrix for electron-wave-optics through biased heterostructures: Quantum device applications

    Science.gov (United States)

    Kan'an, A. M.; Puri, A.

    1994-01-01

    The transmission matrix approach is generalized to calculate the transmission probability of obliquely incident electrons through arbitrary shape potential profiles. Transmission probability is obtained as a function of the electron energy, the angle of incidence, and the applied voltage across the structure. Applications to electron waveguide and quantum resonant tunneling are outlined. Numerical results are presented for angle dependent resonant tunneling through biased multibarrier GaAs-AlxGa1-xAs heterostructures. As a consequence, various novel quantum devices, i.e., high speed switch, tunable electron wave filter, and electron wave beam splitter are proposed.

  7. Performance Analysis on 16-Channels Wavelength Division Multiplexing in Free Space Optical Transmission under Tropical Regions Environment

    Directory of Open Access Journals (Sweden)

    Ratna K.Z. Sahbudin

    2012-01-01

    Full Text Available Problem statement: Wavelength-Division-Multiplexing (WDM is a promising technique for meeting the growing demand for increased bandwidth and various types of services in the optical access network. For wide area or metropolitan networks, fibers are deployed to provide huge bandwidth. In access networks, the fiber-to-the-home will partially solve the last mile problem. However, some environmentally sensitive area such as housing areas, tower buildings and national parks are not allowed to deploy fibers. Therefore, Radio Frequency (RF is normally used to overcome this problem. The incompatibility of RF and optical channels is now widely believed to be the limiting factor in efforts to further increase transport capabilities. Free Space Optical (FSO communication is the technology that can address any connectivity needed in optical networks, such as core, edge, or access networks. Approach: In this project, the simulation software namely Optical System version 7 is used to simulate the design of WDM in FSO transmission. The total losses that have been considered in this design are geometric loss, transmitter and receiver loss and atmospheric attenuation which focus on nonselective scattering during heavy rainfall condition in Malaysian environment. Malaysian weather data are used to reflect the conditions particularly in tropical regions. Results: We have presented the results of 16-channels WDM at 100-GHz channel spacing. The simulated results show that this system can support a higher bit rate up to 2.5 Gbps over 2.4 km distance. Conclusion: Simulation results showed that WDM FSO system may be a good candidate to solve the last mile problem and also it has capability to accommodate the channels more than 16. By introducing the error correction code or balance detection, the transmission distance might be increased further.

  8. HST hot Jupiter Transmission Spectral Survey: A detection of Na and strong optical absorption in HAT-P-1b

    CERN Document Server

    Nikolov, N; Pont, F; Burrows, A S; Fortney, J J; Ballester, G E; Evans, T M; Huitson, C M; Wakeford, H R; Wilson, P A; Aigrain, S; Deming, D; Gibson, N P; Henry, G W; Knutson, H; Etangs, A Lecavelier des; Showman, A P; Vidal-Madjar, A; Zahnle, K

    2013-01-01

    We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on HST observations, covering the spectral regime from 0.29 to 1.027{\\mu}m with STIS, which is coupled with a recent WFC3 transit (1.087 to 1.687{\\mu}m). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55{\\mu}m, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3{\\sigma} significance level, but find no evidence for the potassium feature. The red data implies a marginally flat spectrum with a tentative absorption enhancement at wavelength longer than ~0.85{\\mu}m. The STIS and WFC3 spectra differ significantly in absolute radius level (4.3 +/- 1.6 pressure scale heights), implying strong optical absorption in the atmosphere of HAT-P-1b. The optical to near-infrared difference cannot be explained by stellar activity, as simulta- neous st...

  9. 107 Gb/s coherent optical OFDM transmission over 1000-km SSMF fiber using orthogonal band multiplexing.

    Science.gov (United States)

    Shieh, W; Yang, Q; Ma, Y

    2008-04-28

    Coherent optical OFDM (CO-OFDM) has emerged as an attractive modulation format for the forthcoming 100 Gb/s Ethernet. However, even the spectral-efficient implementation of CO-OFDM requires digital-to-analog converters (DAC) and analog-to-digital converters (ADC) to operate at the bandwidth which may not be available today or may not be cost-effective. In order to resolve the electronic bandwidth bottleneck associated with DAC/ADC devices, we propose and elucidate the principle of orthogonal-band-multiplexed OFDM (OBM-OFDM) to subdivide the entire OFDM spectrum into multiple orthogonal bands. With this scheme, the DAC/ADCs do not need to operate at extremely high sampling rate. The corresponding mapping to the mixed-signal integrated circuit (IC) design is also revealed. Additionally, we show the proof-of-concept transmission experiment through optical realization of OBM-OFDM. To the best of our knowledge, we present the first experimental demonstration of 107 Gb/s QPSK-encoded CO-OFDM signal transmission over 1000 km standard-single- mode-fiber (SSMF) without optical dispersion compensation and without Raman amplification. The demonstrated system employs 2x2 MIMO-OFDM signal processing and achieves high electrical spectral efficiency with direct-conversion at both transmitter and receiver.

  10. One-way optical transmission in silicon photonic crystal heterojunction with circular and square scatterers

    Science.gov (United States)

    Liu, Dan; Hu, Sen; Gao, Yihua

    2017-07-01

    A 2D orthogonal square-lattice photonic crystal (PC) heterojunction consisting of circular and square air holes in silicon is presented. Band structures are calculated using the plane wave expansion method, and the transmission properties are investigated by the finite-different time-domain simulations. Thanks to the higher diffraction orders excited when the circular and square holes are interlaced along the interface, one-way transmission phenomena can exist within wide frequency regions. The higher order diffraction is further enhanced through two different interface optimization designs proposed by modifying the PC structure of the hetero-interface. An orthogonal PC heterojunction for wide-band and efficient one-way transmission is constructed, and the maximum transmissivity is up to 78%.

  11. Hole-assisted multicore optical fiber for next generation telecom transmission systems

    Science.gov (United States)

    Ziolowicz, A.; Szymanski, M.; Szostkiewicz, L.; Tenderenda, T.; Napierala, M.; Murawski, M.; Holdynski, Z.; Ostrowski, L.; Mergo, P.; Poturaj, K.; Makara, M.; Slowikowski, M.; Pawlik, K.; Stanczyk, T.; Stepien, K.; Wysokinski, K.; Broczkowska, M.; Nasilowski, T.

    2014-08-01

    We present a multicore fiber dedicated for next generation transmission systems. To overcome the issue of multicore fibers' integration with existing transmission systems, the fiber is designed in such a way that the transmission parameters for each core (i.e., chromatic dispersion, attenuation, bending loss, etc.) are in total accordance with the obligatory standards for telecommunication single core fibers (i.e., ITU-T G.652 and G.657). We show the results of numerical investigations and measurements carried out for the fabricated fiber, which confirm low core-to-core crosstalk and compatibility with standard single-core single-mode transmission links making the fiber ready for implementation in the near future.

  12. 40  Gb/s DWDM Structure with Optical Phase Configuration for Long-Haul Transmission System

    Science.gov (United States)

    Lin, Hsiu-Sheng; Lai, Po-Chou

    2017-03-01

    We propose the experimental transport of 48 channels with 40 Gbit/s dense wavelength-division multiplexing (DWDM) system that uses single-mode fiber (SMF) in combination with dispersion compensation fiber (DCF) which is a dispersion compensation device, in C and L band wavelength range to solve the dispersion program. The DWDM system scheme employing single Mach-Zehnder modulation (MZM) return-to-zero differential phase-shift keying (RZ-DPSK) modulation format with hybrid Raman/EDFA (Erbium-doped fiber amplifier) configuration to improve transmission signal, and employing an optical phase conjugation (OPC) configuration in the middle line. That can compensate for dispersion impairment and improve nonlinear effects to investigate transmission distance performances.

  13. 19-core MCF transmission system using EDFA with shared core pumping coupled via free-space optics.

    Science.gov (United States)

    Sakaguchi, Jun; Klaus, Werner; Puttnam, Benjamin J; Mendinueta, José Manuel Delgado; Awaji, Yoshinari; Wada, Naoya; Tsuchida, Yukihiro; Maeda, Koichi; Tadakuma, Masateru; Imamura, Katsunori; Sugizaki, Ryuichi; Kobayashi, Tetsuya; Tottori, Yusaku; Watanabe, Masayuki; Jensen, R V

    2014-01-13

    We report the development of a space division multiplexed (SDM) transmission system consisting of a 19-core fiber and 19-core Erbium-doped fiber amplifier (EDFA). A new 19-core fiber with an improved core arrangement was employed to achieve a low aggregated inter-core crosstalk of -42 dB at 1550 nm over 30 km. The EDFA uses shared free-space optics for pump beam combining and isolation, thus is SDM transparent and has some potential for cost reduction. 19.6 dB to 23.3 dB gain and 6.0 dB to 7.0 dB noise figure were obtained for each SDM channel at 1550 nm. System feasibility for SDM transmission over 1200 km was demonstrated with 100 Gb/s PDM-QPSK signals.

  14. Invited Paper: Optical fibers for the transmission of orbital angular momentum modes

    Science.gov (United States)

    Brunet, Charles; Rusch, Leslie A.

    2016-09-01

    Orbital angular momentum (OAM) of light is a promising means for exploiting the spatial dimension of light to increase the capacity of optical fiber links. We summarize how OAM enables efficient mode multiplexing for optical communications, with emphasis on the design of OAM fibers.

  15. Modeling the transmission and thermal emission in a pupil image behind the Keck II adaptive optics system

    Science.gov (United States)

    Arriaga, Pauline; Fitzgerald, Michael P.; Lyke, James E.; Campbell, Randall D.; Wizinowich, Peter L.; Adkins, Sean M.; Matthews, Keith Y.

    2016-08-01

    The design and performance of astronomical instruments depend critically on the total system throughput as well as the background emission from the sky and instrumental sources. In designing a pupil stop for background- limited imaging, one seeks to balance throughput and background rejection to optimize measurement signal-to-noise ratios. Many sources affect transmission and emission in infrared imaging behind the Keck Observatory's adaptive optics systems, such as telescope segments, segment gaps, secondary support structure, and AO bench optics. Here we describe an experiment, using the pupil-viewing mode of NIRC2, to image the pupil plane as a function of wavelength. We are developing an empirical model of throughput and background emission as a function of position in the pupil plane. This model will be used in part to inform the optimal design of cold pupils in future instruments, such as the new imaging camera for OSIRIS.

  16. Image fiber optic space-CDMA parallel transmission experiment using 8 x 8 VCSEL/PD arrays.

    Science.gov (United States)

    Nakamura, Moriya; Kitayama, Ken-ichi; Igasaki, Yasunori; Shamoto, Naoki; Kaneda, Keiji

    2002-11-10

    We experimentally demonstrate space-code-division multiple access (space-CDMA) based twodimensional (2-D) parallel optical interconnections by using image fibers and 8 x 8 vertical-cavity surface-emitting laser (VCSEL)/photo diode (PD) arrays. Two spatially encoded four-bit (2 x 2) parallel optical signals were emitted fiom 2-D VCSEL arrays and transmitted through image fibers. The encoded signals were multiplexed by an image-fiber coupler and detected by a 2-D PD array on the receiver side. The receiver recovered the intended parallel signal by decoding the signal. The transmission speed was 64 Mbps/ch (total throughput: 512 Mbps). Bit-error-rate (BER) measurement with a laterally misaligned PD array showed the array had a misalignment tolerance of 25 microm for a BER performance of 10(-9).

  17. Transmission and pass-drop operations of mixed baudrate Nyquist OTDM-WDM signals for all-optical elastic network.

    Science.gov (United States)

    Tan, Hung Nguyen; Inoue, Takashi; Kurosu, Takayuki; Namiki, Shu

    2013-08-26

    We propose the use of Nyquist OTDM-WDM signal for highly efficient, fully elastic all-optical networks. With the possibility of generation of ultra-coarse yet flexible granular channels, Nyquist OTDM-WDM can eliminate guard-bands in conventional WDM systems, and hence improves the spectral efficiency in network perspective. In this paper, transmission and pass-drop operations of mixed baudrate Nyquist OTDM-WDM channels from 43 Gbaud to dual-polarization 344 Gbaud are successfully demonstrated over 320 km fiber link with four FlexGrid-compatible WSS nodes. A stable clock recovery is also carried out for different baudrate Nyquist OTDMs by optical null-header insertion technique.

  18. Experimental demonstration of 30 Gb/s direct-detection optical OFDM transmission with blind symbol synchronisation using virtual subcarriers.

    Science.gov (United States)

    Bouziane, R; Milder, P A; Erkılınç, S; Galdino, L; Kilmurray, S; Thomsen, B C; Bayvel, P; Killey, R I

    2014-02-24

    The paper investigates the performance of a blind symbol synchronisation technique for optical OFDM systems based on virtual subcarriers. The test-bed includes a real-time 16-QAM OFDM transmitter operating at a net data rate of 30.65 Gb/s using a single OFDM band with a single FPGA-DAC subsystem and demonstrates transmission over 23.3 km SSMF with direct detection at a BER of 10(-3). By comparing the performance of the proposed synchronisation scheme with that of the Schmidl and Cox algorithm, it was found that the two approaches achieve similar performance for large numbers of averaging symbols, but the performance of the proposed scheme degrades as the number of averaging symbols is reduced. The proposed technique has lower complexity and bandwidth overhead as it does not rely on training sequences. Consequently, it is suitable for implementation in high speed optical OFDM transceivers.

  19. Experimental Investigation on Transmission Control Protocol Throughput Behavior in Optical Fiber Access Networks

    Science.gov (United States)

    Tego, Edion; Matera, Francesco; del Buono, Donato

    2016-03-01

    This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.

  20. Strong optical transmission through the ellipsoid metal-film nanohole arrays

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The transmission characteristics of a metallic film with subwavelength ellipsoid nanohole arrays are investigated by using the three-dimensional finite-difference time-domain (3D-FDTD) method. The extraordinary transmission is attributed to the collaboration of localized waveguide resonance and surface plasmon resonance. The influences of the lattice constant and the hole shape on the transmission are studied. By analyzing the picture of electric field and electromagnetic energy distribution, we show the mechanisms of the two different resonances: Localized waveguide resonance mode can be confined inside the ellipsoid holes region, while electric field and electromagnetic energy are localized separately at the two ends of ellipsoid holes for the surface plasma resonance mode.

  1. Bandpass transmission filters based on phase shifted fiber Bragg gratings in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Ortega, Beatriz; Min, Rui; Sáez-Rodri­guez, David

    2017-01-01

    In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moir......é structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability...

  2. QoS-guaranteed burst transmission for VoIP service over optical burst switching networks

    Science.gov (United States)

    Tachibana, Takuji; Kasahara, Shoji

    2007-08-01

    We propose a burst transmission method that guarantees the voice over Internet protocol (VoIP) service. The proposed method consists of three techniques: round-robin burst assembly with slotted scheduling, priority control with void filling, and hop-based preemption. Each technique is utilized so that the burst loss probability and the burst transmission delay satisfy VoIP quality of service (QoS). We evaluate by simulation the performance of the proposed method in NSFNET with 14 nodes. Numerical examples show that our proposed method is effective for guaranteeing the VoIP QoS while accommodating a large number of VoIP users.

  3. Construction tolerances for low loss, dielectric coated, metallic waveguide for transmission optical radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sandweiss, J.

    1984-08-01

    The transmission of radiation, in a specific mode of interest for the IFELA, past a symmetric step in dielectric coating thickness has been calculated. The result shows that the transmission loss depends on the quantity (s/D)/sup 2/ and vanishes to first order in the ratio of the step s to the guide aperture D. With the reasonable assumption that this feature holds for all forms of surface imperfections, the attenuation length due to imperfections has been estimated. It is found that rms surface roughness of approx. 0.1 ..mu.. m leads to attenuation lengths of 25 km or greater.

  4. Four-dimensional optical multiband-OFDM for beyond 1.4 Tb/s serial optical transmission.

    Science.gov (United States)

    Djordjevic, Ivan; Batshon, Hussam G; Xu, Lei; Wang, Ting

    2011-01-17

    We propose a four-dimensional (4D) coded multiband-OFDM scheme suitable for beyond 1.4 Tb/s serial optical transport. The proposed scheme organizes the N-dimensional (ND) signal constellation points in the form of signal matrix; employs 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and exploits both orthogonal polarizations. This scheme can fully exploit advantages of OFDM to deal with chromatic dispersion, PMD and PDL effects; and multidimensional signal constellations to improve OSNR sensitivity of conventional optical OFDM. The improvement of 4D-OFDM over corresponding polarization-multiplexed QAM (with the same number of constellation points) ranges from 1.79 dB for 16 signal constellation point-four-dimensional-OFDM (16-4D-OFDM) up to 4.53 dB for 128-4D-OFDM.

  5. Low-Driving-Voltage Optical Modulation Utilizing FWM for High-Speed Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    Akihiko; Matsuura; Toshiya; Matsuda; Tomoyoshi; Kataoka

    2003-01-01

    We propose an optical transmitter with reduced modulator driving voltage. This reduction is achieved through an on-off ratio improvement technique based on FWM. We confirmed the feasibility of the method in a 43-Gbit/s experiment.

  6. Performance analysis of MRC spatial diversity receiver system for satellite-to-ground downlink optical transmissions

    Science.gov (United States)

    Li, Kangning; Ma, Jing; Tan, Liying; Yu, Siyuan; Cao, Yubin

    2016-10-01

    The performances of satellite-to-ground downlink optical communications over Gamma-Gamma distributed turbulence are studied for multiple apertures receiver system. Maximum ratio combining (MRC) technique is considered as a combining scheme to mitigate the atmospheric turbulence under thermal noise limited conditions. Bit-error rate (BER) performances for on-off keying (OOK) modulated direct detection optical communications are analyzed for MRC diversity receptions through an approximation method. To show the net diversity gain of multiple apertures receiver system, BER performances of MRC receiver system are compared with a single monolithic aperture receiver system with the same total aperture area (same average total incident optical power) for satellite-to-ground downlink optical communications. All the numerical results are also verified by Monte-Carlo (MC) simulations.

  7. O-band 400 Gbit/s client side optical transmission link

    DEFF Research Database (Denmark)

    Zuo, Tianjian; Tatarczak, Anna; Iglesias Olmedo, Miguel

    2014-01-01

    We present an O-band 400 Gbit/s optical client side Ethernet link with 40 km SSMF reach employing four LAN-WDM lanes, MultiCAP modulation and direct detection.......We present an O-band 400 Gbit/s optical client side Ethernet link with 40 km SSMF reach employing four LAN-WDM lanes, MultiCAP modulation and direct detection....

  8. Modeling and performance analysis of IP access interface in optical transmission networks with packet switching

    OpenAIRE

    Lackovic, Marko; Bungarzeanu, Cristian

    2006-01-01

    The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet ...

  9. Optical vortex beam transmission with different OAM in scattering beads and brain tissue media

    Science.gov (United States)

    Wang, W. B.; Shi, Lingyan; Lindwasser, Lukas; Marque, Paulo; Lavery, M. P. J.; Alfano, R. R.

    2016-03-01

    Light transmission of Laguerre Gaussian (LG) vortex beams with different orbital angular momentum (OAM) values (L) in scattering beads and mouse brain tissue media were experimentally investigated for the first time in comparison with Gaussian (G) beams. The LG beams with different OAM were generated using a spatial light modulator (SLM) in reflection mode. The scattering beads media consist of various sizes and concentrations of latex beads in water solutions. The transmissions of LG and G beams through scattering beads and brain tissue media were measured with different ratios of sample thicknesses (z) to scattering mean free path (ls) of the turbid media, z/ls. The results indicate that within the ballistic region where z/ls is small, the LG and G beams show no significant difference, while in the diffusive region where z/ls is higher, the vortex beams show higher transmission than G beams. In the diffusive region, the LG beams with higher L values show higher transmission than the beams with lower L values due to the eigen channels in the media. The transition points from the ballistic to diffusive regions for different scattering beads and brain tissue media were studied.

  10. Broadband behavior of transmission volume holographic optical elements for solar concentration.

    Science.gov (United States)

    Bañares-Palacios, Paula; Álvarez-Álvarez, Samuel; Marín-Sáez, Julia; Collados, María-Victoria; Chemisana, Daniel; Atencia, Jesús

    2015-06-01

    A ray tracing algorithm is developed to analyze the energy performance of transmission and phase volume holographic lenses that operate with broadband illumination. The agreement between the experimental data and the theoretical treatment has been tested. The model has been applied to analyze the optimum recording geometry for solar concentration applications.

  11. Measurement of optical refraction-, transmission- and turbulence effects in the False Bay, South Africa; June 2007

    NARCIS (Netherlands)

    Jong, A.N. de; Schwering, P.B.W.; Fritz, P.J.

    2008-01-01

    Complementary to a measurement campaign of small surface targets in the False Bay, South Africa [1], a set-up could be arranged of atmospheric propagation experiments. This opportunity allowed us to collect another set of transmission data in a coastal area, where the environmental conditions are

  12. HfO2/SiO2 multilayer based reflective and transmissive optics from the IR to the UV

    Science.gov (United States)

    Wang, Jue; Hart, Gary A.; Oudard, Jean Francois; Wamboldt, Leonard; Roy, Brian P.

    2016-05-01

    HfO2/SiO2 multilayer based reflective optics enable threat detection in the short-wave/middle-wave infrared and high power laser targeting capability in the near infrared. On the other hand, HfO2/SiO2 multilayer based transmissive optics empower early missile warning by taking advantage of the extremely low noise light detection in the deep-ultraviolet region where solar irradiation is strongly absorbed by the ozone layer of the earth's atmosphere. The former requires high laser damage resistance, whereas the latter needs a solar-blind property, i.e., high transmission of the radiation below 290 nm and strong suppression of the solar background from 300 nm above. The technical challenges in both cases are revealed. The spectral limits associated with the HfO2 and SiO2 films are discussed and design concepts are schematically illustrated. Spectral performances are realized for potential A and D and commercial applications.

  13. Moldable AR microstructures for improved laser transmission and damage resistance in CIRCM fiber optic beam delivery systems

    Science.gov (United States)

    MacLeod, Bruce D.; Hobbs, Douglas S.; Sabatino, Ernest, III

    2011-06-01

    Anti-reflecting (AR) surface relief microstructures (ARMs) are being developed as a replacement for thin-film AR coatings in laser-based systems to improve light transmission, power handling, operational bandwidth, and system reliability. Because ARMs textures have the potential to be replicated using simple embossing methods, the performance advantage and robustness of ARMs can be extended to moldable mid-infrared transmitting materials such as chalcogenide optical fibers. In this work, the optical performance of mid-infrared transparencies incorporating ARMs textures replicated from a master template has been modeled, and multiple master stamping tools have been fabricated in materials such as diamond, silicon carbide, nickel, silicon, and sapphire. Images from ARMs texture embossing trials using arsenic sulfide and arsenic selenide (AMTIR2) glasses, and fluoride glasses such as ZBLAN and indium fluoride provided by IRPhotonics, show excellent pattern transfer and fidelity. Transmission measurements of ARMs textures stamped into arsenic sulfide and arsenic selenide windows show broadband infrared performance equivalent to ARMs textured windows processed by direct patterning and etch methods. A system for molding ARMs textures directly into the end facets of multi-mode mid-infrared transmitting fibers is yielding promising initial results.

  14. Fluorescence-enhanced optical spectroscopy using early arriving photons in transmission mode: a finite element approach

    Science.gov (United States)

    Piron, Vianney; L'Huillier, Jean-Pierre

    2012-06-01

    Optical imaging of turbid media is a challenging problem mainly due to the scattering process that reduces image contrast and degrades spatial resolution. The development of fluorescent probes has recently improved the noninvasive optical technique. In this paper, we are interested in the time gating fluorescence signals. The diffusion approximation is used in order to describe the light propagation of a laser pulse in a turbid media that mimics breast like biological tissue. A numerical model based on a finite element method is proposed. Fluorescence time dependent numerical simulations are performed in order to compute time-gated intensities resulting from line scans across partially absorbing and scattering slab configurations. Optical properties of embedded objects are chosen to be the same as optical properties of breast tumor. Tacking into account two hidden objects, we investigate the lateral resolution aimed by fluorescence modality, and we also compared the results to thus obtained by photon propagation. Different widths of the time gate are computed and it is demonstrated that both lateral localization of one inclusion, and resolution of two inclusions, are enhanced when the time-gate width (▵t) is decreased. The overall computations confirm that fluorescent time-gating technique is very sensitive to local variations in optical properties that are due to breast-like tumors in turbid media.

  15. Linear and Nonlinear Impairment Compensation in Coherent Optical Transmission with Digital Signal Processing

    DEFF Research Database (Denmark)

    Porto da Silva, Edson

    Digital signal processing (DSP) has become one of the main enabling technologies for the physical layer of coherent optical communication networks. The DSP subsystems are used to implement several functionalities in the digital domain, from synchronization to channel equalization. Flexibility...... nonlinearity compensation, (II) spectral shaping, and (III) adaptive equalization. For (I), original contributions are presented to the study of the nonlinearity compensation (NLC) with digital backpropagation (DBP). Numerical and experimental performance investigations are shown for different application...... scenarios. Concerning (II), it is demonstrated how optical and electrical (digital) pulse shaping can be allied to improve the spectral confinement of a particular class of optical time-division multiplexing (OTDM) signals that can be used as a building block for fast signaling single-carrier transceivers...

  16. An optical study of amorphous (Se{sub 80}Te{sub 20}){sub 100-x}Ge{sub x} thin films using their transmission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Mainika; Thakur, Nagesh [Department of Physics, H P University, Summer Hill Shimla, HP-171005 (India); Sharma, Pankaj; Katyal, S C [Department of Physics, Jaypee University of Information Technology, Waknaghat-173215 (India)], E-mail: mainika_phy@rediffmail.com, E-mail: pankaj.sharma@juit.ac.in

    2008-12-07

    Optical constants (refractive index and extinction coefficient) have been studied for a-(Se{sub 80}Te{sub 20}){sub 100-x}Ge{sub x} (x = 0, 2, 4, 6) thin films using transmission spectra in the wavelength range 500-2500 nm. It is observed from optical transmission measurements that the optical energy gap (E{sub g}) increases while the refractive index (n) and the extinction coefficient (k) decrease with the incorporation of Ge in the Se-Te system. The increase in the optical energy gap is interpreted by correlating the optical energy gap with the decrease in electronegativity and increase in the heat of atomization (H{sub s}). The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model.

  17. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses.

    Science.gov (United States)

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-09-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals.

  18. Regular and anomalous extraordinary optical transmission at the THz-gap.

    Science.gov (United States)

    Kuznetsov, S A; Navarro-Cía, M; Kubarev, V V; Gelfand, A V; Beruete, M; Campillo, I; Sorolla, M

    2009-07-06

    In this paper Anomalous Extraordinary Transmission (ET) is reported for s-polarization of low loss doubly periodic subwavelength hole arrays patterned on polypropylene (PP) substrates by conventional contact photolithography at the so-called THz-gap (1-10 THz). The unexpected enhanced transmittance for s-polarization (i.e. without spoof plasmons) was previously numerically demonstrated in subwavelength slits arrays. However, subsequently no experimental work has been devoted to this unexpected Extraordinary Transmission neither in subwavelength slits nor in subwavelength holes. Here, numerical study and experimental results of the Anomalous ET and the symmetric and antisymmetric transmittance modes associated with the already well-known p-polarization ET are shown alongside a systematically analysis of the frequency peaks as a function of hole size for both incident polarizations.

  19. Mitigation of nonlinear transmission effects for OFDM 16-QAM optical signal using adaptive modulation.

    Science.gov (United States)

    Skidin, Anton S; Sidelnikov, Oleg S; Fedoruk, Mikhail P; Turitsyn, Sergei K

    2016-12-26

    The impact of the fiber Kerr effect on error statistics in the nonlinear (high power) transmission of the OFDM 16-QAM signal over a 2000 km EDFA-based link is examined. We observed and quantified the difference in the error statistics for constellation points located at three power-defined rings. Theoretical analysis of a trade-off between redundancy and error rate reduction using probabilistic coding of three constellation power rings decreasing the symbol-error rate of OFDM 16-QAM signal is presented. Based on this analysis, we propose to mitigate the nonlinear impairments using the adaptive modulation technique applied to the OFDM 16-QAM signal. We demonstrate through numerical modelling the system performance improvement by the adaptive modulation for the large number of OFDM subcarriers (more than 100). We also show that a similar technique can be applied to single carrier transmission.

  20. Packaged semiconductor laser optical phase locked loop for photonic generation, processing and transmission of microwave signals

    DEFF Research Database (Denmark)

    Langley, L.N.; Elkin, M.D.; Edege, C.

    1999-01-01

    In this paper, we present the first fully packaged semiconductor laser optical phase-locked loop (OPLL) microwave photonic transmitter. The transmitter is based on semiconductor lasers that are directly phase locked without the use of any other phase noise-reduction mechanisms. In this transmitter...

  1. FABRICATION OF TRANSMISSIVE DIFFRACTIVE OPTICAL ELEMENTS FOR THE MID-INFRARED WITH A LASER WRITING INSTRUMENT

    Directory of Open Access Journals (Sweden)

    S. Calixto

    2007-08-01

    Full Text Available A simple method to fabricate infrared (λ = 10.6 μm diffractive optical elements that work in a transmissionmode is presented. A laser-writing instrument completely under computer control has been built todemonstrate the feasibility of this method. Several diffractive elements, fabricated using the laser-writinginstrument, are described.

  2. Frequency Domain Training-Aided Channel Estimation and Equalization in Time-Varying Optical Transmission Systems

    DEFF Research Database (Denmark)

    Pittalà, Fabio; Msallem, Majdi; Hauske, Fabian N.;

    2012-01-01

    We propose a non-weighted feed-forward equalization method with filter update by averaging channel estimations based on short CAZAC sequences. Three averaging methods are presented and tested by simulations in a time-varying 2×2 MIMO optical system....

  3. Numerical analysis of transmission efficiency for parabolic optical fiber nano-probe.

    Science.gov (United States)

    Zhu, Wei; Shi, Tielin; Tang, Zirong; Gong, Bo; Liao, Guanglan; Liu, Shiyuan

    2013-11-18

    Theoretical calculations are performed for the transmission efficiencies of parabolic nano-probes with different shapes, based on the finite element method. It shows that the transmittance will fluctuate dramatically with the variation of either wavelength or probe shape, and the efficiency could be rather high even at long wavelengths. Subsequently, we thoroughly investigate this phenomenon and find that these fluctuations are due to the joint effect of light propagating modes and surface plasmon polaritons modes. It indicates that high transmittance can be achieved with the selection of appropriate wavelength and probe structure.

  4. The Development of Advanced Optical Fibers for Long-Wave Infrared Transmission

    Directory of Open Access Journals (Sweden)

    Pierre Lucas

    2013-12-01

    Full Text Available Long-wave infrared fibers are used in an increasing number of applications ranging from thermal imaging to bio-sensing. However, the design of optical fiber with low-loss in the far-infrared requires a combination of properties including good rheological characteristics for fiber drawing and low phonon energy for wide optical transparency, which are often mutually exclusive and can only be achieved through fine materials engineering. This paper presents strategies for obtaining low loss fibers in the far-infrared based on telluride glasses. The composition of the glasses is systematically investigated to obtained fibers with minimal losses. The fiber attenuation is shown to depend strongly on extrinsic impurity but also on intrinsic charge carrier populations in these low band-gap amorphous semiconductor materials.

  5. High power free space optical link for rapid energy and data transmission

    Science.gov (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake; Kwok, Philip

    2016-05-01

    Design and experimental data for a high power laser diode based free space point-to-point optical power/data link is presented. In time critical power up applications, such as providing power and guidance information to a munition shell just prior to deployment, energy of the order of 100 J needs to be transferred in under 10 s. Current inductive technology is slow and broadcasts a radio-frequency signal which is undesirable for stealth operation. Rapid energy transfer times require high irradiance levels at the surface of the photovoltaic cells, typically, exceeding 1000X suns. Through efficient thermal design of heat sinks, high optical to electrical power conversion efficiencies of 50%, which are usually attainable at low power levels of 1 W, are achievable at higher power levels.

  6. Optical fiber link for transmission of 1-nJ femtosecond laser pulses at 1550 nm

    DEFF Research Database (Denmark)

    Eichhorn, Finn; Olsson, Rasmus Kjelsmark; Buron, Jonas Christian Due

    2010-01-01

    We report on numerical and experimental characterization of the performance of a fiber link optimized for the delivery of sub-100-fs laser pulses at 1550 nm over several meters of fiber. We investigate the power handling capacity of the link, and demonstrate all-fiber delivery of 1-nJ pulses over...... a distance of 5.3 m. The fiber link consists of dispersion-compensating fiber (DCF) and standard single-mode fiber. The optical pulses at different positions in the fiber link are measured using frequency-resolved optical gating (FROG). The results are compared with numerical simulations of the pulse...... propagation based on the generalized nonlinear Schrödinger equation. The high input power capacity of the fiber link allows the splitting and distribution of femtosecond pulses to an array of fibers with applications in multi-channel fiber-coupled terahertz time-domain spectroscopy and imaging systems. We...

  7. Adaptive 4~64 QAM real-time coherent optical transmission over 320 km with FPGA-based transmitter and receiver.

    Science.gov (United States)

    Yoshida, Masato; Hirooka, Toshihiko; Kasai, Keisuke; Nakazawa, Masataka

    2014-06-30

    We demonstrate the first real-time adaptive optical coherent QAM transmission with variable multiplicities (4-, 16- and 64-QAM) using an FPGA-based transmitter and receiver. Rate-variable transmission (20~60 Gbit/s) was successfully achieved with a polarization multiplexing scheme at 5 Gsymbol/s over 320 km, where the OSNR margins were increased by 9 and 17 dB, respectively, by changing the modulation level from 64 to 16 and 4.

  8. Seamless Translation of Optical Fiber PolMux-OFDM into a 2x2 MIMO Wireless Transmission Enabled by Digital Training-Based Fiber-Wireless Channel Estimation

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Zhao, Ying; Deng, Lei

    2011-01-01

    We propose and demonstrate a 2 × 2 multiple-input multiple-output (MIMO) wireless over fiber transmission system. Seamless translation of two orthogonal frequency division multiplexing (OFDM) signals on dual optical polarization states into wireless MIMO transmission at 795.5 Mbit/s net data rate...... is enabled by using digital training-based channel estimation. A net spectral efficiency of 2.55 bit/s/Hz is achieved....

  9. Fiber Optic Cryogenic Sensors for Superconducting Magnets and Superconducting Power Transmission lines at CERN

    CERN Document Server

    Chiuchiolo, A; Cusano, A; Bajko, M; Perez, J C; Bajas, H; Giordano, M; Breglio, G; Palmieri, L

    2014-01-01

    The design, fabrication and tests of a new generation of superconducting magnets for the upgrade of the LHC require the support of an adequate, robust and reliable sensing technology. The use of Fiber Optic Sensors is becoming particularly challenging for applications in extreme harsh environments such as ultra-low temperatures, high electromagnetic fields and strong mechanical stresses offering perspectives for the development of technological innovations in several applied disciplines.

  10. Performance evaluation of optical channel transmission between UAVs and Ground Stations

    Directory of Open Access Journals (Sweden)

    Hatziefremidis Antonis

    2016-01-01

    Full Text Available Free space optical (FSO communications links is a promising solution for the provision of high data rate point to point communications. In particular deploying FSO technology for mobile links between Unmanned Aerial Vehicles (UAVs and fixed Ground Stations (GS introduces several interesting challenges. In this paper, we investigate the ability of a mobile FSO system to operate in different atmospheric conditions. Specifically, we characterize the quality of the optical channel with a proper model in terms of Bit Error Rate (BER and average Signal to Noise Ratio (SNR and we report a detailed optical amplification model able to support a constant Quality of Service for different distances from 1 km up to 35 km at 10 Gbps with 1550 nm wavelength. An extensive comparative analysis among different FSO configurations links considering the altitude of the UAV, the wavelength and the atmospheric conditions is provided. The results show that there is degradation at the BER over a slanted path compared to a horizontal path at the same conditions.

  11. Metallic attenuated total reflection infrared hollow fibers for robust optical transmission systems

    Science.gov (United States)

    Jing, Chengbin; Guo, Hong; Hu, Zhigao; Yang, Pingxiong; Chu, Junhao; Liu, Aiyun; Shi, Yiwei

    2014-07-01

    A durable metallic attenuated total reflection (ATR) hollow fiber (bore size: 1.45 mm, wall thickness: 50 μm) was designed and fabricated based on a nickel capillary tube and hexagonal germanium dioxide (GeO2). The anomalous dispersion of the hexagonal GeO2 layer grown inside a nickel tube achieves low-loss light transmission at two peak-power wavelengths for CO2 laser devices (10.2 and 10.6 μm). An 11-28 W, 10.2 or 10.6 μm CO2 laser power was steadily delivered via a fiber elastically bent from 0° to 90° (radius: 45 cm) for over 40 min (transmission loss: 0.22 to 4.2 dB/m). Theoretically fitting the measured temperatures showed that front-end clipping caused greater thermal loading than the distributed mode absorption. The maximum external temperature of a nickel ATR fiber is much lower than that of a silica glass ATR fiber owing to their different heat dissipation abilities. The HE11 mode purity of the output beam profiles decreased from 90.3% to 44.7% as the bending angle increased from 0° to 90°. Large core sizes and wall roughnesses (scattering loss 0.04 dB/m) contributed to mode mixing and excess losses that were above the value predicted by the classical Marcatili and Schmeltzer equation (0.024-0.037 dB/m).

  12. Cryogenic Fiber Optic Sensors for Superconducting Magnets and Power Transmission Lines in High Energy Physics Applications

    CERN Document Server

    AUTHOR|(CDS)2081689; Bajko, Marta

    In the framework of the Luminosity upgrade of the Large Hadron Collider (HL - LHC), a remarkable R&D effort is now ongoing at the European Organization for Nuclear Research (CERN) in order to develop a new generation of accelerator magnets and superconducting power transmission lines. The magnet technology will be based on Nb3Sn enabling to operate in the 11 - 13 T range. In parallel, in order to preserve the power converters from the increasing radiation level, high power transmission lines are foreseen to feed the magnets from free - radiation zones. These will be based on high temperature superconductors cooled down with helium gas in the range 5 - 30 K. The new technologies will require advanced design and fabrication approaches as well as adapted instrumentation for monitoring both the R&D phase and operation. Resistive sensors have been used so far for voltage, temperature and strain monitoring but their integration still suffers from the number of electrical wires and the complex compensation o...

  13. Optimal modulation formats for 2 560 km optical transmission with low power penalty

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong; ZHANG Feng; CAO Jihong; QIN Xi; LU Bo; LU Dan; CHEN Ming; JIAN Shuisheng

    2007-01-01

    The production mechanism of non-return-to-zero (NRZ),return-to-zero (RZ) and carrier suppressed returnto-zero (CSRZ) was analyzed theoretically in this paper.We compared the transmission performance of CSRZ with RZ and NRZ formats at 10 Gb/s system by numerical simulation.And we simulated the transmission model constructed with Erbium-doped fiber amplifier (EDFA) as the solo amplifier and the chirped fiber Bragg grating (CFBG) as the solo dispersion compensator used in the system.A practical 8×10 Gb/s 2 560 km transmitted experiment was conducted in straight line with these different modulation formats mentioned above and the experiment results show very good agreement with the result of computer simulation.The CSRZ format is more effective than other formats in the system,and involved only 2.5 dB power penalty cost in the practical 2 560 km error-free experiment.The results also show that CSRZ will help to optimize the transmitted results and reduce the transmitted penalty further.

  14. A transmission line model for propagation in elliptical core optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Georgantzos, E.; Boucouvalas, A. C. [Department of Telecommunications and Informatics, University of Peloponnese, Karaiskaki 70, 221 00, Tripoli Greece (Greece); Papageorgiou, C. [Department of Electrical Engineering, National technical University of Athens, Iroon Politechniou 9, Kaisariani, 16121, Athens (Greece)

    2015-12-31

    The calculation of mode propagation constants of elliptical core fibers has been the purpose of extended research leading to many notable methods, with the classic step index solution based on Mathieu functions. This paper seeks to derive a new innovative method for the determination of mode propagation constants in single mode fibers with elliptic core by modeling the elliptical fiber as a series of connected coupled transmission line elements. We develop a matrix formulation of the transmission line and the resonance of the circuits is used to calculate the mode propagation constants. The technique, used with success in the case of cylindrical fibers, is now being extended for the case of fibers with elliptical cross section. The advantage of this approach is that it is very well suited to be able to calculate the mode dispersion of arbitrary refractive index profile elliptical waveguides. The analysis begins with the deployment Maxwell’s equations adjusted for elliptical coordinates. Further algebraic analysis leads to a set of equations where we are faced with the appearance of harmonics. Taking into consideration predefined fixed number of harmonics simplifies the problem and enables the use of the resonant circuits approach. According to each case, programs have been created in Matlab, providing with a series of results (mode propagation constants) that are further compared with corresponding results from the ready known Mathieu functions method.

  15. Time domain zero-padding based adaptive-PAM signal transmission with high spectral efficiency in IMDD optical communication system

    Science.gov (United States)

    Zhang, Fangliu; He, Jing; Deng, Rui; Cheng, Yun; Xiao, Minlei; Chen, Lin

    2016-08-01

    In this paper, an adaptive pulse amplitude modulation (APAM) scheme is proposed and experimentally demonstrated in the intensity-modulation and direct-detection (IMDD) optical communications system. In the proposed scheme, the channel is divided into two sub-channels, and different PAM mapping can be chosen for different sub-channel according to the fading conditions. In addition, the 20-km standard single mode fiber (SSMF) transmission of 24 Gbit/s 16/4-APAM signal with the spectral efficiency (SE) up to 6 bit/s/Hz is experimentally demonstrated. The experiment results show that the bit error rate (BER) of the 16/4-APAM signal can be achieved less than 2.4e-2.

  16. Transmission stabilization and destabilization involving Kerr and Raman effects in broadband soliton-based fiber optics systems

    CERN Document Server

    Peleg, Avner; Tran, Thinh P

    2015-01-01

    We study stabilization and destabilization of propagating soliton sequences in broadband fiber optics systems with $N$ frequency channels, taking into account second-order dispersion, Kerr nonlinearity, delayed Raman response, and linear gain-loss. We employ a propagation model consisting of a system of $N$ coupled nonlinear Schr\\"odinger (NLS) equations and a reduced $N$-dimensional predator-prey model for amplitude dynamics. Numerical simulations with the coupled-NLS model with $2 \\le N \\le 4$ show stable oscillatory dynamics of soliton amplitudes at short-to-intermediate distances, in agreement with predictions of the predator-prey model. Furthermore, the main destabilizing mechanism at long distances is due to generation of radiative sidebands, where the sidebands for a given channel form at the frequencies of solitons in the neighboring channels. This destabilizing process can be partially mitigated by employing frequency dependent linear gain-loss. Moreover, significant enhancement of transmission stabi...

  17. Study of laser deposited W/Si multilayers for high-resolution transmission X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, Christian; Doering, Florian; Liese, Tobias; Krebs, Hans-Ulrich [Institut fuer Materialphysik, Georg-August-University, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

    2012-07-01

    High quality non-periodic W/Si multilayers were pulsed laser deposited (PLD) at 248 nm for the use as high-resolution transmission X-ray optics (multilayer Laue lenses) and studied by thickness monitoring, SEM, TEM, and X-ray reflectometry (XRR). Due to the large difference in melting point, the ablation threshold, deposition rate as well as droplet formation of the both components W and Si strongly differ. Furthermore, during deposition of W/Si multilayers thickness deficits up to 2 nm due to resputtering and WSi{sub 2} interlayers occur. Thus, in order to ensure a defined deposition of high-quality multilayers, two distinct element specific sets of optimized preparation conditions had to be worked out. In this contribution, this process of optimization is described in detail and the underlying mechanisms are discussed, also in comparison with SRIM simulations.

  18. 1.28 Tbit/s/channel single-polarization DQPSK transmission over 525 km using ultrafast time-domain optical Fourier transformation

    DEFF Research Database (Denmark)

    Guan, P.; Mulvad, Hans Christian Hansen; Tomiyama, Y.;

    2010-01-01

    A single-channel 1.28 Tbit/s transmission over 525 km is demonstrated for the first time with a single-polarization DQPSK signal. Ultrafast time-domain optical Fourier transformation is successfully applied to DQPSK signals and results in improved performance and increased system margin.......A single-channel 1.28 Tbit/s transmission over 525 km is demonstrated for the first time with a single-polarization DQPSK signal. Ultrafast time-domain optical Fourier transformation is successfully applied to DQPSK signals and results in improved performance and increased system margin....

  19. 0.48Tb/s (12x40Gb/s) WDM transmission and high-quality thermo-optic switching in dielectric loaded plasmonics

    DEFF Research Database (Denmark)

    Kalavrouziotis, Dimitrios; Papaioannou, S.; Giannoulis, Giannis;

    2012-01-01

    through BER measurements by exploiting the heterointegration of a 60 mu m-long straight DLSPPW on a Silicon-on-Insulator waveguide platform, showing error-free performance for six out of the twelve channels. High-quality thermo-optic tuning has been achieved by utilizing Cycloaliphatic......We demonstrate Wavelength Division Multiplexed (WDM)-enabled transmission of 480Gb/s aggregate data traffic (12x40Gb/s) as well as high-quality 1x2 thermo-optic tuning in Dielectric-Loaded Surface Plasmon Polariton Waveguides (DLSPPWs). The WDM transmission characteristics have been verified......-Acrylate-Polymer as an efficient thermo-optic polymer loading employed in a dual-resonator DLSPPW switching structure, yielding a 9nm wavelength shift and extinction ratio values higher than 10dB at both output ports when heated to 90 degrees C. (C)2012 Optical Society of America...

  20. Selective optical control of synaptic transmission in the subcortical visual pathway by activation of viral vector-expressed halorhodopsin.

    Directory of Open Access Journals (Sweden)

    Katsuyuki Kaneda

    Full Text Available The superficial layer of the superior colliculus (sSC receives visual inputs via two different pathways: from the retina and the primary visual cortex. However, the functional significance of each input for the operation of the sSC circuit remains to be identified. As a first step toward understanding the functional role of each of these inputs, we developed an optogenetic method to specifically suppress the synaptic transmission in the retino-tectal pathway. We introduced enhanced halorhodopsin (eNpHR, a yellow light-sensitive, membrane-targeting chloride pump, into mouse retinal ganglion cells (RGCs by intravitreously injecting an adeno-associated virus serotype-2 vector carrying the CMV-eNpHR-EYFP construct. Several weeks after the injection, whole-cell recordings made from sSC neurons in slice preparations revealed that yellow laser illumination of the eNpHR-expressing retino-tectal axons, putatively synapsing onto the recorded cells, effectively inhibited EPSCs evoked by electrical stimulation of the optic nerve layer. We also showed that sSC spike activities elicited by visual stimulation were significantly reduced by laser illumination of the sSC in anesthetized mice. These results indicate that photo-activation of eNpHR expressed in RGC axons enables selective blockade of retino-tectal synaptic transmission. The method established here can most likely be applied to a variety of brain regions for studying the function of individual inputs to these regions.

  1. Signal transmission in a human body medium-based body sensor network using a Mach-Zehnder electro-optical sensor.

    Science.gov (United States)

    Song, Yong; Hao, Qun; Zhang, Kai; Wang, Jingwen; Jin, Xuefeng; Sun, He

    2012-11-30

    The signal transmission technology based on the human body medium offers significant advantages in Body Sensor Networks (BSNs) used for healthcare and the other related fields. In previous works we have proposed a novel signal transmission method based on the human body medium using a Mach-Zehnder electro-optical (EO) sensor. In this paper, we present a signal transmission system based on the proposed method, which consists of a transmitter, a Mach-Zehnder EO sensor and a corresponding receiving circuit. Meanwhile, in order to verify the frequency response properties and determine the suitable parameters of the developed system, in-vivo measurements have been implemented under conditions of different carrier frequencies, baseband frequencies and signal transmission paths. Results indicate that the proposed system will help to achieve reliable and high speed signal transmission of BSN based on the human body medium.

  2. Signal Transmission in a Human Body Medium-Based Body Sensor Network Using a Mach-Zehnder Electro-Optical Sensor

    Directory of Open Access Journals (Sweden)

    Yong Song

    2012-11-01

    Full Text Available The signal transmission technology based on the human body medium offers significant advantages in Body Sensor Networks (BSNs used for healthcare and the other related fields. In previous works we have proposed a novel signal transmission method based on the human body medium using a Mach-Zehnder electro-optical (EO sensor. In this paper, we present a signal transmission system based on the proposed method, which consists of a transmitter, a Mach-Zehnder EO sensor and a corresponding receiving circuit. Meanwhile, in order to verify the frequency response properties and determine the suitable parameters of the developed system, in-vivo measurements have been implemented under conditions of different carrier frequencies, baseband frequencies and signal transmission paths. Results indicate that the proposed system will help to achieve reliable and high speed signal transmission of BSN based on the human body medium.

  3. Active photonic sensor communication cable for field application of optical data and power transmission

    Science.gov (United States)

    Suthau, Eike; Rieske, Ralf; Zerna, Thomas

    2014-10-01

    Omitting electrically conducting wires for sensor communication and power supply promises protection for sensor systems and monitored structures against lightning or high voltages, prevention of explosion hazards, and reduction of susceptibility to tampering. The ability to photonically power remote systems opens up the full range of electrical sensors. Power-over-fiber is an attractive option in electromagnetically sensitive environments, particularly for longterm, maintenance-free applications. It can deliver uninterrupted power sufficient for elaborate sensors, data processing or even actuators alongside continuous high speed data communication for remote sensor application. This paper proposes an active photonic sensor communication system, which combines the advantages of optical data links in terms of immunity to electromagnetic interference (EMI), high bandwidth, hardiness against tampering or eavesdropping, and low cable weight with the robustness one has come to expect from industrial or military electrical connectors. An application specific integrated circuit (ASIC) is presented that implements a closed-loop regulation of the sensor power supply to guarantee continuous, reliable data communications while maintaining a highly efficient, adaptive sensor supply scheme. It is demonstrated that the resulting novel photonic sensor communication cable can handle sensors and actuators differing orders of magnitude with respect to power consumption. The miniaturization of the electro-optical converters and driving electronics is as important to the presented development as the energy efficiency of the detached, optically powered sensor node. For this reason, a novel photonic packaging technology based on wafer-level assembly of the laser power converters by means of passive alignment will be disclosed in this paper.

  4. Nonlinear inverse synthesis for high spectral efficiency transmission in optical fibers

    CERN Document Server

    Le, Son Thai; Turitsyn, Sergei K

    2014-01-01

    In linear communication channels, spectral components (modes) defined by the Fourier transform of the signal propagate without interactions with each other. In certain nonlinear channels, such as the one modelled by the classical nonlinear Schr\\"odinger equation, there are nonlinear modes (nonlinear signal spectrum) that also propagate without interacting with each other and without corresponding nonlinear cross talk; effectively, in a linear manner. Here, we describe in a constructive way how to introduce such nonlinear modes for a given input signal. We investigate the performance of the nonlinear inverse synthesis (NIS) method, in which the information is encoded directly onto the continuous part of the nonlinear signal spectrum. This transmission technique, combined with the appropriate distributed Raman amplification, can provide an effective eigenvalue division multiplexing with high spectral efficiency, thanks to highly suppressed channel cross talk. The proposed NIS approach can be integrated with any...

  5. Optical transmission photometry of the highly inflated exoplanet WASP-17b

    CERN Document Server

    Bento, J; Copperwheat, C M; Fortney, J J; Dhillon, V S; Hickman, R; Littlefair, S P; Marsh, T R; Parsons, S G; Southworth, J

    2013-01-01

    We present ground-based high-precision observations of the transit of WASP-17b using the multi-band photometer ULTRACAM on ESO's NTT in the context of performing transmission spectrophotometry of this highly inflated exoplanet. Our choice of filters (SDSS u', g' and r' bands) is designed to probe for the presence of opacity sources in the upper atmosphere. We find evidence for a wavelength dependence in the planet radius in the form of enhanced absorption in the SDSS r' band, consistent with a previously detected broad sodium feature. We present a new independent measurement of the planetary radius at Rpl = 1.97 +/- 0.06 Rjup, which confirms this planet as the most inflated exoplanet known to date. Our measurements are most consistent with an atmospheric profile devoid of enhanced TiO opacity, previously predicted to be present for this planet.

  6. Performance Analysis of High-speed Optical Pulse Transmission in Dispersion-managed Nonlinear Birefringent Fiber Using Quantum Well Laser Diode Sources

    Institute of Scientific and Technical Information of China (English)

    YAN Minhui; CHEN Jianping

    2002-01-01

    This paper analyzes the high bit-rate optical pulse trasmission in single mode optical fiber with chromatic dispersion, polarization mode dispersion (small random birefringence) and nonlinearity. Numerical method employed can precisely describe their interactive effect on transmission performance. Different dispersion maps and the related performance are analysed. Various simulation results and discussion are given. The results show that chromatic dispersion compensation should be carefully designed. Appropriate dispersion management can also alleviate the effect of polarization mode dispersion.

  7. Optical fiber link for transmission of 1-nJ femtosecond laser pulses at 1550 nm.

    Science.gov (United States)

    Eichhorn, Finn; Olsson, Rasmus Kjelsmark; Buron, Jonas C D; Grüner-Nielsen, Lars; Pedersen, Jens Engholm; Jepsen, Peter Uhd

    2010-03-29

    We report on numerical and experimental characterization of the performance of a fiber link optimized for the delivery of sub-100-fs laser pulses at 1550 nm over several meters of fiber. We investigate the power handling capacity of the link, and demonstrate all-fiber delivery of 1-nJ pulses over a distance of 5.3 m. The fiber link consists of dispersion-compensating fiber (DCF) and standard single-mode fiber. The optical pulses at different positions in the fiber link are measured using frequency-resolved optical gating (FROG). The results are compared with numerical simulations of the pulse propagation based on the generalized nonlinear Schrödinger equation. The high input power capacity of the fiber link allows the splitting and distribution of femtosecond pulses to an array of fibers with applications in multi-channel fiber-coupled terahertz time-domain spectroscopy and imaging systems. We demonstrate THz pulse generation and detection using a distributed fiber link with 32 channels and 2.6 nJ input pulse energy.

  8. High Speed 1.55 μm Lasers for Fiber Optic Transmission

    Science.gov (United States)

    Morton, Paul A.

    This paper describes the essential elements for creating a practical wide bandwidth directly modulated laser source. This includes considerations of the intrinsic limitations of the laser structure, due to the resonant frequency and damping of the laser output, together with carrier transport issues to allow carriers in the device active region to be efficiently modulated at high speeds. The use of a P-doped compressively strained multiple-quantum well active region to provide high intrinsic speed and remove transport limitations is described, together with record setting results of 25 GHz modulation bandwidth for a 1.55 μm Fabry-Perot laser and 26 GHz bandwidth for a 1.55 μm DFB laser. The challenges of providing high bandwidth electrical connections to the laser on a suitable submount, together with fiber attachment and microwave packaging are discussed. Results of fully packaged 1.55 μm DFB lasers with 25 GHz modulation bandwidth are shown. Digital modulation of the packaged 1.55 μm DFB including impedance matching is described, and the transient wavelength chirp is presented. This low chirp is reduced further using an optical filter, to provide a 10 GBit/s source that can transmit error free over 38.5 km of standard optical fiber.

  9. Compact photonic crystal circulator with flat-top transmission band created by cascading magneto-optical resonance cavities.

    Science.gov (United States)

    Wang, Qiong; Ouyang, Zhengbiao; Lin, Mi; Liu, Qiang

    2015-11-20

    A new type of compact three-port circulator with flat-top transmission band (FTTB) in a two-dimensional photonic crystal has been proposed, through coupling the cascaded magneto-optical resonance cavities to waveguides. The coupled-mode theory is applied to investigate the coupled structure and analyze the condition to achieve FTTB. According to the theoretical analysis, the structure is further optimized to ensure that the condition for achieving FTTB can be satisfied for both cavity-cavity coupling and cavity-waveguide coupling. Through the finite-element method, it is demonstrated that the design can realize a high quality, nonreciprocal circulating propagation of waves with an insertion loss of 0.023 dB and an isolation of 23.3 dB, covering a wide range of operation frequency. Such a wideband circulator has potential applications in large-scale integrated photonic circuits for guiding or isolating harmful optical reflections from load elements.

  10. Bundled hollow optical fibers for transmission of high-peak-power Q-switched Nd:YAG laser pulses.

    Science.gov (United States)

    Yilmaz, Ozgur; Miyagi, Mitsunobu; Matsuura, Yuji

    2006-09-20

    A hollow-fiber bundle was designed and used to deliver high-peak-power pulses from a Q-switched Nd:YAG laser. An 80 cm long bundle with a total diameter of 5.5 mm was composed of 37 glass capillaries with bore diameters of 0.7 mm. Beam-resizing optics with two lenses were used to couple the laser beam into the bundle. The measured coupling loss due to the limited aperture ratio of the bundle was 2.3 dB, and the transmission loss at wavelengths of 1064 and 532 nm was 0.3 dB. When an inert gas flowed through the bores of the capillaries, the maximum output pulse energy was 200 mJ, which was the limit of the laser used in the experiment. Hollow-fiber bundles withstand irradiation better than single hollow fibers and silica-glass optical fibers do. They are suitable for many dermatological applications because they can be used to irradiate a large area.

  11. Diffuse optical fluorescence tomography using time-resolved data acquired in transmission

    Science.gov (United States)

    Leblond, Frederic; Fortier, Simon; Friedlander, Michael P.

    2007-02-01

    We present an algorithm using data acquired with a time-resolved system with the goal of reconstructing sources of fluorescence emanating from the deep interior of highly scattering biological tissues. A novelty in our tomography algorithm is the integration of a light transport model adapted to rodent geometries. For small volumes, our analysis suggest that neglecting the index of refraction mismatch between diffusive and non-diffusive regions, as well as the curved nature of the boundary, can have a profound impact on fluorescent images and spectroscopic applications relying on diffusion curve fitting. Moreover, we introduce a new least-squares solver with bound constraints adapted for optical problems where a physical non-negative constraint can be imposed. Finally, we find that maximizing the time-related information content of the data in the reconstruction process significantly enhances the quality of fluorescence images. Preliminary noise propagation and detector placement optimization analysis are also presented.

  12. In vitro application of optical transmission systems in erbium:YAG laser temporomandibular joint surgery

    Science.gov (United States)

    Nuebler-Moritz, Michael; Hering, Peter; Niederdellmann, Herbert; Deuerling, Christian; Dammer, Ralf

    1995-05-01

    The experimental setup of this study is focused on the changes in temporomandibular joint tissue after irradiation with an Erbium:YAG laser. Initially, the free-running beam from the laser was focused onto freshly excised porcine tissue samples, indicating an optimum average energy density and pulse duration for the purpose of temporomandibular joint surgery of about 15 - 60 J/cm2 and 120 microsecond(s) - 240 microsecond(s) , respectively. Consecutively, an attempt was made to couple the Erbium:YAG laser beam on the one hand to optical fibers made of infrared-transmitting glasses (fluoride- and chalcogenide-based), on the other hand to a recently developed sapphire and liquid core fiber, respectively. From the preliminary observations of this investigation it appears that both the liquid core and the sapphire fiber are the most promising candidates for delivery of Erbium-YAG laser radiation in arthroscopic surgery of the craniomandibular articulation.

  13. Advanced digital signal processing for short haul optical fiber transmission beyond 100G

    Science.gov (United States)

    Kikuchi, Nobuhiko

    2017-01-01

    Significant increase of intra and inter data center traffic has been expected by the rapid spread of various network applications like SNS, IoT, mobile and cloud computing, and the needs for ultra-high speed and cost-effective short- to medium-reach optical fiber links beyond 100-Gbit/s is becoming larger and larger. Such high-speed links typically use multilevel modulation to lower signaling speed, which in turn face serious challenges in limited loss budget and waveform distortion tolerance. One of the promising techniques to overcome them is the use of advanced digital signal processing (DSP) and we review various DSP applications for short-to-medium reach applications.

  14. Multiwavelength laser light transmission of hollow optical fiber from the visible to the mid-infrared

    Science.gov (United States)

    Shi, Yi Wei; Ito, Kentaro; Matsuura, Yuji; Miyagi, Mitsunobu

    2005-11-01

    We report on low-loss multiwavelength laser delivery of hollow optical fiber in a wide wavelength region, from the visible to the infrared. Improved methods of liquid-phase coating were used to fabricate the hollow fiber with inner films of a silver and a cyclic olefin polymer (COP) layer. The surface roughness of the silver layer was reduced dramatically by pretreatment on the inner glass surface with an SnCl2 solution. The COP layer roughness was also decreased by using an ambient atmosphere of tetrahydrofuran (THF) solvent during the COP layer formation. Owing to the smooth surfaces, hollow fiber with optimum COP film thickness for CO2 laser light simultaneously yields low losses for a Er:YAG laser and a red pilot beam. The power durability of CO2 and Er:YAG lasers, as well as the loss properties for the pilot beam, is demonstrated.

  15. Multiwavelength laser light transmission of hollow optical fiber from the visible to the mid-infrared.

    Science.gov (United States)

    Shi, Yi Wei; Ito, Kentaro; Matsuura, Yuji; Miyagi, Mitsunobu

    2005-11-01

    We report on low-loss multiwavelength laser delivery of hollow optical fiber in a wide wavelength region, from the visible to the infrared. Improved methods of liquid-phase coating were used to fabricate the hollow fiber with inner films of a silver and a cyclic olefin polymer (COP) layer. The surface roughness of the silver layer was reduced dramatically by pretreatment on the inner glass surface with an SnCl2 solution. The COP layer roughness was also decreased by using an ambient atmosphere of tetrahydrofuran (THF) solvent during the COP layer formation. Owing to the smooth surfaces, hollow fiber with optimum COP film thickness for CO2 laser light simultaneously yields low losses for a Er:YAG laser and a red pilot beam. The power durability of CO2 and Er:YAG lasers, as well as the loss properties for the pilot beam, is demonstrated.

  16. Optical retrodirective tracking system approach using an array of phase conjugators for communication and power transmission.

    Science.gov (United States)

    Schäfer, Christian A; Matoba, Osamu; Kaya, Nobuyuki

    2007-07-20

    A new concept for a retrodirective tracking system applicable for communication and power transmission is proposed. In the proposed concept, the power transmitter utilizes a receiver's pilot signal to obtain information about its direction by conjugating the signal's phase inside a nonlinear medium. Power is therefore transmitted back to the receiver by the phase-conjugated signal beam. The power can be concentrated by an array of phase conjugators, which provides a large aperture so that the intensity can be increased on the receiver's photovoltaic panels compared to a single element. Controlling the phase and the direction of the readout beams in the four-wave-mixing process provides control over the interference pattern, its position, and its size. A numerical analysis is given for the phase and spot size control, and measurements with two Co-doped Sr(x)Ba(1-x)Nb(2)O(6) (Co:SBN) crystals confirm the occurrence of interference that is achieved for the case of two beams.

  17. Adaptation of AMO-FBMC-OQAM in optical access network for accommodating asynchronous multiple access in OFDM-based uplink transmission

    Science.gov (United States)

    Jung, Sun-Young; Jung, Sang-Min; Han, Sang-Kook

    2015-01-01

    Exponentially expanding various applications in company with proliferation of mobile devices make mobile traffic exploded annually. For future access network, bandwidth efficient and asynchronous signals converged transmission technique is required in optical network to meet a huge bandwidth demand, while integrating various services and satisfying multiple access in perceived network resource. Orthogonal frequency division multiplexing (OFDM) is highly bandwidth efficient parallel transmission technique based on orthogonal subcarriers. OFDM has been widely studied in wired-/wireless communication and became a Long term evolution (LTE) standard. Consequently, OFDM also has been actively researched in optical network. However, OFDM is vulnerable frequency and phase offset essentially because of its sinc-shaped side lobes, therefore tight synchronism is necessary to maintain orthogonality. Moreover, redundant cyclic prefix (CP) is required in dispersive channel. Additionally, side lobes act as interference among users in multiple access. Thus, it practically hinders from supporting integration of various services and multiple access based on OFDM optical transmission In this paper, adaptively modulated optical filter bank multicarrier system with offset QAM (AMO-FBMC-OQAM) is introduced and experimentally investigated in uplink optical transmission to relax multiple access interference (MAI), while improving bandwidth efficiency. Side lobes are effectively suppressed by using FBMC, therefore the system becomes robust to path difference and imbalance among optical network units (ONUs), which increase bandwidth efficiency by reducing redundancy. In comparison with OFDM, a signal performance and an efficiency of frequency utilization are improved in the same experimental condition. It enables optical network to effectively support heterogeneous services and multiple access.

  18. Long-Wavelength Infrared Surface Plasmons on Ga-Doped ZnO Films Excited via 2D Hole Arrays for Extraordinary Optical Transmission (Preprint)

    Science.gov (United States)

    2013-10-01

    AFRL-RY-WP-TP-2013-0180 LONG-WAVELENGTH INFRARED SURFACE PLASMONS ON Ga- DOPED ZnO FILMS EXCITED VIA 2D HOLE ARRAYS FOR EXTRAORDINARY OPTICAL...TITLE AND SUBTITLE LONG-WAVELENGTH INFRARED SURFACE PLASMONS ON Ga- DOPED ZnO FILMS EXCITED VIA 2D HOLE ARRAYS FOR EXTRAORDINARY OPTICAL TRANSMISSION...structure size such as period. Pulse laser deposited Ga- doped ZnO has been shown to have fluctuations in optical and electrical parameters based on

  19. Thermometer by optical fiber for ampacity studies in overhead transmission lines; Termometro a fibra optica para estudo da ampacidade em linhas de transmissao aereas

    Energy Technology Data Exchange (ETDEWEB)

    Valente, L.C.G.; Kawase, L.R.; Silva Filho, J.I. da; Silva, J.M.M. da [Centro de Pesquisas de Energia Eletrica, Rio de Janeiro, RJ (Brazil); Igarashi, A.Y. [Universidade Federal, Rio de Janeiro, RJ (Brazil)

    1995-12-31

    This article suggests the utilization of thermometers constructed from optical fibers technology in overhead power transmission lines. This will help the studies in progress about the electric power systems ampacity. It also presents the advantages of using optical fibers instead of conventional thermometers. As an example, the fact that the optical fibers are dielectric and make possible the remote monitoring. It is also shown a possibility of introducing such measuring system in electric junctions where OPGW cables are used 4 refs., 4 figs.; e-mail: liliana at fis.puc-rio.br

  20. Transmission lines with lightning arresters cables energized by optical fibers; Linhas de transmissao com cabos para-raios energizados com fibra optica

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Fumitaka; Cicarelli, Liliane Dias [Alcoa Aluminio S.A. (Brazil); D`Ajuz, Ary [ELETRONORTE, Belem, PA (Brazil); Martinez, Manuel L.B. [Escola Federal de Engenharia de Itajuba, MG (Brazil); Masuda, Mario [Tecname Engenharia (Brazil)

    1995-12-31

    Recently, the implementation of optical systems has been possible through the utilization of the existent transmission lines structure by the sharing between electric power and telecommunications enterprises, using Op-GW cables instead of conventional lightning-arresters cables. In order to make such optical sharing feasible, the enterprise ALCOA Aluminio S.A is developing the energized lightning-arrester system with optical fiber in it. This work presents such system and show its great advantages specially when implemented in low population density regions in order to supply electric power demand at lower costs 6 refs., 5 figs.

  1. Design of Excess 3 to BCD code converter using electro-optic effect of Mach-Zehnder Interferometers for efficient data transmission

    Science.gov (United States)

    Kumar, Santosh; Chanderkanta; Amphawan, Angela

    2016-04-01

    Excess 3 code is one of the most important codes used for efficient data storage and transmission. It is a non-weighted code and also known as self complimenting code. In this paper, a four bit optical Excess 3 to BCD code converter is proposed using electro-optic effect inside lithium-niobate based Mach-Zehnder interferometers (MZIs). The MZI structures have powerful capability to switching an optical input signal to a desired output port. The paper constitutes a mathematical description of the proposed device and thereafter simulation using MATLAB. The study is verified using beam propagation method (BPM).

  2. 110 km transmission of 160 Gbit/s RZ-DQPSK signals by midspan polarization-insensitive optical phase conjugation in a Ti:PPLN waveguide

    DEFF Research Database (Denmark)

    Hu, Hao; Nouroozi, R.; Ludwig, R.;

    2010-01-01

    We demonstrate 160Gbit/s return-to-zero (RZ) differential quarternary phase-shift keying (DQPSK) signal transmission over a 110km single-mode fiber by taking advantage of mid-span optical phase conjugation (OPC). The technique is based on nonlinear wavelength conversion by cascaded second harmonic...

  3. Full-duplex bidirectional transmission of 10-Gb/s millimeter-wave QPSK signal in E-band optical wireless link.

    Science.gov (United States)

    Fang, Yuan; Yu, Jianjun; Chi, Nan; Xiao, Jiangnan

    2014-01-27

    We experimentally demonstrated full-duplex bidirectional transmission of 10-Gb/s millimeter-wave (mm-wave) quadrature phase shift keying (QPSK) signal in E-band (71-76 GHz and 81-86 GHz) optical wireless link. Single-mode fibers (SMF) are connected at both sides of the antenna for uplink and downlink which realize 40-km SMF and 2-m wireless link for bidirectional transmission simultaneously. We utilized multi-level modulation format and coherent detection in such E-band optical wireless link for the first time. Mm-wave QPSK signal is generated by photonic technique to increase spectrum efficiency and received signal is coherently detected to improve receiver sensitivity. After the coherent detection, digital signal processing is utilized to compensate impairments of devices and transmission link.

  4. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    CERN Document Server

    Gan, K K; Kagan, H P; Kass, R D; Moore, J R; Smith, D S; Wiese, A; Ziolkowskic, M; 10.1088/1748-0221/5/12/C12006

    2010-01-01

    We have designed two ASICs for possible applications in the optical links of a new layer of the pixel detector to be install inside the ATLAS Pixel detector for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for the VCSEL and a receiver/decoder to decode the signal received at the PIN diode to extract the data and clock. Both ASICs contain 4 channels for operation with a VCSEL or PIN array. The ASICs were designed using a 130 nm CMOS process to enhance the radiation-hardness. We have characterized the fabricated ASICs and the performance of the ASICs is satisfactory. The receiver/decoder can properly decode the bi-phase marked input stream with low PIN current and the driver can operate a VCSEL up to ~ 5 Gb/s. The added functionalities are also successful, including redundancy to bypass a broken VCSEL or PIN channel, individual control of VCSEL current, and power-on reset circuit to set all VCSEL currents to a nominal value. The ASICs were irradiated to a dose of 46 Mrad ...

  5. Experimental transmission of quantum digital signatures over 90 km of installed optical fiber using a differential phase shift quantum key distribution system

    Science.gov (United States)

    Collins, Robert J.; Amiri, Ryan; Fujiwara, Mikio; Honjo, Toshimori; Shimizu, Kaoru; Tamaki, Kiyoshi; Takeoka, Masahiro; Andersson, Erika; Buller, Gerald S.; Sasaki, Masahide

    2016-11-01

    Quantum digital signatures apply quantum mechanics to the problem of guaranteeing message integrity and non-repudiation with information-theoretical security, which are complementary to the confidentiality realized by quantum key distribution. Previous experimental demonstrations have been limited to transmission distances of less than 5-km of optical fiber in a laboratory setting. Here we report the first demonstration of quantum digital signatures over installed optical fiber as well as the longest transmission link reported to date. This demonstration used a 90-km long differential phase shift quantum key distribution system to achieve approximately one signed bit per second - an increase in the signature generation rate of several orders of magnitude over previous optical fiber demonstrations.

  6. Experimental transmission of quantum digital signatures over 90  km of installed optical fiber using a differential phase shift quantum key distribution system.

    Science.gov (United States)

    Collins, Robert J; Amiri, Ryan; Fujiwara, Mikio; Honjo, Toshimori; Shimizu, Kaoru; Tamaki, Kiyoshi; Takeoka, Masahiro; Andersson, Erika; Buller, Gerald S; Sasaki, Masahide

    2016-11-01

    Quantum digital signatures (QDSs) apply quantum mechanics to the problem of guaranteeing message integrity and non-repudiation with information-theoretical security, which are complementary to the confidentiality realized by quantum key distribution (QKD). Previous experimental demonstrations have been limited to transmission distances of less than 5 km of optical fiber in a laboratory setting. Here we report, to the best of our knowledge, the first demonstration of QDSs over installed optical fiber, as well as the longest transmission link reported to date. This demonstration used a 90 km long differential phase shift QKD to achieve approximately one signed bit per second, an increase in the signature generation rate of several orders of magnitude over previous optical fiber demonstrations.

  7. Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission

    Science.gov (United States)

    Wu, Jindong; Chen, Liuhua; Li, Qingguo; Wu, Wenwen; Sun, Keyuan; Wu, Xingkun

    2011-07-01

    Four non-zero-dispersion-shifted fibers with almost the same large effective area (Aeff) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An Aeff of greater than 71 μm2 is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550nm dispersion slope from 0.072ps/nm2/km to 0.063ps/nm2/km or 0.05ps/nm2/km, increasing the 1550nm dispersion from 4.972ps/nm/km to 5.679ps/nm/km or 7.776ps/nm/km, and shifting the zero-dispersion wavelength from 1500nm to 1450nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550nm dispersion slope from 0.12ps/nm2/km to 0.085ps/nm2/km, increasing the 1550nm dispersion from -4ps/nm/km to -6.016ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.

  8. Carrier Synchronization for 3-and 4-bit-per-Symbol Optical Transmission

    Science.gov (United States)

    Ip, Ezra; Kahn, Joseph M.

    2005-12-01

    We investigate carrier synchronization for coherent detection of optical signals encoding 3 and 4 bits/symbol. We consider the effects of laser phase noise and of additive white Gaussian noise (AWGN), which can arise from local oscillator (LO) shot noise or LO-spontaneous beat noise. We identify 8-and 16-ary quadrature amplitude modulation (QAM) schemes that perform well when the receiver phase-locked loop (PLL) tracks the instantaneous signal phase with moderate phase error. We propose implementations of 8-and 16-QAM transmitters using Mach-Zehnder (MZ) modulators. We outline a numerical method for computing the bit error rate (BER) of 8-and 16-QAM in the presence of AWGN and phase error. It is found that these schemes can tolerate phase-error standard deviations of 2.48° and 1.24°, respectively, for a power penalty of 0.5 dB at a BER of 10-9. We propose a suitable PLL design and analyze its performance, taking account of laser phase noise, AWGN, and propagation delay within the PLL. Our analysis shows that the phase error depends on the constellation penalty, which is the mean power of constellation symbols times the mean inverse power. We establish a procedure for finding the optimal PLL natural frequency, and determine tolerable laser linewidths and PLL propagation delays. For zero propagation delay, 8-and 16-QAM can tolerate linewidth-to-bit-rate ratios of 1.8 × 10-5 and 1.4 × 10-6, respectively, assuming a total penalty of 1.0 dB.

  9. Synchronic, optical transmission data link integrated with FPGA circuits (for TESLA LLRF control system)

    Energy Technology Data Exchange (ETDEWEB)

    Zielinski, J.S.

    2006-07-15

    The X-ray free-electron laser X-FEL that is being planned at the DESY research center in cooperation with European partners will produce high-intensity ultra-short X-ray flashes with the properties of laser light. This new light source, which can only be described in terms of superlatives, will open up a whole range of new possibilities for the natural sciences. It could also offer very promising opportunities for industrial users. SIMCON (SIMulator and CONtroller) is the project of the fast, low latency digital controller dedicated to the LLRF1 system in VUV FEL experiment It is being developed by the ELHEP2 group in the Institute of Electronic Systems at Warsaw University of Technology. The main purpose of the project is to create a controller to stabilize the vector sum of fields in cavities of one cryo-module in the experiment. The device can be also used as the simulator of the cavity and test bench for other devices. The synchronic, optical link project was made for the accelerator X-FEL laser TESLA, the LLRF control system experiment at DESY, Hamburg. The control and diagnostic data is transmitted up to 2.5Gbit/s through a plastic fiber in a distance up to a few hundred meters. The link is synchronized once after power up, and never resynchronized when data is transmitted with maximum speed. The one way link bit error rate is less then 10{sup -15}. The transceiver component written in VHDL that works in the dedicated Altera registered Stratix registered GX FPGA circuit. During the work in the PERG laboratory a 2,5Gbit/s serial link with the long vector parallel interface transceiver was created. Long-Data-Vector transceiver transmits 16bit vector each 8ns with 120ns latency. (orig.)

  10. 巨型数字阵列光传输系统设计%Design of Huge-DAR Fiber-optic Transmission System

    Institute of Scientific and Technical Information of China (English)

    王查散; 王东岳; 高文辉

    2013-01-01

    光传输技术是数字阵列雷达系统中的重要技术,主要实现高精度的定时同步和高速海量的数据传输。巨型数字阵列由于阵面规模大、组件数量多,加大了光传输系统设计的技术复杂度和工程实现难度。文中首先分析了巨型数字阵列信号传输的特点和具体要求,给出了巨型数字阵列光传输系统的设计方案和技术途径,对系统中的光纤传输网络、高速串行传输和系统测试等关键技术进行了详细分析,通过采用PON、SERDES等多项先进技术解决了设计中的技术难点,最终实现了巨型数字阵列的光传输系统设计。%Optical transmission technology is an important technique of digital array radar system,it is mainly to realize high-precision timing synchronization and high-speed and massive amounts of data transmission. Due to some characteristics including large scale and more components of giant digital array,technical complexity and engineering realized difficulties of system design for optical transmission have been widely increased. First analyze the signal transmission characteristics and some specific requirements of giant digital array,then put forward the design schemes and the technological approaches of optical transmission design,next analyze some key techniques inclu-ding optical fiber transmission network,high-speed serial transmission,system testing and so forth in detail,meanwhile,solve the techni-cal difficulties of design by adopting PON,SERDES and many advanced technologies,finally realize the system design of optical trans-mission for giant digital array.

  11. 55th electric science promotion prize (progress prize). Demonstration of optical soliton transmission on OPGW first in the world; Dai 55 kai denki gakujutsu shinkosho (shinposho) jusho. Seiaihatsu no OPGW ni okeru hikari soriton denso no jissho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-10

    Electric science promotion prize (progress prize) is given to `Person who newly proposed a new concept, theory, material, device, system and method on electrical science and technology, or demonstrated these proposals` by the commendation committee of Institute of Electrical Engineers of Japan every year. Eight promotion prizes including that for Kansai Electric Power`s `Demonstration of optical soliton transmission on OPGW first in the world` were given. This research succeeded in development of the transmission/ receiving device suitable for optical soliton transmission, and the prediction method of an optimum transmission condition by computer simulation. In addition, this research succeeded in 10Gbit transmission of 784km and 40Gbit transmission (4-wave multiplex) of 392km by applying the above research result to Okurobe trunk line OPGW (98.2km). This demonstration of optical soliton transmission on OPGW is first in the world. (NEDO)

  12. Structure Prediction of Self-Assembled Dye Aggregates from Cryogenic Transmission Electron Microscopy, Molecular Mechanics, and Theory of Optical Spectra.

    Science.gov (United States)

    Friedl, Christian; Renger, Thomas; Berlepsch, Hans V; Ludwig, Kai; Schmidt Am Busch, Marcel; Megow, Jörg

    2016-09-01

    Cryogenic transmission electron microscopy (cryo-TEM) studies suggest that TTBC molecules self-assemble in aqueous solution to form single-walled tubes with a diameter of about 35 Å. In order to reveal the arrangement and mutual orientations of the individual molecules in the tube, we combine information from crystal structure data of this dye with a calculation of linear absorbance and linear dichroism spectra and molecular dynamics simulations. We start with wrapping crystal planes in different directions to obtain tubes of suitable diameter. This set of tube models is evaluated by comparing the resulting optical spectra with experimental data. The tubes that can explain the spectra are investigated further by molecular dynamics simulations, including explicit solvent molecules. From the trajectories of the most stable tube models, the short-range ordering of the dye molecules is extracted and the optimization of the structure is iteratively completed. The final structural model is a tube of rings with 6-fold rotational symmetry, where neighboring rings are rotated by 30° and the transition dipole moments of the chromophores form an angle of 74° with respect to the symmetry axis of the tube. This model is in agreement with cryo-TEM images and can explain the optical spectra, consisting of a sharp red-shifted J-band that is polarized parallel to to the symmetry axis of the tube and a broad blue-shifted H-band polarized perpendicular to this axis. The general structure of the homogeneous spectrum of this hybrid HJ-aggregate is described by an analytical model that explains the difference in redistribution of oscillator strength inside the vibrational manifolds of the J- and H-bands and the relative intensities and excitation energies of those bands. In addition to the particular system investigated here, the present methodology can be expected to aid the structure prediction for a wide range of self-assembled dye aggregates.

  13. A 30 Gb/s full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band.

    Science.gov (United States)

    Tang, Chanjuan; Yu, Jianjun; Li, Xinying; Chi, Nan; Xiao, Jiangnan; Tian, Yumin; Zhang, Junwen

    2014-01-13

    We propose and experimentally demonstrate a full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band (75-100 GHz) with the speed up to 15 Gb/s for both 95.4 GHz link and 88.6 GHz link for the first time. The generation of millimeter-wave (mm-wave) wireless signal is based on the photonic technique by heterodyne mixing of an optical quadrature-phase-shift-keying (QPSK) signal with a free-running light at different wavelength. After 20 km fiber transmission, up to 30 Gb/s mm-wave signal is delivered over 2 m wireless link, and then converted to the optical signal for another 20 km fiber transmission. At the wireless receiver, coherent detection and advanced digital signal processing (DSP) are introduced to improve receiver sensitivity and system performance. With the OSNR of 15 dB, the bit error ratios (BERs) for 10 Gb/s signal transmission at 95.4 GHz and 88.6 GHz are below the forward-error-correction (FEC) threshold of 3.8 × 10(-3) whether post filter is used or not, while the BER for 15 Gb/s QPSK signal employing post filter in the link of 95.4 GHz is 2.9 × 10(-3).

  14. Development of electron optical system using annular pupils for scanning transmission electron microscope by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Matsutani, Takaomi, E-mail: matutani@ele.kindai.ac.jp [Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502 (Japan); Yasumoto, Tsuchika; Tanaka, Takeo [Osaka Sangyo University, 3-1-1 Nakagaito, Daito, Osaka 574-8530 (Japan); Kawasaki, Tadahiro; Ichihashi, Mikio [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Ikuta, Takashi [Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa, Osaka 572-8530 (Japan)

    2012-02-01

    Annular pupils for electron optics were produced using a focused ion beam (FIB), enabling an increase in the depth of focus and allowing for aberration-free imaging and separation of the amplitude and phase images in a scanning transmission electron microscope (STEM). Simulations demonstrate that an increased focal depth is advantageous for three-dimensional tomography in the STEM. For a 200 kV electron beam, the focal depth is increased to approximately 100 nm by using an annular pupil with inner and outer semi-angles of 29 and 30 mrad, respectively. Annular pupils were designed with various outer diameters of 40-120 {mu}m and the inner diameter was designed at 80% of the outer diameter. A taper angle varying from 1 Degree-Sign to 20 Degree-Sign was applied to the slits of the annular pupils to suppress the influence of high-energy electron scattering. The fabricated annular pupils were inspected by scanning ion beam microscopy and scanning electron microscopy. These annular pupils were loaded into a STEM and no charge-up effects were observed in the scintillator projection images recorded by a CCD camera.

  15. Fast-channel LSO detectors and fiber-optic encoding for excellent dual photon transmission measurements in PET

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.F.; Moyers, J.C.; Casey, M.E.; Watson, C.C.; Nutt, R. [CTI PET Systems, Inc., Knoxville, TN (United States)

    1999-08-01

    Improved attenuation correction remains critical to PET. Currently with dual photon rotating rod sources, benefits of windowing are limited by counting losses of detectors nearest the rods, the near detectors. With single photon sources, improved statistics are offset by a greater need for collimation and more complex emission background correction. Now, a dual photon point source array with fast-channel, near detectors improves on these earlier techniques -- here, adding transmission measurement to dual-head rotating PET. Arrays of collimated point sources are aligned axially and orbit the FOV. With each source is a dedicated near detector (LSO crystal). Crystals couple to photomultipliers (PMTs). As the crystals are not ``block`` encoded, pulse-processing time is reduced (to 120 ns). Reduced processing time lowers dead time and permits hotter sources. For improved axial sampling, larger arrays (21 sources/head) may be configured. To reduce costs, crystals couple fiber-optically into unique PMT pairs -- decreasing the total number of near-detector PMTs by 71%.

  16. Single-channel 1.28 Tbit/s-525 km DQPSK transmission using ultrafast time-domain optical Fourier transformation and nonlinear optical loop mirror

    DEFF Research Database (Denmark)

    Guan, Pengyu; Mulvad, Hans Christian Hansen; Tomiyama, Yutaro

    2011-01-01

    We demonstrate a single-channel 1.28 Tbit/s-525 km transmission using OTDM of subpicosecond DQPSK signals. In order to cope with transmission impairments due to time-varying higherorder PMD, which is one of the major limiting factors in such a longhaul ultrahigh-speed transmission, we newly...

  17. On the evaluation of optical parameters of a thin semiconductor film from transmission spectra, and application to GaN films

    Science.gov (United States)

    Šantić, B.; Scholz, F.

    2008-10-01

    The analysis of the optical transmission spectra of semiconductor thin films on a transparent substrate is revisited. A new equation for the optical transmission is derived. Based on this equation and on the spacing of the interference pattern, a method is described and analyzed in detail for the determination of the film thickness, refractive index and absorption coefficient. As a notable feature, small values of the absorption coefficient can be determined as a fitting parameter at all wavelengths, regardless of strong interference. The method is compared to the frequently encountered envelope method of Manifacier et al and Swanepoel. The suitability of the method is illustrated on two GaN thin films grown on sapphire. Below the band gap, the index of refraction of GaN can be described by the equation n(λ(nm)) = 2.19 + 2.57(λ - 345)-1/2.

  18. Cross-polarization borehole radar system with a RF analog optical transmission link. Hikaridenso ni yoru chokko henpa bore hole radar keisoku system

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, T.; Sato, M.; Niitsuma, H. (Tohoku University, Sendai (Japan). Faculty of Engineering)

    1994-05-01

    The cross-polarization borehole radar system (BRS) was reported. The RF analogue optical transmission system (using the optical fiber cable) was introduced into the signal transmission between the sonde and the surface station to broaden the band and to heighten the S/N ratio. The sonde consisted of cable head (to transmit the trigger signal), receiving antenna, and transmitting antenna. The transmitting antenna was excited by the trigger signal from the surface to generate the pulse by the pulse generator. The signal received by the receiving antenna was sent to the oscilloscope on the surface. The field test of cross-polarization borehole system revealed that the effect of noise associated with the BRS employing the eccentric cable did not appear on the BRS. Examples of field test of the cross-polarization borehole measurement system employing the BRS were described. 4 refs., 8 figs., 1 tab.

  19. Properties of grain boundary networks in the NEEM ice core analyzed by combined transmission and reflection optical microscopy

    Science.gov (United States)

    Binder, Tobias; Weikusat, Ilka; Garbe, Christoph; Svensson, Anders; Kipfstuhl, Sepp

    2014-05-01

    Microstructure analysis of ice cores is vital to understand the processes controlling the flow of ice on the microscale. To quantify the microstructural variability (and thus occurring processes) on centimeter, meter and kilometer scale along deep polar ice cores, a large number of sections has to be analyzed. In the last decade, two different methods have been applied: On the one hand, transmission optical microscopy of thin sections between crossed polarizers yields information on the distribution of crystal c-axes. On the other hand, reflection optical microscopy of polished and controlled sublimated section surfaces allows to characterize the high resolution properties of a single grain boundary, e.g. its length, shape or curvature (further developed by [1]). Along the entire NEEM ice core (North-West Greenland, 2537 m length) drilled in 2008-2011 we applied both methods to the same set of vertical sections. The data set comprises series of six consecutive 6 x 9 cm2 sections in steps of 20 m - in total about 800 images. A dedicated method for automatic processing and matching both image types has recently been developed [2]. The high resolution properties of the grain boundary network are analyzed. Furthermore, the automatic assignment of c-axis misorientations to visible sublimation grooves enables us to quantify the degree of similarity between the microstructure revealed by both analysis techniques. The reliability to extract grain boundaries from both image types as well as the appearance of sublimation groove patterns exhibiting low misorientations is investigated. X-ray Laue diffraction measurements (yielding full crystallographic orientation) have validated the sensitivity of the surface sublimation method for sub-grain boundaries [3]. We introduce an approach for automatic extraction of sub-grain structures from sublimation grooves. A systematic analysis of sub-grain boundary densities indicates a possible influence of high impurity contents (amongst

  20. An optical transmission spectrum of the transiting hot Jupiter in the metal-poor WASP-98 planetary system

    Science.gov (United States)

    Mancini, L.; Giordano, M.; Mollière, P.; Southworth, J.; Brahm, R.; Ciceri, S.; Henning, Th.

    2016-09-01

    The WASP-98 planetary system represents a rare case of a hot Jupiter hosted by a metal-poor main-sequence star. We present a follow-up study of this system based on multiband photometry and high-resolution spectroscopy. Two new transit events of WASP-98 b were simultaneously observed in four passbands (g', r', i', z'), using the telescope-defocusing technique, yielding eight high-precision light curves with point-to-point scatters of less than 1 mmag. We also collected three spectra of the parent star with a high-resolution spectrograph, which we used to remeasure its spectral characteristics, in particular its metallicity. We found this to be very low, [Fe/H] = -0.49 ± 0.10, but larger than was previously reported, [Fe/H] = -0.60 ± 0.19. We used these new photometric and spectroscopic data to refine the orbital and physical properties of this planetary system, finding that the stellar and planetary mass measurements are significantly larger than those in the discovery paper. In addition, the multiband light curves were used to construct an optical transmission spectrum of WASP-98 b and probe the characteristics of its atmosphere at the terminator. We measured a lower radius at z' compared with the other three passbands. The maximum variation is between the r' and z' bands, has a confidence level of roughly 6σ and equates to 5.5 pressure scale heights. We compared this spectrum to theoretical models, investigating several possible types of atmospheres, including hazy, cloudy, cloud-free, and clear atmospheres with titanium and vanadium oxide opacities. We could not find a good fit to the observations, except in the extreme case of a clear atmosphere with TiO and VO opacities, in which the condensation of Ti and V was suppressed. As this case is unrealistic, our results suggest the presence of an additional optical-absorbing species in the atmosphere of WASP-98 b, of unknown chemical nature.

  1. 4 x 10 Gb/s terrestrial optical free space transmission over 1.2 km using an EDFA preamplifier with 100 GHz channel spacing.

    Science.gov (United States)

    Song, D Y; Hurh, Y S; Cho, J W; Lim, J H; Lee, D W; Lee, J S; Chung, Y

    2000-10-09

    We demonstrate a transmission of 4 x 10 Gb/s WDM channels over 1.2 km of free space in 1.55-microm band. The transmitted beam is coupled into a single-mode fiber through a fiber-pigtailed collimator, which enables the use of standard 100-GHz channel spacing and an optical preamplifier at the receiver. All the received channels have Q values higher than 6.

  2. Color filters based on enhanced optical transmission of subwavelength-structured metallic film for multicolor organic light-emitting diode display.

    Science.gov (United States)

    Hu, Xiao; Zhan, Li; Xia, Yuxing

    2008-08-10

    Using metallic film perforated with a subwavelength periodic structure, a novel concept of a color filter for multicolor organic light-emitting diode (OLED) display is proposed. Based on the phase-matching condition for extraordinary optical transmission, three primary color emissions can be obtained by optimizing the structure's periodicity. Two periodic structures, an array of one-dimensional periodic slits and a two-dimensional periodic hole array, are studied using coupled mode theory. Also, the feasibility of applying these structures as color filters is analyzed. The relative intensity at the unwanted wavelength, which is generated by higher resonant transmission, had been calculated to eliminate its effect on the purity of these filters. It is important that this type of color filter simultaneously solves the low emission efficiency problem for OLEDs with the aid of enhanced transmission of metal film.

  3. GABAergic transmission and chloride equilibrium potential are not modulated by pyruvate in the developing optic tectum of Xenopus laevis tadpoles.

    Directory of Open Access Journals (Sweden)

    Arseny S Khakhalin

    Full Text Available In the developing mammalian brain, gamma-aminobutyric acid (GABA is thought to play an excitatory rather than an inhibitory role due to high levels of intracellular Cl(- in immature neurons. This idea, however, has been questioned by recent studies which suggest that glucose-based artificial cerebrospinal fluid (ACSF may be inadequate for experiments on immature and developing brains. These studies suggest that immature neurons may require alternative energy sources, such as lactate or pyruvate. Lack of these other energy sources is thought to result in artificially high intracellular Cl(- concentrations, and therefore a more depolarized GABA receptor (GABAR reversal potential. Since glucose metabolism can vary widely among different species, it is important to test the effects of these alternative energy sources on different experimental preparations. We tested whether pyruvate affects GABAergic transmission in isolated brains of developing wild type Xenopus tadpoles in vitro by recording the responsiveness of tectal neurons to optic nerve stimulation, and by measuring currents evoked by local GABA application in a gramicidin perforated patch configuration. We found that, in contrast with previously reported results, the reversal potential for GABAR-mediated currents does not change significantly between developmental stages 45 and 49. Partial substitution of glucose by pyruvate had only minor effects on both the GABA reversal potential, and the responsiveness of tectal neurons at stages 45 and 49. Total depletion of energy sources from the ACSF did not affect neural responsiveness. We also report a strong spatial gradient in GABA reversal potential, with immature cells adjacent to the lateral and caudal proliferative zones having more positive reversal potentials. We conclude that in this experimental preparation standard glucose-based ACSF is an appropriate extracellular media for in vitro experiments.

  4. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique

    Science.gov (United States)

    van Onna, M; Ten Cate, D F; Tsoi, K L; Meier, A J L; Jacobs, J W G; Westgeest, A A A; Meijer, P B L; van Beek, M C; Rensen, W H J; Bijlsma, J W J

    2016-01-01

    Objectives In rheumatoid arthritis (RA), treat-to-target strategies require instruments for valid detection of joint inflammation. Therefore, imaging modalities are increasingly used in clinical practice. Optical spectral transmission (OST) measurements are non-invasive and fast and may therefore have benefits over existing imaging modalities. We tested whether OST could measure disease activity validly in patients with RA. Methods In 59 patients with RA and 10 patients with arthralgia, OST, joint counts, Disease Activity Score (DAS) 28 and ultrasonography (US) were performed. Additionally, MRI was performed in patients with DAS28<2.6. We developed and validated within the same cohort an algorithm for detection of joint inflammation by OST with US as reference. Results At the joint level, OST and US performed similarly inproximal interphalangeal-joints (area under the receiver-operating curve (AUC) of 0.79, p<0.0001) andmetacarpophalangeal joints (AUC 0.78, p<0.0001). Performance was less similar in wrists (AUC 0.62, p=0.006). On the patient level, OST correlated moderately with clinical examination (DAS28 r=0.42, p=0.001), and US scores (r=0.64, p<0.0001). Furthermore, in patients with subclinical and low disease activity, there was a correlation between OST and MRI synovitis score (RAMRIS (Rheumatoid Arthritis MRI Scoring) synovitis), r=0.52, p=0.005. Conclusions In this pilot study, OST performed moderately in the detection of joint inflammation in patients with RA. Further studies are needed to determine the diagnostic performance in a new cohort of patients with RA. PMID:26452538

  5. A downstream transmission scheme of optical burst switching in ethernet passive optical networks with burst access mode%支持突发接入模式EPON下行传输方案

    Institute of Scientific and Technical Information of China (English)

    陈希; 范红

    2012-01-01

    分析了支持突发接入模式的EPON在下行传输中业务流特性的变化问题,提出了在下行传输时OLT向ONU分解转发帧的传输方案.通过对下行带宽资源实行基于优先级的调度,减少因数据帧到达的突发性对某些高优先级的数据帧的影响;利用滑动窗控制每个ONU的数据帧到达速率,解决大量数据帧到达造成ONU处理负荷过重的问题.利用OPNET Modeler仿真平台建立网络模型并进行仿真,验证了方案的可行性.%The data flow characteristics in downstream transmission of Ethernet Passive Optical Network (EPON) , which is integrated with burst access mode,are analyzed in this paper,and a downstream transmission scheme based on optical burst switching is proposed hereby. The bursting arrival of data frames from Optical Line Terminal (OLT) will fully occupy the downlink bandwidth, thus delay the transmission of data frame with higher priority, and overload the Optical Network Unit (ONU). The influences of burst arriving data frames on the transmission of higher-priority data frames can he, reduced through scheduling the downlink bandwidth resources based on priority. The sliding windows are used to regulate the arrival rate of each ONU data frame to relieve the overload of ONU processing. The transmission scheme is simulated and evaluated on OPNET Modeler. The results verify the feasibility of the scheme.

  6. Hubble Space Telescope Transmission Spectroscopy of the Exoplanet HD 189733b: High-altitude atmospheric haze in the optical and near-UV with STIS

    CERN Document Server

    Sing, D K; Aigrain, S; Charbonneau, D; Desert, J -M; Gibson, N; Gilliland, R; Hayek, W; Henry, G; Knutson, H; Etangs, A Lecavelier des; Mazeh, T; Tal-Or, L

    2011-01-01

    We present Hubble Space Telescope optical and near-ultraviolet transmission spectra of the transiting hot-Jupiter HD189733b, taken with the repaired Space Telescope Imaging Spectrograph (STIS) instrument. The resulting spectra cover the range 2900-5700 Ang and reach per-exposure signal-to-noise levels greater than 11,000 within a 500 Ang bandwidth. We used time series spectra obtained during two transit events to determine the wavelength dependance of the planetary radius and measure the exoplanet's atmospheric transmission spectrum for the first time over this wavelength range. Our measurements, in conjunction with existing HST spectra, now provides a broadband transmission spectrum covering the full optical regime. We find a planetary transmission spectrum in good agreement with that of Rayleigh scattering from a high-altitude atmospheric haze as previously found from HST ACS camera. The STIS data also shows unambiguous evidence of a large occulted stellar spot during one of our transit events, which we use...

  7. 基于业务的光接入网路由选择算法%Algorithm of optical access network routing selection based on transmission business

    Institute of Scientific and Technical Information of China (English)

    孙立炜; 林峰

    2012-01-01

    Unlike optical backbone network, optical access network has its own characteristics and routing algorithms. An optical access network routing algorithm based on transmission business is proposed. Weighted graph model and sub-algorithm are made according to the style and importance of transmission business, by which the network resources is deployed appropriately. The results of engineering application demonstrate that the algorithm can enhance transmission quality.%光接入网有着不同于光骨干网的特点和问题,不能直接套用光骨干网的路由选择算法.提出了一种基于业务的光接入网的路由选择算法.其思想是根据业务类型和重要性构建不同的带权图模型,每一种模型采用相应的子算法,使整体资源得到合理配置.实践证明,该算法能够改善网络的传输质量.

  8. Study on the optical transmission characteristics of Cassegrain antenna%卡塞格伦天线光传输特性研究

    Institute of Scientific and Technical Information of China (English)

    孙全国

    2015-01-01

    In this paper,the transmission theory of Casey Glenn optical antenna system are analyzed,the transmission properties of Casey Glenn optical antenna on the basis of the simulation analysis,through the experiment discovered that the transmission efficiency and lotus root axis deviation will directly affect the Casey Glenn antenna efficiency,we expect this research can provide feasible ideas and methods for research of Casey Glenn optics antenna characteristics problems.%本文对卡塞格伦光学天线系统的传输理论进行了分析,在此基础上对卡塞格伦光学天线的传输特性进行了仿真实验分析,通过实验发现偏轴将直接影响卡塞格伦天线的传输效率和藕合效率,期望本文的研究能够为卡塞格伦光学天线特性问题的研究提供可行的思路和方法。

  9. Determination of the sputter rate variation pattern of a silicon carbide target for radio frequency magnetron sputtering using optical transmission measurements

    Energy Technology Data Exchange (ETDEWEB)

    Galvez de la Puente, G. [Departamento de Ciencias, Seccion Fisica, Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, Apartado Postal 1761, Lima 32 (Peru); Department of Materials Science 6, University of Erlangen, Martensstrasse 7, 91058-Erlangen (Germany); Guerra Torres, J.A. [Departamento de Ciencias, Seccion Fisica, Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, Apartado Postal 1761, Lima 32 (Peru); Erlenbach, O. [Departamento de Ciencias, Seccion Fisica, Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, Apartado Postal 1761, Lima 32 (Peru); Department of Materials Science 6, University of Erlangen, Martensstrasse 7, 91058-Erlangen (Germany); Steidl, M. [Department of Materials Science 6, University of Erlangen, Martensstrasse 7, 91058-Erlangen (Germany); Weingaertner, R., E-mail: rolandw@fisica.pucp.edu.pe [Departamento de Ciencias, Seccion Fisica, Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, Apartado Postal 1761, Lima 32 (Peru); Department of Materials Science 6, University of Erlangen, Martensstrasse 7, 91058-Erlangen (Germany); De Zela, F. [Departamento de Ciencias, Seccion Fisica, Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, Apartado Postal 1761, Lima 32 (Peru); Winnacker, A. [Department of Materials Science 6, University of Erlangen, Martensstrasse 7, 91058-Erlangen (Germany)

    2010-10-25

    We produce amorphous silicon carbide thin films (a-SiC) by radio frequency (rf) magnetron sputtering from SiC bulk target. We present the emission pattern of the rf magnetron with SiC target as a function of process parameters, like target sample distance, rf power, sputtering rate and process gas pressure. The emission pattern is determined by means of thickness distribution of the deposited a-SiC films obtained from optical transmission measurements using a slightly improved method of Swanepoel concerning the determination of construction of the envelopes in the interference pattern of the transmission spectra. A calibration curve is presented which allows the conversion of integrated transmission to film thickness. Holding constant a set of process parameters and only varying the target sample distance the emission pattern of the rf magnetron with SiC target was determined, which allowed us to predict the deposition rate distribution for a wide range of process parameters and target geometry. In addition, we have found that the transmission spectra of the a-SiC films change with time and saturate after approximately 10 days. Within this process no change in thickness is involved, so that the determination of thickness using transmission data is justified.

  10. Design and performance evaluation of an OpenFlow-based control plane for software-defined elastic optical networks with direct-detection optical OFDM (DDO-OFDM) transmission.

    Science.gov (United States)

    Liu, Lei; Peng, Wei-Ren; Casellas, Ramon; Tsuritani, Takehiro; Morita, Itsuro; Martínez, Ricardo; Muñoz, Raül; Yoo, S J B

    2014-01-13

    Optical Orthogonal Frequency Division Multiplexing (O-OFDM), which transmits high speed optical signals using multiple spectrally overlapped lower-speed subcarriers, is a promising candidate for supporting future elastic optical networks. In contrast to previous works which focus on Coherent Optical OFDM (CO-OFDM), in this paper, we consider the direct-detection optical OFDM (DDO-OFDM) as the transport technique, which leads to simpler hardware and software realizations, potentially offering a low-cost solution for elastic optical networks, especially in metro networks, and short or medium distance core networks. Based on this network scenario, we design and deploy a software-defined networking (SDN) control plane enabled by extending OpenFlow, detailing the network architecture, the routing and spectrum assignment algorithm, OpenFlow protocol extensions and the experimental validation. To the best of our knowledge, it is the first time that an OpenFlow-based control plane is reported and its performance is quantitatively measured in an elastic optical network with DDO-OFDM transmission.

  11. Implementation of orthogonal frequency division multiplexing (OFDM) and advanced signal processing for elastic optical networking in accordance with networking and transmission constraints

    Science.gov (United States)

    Johnson, Stanley

    An increasing adoption of digital signal processing (DSP) in optical fiber telecommunication has brought to the fore several interesting DSP enabled modulation formats. One such format is orthogonal frequency division multiplexing (OFDM), which has seen great success in wireless and wired RF applications, and is being actively investigated by several research groups for use in optical fiber telecom. In this dissertation, I present three implementations of OFDM for elastic optical networking and distributed network control. The first is a field programmable gate array (FPGA) based real-time implementation of a version of OFDM conventionally known as intensity modulation and direct detection (IMDD) OFDM. I experimentally demonstrate the ability of this transmission system to dynamically adjust bandwidth and modulation format to meet networking constraints in an automated manner. To the best of my knowledge, this is the first real-time software defined networking (SDN) based control of an OFDM system. In the second OFDM implementation, I experimentally demonstrate a novel OFDM transmission scheme that supports both direct detection and coherent detection receivers simultaneously using the same OFDM transmitter. This interchangeable receiver solution enables a trade-off between bit rate and equipment cost in network deployment and upgrades. I show that the proposed transmission scheme can provide a receiver sensitivity improvement of up to 1.73 dB as compared to IMDD OFDM. I also present two novel polarization analyzer based detection schemes, and study their performance using experiment and simulation. In the third implementation, I present an OFDM pilot-tone based scheme for distributed network control. The first instance of an SDN-based OFDM elastic optical network with pilot-tone assisted distributed control is demonstrated. An improvement in spectral efficiency and a fast reconfiguration time of 30 ms have been achieved in this experiment. Finally, I

  12. THE OPTICAL AND NEAR-INFRARED TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ 1214b: FURTHER EVIDENCE FOR A METAL-RICH ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Bean, Jacob L.; Desert, Jean-Michel; Stalder, Brian; Berta, Zachory K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kabath, Petr [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago (Chile); Seager, Sara [Department of Earth, Atmospheric, and Planetary Sciences and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Miller-Ricci Kempton, Eliza [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Homeier, Derek [Centre de Recherche Astrophysique de Lyon, UMR 5574, CNRS, Universite de Lyon, Ecole Normale Superieure de Lyon, 46 Allee d' Italie, F-69364 Lyon Cedex 07 (France); Walsh, Shane [Australian Astronomical Observatory and Curtin Institute of Radio Astronomy, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Seifahrt, Andreas, E-mail: jbean@cfa.harvard.edu [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States)

    2011-12-10

    We present an investigation of the transmission spectrum of the 6.5 M{sub Circled-Plus} planet GJ 1214b based on new ground-based observations of transits of the planet in the optical and near-infrared, and on previously published data. Observations with the VLT + FORS and Magellan + MMIRS using the technique of multi-object spectroscopy with wide slits yielded new measurements of the planet's transmission spectrum from 0.61 to 0.85 {mu}m, and in the J, H, and K atmospheric windows. We also present a new measurement based on narrow-band photometry centered at 2.09 {mu}m with the VLT + HAWKI. We combined these data with results from a reanalysis of previously published FORS data from 0.78 to 1.00 {mu}m using an improved data reduction algorithm, and previously reported values based on Spitzer data at 3.6 and 4.5 {mu}m. All of the data are consistent with a featureless transmission spectrum for the planet. Our K-band data are inconsistent with the detection of spectral features at these wavelengths reported by Croll and collaborators at the level of 4.1{sigma}. The planet's atmosphere must either have at least 70% H{sub 2}O by mass or optically thick high-altitude clouds or haze to be consistent with the data.

  13. Controllable transmission photonic band gap and all-optical switching behaviors of 1-D InAs/GaAs quantum-dot photonic crystal

    Science.gov (United States)

    Hu, Zhenhua; Xiang, Bowen; Xing, Yunsheng

    2016-12-01

    Transmission optical properties of one-dimensional (1-D) InAs/GaAs quantum-dot photonic crystal (QD-PC), composed of 400 elementary cells, were analyzed by using transfer matrix method. In our calculations, a homogeneous broadening with temperature and other inhomogeneous broadening with quantum dot (QD) size fluctuations are introduced. Our results show that a large optical Stark shift occurs at the high energy edge of the transmission photonic band-gap (TPBG) when, which exhibits the function of light with light, an external laser field acts resonantly on the excitons in the InAs QDs. Utilized this TPBG based on the pump-probe geometry, an all-optical switch can be constructed and the on-off switching extinction ratio (SER) is varied with both the temperature and the inhomogeneity of QDs. Significantly, it still maintains switching behavior and can process the data sequence of return-to-zero codes of 250 Gb/s even if the QD standard deviation of relative size fluctuations (SD-RSF) is up to 3% and the temperature is at 100 K.

  14. 支撑光网络与无线网络融合的传输技术%Transmission Technology for Integration of Optical and Wireless Network

    Institute of Scientific and Technical Information of China (English)

    刘琪; 胡晶晶

    2013-01-01

    This paper studies the transmission characteristics of communication system based on Radio over Fiber(ROF) technology,and then studies the application of ROF technology in access network for realization of optical and wireless convergence,which provides one of the most promising solutions for 'last mile' access network.By analyzing integrated optical and wireless network architecture,the paper will discuss the key technologies involved in the network integration and focus on the investigation of transmission characteristics of the ROF technology in communication systems.Results show that the error vector magnitude (EVM) of the demodulated signal is 8.87% after 10.36 km optical fiber transmission and still remains almost as good performance as the original signal,which indicates that both the single sideband filtering transmission scheme and the carrier suppression transmission scheme used in the paper can effectively combat the influence of dispersion induced power fading and achieve long-distance transmission of the signal.With optimized transmission scheme,the optical and wireless access network based on ROF technology can realize long distance transmission of signal without influercing the signal quality.%目的 研究基于射频光纤传输(Radio Over Fiber,ROF)技术的通信系统传输特性及ROF技术在光与无线网络融合的接入网中的应用,为“最后一公里”的接入网提供理想的解决方案.方法 分析光与无线网络融合的网络构架,对网络融合中的关键技术进行对比分析,对基于ROF技术的通信系统的传输特性进行实验研究,通过星座图观察解调的QPSK信号.结果 采用单边带滤波的传输方案以及载波抑制的传输方案,经过10.36km光纤传输之后,所得到解调信号的矢量信号误差向量幅度(Error Vector Magnitude,EVM)值为8.87%,基本保持了原始信号的性能,可有效对抗色散引入的功率衰减,实现长距离的信号传输.结论 通过选择

  15. Fast-synchronization and low-timing-jitter self-clocking concept for 160 Gbit/s optical time-division multiplexing transmissions.

    Science.gov (United States)

    Zhang, Shangjian; Gomez-Agis, Fausto; Liu, Yong; Calabretta, Nicola; Tangdiongga, Eduward; Dorren, Harm J S

    2010-01-01

    We propose a self-clocking method based on in-band clock pilot insertion at the transmission data signal. The method can achieve clock recovery without the need for an ultrafast phase comparator and a phase-locked loop in the receiver. We demonstrate fast synchronization, low timing jitter, and a highly stable recovered clock from a 160 Gbit/s optical time-division multiplexing data signal after a 51 km fiber transmission. The recovered clock shows no patterning effect with a clock dynamic range of 10 dB for error-free operation of 160 to 40 Gbit/s demultiplexing with a power penalty of 1.1 dB.

  16. 8×40 Gb/s 55-km WDM transmission over conventional fiber using a new RZ optical source

    DEFF Research Database (Denmark)

    Yu, Jianjun; Zheng, Xueyan; Liu, Fenghai;

    2000-01-01

    A multiwavelength RZ optical source with equal amplitudes and pulsewidths is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of a common dispersion shifted fiber. The converted wavelengths of the eight signal pulses are in agreement with the ITU...

  17. PMD and chromatic dispersion compensation in a 1.76-terabit/s (44 x 43 Gbit/s) optical transmission experiment over 600-km SMF

    Science.gov (United States)

    Rasmussen, Jens C.

    2004-10-01

    A simple, adaptive PMD compensator is demonstrated in a 1.76Terabit/s (44 x 43 Gbit/s) transmission experi- ment over 600km SMF with a mean PMD of 8 ps. The PMDC is composed of a LiNbO3 polarization-controller followed by a component with an adjustable differential group delay (DGD) in the range of 0-20 ps. Feedback control is provided by means of continuously monitoring and maximizing the degree of polarization (DOP). This PMDC is shown to automatically compensate well for 1st-order (0-28 ps) and one part - the depolarization - of 2nd-order (0-130 ps2) PMD. Polarization dependent chromatic dispersion (PCD), being the other part of 2nd-order PMD, is negligible as long transmission systems without a PMDC are considered. But in fact PCD plays a role when an optical PMDC is introduced. Because of the anyway tight tolerance of 40 Gbit/s optical signals to chromatic dispersion, the variable dispersion compensator VIPA (virtually imaged phased array) with a tuning range of +/-800 ps/nm is introduced besides the PMDC. Therefore, with VIPA not only residual chro- matic dispersion put also PCD is e«ectively compensated for. Using adaptive optical technologies compensating for PMD and chromatic dispersion, error-free transmission (BER< 10í15 with FEC, Q-margin=3 dB) of 44 x 43 Gbit/s (1.76 Tbit/s) over 600km of high PMD (8 ps) SMF is demonstrated.

  18. Low complexity Reed-Solomon-based low-density parity-check design for software defined optical transmission system based on adaptive puncturing decoding algorithm

    Science.gov (United States)

    Pan, Xiaolong; Liu, Bo; Zheng, Jianglong; Tian, Qinghua

    2016-08-01

    We propose and demonstrate a low complexity Reed-Solomon-based low-density parity-check (RS-LDPC) code with adaptive puncturing decoding algorithm for elastic optical transmission system. Partial received codes and the relevant column in parity-check matrix can be punctured to reduce the calculation complexity by adaptive parity-check matrix during decoding process. The results show that the complexity of the proposed decoding algorithm is reduced by 30% compared with the regular RS-LDPC system. The optimized code rate of the RS-LDPC code can be obtained after five times iteration.

  19. Optical transmission damage of undoped and Ce doped Y3Al5O12 scintillation crystals under 24 GeV protons high fluence

    Science.gov (United States)

    Auffray, E.; Fedorov, A.; Dormenev, V.; Houžvička, J.; Korjik, M.; Lucchini, M. T.; Mechinsky, V.; Ochesanu, S.

    2017-06-01

    This report presents results on the optical transmission damage of undoped and Ce doped Y3Al5O12 scintillation crystals under high fluence of 24 GeV protons. We observed that, similarly to other middle heavy scintillators, it possesses the unique radiation hardness at fluence values as high as 5×1014 p/cm2 and it is thus promising for the application in the detectors at High Luminosity LHC. The crystalline structure of the garnet scintillator allows to control and further optimize its scintillation parameters, such as scintillation decay time and emission wavelength, and shows a limited set of the radioisotopes after the irradiation with protons.

  20. 4.8 Gbit/s 16-QAM-OFDM transmission based on compact 450-nm laser for underwater wireless optical communication

    KAUST Repository

    Oubei, Hassan M.

    2015-08-26

    We experimentally demonstrate an underwater wireless optical communications (UWOC) employing 450-nm TO-9 packaged and fiberpigtailed laser diode (LD) directly encoded with an orthogonal frequency division multiplexed quadrature amplitude modulation (QAM-OFDM) data. A record data rate of up to 4.8 Gbit/s over 5.4-m transmission distance is achieved. By encoding the full 1.2-GHz bandwidth of the 450-nm LD with a 16-QAM-OFDM data, an error vector magnitude (EVM) of 16.5%, a signal-to-noise ratio (SNR) of 15.63 dB and a bit error rate (BER) of 2.6 × 10-3, well pass the forward error correction (FEC) criterion, were obtained. © 2015 Optical Society of America.

  1. Colorless WDM-PON based on a Fabry-Pérot laser diode and reflective semiconductor optical amplifiers for simultaneous transmission of bidirectional gigabit baseband signals and broadcasting signal.

    Science.gov (United States)

    Pham, Thang Tien; Kim, Hyun-Seung; Won, Yong-Yuk; Han, Sang-Kook

    2009-09-14

    A novel WDM-PON system delivering bidirectional baseband data and broadcasting data is proposed and demonstrated. A subcarrier multiplexing signal is broadcasted to all users by modulating a broadband optical source based on a Fabry-Pérot laser diode. Reflective semiconductor optical amplifiers are used as colorless modulators for the baseband data at both optical line terminal and remote optical network units. Transmission performance including bit error rate of bidirectional gigabit data and error vector magnitude of broadcasting data of many optical channels is investigated. Additionally, the data rate for the broadcasting signal was improved by using an external modulator.

  2. Application of Modern Optical Fiber Communication Transmission Technology%现代光纤通信传输技术的应用探讨

    Institute of Scientific and Technical Information of China (English)

    李彬; 赵静娟

    2013-01-01

    Optical fiber communication, as the principal communication technology in modern telecom network, has achieved rapid development and fairly good economic benefit in recent years. Along with the continuous development of communication technology, the optical fiber-leading communication transmission technology, for its large capacity, high speed and strong anti-interference capability, is widely applied in the field of communication. This paper describes the characteristics of optical fiber communication, discusses the concrete application and the future development trend of modern optical fiber communication transmission technology.%  在现代电信网中有着重要地位的光纤通信已经成为主要的通信技术,并在近几年发展速度非常快,也取得了良好的效益。随着通信技术的不断发展,以光纤为主导的通信传输技术由于其传输信息量大、速递快、抗干扰能力强等特点在通信领域得到了广泛的应用。这里介绍了光纤通信的特点,探讨了现代光纤通信传输技术的具体应用以及未来的发展趋势,随着对信息量需求的增加,光纤通信一定会取代其他的通信方式,成为信息通信领域中主流的技术。

  3. Secure transmission of static and dynamic images via chaotic encryption in acousto-optic hybrid feedback with profiled light beams

    Science.gov (United States)

    Chatterjee, Monish R.; Almehmadi, Fares S.

    2015-01-01

    Secure information encryption via acousto-optic (AO) chaos with profiled optical beams indicates substantially better performance in terms of system robustness. This paper examines encryption of static and time-varying (video) images onto AO chaotic carriers using Gaussian-profile beams with diffracted data numerically generated using transfer functions. The use of profiled beams leads to considerable improvement in the encrypted signal. While static image encryption exhibits parameter tolerances within about +/-10% for uniform optical beams, profiled beams reduce the tolerance to less than 1%, thereby vastly improving both the overall security of the transmitted information as well as the quality of the image retrieval.

  4. Modal dispersion, pulse broadening and maximum transmission rate in GRIN optical fibers encompass a central dip in the core index profile

    Science.gov (United States)

    El-Diasty, Fouad; El-Hennawi, H. A.; El-Ghandoor, H.; Soliman, Mona A.

    2013-12-01

    Intermodal and intramodal dispersions signify one of the problems in graded-index multi-mode optical fibers (GRIN) used for LAN communication systems and for sensing applications. A central index dip (depression) in the profile of core refractive-index may occur due to the CVD fabrication processes. The index dip may also be intentionally designed to broaden the fundamental mode field profile toward a plateau-like distribution, which have advantages for fiber-source connections, fiber amplifiers and self-imaging applications. Effect of core central index dip on the propagation parameters of GRIN fiber, such as intermodal dispersion, intramodal dispersion and root-mean-square broadening, is investigated. The conventional methods usually study optical signal propagation in optical fiber in terms of mode characteristics and the number of modes, but in this work multiple-beam Fizeau interferometry is proposed as an inductive but alternative methodology to afford a radial approach to determine dispersion, pulse broadening and maximum transmission rate in GRIN optical fiber having a central index dip.

  5. Determination of the optical parameters of a-Si:H thin films deposited by hot wire–chemical vapour deposition technique using transmission spectrum only

    Indian Academy of Sciences (India)

    Nabeel A Bakr; A M Funde; V S Waman; M M Kamble; R R Hawaldar; D P Amalnerkar; S W Gosavi; S R Jadkar

    2011-03-01

    Three demonstration samples of intrinsic hydrogenated amorphous silicon (a-Si:H) films were deposited using hot wire–chemical vapour deposition (HW–CVD) technique. The optical parameters and the thickness were determined from the extremes of the interference fringes of transmission spectrum in the range of 400–2500 nm using the envelope method. The calculated values of the refractive index () were fitted using the two-term Cauchy dispersion relation and the static refractive index values (0) obtained were 2.799, 2.629 and 3.043 which were in the range of the reported values. The calculated thicknesses for all samples were cross-checked with Taly-Step profilometer and found to be almost equal. Detailed analysis was carried out to obtain the optical band gap (g) using Tauc’s method and the estimated values were 1.99, 2.01 and 1.75 eV. The optical band gap values were correlated with the hydrogen content (H) in the samples calculated from Fourier transform infrared (FTIR) analysis. An attempt was made to apply Wemple–DiDomenico single-effective oscillator model to the a-Si:H samples to calculate the optical parameters. The optical band gap obtained by Tauc’s method and the static refractive index calculated from Cauchy fitting are in good agreement with those obtained by the single-effective oscillator model. The real and the imaginary parts of dielectric constant (r, ), and the optical conductivity () were also calculated.

  6. Perspectives of Long-Haul WDM Transmission Systems Based on Phase-Insensitive Fiber-Optic Parametric Amplifiers

    DEFF Research Database (Denmark)

    Jazayerifar, M.; Sackey, I.; Elschner, R.

    2015-01-01

    The deployment of phase-insensitive fiber-opticparametric amplifiers (PI-FOPAs) as inline amplifiers in longhaul WDM transmission systems is discussed, and it is outlined how to design PI-FOPAs to be a valuable upgrade option for this application....

  7. Regaining the FORS: making optical ground-based transmission spectroscopy of exoplanets with VLT+FORS2 possible again

    CERN Document Server

    Boffin, Henri M J; Blanchard, Guillaume; Gonzalez, Oscar; Moehler, Sabine; Gibson, Neale; Ancker, Mario van den; Smoker, Jonathan; Anderson, Joseph; Hummel, Christian; Dobrzycka, Danuta; Smette, Alain; Rupprecht, Gero

    2016-01-01

    Transmission spectroscopy facilitates the detection of molecules and/or clouds in the atmospheres of exoplanets. Such studies rely heavily on space-based or large ground-based observatories, as one needs to perform time- resolved, high signal-to-noise spectroscopy. The FORS2 instrument at ESO's Very Large Telescope is the obvious choice for performing such studies, and was indeed pioneering the field in 2010. After that, however, it was shown to suffer from systematic errors caused by the Longitudinal Atmospheric Dispersion Corrector (LADC). This was successfully addressed, leading to a renewed interest for this instrument as shown by the number of proposals submitted to perform transmission spectroscopy of exoplanets. We present here the context, the problem and how we solved it, as well as the recent results obtained. We finish by providing tips for an optimum strategy to do transmission spectroscopy with FORS2, in the hope that FORS2 may become the instrument of choice for ground-based transmission spectro...

  8. Transmission Enhancement of High-$k$ Waves through Metal-InGaAsP Multilayers Calculated via Scattering Matrix Method with Semi-Classical Optical Gain

    CERN Document Server

    Smalley, Joseph S T; Shahin, Shiva; Kanté, Boubacar; Fainman, Yeshaiahu

    2015-01-01

    We analyze the steady-state transmission of high-momentum (high-$k$) electromagnetic waves through metal-semiconductor multilayer systems with loss and gain in the near-infrared (NIR). Using a semi-classical optical gain model in conjunction with the scattering matrix method (SMM), we study indium gallium arsenide phosphide (InGaAsP) quantum wells as the active semiconductor, in combination with the metals, aluminum-doped zinc oxide (AZO) and silver (Ag). Under moderate external pumping levels, we find that NIR transmission through Ag/InGaAsP systems may be enhanced by several orders of magnitude relative to the unpumped case, over a large angular and frequency bandwidth. Conversely, transmission enhancement through AZO/InGaAsP systems is orders of magnitude smaller, and has a strong frequency dependence. We discuss the relative importance of Purcell enhancement on our results and validate analytical calculations based on the SMM with numerical finite-difference time domain simulations.

  9. Transmission electron microscopy and time resolved optical spectroscopy study of the electronic and structural interactions of ZnO nanorods with bovine serum albumin.

    Science.gov (United States)

    Klaumünzer, M; Weichsel, U; Mačković, M; Spiecker, E; Peukert, W; Kryschi, C

    2013-08-22

    The adsorption behavior and electronic interactions of bovine serum albumin (BSA) with ZnO nanorod surfaces were investigated using high-resolution transmission electron microscopy as well as stationary and time-resolved optical spectroscopy techniques. Transmission electron microscopy shows that ZnO nanorod surfaces are surrounded by a homogeneous amorphous BSA film with thicknesses between ~2.5 and 5.0 nm. The electronic structure and adsorption geometry of BSA were examined using high-angle annular dark field scanning transmission electron microscopy combined with electron energy loss spectroscopy. The adsorption process was observed to result into an unfolded conformation of BSA becoming predominantly bound in the side-on orientation at the ZnO surface. This adsorption mode of the BSA molecules allows for a strong interaction with surface states of the ZnO nanorods. This is obvious from its efficient quenching of the defect-center photoluminescence of ZnO. Complementary information of electronic interactions across the ZnO nanorod interface was obtained from femtosecond transient absorption spectroscopy experiments. The rise dynamics of the measured transients revealed altered hole trapping dynamics and, thus, indicated to heterogeneous charge transfer as emerging from adsorbed BSA molecules to defect centers of the ZnO interface.

  10. New Method For Modeling and Design Optical SDM Transmission System Using Long Haul FMF with PDM/DWDM Techniques Enabling QPSK Modulation Format

    Directory of Open Access Journals (Sweden)

    Ibrahim Abdullah

    2017-07-01

    Full Text Available This paper presents the modeling and design of ultra high capacity Space Division Multiplexing (SDM transmission system. Polarization Division Multiplexing (PDM and Dense Wavelength Division Multiplexing (DWDM techniques are also proposed in this system to increase total system data rate. For the ultra-high capacity need of SDM, Few Mode Fiber (FMF was proposed as SDM best technology for obtaining ultra-high bit rates with long haul transmission. The description and design of 8-DWDM channels over 7 modes SDM/PDM system was explored as future of ultra-high capacity optical network. A long-haul transmission of 1080 Km recorded for 8-WDM channels-7modes-SDM/PDM system by using QPSK modulation format. The total bit rate achieved by our designed system is 4.48 Tb/s at 40Gb/s. Channel estimation techniques were proposed to enable the transmitter pre-shaping design for the linear effects mitigation by using different DSP algorithms. The presence of linear and nonlinear losses limits the acceptable range of input power that produce the required BER for our proposed system from -4dBm to 4dBm.

  11. Optical 16-QAM-52-OFDM transmission at 4 Gbit/s by directly modulating a coherently injection-locked colorless laser diode.

    Science.gov (United States)

    Chi, Yu-Chieh; Li, Yi-Cheng; Wang, Huai-Yung; Peng, Peng-Chun; Lu, Hai-Han; Lin, Gong-Ru

    2012-08-27

    Coherently injection-locked and directly modulated weak-resonant-cavity laser diode (WRC-FPLD) for back-to-back optical 16-quadrature-amplitude-modulation (QAM) and 52-subcarrier orthogonal frequency division multiplexing (OFDM) transmission with maximum bit rate up to 4 Gbit/s at carrier frequency of 2.5 GHz is demonstrated. The WRC-FPLD transmitter source is a specific design with very weak-resonant longitudinal modes to preserve its broadband gain spectral characteristics for serving as a colorless WDM-PON transmitter. Under coherent injection-locking, the relative-intensity noise (RIN) of the injection-locked WRC-FPLD can be suppressed to ?105 dBc/Hz and the error vector magnitude of the received optical OFDM data is greatly reduced with the amplitude error suppressed down 5.5%. Such a coherently injection-locked single-mode WRC-FPLD can perform both the back-to-back and the 25-km-SMF 16-QAM-52-OFDM transmissions with a symbol rate of 20-MSa/s in each OFDM subcarrier. After coherent injection locking, the BER of the back-to-back transmitted 16-QAM-52-OFDM data is reduced to 2.5 × 10(-5) at receiving power of ?10 dBm. After propagating along a 25-km-long SMF, a receiving power sensitivity of ?7.5 dBm is required to obtain a lowest BER of 2.5 × 10(-5), and a power penalty of 2.7 dB is observed when comparing with the back-to-back transmission.

  12. Dual-polarization multi-band optical OFDM transmission and transceiver limitations for up to 500 Gb/s uncompensated long-haul links.

    Science.gov (United States)

    Giacoumidis, E; Jarajreh, M A; Sygletos, S; Le, S T; Farjady, F; Tsokanos, A; Hamié, A; Pincemin, E; Jaouën, Y; Ellis, A D; Doran, N J

    2014-05-05

    A number of critical issues for dual-polarization single- and multi-band optical orthogonal-frequency division multiplexing (DP-SB/MB-OFDM) signals are analyzed in dispersion compensation fiber (DCF)-free long-haul links. For the first time, different DP crosstalk removal techniques are compared, the maximum transmission-reach is investigated, and the impact of subcarrier number and high-level modulation formats are explored thoroughly. It is shown, for a bit-error-rate (BER) of 10(-3), 2000 km of quaternary phase-shift keying (QPSK) DP-MB-OFDM transmission is feasible. At high launched optical powers (LOP), maximum-likelihood decoding can extend the LOP of 40 Gb/s QPSK DP-SB-OFDM at 2000 km by 1.5 dB compared to zero-forcing. For a 100 Gb/s DP-MB-OFDM system, a high number of subcarriers contribute to improved BER but at the cost of digital signal processing computational complexity, whilst by adapting the cyclic prefix length the BER can be improved for a low number of subcarriers. In addition, when 16-quadrature amplitude modulation (16QAM) is employed the digital-to-analogue/analogue-to-digital converter (DAC/ADC) bandwidth is relaxed with a degraded BER; while the 'circular' 8QAM is slightly superior to its 'rectangular' form. Finally, the transmission of wavelength-division multiplexing DP-MB-OFDM and single-carrier DP-QPSK is experimentally compared for up to 500 Gb/s showing great potential and similar performance at 1000 km DCF-free G.652 line.

  13. The Way of Reducing Current Values in Optical Ground Wires at Asymmetrical Faults on Overhead Transmission Lines

    Directory of Open Access Journals (Sweden)

    Egamnazarov Georgiy

    2016-12-01

    Full Text Available Given the fact that the installing costs of an optical ground wire on overhead lines directly depend on its cross-section, which in turn depends on the level of fault current it should withstand, in order to reduce these current values in the optical ground wire, I suggested performing its isolated descents from the end towers of the line with its transition to an optical cable. The research was carried out on the example of a 500 kV overhead line in the National Electric Power Grid. The Method of Symmetrical Components for calculating asymmetrical fault currents was not used; therefore, calculations were carried out on the base of presenting the line as a multi-wire system for the considered case as a five-wire system (optical ground wire, steel ground wire, and three phase wires. Such approach allows taking into account the initial asymmetry of the line parameters and modeling any kind of asymmetrical faults. The analyses of calculated results were performed. The conclusive evidence that the optical ground wire isolated descents from the end towers of the line give the possibility of reducing the level of maximal fault current distribution values in it and therefore its cross section, is presented.

  14. 基于光FFF的8×112 Gbit/s全光OFDM光纤传输系统%8× 112 Gbit/s all-optical OFDM fiber transmission system based on optical FFT

    Institute of Scientific and Technical Information of China (English)

    张洪波; 高翔; 张静; 邓明亮; 邱昆

    2013-01-01

    采用单个激光源,通过差分马赫-曾德尔(M-Z)外调制器产生8根等频率间隔为28 GHz的光频梳,每根光频梳彼此相干并作为光子载波,经112 Gb/s偏分复用(PDM)-正交相移键控(QPSK)信号调制后,波分复用后形成8路宽带的全光正交频分复用(OFDM)信号.接收端通过基于级联M-Z延时干涉仪(MZDI)的光学快速傅里叶变换(OFFT)实现全光OFDM信号的解复用.解复用后的每路信号经光采样后,采用与单载波PDM-QPSK系统中相同的数字相干解调进行数据恢复.提出的8×112 Gb/s全光OFDM系统在背靠背情况下,误码率(BER)为10-3时,光信噪比(OSNR)较单载波112 Gb/s PDM-QPSK系统多约9 dB.8×112 Gb/s全光OFDM信号经480 km光纤传输后,OSNR损伤约1.6 dB.仿真结果表明,全光OFDM系统的数字相干接收机可以较容易地实现对现有单载波系统扩容,并且不影响系统的传输性能.%As the 100 Gbit/s Ethernet (100 GbE) has gradually become a commercial reality, the next step of migration is toward 1 Tbit/s Ethernet transport. Coherent optical orthogonal frequency division multiplexing (CO-OFDM) has recently drawon much attention to improve system capacity and transmission distance over fiber for its superior performance in spectrum efficiency, robust chromatic dispersion (CD) tolerance, receiver sensitivity, and polarization mode diversity (PMD) resilience, which has also been considered as a promising candidate for long-haul transmissions. In conventional optical OFDM systems, analog-to-digital converter (ADC) and digital-to-analog converter (DAC) are needed at transmitter and receiver,respectively. However, the radio frequency (RF) bandwidths and sampling rates of ADC and DAC are limited by current manufacturing. To overcome this problem,an 8×112 Gbit/s all-optical OFDM transmission system is proposed in this paper. A single laser source is utilized to generate frequency comb source as the sub-carriers of the proposed all-optical OFDM

  15. Optical quantal analysis of synaptic transmission in wild-type and rab3-mutant Drosophila motor axons.

    Science.gov (United States)

    Peled, Einat S; Isacoff, Ehud Y

    2011-04-01

    Synaptic transmission from a neuron to its target cells occurs via neurotransmitter release from dozens to thousands of presynaptic release sites whose strength and plasticity can vary considerably. We report an in vivo imaging method that monitors real-time synaptic transmission simultaneously at many release sites with quantal resolution. We applied this method to the model glutamatergic system of the Drosophila melanogaster larval neuromuscular junction. We find that, under basal conditions, about half of release sites have a very low release probability, but these are interspersed with sites with as much as a 50-fold higher probability. Paired-pulse stimulation depresses high-probability sites, facilitates low-probability sites, and recruits previously silent sites. Mutation of the small GTPase Rab3 substantially increases release probability but still leaves about half of the sites silent. Our findings suggest that basal synaptic strength and short-term plasticity are regulated at the level of release probability at individual sites.

  16. Demonstration of 2×ONU 80 Gbps direct detection colorless polarization division multiplexing frequency division multiplexing passive optical network uplink transmission

    Science.gov (United States)

    Wang, Zhixin; Xu, Yinfan; Wang, Yanyi; Wang, Yuanquan; Chi, Nan

    2016-04-01

    In this study, we propose and experimentally demonstrate a simple direct detection passive optical network (PON) uplink transmission scheme based on frequency division multiplexing and polarization division multiplexing. Two optical network units (ONUs) are assigned to two different frequency bands at two different orthogonal polarization directions. At the optical line terminal, both ONU signals can be simultaneously detected by a single photodiode without utilizing any polarization control, polarization selection, or complicated polarization demultiplexing algorithms. As a proof-of-concept, the 2×ONU 80 Gbps 32-ary quadrature amplitude modulation Nyquist single carrier signals are successfully transmitted over 2 km standard single mode fiber or 20 km large effective area fiber with the assistance of frequency domain equalization and decision-directed least-mean-square. The measured bit error rate can be below the 7% pre-forward error correction threshold of 3.8×10-3. Meanwhile, this scheme is compatible with the widely used wavelength-division multiplexed PON, which shows the promising potential and feasibility of this proposal.

  17. Capacity-Approaching Modulation Formats for Optical Transmission Systems: Signal shaping and advanced de/muxing for efficient resource exploitation

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel

    Aiming for efficient fiber-optic data transport, this thesis addresses three scenario-specific modulation and/or multiplexing techniques which, leveraging digital signal processing, can further exploit the available resources.The considered environments are: (i) (ultra) long-haul networks, where ...

  18. MSDAR光纤传输与同步研究%Fibre-Optic Transmission and Synchronization of Multi-Station Digital Array Radar

    Institute of Scientific and Technical Information of China (English)

    龙伟军; 龚树凤; 贲德

    2013-01-01

    多基站数字阵雷达面临信号远距传输、时序同步与信号分集等技术难题.本文针对MSDAR构建了具有较强适用性的光纤同步系统.该系统采用信号分级同步策略对时序信号逐级同步,精度可达纳秒量级.采用多级复用技术显著提高单纤信道传输容量以解决MSDAR信号分集问题.本文分析了影响光纤传输同步性的诸方面因素,结合数字阵雷达原理建立了信号同步性对雷达性能影响的关系模型.详细分析了同步性对雷达波束指向影响.结果表明光纤同步系统若满足MSDAR系统需求,须折中考虑系统工作频率、带宽、通道等系统参数,定量的结果可由模型给出.%Multi-station digital array radar (MSDAR) confronts with several puzzles such as distant transmission,timing synchronization,signal distribution and collection.A universal fibre-optic transmission synchronization and signal diversity system is architected,which exploits hierarchical synchronization approaches to achieve precise synchronization of nanosecond magnitude.Hierarchical channel multiplex techniques are designed to promote the fibre-optic channel capacity to address the signal diversity difficulties of MSDAR.Based on the analysis of effects on synchronization and the characteristics of digital array radar (DAR),the mathematic models of the relationship between synchronization and radar performances are built.According to the models,the beam pointing errors are estimated.The theoretical analysis and simulation results indicate that the fibre-optic transmission synchronization system can satisfy high frequency MSDAR,but with the increase of operation frequency and bandwidth,the effects will be more serious and the quantitative results can be calculated on the models.

  19. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  20. Experimental verification of long-term evolution radio transmissions over dual-polarization combined fiber and free-space optics optical infrastructures.

    Science.gov (United States)

    Bohata, J; Zvanovec, S; Pesek, P; Korinek, T; Mansour Abadi, M; Ghassemlooy, Z

    2016-03-10

    This paper describes the experimental verification of the utilization of long-term evolution radio over fiber (RoF) and radio over free space optics (RoFSO) systems using dual-polarization signals for cloud radio access network applications determining the specific utilization limits. A number of free space optics configurations are proposed and investigated under different atmospheric turbulence regimes in order to recommend the best setup configuration. We show that the performance of the proposed link, based on the combination of RoF and RoFSO for 64 QAM at 2.6 GHz, is more affected by the turbulence based on the measured difference error vector magnitude value of 5.5%. It is further demonstrated the proposed systems can offer higher noise immunity under particular scenarios with the signal-to-noise ratio reliability limit of 5 dB in the radio frequency domain for RoF and 19.3 dB in the optical domain for a combination of RoF and RoFSO links.

  1. A 7-13 GHz low-noise tuned optical front-end amplifier for heterodyne transmission system application

    DEFF Research Database (Denmark)

    Ebskamp, Frank; Schiellerup, Gert; Høgdal, Morten

    1991-01-01

    The authors present a 7-13 GHz low-noise bandpass tuned optical front-end amplifier, showing 46±1 dBΩ transimpedance, and a noise spectral density of about 12 pA/√Hz. This is the first time such a flat response and such low noise were obtained simultaneously at these frequencies, without any furt......, resulting in a sensitivity of -41.7 dBm at a bit error rate of 10-9...

  2. Effect of complex optical field on the modulation instability of 100 km unrepeated fiber transmission system with DFRA

    Science.gov (United States)

    Yang, Yangyang; Xu, Pan; Hu, Zhengliang; Hu, Yongming

    2016-10-01

    With the development of networking technology and optical fiber sensor network technology, the use of optical fiber system to construct a large-scale, long distance optical fiber sensing network has become a hotspot of research. Optimizing the system to reach very long sensing ranges actually requires launching high pump and probe powers into the sensing fiber to provide a sufficient signal-to-noise ratio (SNR) on the measurements at the far end of the fiber. However, increasing the input power above a critical level excites undesired nonlinear effects such as the modulation instability (MI) and the stimulated Raman scattering (SRS), which deplete the pump and reduce the maximum sensing range of the system. Compared to SRS, MI shows a lower critical power and thus determines the maximum sensing range of a fiber sensor, so MI becomes the most important factor to limit the sensing range. In order to understand the MI in the system with the DFRA, we design a lot of experiments to test which factors will affect it in the system with distributed fiber Raman amplifier (DFRA) in this paper. From the threshold expression of MI and a lot of experiments, we found that the input power, the state of polarization, the phase and so on, have a significant impact on the system. According to the result of the experiments, we can find the Raman gain affects the MI and find some useful information for suppressing the MI in the later.

  3. Enhanced optical transmission through a star-shaped bull's eye at dual resonant-bands in UV and the visible spectral range.

    Science.gov (United States)

    Nazari, Tavakol; Khazaeinezhad, Reza; Jung, Woohyun; Joo, Boram; Kong, Byung-Joo; Oh, Kyunghwan

    2015-07-13

    Dual resonant bands in UV and the visible range were simultaneously observed in the enhanced optical transmission (EOT) through star-shaped plasmonic structures. EOTs through four types of polygonal bull's eyes with a star aperture surrounded by the concentric star grooves were analyzed and compared for 3, 4, 5, and 6 corners, using finite difference time domain (FDTD) method. In contrast to plasmonic resonances in the visible range, the UV-band resonance intensity was found to scale with the number of corners, which is related with higher order multipole interactions. Spectral positions and relative intensities of the dual resonances were analyzed parametrically to find optimal conditions to maximize EOT in UV-visible dual bands.

  4. Real-time optical OFDM transmissions with spectral efficiency up to 6.93 bit/s/Hz over 50 km SSMF IMDD systems

    Science.gov (United States)

    Zhang, Qianwu; Liu, Min; Chen, Jian; Dun, Han; Zhang, Junjie; Li, Yingchun; Song, Yingxiong; Wang, Min

    2017-03-01

    Real-time optical OFDM transmissions based on FPGA with 6.93 bit/s/Hz spectral efficiency by using simple directly modulated DFB laser and DAC/ADC with sampling rate as low as 2GS/s without inline amplifier are experimentally demonstrated. 7.09-Gb/s OFDM signals with subcarrier modulation format up to 512-QAM can be successfully transmitted over 50-km SSMF with adopted HD-FEC (3.8×10-3). The robustness of system performance is also extensively explored to determine the tolerance to DAC/ADC resolution mismatch. It is shown that aggregate system capacity can be maintained almost constant for DAC/ADC resolution mismatch as large as 3bits due to the utilization of adaptive bit and power loading scheme. On the other hand, for a certain system configuration and an expected signal line rate, it also gives a reference minimum DAC/ADC boundary for practical deployment.

  5. A search for TiO in the optical high-resolution transmission spectrum of HD 209458b: Hindrance due to inaccuracies in the line database

    CERN Document Server

    Hoeijmakers, H J; Snellen, I A G; Brogi, M; Birkby, J L; Schwarz, H

    2014-01-01

    The spectral signature of an exoplanet can be separated from the spectrum of its host star using high-resolution spectroscopy. During such observations, the radial component of the planet's orbital velocity changes, resulting in a significant Doppler shift which allows its spectral features to be extracted. Aims: In this work, we aim to detect TiO in the optical transmission spectrum of HD 209458b. Gaseous TiO has been suggested as the cause of the thermal inversion layer invoked to explain the dayside spectrum of this planet. Method: We used archival data from the 8.2m Subaru Telescope taken with the High Dispersion Spectrograph of a transit of HD209458b in 2002. We created model transmission spectra which include absorption by TiO, and cross-correlated them with the residual spectral data after removal of the dominating stellar absorption features. We subsequently co-added the correlation signal in time, taking into account the change in Doppler shift due to the orbit of the planet. Results: We detect no si...

  6. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  7. Efficient optical terahertz-transmission modulation in solution-processable organic semiconductor thin films on silicon substrate

    Science.gov (United States)

    Matsui, Tatsunosuke; Mori, Hiroki; Inose, Yuto; Kuromiya, Shota; Takano, Keisuke; Nakajima, Makoto; Hangyo, Masanori

    2016-03-01

    Terahertz (THz)-transmission modulation through the Si substrate coated with four π-conjugated materials under various laser light irradiation conditions was investigated using THz time-domain spectroscopy. Two of the π-conjugated low molecules, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), and two of the π-conjugated polymer materials, poly[5-(2-ethylhexyloxy)-2-methoxycyanoterephthalyliden] (MEH-CN-PPV) and poly(benzimidazobenzophenanthroline) (BBL), were investigated. Among these materials, PCBM and TIPS-pentacene showed higher modulation efficiencies and it was also shown that thermal annealing is quite effective in obtaining THz modulation efficiencies higher than those previously reported for copper phthalocyanine. Utilizing these solution-processable π-conjugated materials, various types of THz materials and devices could be fabricated by printing technologies. Our findings may open the way to fabricating various types of THz active devices.

  8. Nanometer scale correlation of optical and structural properties of individual InGaN/GaN nanorods by scanning transmission electron microscope cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Marcus; Schmidt, Gordon; Veit, Peter; Petzold, Silke; Bertram, Frank; Christen, Juergen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg (Germany); Albert, Steven; Bengoechea-Encabo, Ana Maria; Sanchez-Garcia, Miguel Angel; Calleja, Enrique [ISOM e Departamento de Ingenieria Electronica, Universidad Politecnica de Madrid (Spain)

    2013-07-01

    A potential benefit of nanorods as light emitters, aside from their very high crystal quality, relies on better light extraction efficiency as compared to thin films, because of the high surface to volume ratio. In this study we present a direct nano-scale correlation of the optical properties with the actual crystalline structure of ordered InGaN/GaN nanorods using low temperature cathodoluminescence spectroscopy in a scanning transmission electron microscope (STEM-CL). Direct comparison of the high-angle annular dark field image with the simultaneously recorded panchromatic CL mapping at 15 K reveals a weak luminescence from the bottom GaN layer. We observe the highest CL intensity in the middle of the InGaN region. The spectral position of the InGaN emission shifts continuously red from the GaN/InGaN interface (λ=409 nm) to the NR top (λ=446 nm) due to lattice pulling effects and InGaN partial decomposition. Additionally, optical active basal stacking faults in the GaN layer emitting at 366 nm can be found.

  9. Reversible NO2 Optical Fiber Chemical Sensor Based on LuPc2 Using Simultaneous Transmission of UV and Visible Light.

    Science.gov (United States)

    Bueno, Antonio; Lahem, Driss; Caucheteur, Christophe; Debliquy, Marc

    2015-04-27

    In this paper, an NO2 optical fiber sensor is presented for pollution monitoring in road traffic applications. This sensor exploits the simultaneous transmission of visible light, as a measurement signal, and UV light, for the recovery of the NO2 sensitive materials. The sensor is based on a multimode fiber tip coated with a thin film of lutetium bisphthalocyanine (LuPc2). The simultaneous injection of UV light through the fiber is an improvement on the previously developed NO2 sensors and allows the simplification of the sensor head, rendering the external UV illumination of the film unnecessary. Coatings of different thicknesses were deposited on the optical fiber tips and the best performance was obtained for a 15 nm deposited thickness, with a sensitivity of 5.02 mV/ppm and a resolution of 0.2 ppb in the range 0-5 ppm. The response and recovery times are not dependent on thickness, meaning that NO2 does not diffuse completely in the films.

  10. Investigation of interference in multiple-input multiple-output wireless transmission at W band for an optical wireless integration system.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Dong, Ze; Zhang, Junwen; Chi, Nan; Yu, Jianguo

    2013-03-01

    We experimentally investigate the interference in multiple-input multiple-output (MIMO) wireless transmission by adjusting the relative locations of horn antennas (HAs) in a 100 GHz optical wireless integration system, which can deliver a 50 Gb/s polarization-division-multiplexing quadrature-phase-shift-keying signal over 80 km single-mode fiber-28 and a 2×2 MIMO wireless link. For the parallel 2×2 MIMO wireless link, each receiver HA can only get wireless power from the corresponding transmitter HA, while for the crossover ones, the receiver HA can get wireless power from two transmitter HAs. At the wireless receiver, polarization demultiplexing is realized by the constant modulus algorithm (CMA) in the digital-signal-processing part. Compared to the parallel case, wireless interference causes about 2 dB optical signal-to-noise ratio penalty at a bit-error ratio (BER) of 3.8×10(-3) for the crossover cases if similar CMA taps are employed. The increase in CMA tap length can reduce wireless interference and improve BER performance. Furthermore, more CMA taps should be adopted to overcome the severe wireless interference when two pairs of transmitter and receiver HAs have different wireless distances.

  11. Real-time optical wireless transmissions of digital TV signals using white InGaN LEDs grown with an asymmetric quantum barrier.

    Science.gov (United States)

    Tsai, Chia-Lung; Chen, Yen-Jen

    2015-10-19

    The feasibility of using InGaN LEDs grown with asymmetric barrier layer (ABL) as transmitters in visible light communications is investigated experimentally. Compared with normal LEDs, the improvement in the spontaneous emission rate due to enhanced carrier localization and better uniformity of carrier distribution in ABL-containing MQWs leads to the fabricated LEDs can exhibit a 32.6% (@ 350 mA) increase in emission intensity and a 10.5% increase in modulation bandwidth. After eliminating the slow-responding phosphorescent components emitting from the phosphor-converted white LEDs, an open eye-diagram at 180 Mb/s is demonstrated over a distance of 100 cm in directed line-of-sight optical links. With the use of proposed LEDs, real-time transmissions of digital TV signals over a moderate distance (~100 cm) in free space is shown to be available in a 150 Mbit/s white LED-based optical link with conventional on-off keying modulation.

  12. Transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz

    Science.gov (United States)

    Zaldívar Huerta, Ignacio E.; Pérez Montaña, Diego F.; Nava, Pablo Hernández; Juárez, Alejandro García; Asomoza, Jorge Rodríguez; Leal Cruz, Ana L.

    2013-12-01

    We experimentally demonstrate the use of an electro-optical transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz. The frequency response of the microwave photonic filter consists of four band-pass windows centered at frequencies that can be tailored to the function of the spectral free range of the optical source, the chromatic dispersion parameter of the optical fiber used, as well as the length of the optical link. In particular, filtering effect is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.5 μm associated to the length of a dispersive optical fiber. Filtered microwave signals are used as electrical carriers to transmit TV-signal over long-haul optical links point-to-point. Transmission of TV-signal coded on the microwave band-pass windows located at 4.62, 6.86, 4.0 and 6.0 GHz are achieved over optical links of 25.25 km and 28.25 km, respectively. Practical applications for this approach lie in the field of the FTTH access network for distribution of services as video, voice, and data.

  13. Improvement of the chromatic dispersion tolerance in coherent optical OFDM systems using shifted DFT windows for ultra-long-haul optical transmission systems.

    Science.gov (United States)

    Sung, Minkyu; Kim, Hoon; Lee, Jaehoon; Jeong, Jichai

    2014-09-22

    In a high-capacity ultra-long-haul optical coherent orthogonal frequency-division multiplexing (CO-OFDM) system, the dispersion tolerance is determined by the length of cyclic extension (CE). In this paper, we propose a novel scheme to substantially improve the dispersion tolerance of CO-OFDM systems without increasing the CE length. Multiple time-shifted discrete Fourier transform (DFT) windows are exploited at the receiver, each demodulating only a part of the subcarriers. Effectively, the proposed scheme reduces the bandwidth of the OFDM signals under demodulation. Numerical simulations are performed to show the improved dispersion tolerance of the proposed scheme in comparison with the conventional CO-OFDM system. We show that the dispersion tolerance improves by a factor equal to the number of DFT windows. The tradeoff between the improved dispersion tolerance and increased receiver complexity is also presented.

  14. MO-A-BRD-01: An Investigation of the Dynamic Response of a Novel Acousto-Optic Liquid Crystal Detector for Full-Field Transmission Ultrasound Breast Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfield, J.R.; La Riviere, P.J. [The University of Chicago, Department of Radiology (United States); Sandhu, J.S. [Santec Systems Inc., Arlington Heights, IL (United States)

    2014-06-15

    Purpose: To characterize the dynamic response of a novel acousto-optic (AO) liquid crystal detector for high-resolution transmission ultrasound breast imaging. Transient and steady-state lesion contrast were investigated to identify optimal transducer settings for our prototype imaging system consistent with the FDA limits of 1 W/cm{sup 2} and 50 J/cm{sup 2} on the incident acoustic intensity and the transmitted acoustic energy flux density. Methods: We have developed a full-field transmission ultrasound breast imaging system that uses monochromatic plane-wave illumination to acquire projection images of the compressed breast. The acoustic intensity transmitted through the breast is converted into a visual image by a proprietary liquid crystal detector operating on the basis of the AO effect. The dynamic response of the AO detector in the absence of an imaged breast was recorded by a CCD camera as a function of the acoustic field intensity and the detector exposure time. Additionally, a stereotactic needle biopsy breast phantom was used to investigate the change in opaque lesion contrast with increasing exposure time for a range of incident acoustic field intensities. Results: Using transducer voltages between 0.3 V and 0.8 V and exposure times of 3 minutes, a unique one-to-one mapping of incident acoustic intensity to steady-state optical brightness in the AO detector was observed. A transfer curve mapping acoustic intensity to steady-state optical brightness shows a high-contrast region analogous to the linear portion of the Hurter-Driffield curves of radiography. Using transducer voltages between 1 V and 1.75 V and exposure times of 90 s, the lesion contrast study demonstrated increasing lesion contrast with increasing breast exposure time and acoustic field intensity. Lesion-to-background contrast on the order of 0.80 was observed. Conclusion: Maximal lesion contrast in our prototype system can be obtained using the highest acoustic field intensity and the

  15. Optical Determination of Lead Chrome Green in Green Tea by Fourier Transform Infrared (FT-IR) Transmission Spectroscopy

    Science.gov (United States)

    Li, Xiaoli; Xu, Kaiwen; Zhang, Yuying; Sun, Chanjun; He, Yong

    2017-01-01

    The potential of Fourier transform infrared (FT-IR) transmission spectroscopy for determination of lead chrome green in green tea was investigated based on chemometric methods. Firstly, the qualitative analysis of lead chrome green in tea was performed based on partial least squares discriminant analysis (PLS-DA), and the correct rate of classification was 100%. And then, a hybrid method of interval partial least squares (iPLS) regression and successive projections algorithm (SPA) was proposed to select characteristic wavenumbers for the quantitative analysis of lead chrome green in green tea, and 19 wavenumbers were obtained finally. Among these wavenumbers, 1384 (C = C), 1456, 1438, 1419(C = N), and 1506 (CNH) cm-1 were the characteristic wavenumbers of lead chrome green. Then, these 19 wavenumbers were used to build determination models. The best model was achieved by least squares support vector machine (LS-SVM)algorithm with high coefficient of determination and low root-mean square error of prediction set (R2p = 0.864 and RMSEP = 0.291). All these results indicated the feasibility of IR spectra for detecting lead chrome green in green tea. PMID:28068348

  16. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves through polarization-insensitive optical parametric amplification enabling transmission over 4000-km dispersion-managed TWRS fiber

    DEFF Research Database (Denmark)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S.;

    2013-01-01

    We experimentally demonstrate the first Tb/s Nyquist-WDM phase-conjugated twin waves, consisting of eight 128-Gb/s PDM-QPSK signals and their idlers, by a broadband polarization-insensitive fiber optical parametric amplifier, enabling more than doubled reach in dispersion-managed transmission. © ...

  17. VIDEO TRANSMISSION SYSTEM IN ITV APPLICATION

    Institute of Scientific and Technical Information of China (English)

    WangYancai; WangQunwei; WangZhaohui

    1996-01-01

    The transmission characteristics of video transmission mediums,coaxial cable and optical fiber ,are discussed in the paper. The formulas for frequency bandwidthare given to evaluate the video transmission distance. For typical video transmissionsystems with BB/IM and PFM/IM using optical fiber as the channel, expressions andcalculating results for both SIN and sensitivity are given. Finally. the principle for selecting different type of transmission systems according to transmission distances of the industrial TV is presented.

  18. Transmission of Duobinary Signal in Optical 40 GHz Millimeter-Wave Radio-Over-Fiber Systems Utilizing Dual-Arm LiNbO3 Mach-Zehnder Modulator for Downstream

    Science.gov (United States)

    Dong-Nhat, Nguyen; Malekmohammadi, Amin

    2016-06-01

    In this paper, for the first time transmission of 2.5 Gb/s duobinary signal is investigated for the downlink direction in 40 GHz optical millimeter-wave generation or up-conversion, utilizing a dual-arm LiNb{O}_3 Mach-Zehnder modulator based on different modulation schemes, namely double- and single-sideband (DSB and SSB) and optical carrier suppression (OCS). The up-converted optical millimeter-wave employing OCS modulation scheme indicates the highest back-to-back received optical power and the smallest power penalty after long propagation in the single-mode fiber, in comparison to DSB and SSB. Directly modulated laser in association with OCS modulation scheme has been used to generate duobinary optical millimeter-wave signal in order to minimize the cost and complexity of the system.

  19. Transmission delay and temperature variations in overhead optic links installed along distribution lines due to meteorological effects; Haidensen tenka hikari cable senro no denso chien to ondo no hendo tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Y.; Myosin, M.; Kitamura, K. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1996-03-01

    Transmission delay and temperature variation characteristics in overhead fiber optic links were measured by the whole system time synchronous network evaluation test unit, to clarify the relation between the above and meteorological conditions. The transmission delay measured in the round-trip 25 km overhead links showed daily variations, which was the same as the OPGW (optical ground wire) line. As a result of the regression analysis using meteorological conditions, the transmission delay variation at 5:00 in early morning was greatly affected by the atmospheric temperature, and that at 13:00 in the daytime was affected greatly by the atmospheric temperature and the solar radiation. The coefficients of delay variation with respect to atmospheric temperature were 82 to 97 ps/km/{degree}C for a 48-core cable with 6-core optical fiber unit structure, and 70 to 84 ps/km/{degree}C for a 128-core cable using two-package-core cable. The coefficients depended greatly on the cable structure including OPGW. For the relation between the transmission delay and the mean temperature of cable in the total length, or meteorological conditions, the cable temperature rose more than 10{degree}C at maximum due to solar radiation. Increase of the cable temperature due to solar radiation could be easily estimated only from the atmospheric temperature and delay data. 9 refs., 13 figs.

  20. X波段可编程光钎传输微波延迟系统%X-Band Programmable Optical Fiber Transmission Delay Systems

    Institute of Scientific and Technical Information of China (English)

    马玉培

    2011-01-01

    介绍了X波段可编程光纤传输微波延迟系统的基本工作原理及系统组成.叙述了该系统的研制过程,包括:光发射模块、光接收模块和光纤延迟链路的设计.微波延迟系统具有低插入损耗、低延迟相关损耗,输出幅度稳定,快速延迟切换速度(<0.5ms)等优点以及单板机编程和计算机控制界面.该延迟系统传输微波频率范围:9~11GHz,延迟时间范围为1.0133~1.6467μs,延迟精度为0.5ns,延迟时间可以在1.0133~1.6467μs范围内步进调节,延迟时间控制实现了计算机控制.%The operational principle and system configuration of the X-band programmable optical fiber transmission delay system was presented. The process design of the system was introduced,including the light emission module, the light receive module and the design of optical delay line. The optical delay system ia also with the characteristics of low insertion loss, low delay loss, stable output level, speedily delay switch and computer control, etc. The frequency range is 9 - 11 GHz, the internal delay spool range is 1. 013 3 - 1. 646 7 μs and the delay time precision is 0. 5 ns. The delay time can be achieved by step-by-step regulation with the computer during the range of 1. 013 3 - 1. 646 7 μs.

  1. In-situ investigation of the order-disorder transition in Cu2ZnSnSe4 by optical transmission spectroscopy

    Directory of Open Access Journals (Sweden)

    Christiane Stroth

    2017-02-01

    Full Text Available The existence of disorder is one possible reason for the limited performance of kesterite solar cells. Therefore further knowledge of the order-disorder phase transition, of factors which influence the degree of order and of methods to determine this material property is still required. In this study we investigated the order-disorder transition in the kesterite material Cu2ZnSnSe4 by in-situ optical transmission spectroscopy during heat treatments. We show in-situ results for the temperature dependence of the band gap and its tailing properties. The influence of cooling rates on the phase transition was analyzed as well as the ordering kinetics during annealing at a constant temperature. The critical temperature of the phase transition was determined and the existence of a control temperature range is shown, which allows for controlling the degree of order by the cooling rate within this range. Additionally we performed Raman analysis to link Raman spectra to the degree of order in Cu2ZnSnSe4. A correlation between the intensity ratio of A-modes as well as B-/ E- Raman modes and the degree of order was found.

  2. Study of EDFA and Raman system transmission reach with 256 Gb/s PM-16QAM signals over three optical fibers with 100 km spans.

    Science.gov (United States)

    Downie, John D; Hurley, Jason; Pikula, Dragan; Ten, Sergey; Towery, Chris

    2013-07-15

    We compare the transmission performance of three different optical fibers in separate 256 Gb/s PM-16QAM systems amplified with erbium doped fiber amplifiers (EDFAs) and distributed Raman amplification. The span length in each system is 100 km. The fibers studied include standard single-mode fiber, single-mode fiber with ultra-low loss, and ultra-low loss fiber with large effective area. We find that the single-mode fiber with ultra-low loss and the large effective area fiber with ultra-low loss afford reach advantages of up to about 31% and 80%, respectively, over standard fiber measured at distances with 3 dB margin over the forward error correction (FEC) threshold. The Raman amplified systems provide about 50% reach length enhancement over the EDFA systems for all three fibers in the experimental set-up. For the best performing fiber with large effective area and ultra-low loss, the absolute reach lengths with 3 dB margin are greater than 1140 km and 1700 km for the for EDFA and Raman systems, respectively.

  3. Fabrication of nanostructured transmissive optical devices on ITO-glass with UV1116 photoresist using high-energy electron beam lithography

    Science.gov (United States)

    Williams, Calum; Bartholomew, Richard; Rughoobur, Girish; Gordon, George S. D.; Flewitt, Andrew J.; Wilkinson, Timothy D.

    2016-12-01

    High-energy electron beam lithography for patterning nanostructures on insulating substrates can be challenging. For high resolution, conventional resists require large exposure doses and for reasonable throughput, using typical beam currents leads to charge dissipation problems. Here, we use UV1116 photoresist (Dow Chemical Company), designed for photolithographic technologies, with a relatively low area dose at a standard operating current (80 kV, 40-50 μC cm-2, 1 nAs-1) to pattern over large areas on commercially coated ITO-glass cover slips. The minimum linewidth fabricated was ˜33 nm with 80 nm spacing; for isolated structures, ˜45 nm structural width with 50 nm separation. Due to the low beam dose, and nA current, throughput is high. This work highlights the use of UV1116 photoresist as an alternative to conventional e-beam resists on insulating substrates. To evaluate suitability, we fabricate a range of transmissive optical devices, that could find application for customized wire-grid polarisers and spectral filters for imaging, which operate based on the excitation of surface plasmon polaritons in nanosized geometries, with arrays encompassing areas ˜0.25 cm2.

  4. Optical and structural properties in type-II InAlAs/AlGaAs quantum dots observed by photoluminescence, X-ray diffraction and transmission electron microscopy

    Science.gov (United States)

    Ben Daly, A.; Craciun, D.; Laura Ursu, E.; Lemaître, A.; Maaref, M. A.; Iacomi, F.; Vasile, B. S.; Craciun, V.

    2017-10-01

    We present the effects of AlGaAs alloy composition on InAlAs quantum dots (QDs) optical and structural properties. Photoluminescence (PL) analysis of samples having a variety of aluminium composition values covering type-II transitions clearly in QDs showed the presence of two transitions X-Sh and X-Ph. High-resolution X-ray diffraction (HRXRD) investigations showed that the layers grew epitaxially on the GaAs substrate, with no relaxation regardless the Al content of AlGaAs layer. From the reciprocal space map (RSM) investigation around (004) and (115) diffraction peaks, it was shown that the InAlAs layer is fully strained, the in-plane lattice parameters (a and b, a = b) being identical to those of GaAs substrate, while the c lattice parameter was dependent on the In and Al concentrations, being larger than that of the substrate. High-resolution transmission electronic microscopy (HRTEM) investigations confirmed that films grew epitaxially on the GaAs substrate with no visible dislocations or other major defects within the InAlAs/GaAlAs QDs structure.

  5. Application of Optical Fiber Data Transmission Technology into Digital Array Radar%光纤传输技术在数字阵列雷达中的应用

    Institute of Scientific and Technical Information of China (English)

    赵磊; 郭文卓

    2011-01-01

    随着数字阵列雷达的发展,天线阵面与控制中心之间需要交换的数据量越来越大,在这种情况下,光纤传输技术由于抗干扰性强、传输容量大等优点而被广泛采用.波分复用技术和光纤滑环技术的日渐成熟使得光纤传输系统在数字阵列雷达中的应用具备了工程可实现性.首先给出了典型的光纤传输系统构建方案,然后对光纤传输中的关键技术实现、光链路故障的检测和定位等做了分析.该方案已在某雷达中成功应用,性能稳定可靠.%With the development of digital array radar, the amount of data to be exchanged between antenna and control center is increasing remarkablely. To meet such requirements, optical fiber technology for data transmission has received extensive attention because of its high anti-interference performance and high transmission capacity. With the advancement of the techniques of wavelength division multiplexing (WDM) and fiber optic rotary joint, optical fiber data transmission now is applicable in digital array radar system. In this paper, a typical optical fiber transmission scheme is presented, and the analysis on the key technology and the fault detection and position of optical link is also performed. The scheme proposed is being successfully applied into certain radar product, and the performance is proved to be effective and reliable.

  6. Optical fibre-lightning arrester cable appliances. Its repercussion in concrete unconventional power transmission lines projects; Aplicacao de cabo para-raios composto com fibra optica. Sua repercursao em projetos de LT`s concreto nao convencionais

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Ramon Sade [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

    1993-12-31

    With the adoption of lightning rod cables made of Optical Fibre, (in systems over Europe, Japan and North America), these became very popular in Countries capable of installing the system. The Brazilian electrical party was then challenged by a new technological experience: the lightning rod cable for lines of transmission has specific characteristics. The particularity of the electrical system in Brazil in relation to the diversity of the parameters involved, and the necessity to clarifying the concepts, take us to new strategies in planning and measuring our Power Transmission Lines 4 refs., 1 tab.

  7. WDM Transmission over 320 km EDFA-Amplified SSMF Using 30 Gb/s Return-to-Zero Optical Differential 8-Level Phase-Shift Keying (OD8PSK).

    Science.gov (United States)

    Kim, Cheolhwan; Goldfarb, Gilad; Han, Yan; Li, Zhihong; Li, Xiaoxu; Li, Guifang

    2005-05-30

    Fiber transmission of optical differential 8-level phase-shift keying (OD8PSK) signals is demonstrated for the first time. Co-polarized 8 WDM channels of 10 Giga-symbol/s or 30 Gb/s return-to-zero (RZ) OD8PSK signals with a channel spacing of 50 GHz were transmitted over 320 km of standard single mode fiber (SSMF) with an EDFA spacing of 80 km. The BER of the worst WDM channel after transmission of 320 km was 2.3x10-5.

  8. Different optical spectral characteristics in a necrotic transmissible venereal tumor and a cystic lesion in the same canine prostate observed by triple-band trans-rectal optical tomography under trans-rectal ultrasound guidance

    Science.gov (United States)

    Jiang, Zhen; Holyoak, G. Reed; Ritchey, Jerry W.; Bartels, Kenneth E.; Rock, Kendra; Ownby, Charlotte L.; Slobodov, Gennady; Bunting, Charles F.; Piao, Daqing

    2011-03-01

    Different optical spectral characteristics were observed in a necrotic transmissible venereal tumor (TVT) and a cystic lesion in the same canine prostate by triple-wavelength trans-rectal optical tomography under trans-rectal ultrasound (TRUS) guidance. The NIR imager acquiring at 705nm, 785nm and 808nm was used to quantify both the total hemoglobin concentration (HbT) and oxygen saturation (StO2) in the prostate. The TVT tumor in the canine prostate as a model of prostate cancer was induced in a 7-year old, 27 kg dog. A 2 mL suspension of 2.5x106 cells/mL of homogenized TVT cells recovered from an in vivo subcutaneously propagated TVT tumor in an NOD/SCID mouse were injected in the cranial aspect of the right lobe of the canine prostate. The left lobe of the prostate had a cystic lesion present before TVT inoculation. After the TVT homogenate injection, the prostate was monitored weekly over a 9-week period, using trans-rectal NIR and TRUS in grey-scale and Doppler. A TVT mass within the right lobe developed a necrotic center during the later stages of this study, as the mass presented with substantially increased [HbT] in the periphery, with an area of reduced StO2 less than the area of the mass itself shown on ultrasonography. Conversely, the cystic lesion presented with slightly increased [HbT] in the periphery of the lesion shown on ultrasound with oxygen-reduction inside and in the periphery of the lesion. There was no detectable change of blood flow on Doppler US in the periphery of the cystic lesion. The slightly increased [HbT] in the periphery of the cystic lesion was correlated with intra-lesional hemorrhage upon histopathologic examination.

  9. Discussion on Course of The SDH Optical Transmission Technology%《SDH光传输技术》教学探讨

    Institute of Scientific and Technical Information of China (English)

    宫海梅

    2016-01-01

    《SDH光传输技术》课程是移动通信专业核心课,也是一门职业技能课。如何让学生经过课程学习后较快适应工作岗位是迫切需要解决的问题。从课程地位、课程目标、教学内容设置、课程实施、教学评价及考核要求、改革成效这几方面进行探讨,在具体教学过程中采用基于工作过程导向的任务驱动教学法,以学生为本,理论与实践相结合,教学做一体化,在教学评价及考核中,采用分阶段分层次过程考核,提高了学生积极性,为适应岗位工作奠定良好基础。%The SDH optical transmission technology is a mobile communications professional core cour-ses , and is a professional skill courses .How to make students quickly adapt to the job after a course is an ur-gent need to solve the problem .This article are discussed from the curriculum status , curriculum objectives , teaching content , curriculum implementation to teaching evaluation and requirements , the result of reform .In the process of teaching ,the task driven teaching method is adopted based on working process .Give priority to students , combine theory and practice , integrated teaching study and doing as a whole .In the teaching e-valuation and requirements , using the phases hierarchical process , improve the enthusiasm of the students in order to meet the post work .

  10. Transmission Properties of Fiber Probes

    Institute of Scientific and Technical Information of China (English)

    XUE Chun-rong; ZHU Sheng-xiang; XIAO Zhi-gang

    2004-01-01

    Transmission properties of tapered fiber including right cone fiber and bend optical fiber are discussed. The transmission efficiency of the tapered fiber is measured. The curve of transmission efficiency versus taper cone angle is given. By the scalar wave equation and Gaussian approximation, transmission properties of the two kinds of tapered fibers are analyzed, the power losses caused by taper cone angle and by the bending are also calculated. From the experiments and theoretical analysis, it could come to a conclusion that the wider the taper cone angle is, the higher the transmission efficiency will be.

  11. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves by a polarization-insensitive optical parametric amplifier for fiber-nonlinearity-tolerant transmission

    DEFF Research Database (Denmark)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S.;

    2014-01-01

    -optical signal processing approach to generate WDM-PCTWs enables a 2-fold reduction in the needed optical transmitters as compared to the conventional approach where each idler is generated by a dedicated transmitter. Digital coherent superposition of the twin waves at the receiver enables more than doubled......We experimentally demonstrate the generation of 1.024-Tb/s Nyquist-WDM phase-conjugated vector twin waves (PCTWs), consisting of eight 128-Gb/s polarization-division-multiplexed QPSK signals and their idlers, by a broadband polarization-insensitive fiber optic parametric amplifier. This novel all...... reach in a dispersion-managed transmission link. We further study the impact of polarization-mode dispersion on the performance gain brought by the phase-conjugated twin waves, showing a gain of ∼3.8 dB in signal quality factors....

  12. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves by a polarization-insensitive optical parametric amplifier for fiber-nonlinearity-tolerant transmission.

    Science.gov (United States)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S; Jopson, R M; Gnauck, A H; Dinu, M; Xie, C; Winzer, P J

    2014-03-24

    We experimentally demonstrate the generation of 1.024-Tb/s Nyquist-WDM phase-conjugated vector twin waves (PCTWs), consisting of eight 128-Gb/s polarization-division-multiplexed QPSK signals and their idlers, by a broadband polarization-insensitive fiber optic parametric amplifier. This novel all-optical signal processing approach to generate WDM-PCTWs enables a 2-fold reduction in the needed optical transmitters as compared to the conventional approach where each idler is generated by a dedicated transmitter. Digital coherent superposition of the twin waves at the receiver enables more than doubled reach in a dispersion-managed transmission link. We further study the impact of polarization-mode dispersion on the performance gain brought by the phase-conjugated twin waves, showing a gain of ~3.8 dB in signal quality factors.

  13. SDH光传输技术在电力通信系统中的应用分析%Application Analysis of SDH Optical Transmission Technology in Electric Power Communication System

    Institute of Scientific and Technical Information of China (English)

    林旭升

    2015-01-01

    基于SDH光传输技术的电力通信系统作为保障电力系统安全、稳定的重要组成部分,在经过多年的发展之后已经逐渐走向成熟,但目前还存在着诸多的问题:如通信网网络结构薄弱、网络传输容量不足、网络接入和网络管理薄弱等,因此有必要对基于SDH光传输技术的电力通信系统进行研究,文章结合实例对SDH光传输技术在电力通信系统中的应用进行了分析,可为相关工作者提供参考.%The electric power communication system based on SDH optical transmission technology is an important part of power system security and stability, after years of development, it has gradually matured, but there are still many problems: such as communication network structure is weak, the network transmission capacity is insufficient, network access and network management is weak etc.. Therefore, it is necessary to research on SDH optical transmission technology in electric power communication system based on, this paper combined the example has carried on the analysis to the application of SDH optical transmission technology in electric power communication system, can provide a reference for relevant workers.

  14. Transmission analysis in WDM networks

    DEFF Research Database (Denmark)

    Rasmussen, Christian Jørgen

    1999-01-01

    This thesis describes the development of a computer-based simulator for transmission analysis in optical wavelength division multiplexing networks. A great part of the work concerns fundamental optical network simulator issues. Among these issues are identification of the versatility and user...... with a view of reducing the required number of bits....

  15. Nonlocal Effects on Optical Transmission Spectrum in a P(o)schl-Teller Quantum Well%P(o)schl-Teller势阱中非局域效应对透射光谱的影响

    Institute of Scientific and Technical Information of China (English)

    王光辉

    2013-01-01

    Analytic expression for optical transmission spectrum is obtained by utilizing the Green function method in the case of nonlocal optical responses of electrons in the conduction band of quantum wells.Optical transmission spectra for typical GaAs/A1GaAs quantum wells of a P(o)schl-Teller potential are investigated in detail.The numerical results show that optical transmission spectrum has an evident blueshift due to the nonlocal optical responses of electrons to applied laser fields,which is dependent closely on the width of the quantum wells.In the effective nano-size region,the wider the width of the quantum well is,the more the blueshift will be.In addition,the influence from the laser intensity and the structure parameter on the transmission spectrum is also analyzed.%在考虑半导体量子阱中导带电子对外加激光场非局域光学响应的情况下,利用格林函数方法推导出了光透射率的解析表达式,并以典型的GaAs/AlGaAs为材料的P(o)schl-Teller量子势阱为例进行数值计算.计算结果表明,由于电子对激光场的非局域光学响应,半导体量子阱的透射光谱的谱线在共振峰附近出现明显地蓝移,蓝移的大小与量子阱宽度有紧密的联系.在有效的纳米尺度范围内,半导体量子阱越宽,透射谱线的蓝移也就越大.另外,光场强度和量子阱结构参数等因素对透射光谱的影响也被澄清.

  16. Optical Solitons

    Science.gov (United States)

    Taylor, J. R.

    2005-08-01

    1. Optical solitons in fibres: theoretical review A. Hasegawa; 2. Solitons in optical fibres: an experimental account L. F. Mollenauer; 3. All-optical long-distance soliton-based transmission systems K. Smith and L. F. Mollenauer; 4. Nonlinear propagation effects in optical fibres: numerical studies K. J. Blow and N. J. Doran; 5. Soliton-soliton interactions C. Desem and P. L. Chu; 6. Soliton amplification in erbium-doped fibre amplifiers and its application to soliton communication M. Nakazawa; 7. Nonlinear transformation of laser radiation and generation of Raman solitons in optical fibres E. M. Dianov, A. B. Grudinin, A. M. Prokhorov and V. N. Serkin; 8. Generation and compression of femtosecond solitons in optical fibers P. V. Mamyshev; 9. Optical fibre solitons in the presence of higher order dispersion and birefringence C. R. Menyuk and Ping-Kong A. Wai; 10. Dark optical solitons A. M. Weiner; 11. Soliton Raman effects J. R. Taylor; Bibliography; Index.

  17. 320 Gb/s Single polarization OTDM Transmission over 80 km Standard Transmission Fiber

    DEFF Research Database (Denmark)

    Siahlo, Andrei; Seoane, Jorge; Clausen, Anders;

    2005-01-01

    Optical time-division multiplexing (OTDM) is an attractive technique for increasing the capacity of optical transmission systems. 320 Gbit/s single-channel and single-polarization error-free transmission over continuous spans of either 80 km SMF or 77 km NZDSF are realized.......Optical time-division multiplexing (OTDM) is an attractive technique for increasing the capacity of optical transmission systems. 320 Gbit/s single-channel and single-polarization error-free transmission over continuous spans of either 80 km SMF or 77 km NZDSF are realized....

  18. Nonreciprocal light transmission based on the thermal radiative effect

    DEFF Research Database (Denmark)

    Liu, Li; Dong, Jianji; Ding, Yunhong

    2015-01-01

    Nonreciprocal light transmission is critical in building optical isolations and circulations in optical communication systems. Achieving high optical isolation and broad bandwidth with CMOS-compatibility are still difficult in silicon nano-photonics. Here we first experimentally demonstrate that ...

  19. Transmission eigenvalues

    Science.gov (United States)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  20. Advanced Silicon Photonic Transceivers - the Case of a Wavelength Division and Polarization Multiplexed Quadrature Phase Shift Keying Receiver for Terabit/s Optical Transmission

    Science.gov (United States)

    2017-03-10

    Component Analyzer ( LCA ) and is shown in Fig. 3. The transimpedance (RF) of the TIA was swept over the range of possible values, i.e. R! = 400 Ω/N with N...Optical signal to noise ratio VOA variable optical attenuator ASE amplified spontaneous emission LO local oscillator TX transmitter LCA lightwave