WorldWideScience

Sample records for acousto optic modulators

  1. Fiber Acousto-Electro-Optic Modulator

    Institute of Scientific and Technical Information of China (English)

    Anen; Jiang

    2003-01-01

    A new kind of fiber acousto-electro-optic modulator is made by using Lithium Niobate crystal. This kind of modulator can be used in fiber communication, and its center frequency can be changed by directed current voltages.

  2. Acousto-optic modulation of a photonic crystal nanocavity with Lamb waves in microwave K band

    Energy Technology Data Exchange (ETDEWEB)

    Tadesse, Semere A. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Li, Huan; Liu, Qiyu; Li, Mo, E-mail: moli@umn.edu [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-11-16

    Integrating nanoscale electromechanical transducers and nanophotonic devices potentially can enable acousto-optic devices to reach unprecedented high frequencies and modulation efficiency. Here, we demonstrate acousto-optic modulation of a photonic crystal nanocavity using Lamb waves with frequency up to 19 GHz, reaching the microwave K band. The devices are fabricated in suspended aluminum nitride membrane. Excitation of acoustic waves is achieved with interdigital transducers with period as small as 300 nm. Confining both acoustic wave and optical wave within the thickness of the membrane leads to improved acousto-optic modulation efficiency in these devices than that obtained in previous surface acoustic wave devices. Our system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.

  3. Fiber-optic tunable multiwavelength variable attenuator and routing module designs that use bulk acousto-optics.

    Science.gov (United States)

    Riza, Nabeel A; Mughal, M Junaid

    2005-02-10

    A compact fiber-coupled bulk acousto-optical multiwavelength variable optical attenuator module design that uses a retroreflective double-pass geometry within a single bulk acousto-optic tunable filter device is presented. The proposed attenuator module demonstrates a high 17-dB notch dynamic range at a low 100-mW drive power and uses a single bulk collinear-interaction acousto-optic tunable-filter device. Experiments show a low (design is extended to allow for efficient architectures for routing modules such as agile drop filters, analog hitless tap filters, and digital add-drop switches.

  4. High-speed optical correlation-domain reflectometry without using acousto-optic modulator

    CERN Document Server

    Shizuka, Makoto; Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2015-01-01

    To achieve a distributed reflectivity measurement along an optical fiber, we develop a simplified cost-effective configuration of optical correlation- (or coherence-) domain reflectometry based on a synthesized optical coherence function by sinusoidal modulation. By excluding conventional optical heterodyne detection (practically, without using an acousto-optic modulator) and by exploiting the foot of the Fresnel reflection spectrum, the electrical bandwidth required for signal processing is lowered down to several megahertz. We evaluate the basic system performance and demonstrate its high-speed operation (10 ms for one scan) by tracking a moving reflection point in real time.

  5. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns

    International Nuclear Information System (INIS)

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical phase modulation, the fraction of light that is tagged by ultrasound, speckle contrast, mean square difference of speckle patterns and the contrast of the summation of speckle patterns acquired at different ultrasound phases. We derive the important relations from basic assumptions and definitions, and then validate them with simulations. For ultrasound-generated phase modulation angles below 0.7 rad (assuming uniform modulation), we are now able to relate speckle pattern statistics to the acousto-optic phase modulation. Hence our theory allows quantifying speckle observations in terms of ultrasonically tagged fractions of light for near-unity-contrast speckle patterns. (paper)

  6. Acousto-optic and opto-acoustic modulation in piezo-optomechanical circuits

    CERN Document Server

    Balram, Krishna C; Ilic, B Robert; Kyhm, Ji-Hoon; Song, Jin Dong; Srinivasan, Kartik

    2016-01-01

    Acoustic wave devices provide a promising chip-scale platform for efficiently coupling radio frequency (RF) and optical fields. Here, we use an integrated piezo-optomechanical circuit platform that exploits both the piezoelectric and photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm) optical waves, through coupling to propagating and localized 2.4 GHz acoustic waves. We demonstrate acousto-optic modulation, resonant in both the optical and mechanical domains, in which waveforms encoded on the RF carrier are mapped to the optical field. We also show opto-acoustic modulation, in which the application of optical pulses gates the transmission of propagating acoustic waves. The time-domain characteristics of this system under both pulsed RF and pulsed optical excitation are considered in the context of the different physical pathways involved in driving the acoustic waves, and modeled through the coupled mode equations of cavity optomechanics.

  7. Laser communication system with acousto-optic tracking and modulation: experimental study

    Science.gov (United States)

    Nikulin, Vladimir V.; Sofka, Jozef

    2009-12-01

    Laser communication systems are highly preferred for broadband applications. This technology uses higher regions of the spectrum, and offers unsurpassed throughput, information security, reduced weight and size of the components, and power savings. Unfortunately, small beam divergence requires precise positioning, which becomes very critical at high data rates. Complex motion patterns of the communicating platforms, vibrations, and atmospheric effects cause significant signal losses due to the pointing errors, beam wander, and other higher order effects. Mitigation of those effects is achieved by fast tracking, which can be successfully combined with signal modulation. In this work, we focus on the application of acousto-optic technology and its effect on communication performance. We present experimental results for a laser communication link affected by pointing distortions. These distortions are generated to emulate specific operation environments with particular spectral characteristics. The acousto-optic technology is used to build an agile tracking system combined with signal modulation in the same device to assure maximum signal reception, in spite of the harsh operational conditions. The received communication signal is recorded and statistically analyzed to calculate the bit error rates. This work presents synthesis of a tracking system and experimental results characterizing the communication performance under uncompensated pointing disturbance and with tracking.

  8. LIGHT MODULATION: Quasi-collinear tunable acousto-optic paratellurite crystal filters for wavelength division multiplexing and optical channel selection

    Science.gov (United States)

    Molchanov, V. Ya; Voloshinov, V. B.; Makarov, O. Yu

    2009-04-01

    Quasi-collinear acousto-optic interaction is studied in acoustically and optically anisotropic paratellurite crystals. The possible applications of this interaction in acousto-optic tunable filters with a high spectral resolution are discussed. Different modifications of devices are compared and variants of devices intended for processing light beams and selection of light signals in fibreoptic communication systems with wavelength division multiplexing (WDM) at λ simeq 1550 nm are considered.

  9. Acousto-Optic Devices For Use In Radio Frequency Target Simulators

    Science.gov (United States)

    Kirchner, Ernst K.

    1980-01-01

    Acousto-optic devices have been analyzed and developed for use as modulators, filters and correlators, and in spectrum analyzers. The ability of the acousto-optic unit to amplitude-modulate, frequency-modulate, and deflect laser beams, makes them suitable for these applications. The various signal processing and control functions provided by the acousto-optic devices are optimized by controlling the ratio of divergence angles of the optical beam and the acoustic beam in the acousto-optic interaction region. Another application of acousto-optic devices is to simulate moving targets to test fuzing altimeters and active missile control systems. The frequency modulation, amplitude modulation, and deflection properties of acousto-optic components are all utilized in a single acousto-optic unit to provide the variable range and Doppler simulation. Development of a suitable acousto-optic component for this simulation application is described, as is a description of a simulator employing this acousto-optic device.

  10. Investigation of noise in Lightwave Synthesized Frequency Sweeper seeded LIDAR anemometers from leakage through the Acousto Optic Modulators

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Lindelöw, Per Jonas Petter

    2009-01-01

    Lightwave Synthesized Frequency Sweepers (LSFS) have potential use as lightsources in lidar anemometers. In this paper noise due to leakage in the acousto optic modulators in an LSFS is investigated. Theoretical expressions describing the build-up of noise in the LSFS due to leakage are derived...... Train (FSPT) modulated lidars the leakage will give rise to rapidly growing noise in the bins which corresponds to the signal from low radial wind velocities. It is likely that noise canceling techniques similar to those used for RIN removal has to be deployed for measurements of low wind velocities....

  11. The Experimental Study on Acousto-optic Modulation Based on Single-mode Fiber Fused Coupler

    Institute of Scientific and Technical Information of China (English)

    Liu Guoxiang; Hu Li; Ye Kunzhen; Lin Weigan

    2002-01-01

    In-line acoustic-optic (AO) modulation experiments were demonstrated based on the acoustic-optic effect in optical fiber fused taper couplers.About 73%,64%,and 61% modulation have been achieved at frequencies of 0.169 MHz,0.367 MHz and 0.521 MHz with an electrical driving power less than 10 mW,respectively.

  12. Designing of Acousto-optic Spectrum Analyzer

    Institute of Scientific and Technical Information of China (English)

    WANG Dan-zhi; SHAO Ding-rong; LI Shu-jian

    2004-01-01

    The structure of the acousto-optic spectrum analyzer was investigated including the RF amplifying circuit, the optical structures and the postprocessing circuit, and the design idea of the module was applied to design the spectrum analyzer. The modularization spectrum analyzer takes on the performance stabilization and higher reliability, and according to different demands, the different modules can be used. The spectrum analyzer had such performances as the detecting frequency error of 0.58MHz,detecting responsivity of 90 dBm and bandwidth of 50 Mhz.

  13. An experimental distribution of analog and digital information in a hybrid wireless visible light communication system based on acousto-optic modulation and sinusoidal gratings

    Science.gov (United States)

    Gómez Colín, R.; García Juárez, A.; Zaldívar Huerta, I. E.; Marquina, A. Vera; García Delgado, L. A.; Leal Cruz, A. L.; Gómez Fuentes, R.

    2016-03-01

    In this paper we propose a photonic architecture as an alternative tool to distribute point to multipoint analog and digital information over a hybrid wireless visible optical communication system. The experimental set-up is composed of a red laser pointer, an acousto-optic modulator, a sinusoidal grating and a photo-detector array. By using a simple and variable interferometric system, diffraction gratings with different spatial frequencies are generated and recorded on a photoemulsion which is composed of vanilla with dichromate gelatin. Analog video and digital information are first transmitted and recovered over a wireless communication system using a microwave carrier at 4.52 GHz which is generated by distributed feedback lasers operating in the low laser threshold current region. Separately, the recovered video information and digital data are combined with a radio frequency signal of 80 MHz, obtaining a subcarrier of information that is imposed on the optical carrier of the pointer laser using an acousto-optic modulator which is operated with an angle of incident light that satisfies the Bragg condition. The modulated optical carrier is sent to a sinusoidal grating, the diffraction pattern is photo-detected using an array of PIN photo-detectors. The use of sinusoidal gratings with acousto-optic modulators allows that number of channels to be increased when both components are placed in cascade.

  14. An experimental distribution of analog and digital information in a hybrid wireless visible light communication system based on acousto-optic modulation and sinusoidal gratings

    International Nuclear Information System (INIS)

    In this paper we propose a photonic architecture as an alternative tool to distribute point to multipoint analog and digital information over a hybrid wireless visible optical communication system. The experimental set-up is composed of a red laser pointer, an acousto-optic modulator, a sinusoidal grating and a photo-detector array. By using a simple and variable interferometric system, diffraction gratings with different spatial frequencies are generated and recorded on a photoemulsion which is composed of vanilla with dichromate gelatin. Analog video and digital information are first transmitted and recovered over a wireless communication system using a microwave carrier at 4.52 GHz which is generated by distributed feedback lasers operating in the low laser threshold current region. Separately, the recovered video information and digital data are combined with a radio frequency signal of 80 MHz, obtaining a subcarrier of information that is imposed on the optical carrier of the pointer laser using an acousto-optic modulator which is operated with an angle of incident light that satisfies the Bragg condition. The modulated optical carrier is sent to a sinusoidal grating, the diffraction pattern is photo-detected using an array of PIN photo-detectors. The use of sinusoidal gratings with acousto-optic modulators allows that number of channels to be increased when both components are placed in cascade. (paper)

  15. LIGHT MODULATION: Wide-aperture diffraction of unpolarised radiation in a system of two acousto-optic filters

    Science.gov (United States)

    Magdich, L. N.; Yushkov, K. B.; Voloshinov, V. B.

    2009-04-01

    Light diffraction is studied in two tandem acousto-optic cells filtering unpolarised radiation with a wide angular spectrum. It is shown that the side lobes of the ultrasonic radiation pattern of a piezoelectric transducer produce side diffraction intensity maxima at the output of the system consisting of two filters. Diffraction in paratellurite filters is studied experimentally at 1.06 μm.

  16. Acousto-optic laser optical feedback imaging

    CERN Document Server

    Jacquin, Olivier; Lacot, Eric; Hugon, Olivier; De Chatellus, Hugues Guillet; François, Ramaz

    2012-01-01

    We present a photon noise and diffraction limited imaging method combining the imaging laser and ultrasonic waves. The laser optical feedback imaging (LOFI) technique is an ultrasensitive imaging method for imaging objects through or embedded within a scattering medium. However, LOFI performances are dramatically limited by parasitic optical feedback occurring in the experimental setup. In this work, we have tagged the ballistic photons by an acousto-optic effect in order to filter the parasitic feedback effect and to reach the theoretical and ultimate sensitivity of the LOFI technique. We present the principle and the experimental setup of the acousto-optic laser optical feedback imaging (AO-LOFI) technique, and we demonstrate the suppression of the parasitic feedback.

  17. Electro-optic and Acousto-optic Laser Beam Scanners

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Bechtold, P.

    2014-01-01

    Optical solid state deflectors rely on the electro-optical or acousto-optic effect. These Electro-Optical Deflectors (EODs) and Acousto-Optical Deflectors (AODs) do not contain moving parts and therefore exhibit high deflection velocities and are free of drawbacks associated with mechanical scanners. A

  18. Cavity dumping of neodymium-doped fibre lasers using acousto-optic modulator

    OpenAIRE

    Abdulhalim, I.; Pannell, C.N.; Jedrzejewski, K.P.; Taylor, E.R.

    1994-01-01

    We report high-repetition-rate pulses obtained by cavity dumping of a neodymium-doped phosphate glass fibre laser operating at 1053 nm using a specially constructed acoustooptic modulator. With 27 mW absorbed pump power at 812 nm we obtained stable trains of output pulses with repetition rate in the range 0.5 to 8MHz having corresponding pulse widths in the range 127 to 19 ns without significant sacrifice in the average output power of 8 mW.

  19. Acousto-optic spectrometer for radio astronomy

    Science.gov (United States)

    Chin, G.; Buhl, D.; Florez, J. M.

    1980-01-01

    A prototype acousto-optic spectrometer which uses a discrete bulk acoustic wave Itek Bragg cell, 5 mW Helium Neon laser, and a 1024 element Reticon charge coupled photodiode array is described. The analog signals from the photodiode array are digitized, added, and stored in a very high speed custom built multiplexer board which allows synchronous detection of weak signals to be performed. The experiment is controlled and the data are displayed and stored with an LSI-2 microcomputer system with dual floppy discs. The performance of the prototype acousto-optic spectrometer obtained from initial tests is reported.

  20. Acousto-optic laser projection systems for displaying TV information

    Science.gov (United States)

    Gulyaev, Yu V.; Kazaryan, M. A.; Mokrushin, Yu M.; Shakin, O. V.

    2015-04-01

    This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation.

  1. Isolation of Integrated Optical Acousto-Optic Switch

    Institute of Scientific and Technical Information of China (English)

    XIAO Li-Feng; LIU Ying; WANG Wei-Peng; GENG Fan

    2006-01-01

    @@ Isolation of a new structured acousto-optic switch based on an integrated optical polarization-independent quasicollinear acousto-optic tunable filter is studied in detail. The factors that influence the isolation of the optical switch are analysed, the expressions of the isolation are educed, and the isolation of the device is measured in experiment. It is found that the isolation mainly depends on the TE/TM mode intensity ratio, the mode-splitter extinction rate, and the conversion efficiency.

  2. High-peak-power sub-nanosecond intracavity KTiOPO4 optical parametric oscillator pumped by a dual-loss modulated laser with acousto-optic modulator and single-walled carbon nanotube

    Science.gov (United States)

    Qiao, Junpeng; Zhao, Shengzhi; Yang, Kejian; Zhao, Jia; Li, Guiqiu; Li, Dechun; Li, Tao; Qiao, Wenchao; Lu, Jianren; Wang, Yonggang; Chu, Hongwei; Luan, Chao

    2016-08-01

    A high-peak-power low-repetition-rate sub-nanosecond intracavity KTiOPO4 (KTP) optical parametric oscillator (OPO) pumped by a doubly Q-switched and mode-locked (QML) YVO4/Nd:YVO4 laser with an acousto-optic modulator (AOM) and a single-walled carbon nanotube saturable absorber (SWCNT-SA) has been demonstrated. A maximum output power of 373 mW at a signal wavelength of 1570 nm was obtained. The smallest pulse width, highest pulse energy, and greatest peak power of mode-locking pulses were estimated to be 119 ps, 124 µJ, and 1.04 MW, respectively, under a maximum incident pump power of 8.3 W and an AOM repetition rate of 2 kHz. This OPO operation paves a simple way to produce eye-safe laser sources at 1570 nm with low repetition rates, small pulse widths, and high peak powers.

  3. Polarization-independent operation of an acousto-optical device at the transmit end of a single-laser transmission system using self-heterodyning

    Science.gov (United States)

    Olivier, L.; Rocks, M.

    1991-03-01

    This paper describes the way in which a new integrated acousto-optical LiNbO 3 device combining the three functions of an electro-optical phase modulator, an acousto-optical TE/TM or TM/TE mode converter and an acousto-optical frequency shifter can be operated in a polarization-independent manner as a transmitter unit in a single-laser transmission system using self-heterodyning.

  4. Optical phase noise engineering via acousto-optic interaction and its interferometric applications

    CERN Document Server

    Satapathy, Nandan; Bannerjee, Sourish; Ramachandran, Hema

    2013-01-01

    We exercise rapid and fine control over the phase of light by transferring digitally gen- erated phase jumps from radio frequency (rf) electrical signals onto light by means of acousto-optic interaction. By tailoring the statistics of phase jumps in the electrical signal and thereby engineering the optical phase noise, we manipulate the visibil- ity of interference fringes in a Mach-Zehnder interferometer that incorporates two acousto-optic modulators. Such controlled dephasing finds applications in modern experiments involving the spread or diffusion of light in an optical network. Further, we analytically show how engineered partial phase noise can convert the dark port of a stabilised interferometer to a weak source of highly correlated photons.

  5. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics

    Science.gov (United States)

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C.; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F.; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E.; Dkhil, Brahim; Ruello, Pascal

    2016-01-01

    The ability to generate efficient giga–terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics. PMID:27492493

  6. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics.

    Science.gov (United States)

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E; Dkhil, Brahim; Ruello, Pascal

    2016-01-01

    The ability to generate efficient giga-terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics. PMID:27492493

  7. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics

    Science.gov (United States)

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C.; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F.; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E.; Dkhil, Brahim; Ruello, Pascal

    2016-08-01

    The ability to generate efficient giga-terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics.

  8. Quantum acousto-optic transducer for superconducting qubits

    CERN Document Server

    Shumeiko, V S

    2015-01-01

    We propose theory for reversible quantum transducer connecting superconducting qubits and optical photons using acoustic waves in piezoelectrics. The proposed device consists of integrated acousto-optic resonator that utilizes stimulated Brillouin scattering for phonon-photon conversion, and piezoelectric e?ect for coupling of phonons to qubits. We evaluate the phonon-photon coupling rate, and show that the required power of optical pump as well as the other device parameters providing full and faithful quantum conversion are feasible for implementation with the state of the art integrated acousto-optics.

  9. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    Science.gov (United States)

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-01

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions.

  10. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    Science.gov (United States)

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-01

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions. PMID:26561090

  11. Acousto-optic tuneable filters: advances and applications to microscopy

    Science.gov (United States)

    Pannell, C. N.; Wachman, E. S.; Farkas, D. L.; Ward, J.; Seale, W.

    2006-02-01

    The acousto-optic tunable filter (AOTF) is one example of a small number of commercially available optical filter technologies that lend themselves to imaging applications. In recent years the demand for high specification devices has increased significantly, and diffraction limited performance is being achieved.

  12. Dynamic fluorescence lifetime imaging based on acousto-optic deflectors

    Science.gov (United States)

    Yan, Wei; Peng, Xiao; Qi, Jing; Gao, Jian; Fan, Shunping; Wang, Qi; Qu, Junle; Niu, Hanben

    2014-11-01

    We report a dynamic fluorescence lifetime imaging (D-FLIM) system that is based on a pair of acousto-optic deflectors for the random regions of interest (ROI) study in the sample. The two-dimensional acousto-optic deflector devices are used to rapidly scan the femtosecond excitation laser beam across the sample, providing specific random access to the ROI. Our experimental results using standard fluorescent dyes in live cancer cells demonstrate that the D-FLIM system can dynamically monitor the changing process of the microenvironment in the ROI in live biological samples.

  13. Rigorous coupled wave analysis of acousto-optics with relativistic considerations.

    Science.gov (United States)

    Xia, Guoqiang; Zheng, Weijian; Lei, Zhenggang; Zhang, Ruolan

    2015-09-01

    A relativistic analysis of acousto-optics is presented, and a rigorous coupled wave analysis is generalized for the diffraction of the acousto-optical effect. An acoustic wave generates a grating with temporally and spatially modulated permittivity, hindering direct applications of the rigorous coupled wave analysis for the acousto-optical effect. In a reference frame which moves with the acoustic wave, the grating is static, the medium moves, and the coupled wave equations for the static grating may be derived. Floquet's theorem is then applied to cast these equations into an eigenproblem. Using a Lorentz transformation, the electromagnetic fields in the grating region are transformed to the lab frame where the medium is at rest, and relativistic Doppler frequency shifts are introduced into various diffraction orders. In the lab frame, the boundary conditions are considered and the diffraction efficiencies of various orders are determined. This method is rigorous and general, and the plane waves in the resulting expansion satisfy the dispersion relation of the medium and are propagation modes. Properties of various Bragg diffractions are results, rather than preconditions, of this method. Simulations of an acousto-optical tunable filter made by paratellurite, TeO(2), are given as examples. PMID:26367426

  14. A beamforming system based on the acousto-optic effect

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2012-01-01

    Beamforming techniques are usually based on microphone arrays. The present work uses a beam of light as a sensor element, and describes a beamforming system that locates sound sources based on the acousto-optic effect, this is, the interaction between sound and light. The use of light as a sensing...

  15. Acousto-plasmofluidics: Acoustic modulation of surface plasmon resonance in microfluidic systems

    Science.gov (United States)

    Ahmed, Daniel; Peng, Xiaolei; Ozcelik, Adem; Zheng, Yuebing; Huang, Tony Jun

    2015-09-01

    We acoustically modulated the localized surface plasmon resonances (LSPRs) of metal nanostructures integrated within microfluidic systems. An acoustically driven micromixing device based on bubble microstreaming quickly and homogeneously mixes multiple laminar flows of different refractive indices. The altered refractive index of the mixed fluids enables rapid modulation of the LSPRs of gold nanodisk arrays embedded within the microfluidic channel. The device features fast response for dynamic operation, and the refractive index within the channel is tailorable. With these unique features, our "acousto-plasmofluidic" device can be useful in applications such as optical switches, modulators, filters, biosensors, and lab-on-a-chip systems.

  16. Acousto-Optics Tunable Filter Based on a Hollow Optical Fiber for Broadband Polarization Switch Application

    Institute of Scientific and Technical Information of China (English)

    Jaewon; Lee; Jaewang; Yu; Sangsoo; Choi; Kyunghwan; Oh; Dong; Il; Yum; Byoung; Yoon; Kim

    2003-01-01

    A novel acousto-optic tunable filter (AOTF) using a hollow optical fiber (HOF) is proposed. Its broadband rejection over 100nm was observed and high polarization dependence as a polarization switch is discussed.

  17. Towards quantitative tissue absorption imaging by combining photoacoustics and acousto-optics

    CERN Document Server

    Daoudi, Khalid

    2012-01-01

    We propose a strategy for quantitative photoacoustic mapping of chromophore concentrations that can be performed purely experimentally. We exploit the possibility of acousto-optic modulation using focused ultrasound, and the principle that photons follow trajectories through a turbid medium in two directions with equal probability. A theory is presented that expresses the local absorption coefficient inside a medium in terms of noninvasively measured quantities and experimental parameters. Proof of the validity of the theory is given with Monte Carlo simulations.

  18. Electro-optic and acousto-optic laser beam scanners

    Science.gov (United States)

    Heberle, Johannes; Bechtold, Peter; Strauß, Johannes; Schmidt, Michael

    2016-03-01

    Electro-optical deflectors (EOD) and acousto-optical deflectors (AOD) are based on deflection of laser light within a solid state medium. As they do not contain any moving parts, they yield advantages compared to mechanical scanners which are conventionally used for laser beam deflection. Even for arbitrary scan paths high feed rates can be achieved. In this work the principles of operation and characteristic properties of EOD and AOD are presented. Additionally, a comparison to mirror based mechanical deflectors regarding deflection angles, speed and accuracy is made in terms of resolvable spots and the rate of resolvable spots. Especially, the latter one is up to one order of magnitude higher for EOD and AOD systems compared to conventional systems. Further characteristic properties such as response time, damage threshold, efficiency and beam distortions are discussed. Solid state laser beam deflectors are usually characterized by small deflection angles but high angular deflection velocities. As mechanical deflectors exhibit opposite properties an arrangement of a mechanical scanner combined with a solid state deflector provides a solution with the benefits of both systems. As ultrashort pulsed lasers with average power above 100 W and repetition rates in the MHz range have been available for several years this approach can be applied to fully exploit their capabilities. Thereby, pulse overlap can be reduced and by this means heat affected zones are prevented to provide proper processing results.

  19. Ultrasonic power measurement system based on acousto-optic interaction

    Science.gov (United States)

    He, Liping; Zhu, Fulong; Chen, Yanming; Duan, Ke; Lin, Xinxin; Pan, Yongjun; Tao, Jiaquan

    2016-05-01

    Ultrasonic waves are widely used, with applications including the medical, military, and chemical fields. However, there are currently no effective methods for ultrasonic power measurement. Previously, ultrasonic power measurement has been reliant on mechanical methods such as hydrophones and radiation force balances. This paper deals with ultrasonic power measurement based on an unconventional method: acousto-optic interaction. Compared with mechanical methods, the optical method has a greater ability to resist interference and also has reduced environmental requirements. Therefore, this paper begins with an experimental determination of the acoustic power in water contained in a glass tank using a set of optical devices. Because the light intensity of the diffraction image generated by acousto-optic interaction contains the required ultrasonic power information, specific software was written to extract the light intensity information from the image through a combination of filtering, binarization, contour extraction, and other image processing operations. The power value can then be obtained rapidly by processing the diffraction image using a computer. The results of this work show that the optical method offers advantages that include accuracy, speed, and a noncontact measurement method.

  20. Transformation of phase dislocations under acousto-optic interaction of optical and acoustical Bessel beams

    Science.gov (United States)

    Belyi, V. N.; Khilo, P. A.; Kazak, N. S.; Khilo, N. A.

    2016-07-01

    The generation of wavefront phase dislocations of vortex Bessel light beams under acousto-optic (AO) diffraction in uniaxial crystals has been investigated. For the first time the process of AO interaction is studied with participation of Bessel acoustic beams instead of plane waves. A mathematical description of AO interaction is provided, which supposes the satisfaction of two types of phase-matching condition. The acousto-optic processes of transferring optical singularities onto the wavefront of BLBs are investigated and the generation of high-order optical vortices is considered at the interaction of optical and acoustical Bessel beams. The change of Bessel function order or phase dislocation order is explained as a result of the spin–orbital interaction under acousto-optic diffraction of vortex Bessel beams.

  1. A DESIGN OF AN ACOUSTO-OPTICAL SPECTROMETER

    Directory of Open Access Journals (Sweden)

    G. Herrera-Martínez

    2009-01-01

    Full Text Available The radio spectroscopy has became a fundamental tool to study astronomical objets at the microwave band. Therefore, the design and construction of instruments with high spectral resolution, low power consumption and compact size for easy handle and transport are necessary. Here we present the design and the tests of an acousto-optical spectrometer for use in solar radio astronomy and for variability studies of cosmic masers sources with a 5 meter antenna (RT5 which is being reinstalled at the Sierra Negra site. We present the rst evaluations of the performance of the components and the laboratory assembly.

  2. Bulk and integrated acousto-optic spectrometers for radio astronomy

    Science.gov (United States)

    Chin, G.; Buhl, D.; Florez, J. M.

    1981-01-01

    The development of sensitive heterodyne receivers (front end) in the centimeter and millimeter range, and the construction of sensitive RF spectrometers (back end) enable the spectral lines of interstellar molecules to be detected and identified. A technique was developed which combines acoustic bending of a collimated coherent light beam by a Bragg cell followed by detection by a sensitive array of photodetectors (thus forming an RF acousto-optic spectrometer (AOS). An AOS has wide bandwidth, large number of channels, and high resolution, and is compact, lightweight, and energy efficient. The thrust of receiver development is towards high frequency heterodyne systems, particularly in the millimeter, submillimeter, far infrared, and 10 micron spectral ranges.

  3. Sound field reconstruction using acousto-optic tomography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2012-01-01

    When sound propagates through a medium, it results in pressure fluctuations that change the instantaneous density of the medium. Under such circumstances, the refractive index that characterizes the propagation of light is not constant, but influenced by the acoustic field. This kind of interaction...... the acousto-optic effect in air, and demonstrates that it can be measured with a laser Doppler vibrometer in the audible frequency range. The tomographic reconstruction is tested by means of computer simulations and measurements. The main features observed in the simulations are also recognized...

  4. Design of acousto-optical devices by topology optimization

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    2009-01-01

    the piezoelectric model is used in the optimization and the objective function is the squared absolute value of the strain in the vertical direction in the waveguide. The objective function is maximized by distributing air and solid material in an area below the waveguide. The optical model is solved...... with the squared applied electric power. It is here shown that the acousto-optical interaction can be increased almost 10 times by redistribution of solid material and air in the design domain....... by means of topology optimization is presented. The surface acoustic waves are generated by interdigital transducers in a 2D piezoelectric model, which is coupled to an optical model where the optical mode in the waveguide is found by solving the time-harmonic wave equation for the magnetic field. Only...

  5. Acousto-Optical/Electronic Processor For SAR

    Science.gov (United States)

    Bicknell, T. J.; Farr, W. H.

    1992-01-01

    Lightweight, compact, low-power apparatus processes synthetic-aperture-radar (SAR) returns in real time, providing imagery aboard moving aircraft or spacecraft platform. Processor includes optical and electronic subsystems that, together, resolve range and azimuth coordinates of radar targets by combination of spatial and temporal integrations.

  6. High Performance Acousto-Optic Arrays based on Fiber Bragg Gratings for Measuring Launch Acoustics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes to prove the feasibility of innovations in acousto-optic sensor development for measurement of launch...

  7. Collinear Acousto-Optical Transformation of Bessel Light Beams in Biaxial Gyrotropic Crystals

    Science.gov (United States)

    Belyi, V. N.; Kulak, G. V.; Krokh, G. V.; Shakin, O. V.

    2016-05-01

    The collinear acousto-optical transformation of Bessel light beams in biaxial gyrotropic crystals into two annular, internal conical refraction beams with orthogonal elliptical polarization is studied. It is found that the diffraction efficiency is maximal (~50-60%) for low ultrasound intensities and varies slightly with further increases in acoustic power. At high ultrasound intensities, the intensities of the transmitted and diffracted annular beams differ insignificantly. The possible use of this acousto-optical interaction for creating collinear tuneable narrow-band acousto-optical filters at low ultrasonic frequencies is demonstrated.

  8. Three-dimensional reconstruction of sound fields based on the acousto-optic effect

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Torras Rosell, Antoni

    2013-01-01

    The acousto-optic effect can be used to measure the pressure fluctuations in air created by acoustic disturbances (the propagation of light is affected by changes in the medium due to the presence of sound waves). This makes it possible to measure an arbitrary sound field using acousto-optic tomo......The acousto-optic effect can be used to measure the pressure fluctuations in air created by acoustic disturbances (the propagation of light is affected by changes in the medium due to the presence of sound waves). This makes it possible to measure an arbitrary sound field using acousto......-optic tomography via scanning the field with a laser Doppler vibrometer. Consequently, the spatial characteristics of the sound field are captured in the measurement, implicitly bearing the potential for a full holographic reconstruction in a three-dimensional space. Recent studies have examined the reconstruction...

  9. Suppression of Sidelobe for Acousto-Optic Tunable Filter in Near-Infrared Spectral Monitoring

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper we calculated the acoustic intensity distribution of different transducers, and designed acousto-optic tunable filter(AOTF) based on different transducers. Through the experiment, we find sidelobe can be reduced by changing the transducer geometry.

  10. Acousto-optic tunable filter as a notch filter

    Science.gov (United States)

    Gupta, Neelam

    2016-05-01

    An acousto-optic tunable filter (AOTF) is an all solid-state robust device with no-moving parts that has been used in the development of hyperspectral imagers from the ultraviolet to the longwave infrared. Such a device is developed by bonding a piezoelectric transducer on a specially cut prism in a birefringent crystal. When broadband white light is incident on the prism input facet, two orthogonally polarized diffracted beams at a wavelength with a narrowband bandpass are transmitted. The transmitted wavelength can be tuned by varying the applied radio frequency (RF). This is what is done in a hyperspectral imager. An AOTF can also be used with multiple RFs applied at the same time to diffract a number of different wavelengths. This mode can be exploited to design a tunable optical notch filter where multiple RFs are applied simultaneously such that all wavelength in a specific range can transmit except for a specific wavelength which is notched. We designed an optical system using a TeO2 AOTF with telecentric confocal optics operating in the shortwave infrared (SWIR) with a 16-channel RF driver where both the amplitude and frequency can be controlled independently for each channel. We will discuss the optical system, its characterization and present results obtained.

  11. Spectral characteristics of single-mode-fiber-based cascaded acousto-optic filters

    International Nuclear Information System (INIS)

    In this paper, two cascaded single-mode-fiber-based acousto-optic fiber grating schemes have been proposed and a comparative study on their spectral characteristics has been performed. By serially employing two acoustic transducers with the same geometrical and physical settings, a cascaded configuration of acousto-optic fiber gratings has been established. Experimental results indicate that the mode coupling efficiency has been improved due to the presence of the acoustic transducers in a serial configuration. Moreover, another cascaded acousto-optic tunable filter scheme is implemented based on a reflection configuration, in which an acousto-optic tunable filter is employed with a thin silver film coated at the fiber end as an efficient reflector for both of the core and cladding modes. And, moreover, spectral fringes resulting from the intermodal interference between the fundamental core mode and cladding modes have been experimentally observed, which is basically in accordance with our theoretical simulation result. Further theoretical investigation of its transmission spectral response to the acousto-optical coupling coefficient reveals the possibility to control the interference spectrum through adjusting the acousto-optic coupling strength of a single acoustic fiber grating, which is an important feature for the acoustic-grating-based fiber interferometers to be used in practical applications. (paper)

  12. Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors.

    Science.gov (United States)

    Salomé, R; Kremer, Y; Dieudonné, S; Léger, J-F; Krichevsky, O; Wyart, C; Chatenay, D; Bourdieu, L

    2006-06-30

    Two-photon scanning microscopy (TPSM) is a powerful tool for imaging deep inside living tissues with sub-cellular resolution. The temporal resolution of TPSM is however strongly limited by the galvanometric mirrors used to steer the laser beam. Fast physiological events can therefore only be followed by scanning repeatedly a single line within the field of view. Because acousto-optic deflectors (AODs) are non-mechanical devices, they allow access at any point within the field of view on a microsecond time scale and are therefore excellent candidates to improve the temporal resolution of TPSM. However, the use of AOD-based scanners with femtosecond pulses raises several technical difficulties. In this paper, we describe an all-digital TPSM setup based on two crossed AODs. It includes in particular an acousto-optic modulator (AOM) placed at 45 degrees with respect to the AODs to pre-compensate for the large spatial distortions of femtosecond pulses occurring in the AODs, in order to optimize the spatial resolution and the fluorescence excitation. Our setup allows recording from freely selectable point-of-interest at high speed (1kHz). By maximizing the time spent on points of interest, random-access TPSM (RA-TPSM) constitutes a promising method for multiunit recordings with millisecond resolution in biological tissues.

  13. A Tunable Acousto-Optic Fiber Filter Based on Two Simultaneous Mode Coupling Processes

    Institute of Scientific and Technical Information of China (English)

    MIAO Ren; ZHANG Wei; FENG Xue; ZHAO Jian-Hui; LIU Xiao-Ming

    2009-01-01

    A dynamically tunable fiber filter realizing complex spectra of phase-shifted long period fiber gratings (LPFGs)is proposed and demonstrated experimentally. The principle of the filter is based on two acousto-optic coupling processes occurring simultaneously. The first coupling process acts as a normal LPFG, while the second makes the coupling direction of the first process change continuously, leading to a similar transmission spectrum with the phase-shifted LPFGs, in which the changing of coupling direction is realized by the discrete phase shifts of the index modulation. By adjusting the acoustic drive signals, its transmission spectrum can be dynamically tuned to realize the phase-shifted LPFGs' spectra under different phase shift numbers and locations.

  14. Improving Acousto-Optical Interaction by Mechanical Resonators on a Surface

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    The finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with an optical wave in a waveguide. With a periodic model it is first shown that these electrodes act as a mechanical resonator, which introduces several confined...... types of surface acoustic waves compared to using a conventional interdigital transducer with thin electrodes. Thus, this indicates a way to improve acousto-optical interaction for integrated modulators.......The finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with an optical wave in a waveguide. With a periodic model it is first shown that these electrodes act as a mechanical resonator, which introduces several confined......-optical interaction with an optical wave in a waveguide. The difference in effective refractive index is calculated for the case where a positive and a negative electric potential, respectively, are applied to the electrode above the optical waveguide. This difference is increased more than 500 times using these new...

  15. Investigating the use of the acousto-optic effect for acoustic holography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Fernandez Grande, Efren; Jacobsen, Finn;

    2012-01-01

    Recent studies have demonstrated that the acousto-optic effect, that is, the interaction between sound and light, can be used as a means to visualize acoustic fields in the audible frequency range. The changes of density caused by sound waves propagating in air induce phase shifts to a laser beam...... that travels through the acoustic field. This phenomenon can in practice be captured with a laser Doppler vibrometer (LDV), and the pressure distribution of the acoustic field can be reconstructed using tomography. The present work investigates the potential of the acousto-optic effect in acoustic holography....... Two different holographic methods are examined for this purpose. One method first reconstructs the hologram plane using acousto-optic tomography and then propagates it using conventional near-field acoustic holography (NAH). The other method exploits the so-called Fourier Slice Theorem and bases all...

  16. Holographic reconstruction of sound fields based on the acousto-optic effect

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Torras Rosell, Antoni; Jacobsen, Finn

    2013-01-01

    Recent studies have shown that it is possible to measure a sound field using acousto-optic tomography. Theacousto-optic effect, i.e., the interaction between sound and light, can be used to measure an arbitrary soundfield by scanning it with a laser Doppler vibrometer (LDV) over an aperture...

  17. Improving surface acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    The acousto-optical interaction of an optical wave confined inside a waveguide and a surface acoustic wave launched by an interdigital transducer (IDT) at the surface of a piezoelectric material is considered. The IDT with high aspect ratio electrodes supports several acoustic modes...

  18. Spin-to-orbit conversion at acousto-optic diffraction of light: conservation of optical angular momentum.

    Science.gov (United States)

    Skab, Ihor; Vlokh, Rostyslav

    2012-04-01

    Acousto-optic diffraction of light in optically active cubic crystals is analyzed from the viewpoint of conservation of optical angular momentum. It is shown that the availability of angular momentum in the diffracted optical beam can be necessarily inferred from the requirements of angular momentum conservation law. As follows from our analysis, a circularly polarized diffracted wave should bear an orbital angular momentum. The efficiency of the spin-to-orbit momentum conversion is governed by the efficiency of acousto-optic diffraction.

  19. An investigation of sound fields based on the acousto-optic effect

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2011-01-01

    range, and in two different measurement scenarios where the sound field is well-known: in a rectangular duct and in an anechoic room. Models for predicting the acousto-optic effect in such scenarios are derived and measurements are carried out with a laser Doppler vibrometer. The results show a fairly...... field. This non-invasive technique is based on the so-called acousto-optic effect, i.e., the variations of the refractive index of a medium caused by density fluctuations, which follow sound pressure fluctuations. In the current study, this phenomenon is investigated in air, within the audible frequency...

  20. Optical transmission of single crystal tellurium for application in acousto-optic cells

    International Nuclear Information System (INIS)

    The optical properties of single crystals of tellurium (Te) are investigated in order to develop acousto-optic (AO) devices operating in the longwave infrared spectral region. The optical transparency of carefully cut and polished plates and large size samples of Te crystals was measured from 4 to 24 µm. The absorption of ordinary and extraordinary polarized optical beams was measured along various directions in the crystal with respect to the optic axis. Using a 10.6 µm CO2 laser the absorption coefficient for the best samples of Te was found to be 0.07 cm−1 for the ordinary and between 0.07 and 4.0 cm−1 for the extraordinary polarized optical beam. Here, we also discuss the possible application of Te crystals in fabricating AO imaging filters

  1. Improving acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    In recent years experiments have shown that optical waves in waveguides can be modulated by mechanical stresses from surface acoustic waves (SAW), which have most of their energy density concentrated at the surface. In these experiments the SAWs are generated in piezoelectric materials...

  2. Sub-optical wavelength acoustic wave modulation of integrated photonic resonators at microwave frequencies

    CERN Document Server

    Tadesse, Semere Ayalew

    2014-01-01

    Light-sound interactions have long been exploited in various acousto-optic devices based on bulk crystalline materials. Conventionally these devices operate in megahertz frequency range where the acoustic wavelength is much longer than the optical wavelength and a long interaction length is required to attain significant coupling. With nanoscale transducers, acoustic waves with sub-optical wavelengths can now be excited to induce strong acousto-optic coupling in nanophotonic devices. Here we demonstrate microwave frequency surface acoustic wave transducers co-integrated with nanophotonic resonators on piezoelectric aluminum nitride substrates. Acousto-optic modulation of the resonance modes at above 10 GHz with the acoustic wavelength significantly below the optical wavelength is achieved. The phase and modal matching conditions in this scheme are investigated for efficient modulation. The new acousto-optic platform can lead to novel optical devices based on nonlinear Brillouin processes and provides a direct...

  3. Guided-wave acousto-optics interactions, devices, and applications

    CERN Document Server

    1990-01-01

    The field of integrated- or guided-wave optics has experienced significant and continuous growth since its inception in the late 1960s. There has been a considerable increase in research and development activity in this field worldwide and some significant advances in the realization of working in­ tegrated optic devices and modules have been made in recent years. In fact, there have already been some commercial manufacturing and technical ap­ plications of such devices and modules. The guided-wave-acoustooptics involving Bragg interactions between guided optical waves and surface acoustic waves is one of the areas of in­ tegrated-optics that has reached some degree of scientific and technological maturity. This topical volume is devoted to an in-depth treatment of this emerging branch of science and technology. Presented in this volume are concise treatments on bulk-wave acoustooptics, guided-wave optics, and surface acoustic waves, and detailed studies of guided-wave acoustooptic Bragg diffraction in thr...

  4. Experimental research on the multi-order acousto-optic diffraction based on Raman-Nath diffraction

    Science.gov (United States)

    Gu, Huadong; Shao, Zhongxing; Zheng, Chenqi; Yang, Jie; Chen, Ruitao; Gu, Zetong

    2015-03-01

    In this paper, the experimental investigation on the interaction length for getting the optimum diffraction of the multi-order acousto-optic diffraction is presented. Based on these results, the feasibility of acousto-optic Q-switch taking H2O or TeO2 as medium respectively for ultraviolet and visible lasers are discussed. The fact that the optimum interaction length tightly relies on the frequency of the sound and does not relate to the wavelength and power of the light is found in the experiment. The interaction length will become longer as the frequency of the ultrasound becomes higher. The interaction length is about 8mm when the acoustic frequency is at about 9MHz and becomes about 4mm at 6MHz. A Q-switch that works with pure water is designed and a total diffractive efficiency of about 98% was obtained under the condition that the acoustic frequency is 9MHz and the acoustic power is 3.4W. An acousto-optic Q-switch made of TeO2, in terms of Raman-Nath diffraction is designed. With a cooling system on the device, a total diffractive efficiency of about 75% is obtained under the condition that the acoustic frequency is 10MHz and the acoustic power is 10W. The loss by one path of the device is about 5% on the best condition. Then the modulated pulse width is measured as about 200ns on the condition that the acoustic frequency is 11MHz, the acoustic power is 6W and the repetition frequency is 10kHz.

  5. Improving surface acousto-optical interaction by high aspect ratio electrodes

    OpenAIRE

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    The acousto-optical interaction of an optical wave confined inside a waveguide and a surface acoustic wave launched by an interdigital transducer (IDT) at the surface of a piezoelectric material is considered. The IDT with high aspect ratio electrodes supports several acoustic modes that are strongly confined to the surface, causing a significant increase in the strain underneath the surface. A finite element method is employed to model the surface acoustic waves generated by a finite length ...

  6. Analysis of the deviation of the diffracted beams caused by acousto-optic tunable filter in multispectral imaging

    Institute of Scientific and Technical Information of China (English)

    Yu Yang; Xuejun Sha; Zhonghua Zhang

    2011-01-01

    The deviation caused by acousto-optic tunable filter (AOTF) diffraction in multispectral imaging is analyzed through derivation calculus of the deviation angle. The rotatory polarization of acousto-optic crystal is taken into account in this analysis. The relationships between the polar angle of the incident and the diffracted beams are acquired by using the momentum-matching condition. During the diffraction of the incident beams, far more deviations are induced.%@@ The deviation caused by acousto-optic tunable filter(AOTF) diffraction in multispectral imaging is analyzed through derivation calculus of the deviation angle.The rotatory polarization of acousto-optic crystal is taken into account in this analysis.The relationships between the polar angle of the incident and the diffracted beams are acquired by using the momentum-matching condition.During the diffraction of the incident beams,far more deviations are induced.

  7. High repetition rate laser-induced breakdown spectroscopy using acousto-optically gated detection

    Science.gov (United States)

    Pořízka, Pavel; Klessen, Benjamin; Kaiser, Jozef; Gornushkin, Igor; Panne, Ulrich; Riedel, Jens

    2014-07-01

    This contribution introduces a new type of setup for fast sample analysis using laser-induced breakdown spectroscopy (LIBS). The novel design combines a high repetition rate laser (up to 50 kHz) as excitation source and an acousto-optical modulator (AOM) as a fast switch for temporally gating the detection of the emitted light. The plasma radiation is led through the active medium of the AOM where it is diffracted on the transient ultrasonic Bragg grid. The diffracted radiation is detected by a compact Czerny-Turner spectrometer equipped with a CCD line detector. Utilizing the new combination of high repetition rate lasers and AOM gated detection, rapid measurements with total integration times of only 10 ms resulted in a limit of detection (LOD) of 0.13 wt.% for magnesium in aluminum alloys. This short integration time corresponds to 100 analyses/s. Temporal gating of LIP radiation results in improved LODs and consecutively higher sensitivity of the LIBS setup. Therefore, an AOM could be beneficially utilized to temporally detect plasmas induced by high repetition rate lasers. The AOM in combination with miniaturized Czerny-Turner spectrometers equipped with CCD line detectors and small footprint diode pumped solid state lasers results in temporally gateable compact LIBS setups.

  8. Optical modulators with 2D layered materials

    Science.gov (United States)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  9. Power Analysis and Experimental Study of the Fiber Null Coupler with an Acousto-optic Device

    Institute of Scientific and Technical Information of China (English)

    WU Lei; ZHENG Yuan; QI Jiang; PU Hongtu; CHEN Shuqiang

    2002-01-01

    A single-mode fiber acousto-optic (AO) switch based on a null coupler at wavelength of 1.55 μm is reported.According to the coupled mode theory,power distribution of the null coupler with the acoustic-wave is formulated for general case.Excess loss of 0.1 dB and the schematic graph of throughput and coupled power are obtained experimentally.

  10. Depth discrimination in acousto-optic cerebral blood flow measurement simulation

    Science.gov (United States)

    Tsalach, A.; Schiffer, Z.; Ratner, E.; Breskin, I.; Zeitak, R.; Shechter, R.; Balberg, M.

    2016-03-01

    Monitoring cerebral blood flow (CBF) is crucial, as inadequate perfusion, even for relatively short periods of time, may lead to brain damage or even death. Thus, significant research efforts are directed at developing reliable monitoring tools that will enable continuous, bed side, simple and cost-effective monitoring of CBF. All existing non invasive bed side monitoring methods, which are mostly NIRS based, such as Laser Doppler or DCS, tend to underestimate CBF in adults, due to the indefinite effect of extra-cerebral tissues on the obtained signal. If those are to find place in day to day clinical practice, the contribution of extra-cerebral tissues must be eliminated and data from the depth (brain) should be extracted and discriminated. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133Xe SPECT and laser Doppler. We have assembled a comprehensive computerized simulation, modeling this acousto-optic technique in a highly scattering media. Using the combination of light and ultrasound, we show how depth information may be extracted, thus distinguishing between flow patterns taking place at different depths. Our algorithm, based on the analysis of light modulated by ultrasound, is presented and examined in a computerized simulation. Distinct depth discrimination ability is presented, suggesting that using such method one can effectively nullify the extra-cerebral tissues influence on the obtained signals, and specifically extract cerebral flow data.

  11. Pre-Juno Optical Analysis of Jupiter's Atmosphere with the NMSU Acousto-optic Imaging Camera

    Science.gov (United States)

    Dahl, Emma; Chanover, Nancy J.; Voelz, David; Kuehn, David M.; Strycker, Paul D.

    2016-10-01

    Jupiter's upper atmosphere is a highly dynamic system in which clouds and storms change color, shape, and size on variable timescales. The exact mechanism by which the deep atmosphere affects these changes in the uppermost cloud deck is still unknown. With Juno's arrival at Jupiter in July 2016, the thermal radiation from the deep atmosphere will be measurable with the spacecraft's Microwave Radiometer. By taking detailed optical measurements of Jupiter's uppermost cloud deck in conjunction with Juno's microwave observations, we can provide a context in which to better understand these observations. This data will also provide a complement to the near-IR sensitivity of the Jovian InfraRed Auroral Mapper and will expand on the limited spectral coverage of JunoCam. Ultimately, we can utilize the two complementary datasets in order to thoroughly characterize Jupiter's atmosphere in terms of its vertical cloud structure, color distribution, and dynamical state throughout the Juno era. In order to obtain high spectral resolution images of Jupiter's atmosphere in the optical regime, we use the New Mexico State University Acousto-optic Imaging Camera (NAIC). NAIC contains an acousto-optic tunable filter, which allows us to take hyperspectral image cubes of Jupiter from 450-950 nm at an average spectral resolution (λ/dλ) of 242. We present an analysis of our pre-Juno dataset obtained with NAIC at the Apache Point Observatory 3.5-m telescope during the night of March 28, 2016. Under primarily photometric conditions, we obtained 6 hyperspectral image cubes of Jupiter over the course of the night, totaling approximately 2,960 images. From these data we derive low-resolution optical spectra of the Great Red Spot and a representative belt and zone to compare with previous work and laboratory measurements of candidate chromophore materials. Future work will focus on radiative transfer modeling to elucidate the Jovian cloud structure during the Juno era. This work was supported

  12. Compact tunable microwave filter using retroreflective acousto-optic filtering and delay controls.

    Science.gov (United States)

    Riza, Nabeel A; Ghauri, Farzan N

    2007-03-01

    Programmable broadband rf filters are demonstrated using a compact retroreflective optical design with an acousto-optic tunable filter and a chirped fiber Bragg grating. This design enables fast 34 micros domain analog-mode control of rf filter time delays and weights. Two proof-of-concept filters are demonstrated including a two-tap notch filter with >35 dB notch depth and a four-tap bandpass filter. Both filters have 2-8 GHz tunability and a 34 micros reset time.

  13. Double pass in acousto-optic tunable filter for telecommunication network

    Science.gov (United States)

    Issa, Hadeel; Quintard, Véronique; Pérennou, André; Sakkour, Afif

    2014-07-01

    We investigate an acousto-optic tunable filter setup for wavelength division multiplexing telecommunication applications in wideband C (100 nm around 1550 nm). Anisotropic Bragg diffraction of light in TeO2 bulk crystal is first investigated experimentally and theoretically in a quasi-collinear interaction configuration. Based on those characterizations, we propose a double-pass optical beam which allows us to improve the filter performances in terms of crosstalk and selectivity: the full width at half maximum and the sidelobe level are reduced.

  14. Acousto-optic tunable filter for dispersion characterization of time-domain optical coherence tomography systems.

    Science.gov (United States)

    Chin, Catherine; Toadere, Florin; Feuchter, Thomas; Leick, Lasse; Moselund, Peter; Bradu, Adrian; Podoleanu, Adrian

    2016-07-20

    A broadband supercontinuum light source with an acousto-optic tunable filter (AOTF) are used to characterize dispersion in two time-domain OCT systems, at 850 and 1300 nm. The filter is designed to sweep across two spectral ranges, which are restricted here from 800 to 900 nm and from 1200 to 1500 nm, respectively. Dispersion compensation for 850 nm was achieved with a spectral delay line. Dispersion compensation for 1300 nm was achieved using BK 7 rod glasses in the reference arm. The AOTF allows evaluation of dispersion in under as well as overcompensated systems. The AOTF method is based on wavelength dependence of the optical path difference corresponding to the maximum strength of the interference signal recorded using a mirror as object. Comparison is made between the AOTF method and the more usual method based on measurement of the full width at half-maximum of the autocorrelation peak. This comparison shows that the AOTF method is more accurate in terms of evaluation of the dispersion left uncompensated after each adjustment. The AOTF method additionally provides information on the direction of dispersion compensation. PMID:27463927

  15. Contrast enhancement in microscopy of human thyroid tumors by means of acousto-optic adaptive spatial filtering

    Science.gov (United States)

    Yushkov, Konstantin B.; Molchanov, Vladimir Y.; Belousov, Pavel V.; Abrosimov, Aleksander Y.

    2016-01-01

    We report a method for edge enhancement in the images of transparent samples using analog image processing in coherent light. The experimental technique is based on adaptive spatial filtering with an acousto-optic tunable filter in a telecentric optical system. We demonstrate processing of microscopic images of unstained and stained histological sections of human thyroid tumor with improved contrast.

  16. Fourier transform acousto-optic imaging with a custom-designed CMOS smart-pixels array.

    Science.gov (United States)

    Barjean, Kinia; Contreras, Kevin; Laudereau, Jean-Baptiste; Tinet, Éric; Ettori, Dominique; Ramaz, François; Tualle, Jean-Michel

    2015-03-01

    We report acousto-optic imaging (AOI) into a scattering medium using a Fourier Transform (FT) analysis to achieve axial resolution. The measurement system was implemented using a CMOS smart-pixels sensor dedicated to the real-time analysis of speckle patterns. This first proof-of-principle of FT-AOI demonstrates some of its potential advantages, with a signal-to-noise ratio comparable to the one obtained without axial resolution, and with an acquisition rate compatible with a use on living biological tissue.

  17. AIMS: Acousto-optic imaging spectrometer for spectral mapping of solid surfaces

    Science.gov (United States)

    Glenar, David A.; Blaney, Diana L.; Hillman, John J.

    2003-01-01

    A compact, two-channel acousto-optic tunable filter (AOTF) camera is being built at GSFC as a candidate payload instrument for future Mars landers or small-body rendezvous missions. This effort is supported by the NASA Mars Instrument Development Program (MIDP), Office of Space Science Advanced Technologies and Mission Studies. Acousto-optic Imaging Spectrometer (AIMS) is electronically programmable and provides arbitrary spatial and spectral selection from 0.48 to 2.4 μm. The geometric throughput of AOTF's are well matched to the requirements for lander mounted cameras since (I) they can be made very compact, (II) "slow" (f/14-f/18) optics required for large depth-of-field fall well within the angular aperture limit of AOTF's, and (III) they operate at low ambient temperatures. A breadboard of the AIMS short-wavelength channel is now being used for spectral imaging of high-interest Mars analog materials (iron oxides, carbonates, sulfates and sedimentary basalts) as part of the initial instrument validation exercises.

  18. Mathematical Description of Acousto-Optic Tunable Filter Orthogonal Polarizing Method

    Institute of Scientific and Technical Information of China (English)

    XU Kexin; WEN Huizhi; ZHANG Hao; FAN Guofang; YANG Jisheng

    2005-01-01

    The transfer function of the optical splitting system of the acousto-optic tunable filter (AOTF) is deduced to be a reference to optical design. The characteristic matrix (transfer function) of AOTF is used to describe quantitatively the characters of polarization elements in the orthogonal polarizing system. According to the characteristic matrix, the included angle of polarizer's transmission direction and polarization analyzer's transmission direction should be 90°. As a result the signal to noise ratio increased about 20 times though the light intensity was reduced to 54.3% polarization analyzer are 0.74, which is an intrinsic character. The orthogonal polarizing method is an effective method to get rid of the influence of zero order light and improve the spectrum resolution and signal-to-noise ratio.

  19. Electro-mechanically induced GHz rate optical frequency modulation in silicon

    CERN Document Server

    Tallur, Siddharth

    2012-01-01

    We present a monolithic silicon acousto-optic frequency modulator (AOFM) operating at 1.09GHz. Direct spectroscopy of the modulated laser power shows asymmetric sidebands which indicate coincident amplitude modulation and frequency modulation. Employing mechanical levers to enhance displacement of the optical resonator resulted in greater than 67X improvement in the opto-mechanical frequency modulation factor over earlier reported numbers for silicon nanobeams.

  20. Experimental study of the use of multiband acousto-optic filters for spectral encoding / decoding the optical signals

    Science.gov (United States)

    Proklov, V. V.; Byshevski-Konopko, O. A.; Filatov, A. L.; Lugovskoi, A. V.; Pisarevsky, Yu V.

    2016-08-01

    A prototype of the acousto-optic (AO) decoder of optical signals is created on the base of the multiband AO filter. The joint work of the decoder with the developed previously AO coder has been verified experimentally. The main qualitative and quantitate characteristics of the spectral coding and decoding by Walsh sequences of the industrial LED radiation in the near infrared range are investigated. It is shown, that in the proposed data transmission system realization Signal-to-Interference Ratio (SIR) is not less than 13 dB.

  1. The Experimental Study on Wide-band Tunable All-fiber Acousto-optic Filter Based on Null Coupler

    Institute of Scientific and Technical Information of China (English)

    LI Tong; LI Qun; LIU Dan; LIU Xiaoming; PENG Jiangde

    2000-01-01

    The fiber acousto-optic filter is fabricated successfully for the first time in China. The mode conversion is realized by the acoustic-wave induced perturbation. Excess loss of 0.1 dB and continuous tuning range between 1470 nm and 1580 nm are obtained. The polarization dependence of the filter is studied experimentally.

  2. Spatial and temporal thermal analysis of acousto-optic deflectors using finite element analysis model.

    Science.gov (United States)

    Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun; Huang, Zhifeng; Zhou, Huaichun

    2012-07-01

    Thermal effects greatly influence the optical properties of the acousto-optic deflectors (AODs). Thermal analysis plays an important role in modern AOD design. However, the lack of an effective method of analysis limits the prediction in the thermal performance. In this paper, we propose a finite element analysis model to analyze the thermal effects of a TeO(2)-based AOD. Both transducer heating and acoustic absorption are considered as thermal sources. The anisotropy of sound propagation is taken into account for determining the acoustic absorption. Based on this model, a transient thermal analysis is employed using ANSYS software. The spatial temperature distributions in the crystal and the temperature changes over time are acquired. The simulation results are validated by experimental results. The effect of heat source and heat convection on temperature distribution is discussed. This numerical model and analytical method of thermal analysis would be helpful in the thermal design and practical applications of AODs.

  3. POLARIS-II - An acousto-optic imaging spectropolarimeter for ground-based astronomy

    Science.gov (United States)

    Glenar, D. A.; Hillman, J. J.; Saif, B.; Bergstralh, J.

    1992-01-01

    A compact, acousto-optic tunable filter (AOTF) imaging spectropolarimeter for ground based astronomy from 400-1100 nm has been constructed at NASA/GSFC. The key components of this instrument are a TeO2 non-collinear AOTF, CCD camera, and an all-reflective optical relay assembly which uses a single elliptical mirror to produce side-by-side orthogonally polarized spectral images. The instrument was used at the Lowell Observatory 42-inch telescope for 'first light' planetary imaging and measurements of photometric standard stars. Narrow-band images of Saturn near 700 nm appear to show polarization effects which result from multiple scattering by aerosols. The instrument has recently been upgraded in order to integrate the RF drive electronics and eliminate contamination by scattered light. Design of the instrument and some initial results are presented.

  4. Acousto-optic interaction in biconical tapered fibers: shaping of the stopbands

    Science.gov (United States)

    Ramírez-Meléndez, Gustavo; Bello-Jiménez, Miguel Ángel; Cuadrado-Laborde, Christian; Díez, Antonio; Cruz, José Luis; Rodríguez-Cobos, Amparo; Balderas-Navarro, Raúl; Andrés Bou, Miguel Vicente

    2016-03-01

    The effect of a gradual reduction of the fiber diameter on the acousto-optic (AO) interaction is reported. The experimental and theoretical study of the intermodal coupling induced by a flexural acoustic wave in a biconical tapered fiber shows that it is possible to shape the transmission spectrum, for example, substantially broadening the bandwidth of the resonant couplings. The geometry of the taper transitions can be regarded as an extra degree of freedom to design the AO devices. Optical bandwidths above 45 nm are reported in a tapered fiber with a gradual reduction of the fiber down to 70 μm diameter. The effect of including long taper transition is also reported in a double-tapered structure. A flat attenuation response is reported with 3-dB stopband bandwidth of 34 nm.

  5. Tapered acoustical directional couplers for integrated acousto-optical mode converters with weighted coupling

    Science.gov (United States)

    Herrmann, Harald; Rust, Ulrich; Schafer, Klaus

    1995-03-01

    Weighted coupling for strong sidelobe suppression of integrated acoustooptical mode converters in LiNbO3 using acoustical directional couplers has been studied theoretically and experimentally. A parameter free model for the propagation of surface acoustic waves in guiding structures has been developed based on a step-like variation of the acoustic velocity. Comparisons of theoretical results with experimental ones for acoustic waveguides and directional coupler structures confirm the applicability of the model. A coupled mode description of the acousto-optical polarization conversion in converters with acoustical directional couplers has been developed and applied to several tapered acoustical directional couplers. The model reveals that the conversion characteristics are usually strongly asymmetric. If the directional coupler is appropriately designed, a sidelobe suppression of about 30 dB can be achieved. First experimental results with tapered directional couplers confirm within some limits the theoretical predictions.

  6. Acousto-optic method used to control water pollution by miscible liquids

    Science.gov (United States)

    Ferria, Kouider; Griani, Lazhar; Laouar, Naamane

    2012-05-01

    An acousto-optic (A.O.) method has been developed for controlling the quality of water mixed by miscible liquids like acetone or ethanol… The liquid mixture is filled in a rectangular glass cell, which is placed orthogonally to the incident collimated beam of light. This cell consists of a piezoelectric transducer for generating ultrasonic waves. The collimated light while passing through this cell undergoes a diffraction phenomenon. The diffracted dots are collected by a converging photographic objective and displayed in its back focal plane. The location of the diffracted dots and their intensity are sensitive to any variation of the interaction medium. This result leads to decide about the quality of the water.

  7. High-dynamic-range hybrid analog-digital control broadband optical spectral processor using micromirror and acousto-optic devices.

    Science.gov (United States)

    Riza, Nabeel A; Reza, Syed Azer

    2008-06-01

    For the first time, to the best of our knowledge, the design and demonstration of a programmable spectral filtering processor is presented that simultaneously engages the power of an analog-mode optical device such as an acousto-optic tunable filter and a digital-mode optical device such as the digital micromirror device. The demonstrated processor allows a high 50 dB attenuation dynamic range across the chosen 1530-1565 nm (~C band). The hybrid analog-digital spectral control mechanism enables the processor to operate with greater versatility when compared to analog- or digital-only processor designs. Such a processor can be useful both as a test instrument in biomedical applications and as an equalizer in fiber communication networks.

  8. Optical modulators with two-dimensional layered materials

    CERN Document Server

    Sun, Zhipei; Wang, Feng

    2016-01-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that two-dimensional layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this review, we cover the state-of-the-art of optical modulators based on two-dimensional layered materials including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as two-dimensional heterostructures, plasmonic structures, and silicon/fibre integrated structures. We also take a look at future perspectives and discuss the potential of yet relatively unexplored mechanisms such as magneto-optic and acousto-optic modulation.

  9. An acousto-optical method for registration of erythrocytes' agglutination reaction—sera color influence on the resolving power

    Science.gov (United States)

    Doubrovski, V. A.; Medvedeva, M. F.; Torbin, S. O.

    2016-01-01

    The absorption spectra of agglutinating sera were used to determine blood groups. It was shown experimentally that the sera color significantly affects the resolving power of the acousto-optical method of blood typing. In order to increase the resolving power of the method and produce an invariance of the method for sera color, we suggested introducing a probing light beam individually for different sera. The proposed technique not only improves the resolving power of the method, but also reduces the risk of false interpretation of the experimental results and, hence, error in determining the blood group of the sample. The latter is especially important for the typing of blood samples with weak agglutination of erythrocytes. This study can be used in the development of an instrument for instrumental human blood group typing based on the acousto-optical method.

  10. Direct multi-channel optical spectrum analysis of radio-wave signals using collinear wave heterodyning in the single acousto-optical cell

    International Nuclear Information System (INIS)

    An attempt is made to improve the accuracy of a multi-channel parallel acousto-optical spectrum analysis through involving an additional nonlinear conversion into data processing. For this purpose we investigate the potential of exploiting a co-directional collinear wave heterodyning within an analysis of ultra-high-frequency radio-wave signals. The wave heterodyning under the proposal is performed via mixing the longitudinal elastic waves of finite amplitudes. It leads to a two-cascade processing in the single-crystalline cell and makes it possible to improve the relative frequency resolution of the acousto-optical spectrum analysis by an order of magnitude at the same frequency range. Both the theoretical findings and the corresponding estimations were used in proof-of-principle experiments directed at creating a new type of acousto-optical cell. The general concept of the proposed method and the basic conclusions are confirmed by experiments with the developed acousto-optic cell made of a lead molybdate crystal

  11. Optical modulator including grapene

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  12. Deflection of a monochromatic THz beam by acousto-optic methods

    Energy Technology Data Exchange (ETDEWEB)

    Voloshinov, V B; Nikitin, P A [Department of Physics, M.V. Lomonosov Moscow State University (Russian Federation); Gerasimov, V V; Choporova, Yu Yu [G.I. Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Knyazev, B A [Novosibirsk National Research State University, Novosibirsk (Russian Federation)

    2013-12-31

    The possibility of controlled deflection of an electromagnetic THz beam of a free-electron laser by acousto-optic (AO) methods has been demonstrated for the first time. The material of the AO deflector was chosen to be single-crystal germanium, which has a fairly large refractive index (n = 4.0) and a relatively low absorption coefficient for electromagnetic waves. The absorption coefficient α in germanium is 0.75 ± 0.02 cm{sup -1} at a wavelength λ = 140 μm. The diffracted beam intensity is shown to be maximum at an effective AO interaction length l = 1/α. A diffraction efficiency of 0.05% at a travelling acoustic wave power of 1.0 W is experimentally obtained. It is established that a change in the ultrasonic frequency from 25 to 39 MHz leads to variation in the external Bragg angle in the range from 19.5° to 27.5°. At a fixed Bragg angle θ{sub B} = 22.4° the frequency band of diffraction is 4.2 ± 0.1 MHz and the angular range of laser beam scanning reaches 2.5° ± 0.5°. The results obtained indicate that AO interaction can be used for controlled deflection of electromagnetic THz beams. (terahertz radiation)

  13. The ANTARES optical module

    International Nuclear Information System (INIS)

    The ANTARES collaboration is building a deep sea neutrino telescope in the Mediterranean Sea. This detector will cover a sensitive area of typically 0.1 km2 and will be equipped with about 1000 optical modules. Each of these optical modules consists of a large area photomultiplier and its associated electronics housed in a pressure resistant glass sphere. The design of the ANTARES optical module, which is a key element of the detector, has been finalized following extensive R and D studies and is reviewed here in detail

  14. Optical fibre gratings and their applications as acousto-optic devices

    OpenAIRE

    Liu, W. F

    1998-01-01

    1.1 Background Fibre optics has gained prominence in the fields of optical fibre communication, instrumentation, cable television and optical data networks. The major application however is in the area of the optical network where the availability of a wide variety of all-optical components is essential to the development of an all-optical network. Components based on optical fibres are extremely attractive due to their intrinsically low loss and compatibility with the fibre system. R...

  15. Multistage spectral polarimeter based on integrated acousto-optical Ti:LiNbO3 TE-TM converters for WDM system monitoring

    Science.gov (United States)

    Noe, Reinhold; Maucher, A.; Ricken, Raimund

    1999-04-01

    A 4-stage spectral polarimeter based on Ti:LiNbO3 acousto- optical TE-TM converters has been realized. It has about 20 dB stopband suppression and can measure polarimetric spectra as well as the time evolution of the state of polarization. A simple optical spectrum analyzer is also proposed.

  16. Kilohertz generation of high contrast polarization states for visible femtosecond pulses via phase-locked acousto-optic pulse shapers

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Hélène; Walsh, Brenna; Palato, Samuel; Kambhampati, Patanjali, E-mail: pat.kambhampati@mcgill.ca [Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8 (Canada); Thai, Alexandre; Forget, Nicolas [Fastlite, 1900 route des Crêtes, 06560 Valbonne (France); Crozatier, Vincent [Fastlite, Centre Scientifique d' Orsay, Bât.503, Plateau du Moulon, BP 45 Orsay (France)

    2015-09-14

    We present a detailed analysis of a setup capable of arbitrary amplitude, phase, and polarization shaping of broadband visible femtosecond pulses at 1 kHz via a pair of actively phase stabilized acousto-optic programmable dispersive filters arranged in a Mach-Zehnder interferometer geometry. The setup features phase stability values around λ/225 at 580 nm as well as degrees of polarization of at least 0.9 for any polarization state. Both numbers are important metrics to evaluate a setup's potential for applications based on polarization-shaped femtosecond pulses, such as fully coherent multi-dimensional electronic spectroscopy.

  17. Kilohertz generation of high contrast polarization states for visible femtosecond pulses via phase-locked acousto-optic pulse shapers

    International Nuclear Information System (INIS)

    We present a detailed analysis of a setup capable of arbitrary amplitude, phase, and polarization shaping of broadband visible femtosecond pulses at 1 kHz via a pair of actively phase stabilized acousto-optic programmable dispersive filters arranged in a Mach-Zehnder interferometer geometry. The setup features phase stability values around λ/225 at 580 nm as well as degrees of polarization of at least 0.9 for any polarization state. Both numbers are important metrics to evaluate a setup's potential for applications based on polarization-shaped femtosecond pulses, such as fully coherent multi-dimensional electronic spectroscopy

  18. A high-speed automatic spectrometer based on a solid-state non-collinear acousto-optic tunable filter

    Institute of Scientific and Technical Information of China (English)

    Jianhua Zhu(朱建华); Andrew Y.S.Cheng(郑玉臣)

    2003-01-01

    An automatic visible spectrometer based on a non-collinear acousto-optic tunable filter (AOTF) isconstructed for high-speed spectrometry. Its spectral filtering characteristics, such as relationshipsbetween the radio-frequency (RF) driving frequency and the output central wavelength, the outputbandwidth and the central wavelength, its typical spectral point spread function (PSF), and so on, arestudied systematically. The preliminary measurement results of AOTF spectrometer show that it is asolid-state, high-speed, easily controllable by computer-programming, rugged and compact spectroscopicdevice in comparison with a conventional grating spectrometer, and has the potential for widespreadspectrometric applications.

  19. Integrated acousto-optic polarization converter in a ZX-cut LiNbO(3) waveguide superlattice.

    Science.gov (United States)

    Yudistira, D; Janner, D; Benchabane, S; Pruneri, V

    2009-10-15

    We report an integrated acousto-optic polarization converter exploiting a novel surface acoustic superlattice (S-ASL) transducer. The S-ASL transducer is made of a ZX-cut periodically poled lithium niobate (PPLN) crystal with uniform coplanar electrodes for surface acoustic wave (SAW) generation. For a PPLN period of 20 microm the SAW is excited at an rf of about 190 MHz, while the phase matching occurs at an optical wavelength of around 1456 nm. The measured mode conversion efficiency of 90% at an input rf power of 1 W and the 3 dB optical bandwidth of 2.5 nm confirm the confinement of the SAW between the electrode gap and the constructive interaction along the whole 10 mm electrode length. PMID:19838274

  20. Information encryption and retrieval in mid-RF range using acousto-optic chaos

    Science.gov (United States)

    Chatterjee, Monish R.; Kundur, Abhinay

    2012-06-01

    In recent work, low-frequency AC signal encryption, decryption and retrieval using system-parameter based keys at the receiver stage of an acousto-optic (A-O) Bragg cell under first-order feedback have been demonstrated [1,2]. The corresponding nonlinear dynamics have also been investigated using the Lyapunov exponent and the so-called bifurcation maps [3]. The results were essentially restricted to A-O chaos around 10 KHz, and (baseband) signal bandwidths in the 1-4 KHz range. The results have generally been satisfactory, and parameter tolerances (prior to severe signal distortion at the output) in the +/-5% - +/-10% range have been obtained. Periodic AC waveforms, and a short audio clip have been examined in this series of investigations. Obviously, a main drawback in the above series of simulations has been the low and impractical signal bandwidths used. The effort to increase the bandwidth involves designing a feedback system with much higher chaos frequency that would then be amenable to higher BW information. In this paper, we re-visit the problem for the case where the feedback delay time is reduced considerably, and the system parameters in the transmitter adjusted in order to drive the system with a DC driver bias into chaos. Reducing the feedback time delay to less than 1 μs, an average chaos frequency of about 10 MHz was achieved after a few trials. For the AC application, a chaos region was chosen that would allow a large enough dynamic range for the width of the available passband. Based on these dynamic choices, periodic AC signals with 1 MHz (fundamental) bandwidth were used for the RF bias driver (along with a DC bias). A triangular wave and a rectangular pulse train were chosen as examples. Results for these cases are presented here, along with comments on the system performance, and the possibility of including (static) images for signal encryption. Overall, the results are encouraging, and affirm the possibility of using A-O chaos for securely

  1. Femtosecond THz time domain spectroscopy at 36 kHz scan rate using an acousto-optic delay

    CERN Document Server

    Urbanek, B; Eisele, M; Baierl, S; Kaplan, D; Lange, C; Huber, R

    2016-01-01

    We present a rapid-scan, time-domain terahertz spectrometer employing femtosecond Er:fiber technology and an acousto-optic delay with attosecond precision, enabling scanning of terahertz transients over a 12.4 ps time window at a waveform refresh rate of 36 kHz, and a signal-to-noise ratio of $1.7 \\times 10^5/\\sqrt{\\rm Hz}$. Our approach enables real-time monitoring of dynamic THz processes at unprecedented speeds, which we demonstrate through rapid 2D thickness mapping of a spinning teflon disc at a precision of $10\\,\\rm nm/\\sqrt{\\rm Hz}$. The compact, all-optical design ensures alignment-free operation even in harsh environments.

  2. Femtosecond terahertz time-domain spectroscopy at 36 kHz scan rate using an acousto-optic delay

    Science.gov (United States)

    Urbanek, B.; Möller, M.; Eisele, M.; Baierl, S.; Kaplan, D.; Lange, C.; Huber, R.

    2016-03-01

    We present a rapid-scan, time-domain terahertz spectrometer employing femtosecond Er:fiber technology and an acousto-optic delay with attosecond precision, enabling scanning of terahertz transients over a 12.4-ps time window at a waveform refresh rate of 36 kHz, and a signal-to-noise ratio of 1.7 × 105 / √{ H z } . Our approach enables real-time monitoring of dynamic THz processes at unprecedented speeds, which we demonstrate through rapid 2D thickness mapping of a spinning teflon disc at a precision of 10 nm/ √{ H z } . The compact, all-optical design ensures alignment-free operation even in harsh environments.

  3. Analysis of line broadening and spectral asymmetry in an all-fiber torsional acousto-optic band-pass filter

    International Nuclear Information System (INIS)

    The transmission properties of an all-fiber torsional acousto-optic (AO) band-pass filter with a sub-nm bandwidth is studied. The device is based on torsional AO coupling in a highly birefringent (HB) optical fiber. The full width at half maximum (FWHM) measured in a conventional band (C-band) is 0.88 nm, which is compared with the theoretical value of 0.45 nm estimated by using the coupled mode theory. The line broadening and the spectral asymmetry observed in experiments are investigated in detail through our theoretical model and full numerical analyses. The influence of the non-uniformity in the birefringence of the HB fiber on the filter's transmission is analyzed quantitatively in terms of the change in the filtering bandwidth, the sidelobe asymmetry, and the resonance shift.

  4. Characterization of the optical sub-system in an advanced prototype of a new acousto-optical spectrometer for the Mexican Large Millimeter Telescope

    Science.gov (United States)

    Shcherbakov, Alexandre S.; Sanchez Lucero, Daniel; Laskin, Alexander

    2011-09-01

    A few optically matched by each other sub-systems related to an advanced prototype of acousto-optical spectrometer for radio-astronomy are analyzed jointly. Rather precise control over the incident light polarization should be assured in the scheme together with a required expanding of the incident light beam. Moreover, the needed light-beam apodization, suppressing side lobes within registration of each individual resolvable spot and increasing the dynamic range of spectrometer, has to be taken into account as well. The current stage of analysis related to afore-mentioned problems as well as the results of trial experiments are presented.

  5. The effect of input phase modulation to a phase-sensitive optical amplifier

    CERN Document Server

    Li, Tian; Horrom, Travis; Jones, Kevin M; Lett, Paul D

    2016-01-01

    Many optical applications depend on amplitude modulating optical beams using devices such as acousto-optical modulators (AOMs) or optical choppers. Methods to add amplitude modulation (AM) often inadvertently impart phase modulation (PM) onto the light as well. While this PM is of no consequence to many phase-insensitive applications, phase-sensitive processes can be affected. Here we study the effects of input phase and amplitude modulation on the output of a quantum-noise limited phase-sensitive optical amplifier (PSA) realized in hot $^{85}$Rb vapor. We investigate the dependence of PM on AOM alignment and demonstrate a novel approach to quantifying PM by using the PSA as a diagnostic tool. We then use this method to measure the alignment-dependent PM of an optical chopper which arises due to diffraction effects as the chopper blade passes through the optical beam.

  6. 基于绝缘体上硅的一种改进的Mach-Zehnder声光调制器∗%An improved Mach-Zehnder acousto-optic mo dulator on a silicon-on-insulator platform

    Institute of Scientific and Technical Information of China (English)

    秦晨; 余辉; 叶乔波; 卫欢; 江晓清

    2016-01-01

    The interdigital transducer (IDT) of the traditional Mach-Zehnder (MZ) acousto-optic modulator on a silicon-on-insulator (SOI) platform is located outside its two arms. The crest and trough of the surface acoustic wave (SAW) are used to modulate the two arms of the MZ interferometer so as to achieve a high modulation efficiency. Therefore, the distance between the two arms must be odd multiples of half acoustic wavelength. However, since the substrate is usually not uniform, the wavelength of the SAW changes as it transmits through the surface of the device. As a result, the exact distance between the two arms is difficult to choose. On the other hand, the SAW losses a portion of energy after passing through the first arm of the MZ interferometer, so the modulation of the second arm becomes much weaker. To solve these problems, we propose a new structure where its IDT is situated in the middle of the two arms of the MZ interferometer. With this scheme, the two arms of the MZ interferometer are located exactly at the crest and the trough of the SAW, while they are modulated with equal strength. In this paper, we first use the finite element method to simulate the acoustic frequency and the surface displacement of the excited SAW. Then we deduce the refractive index variations of all layers according to their acousto-optic effects. After that, we analyze the influences of different factors on the acousto-optic modulation efficiency, including the type and size of waveguide, the thickness of zinc oxide (ZnO) layer, and the area it covers, the number of electrodes, etc. These parameters are accordingly optimized to enhance the modulation efficiency. Modeling result based on COMSOL Multiphysics indicates that when the width of the strip waveguide is 6 µm, the ZnO layer covers only the area under the IDT and has a thickness of 2.2 µm, and the number of the electrodes is 50, the effective refractive index variation of the waveguide reaches 4.08 × 10−4 provided that

  7. Pure electrical, highly-efficient and sidelobe free coherent Raman spectroscopy using acousto-optics tunable filter (AOTF)

    Science.gov (United States)

    Meng, Zhaokai; Petrov, Georgi I.; Yakovlev, Vladislav V.

    2016-02-01

    Fast and sensitive Raman spectroscopy measurements are imperative for a large number of applications in biomedical imaging, remote sensing and material characterization. Stimulated Raman spectroscopy offers a substantial improvement in the signal-to-noise ratio but is often limited to a discrete number of wavelengths. In this report, by introducing an electronically-tunable acousto-optical filter as a wavelength selector, a novel approach to a broadband stimulated Raman spectroscopy is demonstrated. The corresponding Raman shift covers the spectral range from 600 cm-1 to 4500 cm-1, sufficient for probing most vibrational Raman transitions. We validated the use of the new instrumentation to both coherent anti-Stokes scattering (CARS) and stimulated Raman scattering (SRS) spectroscopies.

  8. Narrow linewidth broadband tunable semiconductor laser at 840 nm with dual acousto-optic tunable configuration for OCT applications

    Science.gov (United States)

    Chamorovskiy, Alexander; Shramenko, Mikhail V.; Lobintsov, Andrei A.; Yakubovich, Sergei D.

    2016-03-01

    We demonstrate a tunable narrow linewidth semiconductor laser for the 840 nm spectral range. The laser has a linear cavity comprised of polarization maintaining (PM) fiber. A broadband semiconductor optical amplifier (SOA) in in-line fiber-coupled configuration acts as a gain element. It is based on InGaAs quantum-well (QW) active layer. SOA allows for tuning bandwidth exceeding 25 nm around 840 nm. Small-signal fiber-to-fiber gain of SOA is around 30 dB. A pair of acousto-optic tunable filters (AOTF) with a quasi-collinear interaction of optical and acoustic waves are utilized as spectrally selective elements. AOTF technology benefits in continuous tuning, broadband operation, excellent reproducibility and stability of the signal, as well as a high accuracy of wavelength selectivity due to the absence of mechanically moving components. A single AOTF configuration has typical linewidth in 0.05-0.15 nm range due to a frequency shift obtained during each roundtrip. A sequential AOTF arrangement enables instantaneous linewidth generation of power is in the range of 1 mW. While the majority of commercial tunable sources operate in 1060-1550 nm spectral ranges, the 840 nm spectral range is beneficial for optical coherence tomography (OCT). The developed narrow linewidth laser can be relevant for OCT with extended imaging depth, as well as spectroscopy, non-destructive testing and other applications.

  9. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    Science.gov (United States)

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-01

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to -0.70 nm within the spectral range of 500-850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  10. Bit error rate optimization of an acousto-optic tracking system for free-space laser communications

    Science.gov (United States)

    Sofka, J.; Nikulin, V.

    2006-02-01

    Optical communications systems have been gaining momentum with the increasing demand for transmission bandwidth in the last several years. Optical cable based solutions have become an attractive alternative to copper based system in the most bandwidth demanding applications due to increased bandwidth and longer inter-repeater distances. The promise of similar benefits over radio communications systems is driving the research into free space laser communications. Along with increased communications bandwidth, a free space laser communications system offers lower power consumption and the possibility for covert data links due to the concentration of the energy of the laser into a narrow beam. A narrow beam, however, results in a requirement for much more accurate and agile steering, so that a data link can be maintained in a scenario of communication platforms in relative motion or in the presence of vibrations. This paper presents a laser beam tracking system employing an acousto-optic cell capable of deflecting a laser beam at a very high rate (order of tens of kHz). The tracking system is subjected to vibrations to simulate a realistic implementation, resulting in the increase of BER. The performance of the system can be significantly improved through digital control. A constant gain controller is complemented by a Kalman filter the parameters of which are optimized to achieve the lowest possible BER for a given vibrations spectrum.

  11. Multilevel Modulation formats for Optical Communication

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee

    2008-01-01

    This thesis studies the use of multilevel modulation formats for optical communication systems. Multilevel modulation is an attractive method of increasing the spectral efficiency of optical communication systems. Various modulation formats employing phase modulation, amplitude modulation...

  12. Narrow linewidth broadband tunable semiconductor laser at 840 nm with dual acousto-optic tunable configuration for OCT applications

    Science.gov (United States)

    Chamorovskiy, Alexander; Shramenko, Mikhail V.; Lobintsov, Andrei A.; Yakubovich, Sergei D.

    2016-03-01

    We demonstrate a tunable narrow linewidth semiconductor laser for the 840 nm spectral range. The laser has a linear cavity comprised of polarization maintaining (PM) fiber. A broadband semiconductor optical amplifier (SOA) in in-line fiber-coupled configuration acts as a gain element. It is based on InGaAs quantum-well (QW) active layer. SOA allows for tuning bandwidth exceeding 25 nm around 840 nm. Small-signal fiber-to-fiber gain of SOA is around 30 dB. A pair of acousto-optic tunable filters (AOTF) with a quasi-collinear interaction of optical and acoustic waves are utilized as spectrally selective elements. AOTF technology benefits in continuous tuning, broadband operation, excellent reproducibility and stability of the signal, as well as a high accuracy of wavelength selectivity due to the absence of mechanically moving components. A single AOTF configuration has typical linewidth in 0.05-0.15 nm range due to a frequency shift obtained during each roundtrip. A sequential AOTF arrangement enables instantaneous linewidth generation of <0.01 nm by compensating for this shift. Linewidth as narrow as 0.0036 nm is observed at 846 nm wavelength using a scanning Fabry-Perot interferometer with 50 MHz spectral resolution. Output power is in the range of 1 mW. While the majority of commercial tunable sources operate in 1060-1550 nm spectral ranges, the 840 nm spectral range is beneficial for optical coherence tomography (OCT). The developed narrow linewidth laser can be relevant for OCT with extended imaging depth, as well as spectroscopy, non-destructive testing and other applications.

  13. Characterization of the non-collinear acousto-optical cell based on calomel (Hg2Cl2) crystal and operating within the two-phonon light scattering

    Science.gov (United States)

    Shcherbakov, Alexandre S.; Arellanes, Adan O.

    2016-03-01

    Performances of any system for data processing based on acousto-optical technique are mainly determined by parameters of the acousto-optical cell (AOC) exploited within the schematic arrangement. Here, basic properties of the AOC, involved into a novel processor for precise optical spectrum analysis dedicated to modern astrophysical applications, are considered. Because potential applications of this processor will be focused on investigations in extra-galactic astronomy as well as studies of extra-solar planets, an advanced regime of the non-collinear two-phonon light scattering has been elaborated for spectrum analysis with significantly improved spectral resolution. Under similar uprated requirements, the AOC, based on that specific regime in the calomel (Hg2Cl2) crystal, had been chosen, and its parameters were analyzed theoretically and verified experimentally. Then, the adequate approach to estimating the frequency/spectral bandwidth and spectral resolution had been developed. The bandwidth was calculated and experimentally realized with the additionally involved tilt angle of light incidence, allowing variations for acoustic frequencies. The resolution was characterized taking into account its doubling peculiar to the nonlinear two-phonon mechanism of light scattering. Proof-of-principle experiments were performed with the calomel AOC of 52 mm optical aperture, providing ~94% efficiency in the transmitted light due to the slow-shear acoustic mode of finite amplitude (the acoustic power density ~150 mW/mm2) with the velocity of 0.347×105 cm/s at the radio-wave acoustic frequency ~71 MHz. As a result, we have obtained the spectral resolution <0.235 Å within the spectral bandwidth <290 Å that looks as the best one can mention at the moment in acousto-optics.

  14. Improving the acousto-optical interaction in a Mach-Zehnder interferometer

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole

    2009-01-01

    of a piezoelectric, inhomogeneous material, and reflections from the boundaries are avoided by applying perfectly matched layers. The optical modes in the waveguides are modeled by time-harmonic wave equations for the magnetic field. The two models are coupled using stress-optical relations and the change...

  15. 基于偏振模式转换的声光陀螺研究%Research of Acousto-Optical Gyroscope Based on Polarization-Mode Conversion

    Institute of Scientific and Technical Information of China (English)

    路书祥; 陈淑芬; 付雷; 邹正锋; 孟彦彬

    2012-01-01

    A type of acousto-optic gyroscope based on polarization-mode conversion is presented, the principle and structure is analyzed and some tests of the gyroscope are carried out. The sensitivity of sensor is also given. The statical result shows that the coupling efficient is 80.02% when the length of acousto-optic interaction is 15 mm, the input electrical power of surface acoustic wave (SAW) is 100 mW and the frequency of SAW is 168. 201 MHz. A linear voltage-rotation response curve of the gyroscope is obtained when rotating, and the sensitivity is 1 mV/[C)/s]. Acousto-optic gyroscope based on polarization-mode conversion keeps the advantage of SAW gyroscope, and the sensitivity is enhanced greatly.%提出一种基于偏振模式转换的声光陀螺,分析其原理与结构并对该陀螺进行实验测试.静态测试结果表明,当声光作用长度为15 mm,声表面波输入功率为100 mW,频率为168.201 MHz时,偏振模式转化效率为80.02%.在偏置条件下进行旋转测试,得到输出电压随陀螺转速呈线性变化的曲线,其灵敏度约为1 mY/[(°)/s].偏振型声光陀螺保留声表面波陀螺体积小、成本低等优点,而在灵敏度上有大幅提高.

  16. LD end-pumped acousto-optic Q-switched 1319 nm/1338 nm dual-wavelength Nd:YAG laser

    Science.gov (United States)

    Wu, C. T.; Yu, M.; Wang, C.; Yu, K.; Yu, Y. J.; Chen, X. Y.; Jin, G. Y.

    2016-10-01

    Laser characteristics of acousto-optic Q-switched operation of 1319 nm/1338 nm dual-wavelength composite Nd:YAG laser were studied. Maximum output power of 5.77 W was achieved in CW operation. Under Q-switched operation, the maximum peak power of 3.96 kW and minimum pulse width of 65.6 ns was obtained at repetition frequency of 20 kHz with the duty ratio of 96%. The influence of the duration of the ultrasonic field acted on the Q-switch to the output characteristics of dual-wavelength composite Nd:YAG laser had been reported first time.

  17. Three-dimensional acousto-optic mapping using planar scanning with ultrasound bursts

    NARCIS (Netherlands)

    Bratchenia, A.; Molenaar, R.; Kooyman, R.P.H.; Oraevsky, Alexander; Wang, Lihong V.

    2009-01-01

    We have investigated the application of AO sensing for quantitative three-dimensional mapping of tissue-mimicking phantoms. An Intralipid phantom, which contains a turbid absorber, confined in a silicone tube, was used. Multiply scattered pulsed laser light was modulated by ultrasonic bursts focused

  18. Acousto-optical detection of hidden objects via speckle based imaging.

    Science.gov (United States)

    Lev, Aner; Sfez, Bruno

    2015-10-01

    Optical detection of objects hidden behind opaque screening layers is a challenging problem. We demonstrate an optically detected echographic-like method that combines collimated acoustic and laser beams. The acoustic waves cross the screening layers, and their back-reflection from the hidden objects is detected through the analysis of a dynamic laser speckle pattern created at the outer surface of the screening layer. Real-time remote detection of moving targets 15 meters away, with a few mm resolution is demonstrated using a very sensitive camera detection scheme. PMID:26480159

  19. Simulation of acousto-optical interaction in a Mach-Zehnder interferometer

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole; Jensen, Jakob Søndergaard

    of half the SAW wavelength the light at the output waveguide will interfere constructively and destructively in a periodic way and the MZI can hence be used as an optical switch. To understand and improve the interaction of the elastic field from the SAW with the optical field in the waveguides...... a numerical model of the MZI is constructed. The generation of the SAW by interdigital transducers is studied using a 2D finite element model of a piezoelectric, anisotropic material implemented in the high-level programming language Comsol Multiphysics. By calculating the stresses in the waveguide arms...

  20. 基于光纤叠栅的全光纤声光可调谐滤波器的特性分析∗%Analysis of all fib er acousto-optic tunable filter based on sup erimp osed fib er Bragg gratings

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    In this paper, an all fiber acousto-optic tunable filter based on superimposed fiber Bragg gratings (SFBG-AOTF) is demonstrated and studied. Compared to the normal fiber Bragg gratings based all fiber acousto-optic tunable filter, SFBG-AOTF can modulate the two optical resonant wavelengths of the gratings synchronously. The spectrum of SFBG-AOTF at various acoustic frequencies and under acoustically induced strains, has been analyzed theoretically. Based on simulation results, one can find that each order of the secondary reflection peak is symmetrical with respect to the two primary reflection peaks with SFBG as the center, and the resonant wavelength spacing between the primary reflection peak and the secondary reflection peak which is modulated by the former, is proportional to the acoustic frequency. But the resonant wavelength between the same order secondary reflection peaks which are modulated by two different primary reflection peaks, is independent of the acoustic frequency. The acoustically induced strains mainly affect the variation of the reflectivities of the primary and secondary reflection peaks. In the experiment, the spectra of SFBG-AOTF with acoustic frequencies of 390 and 710 kHz, are measured. The variation trend of the experimental results accords well with the simulated one.

  1. Optical Electronics. Electronics Module 9. Instructor's Guide.

    Science.gov (United States)

    Franken, Bill

    This module is the ninth of 10 modules in the competency-based electronics series. Introductory materials include a listing of competencies addressed in the module, a parts/equipment list, and a cross reference table of instructional materials. Five instructional units cover: fiber optic cable; optical coupler; lasers and masers; optical displays;…

  2. High Power Continuous-Wave and Acousto-Optic Q-Switched Nd:GdVO4 Laser Operated at 912 nm

    Institute of Scientific and Technical Information of China (English)

    GAO Jing; Yu Xin; CHEN Fei; LI Xu-Dong; ZHANG Zhen; YU Jun-Hua; WANG Yue-Zhu

    2008-01-01

    We present a high power and efficient operation of the 4F3/2→4I9/2transition in Nd:GdVO4 at 912 nm.In the cw mode,the maximum output power of 8.6 W is achieved when the incident pump power is 40.3W,leading to a slope efficiency of 33.3%and an optical-optical efficiency of 21.3%.To the best of our knowledge,this is the highest cw laser power at 912nm obtained with the conventional Nd:GdVO4 crystal.Pulsed operation of 912 nm laser has also been realized by inserting a small acousto-optic (A-O)Q-Switch inside the resonator.As a result,the minimal pulse width of 20ns and the average laser power 1.43 W at the repetition rate of 10kHz are obtained,corresponding to 7.1 kW peak power.We believe that this is the highest laser peak power at 912 nm.Furthermore.duration of 65 ns has also been acquired when the repetition rate is 100 kHz.

  3. The visible to the near infrared narrow band acousto-optic tunable filter and the hyperspectral microscopic imaging on biomedicine study

    International Nuclear Information System (INIS)

    Based on the parallel tangents momentum-matching condition, a narrow band noncollinear acousto-optic tunable filter (AOTF) using a single TeO2 crystal is designed with the consideration of the birefringence and the rotatory property of the material. An effective setup is established to evaluate the performance of the designed AOTF. The experimental observed spectrum pattern of the diffracted light is nearly the same with the theoretical result. The measured tuning relationship between the diffracted central optical wavelength and acoustic frequency is in accordance with the theoretical prospect. The optical bandwidth of the diffracted light is as narrow as 1.88 nm when the central wavelength is 556.75 nm. The high spectral resolution is significant in practical applications of imaging AOTF. Additionally, the AOTF based hyperspectral microscopic imaging system is established. The stability and the image resolution of the designed narrow band AOTF are satisfying. Finally, the study of the biologic samples indicates the feasibility of our system on biomedicine. (paper)

  4. Plasma optical modulators for intense lasers

    CERN Document Server

    Yu, Lu-Le; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D A; Mori, W B; Zhang, Jie

    2016-01-01

    Optical modulators can be made nowadays with high modulation speed, broad bandwidth, while being compact, owing to the recent advance in material science and microfabrication technology. However, these optical modulators usually work for low intensity light beams. Here, we present an ultrafast, plasma-based optical modulator, which can directly modulate high power lasers with intensity up to 10^16 W/cm^2 level to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser beams in a sub-mm-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser beam is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are presented. Such optical modulators may enable new applications in the high field physics.

  5. Binary Modulation Formats in Optical Access Networks

    Directory of Open Access Journals (Sweden)

    Vladimir Tejkal

    2010-01-01

    Full Text Available In this paper the binary modulation formats and their application in passive optical networks have been discussed. Passive optical networks are characterized by dividing the optical signal between several end users by using passive splitters, which added a significant attenuation to the network. The performance of the selected modulation formats, depending on the transmitter power in order to verify that there is no signal distortion, has been examined in our simulations. A minimal error rate of the system for each modulation format has been also examined. Finding a suitable modulation, which would allow extension of the distance and splitting ration in current passive optical networks, has been the main aim.

  6. Noise and detection in ''optical'' modulation spectroscopy

    International Nuclear Information System (INIS)

    The measuring techniques suitable for ''optical'' modulation spectroscopy are analyzed and source of noise identified. The choice of optical detector is for photoelectrical devices. It is shown that the shot noise of phototubes is the most important noise source

  7. Phase-Modulated Optical Communication Systems

    CERN Document Server

    Ho, Keang-Po

    2005-01-01

    Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: The transmitter and receiver for phase-modulated coherent lightwave systems Method for performance analysis o...

  8. Nanosecond liquid crystalline optical modulator

    Energy Technology Data Exchange (ETDEWEB)

    Borshch, Volodymyr; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2016-07-26

    An optical modulator includes a liquid crystal cell containing liquid crystal material having liquid crystal molecules oriented along a quiescent director direction in the unbiased state, and a voltage source configured to apply an electric field to the liquid crystal material wherein the direction of the applied electric field does not cause the quiescent director direction to change. An optical source is arranged to transmit light through or reflect light off the liquid crystal cell with the light passing through the liquid crystal material at an angle effective to undergo phase retardation in response to the voltage source applying the electric field. The liquid crystal material may have negative dielectric anisotropy, and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is transverse to the quiescent director direction. Alternatively, the liquid crystal material may have positive dielectric anisotropy and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is parallel with the quiescent director direction.

  9. Efficient diode-pumped acousto-optic Q-switched Er:Yb:GdAl(3)(BO(3))(4) pulse laser at 1522  nm.

    Science.gov (United States)

    Chen, Y J; Lin, Y F; Huang, J H; Gong, X H; Luo, Z D; Huang, Y D

    2015-11-01

    End-pumped by a continuous-wave 976 nm diode laser, efficient 1522 nm laser operation was demonstrated in an Er:Yb:GdAl(3)(BO(3))(4) crystal when a sapphire crystal was used as a heat diffuser. A continuous-wave 1522 nm laser with a maximum output power of 750 mW and slope efficiency of 36% was realized at an absorbed pump power of 4.1 W. The pulse performances of an acousto-optic Q-switched laser with various repetition frequencies were investigated in detail. In a repetition frequency range of 1-10 kHz, 1522 nm pulse lasers with a slope efficiency of about 10%, peak output power at the kilowatt level, and width of about 50 ns were first obtained in an Er:Yb:GdAl(3)(BO(3))(4) crystal pumped by a continuous-wave diode laser. The results indicate that the crystal is a promising gain medium for an actively Q-switched 1.5 μm laser. PMID:26512485

  10. A graphene-based broadband optical modulator

    Science.gov (United States)

    Liu, Ming; Yin, Xiaobo; Ulin-Avila, Erick; Geng, Baisong; Zentgraf, Thomas; Ju, Long; Wang, Feng; Zhang, Xiang

    2011-06-01

    Integrated optical modulators with high modulation speed, small footprint and large optical bandwidth are poised to be the enabling devices for on-chip optical interconnects. Semiconductor modulators have therefore been heavily researched over the past few years. However, the device footprint of silicon-based modulators is of the order of millimetres, owing to its weak electro-optical properties. Germanium and compound semiconductors, on the other hand, face the major challenge of integration with existing silicon electronics and photonics platforms. Integrating silicon modulators with high-quality-factor optical resonators increases the modulation strength, but these devices suffer from intrinsic narrow bandwidth and require sophisticated optical design; they also have stringent fabrication requirements and limited temperature tolerances. Finding a complementary metal-oxide-semiconductor (CMOS)-compatible material with adequate modulation speed and strength has therefore become a task of not only scientific interest, but also industrial importance. Here we experimentally demonstrate a broadband, high-speed, waveguide-integrated electroabsorption modulator based on monolayer graphene. By electrically tuning the Fermi level of the graphene sheet, we demonstrate modulation of the guided light at frequencies over 1GHz, together with a broad operation spectrum that ranges from 1.35 to 1.6µm under ambient conditions. The high modulation efficiency of graphene results in an active device area of merely 25µm2, which is among the smallest to date. This graphene-based optical modulation mechanism, with combined advantages of compact footprint, low operation voltage and ultrafast modulation speed across a broad range of wavelengths, can enable novel architectures for on-chip optical communications.

  11. Plasma optical modulators for intense lasers

    Science.gov (United States)

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-06-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm-2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations.

  12. Plasma optical modulators for intense lasers

    Science.gov (United States)

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-01-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm−2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations. PMID:27283369

  13. Highly Sensitive Electro-Optic Modulators

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, Peter S [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  14. Optically Modulated Multiband Terahertz Perfect Absorber

    DEFF Research Database (Denmark)

    Seren, Huseyin R.; Keiser, George R.; Cao, Lingyue;

    2014-01-01

    response of resonant metamaterials continues to be a challengingendeavor. Resonant perfect absorbers have flourished as one of the mostpromising metamaterial devices with applications ranging from power har-vesting to terahertz imaging. Here, an optically modulated resonant perfectabsorber is presented...

  15. The optical module of Baikal-GVD

    Directory of Open Access Journals (Sweden)

    Avrorin A.D.

    2016-01-01

    Full Text Available The Baikal-GVD neutrino telescope in Lake Baikal is intended for studying astrophysical neutrino fluxes by recording the Cherenkov radiation of the secondary muons and showers generated in neutrino interactions. The first stage of Baikal-GVD will be equipped with about 2300 optical modules. We describe the design of the optical module, the front-end electronics and the laboratory characterization and calibration before deployment.

  16. Polybinary modulation for bandwidth limited optical links

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Jurado-Navas, Antonio

    2015-01-01

    Optical links using traditional modulation formats are reaching a plateau in terms of capacity, mainly due to bandwidth limitations in the devices employed at the transmitter and receivers. Advanced modulation formats, which boost the spectral efficiency, provide a smooth migration path towards e...

  17. Efficient and high-power green beam generation by frequency doubling of acousto-optic Q-switched diode-side pumped Nd:YAG rod laser in a coupled cavity

    Indian Academy of Sciences (India)

    S K Sharma; A J Singh; P K Mukhopadhyay; S M Oak

    2010-11-01

    A 52-W green laser at 532 nm by extra-cavity second-harmonic generation in a coupled-cavity configuration is demonstrated. The fundamental laser is a diode-side-pumped acousto-optic (AO) Q-switched Nd:YAG rod laser producing 84 W of average power at 1064 nm at 8 kHz repetition rate. Type-II phase-matched polished KTP crystal is used as the nonlinear crystal for second-harmonic generation. The individual green pulse width is 50 ns and the fundamental to second harmonic conversion efficiency is 61.8%.

  18. Frequency-modulated continuous-wave lidar using I/Q modulator for simplified heterodyne detection.

    Science.gov (United States)

    Gao, S; Hui, R

    2012-06-01

    A frequency-modulated continuous-wave (FMCW) lidar is demonstrated with heterodyne detection. The lidar transmitter utilizes an electro-optic I/Q modulator for the first time to generate carrier-suppressed and frequency-shifted FM modulation. This eliminates the need for an acousto-optic frequency shifter commonly used in heterodyne lidar transmitters. It also allows the use of a much wider modulation bandwidth to improve the range resolution. The capability of complex optical field modulation of the I/Q modulator provides an additional degree of freedom compared with an intensity modulator, which will benefit future lidar applications. PMID:22660108

  19. 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

  20. Electric modulation of optical absorption in nanowires

    Science.gov (United States)

    Sakr, M. R.

    2016-11-01

    We have calculated the effect of an external electric field on the intersubband optical absorption of a nanowire subjected to a perpendicular magnetic field and Rashba effect. The absorption peaks due to optical transitions that are forbidden in the absence of the intersubband coupling experience strong amplitude modulation. This effect is quadratic in electric fields applied along the direction of quantum confinement or perpendicularly to tune the Rashba parameter. The electric field also induces frequency modulation in the associated spectrum. On the other hand, transitions that are normally allowed show, to a large extent, a parallel band effect, and accordingly they are responsible for strong optical absorption.

  1. Optical Response of a Liquid Crystal modulator

    International Nuclear Information System (INIS)

    The progress in liquid crystal device technology has led to the development of different electro-optical displays from simple digital watchs to high information content computer screens. In these electro-optical systems modulation of light by means of a liquid crystal device is very important subject both from the point of fundamental physics and for possible technological applications. In this study we describe a liquid crystal modulator which consists of a thin film of liquid crystal contained between parallel conductive glass plates. The surfaces of the plates are treated so that the liquid crystal molecules are parallel to the surfaces but twists about an axis normal to the surfaces by an angle of 90 degree from one substrate to the other. In a liquid crystal modulator the dielectric and optical anisotropies are used to modulate a laser beam passing through the film. If an electric field is applied across the film the molecules realign parallel to the electric field to form the homeotropic structure which has no optical modulation effect. Thus, the electric field-dependent transmission of the liquid crystal modulator is characterized. We also analyze the response behavior of the liquid crystal modulator

  2. Method and apparatus of highly linear optical modulation

    Energy Technology Data Exchange (ETDEWEB)

    DeRose, Christopher; Watts, Michael R.

    2016-05-03

    In a new optical intensity modulator, a nonlinear change in refractive index is used to balance the nonlinearities in the optical transfer function in a way that leads to highly linear optical intensity modulation.

  3. Monte Carlo Simulation of Scattered Light with Shear Waves Generated by Acoustic Radiation Force for Acousto-Optic Imaging

    International Nuclear Information System (INIS)

    A Monte Carlo method of multiple scattered coherent light with the information of shear wave propagation in scattering media is presented. The established Monte-Carlo algorithm is mainly relative to optical phase variations due to the acoustic-radiation-force shear-wave-induced displacements of light scatterers. Both the distributions and temporal behaviors of optical phase increments in probe locations are obtained. Consequently, shear wave speed is evaluated quantitatively. It is noted that the phase increments exactly track the propagations of shear waves induced by focus-ultrasound radiation force. In addition, attenuations of shear waves are demonstrated in simulation results. By using linear regression processing, the shear wave speed, which is set to 2.1 m/s in simulation, is estimated to be 2.18 m/s and 2.35 m/s at time sampling intervals of 0.2 ms and 0.5 ms, respectively

  4. Advanced instrumentation for acousto-ultrasonic based structural health monitoring

    Science.gov (United States)

    Smithard, Joel; Galea, Steve; van der Velden, Stephen; Powlesland, Ian; Jung, George; Rajic, Nik

    2016-04-01

    Structural health monitoring (SHM) systems using structurally-integrated sensors potentially allow the ability to inspect for damage in aircraft structures on-demand and could provide a basis for the development of condition-based maintenance approaches for airframes. These systems potentially offer both substantial cost savings and performance improvements over conventional nondestructive inspection (NDI). Acousto-ultrasonics (AU), using structurallyintegrated piezoelectric transducers, offers a promising basis for broad-field damage detection in aircraft structures. For these systems to be successfully applied in the field the hardware for AU excitation and interrogation needs to be easy to use, compact, portable, light and, electrically and mechanically robust. Highly flexible and inexpensive instrumentation for basic background laboratory investigations is also required to allow researchers to tackle the numerous scientific and engineering issues associated with AU based SHM. The Australian Defence Science and Technology Group (DST Group) has developed the Acousto Ultrasonic Structural health monitoring Array Module (AUSAM+), a compact device for AU excitation and interrogation. The module, which has the footprint of a typical current generation smart phone, provides autonomous control of four send and receive piezoelectric elements, which can operate in pitch-catch or pulse-echo modes and can undertake electro-mechanical impedance measurements for transducer and structural diagnostics. Modules are designed to operate synchronously with other units, via an optical link, to accommodate larger transducer arrays. The module also caters for fibre optic sensing of acoustic waves with four intensity-based optical inputs. Temperature and electrical resistance strain gauge inputs as well as external triggering functionality are also provided. The development of a Matlab hardware object allows users to easily access the full hardware functionality of the device and

  5. Ultrafast all-optical graphene modulator.

    Science.gov (United States)

    Li, Wei; Chen, Bigeng; Meng, Chao; Fang, Wei; Xiao, Yao; Li, Xiyuan; Hu, Zhifang; Xu, Yingxin; Tong, Limin; Wang, Hongqing; Liu, Weitao; Bao, Jiming; Shen, Y Ron

    2014-02-12

    Graphene is an optical material of unusual characteristics because of its linearly dispersive conduction and valence bands and the strong interband transitions. It allows broadband light-matter interactions with ultrafast responses and can be readily pasted to surfaces of functional structures for photonic and optoelectronic applications. Recently, graphene-based optical modulators have been demonstrated with electrical tuning of the Fermi level of graphene. Their operation bandwidth, however, was limited to about 1 GHz by the response of the driving electrical circuit. Clearly, this can be improved by an all-optical approach. Here, we show that a graphene-clad microfiber all-optical modulator can achieve a modulation depth of 38% and a response time of ∼ 2.2 ps, limited only by the intrinsic carrier relaxation time of graphene. This modulator is compatible with current high-speed fiber-optic communication networks and may open the door to meet future demand of ultrafast optical signal processing. PMID:24397481

  6. Graphene Based Optical Phase Modulation

    CERN Document Server

    Midrio, Michele; Romagnoli, Marco; Kimerling, Lionel C; Michel, Jurgen

    2013-01-01

    In this paper we report phase modulation obtained by inducing a capacitive charge on graphene layers embedded in the core of a waveguide. There is a biasing regime in which graphene absorption is negligible but large index variations can be achieved with a voltage-length product as small as $V_\\pi\\,L_\\pi \\simeq 0.04 $\\,V\\,cm . Examples of phase induced changes are computed for straight waveguides and for microring resonators showing the possibility to implement several optoelectronic functionalities as modulators, tunable filters, and switches.

  7. Acousto-optic Q-switched laser performances of Er3+∶yb3+∶LuAl3(BO3)4 crystal at 1.5-1.6 μm

    Institute of Scientific and Technical Information of China (English)

    Yujin Chen; Yanfu Lin; Haiyong Zhu; Ge Zhang; Yidong Huang

    2012-01-01

    Diode-pumped acousto-optic Q-switched pulse laser at 1.5-1.6μm is obtained in an Er3+:Yb3+:LuAl3 (BO3)4 crystal. Single-pulse laser operation with slope efficiency of 14% and threshold of approximately 100 mW is realized at an average absorbed pump power of 314 mW and repetition frequency of 20 kHz. Output pulse energy is 67 μJ. The effects of pulse repetition frequency, absorbed pump power, and duty cycle on the wavelength and pulse profile of the Q-switched Er3+:Yb3+:LuAl3(BO3)4 laser are also investigated.%Diode-pumped acousto-optic Q-switched pulse laser at 1.5-1.6 μm is obtained in an Er3+∶Yb3+∶LuAl3 (BO3)4 crystal.Single-pulse laser operation with slope efficiency of 14% and threshold of approximately 100 mW is realized at an average absorbed pump power of 314 mW and repetition frequency of 20 kHz.Output pulse energy is 67 μJ.The effects of pulse repetition frequency,absorbed pump power,and duty cycle on the wavelength and pulse profile of the Q-switched Er3+∶yb3+∶LuAl3(BO3)4 laser are also investigated.

  8. An acousto-optic Q-switched fiber laser using China-made double-cladding fiber

    Institute of Scientific and Technical Information of China (English)

    Hongming Zhao; Qihong Lou; Jun Zhou; Fangpei Zhang; Jingxing Dong; Yunrong Wei; Libo Li; Zhijiang Wang

    2007-01-01

    @@ A simple laser-diode pumped acoustic-optic Q-switched fiber laser is reported by using China-made largemode-area ytterbium-doped fiber. Q-switched pulses with a beam quality factor of M2 ≈ 2 and several hundred nanoseconds pulse duration are achieved at the repetition rate of 1 - 50 kHz. When the repetition rate is 1 kHz, the pulse energy is 0.93 mJ with the pulse duration of 132 ns. Meanwhile, the profile of laser pulses shows some mode-locking phenomena, the mechanism of the phenomena is discussed.

  9. Acousto-optic effect in a nematic liquid-crystal layer under the binary effect of sound and viscous waves

    Energy Technology Data Exchange (ETDEWEB)

    Kozhevnikov, E. N., E-mail: kozhev@ssu.samara.ru [Samara State University (Russian Federation)

    2010-03-15

    The optical effect in a liquid crystal cell containing a homeotropic layer of nematic liquid crystal (NLC) is analyzed. An NLC layer, located between crossed polaroids and opaque in the absence of external effect, is cleared after irradiation by an ultrasonic beam with a sharp spatial boundary. This enlightenment is suggested to be caused by the reorientation of crystal molecules in the acoustic flows that arise under the binary effect of the layer compression in the irradiated region and the viscous waves propagating from the layer boundaries. The flows were calculated taking into account the stress caused by the velocity convection and crystal structure relaxation. An expression is derived for the cell transparency, and the relative role of the convection and relaxation processes in the effect is determined.

  10. Acousto-optic effect in a nematic liquid-crystal layer under the binary effect of sound and viscous waves

    International Nuclear Information System (INIS)

    The optical effect in a liquid crystal cell containing a homeotropic layer of nematic liquid crystal (NLC) is analyzed. An NLC layer, located between crossed polaroids and opaque in the absence of external effect, is cleared after irradiation by an ultrasonic beam with a sharp spatial boundary. This enlightenment is suggested to be caused by the reorientation of crystal molecules in the acoustic flows that arise under the binary effect of the layer compression in the irradiated region and the viscous waves propagating from the layer boundaries. The flows were calculated taking into account the stress caused by the velocity convection and crystal structure relaxation. An expression is derived for the cell transparency, and the relative role of the convection and relaxation processes in the effect is determined.

  11. Use of acousto-optic grating as a sensor for determining the adulteration in liquids being used in daily life

    Science.gov (United States)

    Soni, Kirti; Kasana, R. S.

    2008-01-01

    An optical sensor has been developed for finding the proportional composition of two liquids in a mixture. The variation of the refractive index of a liquid produces light diffraction phenomenon. A liquid mixture is filled in a rectangular glass cell, which is placed orthogonically to the incident collimated beams of light. This cell consists of a piezoelectric crystal vibrator for generating ultrasonic waves. The collimated light while passing through this cell gets diffracted. The diffracted dots are collected by a converging lens and displayed in the back focal plane of the lens. The location of the diffracted dots decide the composition of mixture constituents namely fuel oils, edible oils, wine, water, etc. Thus, the adulteration of various liquids can be determined by having the knowledge of the position of diffraction dots.

  12. Brainwave Acousto-Optic Adjuster Based on Binaural Auditory Beat%基于双声拍的脑电波声光调节装置

    Institute of Scientific and Technical Information of China (English)

    张晓磊; 姚俊强; 沈斌; 应家顺; 彭雪峰

    2013-01-01

    A brainwave acousto-optic adjuster based on binaural auditory beat was designed by the use of the ATmega8.When two tones of slightly different frequency are presented separately to the left and right ears,the listener perceives a single tone that varies in amplitude at a frequency equal to the frequency difference between the two tones,which was known as "Binaural Auditory Beats (BAT)".The BAT within the brainwave frequency range can affect brain activity and states of consciousness,so we can adjust the brainwave by the BAT.Make use of this law,we product two auditory signals with different frequency by ATmega8,after low pass filter,presented separately to the left and right ear,formed BAT,then set two LEDs flash with the same frequency as the BAT before the left and right eyes.The combined action of light and BAT with the same frequency could adjust the brainwave arbitrarily.%利用ATmega8单片机制作了一种基于双声拍的脑电波光电调节装置.两列频率差别较小的声波分别输入人的左右耳中,会产生一种振幅周期性变化的新的声波,新声波的频率为原来两列声波的频率差,这种现象称为“双声拍”.双声拍的频率位于人脑电波范围时会影响大脑的活跃程度和意识状态,通过调节双声拍的频率即可调节脑电波.基于这一原理,本文利用ATmega8单片机产生两列声波,低通滤波后将不同频率的声波通过左右耳输入大脑,形成“双声拍”;再将双眼前放置两个闪烁频率与双声拍频相同的LED,在声光的共同作用下,可以达到任意调节脑电波频率的目的.

  13. Reconstructions in ultrasound modulated optical tomography

    KAUST Repository

    Allmaras, Moritz

    2011-01-01

    We introduce a mathematical model for ultrasound modulated optical tomography and present a simple reconstruction scheme for recovering the spatially varying optical absorption coefficient from scanning measurements with narrowly focused ultrasound signals. Computational results for this model show that the reconstruction of sharp features of the absorption coefficient is possible. A formal linearization of the model leads to an equation with a Fredholm operator, which explains the stability observed in our numerical experiments. © de Gruyter 2011.

  14. Absolute frequency synthesis of pulsed coherent light waves through phase-modulation active optical feedback.

    Science.gov (United States)

    Shimizu, K; Horiguchi, T; Koyamada, Y

    1996-11-15

    A novel method for the broadband absolute frequency synthesis of pulsed coherent lightwaves is demonstrated. It is based on pulse recirculation around an active optical feedback ring containing a delay-line fiber, an external phase modulator, an acousto-optic frequency shifter (AOFS), and a high-finesse Fabry-Perot étalon. The modulation frequency F(M) and the frequency shift F(AO) that are due to AOFS are designed so that their sum or difference equals the free-spectral range of the étalon and F(AO) is set at larger than the half-width at full maximum of its resonant peaks. If one of the peak frequencies is tuned to the frequency of the initial pulse, the frequency of the recirculating pulse jumps to the next peak for each round trip. In the experiment the absolute frequency is synthesized over a frequency span of 700 GHz around the initial stabilized frequency of the master laser.

  15. COANP-fullerenes system for optical modulation

    Science.gov (United States)

    Likhomanova, S. V.; Kamanina, N. V.

    2016-08-01

    The advanced investigations of ϕ-conjugated organic molecule COANP sensitized with fullerenes have been revealed to consider this system as an affective medium for optical limiting and phase modulation. The special accent has been given to influence of the nanostructured relief at the interface on the spectral and photoconductive features.

  16. An acousto-optic beamformer

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2012-01-01

    There is a great variety of beamforming techniques that can be used for localization of sound sources. The differences among them usually lie in the array layout or in the specific signal processing algorithm used to compute the beamforming output. Any beamforming system consists of a finite numb...

  17. Virtual k -Space Modulation Optical Microscopy

    Science.gov (United States)

    Kuang, Cuifang; Ma, Ye; Zhou, Renjie; Zheng, Guoan; Fang, Yue; Xu, Yingke; Liu, Xu; So, Peter T. C.

    2016-07-01

    We report a novel superresolution microscopy approach for imaging fluorescence samples. The reported approach, termed virtual k -space modulation optical microscopy (VIKMOM), is able to improve the lateral resolution by a factor of 2, reduce the background level, improve the optical sectioning effect and correct for unknown optical aberrations. In the acquisition process of VIKMOM, we used a scanning confocal microscope setup with a 2D detector array to capture sample information at each scanned x -y position. In the recovery process of VIKMOM, we first modulated the captured data by virtual k -space coding and then employed a ptychography-inspired procedure to recover the sample information and correct for unknown optical aberrations. We demonstrated the performance of the reported approach by imaging fluorescent beads, fixed bovine pulmonary artery endothelial (BPAE) cells, and living human astrocytes (HA). As the VIKMOM approach is fully compatible with conventional confocal microscope setups, it may provide a turn-key solution for imaging biological samples with ˜100 nm lateral resolution, in two or three dimensions, with improved optical sectioning capabilities and aberration correcting.

  18. Modeling of a Resonant Tunneling Diode Optical Modulator

    OpenAIRE

    Calado, J. J. N.; Figueiredo, J.M.L.; Ironside, C. N.

    2005-01-01

    The integration of a double barrier resonant tunneling diode within a unipolar optical waveguide provides electrical gain over a wide bandwidth. Due to the non-linearities introduced by the double barrier resonant tunneling diode an unipolar InGaAlAs/InP optical waveguide can be employed both as optical modulator and optical detector. The modeling results of a device operating as optical modulator agree with preliminary experimental data, foreseeing for an optimized device modulation depths u...

  19. Highly reproducible Bragg grating acousto-ultrasonic contact transducers

    Science.gov (United States)

    Saxena, Indu Fiesler; Guzman, Narciso; Lieberman, Robert A.

    2014-09-01

    Fiber optic acousto-ultrasonic transducers offer numerous applications as embedded sensors for impact and damage detection in industrial and aerospace applications as well as non-destructive evaluation. Superficial contact transducers with a sheet of fiber optic Bragg gratings has been demonstrated for guided wave ultrasound based measurements. It is reported here that this method of measurement provides highly reproducible guided ultrasound data of the test composite component, despite the optical fiber transducers not being permanently embedded in it.

  20. Optical antennas with sinusoidal modulation in width.

    Science.gov (United States)

    Dikken, Dirk Jan; Segerink, Frans B; Korterik, Jeroen P; Pfaff, Stefan S; Prangsma, Jord C; Herek, Jennifer L

    2016-08-01

    Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in width. We experimentally show that by changing the phase of the width-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm. Using simulations we show how this simple design can create resonance shifts greater than 600 nm. The versatility of this design is further shown by creating asymmetric structures with two different modulation amplitudes, which we experimentally and numerically show to give rise to two resonances. Our results on both the symmetric and asymmetric antennas show the capability to control the localization of the fields outside the antenna, while still maintaining the freedom to change the antenna resonance wavelength. The antenna design we tested combines a large spectral tunability with a small footprint: all the antenna dimensions are factor 7 to 13 smaller than the wavelength, and hold potential as a design element in meta-surfaces for beam shaping.

  1. Optical frequency-modulated continuous-wave interferometers.

    Science.gov (United States)

    Zheng, Jesse

    2006-04-20

    I discuss optical frequency-modulated continuous-wave (FMCW) interferometers, including their principles, characteristics, specific requirements, procedure for their construction, optical configurations, primary applications, optical sources, resolution, measurement range, and stability. PMID:16633422

  2. Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

    Science.gov (United States)

    Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

    2008-02-01

    Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

  3. Multiple Isotope Magneto Optical Trap from a single diode laser

    CERN Document Server

    Valenzuela, V M; Gutierrez, M; Gomez, E; 10.1364/JOSAB.30.001205

    2013-01-01

    We present a Dual Isotope Magneto Optical Trap produced using a single diode laser. We generate all the optical frequencies needed for trapping both species using a fiber intensity modulator. All the optical frequencies are amplified simultaneously using a tapered amplifier. The independent control of each frequency is on the RF side rather than on the optical side. This introduces an enormous simplification for laser cooling applications that often require an acousto-optic modulator for each laser beam. Frequency changing capabilities are limited by the modulator bandwidth (10 GHz). Traps for more isotopes can be simply added by including additional RF frequencies to the modulator.

  4. Planar Silicon Optical Waveguide Light Modulators

    DEFF Research Database (Denmark)

    Leistiko, Otto; Bak, H.

    1994-01-01

    The results of an experimental investigation of a new type of optical waveguide based on planar technology in which the liglht guiding and modulation are achieved by exploiting free carrier effects in silicon are presented. Light is guided between the n+ substrate and two p+ regions, which also...... serve as carrier injectors for controling absorption. Light confinement of single mode devices is good, giving spot sizes of 9 ¿m FWHM. Insertion loss measurements indicate that the absorption losses for these waveguides are extremely low, less 1 dB/cm. Estimates of the switching speed indicate...

  5. New modulator for the optical signal in a fiber

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian-hao; JIA Feng; WANG Shun-li; MAN Jiang wei; NIU Kai; WANG Xu-cheng; YANG Jia

    2006-01-01

    A new modulator for the optical signal in a fiber based on multi-beam interference is designed. In the experiment,the distance of a couple of abutted fibers was modulated through a piezoelectric ceramic pipe driven by 50 Hz AC voltage, so that the amplitude of the transmitted optical signal was modulated. The modulation ratio is about 10% ,S/N ratio is about 60 dB and the bandwidth is about 200 KHz.

  6. Performance Research of Modulation for Optical Wireless Communication System

    OpenAIRE

    Yan Gao; Min Wu; Weifeng Du

    2011-01-01

    There are many modulation methods suitable for optical wireless communication. OOK, PPM are adopted widely in optical wireless communication for its high average-power-efficiency. DPPM, DPIM and DH-PIM are three new modulation methods for optical wireless communication, which may be the substitutes of PPM because of their better performance in power efficiency and bandwidth efficiency. In this paper, in combination of the characteristic of the atmospheric optical wireless channel, the bandwid...

  7. Modeling of a Resonant Tunneling Diode Optical Modulator

    CERN Document Server

    Calado, J J N; Ironside, C N

    2005-01-01

    The integration of a double barrier resonant tunneling diode within a unipolar optical waveguide provides electrical gain over a wide bandwidth. Due to the non-linearities introduced by the double barrier resonant tunneling diode an unipolar InGaAlAs/InP optical waveguide can be employed both as optical modulator and optical detector. The modeling results of a device operating as optical modulator agree with preliminary experimental data, foreseeing for an optimized device modulation depths up to 23 dB with chirp parameter between -1 and 0 in the wavelength range analyzed (1520 nm - 1600 nm).

  8. The Research of the Baker Code Correlation Peak Extraction Method of Acousto-optic Correlator%声光相关器巴克码相关峰提取方法的研究

    Institute of Scientific and Technical Information of China (English)

    王素铭; 周鹰; 杨立峰; 王亚非; 高椿明; 王占平

    2012-01-01

    Acousto-optic signal processing is a sort of technology of spectrum analysis and correlation, taking a-cousto-optic device as the core, with the features of large instantaneous bandwidth, dynamic range, processing gain and high speed parallel capacity. According to the principle of incoherent time-integrating correlator, the methods of polynomial fitting and wavelet transform are used to resolve the problem of correlation peak extraction of baker code. At last, experimental results and comparison of two methods are also given.%声光信号处理技术是以声光器件为核心的频谱分析技术和相关处理技术,具有大瞬时带宽、大动态范围、高处理增益和高速并行能力.根据非相干时间积分声光相关器原理,针对巴克码相关峰提取问题,提出了多项式拟合和小波变换两种峰值提取方法,对两种方法进行了比较,并对实验结果进行了分析.

  9. Applications of ``PV Optics`` for solar cell and module design

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L.; Madjdpour, J.; Chen, W. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper describes some applications of a new optics software package, PV Optics, developed for the optical design of solar cells and modules. PV Optics is suitable for the analysis and design of both thick and thin solar cells. It also includes a feature for calculation of metallic losses related to contacts and back reflectors.

  10. Microwave Magneto-Optic Bragg Modulators with Rectangular MSFVW Pulses

    Institute of Scientific and Technical Information of China (English)

    Cheng-You Luo; Bao-Jian Wu; Kun Qiu

    2009-01-01

    Microwave magneto-optic (MO) modu- lators can directly transform radio frequency (RF) signals into optical data through the Bragg diffraction of guided optical waves (GOWs) induced by microwave magneto-static waves (MSWs). According to the MO coupled-mode theory, the modulation of continuous GOWs by a rectangular magneto-static-forward- volume-wave (MSFVW) pulse in MO film waveguide is studied in the small signal case and the modulated optical pulse at the output is analyzed by means of an analytical form, which is dependent on the instantaneous diffraction intensity determined by the overlap of rectangular MSFVW pulse and light beam aperture. On the basis of it, the characteristics of MSFVW-based MO modulators can be explained well for the case of rectangular pulse modulation. It is also shown that the line codes of optical data generated by MO Bragg modulators can be controlled by adjusting the duty factor of modulating pulse signals.

  11. Advanced Modulation Techniques for High-Performance Computing Optical Interconnects

    DEFF Research Database (Denmark)

    Karinou, Fotini; Borkowski, Robert; Zibar, Darko;

    2013-01-01

    We experimentally assess the performance of a 64 × 64 optical switch fabric used for ns-speed optical cell switching in supercomputer optical interconnects. More specifically, we study four alternative modulation formats and detection schemes, namely, 10-Gb/s nonreturn-to-zero differential phase...... of the optical shared memory supercomputer interconnect system switch fabric. In particular, we investigate the resilience of the aforementioned advanced modulation formats to the nonlinearities of semiconductor optical amplifiers, used as ON/OFF gates in the supercomputer optical switch fabric under study...

  12. All-optical demultiplexing using an electroabsorption modulator

    OpenAIRE

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    2000-01-01

    In the 1990s, the electroabsorption modulator (EAM) has found a wide range of applications. Functionalities such as pulse generation and demultiplexing by electrical modulation have been demonstrated using an EAM. Recently, all-optical wavelength conversion, demultiplexing, and signal regeneration, have also been experimentally demonstrated. In this paper, we investigate all-optical demultiplexing from 80 to 10 Gbit/s.

  13. Modulational instability of short pulses in long optical fibers

    DEFF Research Database (Denmark)

    Shukla, P. K.; Juul Rasmussen, Jens

    1986-01-01

    The effect of time-derivative nonlinearity is incorporated into the study of the modulational instability of heat pulses propagating through long optical fibers. Conditions for soliton formation are discussed......The effect of time-derivative nonlinearity is incorporated into the study of the modulational instability of heat pulses propagating through long optical fibers. Conditions for soliton formation are discussed...

  14. Analysis of optical frequency-modulated continuous-wave interference.

    Science.gov (United States)

    Zheng, Jesse

    2004-07-20

    I systematically analyze the theory of optical frequency-modulated continuous-wave (FMCW) interference. There are three different versions of optical FMCW interference, discussed in detail: sawtooth-wave optical FMCW interference, triangular-wave optical FMCW interference, and sinusoidal-wave optical FMCW interference. The essential concepts and technical terms are clearly defined, the necessary simplifications are introduced according to the characteristics of optical waves, and the formulas used to calculate the signal intensities under two different situations (static and dynamic) are properly derived. Advantages and limitations of each version of optical FMCW interference are also discussed. PMID:15291063

  15. Ultrasound-modulated optical tomography for thick tissue imaging

    Science.gov (United States)

    Wang, Lihong V.; Zhao, Xuemei; Jacques, Steven L.

    1995-12-01

    Continuous-wave ultrasonic modulation of scattered laser light has been used to image objects in tissue-simulating turbid media for the first time. We hypothesize that the ultrasound wave focused into the turbid media modulates the laser light passing through the ultrasonic focal spot. The modulated laser light collected by a photomultiplier tube reflects the local mechanical and optical properties in the focal zone. Buried objects in 5-cm thick tissue phantoms are located with millimeter resolution by scanning and detecting alterations of the ultrasound-modulated optical signal. Ultrasound-modulated optical tomography separates the conflict between signal and resolution in purely optical imaging of tissue and does not rely on ballistic or quasi-ballistic photons but on the abundant diffuse photons. The imaging resolution is determined by the focused ultrasonic wave. This technique has the potential to provide a noninvasive, nonionizing, inexpensive diagnostic tool for diseases such as breast cancer.

  16. Multifunctional graphene optical modulator and photodetector integrated on silicon waveguides

    CERN Document Server

    Youngblood, Nathan; Ma, Rui; Koester, Steven J; Li, Mo

    2014-01-01

    For optical communication, information is converted between optical and electrical signal domains at a high rate. The devices to achieve such a conversion are various types of electro-optical modulators and photodetectors. These two types of optoelectronic devices, equally important, require different materials and consequently it has been challenging to realize both using a single material combination, especially in a way that can be integrated on the ubiquitous silicon platform. Graphene, with its gapless band structure, stands out as a unique optoelectronic material that allows both photodetection and optical modulation. Here, we demonstrate a single graphene-based device that simultaneously provides both efficient optical modulation and photodetection. The graphene device is integrated on a silicon waveguide and is tunable with a gate made from another layer of graphene to achieve near-infrared photodetection responsivity of 57 mA/W and modulation depth of 64%. This novel multifunctional device may lead t...

  17. A process to control light in a micro resonator through a coupling modulation by surface acoustic waves

    Science.gov (United States)

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan

    2016-08-01

    A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW.

  18. Monolithically integrated quantum dot optical modulator with Semiconductor optical amplifier for short-range optical communications

    Science.gov (United States)

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

    2015-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed. Broadband QD optical gain material was used to achieve Gbps-order high-speed optical data transmission, and an optical gain change as high as approximately 6-7 dB was obtained with a low OGM voltage of 2.0 V. Loss of optical power due to insertion of the device was also effectively compensated for by the SOA section. Furthermore, it was confirmed that the QD-OGM/SOA device helped achieve 6.0-Gbps error-free optical data transmission over a 2.0-km-long photonic crystal fiber. We also successfully demonstrated generation of Gbps-order, high-speed, and error-free optical signals in the >5.5-THz broadband optical frequency bandwidth larger than the C-band. These results suggest that the developed monolithically integrated QD-OGM/SOA device will be an advantageous and compact means of increasing the usable optical frequency channels for short-reach communications.

  19. Optical Bistability And Hysteresis In A Solid State Ring Laser

    Science.gov (United States)

    Kornienko, L. S.; Kravtsov, N. S.; Shelaev, A. N.

    1985-01-01

    The phenomena of optical bistability, hysteresis and memory under the interaction of oppositely directed (OD) light waves in a CW YAG:Nd3+ solid state ring laser (SRL) have been experimentally discovered. The possibilities of spontaneous or forced (with modulated SRL parameters) commutation of the radiation direction without transients at the relaxation frequency (typical for solid state lasers) have been established both in the single-mode and in the mode-locking regimes with various feedback circuits. The mode-locking band was found to be substantially broadened by more than an order of magnitude when OD light waves primarily diffracted on a standing ultrasonic wave were returned into the acousto-optical modulator. With such acousto-optical feedback the mode-locking regime has been obtained using a modulator on a running ultrasonic wave.

  20. Ultrasound-modulated optical tomography for dense turbid media

    Science.gov (United States)

    Wang, Lihong V.; Zhao, Xuemei; Jacques, Steven L.

    1996-04-01

    Continuous-wave ultrasonic modulation of scattered laser light has been used to image objects in tissue-simulating turbid media for the first time. We hypothesized that the ultrasound wave focused into the turbid media modulates the laser light passing through the ultrasonic focal zone. The modulated laser light collected by a photomultiplier tube reflects the local mechanical and optical properties in the focal zone. Buried objects in 5-cm thick tissue phantoms (absorption coefficient (mu) $a) equals 0.1 cm-1, reduced scattering coefficient (mu) s' equals 10 cm-1) were located with millimeter resolution by scanning and detecting alterations of the ultrasound-modulated optical signal.

  1. Study of an electro-optic modulator capable of generating simultaneous amplitude and phase modulations

    CERN Document Server

    Cusack, B J; Shaddock, D A; Gray, M B; Lam, P K; Whitcomb, S E; Cusack, Benedict J; Gray, Malcolm B; Lam, Ping Koy; Shaddock, Daniel A; Sheard, Benjamin S; Whitcomb, Stan E

    2003-01-01

    We report on the analysis and prototype-characterization of a dual-electrode electro-optic modulator that can generate both amplitude and phase modulations with a selectable relative phase, termed a universally tunable modulator (UTM). All modulation states can be reached by tuning only the electrical inputs, facilitating real-time tuning, and the device is shown to have good suppression and stability properties. A mathematical analysis is presented, including the development of a geometric phase representation for modulation. The experimental characterization of the device shows that relative suppressions of 38 dB, 39 dB and 30 dB for phase, single-sideband and carrier-suppressed modulations, respectively, can be obtained, as well as showing the device is well-behaved when scanning continuously through the parameter space of modulations. Uses for the device are discussed, including the tuning of lock points in optical locking schemes, single sideband applications, modulation fast-switching applications, and ...

  2. Optical signal processing using electro-absorption modulators

    DEFF Research Database (Denmark)

    Mørk, Jesper; Romstad, Francis Pascal; Højfeldt, Sune;

    2003-01-01

    Reverse-biased semiconductor waveguides are efficient saturable absorbers and have a number of promising all-optical signal processing applications. Results on ultrafast modulator dynamics as well as demonstrations and investigations of wavelength conversion and regeneration are presented....

  3. A capillary optical fiber modulator derivates from magnetic fluid

    Science.gov (United States)

    Yang, Xinghua; Liu, Yanxin; Zheng, Yao; Li, Shouzhu; Yuan, Libo; Yuan, Tingting; Tong, Chengguo

    2013-09-01

    A novel in-fiber integrated modulator based on magnetic fluid is proposed. The Fe3O4 magnetic fluid is encapsulated into a specially designed capillary optical fiber with a circular waveguide. Experimental results show that the light at 632.8 nm in the circular waveguide can be modulated by only 2.17×10-2 μL of the magnetic fluid under magnetic field. A wide range of modulation-depth from 44% to 75% can be obtained by adjusting the external magnetic field strength, temperature and the concentration of the magnetic fluid. In addition, the modulator shows good stability and repeatability. This work has great potentials in the integrated optical devices such as tunable in-fiber modulators, optical switches and magnetic sensors.

  4. Optical modulator based on coupled photonic crystal cavities

    Science.gov (United States)

    Serafimovich, Pavel G.; Kazanskiy, Nikolay L.

    2016-07-01

    We propose and numerically investigate an optical signal modulator based on two-photonic crystal nanobeam cavities coupled through a waveguide. The suggested modulator shifts the resonant frequency over a scalable range. We design a compact optical modulator based on photonic crystal nanobeams cavities that exhibits high stability to manufacturing. Photonic crystal waveguide tuning in the low-intensity region of the resonant mode is demonstrated. The advantages of the suggested approach over the single-resonator optical modulator approaches include the possibilities to shift the modulator frequency over a scalable range that depends on switching energy level and to effectively electrically tune the device in the low-intensity region of the resonant mode.

  5. Optical modulation in a resonant tunneling relaxation oscillator

    OpenAIRE

    Figueiredo, J.M.L.; Stanley, C.R.; Boyd, A.R.; Ironside, C. N.; McMeekin, S.G.; Leite, A. M. P.

    1999-01-01

    We report high-speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band edge, small changes of the applied voltage give rise to large, high-speed electroabsorption modulation of the light. We have o...

  6. Optical modulation in a resonant tunneling relaxation oscillator

    OpenAIRE

    Figueiredo, J.M.L.; Stanley, C.R.; Boyd, A.R.; Ironside, C. N.

    2005-01-01

    We report high speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band-edge, small changes of the applied voltage give rise to large, high-speed electro-absorption modulation of the light. We have ...

  7. Quantum Hamiltonian theory of an electro-optical modulator

    Science.gov (United States)

    Miroshnichenko, G. P.; Gleim, A. V.

    2015-07-01

    A Quantum Hamiltonian formalism is proposed for the description of an electro-optical modulator based on the linear Pockels effect. Optical photons interact with photons of a microwave mode in a combined high- Q cavity made of a LiNbO3 crystal. The microwave photons occupy a coherent state, while optical photons have an arbitrary density matrix. The spectrum of a photodetected modulated signal is analyzed as a function of the frequency of a tunable optical filter. Numerical estimates are obtained, and quantum effects in the spectrum, such as the red shift of the central frequency and sidebands, the possibility of modulation of the optical signal by the microwave field vacuum, and the asymmetry of the intensity of the spectral sidebands, are discussed.

  8. High-speed waveguide electro-optic polarization modulator.

    Science.gov (United States)

    Alferness, R C; Buhl, L L

    1982-10-01

    By careful electrode design we have achieved a 1.7-GHz modulation bandwidth for a Ti:LiNbO(3) integrated-optic TE ? TM mode-converter modulator. Because of the wavelength selectivity of this modulator, it is an attractive device for simultaneously providing multiplexing and signal encoding in future wavelength-multiplexed single-mode light-wave systems. PMID:19714070

  9. All-optical Demultiplexing Using an Electroabsorption Modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    1999-01-01

    In the last decade, the electroabsorption modulator (EAM) (essentially a reverse biased semiconductor optical amplifier) has found an increasingly wider range of applications within optical communications, although mostly at the research level. Recently, all-optical signal-processing such as wave......In the last decade, the electroabsorption modulator (EAM) (essentially a reverse biased semiconductor optical amplifier) has found an increasingly wider range of applications within optical communications, although mostly at the research level. Recently, all-optical signal-processing...... the channel to be demultiplexed, and the other OTDM channels is shown to saturate at a value which increases with the signal input power....... such as wavelength conversion, demultiplexing, and signal regeneration using an EAM have also been experimentally demonstrated, and lately theoretical calculations of wavelength conversion and signal regeneration have been presented. These functionalities are important for constructing ultrahigh-speed all...

  10. Hybrid silicon-vanadium dioxide electro-optic modulators

    Science.gov (United States)

    Miller, Kevin J.; Markov, Petr; Marvel, Robert E.; Haglund, Richard F.; Weiss, Sharon M.

    2016-03-01

    Small-footprint, low-power devices that can modulate optical signals at THz speeds would transform next-generation onchip photonics. We describe a hybrid silicon-vanadium dioxide (Si-VO2) electro-optic ring resonator modulator as a candidate platform for achieving this performance benchmark. Vanadium dioxide (VO2) is a strongly correlated material exhibiting a semiconductor-to-metal transition (SMT) accompanied by large changes in electrical and optical properties. While VO2 can be switched optically on a sub-picosecond time scale, the ultimate electrical switching speed remains to be determined. In a 5 μm radius Si-VO2 ring resonator, we achieve 1.5 dB modulation in response to a 10 ns square voltage pulse of 2.5 V. In the steady state regime, we report a modulation depth of 10 dB. The larger modulation depth at longer timescales is attributed to a Joule heating contribution. Experimental results, corroborated by FDTD simulations, reveal the relationship between the portion of a VO2 patch undergoing the SMT and the resulting effects on the Si-VO2 device performance. This work indicates that with further reduction of VO2 patch sizes and increase in resonator Q factor, there is promise for the Si-VO2 ring resonator electro-optic modulator as a competitive option for on-chip photonics technology.

  11. Performance Study of optical Modulator based on electrooptic effect

    Science.gov (United States)

    Palodiya, V.; Raghuwanshi, S. K.

    2016-08-01

    In this paper, we have studied and derive performance parameter of highly integrated Lithium Niobate optical modulator. This is a chirp free modulator having low switching voltage and large bandwidth. For an external modulator in which travelling-wave electrodes length L imposed the modulating switching voltage, the product of Vπ and L is fixed for a given electro optic material Lithium Niobate. We investigate to achieve a low Vπ by both magnitude of the electro-optic coefficient for a wide variety of electro-optic materials. A Sellmeier equation for the extraordinary index of congruent lithium niobate is derived. For phase-matching, predictions are accmate for temperature between room temperature 250°C and wavelength ranging from 0.4 to 5µm. The Sellmeier equations predict more accmately refractive indices at long wavelengths. Theoretical result is confirmed by simulated results. We have analysed the various parameters such as switching voltage, device performance index, time constant, transmittance, cut-off frequency, 3-dB bandwidth, power absorption coefficient and transmission bit rate of Lithium Niobate optical Modulator based on electro -optic effect.

  12. Optical modulation in a resonant tunneling relaxation oscillator

    CERN Document Server

    Figueiredo, J M L; Boyd, A R; Ironside, C N

    1999-01-01

    We report high speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band-edge, small changes of the applied voltage give rise to large, high-speed electro-absorption modulation of the light. We have observed optical modulation at frequencies up to 14 GHz, associated with sub harmonic injection locking of the RTD oscillation at the fundamental mode of the coplanar transmission line, as well as generation of 33 ps optical pulses due to relaxation oscillation.

  13. High-power high-efficiency acousto-optically Q-switched rod Nd:YAG laser with 885 nm diode laser pumping

    Science.gov (United States)

    Liu, K.; Li, F. Q.; Xu, H. Y.; Wang, Z. C.; Zong, N.; Du, S. F.; Bo, Y.; Peng, Q. J.; Cui, D. F.; Xu, Z. Y.

    2013-01-01

    We have demonstrated a compact Q-switched Nd:YAG laser at 1064 nm with 885 nm diode-laser (LD) direct pumping. At a repetition rate of 100 kHz, an average output power of 53 W with beam quality factor M2 of 1.6 was achieved under the absorbed pump power of 122 W, corresponding to an optical-optical efficiency of 43.5% and a slope efficiency of 57.6%, respectively. The pulse width and the peak power at this output power were 112 ns and 4.74 kW, respectively.

  14. OPTICAL WAVELENGTH CONVERTERS BASED ON CROSS GAIN MODULATION AND CROSS PHASE MODULATION IN SOA

    Directory of Open Access Journals (Sweden)

    Vikas Thakur

    2012-06-01

    Full Text Available All optical wavelength conversion is demonstrated at 10 Gbit/s over a wavelength span of 10 nm without any bit loss by the use of Semiconductor Optical Amplifier (SOA in a Mach-Zehnder configuration. These wavelength conversion architectures are implemented by using SOA cross-gain modulation (XGM and cross-phase modulation (XPM techniques. We have compared the results of both techniques on the basics of Bit Error Rate (BER and Quality factor.

  15. Subpicosecond-pulse generation through cross-phase-modulation-induced modulational instability in optical fibers.

    Science.gov (United States)

    Gouveia-Neto, A S; Faldon, M E; Sombra, A S; Wigley, P G; Taylor, J R

    1988-10-01

    We report subpicosecond-pulse generation at 1.319 microm in a single-mode optical fiber by modulational instability induced through cross-phase modulation by 1.06-microm pulses propagating in the normal dispersion regime. Pulse-repetition rates approaching 300 GHz were achieved.

  16. Optical Frequency-Modulated Continuous-Wave (FMCW) Interferometry

    CERN Document Server

    Zheng, Jesse

    2005-01-01

    This book introduces the optical frequency-modulated continuous-wave (FMCW) interferometry - a new field of optics that is derived from radar. The study of optical FMCW interference not only updates our knowledge about the nature of light, but also creates an advanced technology for precision measurements. The principles, applications and signal processing of optical FMCW interference are systematically discussed. This book is intended for scientists and engineers in both academia and industry. It is especially suited to professionals who are working in the field of measurement instruments.

  17. Wide and stable optical frequency comb in an intensity-modulated continuous wave pumped optical fiber

    International Nuclear Information System (INIS)

    This paper investigates how to obtain a wide and stable optical frequency comb in an intensity-modulated continuous-wave pumped optical fiber by straightforwardly characterizing the signal-to-noise ratio and analyzing the optimal fiber length. The stability of the obtained optical frequency comb is analyzed by a method which is similar to the eye pattern. The prospect for obtaining wider and more stable optical frequency combs is discussed. (paper)

  18. All-optical microwave signal processing based on optical phase modulation

    Science.gov (United States)

    Zeng, Fei

    This thesis presents a theoretical and experimental study of optical phase modulation and its applications in all-optical microwave signal processing, which include all-optical microwave filtering, all-optical microwave mixing, optical code-division multiple-access (CDMA) coding, and ultrawideband (UWB) signal generation. All-optical microwave signal processing can be considered as the use of opto-electronic devices and systems to process microwave signals in the optical domain, which provides several significant advantages such as low loss, low dispersion, light weight, high time bandwidth products, and immunity to electromagnetic interference. In conventional approaches, the intensity of an optical carrier is modulated by a microwave signal based on direct modulation or external modulation. The intensity-modulated optical signal is then fed to a photonic circuit or system to achieve specific signal processing functionalities. The microwave signal being processed is usually obtained based on direct detection, i.e., an opto-electronic conversion by use of a photodiode. In this thesis, the research efforts are focused on the optical phase modulation and its applications in all-optical microwave signal processing. To avoid using coherent detection which is complicated and costly, simple and effective phase modulation to intensity modulation (PM-IM) conversion schemes are pursued. Based on a theoretical study of optical phase modulation, two approaches to achieving PM-IM conversions are proposed. In the first approach, the use of chromatic dispersion induced by a dispersive device to alter the phase relationships among the sidebands and the optical carrier of a phase-modulated optical signal to realize PM-IM conversion is investigated. In the second approach, instead of using a dispersive device, the PM-IM conversion is realized based on optical frequency discrimination implemented using an optical filter. We show that the proposed PM-IM conversion schemes can be

  19. Connection cube modules for optical backplanes and fiber networks.

    Science.gov (United States)

    Kostuk, R K; Ramsey, D L; Kim, T J

    1997-07-10

    A modular free-space optical system, called the connection cube, for connecting arrays of electro-optic transceivers and fiber-array connectors is presented. The connection cube module provides bidirectional data transfer between four processing nodes on a cube face and can be used as a basic building block for optical backplanes and interconnect networks. An experimental system for connecting four processing nodes is presented and used to examine alignment and packaging issues. An analysis of the dimensional requirements and scaling capability for systems based on this module is conducted. This analysis shows that, when the connection cube module is adapted to vertical-cavity surface-emitting-laser-based point-to-point fiber-array links currently under development, it can connect up to 14 processing nodes with an aggregate data transfer capacity of 112 Gbits/s with 19.6-W power consumption. PMID:18259270

  20. High Frequency Acousto-electric Single Photon Source

    CERN Document Server

    Foden, C L; Milburn, G J; Leadbeater, M L; Pepper, M

    2000-01-01

    We propose a single optical photon source for quantum cryptography based on the acousto-electric effect. Surface acoustic waves (SAWs) propagating through a quasi-one-dimensional channel have been shown to produce packets of electrons which reside in the SAW minima and travel at the velocity of sound. In our scheme these electron packets are injected into a p-type region, resulting in photon emission. Since the number of electrons in each packet can be controlled down to a single electron, a stream of single (or N) photon states, with a creation time strongly correlated with the driving acoustic field, should be generated.

  1. Silicon Modulators, Switches and Sub-systems for Optical Interconnect

    Science.gov (United States)

    Li, Qi

    Silicon photonics is emerging as a promising platform for manufacturing and integrating photonic devices for light generation, modulation, switching and detection. The compatibility with existing CMOS microelectronic foundries and high index contrast in silicon could enable low cost and high performance photonic systems, which find many applications in optical communication, data center networking and photonic network-on-chip. This thesis first develops and demonstrates several experimental work on high speed silicon modulators and switches with record performance and novel functionality. A 8x40 Gb/s transmitter based on silicon microrings is first presented. Then an end-to-end link using microrings for Binary Phase Shift Keying (BPSK) modulation and demodulation is shown, and its performance with conventional BPSK modulation/ demodulation techniques is compared. Next, a silicon traveling-wave Mach- Zehnder modulator is demonstrated at data rate up to 56 Gb/s for OOK modulation and 48 Gb/s for BPSK modulation, showing its capability at high speed communication systems. Then a single silicon microring is shown with 2x2 full crossbar switching functionality, enabling optical interconnects with ultra small footprint. Then several other experiments in the silicon platform are presented, including a fully integrated in-band Optical Signal to Noise Ratio (OSNR) monitor, characterization of optical power upper bound in a silicon microring modulator, and wavelength conversion in a dispersion-engineered waveguide. The last part of this thesis is on network-level application of photonics, specically a broadcast-and-select network based on star coupler is introduced, and its scalability performance is studied. Finally a novel switch architecture for data center networks is discussed, and its benefits as a disaggregated network are presented.

  2. SOI thermo-optic modulator with fast response

    Institute of Scientific and Technical Information of China (English)

    Xiaolong Wang(王小龙); Jingwei Liu(刘敬伟); Qingfeng Yan(严清峰); Shaowu Chen(陈绍武); Jinzhong Yu(余金中)

    2003-01-01

    Silicon-on-insulator (SOI) technology offers tremendous potential for integration of optoelectronic functionson a silicon wafer. In this letter, a 1 × 1 multimode interference (MMI) Mach-Zender interferometer(MZI) thermo-optic modulator fabricated by wet-etching method is demonstrated. The modulator has anextinction ratio of -11.0 dB, extra loss of -4.9 dB and power consumption of 420 mW. The response timeis less than 30μs.

  3. Analytical analysis of modulation instability in fiber optics

    Directory of Open Access Journals (Sweden)

    M. Saeed Aslam

    2012-06-01

    Full Text Available In this paper, an improved analysis for modulation instability, which results from interaction between optical wave and noise, is presented. It is shown that Nonlinear Schrodinger equation (NLSE, which governs this process, leads to the coupled wave equations that result to Riccati's differential equations. A completely analytical solution of Riccati's equation is obtained for small fiber length that results in efficient computation of the modulation instability effect.

  4. Design of multimode interference optical switches with area modulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the self-imaging effect, multimode interference (MMI) optical switches with area modulation were proposed. The field transfer matrix was introduced to analyze the MMI switches. As an example, the phase modulation parameters of a 3 × 3 MMI switch for different switching cases were obtained by solving the field transfer equation. And the finite-difference beam propagation method (FD-BPM) was used to confirm the analytical results.

  5. Radiometric modulation measuring device of intensity of optical radiation

    Directory of Open Access Journals (Sweden)

    A. P. Yanenko

    2014-04-01

    Full Text Available Introduction. The paper proposed a block diagram of radiometric measuring the intensity of optical radiation from modulation conversion parameter input . To assess the intensity of use periodically comparing the reference signal (shaded and measurement (open photodi-odes. Studies. The proposed radiometric modulation meter provides increased sensitivity and measurement accuracy by reducing the influence of dark current measurement and reference photodiodes and compensation intrinsic noise measuring channel through their periodic anti-phase comparison.

  6. Extreme Universe Space Observatory (EUSO) Optics Module

    Science.gov (United States)

    Young, Roy; Christl, Mark

    2008-01-01

    A demonstration part will be manufactured in Japan on one of the large Toshiba machines with a diameter of 2.5 meters. This will be a flat PMMA disk that is cut between 0.5 and 1.25 meters radius. The cut should demonstrate manufacturing the most difficult parts of the 2.5 meter Fresnel pattern and the blazed grating on the diffractive surface. Optical simulations, validated with the subscale prototype, will be used to determine the limits on manufacturing errors (tolerances) that will result in optics that meet EUSO s requirements. There will be limits on surface roughness (or errors at high spatial frequency); radial and azimuthal slope errors (at lower spatial frequencies) and plunge cut depth errors in the blazed grating. The demonstration part will be measured to determine whether it was made within the allowable tolerances.

  7. Polymer Electro-optic Modulator Linear Bias Using the Thermo-optic Effect

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-Qiang; CHEN Chang-Ming; LI Xiao-Dong; WANG Xi-Bin; YANG Tian-Fu; ZHANG Da-Ming; WANG Fei; XIE Zhi-Yuan

    2012-01-01

    A quasi-rectangular waveguide polymer Mach-Zehnder (M-Z) electro-optic (EO) modulator based on an organic/inorganic hybrid material with thermal bias control is fabricated and demonstrated. Linear bias for the modulator is obtained through thermo-optic effect. The optical output is adjusted by changing phase difference between the two arms of the M-Z interferometer. A power consumption of 16.1 mW for π phase change is observed owing to the application of silica cladding. This approach is proved to be effective to suppress direct current drift in polymer EO modulators.%A quasi-rectangular waveguide polymer Mach-Zehnder (M-Z) electro-optic (EO) modulator based on an organic/inorganic hybrid material with thermal bias control is fabricated and demonstrated.Linear bias for the modulator is obtained through thermo-optic effect.The optical output is adjusted by changing phase difference between the two arms of the M-Z interferometer.A power consumption of 16.1 m W for π phase change is observed owing to the application of silica cladding.This approach is proved to be effective to suppress direct current drift in polymer EO modulators.

  8. Dynamic behavior and complexity of modulated optical micro ring resonator

    Institute of Scientific and Technical Information of China (English)

    Lei Yang; Wei Pan; Bin Luo; ShuiYing Xiang; Ning Jiang

    2011-01-01

    @@ The dynamic behavior of an optical micro ring resonator (OMRR) with an amplitude modulator positioned in the micro ring is investigated quantitatively by adopting a recently introduced quantifier, the permutation entropy (PE).The effects of modulation depth are focused on, and the roles of input power are considered.The two-dimensional (2D) maps of PE showing dependence on both modulation depth and input power are presented as well.PE values nearly increase with modulation depth.On the other hand, the optimal value of input power is achieved when the PE reaches its maximum.Thus, PE can successfully quantify the dynamics of modulated OMRR.Selecting the parameters in the region with high PE values would contribute to the complexity-enhanced OMRR-based chaotic communication systems.%The dynamic behavior of an optical micro ring resonator (OMRR) with an amplitude modulator positioned in the micro ring is investigated quantitatively by adopting a recently introduced quantifier, the permutation entropy (PE). The effects of modulation depth are focused on, and the roles of input power are considered. The two-dimensional (2D) maps of PE showing dependence on both modulation depth and input power are presented as well. PE values nearly increase with modulation depth. On the other hand, the optimal value of input power is achieved when the PE reaches its maximum. Thus, PE can successfully quantify the dynamics of modulated OMRR. Selecting the parameters in the region with high PE values would contribute to the complexity-enhanced OMRR-based chaotic communication systems.

  9. 20-GHz optical pulse source based on cascaded electroabsorption modulators

    Institute of Scientific and Technical Information of China (English)

    Yuanshan Liu; Jianguo Zhang; Wei Zhao

    2007-01-01

    A high-quality low-timing-jitter 20-GHz optical pulse train is generated by using two cascaded sinusoidally driven electroabsorption modulators (EAMs) at very low bias voltage of -0.8 V in conjunction with a tunable distributed feedback (DFB) semiconductor laser. An approximate transform-limited optical pulse,with the pulse width less than 7 ps, the spectral width of 0.3 nm, and the side-mode suppression ratio (SMSR) above 20 dB, is obtained by tuning the optical delay line.

  10. Frequency modulation via the Doppler effect in optical fibers.

    Science.gov (United States)

    Oberson, P; Huttner, B; Gisin, N

    1999-04-01

    We present the principle of optical frequency modulation via the Doppler effect obtained by rapidly stretching an optical fiber and thus modifying the optical path of the light propagating in the fiber. This procedure creates a pure frequency shift, with no degradation of the spectrum. Moreover, the effect is wavelength independent and can therefore be applied to any type of light source. We show an experimental realization in which a frequency excursion of ~100 MHz was obtained with a bobbin vibrating at 180 Hz.

  11. Optical modulation of terahertz pulses in a parallel plate waveguide

    DEFF Research Database (Denmark)

    Cooke, David; Jepsen, Peter Uhd

    2008-01-01

    In this work we present a technique for optically modulating a terahertz pulse inside a parallel plate waveguide. A novel semiconductor filled waveguide is formed by coating both sides of a thin, high resistivity silicon slab with a transparent conducting oxide. While the waveguide is intrinsically...

  12. Comprehensive research on self phase modulation based optical delay systems

    International Nuclear Information System (INIS)

    This paper comprehensively investigates the properties of self phase modulation based optical delay systems consisting of dispersion compensation fibre and highly nonlinear fibres. It researches into the impacts of power level launched into highly nonlinear fibres, conversion wavelength, dispersion slope, modulation format and optical filter bandwidth on the overall performance of optical delay systems. The results reveal that, if the power launched into highly nonlinear fibres is fixed, the time delay generally varies linearly with the conversion wavelength, but jumps intermittently at some conversion wavelengths. However, the time delay varies semi-periodically with the power launched into highly nonlinear fibres. The dispersion slope of highly nonlinear fibres has significant influence on the time delay, especially for the negative dispersion slope. The time delay differs with modulation formats due to the different combined interaction of nonlinearity and dispersion in fibres. The bandwidth of the optical filters also greatly affects the time delay because it determines the bandwidth of the passed signal in the self phase modulation based time delay systems. The output signal quality of the overall time delay systems depends on the conversion wavelength and input power level. The optimisation of the power level and conversion wavelength to provide the best output signal quality is made at the end of this paper

  13. The KM3NeT Digital Optical Module

    Science.gov (United States)

    Vivolo, Daniele

    2016-04-01

    KM3NeT is a European deep-sea multidisciplinary research infrastructure in the Mediterranean Sea. It will host a km3-scale neutrino telescope and dedicated instruments for long-term and continuous measurements for Earth and Sea sciences. The KM3NeT neutrino telescope is a 3-dimensional array of Digital Optical Modules, suspended in the sea by means of vertical string structures, called Detection Units, supported by two pre-stretched Dyneema ropes, anchored to the seabed and kept taut with a system of buoys. The Digital Optical Module represents the active part of the neutrino telescope. It is composed by a 17-inch, 14 mm thick borosilicate glass (Vitrovex) spheric vessel housing 31 photomultiplier tubes with 3-inch photocathode diameter and the associated front-end and readout electronics. The technical solution adopted for the KM3NeT optical modules is characterized by an innovative design, considering that existing neutrino telescopes, Baikal, IceCube and ANTARES, all use large photomultipliers, typically with a diameter of 8″ or 10″. It offers several advantages: higher sensitive surface (1260 cm2), weaker sensitivity to Earth's magnetic field, better distinction between single-photon and multi-photon events (photon counting) and directional information with an almost isotropic field of view. In this contribution the design and the performance of the KM3NeT Digital Optical Modules are discussed, with a particular focus on enabling technologies and integration procedure.

  14. Optical heterodyne detected velocity modulation molecular ionic spectroscopy

    Institute of Scientific and Technical Information of China (English)

    CHEN Guanglong; YANG Xiaohua; YING Xuping; LIU Gang; HUANG Yunxia; CHEN Yangqin

    2004-01-01

    Optical heterodyne detected velocity modulation molecular ionic spectroscopy is presented and employed to observe the rovibrantional spectra of and That the lineshape of OH-VMS is of the second derivative of Gaussian profile and its sensitivity is 3.5×10-8 are theoretically analyzed, and they are both in good agreement with our experimental results.

  15. Comprehensive research on self phase modulation based optical delay systems

    Institute of Scientific and Technical Information of China (English)

    Yang Ai-Ying; Sun Yu-Nan

    2010-01-01

    This paper comprehensively investigates the properties of self phase modulation based optical delay systems consisting of dispersion compensation fibre and highly nonlinear fibres.It researches into the impacts of power level launched into highly nonlinear fibres,conversion wavelength,dispersion slope,modulation format and optical filter bandwidth on the overall performance of optical delay systems.The results reveal that,if the power launched into highly nonlinear fibres is fixed,the time delay generally varies linearly with the conversion wavelength,but jumps intermittently at some conversion wavelengths.However,the time delay varies semi-periodically with the power launched into highly nonlinear fibres.The dispersion slope of highly nonlinear fibres has significant influence on the time delay,especially for the negative dispersion slope.The time delay differs with modulation formats due to the different combined interaction of nonlinearity and dispersion in fibres.The bandwidth of the optical filters also greatly affects the time delay because it determines the bandwidth of the passed signal in the self phase modulation based time delay systems.The output signal quality of the overall time delay systems depends on the conversion wavelength and input power level.The optimisation of the power level and conversion wavelength to provide the best output signal quality is made at the end of this paper.

  16. Optical design of a color film recorder with PLZT modulators

    Science.gov (United States)

    Carson, John F.

    1990-08-01

    A continuous tone colour film recorder was constructed that exposes 8 x 10 inch ISO 100 daylight-balanced sheet film in ten minutes at a resolution of 1000 pixels/inch. A rotating drum is used for line scan and a leadscrew driven by a stepper motor for page scan. Film loading and unloading is automatic. Light from a stationary xenon arc lamp is split into red green and blue channel components and conducted to a translating optical system by multimode optical fiber cables. Each colour component is then modulated by a small-area PLZT light valve. An annular portion of the modulated light beam is reflected to a photodetector whose signal is used for closed-loop modulator control. The central transmitted portion of the modulated beam is combined with the other colour components into a single beam. This beam illuminates an aperture that is imaged onto the film. An overview of the mechanical electrical and optical concepts will be presented with emphasis on the optical design. 1.

  17. 30 GHz Zeno-based Graphene Electro-optic Modulator

    CERN Document Server

    Phare, Christopher T; Cardenas, Jaime; Lipson, Michal

    2014-01-01

    Graphene has generated exceptional interest as an optoelectronic material because its high carrier mobility and broadband absorption promise to make extremely fast and broadband electro-optic devices possible. Electro-optic graphene modulators reported to date, however, have been limited in bandwidth to a few GHz because of the large capacitance required to achieve reasonable voltage swings. Here we demonstrate a graphene electro-optic modulator based on the classical Zeno effect that shows drastically increased speed and efficiency. Our device operates with a 30 GHz bandwidth, over an order of magnitude faster than prior work, and a state-of-the-art modulation efficiency of 1.5 dB/V. We also show the first high-speed large-signal operation in a graphene modulator, paving the way for fast digital communications using this platform. The modulator uniquely uses silicon nitride waveguides, an otherwise completely passive material platform, with promising applications for ultra-low-loss broadband structures and n...

  18. Laser pulse spectral shaping based on electro-optic modulation

    Institute of Scientific and Technical Information of China (English)

    Yanhai Wang; Jiangfeng Wang; You'en Jiang; Yan Bao; Xuechun Li; Zunqi Lin

    2008-01-01

    A new spectrum shaping method, based on electro-optic modulation, to alleviate gain narrowing in chirped pulse amplification (CPA) system, is described and numerically simulated. Near-Fourier transform-limited seed laser pulse is chirped linearly through optical stretcher. Then the chirped laser pulse is coupled into integrated waveguide electro-optic modulator driven by an aperture-coupled-stripline (ACSL) electricalwaveform generator, and the pulse shape and amplitude are shaped in time domain. Because of the directrelationship between frequency interval and time interval of the linearly chirped pulse, the laser pulse spectrum is shaped correspondingly. Spectrum-shaping examples are modeled numerically to determine the spectral resolution of this technique. The phase error introduced in this method is also discussed.

  19. 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

  20. High speed operation of the heterostructure field effect optical modulator

    Energy Technology Data Exchange (ETDEWEB)

    Vang, T.A.; Evaldsson, P.A.; Kiely, P.A.; Taylor, G.W. [AT and T Bell Labs., Holmdel, NJ (United States); Cooke, P.W. [GEO Center Inc., Tinton Falls, NJ (United States). Fort Monmouth Operations

    1994-12-31

    The use of optical modulators in transmission systems can offer speed and chirp advantages over directly modulated semiconductor lasers. The Heterostructure Field Effect Optical Modulator (HFEOM) is a waveguide modulator that operates via band filling of quantum wells using charge transfer from an adjacent n{sup +} charge sheet. The control of this charge transfer is with a gate electrode as in a field effect transistor. The band filling of the quantum wells produces a blue-shift of the absorption edge that is used to modulate the incident light. This device is compatible in both growth and processing with the associated in-plane laser and field effect transistor. Here the authors present the initial high speed results of HFEOMs in the InGaAs/GaAs material system using a double quantum well active region. This structure has demonstrated a 35:1 extinction ratio for a 2 volt swing ({minus}1 V to + V) on a 300 {micro}m long device along with excellent wavelength compatibility with a 400 {micro}m in-plane laser fabricated from the same wafer. Capacitance limited modulation bandwidths of 1.2 GHz and 1.6 GHz are measured for 5 {micro}m and 2 {micro}m rib widths respectively.

  1. SCALE FACTOR DETERMINATION METHOD OF ELECTRO-OPTICAL MODULATOR IN FIBER-OPTIC GYROSCOPE

    Directory of Open Access Journals (Sweden)

    A. S. Aleynik

    2016-05-01

    Full Text Available Subject of Research. We propose a method for dynamic measurement of half-wave voltage of electro-optic modulator as part of a fiber optic gyroscope. Excluding the impact of the angular acceleration o​n measurement of the electro-optical coefficient is achieved through the use of homodyne demodulation method that allows a division of the Sagnac phase shift signal and an auxiliary signal for measuring the electro-optical coefficient in the frequency domain. Method. The method essence reduces to decomposition of step of digital serrodyne modulation in two parts with equal duration. The first part is used for quadrature modulation signals. The second part comprises samples of the auxiliary signal used to determine the value of the scale factor of the modulator. Modeling is done in standalone model, and as part of a general model of the gyroscope. The applicability of the proposed method is investigated as well as its qualitative and quantitative characteristics: absolute and relative accuracy of the electro-optic coefficient, the stability of the method to the effects of angular velocities and accelerations, method resistance to noise in actual devices. Main Results. The simulation has showed the ability to measure angular velocity changing under the influence of angular acceleration, acting on the device, and simultaneous measurement of electro-optical coefficient of the phase modulator without interference between these processes. Practical Relevance. Featured in the paper the ability to eliminate the influence of the angular acceleration on the measurement accuracy of the electro-optical coefficient of the phase modulator will allow implementing accurate measurement algorithms for fiber optic gyroscopes resistant to a significant acceleration in real devices.

  2. Design guideline for plasmonic 16-QAM optical modulator

    Science.gov (United States)

    Al-mfrji, Alhuda A.; Tawfeeq, Shelan K.; Fyath, Raad S.

    2016-09-01

    This paper presents the design and investigation of 16-QAM optical modulator based on plasmonic-polymer hybrid slot waveguides. The design is CMOS-compatible and uses dual-parallel Mach-Zehnder modulator (DPMZM) followed by a phase modulator (PM). Careful consideration is given to design low loss photonic-plasmonic interfaces to ensure efficient coupling between silicon and plasmonic waveguide. The effect of slot widths on device performance is investigated comprehensively using COMSOL software simulation along with analytical analysis for both gold and silver contact. The results can be used as a guideline to design compact and high speed all-plasmonic 16-QAM modulators for 1550 nm wavelength communication systems.

  3. Optical peaking enhancement in high-speed ring modulators.

    Science.gov (United States)

    Müller, J; Merget, F; Sharif Azadeh, S; Hauck, J; García, S Romero; Shen, B; Witzens, J

    2014-01-01

    Ring resonator modulators (RRM) combine extreme compactness, low power consumption and wavelength division multiplexing functionality, making them a frontrunner for addressing the scalability requirements of short distance optical links. To extend data rates beyond the classically assumed bandwidth capability, we derive and experimentally verify closed form equations of the electro-optic response and asymmetric side band generation resulting from inherent transient time dynamics and leverage these to significantly improve device performance. An equivalent circuit description with a commonly used peaking amplifier model allows straightforward assessment of the effect on existing communication system architectures. A small signal analytical expression of peaking in the electro-optic response of RRMs is derived and used to extend the electro-optic bandwidth of the device above 40 GHz as well as to open eye diagrams penalized by intersymbol interference at 32, 40 and 44 Gbps. Predicted peaking and asymmetric side band generation are in excellent agreement with experiments. PMID:25209255

  4. Optical filtering in directly modulated/detected OOFDM systems.

    Science.gov (United States)

    Sánchez, C; Ortega, B; Wei, J L; Capmany, J

    2013-12-16

    This work presents a theoretical investigation on the performance of directly modulated/detected (DM/DD) optical orthogonal frequency division multiplexed (OOFDM) systems subject to optical filtering. The impact of both linear and nonlinear distortion effects are taken into account to calculate the effective signal-to-noise ratio of each subcarrier. These results are then employed to optimize the design parameters of two simple optical filtering structures: a Mach Zehnder interferometer and a uniform fiber Bragg grating, leading to a significant optical power budget improvement given by 3.3 and 3dB, respectively. These can be further increased to 5.5 and 4.2dB respectively when balanced detection configurations are employed. We find as well that this improvement is highly dependent on the clipping ratio. PMID:24514636

  5. Evaluation of Geometrical Modulation Transfer Function in Optical Lens System

    Directory of Open Access Journals (Sweden)

    Cheng-Mu Tsai

    2015-01-01

    Full Text Available This paper presents ray tracing algorithms to evaluate the geometrical modulation transfer function (GMTF of optical lens system. There are two kinds of ray tracings methods that can be applied to help simulate the point spread function (PSF in the image plane, for example, paraxial optics and real ray tracings. The paraxial optics ray tracing is used to calculate the first-order properties such as the effective focal length (EFL and the entrance pupil position through less cost of computation. However, the PSF could have a large tolerance by only using paraxial optics ray tracing for simulation. Some formulas for real ray tracing are applied in the sagittal and tangential line spread function (LSF. The algorithms are developed to demonstrate the simulation of LSF. Finally, the GMTF is evaluated after the fast Fourier transform (FFT of the LSF.

  6. Modulator-Based, High Bandwidth Optical Links for HEP Experiments

    CERN Document Server

    Underwood, D G; Fernando, W S; Stanek, R W

    2012-01-01

    As a concern with the reliability, bandwidth and mass of future optical links in LHC experiments, we are investigating CW lasers and light modulators as an alternative to VCSELs. These links will be particularly useful if they utilize light modulators which are very small, low power, high bandwidth, and are very radiation hard. We have constructed a test system with 3 such links, each operating at 10 Gb/s. We present the quality of these links (jitter, rise and fall time, BER) and eye mask margins (10GbE) for 3 different types of modulators: LiNbO3-based, InP-based, and Si-based. We present the results of radiation hardness measurements with up to ~1012 protons/cm2 and ~65 krad total ionizing dose (TID), confirming no single event effects (SEE) at 10 Gb/s with either of the 3 types of modulators. These optical links will be an integral part of intelligent tracking systems at various scales from coupled sensors through intra-module and off detector communication. We have used a Si-based photonic transceiver to...

  7. Optical pulse compression reflectometry based on single-sideband modulator driven by electrical frequency-modulated pulse

    Science.gov (United States)

    Zou, Weiwen; Yu, Lei; Yang, Shuo; Chen, Jianping

    2016-05-01

    We propose a novel scheme to generate a linear frequency-modulated optical pulse with high extinction ratio based on an electrical frequency-modulated pulse and optical single-sideband modulator. This scheme is proved to improve the stability and accuracy of optical pulse compression reflectometry (OPCR). In the experiment, a high spatial resolution of 10 cm and a long measurement range of 10.8 km using a laser source with 2-km coherence length are demonstrated.

  8. Optical metrology for advanced process control: full module metrology solutions

    Science.gov (United States)

    Bozdog, Cornel; Turovets, Igor

    2016-03-01

    Optical metrology is the workhorse metrology in manufacturing and key enabler to patterning process control. Recent advances in device architecture are gradually shifting the need for process control from the lithography module to other patterning processes (etch, trim, clean, LER/LWR treatments, etc..). Complex multi-patterning integration solutions, where the final pattern is the result of multiple process steps require a step-by-step holistic process control and a uniformly accurate holistic metrology solution for pattern transfer for the entire module. For effective process control, more process "knobs" are needed, and a tighter integration of metrology with process architecture.

  9. Ultrasound-Modulated Optical Tomography in Reflective and Coaxial Configuration

    Institute of Scientific and Technical Information of China (English)

    傅洪波; 邢达; 曾亚光; 王毅; 陈群

    2003-01-01

    Ultrasound-modulated optical tomography affords a very promising noninvasive imaging method for biomedical diagnosis. With this technique, an ultrasound beam is focused into a scattering medium to provide an accurate localization and, simultaneously, a modulation of laser light inside the medium. Based on the high-sensitivity detection technique, we have developed a unique reflective configuration, which was more convenient and practical than other existing configurations. Furthermore, the configuration also introduced a new scheme to improve the spatial resolution in the imaging. A phantom was imaged to validate the feasibility of the proposed configuration.

  10. Interactive online optics modules for the college physics course

    Science.gov (United States)

    Hoeling, Barbara M.

    2012-04-01

    A new learning tool for geometrical optics is presented which has been developed for an algebra based introductory college physics course for life science majors. The interactive online learning module contains images, videos of problem solutions, short animated videos, and interactive animations, which allow students to actively explore the physics content beyond the pictures in a textbook. These elements are accompanied by narration and a transcript to guide the students while allowing them to navigate freely between the different parts of the module. The results of student learning, a comparison with a control group, and a survey of student attitudes toward this new instruction method are discussed.

  11. Photon counts modulation in optical time domain reflectometry

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Bo; Wang Jing-Jing; Zhang Guo-Feng; Xiao Lian-Tuan; Jia Suo-Tang

    2011-01-01

    The quantum fluctuation of photon counting limits the field application of optical time domain reflection. A method of photon counts modulation optics time domain reflection with single photon detection at 1.55 un is presented. The influence of quantum fluctuation can be effectively controlled by demodulation technology since quantum fluctuation shows a uniform distribution in the frequency domain. Combined with the changing of the integration time of the lock-in amplifier, the signal to noise ratio is significantly enhanced. Accordingly the signal to noise improvement ratio reaches 31.7 dB compared with the direct photon counting measurement.

  12. Phase-coherent orthogonally polarized optical single sideband modulation with arbitrarily tunable optical carrier-to-sideband ratio.

    Science.gov (United States)

    Wang, Wen Ting; Liu, Jian Guo; Mei, Hai Kuo; Zhu, Ning Hua

    2016-01-11

    We propose and experimentally verify a novel approach to achieve phase-coherence orthogonally polarized optical single sideband (OSSB) modulation with a tunable optically carrier-to-sideband ratio (OCSR). In our scheme, the orthogonally polarized OSSB signal is achieved using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator without an optical band-pass filter (OBPF). Therefore, the proposed method is wavelength independent. The DP-QPSK modulator includes two parallel QPSK modulators locating on its two arms. The upper QPSK modulator of the DP-QPSK modulator is driven by two quadrature sinusoidal microwave signals and works at the frequency shifting condition whose bias voltages are optimized to suppress the optical. The lower QPSK modulator of that works at the maximum transmission point and the optical carrier is not modulated. The OCSR is continuously tunable by simply adjusting the bias voltages of the lower modulator. The frequency shifting optical signal from the upper QPSK modulator and the optical carrier from the lower QPSK modulator are combined together at the output of the DP-QPSK modulator. The optical carrier and sideband are polarized orthogonally. The generated OSSB signals could be used to shift and code the phase of the microwave signal and generate ultra-wideband (UWB) microwave pulse. The proposed method is analyzed and experimental demonstrated. PMID:26832269

  13. Testing the precision optical calibration module for PINGU

    Energy Technology Data Exchange (ETDEWEB)

    Jurkovic, Martin; Holzapfel, Kilian [TU Muenchen, Physik-Department, Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    The Precision IceCube Next Generation Upgrade (PINGU) is primarily designed to determine the neutrino mass hierarchy. This measurement requires an accurate calibration of the detector in order to reduce systematic uncertainties. The Precision Optical Calibration Modules (POCAM) will be placed in the detector as a well calibrated artificial light source in the ice. The POCAM will be enclosed in a glass sphere identical to those used for the detector modules. To construct and simulate a prototype of the POCAM, every component needs to be analyzed by their optical characteristics and by the behavior in temperatures down to -50 C. Therefore a highly shielded an isolated environment has to be build up. We report the status of the testing environment and the hardware selected.

  14. The KM3NeT Digital Optical Module

    Directory of Open Access Journals (Sweden)

    Vivolo Daniele

    2016-01-01

    Full Text Available KM3NeT is a European deep-sea multidisciplinary research infrastructure in the Mediterranean Sea. It will host a km3-scale neutrino telescope and dedicated instruments for long-term and continuous measurements for Earth and Sea sciences. The KM3NeT neutrino telescope is a 3-dimensional array of Digital Optical Modules, suspended in the sea by means of vertical string structures, called Detection Units, supported by two pre-stretched Dyneema ropes, anchored to the seabed and kept taut with a system of buoys. The Digital Optical Module represents the active part of the neutrino telescope. It is composed by a 17-inch, 14 mm thick borosilicate glass (Vitrovex spheric vessel housing 31 photomultiplier tubes with 3-inch photocathode diameter and the associated front-end and readout electronics. The technical solution adopted for the KM3NeT optical modules is characterized by an innovative design, considering that existing neutrino telescopes, Baikal, IceCube and ANTARES, all use large photomultipliers, typically with a diameter of 8″ or 10″. It offers several advantages: higher sensitive surface (1260 cm2, weaker sensitivity to Earth's magnetic field, better distinction between single-photon and multi-photon events (photon counting and directional information with an almost isotropic field of view. In this contribution the design and the performance of the KM3NeT Digital Optical Modules are discussed, with a particular focus on enabling technologies and integration procedure.

  15. Optical Characterization of Different Thin Film Module Technologies

    Directory of Open Access Journals (Sweden)

    R. Ebner

    2015-01-01

    Full Text Available For a complete quality control of different thin film module technologies (a-Si, CdTe, and CIS a combination of fast and nondestructive methods was investigated. Camera-based measurements, such as electroluminescence (EL, photoluminescence (PL, and infrared (IR technologies, offer excellent possibilities for determining production failures or defects in solar modules which cannot be detected by means of standard power measurements. These types of optical measurement provide high resolution images with a two-dimensional distribution of the characteristic features of PV modules. This paper focuses on quality control and characterization using EL, PL, and IR imaging with conventional cameras and an alternative excitation source for the PL-setup.

  16. Generalized model for all-optical light modulation in bacteriorhodopsin

    Science.gov (United States)

    Roy, Sukhdev; Singh, C. P.; Reddy, K. P. J.

    2001-10-01

    We present a generalized model for the photochemical cycle of bacteriorhodopsin (bR) protein molecule. Rate equations have been solved for the detailed light-induced processes in bR for its nine states: B→K↔L↔MI→MII↔N↔O↔P→Q→B. The complete steady-state intensity-induced population densities in various states of the molecule have been computed to obtain a general, exact, and analytical expression for the nonlinear absorption coefficient for multiple modulation pump laser beams. All-optical light modulation of different probe laser beam transmissions by intensity induced population changes due to one and two modulation laser beams has been analyzed. The proposed model has been shown to accurately model experimental results.

  17. Breaking the cavity linewidth limit of resonant optical modulators

    CERN Document Server

    Sacher, Wesley D; Assefa, Solomon; Barwicz, Tymon; Pan, Huapu; Shank, Steven M; Vlasov, Yurii A; Poon, Joyce K S

    2012-01-01

    Microring optical modulators are being explored extensively for energy-efficient photonic communication networks in future high-performance computing systems and microprocessors, because they can significantly reduce the power consumption of optical transmitters via the resonant circulation of light. However, resonant modulators have traditionally suffered from a trade-off between their power consumption and maximum operation bit rate, which were thought to depend oppositely upon the cavity linewidth. Here, we break this linewidth limitation using a silicon microring. By controlling the rate at which light enters and exits the microring, we demonstrate modulation free of the parasitic cavity linewidth limitations at up to 40 GHz, more than 6x the cavity linewidth. The device operated at 28 Gb/s using single-ended drive signals less than 1.5 V. The results show that high-Q resonant modulators can be designed to be simultaneously low-power and high-speed, features which are mutually incompatible in typical reso...

  18. Applications of all optical signal processing for advanced optical modulation formats

    Science.gov (United States)

    Nuccio, Scott R.

    Increased data traffic demands, along with a continual push to minimize cost per bit, have recently motivated a paradigm shift away from traditional on-off keying (OOK) fiber transmission links towards systems utilizing more advanced modulation formats. In particular, modulation formats that utilize the phase of the optical signal, including differential phase shift keying (DPSK) and differential quadrature phase shift keying (DQPSK) along with polarization multiplexing (Pol-MUX), have recently emerged as the most popular means for transmitting information over long-haul and ultra-long haul fiber transmission systems. DPSK is motivated by an increase in receiver sensitivity compared to traditional OOK. DQPSK is motivated by a doubling of the spectral efficiency, along with increased tolerance to dispersion and nonlinear distortions. Coherent communications has also emerged as a primary means of transmitting and receiving optical data due to its support of formats that utilize both phase and amplitude to further increase the spectral efficiency (bits/sec/Hz) of the optical channel, including quadrature amplitude modulation (QAM). Polarization multiplexing of channels is a straight forward method to allow two channels to share the same wavelength by propagating on orthogonal polarization axis and is easily supported in coherent systems where the polarization tracking can be performed in the digital domain. Furthermore, the forthcoming IEEE 100 Gbit/s Ethernet Standard, 802.3ba, provides greater bandwidth, higher data rates, and supports a mixture of modulation formats. In particular, Pol-MUX (D)QPSK has grown in interest as the high spectral efficiency allows for 100 Gbit/s transmission while still occupying the current 50 GHz/channel allocation of current 10 Gbit/s OOK fiber systems. In this manner, 100 Gbit/s transfer speeds using current fiber links, amplifiers, and filters may be possible. In addition to advanced modulation formats, it is expected that optical

  19. Parallel optical interconnects utilizing VLSI/FLC spatial light modulators

    Science.gov (United States)

    Genco, Sheryl M.

    1991-12-01

    Interconnection architectures are a cornerstone of parallel computing systems. However, interconnections can be a bottleneck in conventional computer architectures because of queuing structures that are necessary to handle the traffic through a switch at very high data rates and bandwidths. These issues must find new solutions to advance the state of the art in computing beyond the fundamental limit of silicon logic technology. Today's optoelectronic (OE) technology in particular VLSI/FLC spatial light modulators (SLMs) can provide a unique and innovative solution to these issues. This paper reports on the motivations for the system, describes the major areas of architectural requirements, discusses interconnection topologies and processor element alternatives, and documents an optical arbitration (i.e., control) scheme using `smart' SLMs and optical logic gates. The network topology is given in section 2.1 `Architectural Requirements -- Networks,' but it should be noted that the emphasis is on the optical control scheme (section 2.4) and the system.

  20. Residual intensity modulation in resonator fiber optic gyros with sinusoidal wave phase modulation

    Institute of Scientific and Technical Information of China (English)

    Di-qing YING; Qiang LI; Hui-lian MA; Zhong-he JIN

    2014-01-01

    We present how residual intensity modulation (RIM) affects the performance of a resonator fiber optic gyro (R-FOG) through a sinusoidal wave phase modulation technique. The expression for the R-FOG system’s demodulation curve under RIM is obtained. Through numerical simulation with different RIM coefficients and modulation frequencies, we find that a zero deviation is induced by the RIM effect on the demodulation curve, and this zero deviation varies with the RIM coefficient and modulation frequency. The expression for the system error due to this zero deviation is derived. Simulation results show that the RIM-induced error varies with the RIM coefficient and modulation frequency. There also exists optimum values for the RIM coefficient and modulation frequency to totally eliminate the RIM-induced error, and the error increases as the RIM coefficient or modulation frequency deviates from its optimum value;however, in practical situations, these two parameters would not be exactly fixed but fluctuate from their respective optimum values, and a large system error is induced even if there exists a very small deviation of these two critical parameters from their optimum values. Simulation results indicate that the RIM-induced error should be con-sidered when designing and evaluating an R-FOG system.

  1. Polymeric Optical Code-Division Multiple-Access (CDMA Encoder and Decoder Modules

    Directory of Open Access Journals (Sweden)

    Ray T. Chen

    2011-09-01

    Full Text Available We propose a low cost polymeric optical waveguides-based optical CDMA encoder and decoder modules. The structures of the optical CDMA encoder and decoder modules are presented. The performance of the optical CDMA encoder and decoder modules is simulated using 10-chip binary phase-shift keying (BPSK coding schemes. The optical CDMA encoder and decoder modules can effectively transmit and recover optical CDMA data streams. The SNR of the received signal is analyzed and determined to be primarily from the cross correlation with other channels.

  2. Breaking the energy-bandwidth limit of electro-optic modulators: theory and a device proposal

    CERN Document Server

    Lin, Hongtao; Liu, Jifeng; Zhang, Lin; Michel, Jurgen; Hu, Juejun

    2013-01-01

    In this paper, we quantitatively analyzed the trade-off between energy per bit for switching and modulation bandwidth of classical electro-optic modulators. A formally simple energy-bandwidth limit (Eq. 10) is derived for electro-optic modulators based on intra-cavity index modulation. To overcome this limit, we propose a dual cavity modulator device which uses a coupling modulation scheme operating at high bandwidth (> 200 GHz) not limited by cavity photon lifetime and simultaneously features an ultra-low switching energy of 0.26 aJ, representing over three orders of magnitude energy consumption reduction compared to state-of-the-art electro-optic modulators.

  3. Research of transmission and reception modules of open optical communication system

    International Nuclear Information System (INIS)

    The results of studying characteristics of optical signal's transmission module's in the voltage region 3-9 V are presented. It was experimentally shown that by introducing the rectifier diode to the modulating cascade of the modulator between base and emitter the linear increase of the optical output signal is obtained. Application of double-barrier photodiode with effect of amplification of primary photocurrent with voltage provides the proper operation of receiver module from a weak optical signal. (authors)

  4. BPSK optical mm-wave signal generation by septupling frequency via a single optical phase modulator

    Science.gov (United States)

    Wu, Peng; Ma, Jianxin

    2016-09-01

    In this paper, we have proposed a novel and simple scheme to generate the BPSK optical millimeter wave (MMW) signal with frequency septupling by using an optical phase modulator (PM) and a wavelength selective switch (WSS). In this scheme, the PM is driven by a radio frequency (RF) BPSK signal at the optimized modulation index of 4.89 to assure the 4th and 3rd-order sidebands have equal amplitudes. An wavelength selective switch (WSS) is used to abstract the -4th and +3rd-order sidebands from the spectrum generated by RF BPSK signal modulating the lightwave to form the BPSK optical MMW signal with frequency septupling the driving RF signal. In these two tones, only the +3rd-order sideband bears the BPSK signal while the -4th-order sideband is unmodulated since the phase information is canceled by the even times multiplication of the phase of BPSK signal. The MMW signal can avoid the pulse walk-off effect and the amplitude fading effect caused by the fiber chromatic dispersion. By adjusting the modulation index to assure the two tones have equal amplitude, the generated optical MMW signal has the maximal opto-electrical conversion efficiency and good transmission performance.

  5. Simulation and Optimization of MQW based optical modulator for on chip optical interconnect

    Directory of Open Access Journals (Sweden)

    Sumita Mishra

    2011-05-01

    Full Text Available Optical interconnects are foreseen as a potential solution to improve the performance of data transmission in high speed integrated circuits since electrical interconnects operating at high bit rates have several limitations which creates a bottleneck at the interconnect level. The objective of the work is to model and then simulate the MQWM based optical interconnect transmitter. The power output of the simulated modulator is then optimized with respect to various parameters namely contrast ratio, insertion loss and bias current. The methodology presented here is suitable for investigation of both analog and digital modulation performance but it primarily deals with digital modulation. We have not included the effect of carrier charge density in multiple quantum well simulation.

  6. An investigation of the influence of residual amplitude modulation in phase electro-optic modulator on the signal of fiber-optic gyroscope

    Science.gov (United States)

    Pogorelaya, D. A.; Smolovik, M. A.; Strigalev, V. E.; Aleynik, A. S.; Deyneka, I. G.

    2016-08-01

    The investigation is devoted to residual amplitude modulation (RAM) of phase electro-optic modulator, which guides are made in LiNbO3 crystal by Ti diffusion technology. An analysis is presented that shows influence of RAM on the signal of fiber-optic gyroscope. The RAM compensation method is offered.

  7. Electroabsorption modulators used for all-optical signal processing and labelling

    DEFF Research Database (Denmark)

    Xu, Lin

    2004-01-01

    This thesis concerns the applications of semiconductor components, primarily electroabsorption modulators (EAMs), in optical signal processing and labelling for future all optical communication networks. An introduction to electroabsorption modulators is given and several mechanisms that form...... and various signal-processing functions based on Polarization Shift Keying (PolSK) modulation format are demonstrated. Polarization modulation is implemented by a normal Mach Zednder Modulator operating in a special but simple way. Detection and erasure of polarization information are realised by a device...

  8. KM3NeT Digital Optical Module electronics

    Directory of Open Access Journals (Sweden)

    Real Diego

    2016-01-01

    Full Text Available The KM3NeT collaboration is currently building of a neutrino telescope with a volume of several cubic kilometres at the bottom of the Mediterranean Sea. The telescope consists of a matrix of Digital Optical Modules that will detect the Cherenkov light originated by the interaction of the neutrinos in the proximity of the detector. This contribution describes the main components of the read-out electronics of the Digital Optical Module: the Power Board, which delivers all the power supply required by the Digital Optical Molule electronics; the Central Logic Board, the main core of the read-out system, hosting 31 Time to Digital Converters with 1 ns resolution and the White Rabbit protocol embedded in the Central Logic Board Field Programmable Gate Array; the Octopus boards, that transfer the Low Voltage Digital Signals from the PMT bases to the Central Logic Board and finally the PMT bases, in charge of converting the analogue signal produced in the 31 3” PMTs into a Low Voltage Digital Signal.

  9. KM3NeT Digital Optical Module electronics

    Science.gov (United States)

    Real, Diego

    2016-04-01

    The KM3NeT collaboration is currently building of a neutrino telescope with a volume of several cubic kilometres at the bottom of the Mediterranean Sea. The telescope consists of a matrix of Digital Optical Modules that will detect the Cherenkov light originated by the interaction of the neutrinos in the proximity of the detector. This contribution describes the main components of the read-out electronics of the Digital Optical Module: the Power Board, which delivers all the power supply required by the Digital Optical Molule electronics; the Central Logic Board, the main core of the read-out system, hosting 31 Time to Digital Converters with 1 ns resolution and the White Rabbit protocol embedded in the Central Logic Board Field Programmable Gate Array; the Octopus boards, that transfer the Low Voltage Digital Signals from the PMT bases to the Central Logic Board and finally the PMT bases, in charge of converting the analogue signal produced in the 31 3" PMTs into a Low Voltage Digital Signal.

  10. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection. M.S. Thesis

    Science.gov (United States)

    Huber, Robert D.; Green, Robert E., Jr.

    1990-01-01

    The acousto-ultrasonic method has proven to be a most interesting technique for nondestructive evaluation of the mechanical properties of a variety of materials. Use of the technique or a modification thereof, has led to correlation of the associated stress wave factor with mechanical properties of both metals and composite materials. The method is applied to the nondestructive evaluation of selected fiber reinforced structural composites. For the first time, conventional piezoelectric transducers were replaced with laser beam ultrasonic generators and detectors. This modification permitted true non-contact acousto-ultrasonic measurements to be made, which yielded new information about the basic mechanisms involved as well as proved the feasibility of making such non-contact measurements on terrestrial and space structures and heat engine components. A state-of-the-art laser based acousto-ultrasonic system, incorporating a compact pulsed laser and a fiber-optic heterodyne interferometer, was delivered to the NASA Lewis Research Center.

  11. Symbol rate identification for auxiliary amplitude modulation optical signal

    Science.gov (United States)

    Wei, Junyu; Dong, Zhi; Huang, Zhiping; Zhang, Yimeng

    2016-09-01

    In this paper, we creatively propose and demonstrate a method for symbol rate identification (SRI) of auxiliary amplitude modulation (AAM) optical signal based on asynchronous delay-tap sampling (ADTS) and average magnitude difference function (AMDF). The method can accurately estimate symbol rate and has large transmission impairments tolerance. Furthermore, it can be realized in the digital signal processor (DSP) with low logical resources because of multiplication-free. In order to improve the accuracy of SRI, the peak to valley ratio (PTVR) of AMDF is introduced into our method for blind chromatic dispersion (CD) compensation. The results of the numerical simulations show that the overall maximum SRI error is smaller 0.079% for return-to-zero (RZ) on-off keying (OOK), RZ differential phase-shift keying (DPSK), RZ differential quadrature phase-shift keying (DQPSK) and RZ 16-ary quadrature amplitude modulation (QAM) with 50% duty cycles.

  12. Macular pigment optical density measured by heterochromatic modulation photometry.

    Directory of Open Access Journals (Sweden)

    Cord Huchzermeyer

    Full Text Available PURPOSE: To psychophysically determine macular pigment optical density (MPOD employing the heterochromatic modulation photometry (HMP paradigm by estimating 460 nm absorption at central and peripheral retinal locations. METHODS: For the HMP measurements, two lights (B: 460 nm and R: 660 nm were presented in a test field and were modulated in counterphase at medium or high frequencies. The contrasts of the two lights were varied in tandem to determine flicker detection thresholds. Detection thresholds were measured for different R:B modulation ratios. The modulation ratio with minimal sensitivity (maximal threshold is the point of equiluminance. Measurements were performed in 25 normal subjects (11 male, 14 female; age: 30 ± 11 years, mean ± sd using an eight channel LED stimulator with Maxwellian view optics. The results were compared with those from two published techniques - one based on heterochromatic flicker photometry (Macular Densitometer and the other on fundus reflectometry (MPR. RESULTS: We were able to estimate MPOD with HMP using a modified theoretical model that was fitted to the HMP data. The resultant MPODHMP values correlated significantly with the MPODMPR values and with the MPODHFP values obtained at 0.25° and 0.5° retinal eccentricity. CONCLUSIONS: HMP is a flicker-based method with measurements taken at a constant mean chromaticity and luminance. The data can be well fit by a model that allows all data points to contribute to the photometric equality estimate. Therefore, we think that HMP may be a useful method for MPOD measurements, in basic and clinical vision experiments.

  13. Recent Progress in Silicon Electro-optic Modulators for High Speed Applications

    Institute of Scientific and Technical Information of China (English)

    XIAO Xi; YU Jin-zhong

    2008-01-01

    Silicon-based high-speed electro-optical modulator is the key component of silicon photonics for future communiction and interconnection systems. In this paper, introduced are the optical mudulation mechanisms in silicon, reviewed are some recent progresses in high-speed silicon modulators, and analyzed are advantages and shortages of the silicon modulators of different types.

  14. Optimization of Solar Module Encapsulant Lamination by Optical Constant Determination of Ethylene-Vinyl Acetate

    Directory of Open Access Journals (Sweden)

    Bing-Mau Chen

    2015-01-01

    Full Text Available This investigation elucidates the physical properties of ethylene-vinyl acetate (EVA used in the lamination process of module encapsulation and the module performance from the optical transmission to the photoelectric power. In module encapsulation, the effects of the lamination parameters on the module performance, transmittance, and stack adhesion have been considered as they were found to influence the reliability of the module. The determination of the optical constants of EVA may serve as a nondestructive analytical method for optimizing the module encapsulation, on the basis of its effects on the optical transmittance, gel content, peel strength, and performance power.

  15. Transparent conducting oxides for electro-optical plasmonic modulators

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Boltasseva, Alexandra; Lavrinenko, Andrei V.

    2015-01-01

    combines nanoscalelight confinement and optical-speed processing of signals,has the potential to enable the next generation of hybridinformation-processing devices, which are superiorto the current photonic dielectric components in terms ofspeed and compactness. New plasmonic materials (otherthan metals......), or optical materials with metal-like behavior,have recently attracted a lot of attention due to thepromise they hold to enable low-loss, tunable, CMOScompatibledevices for photonic technologies. In this review,we provide a systematic overview of various compactoptical modulator designs that utilize a class...... of themost promising new materials as the active layer or core—namely, transparent conducting oxides. Such modulatorscan be made low-loss, compact, and exhibit high tunabilitywhile offering low cost and compatibility with existingsemiconductor technologies. A detailed analysis of differentconfigurations...

  16. An Innovative Context-Based Module to Introduce Students to the Optical Properties of Materials

    Science.gov (United States)

    Testa, I.; Lombardi, S.; Monroy, G.; Sassi, E.

    2011-01-01

    A context-based module to introduce secondary school students to the study of the optical properties of materials and geometric optics is presented. The module implements an innovative teaching approach in which the behaviour of the chosen application, in this article, the optical fibre, is iteratively explored and modelled by means of a…

  17. Novel implementations of optical switch control module and 3D-CSP for 10 Gbps active optical access system

    Science.gov (United States)

    Wakayama, Koji; Okuno, Michitaka; Matsuoka, Yasunobu; Hosomi, Kazuhiko; Sagawa, Misuzu; Sugawara, Toshiki

    2009-11-01

    We propose an optical switch control procedure for high-performance and cost-effective 10 Gbps Active Optical Access System (AOAS) in which optical switches are used instead of optical splitters in PON (Passive Optical Network). We demonstrate the implemented optical switch control module on Optical Switching Unit (OSW) with logic circuits works effectively. We also propose a compact optical 3D-CSP (Chip Scale Package) to achieve the high performance of AOAS without losing cost advantage of PON. We demonstrate the implemented 3D-CSP works effectively.

  18. Monolithically integrated quantum dot optical modulator with semiconductor optical amplifier for thousand and original band optical communication

    Science.gov (United States)

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

    2016-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed with T-band (1.0 µm waveband) and O-band (1.3 µm waveband) QD optical gain materials for Gbps-order, high-speed optical data generation. The insertion loss due to coupling between the device and the optical fiber was effectively compensated for by the SOA section. It was also confirmed that the monolithic QD-OGM/SOA device enabled >4.8 Gbps optical data generation with a clear eye opening in the T-band. Furthermore, we successfully demonstrated error-free 4.8 Gbps optical data transmissions in each of the six wavelength channels over a 10-km-long photonic crystal fiber using the monolithic QD-OGM/SOA device in multiple O-band wavelength channels, which were generated by the single QD gain chip. These results suggest that the monolithic QD-OGM/SOA device will be advantageous in ultra-broadband optical frequency systems that utilize the T+O-band for short- and medium-range optical communications.

  19. Optical beamforming networks employing phase modulation and direct detection

    Science.gov (United States)

    Xue, Xiaoxiao; Zheng, Xiaoping; Zhang, Hanyi; Zhou, Bingkun

    2011-06-01

    We propose a novel dispersion-based optical beamforming network scheme employing phase modulation and direct detection. Optical phase modulators have the advantages of simple-structure, low loss and absence of bias. Dispersion-induced phase-to-intensity conversion is utilized to facilitate direct detection. A structure of wideband dispersive device (WDD) cascaded with periodic dispersive device (PDD) is introduced to enhance the system flexibility, so that the delay adjustability and RF response can be properly designed respectively by choosing appropriate dispersions of the WDD and PDD. A concept-proof system with a wideband chirped fiber grating (CFG) as the WDD and two multiband CFGs (MCFG1 and MCFG2) as the PDD separately is built to demonstrate the basic idea. The delay tuning range is 0-1.8 ns with increment of 164.2 ps. The passband center is 30 GHz for MCFG1 and 20 GHz for MCFG2, and the fractional bandwidth is 51.8%. The shot-noise-limited spurious-free dynamic range is also analyzed and measured to be 105.7 dB ṡ Hz2/3 when the average photocurrent is 2.7 mA.

  20. MT-compatible red VCSEL module for parallel optical interconnections

    Science.gov (United States)

    Van Hove, An; Van de Putte, Koen; Naessens, Kris; Dhoedt, Bart; Baets, Roel G.; Van Daele, Peter

    2000-04-01

    In this paper we present the design, fabrication and characterization of a module which directly connectorizes a 1 by 8 red VCSEL array to a small diameter polymer optical fiber array, using a standard MT ferrule. The facets of the POF are prepared by a hot knife cutting, followed by a short polishing step. First coupling results show total losses in the range of 1.1 dB/channel for a 30 cm POF link. Optical crosstalk between adjacent channels is below -45 dB. Plastic micromachined parts surrounding the VCSEL chip ensure the correct alignment of the connector, using the connector, using the connector guiding points. The parts themselves are aligned to the chip with a n index-alignment technique, using an excimer laser ablated mastertool. In a deconnectorizable version of the module, a thin, flat glue layer on the chip acts as a window between the VCSEL chip and the MT terminated POF array. Integrated in a standard ceramic package, clear eye diagrams have been measured at 150 MHz for a 10m POF link, coupled to the VCSEL array. Further efforts on higher speed measurements using dedicated drivers, will also be presented.

  1. Acousto-Convective Drying of Pine Nuts

    Science.gov (United States)

    Zhilin, A. A.; Fedorov, A. V.

    2014-07-01

    An experimental investigation of the process of drying pine nut grains has been carried out by three methods: acousto-convective, thermoconvective, and thermal. A qualitative and a quantitative comparison of the dynamics of the processes of moisture extraction from the nut grains for the considered drying methods have been made. To elucidate the mechanism of moisture extraction from the pine nut grains, we carried out a separate investigation of the process of drying the nut shell and the kernel. The obtained experimental data on the acousto-convective drying of nuts are well described by the relaxation model, the data on the thermoconvective drying are well described by the bilinear law, and the data on the thermal drying are well described by the combined method consisting of three time steps characterized by different kinetic regimes of drying.

  2. All-optical encryption based on interleaved waveband switching modulation for optical network security.

    Science.gov (United States)

    Fok, Mable P; Prucnal, Paul R

    2009-05-01

    All-optical encryption for optical code-division multiple-access systems with interleaved waveband-switching modulation is experimentally demonstrated. The scheme explores dual-pump four-wave mixing in a 35 cm highly nonlinear bismuth oxide fiber to achieve XOR operation of the plaintext and the encryption key. Bit 0 and bit 1 of the encrypted data are represented by two different wavebands. Unlike on-off keying encryption methods, the encrypted data in this approach has the same intensity for both bit 0 and bit 1. Thus no plaintext or ciphertext signatures are observed.

  3. Open-Loop Control in Quantum Optics: Two-Level Atom in Modulated Optical Field

    OpenAIRE

    Saifullah; Borisenok, Sergei

    2008-01-01

    The methods of mathematical control theory are widely used in the modern physics, but still they are less popular in quantum science. We will discuss the aspects of control theory, which are the most useful in applications to the real problems of quantum optics. We apply this technique to control the behavior of the two-level quantum particles (atoms) in the modulated external optical field in the frame of the so called "semi classical model", where quantum two-level atomic system (all other ...

  4. All-optical demultiplexing and wavelength conversion in an electroabsorption modulator

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Hilliger, E.; Tersigni, Andrea;

    2001-01-01

    Cross-absorption modulation in an all electroabsorption modulator is utilised to perform 80/10 Gb/s all-optical demultiplexing. An improvement in receiver sensitivity at 10 Gb/s is demonstrated when wavelength converting....

  5. An optical FSK transmitter based on an integrated DFB laser-EA modulator and its application in optical labeling

    DEFF Research Database (Denmark)

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

    2003-01-01

    An optical frequency-shift-keying (FSK) transmitter based on an integrated distributed feedback laser-electroabsorption modulator is proposed and demonstrated. The feasibility of its application in optical labeling is also validated by the experimental results. The generated optical signal......, consisting of a 10-Gb/s intensity-modulated payload and a 312-Mb/s FSK label, can be recovered error free after transmission over 88-km standard single-mode fiber....

  6. Femtojoule-Scale All-Optical Latching and Modulation via Cavity Nonlinear Optics

    Science.gov (United States)

    Kwon, Yeong-Dae; Armen, Michael A.; Mabuchi, Hideo

    2013-11-01

    We experimentally characterize Hopf bifurcation phenomena at femtojoule energy scales in a multiatom cavity quantum electrodynamical (cavity QED) system and demonstrate how such behaviors can be exploited in the design of all-optical memory and modulation devices. The data are analyzed by using a semiclassical model that explicitly treats heterogeneous coupling of atoms to the cavity mode. Our results highlight the interest of cavity QED systems for ultralow power photonic signal processing as well as for fundamental studies of mesoscopic nonlinear dynamics.

  7. DSP based coherent receiver for phase-modulated radio-over-fiber optical links

    DEFF Research Database (Denmark)

    Zibar, Darko; Tafur Monroy, Idelfonso; Peucheret, Christophe;

    2008-01-01

    A novel DSP based coherent receiver for phase modulated radio-over-fiber optical links is reported. Using the proposed digital receiver, signal demodulation of 1.25 Gb/s ASK-modulated 10 GHz RF carrier is experimentally demonstrated.......A novel DSP based coherent receiver for phase modulated radio-over-fiber optical links is reported. Using the proposed digital receiver, signal demodulation of 1.25 Gb/s ASK-modulated 10 GHz RF carrier is experimentally demonstrated....

  8. Programmable logic controller optical fibre sensor interface module

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Hinckley, Steven

    2011-12-01

    Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

  9. Signal restoration in intensity-modulated optical OFDM access systems.

    Science.gov (United States)

    Vanin, Evgeny

    2011-11-15

    It is well known that deliberate signal clipping in an intensity-modulated (IM) laser transmitter helps to overcome the optical orthogonal frequency division multiplexing (OFDM) system performance limitation that is related to the signal high peak-to-average power ratio. The amplitude of a clipped OFDM signal has to be optimized in order to minimize the optical power that is required to achieve a specified system performance. However, the signal clipping introduces nonlinear distortion (so-called clipping noise) and leads to a system performance penalty. In this Letter, the performance of the IM optical OFDM system with digital baseband clipping distortion in the transmitter and clipping noise compensation by means of signal restoration in the digital signal processing unit of the system receiver is analytically evaluated. It is demonstrated that the system bit-error ratio can be reduced by more than an order of magnitude, from 10(-3) to 3.5×10(-5), by applying only the first iteration of the signal restoration algorithm proposed in this Letter. The results of the analytical analysis are verified with brute-force numerical simulations based on direct error counting. PMID:22089556

  10. Optimization design of optical waveguide in Mach-Zehnder electro-optical polymer modulator

    Institute of Scientific and Technical Information of China (English)

    GAO Yuan; ZHANG Xiao-xia; LIAO Jin-kun

    2011-01-01

    @@ In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation.The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide.The effects of structure parameters such as ridge width, length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method.The structure is optimized as an S-sine bend branch waveguide, with rib width w=7 μm, length of branch waveguide L=1200μm and interferometer spacing G=22 μm.The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.

  11. Influence of SiO2/In2O3 film acoustical waveguide on the mode index of Ti:LiNbO3 optical waveguide in acousto-optical mode converter

    Science.gov (United States)

    Lin, Hang-you; Ning, Ji-ping; Geng, Fan

    2004-04-01

    TE/TM mode converter is a key element of integrated acoustooptical tunable filter (AOTF). Employing SiO2/In2O3 film as acoustical waveguide can suppress sidelobes effectively and simplify fabrication technique in integrated quasi-collinear AOTF. In this report, the eigenvalue equation and the field solution of such configuration has been obtained by using modified Wenzel-Kramers-Brillouin (WKB) method. The results are compared with those by using vector finite element method (VFEM). When the optical waveguides are covered by such oxide film, the difference of mode indices of both polarizations and the effective propagation velocity of surface acoustical wave (SAW) will decrease, and these decreases lead the shift of optical wavelength, which mainly results in the change of the former.

  12. Fully reconfigurable 2x2 optical cross-connect using tunable wavelength switching modules

    DEFF Research Database (Denmark)

    Liu, Fenghai; Zheng, Xueyan; Pedersen, Rune Johan Skullerud;

    2001-01-01

    A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels.......A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels....

  13. Open-Loop Control in Quantum Optics: Two-Level Atom in Modulated Optical Field

    CERN Document Server

    Saifullah, Sergei

    2008-01-01

    The methods of mathematical control theory are widely used in the modern physics, but still they are less popular in quantum science. We will discuss the aspects of control theory, which are the most useful in applications to the real problems of quantum optics. We apply this technique to control the behavior of the two-level quantum particles (atoms) in the modulated external optical field in the frame of the so called "semi classical model", where quantum two-level atomic system (all other levels are neglected) interacts with classical electromagnetic field. In this paper we propose a simple model of feedforward (open-loop) control for the quantum particle system, which is a basement for further investigation of two-level quantum particle in the external one-dimensional optical field.

  14. 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.

  15. Microcantilever Displacement Measurement Using a Mechanically Modulated Optical Feedback Interferometer.

    Science.gov (United States)

    Azcona, Francisco J; Jha, Ajit; Yáñez, Carlos; Atashkhooei, Reza; Royo, Santiago

    2016-01-01

    Microcantilever motion detection is a useful tool for the characterization of the physical, chemical and biological properties of materials. In the past, different approaches have been proposed and tested to enhance the behavior, size and simplicity of microcantilever motion detectors. In this paper, a new approach to measure microcantilever motion with nanometric resolution is presented. The proposed approach is based on the concept of mechanically-modulated optical feedback interferometry, a technique that has shown displacement measurement capabilities well within the nanometric scale and that, due to its size, compactness and low cost, may be a suitable choice for measuring nanometric motions in cantilever-like sensors. It will be shown that the sensor, in its current state of development, is capable of following a cantilever sinusoidal trajectory at different sets of frequencies ranging up to 200 Hz and peak to peak amplitudes up to λ / 2 with experimental resolutions in the λ / 100 range. PMID:27367702

  16. Optical particle trapping and dynamic manipulation using spatial light modulation

    DEFF Research Database (Denmark)

    Eriksen, René Lynge

    spots acting as tweezers beams are generated using phase-only spatial light modulation of an incident laser beam together with a generalized phase contrast (GPC) filter. The GPC method acts as a common-path interferometer, which converts encoded phase information into an appropriate intensity pattern...... proven capable of generating a phase pattern from an input amplitude distribution. The birefringent nature of liquid crystals in the SLM is utilized for the generation of an arbitrary two-dimensional state of polarization using two-cascaded SLMs. By means of elliptically polarized light, generated by one...... SLM and a lens-array, angular momentum transfer to multiple birefringent particles is achieved in an optical tweezers system. The rotation direction and angular orientation of the trapped particles are controlled from the SLM device that directly affects the state of polarization. In addition, a novel...

  17. Modulational instability in dispersion-kicked optical fibers

    CERN Document Server

    Nodari, S Rota; Dujardin, G; Kudlinski, A; Mussot, A; Trillo, S; De Bièvre, S

    2015-01-01

    We study, both theoretically and experimentally, modulational instability in optical fibers that have a longitudinal evolution of their dispersion in the form of a Dirac delta comb. By means of Floquet theory, we obtain an exact expression for the position of the gain bands, and we provide simple analytical estimates of the gain and of the bandwidths of those sidebands. An experimental validation of those results has been realized in several microstructured fibers specifically manufactured for that purpose. The dispersion landscape of those fibers is a comb of Gaussian pulses having widths much shorter than the period, which therefore approximate the ideal Dirac comb. Experimental spontaneous MI spectra recorded under quasi continuous wave excitation are in good agreement with the theory and with numerical simulations based on the generalized nonlinear Schr\\"odinger equation.

  18. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development

    Science.gov (United States)

    Gardner, Jonathan (Technical Monitor); Tolls, Volker

    2004-01-01

    The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

  19. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection

    Science.gov (United States)

    Huber, Robert D.; Green, Robert E., Jr.; Vary, Alex; Kautz, Harold

    1990-01-01

    Presented in viewgraph format, the possibility of using laser generation and detection of ultrasound to replace piezoelectric transducers for the acousto-ultrasonic technique is advanced. The advantages and disadvantages of laser acousto-ultrasonics are outlined. Laser acousto-ultrasonics complements standard piezoelectric acousto-ultrasonics and offers non-contact nondestructive evaluation.

  20. Novel Electro-Optical Modulator Utilizing GeO2-Doped Silica Waveguide

    Institute of Scientific and Technical Information of China (English)

    LI Jiusheng; JIA Dagong

    2009-01-01

    In order to achieve a modulator with broad bandwidth and perfect impedance match,a novel electro-optical modulator based on GeO2-doped silica waveguides on silicon substrate is designed.The finite element model of the whole electro-optical modulator is established by means of ANSYS.With the finite element method analysis,the performance of the novel modulator is predicted.The simulation reveals that the designed modulator operates with a product of 3 dB optical bandwidth and modulating length of 226.59 GHz-cm,and a characteristic impedance of 51.6 Ω at 1 550 nm wavelength.Moreover,the calculated electrical reflected power of coplanar waveguide electrode is below -20 dB in the frequency ranging from 45 MHz to 65 GHz.Therefore,the designed modulator has wide modulation bandwidth and perfect impedance match.

  1. Continued analysis of optical frequency-modulated continuous-wave interference.

    Science.gov (United States)

    Zheng, Jesse

    2005-02-10

    I continue to analyze systematically the theory of optical frequency-modulated continuous-wave (FMCW) interference. Two special cases, multiple-beam optical FMCW interference and multiple-wavelength optical FMCW interference, are discussed in detail. Multiple-beam optical FMCW interference generates a signal with multiple frequencies because of mutual interference among the waves. Multiple-wavelength optical FMCW interference produces a signal whose amplitude is modulated by a synthetic wave. The applications of both types of optical FMCW interference are also discussed. PMID:15751857

  2. Material optimization for electro-optic modulation and cascading

    Science.gov (United States)

    Reyes, Jorge; Darracq, Bruno; Canva, Michael; Blanchard-Desce, Mireille H.; Chaput, Frederic; Lahlil, Khalid; Boilot, Jean-Pierre; Brun, Alain; Levy, Yves

    2000-11-01

    A large effort has been devoted to the preparation of organic polymeric materials for electro-optic modulation and more recently for cascading based processes. These materials contain push-pull chromophores either incorporated as guest in a high Tg polymeric matrix (doped polymers) or grafted onto the polymeric matrix. These systems present several advantages but require significant improvement at the molecular level- by designing optimized chromophores with very large molecular figure of merit specific to each application targeted. The sol-gel route was used to prepare hybrid organic-inorganic materials, for the fabrication of amorphous solids of various shapes (bulk, think films...). The results obtained on optimized chromophore-doped poled thin films emphasize that intermolecular interactions have to be taken into account, as already pointed out by Dalton and coworkers. By combining a molecular engineering strategy for getting large molecular figure of merit and by controlling the intermolecular dipole-dipole interactions via both tuning the push-pull chromophore concentration and the incorporation screening carbazole moieties in high concentration. This strategy allows us to obtain a r33 of about 50 pm/V at 831 nm for a new optimized chromophore structure. In parallel, these thin films are being processed to be used as passive components for integrated optics.

  3. Improving the All-Optical Response of SOAs Using a Modulated Holding Signal

    DEFF Research Database (Denmark)

    Bischoff, Svend; Nielsen, Mads Lønstrup; Mørk, Jesper

    2004-01-01

    A method for increasing the all-optical modulation bandwidth of semiconductor optical amplifiers (SOAs) by use of a cross-gain-modulated (XGM) holding signal is suggested and analyzed. The bandwidth improvement is numerically demonstrated by studying wavelength conversion in an SOA-based Mach...

  4. Bandwidth-length trade-off figures of merit for electro-optic traveling wave modulators

    OpenAIRE

    Ibarra Fusté, Jose Antonio; Santos Blanco, M. Concepción

    2013-01-01

    Closed-form expressions explicitly relating modulation bandwidth and active length in electro-optic traveling wave modulators are presented which fully account for skin-effect electrode loss and optical-electrical wave velocities mismatch. Four operative margins have been identified where the bandwidth–length trade-off figure of merit takes simple forms. Peer Reviewed

  5. Optical label switching in telecommunication using semiconductor lasers, amplifiers and electro-absorption modulators

    DEFF Research Database (Denmark)

    Chi, Nan; Christiansen, Lotte Jin; Jeppesen, Palle;

    2004-01-01

    We demonstrate all-optical label encoding and updating for an orthogonally labeled signal in combined IM/FSK modulation format utilizing semiconductor lasers, semiconductor optical amplifiers and electro-absorption modulators. Complete functionality of a network node including two-hop transmissio...

  6. A robust optical phase modulated 60 GHz RoF WDM system

    DEFF Research Database (Denmark)

    Yu, Xianbin; Kozuch, Wojciech; Turkiewicz, Jaroslaw;

    2010-01-01

    robust 4-channel WDM optical phase modulated 60GHz wireless fiber system is proposed and simulated. In this system, a Fabry-Perot (FP) frequency interleaver is designed to suppress optical carriers for 60GHz signal generation. The simulated results show that this phase modulated WDM system...

  7. Sensitivity of a multi-photomultiplier optical module for KM3NeT

    NARCIS (Netherlands)

    Lohner, H.; Mjos, A.

    2009-01-01

    For the KM3NeT neutrino telescope an optical module with a number of small photomultiplier tubes (multi-PMT optical module) will be advantageous for various reasons, e.g. reduced background rate, a larger number of coincidence hits, and sensitivity to ultra-high energy neutrinos. The properties of s

  8. Design-oriented analytic model of phase and frequency modulated optical links

    Science.gov (United States)

    Monsurrò, Pietro; Saitto, Antonio; Tommasino, Pasquale; Trifiletti, Alessandro; Vannucci, Antonello; Cimmino, Rosario F.

    2016-07-01

    An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare performance of the different architectures in terms of linearity and SFDR.

  9. Modulation Depth Based on Frequency-shift Characteristic of LiNbO3 Waveguide Electro-optic Intensity Modulator

    Institute of Scientific and Technical Information of China (English)

    Hui-juan ZHOU; Zhou MENG; Yi LIAO

    2010-01-01

    The modulation depth,defined according to practical mod-ulation results,which changes with the microwave power and its fre-quency,is significant for systems utilizing the frequency-shift charac-teristic of the LiNbO3 waveguide Electro-Optic Intensity Modulator (EOIM).By analyzing the impedance mismatch between the micro-wave source and the EOIM,the effective voltage applied to the RF port of the EOIM is deprived frcm the microwave power and its fre-quency.Associating with analyses of the phase velocity mismatch be-tween the microwave and the optical wave,the theoretical modulation depth has been obtained,which is verified by experimental results.We provide a method to choose the appropriate modulation depth to optimize the desired sideband through proper transmission bias far the system based an the frequency-shift characteristic of the EOIM.

  10. Generation of platicons and frequency combs in optical microresonators with normal GVD by modulated pump

    CERN Document Server

    Lobanov, Valery E; Gorodetsky, Michael L

    2015-01-01

    We demonstrate that flat-topped dissipative solitonic pulses, platicons, and corresponding frequency combs can be excited in optical microresonators with normal group velocity dispersion using either amplitude modulation of the pump or bichromatic pump. Soft excitation may occur in particular frequency range if modulation depth is large enough and modulation frequency is close to the free spectral range of the microresonator.

  11. Large-area Fabry-Perot modulator based on electro-optic polymers

    DEFF Research Database (Denmark)

    Benter, Nils; Bertram, Ralph Peter; Soergel, Elisabeth;

    2006-01-01

    We present a large-area electro-optic Fabry-Perot modulator utilizing a photoaddressable bis-azo polymer placed between two dielectric mirrors with an open aperture of 2 cm. A modulation efficientcy of 1% at an effective modulation voltage of 20 V for a wavelength of 1.55 mymeter is demonstrated...

  12. 8x40 Gb/s RZ all-optical broadcasting utilizing an electroabsorption modulator

    DEFF Research Database (Denmark)

    Xu, Lin; Chi, Nan; Yvind, Kresten;

    2004-01-01

    We experimentally demonstrate all-optical broadcasting through simultaneous 8 × 40 Gb/s wavelength conversion in the RZ format based on cross absorption modulation in an electroabsorption modulator. The original intensity-modulated information is successfully duplicated onto eight wavelengths that...

  13. Frequency Modulation Induced by using the Linear Phase Modulation Method used in a Resonator Micro-optic Gyro

    Institute of Scientific and Technical Information of China (English)

    HONG Ling-Fei; ZHANG Chun-Xi; FENG Li-Shuang; YU Huai-Yong; LEI Ming

    2012-01-01

    Resonator micro-optic gyro (R-MOG) sensing rotation angular-velocity is based on Sagnac effect.We present a frequency modulation (FM) induced by the analog triangle-waveform phase modulation (ATAW-PM) technique in an R-MOG.Compared with the traditional serrodyne phase modulation or digital phase modulation methods,the proposed modulation technique has the intrinsic advantage in free of sweeping-back or step-effect induced pulse noise.The influence on dynamic range and resolution of the R-MOG by the parameters of analog trianglewaveform is theoretically analyzed.Experiments are carried out on an R-MOG composed of an integrated optic resonator with a free spectral range (FSR) and a fitness (F) of 1.6GHz and 61,respectively.Dynamic range of ±500 deg/s and bias drift of 0.6 deg/s over 1 h and 0.05 deg/s for 60 s are reliably obtained.%Resonator micro-optic gyro (R-MOG) sensing rotation angular-velocity is based on Sagnac effect. We present a frequency modulation (FM) induced by the analog triangle-waveform phase modulation (ATAW-PM) technique in an R-MOG. Compared with the traditional serrodyne phase modulation or digital phase modulation methods, the proposed modulation technique has the intrinsic advantage in free of sweeping-back or step-effect induced pulse noise. The influence on dynamic range and resolution of the R-MOG by the parameters of analog triangle-waveform is theoretically analyzed. Experiments are carried out on an R-MOG composed of an integrated optic resonator with a free spectral range (FSR) and a Btness (F) of 1.6 GHz and 61, respectively. Dynamic range of ±500 deg/s and bias drift of 0.6deg/s over 1 h and 0.05deg/s for 60s are reliably obtained.

  14. Measurement of the microwave permittivity of polymer materials for high-speed optical modulator design

    OpenAIRE

    Philippe Auguste, Kenny Robert; Legier, Jean-François; Paleczny, Eric; Halbwax, Mathieu; Mahé, Hind; Fontanieu, Lénaïck; Vilcot, Jean-Pierre

    2010-01-01

    SECTION 6: OPTICAL COMMUNICATIONS (OC) [06.08] International audience We report here a technique that we used to determine the complex permittivity of film structured polymer materials in the microwave frequency range. The goal is to obtain the data that are requested to design the microwave electrodes of Mach-Zehnder type optical modulators. As an example, the technique is applied to two materials that can be used in the fabrication of a high-speed optical polymer based modulator.

  15. A pulse code modulated fiber optic link design for quinault under-water tracking range

    OpenAIRE

    Andersen, David Allen

    1980-01-01

    An underwater fiber optics communication link has been shown to be a realistic alternative to the currently planned coaxial cable link for the shallow-water torpedo tracking range at the Naval Undersea Warfare Engineering Station. The currently planned system is reviewed in this thesis and a fiber optic alternative is discussed. Several possible modulation techniques are studied and compared. Choosing pulse code modulation, a fiber optic link was built and tested using...

  16. Optical label encoding using electroabsorption modulators and investigation of chirp properties

    DEFF Research Database (Denmark)

    Xu, Lin; Chi, Nan; Oxenløwe, Leif Katsuo;

    2003-01-01

    A novel scheme of optical label encoding by wavelength conversion based on electroabsorption modulators (EAMs) is reported. Based on the experimental observations, the chirp properties of the wavelength-converted signal are discussed and a wide dynamic range of the chirp α-parameter is found allo...... allowed. Compared with cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA), the EAM has several advantages, which make it attractive for optical label encoding or other applications as a wavelength converter....

  17. Optimization Design Parameters of Electro-optic Modulators for Low Loss Wide Bandwidth Capability of Optical Communication Systems

    Directory of Open Access Journals (Sweden)

    Ahmed Nabih Zaki Rashed

    2012-06-01

    Full Text Available The effects of temperature, and operating signal wavelength on high frequency radio frequency transmission characteristics are deeply investigated against various materials based electro optic modulator devices such as lithium Niobate (LiNbO3, polymer, and semiconductor materials. On the other hand, we have developed the optimization of the electro optic modulator parameters where the effective index plays an essential role in the evaluation of the bandwidth structure. The effects of design parameters on the modulating voltage and optical bandwidth are also investigated for different materials based electro optic modulators by using rigorous transmission modeling techniques. The low loss wide bandwidth capability of optoelectronic systems makes them attractive for the transmission and processing of microwave signals, while the development of high capacity optical communication systems has required the use of modulation techniques in optical transmitters and receivers. This paper has presented the low loss wide bandwidth for different electrooptic modulators based on design of optimization parameters for high speed transmission performance.

  18. Coherence analysis of optical frequency-modulated continuous-wave interference.

    Science.gov (United States)

    Zheng, Jesse

    2006-06-01

    I analyze the coherence of optical frequency-modulated continuous-wave (FMCW) interference. With a simple model modified from the classical coherence theory, I successfully derive the relationships among the frequency bandwidth, coherence length, and coherence time of the practical optical source, and the contrast of the beat signal in optical FMCW interference. PMID:16724123

  19. SiC Optically Modulated Field-Effect Transistor

    Science.gov (United States)

    Tabib-Azar, Massood

    2009-01-01

    An optically modulated field-effect transistor (OFET) based on a silicon carbide junction field-effect transistor (JFET) is under study as, potentially, a prototype of devices that could be useful for detecting ultraviolet light. The SiC OFET is an experimental device that is one of several devices, including commercial and experimental photodiodes, that were initially evaluated as detectors of ultraviolet light from combustion and that could be incorporated into SiC integrated circuits to be designed to function as combustion sensors. The ultraviolet-detection sensitivity of the photodiodes was found to be less than desired, such that it would be necessary to process their outputs using high-gain amplification circuitry. On the other hand, in principle, the function of the OFET could be characterized as a combination of detection and amplification. In effect, its sensitivity could be considerably greater than that of a photodiode, such that the need for amplification external to the photodetector could be reduced or eliminated. The experimental SiC OFET was made by processes similar to JFET-fabrication processes developed at Glenn Research Center. The gate of the OFET is very long, wide, and thin, relative to the gates of typical prior SiC JFETs. Unlike in prior SiC FETs, the gate is almost completely transparent to near-ultraviolet and visible light. More specifically: The OFET includes a p+ gate layer less than 1/4 m thick, through which photons can be transported efficiently to the p+/p body interface. The gate is relatively long and wide (about 0.5 by 0.5 mm), such that holes generated at the body interface form a depletion layer that modulates the conductivity of the channel between the drain and the source. The exact physical mechanism of modulation of conductivity is a subject of continuing research. It is known that injection of minority charge carriers (in this case, holes) at the interface exerts a strong effect on the channel, resulting in amplification

  20. Highly Linear, Broadband Optical Modulator Based on Electro-optic Polymer

    CERN Document Server

    Zhang, Xingyu; Lin, Che-yun; Wang, Alan X; Hosseini, Amir; Chen, Ray T

    2014-01-01

    In this paper, we present the design, fabrication and characterization of a traveling wave directional coupler modulator based on electro-optic polymer, which is able to provide both high linearity and broad bandwidth. The high linearity is realized by introducing domain-inversion technique in the two-domain directional coupler. A travelling wave electrode is designed to function with bandwidth-length product of 302GHz cm, by achieving low microwave loss, excellent impedance matching and velocity matching, as well as smooth electric field profile transformation. The 3-dB bandwidth of the device is measured to be 10GHz. The spurious free dynamic range of about 110dB Hz^(2/3) is measured over the modulation frequency range 2-8GHz. To the best of our knowledge, such high linearity is first measured at the frequency up to 8GHz. In addition, a 1-to-2 multi-mode interference 3dB-splitter, a photobleached refractive index taper and a quasi-vertical taper are used to reduce the optical insertion loss of the device.

  1. Waveguide electro-optic modulators based on self-assembled material systems

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-fu; MA Jing; SUN De-gui; XU Guo-yang; HO Seng-Tiong; ZHU Pei-wang; KANG Hu; Antonio Facchetti; Tobin J. Marks

    2005-01-01

    Fabrication and characterization of electro-optic modulators based on the novel organic electro-optic materials composed of self-assembled superlattices (SAS) were presented, both wet-dipping self-assembly and vapor phase deposition approaches were discussed. Prototype waveguide electro-optic modulators were fabricated using SAS films integrated with low-loss polymeric materials functioning as partial guiding and cladding layers.Promising electro-optic thin film materials including DTPT and PEPCOOH grown from the vapor phase were used for fabrication and test of electro-optic prototype modulators. Finally,the EO coefficient of tens of pm/V was obtained,which can sufficiently support high-speed and small size EO modulators.

  2. The design of the optical modules of the KM3NeT-Italia project towers

    Science.gov (United States)

    Leonora, Emanuele; Aiello, Sebastiano; Giordano, Valentina

    2016-07-01

    The KM3NeT-Italia project aims to construct a large volume underwater neutrino telescope, to be installed in the depths of the Mediterranean Sea. The R&D and mass production phases of the detection elements of the telescope, the optical modules, were entirely performed in the INFN-LNS site in the harbour of Catania. In November 2014 a first tower of 14 storeys equipped with 84 optical modules was successfully deployed in the Mediterranean Sea site. The design of the optical modules and their main components are described in this paper.

  3. Tunable storage of optical data packets modulated in spectrally efficient formats

    Science.gov (United States)

    Schneider, Thomas

    2013-03-01

    An all-optical telecommunications network requires all-optical routers. These routers would be able to process optical signals directly, without the transformation to the electrical domain. Thus, optical routers have the potential to accelerate telecommunications, i.e. to enhance the data rate and to minimize the latency times. Furthermore, since the double transformation at each network node can be omitted, they could be able to reduce the energy consumption of telecommunications. Key elements of optical routers are optical buffers, which are able to store the optical packets prior to processing in order to avoid congestion. Therefore, many different concepts for the realization of optical buffers have been presented so far. Most of these can just store or delay on-off keyed (OOK) signals. However, in optical telecommunications advanced modulation formats will be increasingly used because they are able to improve the transmission properties and to take advantage of the capacity of optical fibers. Thus, advanced modulation formats can drastically increase the transmissible data rates. Most of these advanced formats modulate the carrier's phase or are a combination of amplitude and phase modulation. Here the storage of amplitude and phase modulated data packets with the so called quasi-light-storage (QLS) method will be shown. The QLS relies on the time-bandwidth coherence of each signal. Thus, as long as the sampling theorem in the frequency domain is not violated, a distortion-free storage of optical data packets with a delay-bandwidth product (DBP) of several thousand bits is possible. Here we will discuss the applicability of the QLS method to advanced modulation formats and we show experimental results of the tunable alloptical storage of OOK modulated signals with a DBP of 160 bit and the storage of phase shift keyed signals with a DBP of 60 bits.

  4. Simultaneous optical carrier and radio frequency re-modulation in radio-over-fiber systems employing reflective SOA modulators

    DEFF Research Database (Denmark)

    Kassar, Carvalho; Calabretta, Nicola; Tafur Monroy, Idelfonso

    2007-01-01

    We demonstrate an innovative full-duplex radio-over-fibre transmission system employing a reflective SOA to perform simultaneous reusing of the optical carrier and data re-modulation, thus avoiding the use of local radiofrequency oscillator at the station sites.......We demonstrate an innovative full-duplex radio-over-fibre transmission system employing a reflective SOA to perform simultaneous reusing of the optical carrier and data re-modulation, thus avoiding the use of local radiofrequency oscillator at the station sites....

  5. Challenges in Polybinary Modulation for Bandwidth Limited Optical Links

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso; Madsen, Peter;

    2016-01-01

    of partial response modulation, employs simple codification and filtering at the transmitter to drastically increase the spectral efficiency. At the receiver side, polybinary modulation requires low complexity direct detection and very little digital signal processing. This paper provides an overview...

  6. Three-dimensional optical storage in fused silica using modulated femtosecond pulses

    Institute of Scientific and Technical Information of China (English)

    Qing Liu(刘青); Guanghua Cheng(程光华); Yishan Wang(王屹山); Zhao Cheng(程昭); Wei Zhao(赵卫); Guofu Chen(陈国夫)

    2004-01-01

    Three-dimensional bitwise optical recording with a density of 500 Gb/cm3 in fused silica using a Ti:sapphire femtosecond laser modulated by binary digits is demonstrated. Laser pulses modulation is realized by modulating two circuits of trigger pulses signal which are used to control laser pulses trapping and switching out from cavity, respectively. Bits are optically readout in both a parallel reading (phase-contrast) and a serial reading (confocal-type) methods. The method for modulating laser pulses can also be used in all of pulsed laser systems which operate in cavity-dumping configuration.

  7. Optimization of coherent optical OFDM transmitter using DP-IQ modulator with nonlinear response

    Science.gov (United States)

    Chang, Sun Hyok; Kang, Hun-Sik; Moon, Sang-Rok; Lee, Joon Ki

    2016-07-01

    In this paper, we investigate the performance of dual polarization orthogonal frequency division multiplexing (DP-OFDM) signal generation when the signal is generated by a DP-IQ optical modulator. The DP-IQ optical modulator is made of four parallel Mach-Zehnder modulators (MZMs) which have nonlinear responses and limited extinction ratios. We analyze the effects of the MZM in the DP-OFDM signal generation by numerical simulation. The operating conditions of the DP-IQ modulator are optimized to have the best performance of the DP-OFDM signal.

  8. Photonic crystal slow light Mach–Zehnder interferometer modulator for optical interconnects

    International Nuclear Information System (INIS)

    Optical interconnects have been considered essential technology which can directly address the problems of electrical interconnects concerning low bandwidth, high latencies and high power consumption. A novel Mach–Zehnder interferometer (MZI) modulator based on a lithium niobate photonic crystal waveguide is proposed. For an optimized design of photonic crystal structure with low group velocity dispersion and low transmission loss, we realize an optimized modulator with a length of only 42.6 µm, a small driver voltage 1.25 V and a high modulation bandwidth up to 100 GHz. The demonstrated MZI modulators can be used as guidance in future all-optical interconnections

  9. A highly efficient thermo-optic microring modulator assisted by graphene

    Science.gov (United States)

    Gan, Sheng; Cheng, Chuantong; Zhan, Yaohui; Huang, Beiju; Gan, Xuetao; Li, Shaojuan; Lin, Shenghuang; Li, Xiaofeng; Zhao, Jianlin; Chen, Hongda; Bao, Qiaoliang

    2015-11-01

    Graphene's remarkable electrical and optical properties afford great potential for constructing various optoelectronic devices, including modulators, photodetectors and pulse lasers. In particular, graphene-based optical modulators were demonstrated to be featured with a broadband response, small footprint, ultrafast speed and CMOS-compatibility, which may provide an alternative architecture for light-modulation in integrated photonic circuits. While on-chip graphene modulators have been studied in various structures, most of them are based on a capacitance-like configuration subjected to complicated fabrication processes and providing a low yield of working devices. Here, we experimentally demonstrate a new type of graphene modulator by employing graphene's electrical and thermal properties, which can be achieved with a simple fabrication flow. On a graphene-coated microring resonator with a small active area of 10 μm2, we have obtained an effective optical modulation via thermal energy electrically generated in a graphene layer. The resonant wavelength of the ring resonator shifts by 2.9 nm under an electrical power of 28 mW, which enables a large modulation depth of 7 dB and a broad operating wavelength range of 6.2 nm with 3 dB modulation. Due to the extremely high electrical and thermal conductivity in graphene, the graphene thermo-optical modulator operates at a very fast switching rate compared with the conventional silicon thermo-optic modulator, i.e. 10%-90% rise (90%-10% fall) time of 750 ns (800 ns). The results promise a novel architecture for massive on-chip modulation of optical interconnects compatible with CMOS technology.

  10. Numerical and experimental analysis of the modulation of fiber Bragg gratings by low-frequency complex acoustic waves

    Science.gov (United States)

    Silva, Ricardo E.; Franco, Marcos A. R.; Neves, Paulo T.; Bartelt, Hartmut; Pohl, Alexandre A. P.

    2016-07-01

    The acoustically modulated bandwidth of fiber Bragg gratings is simulated and experimentally demonstrated. Finite element and transfer matrix methods are used to investigate a superposition of flexural and longitudinal acoustic waves and the induced complex strain in the grating, for the first time. The results show that the longitudinal strain is suitable to generate a bandwidth-voltage response. The modeling is useful for the design and characterization of acousto-optic modulators, which is attractive for the fast control of several photonic devices.

  11. Transverse acousto-electric effect in superconductors

    Science.gov (United States)

    Lipavský, P.; Koláček, J.; Lin, P.-J.

    2016-06-01

    We formulate a theory based on the time-dependent Ginzburg-Landau (TDGL) theory and Newtonian vortex dynamics to study the transverse acousto-electric response of a type-II superconductor with Abrikosov vortex lattice. When exposed to a transverse acoustic wave, Cooper pairs emerge from the moving atomic lattice and moving electrons. As in the Tolman-Stewart effect in a normal metal, an electromagnetic field is radiated from the superconductor. We adapt the equilibrium-based TDGL theory to this non-equilibrium system by using a floating condensation kernel. Due to the interaction between normal and superconducting components, the radiated electric field as a function of magnetic field attains a maximum value occurring below the upper critical magnetic field. This local increase in electric field has weak temperature dependence and is suppressed by the presence of impurities in the superconductor.

  12. Applied photometry, radiometry, and measurements of optical losses

    CERN Document Server

    Bukshtab, Michael

    2012-01-01

    Applied Photometry, Radiometry, and Measurements of Optical Losses reviews and analyzes physical concepts of radiation transfer, providing quantitative foundation for the means of measurements of optical losses, which affect propagation and distribution of light waves in various media and in diverse optical systems and components. The comprehensive analysis of advanced methodologies for low-loss detection is outlined in comparison with the classic photometric and radiometric observations, having a broad range of techniques examined and summarized: from interferometric and calorimetric, resonator and polarization, phase-shift and ring-down decay, wavelength and frequency modulation to pulse separation and resonant, acousto-optic and emissive - subsequently compared to direct and balancing methods for studying free-space and polarization optics, fibers and waveguides. The material is focused on applying optical methods and procedures for evaluation of transparent, reflecting, scattering, absorbing, and aggregat...

  13. Few layers graphene as thermally activated optical modulator in the visible-near IR spectral range.

    Science.gov (United States)

    Benítez, J L; Hernández-Cordero, Juan; Muhl, S; Mendoza, D

    2016-01-01

    We report the temperature modulation of the optical transmittance of a few layers of graphene (FLG). The FLG was heated either by the Joule effect of the current flowing between coplanar electrodes or by the absorption of a continuous-wave 532 nm laser. The optical signals used to evaluate the modulation of the FLG were at 633, 975, and 1550 nm; the last wavelengths are commonly used in optical communications. We also evaluated the effect of the substrate on the modulation effect by comparing the performance of a freely suspended FLG sample with one mounted on a glass substrate. Our results show that the modulation of the optical transmittance of FLG can be from millihertz to kilohertz. PMID:26696185

  14. Integrated High-Speed Digital Optical True-Time-Delay Modules for Synthetic Aperture Radars Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Crystal Research, Inc. proposes an integrated high-speed digital optical true-time-delay module for advanced synthetic aperture radars. The unique feature of this...

  15. 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.

  16. Stokes Space-Based Optical Modulation Format Recognition for Digital Coherent Receivers

    DEFF Research Database (Denmark)

    Borkowski, Robert; Zibar, Darko; Caballero Jambrina, Antonio;

    2013-01-01

    We present a technique for modulation format recognition for heterogeneous reconfigurable optical networks. The method is based on Stokes space signal representation and uses a variational Bayesian expectation maximization machine learning algorithm. Differentiation between diverse common coherent...

  17. Structure Design of Polymer Electro-Optic Modulator with Ultra- Broadband

    Institute of Scientific and Technical Information of China (English)

    Haibo Peng; Boyu Wu; Qiong Song; Fei Lu; Shuyun Luo

    2003-01-01

    Using finite element method, lots of calculating focusing on polymer electro-optic modulators with ultra-broadband were done, a few structures were analyzed. Coplanar waveguide electrode system was advanced, a few real examples was given.

  18. 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.

  19. High Power Electro-Optic Modulator for Space-Based Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ADVR, Inc. proposes the development of a fiber coupled, high power, electro-optically controlled, space qualified, phase modulator for the NASA Laser Interferometer...

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

    International Nuclear Information System (INIS)

    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. Protein-based integrated optical switching and modulation

    Science.gov (United States)

    Ormos, Pál; Fábián, László; Oroszi, László; Wolff, Elmar K.; Ramsden, Jeremy J.; Dér, András

    2002-05-01

    The static and dynamic response of optical waveguides coated with a thin protein film of bacteriorhodopsin was investigated. The size and kinetics of the light-induced refractive index changes of the adlayer were determined under different conditions of illumination. The results demonstrate the applicability of this protein as an active, programmable nonlinear optical material in all-optical integrated circuits.

  2. A continuously tunable modulation scheme for precision control of optical cavities with variable detuning

    CERN Document Server

    Yam, William; Ackley, Sarah; Evans, Matthew; Mavalvala, Nergis

    2015-01-01

    We present a scheme for locking optical cavities with arbitrary detuning many line widths from resonance using an electro-optic modulator that can provide arbitrary ratios of amplitude to phase modulation. We demonstrate our scheme on a Fabry-Perot cavity, and show that a well-behaved linear error signal can be obtained by demodulating the reflected light from a cavity that is detuned by several line widths.

  3. Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel;

    2008-01-01

    We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

  4. Electroabsorption modulators used for all-optical signal processing and labelling

    OpenAIRE

    Xu, Lin; Jeppesen, Palle; Mørk, Jesper

    2004-01-01

    This thesis concerns the applications of semiconductor components, primarily electroabsorption modulators (EAMs), in optical signal processing and labelling for future all optical communication networks. An introduction to electroabsorption modulators is given and several mechanisms that form the basis of electroabsorption are briefly discussed including Franz Keldysh effect, Quantum-Confined Stark Effect (QCSE) and Quantum-Confined Franz-Keldysh effect. QCSE is found to be more effective for...

  5. Analysis and Improvement of Reflection-type Transverse Modulation Optical Voltage Sensors

    Institute of Scientific and Technical Information of China (English)

    LUO Sunan; YE Miaoyuan; XU Yan; CUI Ying

    2001-01-01

    Reflection-type transverse modulation optical voltage sensors, which employ reflection retarders to replace quarter-wave plates, are convenient for practical use. In previous literatures, the measured voltage was all applied to Bi4Ge3O12 crystal along the (110) direction for transverse modulation optical voltage sensor, and crystals are used as sensing materials. In this paper, reflection-type transverse modulation optical voltage sensor has been analyzed theoretically and a novel configuration in which the measured voltage is applied to a Bi4C-e3O12 crystal along the (001) direction with light wave passing through the crystal in the (110) direction has been proposed. According to this theoretical analysis, a novel optical voltage sensor, which can be used in a 220 kV optical fiber voltage transformer, has been designed and assembled. Experimental results showed that the linearity and the stability of the sensor during 24 hours can reach 0.3%.

  6. Integrated optical frequency shifter in silicon-organic hybrid (SOH) technology.

    Science.gov (United States)

    Lauermann, M; Weimann, C; Knopf, A; Heni, W; Palmer, R; Koeber, S; Elder, D L; Bogaerts, W; Leuthold, J; Dalton, L R; Rembe, C; Freude, W; Koos, C

    2016-05-30

    We demonstrate for the first time a waveguide-based frequency shifter on the silicon photonic platform using single-sideband modulation. The device is based on silicon-organic hybrid (SOH) electro-optic modulators, which combine conventional silicon-on-insulator waveguides with highly efficient electro-optic cladding materials. Using small-signal modulation, we demonstrate frequency shifts of up to 10 GHz. We further show large-signal modulation with optimized waveforms, enabling a conversion efficiency of -5.8 dB while suppressing spurious side-modes by more than 23 dB. In contrast to conventional acousto-optic frequency shifters, our devices lend themselves to large-scale integration on silicon substrates, while enabling frequency shifts that are several orders of magnitude larger than those demonstrated with all-silicon serrodyne devices. PMID:27410095

  7. 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.

  8. Electro-Optic Modulator Based on Organic Planar Waveguide Integrated with Prism Coupler

    Science.gov (United States)

    Sarkisov, Sergey S.

    2002-01-01

    The objectives of the project, as they were formulated in the proposal, are the following: (1) Design and development of novel electro-optic modulator using single crystalline film of highly efficient electro-optic organic material integrated with prism coupler; (2) Experimental characterization of the figures-of-merit of the modulator. It is expected to perform with an extinction ratio of 10 dB at a driving signal of 5 V; (3) Conclusions on feasibility of the modulator as an element of data communication systems of future generations. The accomplishments of the project are the following: (1) The design of the electro-optic modulator based on a single crystalline film of organic material NPP has been explored; (2) The evaluation of the figures-of-merit of the electro-optic modulator has been performed; (3) Based on the results of characterization of the figures-of-merit, the conclusion was made that the modulator based on a thin film of NPP is feasible and has a great potential of being used in optic communication with a modulation bandwidth of up to 100 GHz and a driving voltage of the order of 3 to 5 V.

  9. Optical effects module. [housing instruments used to measure degradation of optical samples from contamination during orbital operations

    Science.gov (United States)

    1978-01-01

    The possible degradation of optical samples exposed to the effluent gases and particulate matter emanating from the payload of the space transportation system during orbital operations may be determined by measuring two optical parameters for five samples exposed to this environment, namely transmittance and diffuse reflectance. Any changes detected in these parameters as a function of time during the mission are then attributable to surface contamination or to increased material absorption. These basic functions are attained in the optical effects module by virtue of the following subsystems which are described: module enclosure; light source with collimator and modulator; sample wheel with holders and rotary drive; photomultipliers for radiation detection; processing and sequencing electronic circuitry; and power conditioning interfaces. The functions of these subsystems are reviewed and specified.

  10. Optically tuned terahertz modulator based on annealed multilayer MoS2

    Science.gov (United States)

    Cao, Yapeng; Gan, Sheng; Geng, Zhaoxin; Liu, Jian; Yang, Yuping; Bao, Qiaoling; Chen, Hongda

    2016-03-01

    Controlling the propagation properties of terahertz waves is very important in terahertz technologies applied in high-speed communication. Therefore a new-type optically tuned terahertz modulator based on multilayer-MoS2 and silicon is experimentally demonstrated. The terahertz transmission could be significantly modulated by changing the power of the pumping laser. With an annealing treatment as a p-doping method, MoS2 on silicon demonstrates a triple enhancement of terahertz modulation depth compared with the bare silicon. This MoS2-based device even exhibited much higher modulation efficiency than the graphene-based device. We also analyzed the mechanism of the modulation enhancement originated from annealed MoS2, and found that it is different from that of graphene-based device. The unique optical modulating properties of the device exhibit tremendous promise for applications in terahertz switch.

  11. Modeling of multilayer electrode performance in transverse electro-optic modulators

    Directory of Open Access Journals (Sweden)

    Minmin Zhu

    2011-12-01

    Full Text Available For some electro-optic (EO modulators, lowering the driving voltage is necessary to reduce the power consumption of the modulators. There are four significant factors influencing the driving voltage of the EO modulators: geometrical parameters of wafer and electrodes, surface and embedded electrodes, material properties of wafer, and structure of modulators. Using the superposition method and surface charge technique, the electric fields, halfwave voltages, switching times and optical transmissions of EO modulators with two-layer, three-layer, and four-layer electrodes are calculated, respectively. It is found that the halfwave voltage decreases while the switching time increase slightly as the number of layers increases. Such study demonstrates that using multilayer electrodes is an effective technique of lowering the halfwave voltage, which may have implication of EO modulator design.

  12. The Hands-On Optics Project: a demonstration of module 3-magnificent magnifications

    Science.gov (United States)

    Pompea, Stephen M.; Sparks, Robert T.; Walker, Constance E.

    2014-07-01

    The Hands-On Optics project offers an example of a set of instructional modules that foster active prolonged engagement. Developed by SPIE, OSA, and NOAO through funding from the U.S. National Science Foundation, the modules were originally designed for afterschool settings and museums. However, because they were based on national standards in mathematics, science, and technology, they were easily adapted for use in classrooms. The philosophy and implementation strategies of the six modules will be described as well as lessons learned in training educators. The modules were implementing with the help of optics industry professionals who served as expert volunteers to assist educators. A key element of the modules was that they were developed around an understanding of optics misconceptions and used culminating activities in each module as a form of authentic assessment. Thus student achievement could be measured by evaluating the actual product created by each student in applying key concepts, tools, and applications together at the end of each module. The program used a progression of disciplinary core concepts to build an integrated sequence and crosscutting ideas and practices to infuse the principles of the modern electro-optical field into the modules. Whenever possible, students were encouraged to experiment and to create, and to pursue inquiry-based approaches. The result was a program that had high appeal to regular as well as gifted students.

  13. All-optical wavelength conversion and signal regeneration using an electroabsorption modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    2000-01-01

    All-optical wavelength conversion and signal regeneration based on cross-absorption modulation in an InGaAsP quantum well electroabsorption modulator (EAM) is studied at different bit rates. We present theoretical results showing wavelength conversion efficiency in agreement with existing...

  14. Sol-Gel Material-Enabled Electro-Optic Polymer Modulators.

    Science.gov (United States)

    Himmelhuber, Roland; Norwood, Robert A; Enami, Yasufumi; Peyghambarian, Nasser

    2015-07-27

    Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed.

  15. Silicon electro-optic modulator with high-permittivity gate dielectric layer

    Institute of Scientific and Technical Information of China (English)

    Mengxia Zhu; Zhiping Zhou; Dingshan Gao

    2009-01-01

    A high-permittivity (high-k) material is applied as the gate dielectric layer in a silicon metal-oxidesemiconductor (MOS) capacitor to form a special electro-optic (EO) modulator.Both induced charge density and modulation efficiency in the proposed modulator are improved due to the special structure design and the application of the high-k material.The device has an ultra-compact dimension of 691 μm in length.

  16. Tunable all-optical single-bandpass photonic microwave filter based on spectrally sliced broad optical source and phase modulation.

    Science.gov (United States)

    Chen, Ming; Pan, Wei; Zou, Xihua; Luo, Bin; Yan, Lianshan; Liu, Xinkai

    2013-01-10

    A tunable all-optical single-bandpass photonic microwave filter (PMF) based on spectrally sliced broadband optical source and phase modulation is proposed and experimentally demonstrated. A broadband optical source and a Mach-Zehnder interferometer (MZI) are used to generate continuous optical spectral samples, which are employed to form a finite impulse response filter with a single-bandpass response with the help of a single-mode fiber. A phase modulator is then adopted to eliminate the baseband components in the filtering response. The center frequency of the PMF can be tuned by changing the free spectral range of the MZI. An experiment is performed, and the results demonstrate that the proposed PMF has a single-bandpass without baseband components and a tuning range of 5-15 GHz. PMID:23314649

  17. 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.

  18. Broadband energy-efficient optical modulation by hybrid integration of silicon nanophotonics and organic electro-optic polymer

    CERN Document Server

    Zhang, Xingyu; Subbaraman, Harish; Luo, Jingdong; Jen, Alex K -Y; Chung, Chi-jui; Yan, Hai; Pan, Zeyu; Nelson, Robert L; Chen, Ray T

    2015-01-01

    Silicon-organic hybrid integrated devices have emerging applications ranging from high-speed optical interconnects to photonic electromagnetic-field sensors. Silicon slot photonic crystal waveguides (PCWs) filled with electro-optic (EO) polymers combine the slow-light effect in PCWs with the high polarizability of EO polymers, which promises the realization of high-performance optical modulators. In this paper, a broadband, power-efficient, low-dispersion, and compact optical modulator based on an EO polymer filled silicon slot PCW is presented. A small voltage-length product of V{\\pi}*L=0.282Vmm is achieved, corresponding to an unprecedented record-high effective in-device EO coefficient (r33) of 1230pm/V. Assisted by a backside gate voltage, the modulation response up to 50GHz is observed, with a 3-dB bandwidth of 15GHz, and the estimated energy consumption is 94.4fJ/bit at 10Gbit/s. Furthermore, lattice-shifted PCWs are utilized to enhance the optical bandwidth by a factor of ~10X over other modulators bas...

  19. Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks

    Science.gov (United States)

    Lacava, C.; Liu, Z.; Thomson, D.; Ke, Li; Fedeli, J. M.; Richardson, D. J.; Reed, G. T.; Petropoulos, P.

    2016-02-01

    Communication traffic grows relentlessly in today's networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission.

  20. High-Power, High-Speed Electro-Optic Pockels Cell Modulator

    Science.gov (United States)

    Hawthorne, Justin; Battle, Philip

    2013-01-01

    Electro-optic modulators rely on a change in the index of refraction for the optical wave as a function of an applied voltage. The corresponding change in index acts to delay the wavefront in the waveguide. The goal of this work was to develop a high-speed, high-power waveguide- based modulator (phase and amplitude) and investigate its use as a pulse slicer. The key innovation in this effort is the use of potassium titanyl phosphate (KTP) waveguides, making the highpower, polarization-based waveguide amplitude modulator possible. Furthermore, because it is fabricated in KTP, the waveguide component will withstand high optical power and have a significantly higher RF modulation figure of merit (FOM) relative to lithium niobate. KTP waveguides support high-power TE and TM modes - a necessary requirement for polarization-based modulation as with a Pockels cell. High-power fiber laser development has greatly outpaced fiber-based modulators in terms of its maturity and specifications. The demand for high-performance nonlinear optical (NLO) devices in terms of power handling, efficiency, bandwidth, and useful wavelength range has driven the development of bulk NLO options, which are limited in their bandwidth, as well as waveguide based LN modulators, which are limited by their low optical damage threshold. Today, commercially available lithium niobate (LN) modulators are used for laser formatting; however, because of photorefractive damage that can reduce transmission and increase requirements on bias control, LN modulators cannot be used with powers over several mW, dependent on wavelength. The high-power, high-speed modulators proposed for development under this effort will enable advancements in several exciting fields including lidarbased remote sensing, atomic interferometry, free-space laser communications, and others.

  1. Modulated-splitting-ratio fiber-optic temperature sensor

    Science.gov (United States)

    Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter A.

    1988-01-01

    A fiber-optic temperature sensor is described, which uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

  2. Organic-based electro-optic modulators for microwave photonic applications

    Science.gov (United States)

    Eng, David

    As cutting-edge microwave photonic systems with higher complexity and stringent device requirement are being developed, the demand higher performance modulators with lower drive voltages and higher bandwidth is beginning to overtake the physical limitations of existing modulators based in LiNbO3. To address this growing demand, groundbreaking work in the field of organic electro-optic materials has been achieved over the past 10--15 years that has resulted in materials with electro-optic coefficients up to 10 times that of LiNbO3 and with demonstrated response times into the THz regime. This dissertation details work towards developing low drive-voltage, high bandwidth organic-based electro-optic modulators to support next generation microwave photonic systems. Initial efforts were focused on designing an organic electro-optic material based low frequency phase modulator and developing a fabrication procedure that successfully integrates the material without compromising its electro optic activity. Additionally a procedure for inducing the high electro-optic activity in the waveguide core through a process known as 'poling' was developed. The phase modulators were then characterized to confirm the expected high electro-optic activity and correspondingly low drive voltages. To transition from low frequency modulation to broadband operation it was necessary to gather some dielectric information of the waveguide materials for RF design. Because traditional RF dielectric constant measurements assume thick substrates on the order of 100s of microns, a modified microstrip ring resonator technique was developed to measure the dielectric constant of thin, polymer waveguide films on the order of 10 mum out to 110 GHz. A high frequency traveling wave microstrip modulator was then designed and optimized for operation up to 50 GHz, and efforts were turned towards RF packaging of the microstrip modulators for practical utilization and integration. To feed the RF signals a

  3. A simple model of suppressing stimulated Brillouin scattering in optical fiber with frequency-modulated laser

    International Nuclear Information System (INIS)

    A simple model is developed to study the mechanism of stimulated Brillouin scattering (SBS) suppression with frequency-modulated laser in optical fiber. By taking into account the laser frequency distribution along the fiber induced by frequency modulation, the average effective Brillouin gain is calculated to determine the SBS threshold. Experimental results show agreement with the numerical analysis. The application for SBS suppression in interferometric fiber sensing system is also discussed in this paper. The results show that the maximum input power can be increased effectively by frequency modulation method. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  4. New-generation concentrator modules based on cascade solar cells: Design and optical and thermal properties

    Science.gov (United States)

    Andreev, V. M.; Davidyuk, N. Yu.; Malevski, D. A.; Pan'chak, A. N.; Rumyantsev, V. D.; Sadchikov, N. A.; Chekalin, A. V.; Luque, A.

    2014-11-01

    New-generation concentrator modules use III-V nanoheterostructure cascade solar cells the efficiency of which can be raised to 50% for the number of cascades exceeding three. To obtain a high overall efficiency of photovoltaic conversion in power plants and extend their service time, it is necessary that the design of the modules be optimal in terms of optics and thermal engineering. In this work, main challenges in designing solar modules, such as optical concentration of radiation and residual heat removal, are considered. The results of pilot works that have been recently done in the Ioffe Physical Technical Institute are primarily reported.

  5. Electro-optic modulation in hybrid solgel doped with Disperse Red chromophore

    Science.gov (United States)

    Lu, Dong; Zhang, Hongxi; Fallahi, Mahmoud

    2005-02-01

    An electro-optically active hybrid solgel doped with Disperse Red 13 has been developed by use of a simple solvent-assisted method. It permits a high loading concentration and has low optical loss at 1550 nm. A channel waveguide amplitude modulator has been fabricated by use of active and passive hybrid solgel materials. The device shows an electro-optic coefficient of 14 pm/V at 1550 nm and stable operation.

  6. Optical design of MOEMS-based micro-mechatronic modules for applications in spectroscopy

    Science.gov (United States)

    Tortschanoff, A.; Kremer, M.; Sandner, T.; Kenda, A.

    2014-05-01

    One of the important challenges for widespread application of MOEMS devices is to provide a modular interface for easy handling and accurate driving of the MOEMS elements, in order to enable seamless integration in larger spectroscopic system solutions. In this contribution we present in much detail the optical design of MOEMS driver modules comprising optical position sensing together with driver electronics, which can actively control different electrostatically driven MOEMS. Furthermore we will present concepts for compact spectroscopic devices, based on different MOEMS scanner modules with lD and 2D optical elements.

  7. All-optical OFDM transmitter design using AWGRs and low-bandwidth modulators.

    Science.gov (United States)

    Lowery, Arthur James; Du, Liang

    2011-08-15

    An Arrayed-Waveguide Grating Router (AWGR) can be used as a demultiplexer for an optical OFDM system, as it provides both the serial-to-parallel converter and the optical Fourier transform (FT) in one component. Because an inverse FT is topologically identical to a Fourier transform, the AWGR can also be used as a FT in an OFDM transmitter. In most all-optical OFDM systems the optical modulators are fed with CW tones; however, the subcarriers (SC) will only be perfectly orthogonal if the bandwidth of the data modulators is similar to the total bandwidth of all subcarriers. Using simulations, this paper investigates the reduction in modulator bandwidth that could be achieved if the modulators are placed before an AWGR designed as a FT. This arrangement also allows the complex (IQ) modulators to be replaced with simpler and more-compact phase modulators. We show that these design improvements enable 7.5-GHz bandwidth modulators to be used in a 4 × 10 Gsymbol/s (80 Gbit/s) per polarization per wavelength system. PMID:21934931

  8. All-optical OFDM transmitter design using AWGRs and low-bandwidth modulators

    Science.gov (United States)

    Lowery, Arthur James; Du, Liang

    2011-08-01

    An Arrayed-Waveguide Grating Router (AWGR) can be used as a demultiplexer for an optical OFDM system, as it provides both the serial-to-parallel converter and the optical Fourier transform (FT) in one component. Because an inverse FT is topologically identical to a Fourier transform, the AWGR can also be used as a FT in an OFDM transmitter. In most all-optical OFDM systems the optical modulators are fed with CW tones; however, the subcarriers (SC) will only be perfectly orthogonal if the bandwidth of the data modulators is similar to the total bandwidth of all subcarriers. Using simulations, this paper investigates the reduction in modulator bandwidth that could be achieved if the modulators are placed before an AWGR designed as a FT. This arrangement also allows the complex (IQ) modulators to be replaced with simpler and more-compact phase modulators. We show that these design improvements enable 7.5-GHz bandwidth modulators to be used in a 4 - 10 Gsymbol/s (80 Gbit/s) per polarization per wavelength system.

  9. N over N cascode push pull modulator driver in 130nm CMOS enabling 20Gb/s optical interconnection with Mach-Zehnder modulator

    OpenAIRE

    Liu, Shenghao; Thomson, D.; Li, K.E.; Wilson, Peter; Reed, Graham

    2015-01-01

    The N over N cascode push-pull modulator driver is demonstrated at 20Gbit/s with IBM 130nm technology. Elec-optical measurement of modulator driver integrated with Mach-Zehnder modulator (MZM) is also presented. This modulator driver achieves 50 output impedance matching (for MZM) with on-chip termination. The power consumption of modulator driver is 312 mW and output swing is 3.4V pp on differential.

  10. Electrically tunable metasurface perfect absorbers for ultrathin mid-infrared optical modulators.

    Science.gov (United States)

    Yao, Yu; Shankar, Raji; Kats, Mikhail A; Song, Yi; Kong, Jing; Loncar, Marko; Capasso, Federico

    2014-11-12

    Dynamically reconfigurable metasurfaces open up unprecedented opportunities in applications such as high capacity communications, dynamic beam shaping, hyperspectral imaging, and adaptive optics. The realization of high performance metasurface-based devices remains a great challenge due to very limited tuning ranges and modulation depths. Here we show that a widely tunable metasurface composed of optical antennas on graphene can be incorporated into a subwavelength-thick optical cavity to create an electrically tunable perfect absorber. By switching the absorber in and out of the critical coupling condition via the gate voltage applied on graphene, a modulation depth of up to 100% can be achieved. In particular, we demonstrated ultrathin (thickness < λ0/10) high speed (up to 20 GHz) optical modulators over a broad wavelength range (5-7 μm). The operating wavelength can be scaled from the near-infrared to the terahertz by simply tailoring the metasurface and cavity dimensions. PMID:25310847

  11. Comparison of Modulation Techniques for Underwater Optical Wireless Communication Employing APD Receivers

    Directory of Open Access Journals (Sweden)

    Mazin Ali A. Ali

    2015-06-01

    Full Text Available In this study, we theoretically analyze the performance of an underwater optical wireless communications system using different modulation techniques and an avalanche photodiode APD receiver over underwater environment channels. Based on the LOS geometrical model and combined with signal to noise ratio model for Si and Ge APD and BER; then the impact of the distance of transmission and power of the transmitter and Jerlov water type are analyzed. The characteristics of bit error rate BER for different optical modulation techniques are studied. Simulation results indicate that the performance of H-QAM is more suited for an underwater optical wireless communication. On the other hand, the suitability of avalanche photodiodes under these modulation techniques is discussed, because the photodiode Si APD has more advantages compared with Ge APD when used in an underwater optical communication.

  12. Modulation instability of quasi-plane-wave optical beams in biased photorefractive- photovoltaic crystals

    Institute of Scientific and Technical Information of China (English)

    Lu Ke-Qing; Zhao Wei; Yang Yan-Long; Zhu Xiang-Ping; Li Jin-Ping; Zhang Yan-Peng

    2004-01-01

    We investigate the modulation instability of quasi-plane-wave optical beams in biased photorefractive-photovoltaic crystals by globally treating the space-charge field. The modulation instability growth rate is obtained, which depends on the external bias field, on the bulk photovoltaic effect, and on the ratio of the optical beam's intensity to that of the dark irradiance. Our analysis indicates that this modulation instability growth rate is identical to the modulation instability growth rate studied previously in biased photorefractive-nonphotovoltaic crystals when the bulk photovoltaic effect is negligible for shorted circuits, and predicts the modulation instability growth rate in open- and closed-circuit photorefractive-photovoltaic crystals when the external bias field is absent.

  13. 200Gb/s 10-channel miniature optical interconnect transmitter module for high-performance computing (HPC)

    Science.gov (United States)

    Mohammed, Edris; Au, Hinmeng

    2010-02-01

    A major breakthrough to alleviating the interconnect bottleneck in intra cabinet system in HPC may happen by bringing optics directly to the processor package. In order to do so efficient and compact optical interconnect subassembly modules that utilize simple optical and electrical interfacing schemes are needed. In our current work the development of a novel 10-channel, miniature 7mm(W)x1.8mm(L)x3mm(H), optical interconnect transmitter subassembly module is described. The module consists of a high precision molded optical alignment unit with integrated microlens arrays, highspeed coplanar waveguide (CPW) electrical interfaces and a VCSEL (Vertical Cavity Surface Emitting Laser) array chip which is flip chip mounted. The module is designed to uniquely interface vertically with high-speed electrical I/O lines on a microprocessor style package or a motherboard to convert electrical signals to optical for transmission to other similar units using a standard (Multi-Terminal) MT style optical connector. We report on optical coupling efficiency, misalignment tolerance and high-speed electrical and optical measurements of the module. We have measured 40Gb/s electrical eye for the CPW interfaces on the module and 20Gb/s clear optical eyes for VCSEL assembled module from all the 10 channels to produce an aggregate transmitter bandwidth of 200Gb/s. We also measured 30Gb/s electrical and 20Gb/s optical eyes for the optical subassembly module that is bonded onto a microprocessor style package substrate.

  14. Reconfigurable optical quadrature amplitude modulation converter/encoder using a tunable complex coefficient optical tapped delay line.

    Science.gov (United States)

    Khaleghi, Salman; Chitgarha, Mohammad Reza; Yilmaz, Omer F; Tur, Moshe; Haney, Michael W; Langrock, Carsten; Fejer, Martin M; Willner, Alan E

    2013-05-15

    We experimentally demonstrate a reconfigurable optical converter/encoder for quadrature amplitude modulated (QAM) signals. The system utilizes nonlinear wavelength multicasting, conversion-dispersion delays, and simultaneous nonlinear multiplexing and sampling. We show baud rate tunability (31 and 20 Gbaud) and reconfigurable conversions from lower-order QAM signals to higher-order QAM signals (e.g., 64-QAM). PMID:23938882

  15. A control unit for a laser module of optoelectronic computing environment with dynamic architecture

    Directory of Open Access Journals (Sweden)

    Lipinskii A. Y.

    2013-06-01

    Full Text Available The paper presents the developed control unit of laser modules of optoelectronic acousto-optic computing environment. The unit is based on ARM micro¬con¬troller of Cortex M3 family, and allows alternating between recording (erase and reading modes in accordance with a predetermined algorithm and settings — exposure time and intensity. The principal electric circuit of the presented device, the block diagram of microcontroller algorithm, and the example application of the developed control unit in the layout of the experimental setup are provided.

  16. All-optical modulator based on a ferrofluid core metal cladding waveguide chip

    International Nuclear Information System (INIS)

    We propose a novel optical intensity modulator based on the combination of a symmetrical metal cladding optical waveguide (SMCW) and ferrofluid, where the ferrofluid is sealed in the waveguide to act as a guiding layer. The light matter interaction in the ferrofluid film leads to the formation of a regular nanoparticle pattern, which changes the phase match condition of the ultrahigh order modes in return. When two lasers are incident on the same spot of the waveguide chip, experiments illustrate all-optical modulation of one laser beam by adjusting the intensity of the other laser. A possible theoretical explanation may be due to the optical trapping and Soret effect since the phenomenon is considerable only when the control laser is effectively coupled into the waveguide. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. Optical Intensity Modulation in an LiNbO3 Slab-Coupled Waveguide

    Directory of Open Access Journals (Sweden)

    Yalin Lu

    2008-01-01

    Full Text Available Optical intensity modulation has been demonstrated through switching the optical beam between the main core waveguide and a closely attached leaky slab waveguide by applying a low-voltage electrical field. Theory for simulating such an LiNbO3 slab-coupled waveguide structure was suggested, and the result indicates the possibility of making the spatial guiding mode large, circular and symmetric, which further allows the potential to significantly reduce the coupling losses with adjacent lasers and optical networks. Optical intensity modulation using electro-optic effect was experimentally demonstrated in a 5 cm long waveguide fabricated by using a procedure of soft proton exchange and then an overgrowth of thin LN film on top of a c-cut LiNbO3 wafer.

  18. A direct modulated optical link for MRI RF receive coil interconnection

    Science.gov (United States)

    Yuan, Jing; Wei, Juan; Shen, G. X.

    2007-11-01

    Optical glass fiber is a promising alternative to traditional coaxial cables for MRI RF receive coil interconnection to avoid any crosstalk and electromagnetic interference between multiple channels. A direct modulated optical link is proposed for MRI coil interconnection in this paper. The link performances of power gain, frequency response and dynamic range are measured. Phantom and in vivo human head images have been demonstrated by the connection of this direct modulated optical link to a head coil on a 0.3 T MRI scanner for the first time. Comparable image qualities to coaxial cable link verify the feasibility of using the optical link for imaging with minor modification on the existing scanners. This optical link could also be easily extended for multi-channel array interconnections at high field of 1.5 T.

  19. Self-referencing a continuous-wave laser with electro-optic modulation

    CERN Document Server

    Beha, Katja; Del'Haye, Pascal; Coillet, Aurélien; Diddams, Scott A; Papp, Scott B

    2015-01-01

    We phase-coherently measure the frequency of continuous-wave (CW) laser light by use of optical-phase modulation and f-2f nonlinear interferometry. Periodic electro-optic modulation (EOM) transforms the CW laser into a continuous train of picosecond optical pulses. Subsequent nonlinear-fiber broadening of this EOM frequency comb produces a supercontinuum with 160 THz of bandwidth. A critical intermediate step is optical filtering of the EOM comb to reduce electronic-noise-induced decoherence of the supercontinuum. Applying f-2f self-referencing with the supercontinuum yields the carrier-envelope offset frequency of the EOM comb, which is precisely the difference of the CW laser frequency and an exact integer multiple of the EOM pulse repetition rate. Here we demonstrate absolute optical frequency metrology and synthesis applications of the self-referenced CW laser with <5E-14 fractional accuracy and stability.

  20. Study on electroabsorption modulators and grating couplers for optical interconnects

    OpenAIRE

    Tang, Yongbo

    2010-01-01

    Decades of efforts have pushed the replacement of electrical interconnects by optical links to the interconnects between computers, racks and circuit boards. It may be expected that optical solutions will further be used for inter-chip and intra-chip interconnects with potential benefits in bandwidth, capacity, delay, power consumption and crosstalk. Silicon integration is emerging to be the best candidate nowadays due to not only the dominant status of silicon in microelectronics but also th...

  1. Reconstruction of Optical Thickness from Hoffman Modulation Contrast Images

    DEFF Research Database (Denmark)

    Olsen, Niels Holm; Sporring, Jon; Nielsen, Mads;

    2003-01-01

    Hoffman microscopy imaging systems are part of numerous fertility clinics world-wide. We discuss the physics of the Hoffman imaging system from optical thickness to image intensity, implement a simple, yet fast, reconstruction algorithm using Fast Fourier Transformation and discuss the usability...... of the method on a number of cells from a human embryo. Novelty is identifying the non-linearity of a typical Hoffman imaging system, and the application of Fourier Transformation to reconstruct the optical thickness....

  2. Techniques for Effective Optical Noise Rejection in Amplitude-Modulated Laser Optical Radars for Underwater Three-Dimensional Imaging

    Directory of Open Access Journals (Sweden)

    R. Ricci

    2010-01-01

    Full Text Available Amplitude-modulated (AM laser imaging is a promising technology for the production of accurate three-dimensional (3D images of submerged scenes. The main challenge is that radiation scattered off water gives rise to a disturbing signal (optical noise that degrades more and more the quality of 3D images for increasing turbidity. In this paper, we summarize a series of theoretical findings, that provide valuable hints for the development of experimental methods enabling a partial rejection of optical noise in underwater imaging systems. In order to assess the effectiveness of these methods, which range from modulation/demodulation to polarimetry, we carried out a series of experiments by using the laboratory prototype of an AM 3D imager (λ = 405 nm for marine archaeology surveys, in course of realization at the ENEA Artificial Vision Laboratory (Frascati, Rome. The obtained results confirm the validity of the proposed methods for optical noise rejection.

  3. Techniques for Effective Optical Noise Rejection in Amplitude-Modulated Laser Optical Radars for Underwater Three-Dimensional Imaging

    Directory of Open Access Journals (Sweden)

    Francucci M

    2010-01-01

    Full Text Available Amplitude-modulated (AM laser imaging is a promising technology for the production of accurate three-dimensional (3D images of submerged scenes. The main challenge is that radiation scattered off water gives rise to a disturbing signal (optical noise that degrades more and more the quality of 3D images for increasing turbidity. In this paper, we summarize a series of theoretical findings, that provide valuable hints for the development of experimental methods enabling a partial rejection of optical noise in underwater imaging systems. In order to assess the effectiveness of these methods, which range from modulation/demodulation to polarimetry, we carried out a series of experiments by using the laboratory prototype of an AM 3D imager ( = 405 nm for marine archaeology surveys, in course of realization at the ENEA Artificial Vision Laboratory (Frascati, Rome. The obtained results confirm the validity of the proposed methods for optical noise rejection.

  4. Invited Article: Polarization diversity and modulation for high-speed optical communications: architectures and capacity

    Science.gov (United States)

    Shieh, William; Khodakarami, Hamid; Che, Di

    2016-07-01

    Polarization is one of the fundamental properties of optical waves. To cope with the exponential growth of the Internet traffic, optical communications has advanced by leaps and bounds within the last decade. For the first time, the polarization domain has been extensively explored for high-speed optical communications. In this paper, we discuss the general principle of polarization modulation in both Jones and Stokes spaces. We show that there is no linear optical device capable of transforming an arbitrary input polarization into one that is orthogonal to itself. This excludes the receiver self-polarization diversity architecture by splitting the signal into two branches, and then transferring one of the branches into orthogonal polarization. We next propose a novel Stokes vector (SV) detection architecture using four single-ended photodiodes (PD) that can recover a full set of SV. We then derive a closed-form expression for the information capacity of different SV detection architectures and compare the capacity of our proposed architectures with that of intensity-modulated directly-detected (IM/DD) method. We next study the 3-PD SV detection architecture where a subset of SV is detected, and devise a novel modulation algorithm that can achieve 2-dimensional modulation with the 3-PD detection. By using cost-effective SV receivers, polarization modulation and multiplexing offers a powerful solution for short-reach optical networks where the wavelength domain is quickly exhausted.

  5. Atomic-layer molybdenum sulfide optical modulator for visible coherent light.

    Science.gov (United States)

    Zhang, Yuxia; Wang, Shuxian; Yu, Haohai; Zhang, Huaijin; Chen, Yanxue; Mei, Liangmo; Di Lieto, Alberto; Tonelli, Mauro; Wang, Jiyang

    2015-01-01

    Coherent light sources in the visible range are playing important roles in our daily life and modern technology, since about 50% of the capability of the our human brains is devoted to processing visual information. Visible lasers can be achieved by nonlinear optical process of infrared lasers and direct lasing of gain materials, and the latter has advantages in the aspects of compactness, efficiency, simplicity, etc. However, due to lack of visible optical modulators, the directly generated visible lasers with only a gain material are constrained in continuous-wave operation. Here, we demonstrated the fabrication of a visible optical modulator and pulsed visible lasers based on atomic-layer molybdenum sulfide (MoS2), a ultrathin two-dimensional material with about 9-10 layers. By employing the nonlinear absorption of the modulator, the pulsed orange, red and deep red lasers were directly generated. Besides, the present atomic-layer MoS2 optical modulator has broadband modulating properties and advantages in the simple preparation process. The present results experimentally verify the theoretical prediction for the low-dimensional optoelectronic modulating devices in the visible wavelength region and may open an attractive avenue for removing a stumbling block for the further development of pulsed visible lasers. PMID:26067821

  6. Graphene electro-optic modulator with 30 GHz bandwidth

    Science.gov (United States)

    Phare, Christopher T.; Daniel Lee, Yoon-Ho; Cardenas, Jaime; Lipson, Michal

    2015-08-01

    Graphene has generated exceptional interest as an optoelectronic material because its high carrier mobility and broadband absorption promise to make extremely fast and broadband electro-optic devices possible. Electro-optic graphene modulators previously reported, however, have been limited in bandwidth to a few gigahertz because of the large capacitance required to achieve reasonable voltage swings. Here, we demonstrate a graphene electro-optic modulator based on resonator loss modulation at critical coupling that shows drastically increased speed and efficiency. Our device operates with a 30 GHz bandwidth and with a state-of-the-art modulation efficiency of 15 dB per 10 V. We also show the first high-speed large-signal operation in a graphene modulator, paving the way for fast digital communications using this platform. The modulator uniquely uses silicon nitride waveguides, an otherwise completely passive material platform, with promising applications for ultra-low-loss broadband structures and nonlinear optics.

  7. James Webb Space Telescope Optical Telescope Element/Integrated Science Instrument Module (OTIS) Status

    Science.gov (United States)

    Feinberg, Lee; Voyton, Mark; Lander, Juli; Keski-Kuha, Ritva; Matthews, Gary

    2016-01-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirror center of curvature optical tests, electrical and operational tests, acoustics and vibration testing at the Goddard Space Flight Center before being shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparation for the cryogenic optical testing, the JWST project has built a Pathfinder telescope and has completed two Optical Ground System Equipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize optical test results to date and status the final Pathfinder test and the OTIS integration and environmental test preparations

  8. A recirculating delayed self-heterodyne method using a Mach-Zehnder modulator for kHz-linewidth measurement

    Science.gov (United States)

    Deng, Shuo; Li, Min; Gao, Hongyun; Dai, Yawen

    2016-09-01

    A laser linewidth measurement method which uses a Mach-Zehnder electro-optic modulator (MZM) is proposed in a loss-compensated recirculating delayed self-heterodyne interferometer (LC-RDSHI). Compared with the traditional acousto-optic modulator (AOM), the electro-optic modulator has the merits of broader bandwidth, lower insertion loss, higher extinction ratio and thus, a wider application. A theoretical analysis shows that the power spectrum curve of the novel measurement system is a Lorentzian line, which fits well with experiment. The linewidth is measured to be 137 ± 7 kHz at a frequency shift of 4 GHz. Measurement of a distributed feedback Bragg (DFB) laser has manifested that the linewidth broadens from 98.5 kHz to 137.4 kHz as the operating temperature changes by 16 °C. This work will allow investigation of narrow linewidth semiconductor and fiber laser stability.

  9. Dynamic photophoresis-based optical trapping using a spatial light modulator

    Science.gov (United States)

    Porfirev, Aleksey P.; Skidanov, Roman V.

    2016-04-01

    We investigate optical trapping light-absorbing particles in the air employing photophoretic forces with optical tweezers generated by a spatial light modulator (SLM). SLM gives us the opportunity to form optical tweezers for multiple trapping in several planes. We investigate the possibility of using lenses with various focal lengths for trapping light-absorbing microparticles with the SLM. We used lenses with a large focal length and a large depth of focus. The results shown in this paper could be useful in various applications of optics and biology.

  10. Integration of Optical Manipulation and Electrophysiological Tools to Modulate and Record Activity in Neural Networks

    Science.gov (United States)

    Difato, F.; Schibalsky, L.; Benfenati, F.; Blau, A.

    2011-07-01

    We present an optical system that combines IR (1064 nm) holographic optical tweezers with a sub-nanosecond-pulsed UV (355 nm) laser microdissector for the optical manipulation of single neurons and entire networks both on transparent and non-transparent substrates in vitro. The phase-modulated laser beam can illuminate the sample concurrently or independently from above or below assuring compatibility with different types of microelectrode array and patch-clamp electrophysiology. By combining electrophysiological and optical tools, neural activity in response to localized stimuli or injury can be studied and quantified at sub-cellular, cellular, and network level.

  11. Magneto-optic transmittance modulation observed in a hybrid graphene–split ring resonator terahertz metasurface

    Energy Technology Data Exchange (ETDEWEB)

    Zanotto, Simone; Pitanti, Alessandro [NEST, Istituto Nanoscienze–CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa (Italy); Lange, Christoph; Maag, Thomas; Huber, Rupert [Department of Physics, University of Regensburg, 93040 Regensburg (Germany); Miseikis, Vaidotas; Coletti, Camilla [CNI@NEST, Istituto Italiano di Tecnologia, P.za S. Silvestro 12, 56127 Pisa (Italy); Degl' Innocenti, Riccardo [Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Baldacci, Lorenzo [Scuola Superiore Sant' Anna, Institute of Life Sciences, P.za Martiri della Libertà 33, 56127 Pisa (Italy); Tredicucci, Alessandro [NEST, Istituto Nanoscienze-CNR and Dipartimento di Fisica “E. Fermi,” Università di Pisa, L.go Pontecorvo 3, 56127 Pisa (Italy)

    2015-09-21

    By placing a material in close vicinity of a resonant optical element, its intrinsic optical response can be tuned, possibly to a wide extent. Here, we show that a graphene monolayer, spaced a few tenths of nanometers from a split ring resonator metasurface, exhibits a magneto-optical response which is strongly influenced by the presence of the metasurface itself. This hybrid system holds promises in view of thin optical modulators, polarization rotators, and nonreciprocal devices, in the technologically relevant terahertz spectral range. Moreover, it could be chosen as the playground for investigating the cavity electrodynamics of Dirac fermions in the quantum regime.

  12. Radio over fiber transceiver employing phase modulation of an optical broadband source.

    Science.gov (United States)

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

    2010-10-11

    This paper proposes a low-cost RoF transceiver for multichannel SCM/WDM signal distribution suitable for future broadband access networks. The transceiver is based on the phase modulation of an optical broadband source centered at third transmission window. Prior to phase modulation the optical broadband source output signal is launched into a Mach-Zehnder interferometer structure, as key device enabling radio signals propagation over the optical link. Furthermore, an optical CWDM is employed to create a multichannel scenario by performing the spectral slicing of the modulated optical signal into a number of channels each one conveying the information from the central office to different base stations. The operation range is up to 20 GHz with a modulation bandwidth around of 500 MHz. Experimental results of the transmission of SCM QPSK and 64-QAM data through 20 Km of SMF exhibit good EVM results in the operative range determined by the phase-to-intensity conversion process. The proposed approach shows a great suitability for WDM networks based on RoF signal transport and also represents a cost-effective solution for passive optical networks. PMID:20941075

  13. Alignment and integration of thin, lightweight x-ray optics into modules

    Science.gov (United States)

    Biskach, Michael P.; Chan, Kai-Wing; Mazzarella, James R.; McClelland, Ryan S.; Saha, Timo T.; Schofield, Mark J.; Zhang, William W.

    2014-07-01

    Future X-ray telescopes with high angular resolution and high throughput optics will help enable new high energy observations. X-ray optics in development at NASA Goddard Space Flight Center by the Next Generation X-ray Optics (NGXO) group utilizes a Flight Mirror Assembly (FMA) comprised of dozens of mirror modules populated with mirror segments aligned to a common focus. Mirror segments are currently aligned and permanently fixed into a module one at a time with emphasis on preventing degradation of the overall module performance. To meet cost and schedule requirements, parallelization and automation of the module integration process must be implemented. Identification of critical mirror segment alignment factors in addition to the progress towards a robust and automated module integration process is presented. There is a fundamental need for a reliable mirror segment alignment and bonding process that will be performed on hundreds or thousands of mirror segments. Results from module X-ray performance verification tests are presented to confirm module performance meets requirements.

  14. Impact of modulator chirp in 100 Gbps class optical discrete multi-tone transmission system

    Science.gov (United States)

    Nishihara, Masato; Tanaka, Toshiki; Takahara, Tomoo; Li, Lei; Tao, Zhenning; Rasmussen, Jens C.

    2012-12-01

    Discrete multi-tone (DMT) technology is an attractive modulation technique for short reach optical transmission system. One of the main factors that limit the performance of the 1.5-μm band DMT system is the interplay between the chromatic dispersion of the transmission fiber and the chirp characteristic of the transmitter. We experimentally measured and compared the chirp characteristics of various modulator configurations, which are lithium-niobate Mach-Zehnder modulator, directly modulated laser, and electro-absorption modulator, by the frequency discriminator method using MZ interferometer. We also measured and compared the transmission characteristics of the transmitters using above-mentioned modulators and discuss the suitable transmitter configuration for DMT technology.

  15. Electrically modulated transparent liquid crystal-optical grating projection

    DEFF Research Database (Denmark)

    Buss, Thomas; Smith, Cameron; Kristensen, Anders

    2013-01-01

    A transparent, fully integrated electrically modulated projection technique is presented based on light guiding through a thin liquid crystal layer covering sub-wavelength gratings. The reported device operates at 10 V with response times of 4.5 ms. Analysis of the liquid crystal alignment shows...

  16. Two-tone intensity-modulated optical stimulus for self-referencing microwave characterization of high-speed photodetectors

    Science.gov (United States)

    Wang, Heng; Zhang, Shangjian; Zou, Xinhai; Zhang, Yali; Lu, Rongguo; Zhang, Zhiyao; Zhang, Xiaoxia; Liu, Yong

    2016-08-01

    The two-tone intensity modulated optical stimulus is proposed and demonstrated for measuring the high-frequency response of photodetectors. The method provides a narrow linewidth and wide bandwidth optical stimulus based on the two-tone modulation of a Mach-Zehnder electro-optical intensity modulator, and achieves the self-referenced measurement of photodetectors without the need for correcting the power variation of optical stimulus. Moreover, the two-tone intensity modulation method allows bias-independent measurement with doubled measuring frequency range. In the experiment, the consistency between our method and the conventional methods verifies the simple but accurate measurement.

  17. Potential roles of optical interconnections within broadband switching modules

    Science.gov (United States)

    Lalk, Gail R.; Habiby, Sarry F.; Hartman, Davis H.; Krchnavek, Robert R.; Wilson, Donald K.; Young, Kenneth C., Jr.

    1991-04-01

    An investigation of potential physical design bottlenecks in future broadband telecommunication switches has led to the identification of several areas where optical interconnections may play a role in the practical realization of required system performance. In the model used the speed and interconnection densities as well as requirements for ease-of-access and efficient power utilization challenge conventional partitioning and packaging strategies. Potential areas where optical interconnections may relieve some of the physical design bottlenecks include fiber management at the customer interface to the switch routing and distribution of high-density interconnections within the fabric of the switch and backplane interconnections to increase system throughput.

  18. Velocity matching of a GaAs electro-optic modulator.

    Science.gov (United States)

    Haxha, Shyqyri; Rahman, B M Azizur; Obayya, Salah S A; Grattan, Kenneth T V

    2003-12-20

    New designs for the velocity matching of a deep-etched semiconductor electro-optic modulator are presented. A tantalum pentoxide (Ta2O5) coating is considered here for achieving velocity matching between the microwave and the optical signals. The effects of the velocity mismatch, the conductor loss, the dielectric loss, and the impedance mismatch are studied in relation to the optical bandwidth of a high-speed semiconductor modulator. It is shown that both the dielectric loss and the impedance matching play key roles for velocity-matched high-speed modulators with low conductor loss. The effects of Ta2O5 thickness on the overall bandwidth and on the half-wave voltage-length product VpiL are also reported. PMID:14717296

  19. Optimised dispersion management and modulation formats for high speed optical communication systems

    DEFF Research Database (Denmark)

    Tokle, Torger

    2004-01-01

    This thesis studies dispersion management and modulation formats for optical communication systems using per channel bit rates at and above 10 Gbit/s. Novel modulation formats—including recently proposed multilevel phase modulation—are investigated and demonstrated at bit rates up to 80 Gbit/s. New...... both narrow spectral width and good transmission properties. The cost of an optical communication system can be lowered by using longer span lengths to reduce the number of amplifier stations. We experimentally study optimum dispersion compensation schemes for systems with 160 km fibre spans made...... system performance. Differential phase shift keying (DPSK) has recently been showed to be a promising modulation format for optical communication. We study DPSK with focus on differential quadrature phase shift keying (DQPSK). In a 12.5 Gbit/s WDM system, we demonstrate the suitability of DQPSK for ultra...

  20. An Optical Labeling Scheme with Novel DPSK/PPM Orthogonal Modulation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Rui; XIN Xiang-Jun; WANG Yong-Jun; ZHANG Zi-Xing; YU Chong-Xiu

    2010-01-01

    @@ A novel differential-phase-shift-keying (DPSK)/pulse-position-modulation (PPM) orthogonal modulation is proposed for optical labeling applications,with PPM data as the high-speed payload and DPSK signal as the optical label.The systematic setup for the proposed scheme and research on bit-error rate is presented.The results show that at the bit-error rate of 10-9,the power penalties for 70km fiber transmission are in the range of 1-3dB to DPSK label and 5-6dB to PPM payload in our simulation system.This is under the condition that the large extinction ratio of 18-19 dB is used for the intensity modulators of the PPM payload,with a well received DPSK label.Thus the feasibility of the proposed scheme for all optical transmission networks is clearly verified.

  1. Noise Spectrum of a Semiconductor Optical Amplifier Excited by a Modulated Signal

    DEFF Research Database (Denmark)

    Blaaberg, Søren; Mørk, Jesper

    2014-01-01

    A detailed analysis of the noise spectrum of a semiconductor optical amplifier excited by an amplitude-modulated input signal is presented. This extends the well-established theory for the case of continuous-wave input signals and is relevant for various applications within optical signal...... processing. One important example is the analysis of noise in microwave photonic elements based on slow-light propagation in semiconductor optical amplifiers. Expressions for the noise spectra are derived and the dependence on important operation parameters, such as input power, modulation depth......, and modulation frequency, is investigated and explained. We find several interesting modifications to the spectra compared with the continuous-wave case. In particular, the side-bands present in the input-signal lead via four-wave mixing effects to additional structure in the spectra as well as additional noise...

  2. A novel optical labeling scheme using a FSK modulated DFB laser integrated with an EA modulator

    DEFF Research Database (Denmark)

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

    2003-01-01

    The feasibility of an optical FSK labeling scheme is demonstrated. An optical signal consisting of a 10 Gb/s payload and a 312 Mb/s label was generated, and its performance was evaluated in an 88 km transmission link....

  3. Short optical pulse generation at 40 GHz with a bulk electro-absorption modulator packaged device

    Science.gov (United States)

    Langlois, Patrick; Moore, Ronald; Prosyk, Kelvin; O'Keefe, Sean; Oosterom, Jill A.; Betty, Ian; Foster, Robert; Greenspan, Jonathan; Singh, Priti

    2003-12-01

    Short optical pulse generation at 40GHz and 1540nm wavelength is achieved using fully packaged bulk quaternary electro-absorption modulator modules. Experimental results obtained with broadband and narrowband optimized packaged modules are presented and compared against empirical model predictions. Pulse duty cycle, extinction ratio and chirp are studied as a function of sinusoidal drive voltage and detuning between operating wavelength and modulator absorption band edge. Design rules and performance trade-offs are discussed. Low-chirp pulses with a FWHM of ~12ps and sub-4ps at a rate of 40GHz are demonstrated. Optical time-domain demultiplexing of a 40GHz to a 10GHz pulse train is also demonstrated with better than 20dB extinction ratio.

  4. Cylindrical PVF2 film based fiber optic phase modulator - Phase shift nonlinearity and frequency response

    Science.gov (United States)

    Sudarshanam, V. S.; Claus, Richard O.

    1993-03-01

    A new cylindrical coil configuration for polyvinylidene flouride (PVF2) film based fiber optic phase modulator is studied for the frequency response and nonlinearity of phase shift at the resonance frequency. This configuration, hitherto unapproached for PVF2 film modulators, offers resonance at well defined, controllable and higher frequencies than possible for the flat-strip configuration. Two versions of this configuration are presented that differ strongly in both the resonance frequency and the phase shift nonlinearity coefficient.

  5. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  6. All-optical wavelength conversion and signal regeneration using an electroabsorption modulator

    OpenAIRE

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    2000-01-01

    All-optical wavelength conversion and signal regeneration based on cross-absorption modulation in an InGaAsP quantum well electroabsorption modulator (EAM) is studied at different bit rates. We present theoretical results showing wavelength conversion efficiency in agreement with existing experimental results, and the signal regeneration capability of the device is investigated. In particular, we demonstrate the dependence of the extinction ratio of both the converted signal and the control s...

  7. Modulation instability of broad optical beams in nonlinear media with general nonlinearity

    Institute of Scientific and Technical Information of China (English)

    Hongcheng Wang; Weilong She

    2006-01-01

    @@ The modulation instability of quasi-plane-wave optical beams is investigated in the frame of generalized Schr(o)dinger equation with the nonlinear term of a general form. General expressions are derived for the dispersion relation, the critical transverse spatial frequency, as well as the instability growth rate.The analysis generalizes the known results reported previously. A detailed discussion on the modulation instability in biased centrosymmetric photorefractive media is also given.

  8. Experimental demonstration of large capacity WSDM optical access network with multicore fibers and advanced modulation formats.

    Science.gov (United States)

    Li, Borui; Feng, Zhenhua; Tang, Ming; Xu, Zhilin; Fu, Songnian; Wu, Qiong; Deng, Lei; Tong, Weijun; Liu, Shuang; Shum, Perry Ping

    2015-05-01

    Towards the next generation optical access network supporting large capacity data transmission to enormous number of users covering a wider area, we proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers with advanced modulation formats. As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers with 58.7km distance. As a cost-effective modulation scheme for access network, the optical OFDM-QPSK signal has been intensity modulated on the downstream transmission in the optical line terminal (OLT) and it was directly detected in the optical network unit (ONU) after MCF transmission. 10 wavelengths with 25GHz channel spacing from an optical comb generator are employed and each wavelength is loaded with 5Gb/s OFDM-QPSK signal. After amplification, power splitting, and fan-in multiplexer, 10-wavelength downstream signal was injected into six outer layer cores simultaneously and the aggregation downstream capacity reaches 300 Gb/s. -16 dBm sensitivity has been achieved for 3.8 × 10-3 bit error ratio (BER) with 7% Forward Error Correction (FEC) limit for all wavelengths in every core. Upstream signal from ONU side has also been generated and the bidirectional transmission in the same core causes negligible performance degradation to the downstream signal. As a universal platform for wired/wireless data access, our proposed architecture provides additional dimension for high speed mobile signal transmission and we hence demonstrated an upstream delivery of 20Gb/s per wavelength with QPSK modulation formats using the inner core of MCF emulating a mobile backhaul service. The IQ modulated data was coherently detected in the OLT side. -19 dBm sensitivity has been achieved under the FEC limit and more than 18 dB power budget is guaranteed.

  9. Experimental demonstration of large capacity WSDM optical access network with multicore fibers and advanced modulation formats.

    Science.gov (United States)

    Li, Borui; Feng, Zhenhua; Tang, Ming; Xu, Zhilin; Fu, Songnian; Wu, Qiong; Deng, Lei; Tong, Weijun; Liu, Shuang; Shum, Perry Ping

    2015-05-01

    Towards the next generation optical access network supporting large capacity data transmission to enormous number of users covering a wider area, we proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers with advanced modulation formats. As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers with 58.7km distance. As a cost-effective modulation scheme for access network, the optical OFDM-QPSK signal has been intensity modulated on the downstream transmission in the optical line terminal (OLT) and it was directly detected in the optical network unit (ONU) after MCF transmission. 10 wavelengths with 25GHz channel spacing from an optical comb generator are employed and each wavelength is loaded with 5Gb/s OFDM-QPSK signal. After amplification, power splitting, and fan-in multiplexer, 10-wavelength downstream signal was injected into six outer layer cores simultaneously and the aggregation downstream capacity reaches 300 Gb/s. -16 dBm sensitivity has been achieved for 3.8 × 10-3 bit error ratio (BER) with 7% Forward Error Correction (FEC) limit for all wavelengths in every core. Upstream signal from ONU side has also been generated and the bidirectional transmission in the same core causes negligible performance degradation to the downstream signal. As a universal platform for wired/wireless data access, our proposed architecture provides additional dimension for high speed mobile signal transmission and we hence demonstrated an upstream delivery of 20Gb/s per wavelength with QPSK modulation formats using the inner core of MCF emulating a mobile backhaul service. The IQ modulated data was coherently detected in the OLT side. -19 dBm sensitivity has been achieved under the FEC limit and more than 18 dB power budget is guaranteed. PMID:25969194

  10. Exact control of parity-time symmetry in periodically modulated nonlinear optical couplers

    CERN Document Server

    Yang, Baiyuan; Hu, QiangLin; Yu, XiaoGuang

    2016-01-01

    We propose a mechanism for realization of exact control of parity-time (PT) symmetry by using a periodically modulated nonlinear optical coupler with balanced gain and loss. It is shown that for certain appropriately chosen values of the modulation parameters, we can construct a family of exact analytical solutions for the two-mode equations describing the dynamics of such nonlinear couplers. These exact solutions give explicit examples that allow us to precisely manipulate the system from nonlinearity-induced symmetry breaking to PT symmetry, thus providing an analytical approach to the all-optical signal control in nonlinear PT-symmetric structures.

  11. Performance characterization of an internsity-modulated fiber optic displacement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Erik Allan [Los Alamos National Laboratory; Todd, Michael D [Los Alamos National Laboratory; Puckett, Santhony D [Los Alamos National Laboratory

    2010-09-30

    A testbed simulating an intensity-modulated fiber optic displacement sensor is experimentally characterized, and the implications regarding sensor design are discussed. Of interest are the intensity distribution of the transmitted optical signal and the relationships between sensor architecture and performance. Particularly, an intensity-modulated sensor's sensitivity, linearity, displacement range, and resolution are functions of the relative positioning of its transmitting and receiving fibers. In this paper, sensor architectures with various combinations of these performance metrics are discussed. A sensor capable of micrometer resolution is reported, and it is concluded that this work could lead to an improved methodology for sensor design.

  12. Glass Difractive Optical Elements (DOEs with complex modulation DLC thin film coated

    Directory of Open Access Journals (Sweden)

    Marina Sparvoli

    2008-09-01

    Full Text Available We developed a complex (amplitude and phase modulation Diffractive Optical Element (DOE with four phase levels, which is based in a glass substrate coated with DLC (Diamond Like Carbon thin film as the amplitude modulator. The DLC film was deposited by magnetron reactive sputtering with a graphite target and methane gas in an optical glass surface. The glass and DLC film roughness were measured using non destructive methods, such as a high step meter, Atomic Force Microscopy and Diffuse Reflectance. Other properties, such as refractive index of both materials were measured. The DOEs were tested using 632.8 nm HeNe laser.

  13. In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

    Institute of Scientific and Technical Information of China (English)

    Ling WANG; Zhi-hua DING; Guo-hua SHI; Yu-dong ZHANG

    2009-01-01

    Fourier-domain rapid scanning optical delay line (RSOD) was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography (TD-OCT) system. Investigation of parameter optimization of RSOD was conducted.Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.

  14. Tunable magneto-optic modulation based on magnetically responsive nanostructured magnetic fluid

    Institute of Scientific and Technical Information of China (English)

    Bai Xue-Kun; Pu Sheng-Li; Wang Lun-Wei; Wang Xiang; Yu Guo-Jun; Ji Hong-Zhu

    2011-01-01

    Magnetic fluid is a kind of functional composite material with nanosized structure and unique optical properties.The tunable magneto-optic modulation of magnetic fluid under external magnetic field,achieved by adjusting the polarization direction of incident light,is investigated theoretically and experimentally in this work.The corresponding modulation depth and response time are obtained.The accompanying mechanisms are clarified by using the theory of dichroism of magnetic fluid and the aggregation/disintegration processes of magnetic particles within magnetic fluid when the external magnetic field turns on/off.

  15. All-optical modulation in dye-doped nematic liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper; Bjarklev, Anders Overgaard;

    2004-01-01

    Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs......) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid...

  16. Externally-Modulated Electro-Optically Coupled Detector Architecture for Nuclear Physics Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Wenze [JLAB; McKisson, John E. [JLAB; Weisenberger, Andrew G. [JLAB; Zhang, Shukui [JLAB; Zorn, Carl J. [JLAB

    2014-06-01

    A new laser-based externally-modulated electro-optically coupled detector (EOCD) architecture is being developed to enable high-density readout for radiation detectors with accurate analog radiation pulse shape and timing preservation. Unlike digital conversion before electro-optical modulation, the EOCD implements complete analog optical signal modulation and multiplexing in its detector front-end. The result is a compact, high performance detector readout that can be both radiation tolerant and immune to magnetic fields. In this work, the feasibility of EOCD was explored by constructing a two-wavelength laser-based externally-modulated EOCD, and testing analog pulse shape preservation and wavelength-division multiplexing (WDM) crosstalk. Comparisons were first made between the corresponding initial pulses and the electro-optically coupled analog pulses. This confirmed an excellent analog pulse preservation over $ sim {hbox {29}}% $ of the modulator’s switching voltage range. Optical spectrum analysis revealed less than $-{hbox {14}}~hbox{dB}$ crosstalk with 1.2 nm WDM wavelength bandgap, and provided insight on experimental conditions that could lead to increased inter-wavelength crosstalk. Further discussions and previous research on the radiation tolerance and magnetic field immunity of the candidate materials were also given, and quantitative device testing is proposed in the future.

  17. Reconfigurable optical interleaver modules with tunable wavelength transfer matrix function using polymer photonics lightwave circuits.

    Science.gov (United States)

    Chen, Changming; Niu, Xiaoyan; Han, Chao; Shi, Zuosen; Wang, Xinbin; Sun, Xiaoqiang; Wang, Fei; Cui, Zhanchen; Zhang, Daming

    2014-08-25

    A transparent reconfigurable optical interleaver module composed of cascaded AWGs-based wavelength-channel-selector/interleaver monolithically integrated with multimode interference (MMI) variable optical attenuators (VOAs) and Mach-Zehnder interferometer (MZI) switch arrays was designed and fabricated using polymer photonic lightwave circuits. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and caldding, respectively. Thermo-optic (TO) tunable wavelength transfer matrix (WTM) function of the module can be achieved for optical routing network. The one-chip transmission loss is ~ 6 dB and crosstalk is less than ~25 dB for transverse-magnetic (TM) mode. The crosstalk and extinction ratio of the MMI VOAs were measured as -15.2 dB and 17.5 dB with driving current 8 mA, respectively. The modulation depth of the TO switches is obtained as ~18.2 dB with 2.2 V bias. Proposed novel interleaver module could be well suited for DWDM optical communication systems.

  18. Research of AGC technology in a digital optical fiber sensing system with PGC modulation and demodulation

    Science.gov (United States)

    Tang, Jianfeng; Xiong, Shuidong; Zhang, Yan

    2014-11-01

    The magnitude of light intensity on the photo-to-electric detector fluctuates all the time in an optic fiber sensing system, because of the influence of various factors in the fiber optic sensing system and from the external environment. As a result of the excessive intensity, the electric signal will be overload after the amplifier circuit with constant enlargement factor, and when the light intensity becames too small, it will reduce the signal-to-noise ratio of the electric signal. Therefore, it is necessary to introduce an automatic gain control (AGC) module into the system, which can insure the electric signal in a reasonable magnitude. In order to solve the problem of optic intensity fluctuating in the optical fiber sensing system with PGC modulation and demodulation, in this paper, firstly, it is analyzed that the impact of different magnitudes of interferential intensity to the PGC demodulation in theory. Secondly, a reasonable control method is put forward and an AGC module based on the AD602 chip is designed and produced. Finally, it is proved that the optic fiber sensor system with an AGC module has strong ability to resist fluctuation of light intensity within 40dB.

  19. Improved performance of traveling wave directional coupler modulator based on electro-optic polymer

    CERN Document Server

    Zhang, Xingyu; Lin, Che-yun; Wang, Alan X; Hosseini, Amir; Lin, Xiaohui; Chen, Ray T

    2014-01-01

    Polymer based electro-optic modulators have shown great potentials in high frequency analog optical links. Existing commercial LiNibO3 Mach-Zehnder modulators have intrinsic drawbacks in linearity to provide high fidelity communication. In this paper, we present the design, fabrication and characterization of a traveling wave directional coupler modulator based on electro-optic polymer, which is able to provide high linearity, high speed, and low optical insertion loss. A silver ground electrode is used to reduce waveguide sidewall roughness due to the scattering of UV light in photolithography process in addition to suppressing the RF loss. A 1-to-2 multi-mode interference 3dB-splitter, a photobleached refractive index taper and a quasi-vertical taper are used to reduce the optical insertion loss of the device. The symmetric waveguide structure of the MMI-fed directional coupler is intrinsically bias-free, and the modulation is obtained at the 3-dB point regardless of the ambient temperature. By achieving lo...

  20. A system for measuring defect induced beam modulation on inertial confinement fusion-class laser optics

    Science.gov (United States)

    Runkel, Mike; Hawley-Fedder, Ruth; Widmayer, Clay; Williams, Wade; Weinzapfel, Carolyn; Roberts, Dave

    2005-12-01

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm2 and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO2 lasers.

  1. High-Speed Electro-Optic Modulator Integrated with Graphene-Boron Nitride Heterostructure and Photonic Crystal Nanocavity

    CERN Document Server

    Gao, Yuanda; Gan, Xuetao; Li, Luozhou; Peng, Cheng; Meric, Inanc; Wang, Lei; Szep, Attila; Walker, Dennis; Hone, James; Englund, Dirk

    2014-01-01

    Nanoscale and power-efficient electro-optic (EO) modulators are essential components for optical interconnects that are beginning to replace electrical wiring for intra- and inter-chip communications. Silicon-based EO modulators show sufficient figures of merits regarding device footprint, speed, power consumption and modulation depth. However, the weak electro-optic effect of silicon still sets a technical bottleneck for these devices, motivating the development of modulators based on new materials. Graphene, a two-dimensional carbon allotrope, has emerged as an alternative active material for optoelectronic applications owing to its exceptional optical and electronic properties. Here, we demonstrate a high-speed graphene electro-optic modulator based on a graphene-boron nitride (BN) heterostructure integrated with a silicon photonic crystal nanocavity. Strongly enhanced light-matter interaction of graphene in a submicron cavity enables efficient electrical tuning of the cavity reflection. We observe a modul...

  2. Bidirectional optical subassembly-shaped 20-Gbit/s compact single-mode four-channel wavelength-division multiplexing optical modules for optical multimedia interfaces

    Science.gov (United States)

    Lim, Kwon-Seob; Yu, Hong-Yeon; Park, Hyoung-Jun; Kang, Hyun Seo; Jang, Jae-Hyung

    2016-06-01

    Low-cost single-mode four-channel optical transmitter and receiver modules using the wavelength-division multiplexing (WDM) method have been developed for long-reach fiber optic applications. The single-mode four-channel WDM optical transmitter and receiver modules consist of two dual-wavelength optical transmitter and receiver submodules, respectively. The integration of two channels in a glass-sealed transistor outline-can package is an effective way to reduce cost and size and to extend the number of channels. The clear eye diagrams with more than about 6 dB of the extinction ratio and the minimum receiver sensitivity of lower than -16 dBm at a bit error rate of 10-12 have been obtained for the transmitter and receiver modules, respectively, at 5 Gbps/channel. The 4K ultrahigh definition contents have been transmitted over a 1-km-long single-mode fiber using a pair of proposed four-channel transmitter optical subassembly and receiver optical subassembly.

  3. Low loss and high speed silicon optical modulator based on a lateral carrier depletion structure.

    Science.gov (United States)

    Marris-Morini, Delphine; Vivien, Laurent; Fédéli, Jean Marc; Cassan, Eric; Lyan, Philippe; Laval, Suzanne

    2008-01-01

    A high speed and low loss silicon optical modulator based on carrier depletion has been made using an original structure consisting of a p-doped slit embedded in the intrinsic region of a lateral pin diode. This design allows a good overlap between the optical mode and carrier density variations. Insertion loss of 5 dB has been measured with a contrast ratio of 14 dB for a 3 dB bandwidth of 10 GHz. PMID:18521165

  4. Potential Upgrade of the CMS Tracker Analog Readout Optical Links using Bandwidth Efficient Digital Modulation

    CERN Document Server

    Dris, Stefanos; Gill, K; Grabit, R; Ricci, D; Troska, J; Vasey, F

    2007-01-01

    The potential application of advanced digital communication schemes in a future upgrade of the CMS Tracker readout optical links is currently being investigated at CERN. We show experimentally that multi-Gbit/s data rates are possible over the current 40 MSamples/s analog optical links by employing techniques similar to those used in ADSL. The concept involves using one or more digitally-modulated sinusoidal carriers in order to make efficient use of the available bandwidth.

  5. Ultrafast optical phase modulation with metallic nanoparticles in ion-implanted bilayer silica

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Torres, C [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, Mexico, DF, 07738 (Mexico); Tamayo-Rivera, L; Silva-Pereyra, H G; Reyes-Esqueda, J A; Rodriguez-Fernandez, L; Crespo-Sosa, A; Cheang-Wong, J C; Oliver, A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510, Mexico, DF (Mexico); Rangel-Rojo, R [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada Apartado Postal 360, Ensenada, BC, 22860 (Mexico); Torres-Martinez, R, E-mail: crstorres@yahoo.com.mx [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada Unidad Queretaro, Instituto Politecnico Nacional, Santiago de Queretaro, Queretaro, 76090 (Mexico)

    2011-09-02

    The nonlinear optical response of metallic-nanoparticle-containing composites was studied with picosecond and femtosecond pulses. Two different types of nanocomposites were prepared by an ion-implantation process, one containing Au nanoparticles (NPs) and the other Ag NPs. In order to measure the optical nonlinearities, we used a picosecond self-diffraction experiment and the femtosecond time-resolved optical Kerr gate technique. In both cases, electronic polarization and saturated absorption were identified as the physical mechanisms responsible for the picosecond third-order nonlinear response for a near-resonant 532 nm excitation. In contrast, a purely electronic nonlinearity was detected at 830 nm with non-resonant 80 fs pulses. Regarding the nonlinear optical refractive behavior, the Au nanocomposite presented a self-defocusing effect, while the Ag one presented the opposite, that is, a self-focusing response. But, when evaluating the simultaneous contributions when the samples are tested as a multilayer sample (silica-Au NPs-silica-Ag NPs-silica), we were able to obtain optical phase modulation of ultra-short laser pulses, as a result of a significant optical Kerr effect present in these nanocomposites. This allowed us to implement an ultrafast all-optical phase modulator device by using a combination of two different metallic ion-implanted silica samples. This control of the optical phase is a consequence of the separate excitation of the nonlinear refracting phenomena exhibited by the separate Au and Ag nanocomposites.

  6. Fiber Optic Broadband Ultrasonic Probe for Virtual Biopsy: Technological Solutions

    OpenAIRE

    Biagi, E.; Cerbai, S.; Masotti, L.; L. Belsito; A. RONCAGLIA; Masetti, G.; N. Speciale

    2010-01-01

    An ultrasonic probe was developed by using, in conjunction, optoacoustic and acousto-optic devices based on fiber optic technology. The intrinsic high frequency and wide bandwidth associated both to the opto-acoustic source and to the acousto-optic receiving element could open a way towards a “virtual biopsy” of biological tissue. A Micro-Opto-Mechanical-System (MOMS) approach is proposed to realize the broadband ultrasonic probe on micromachined silicon frames suited to be mounted on the tip...

  7. Enhanced performance of semiconductor optical amplifier at high direct modulation speed with birefringent fiber loop

    Directory of Open Access Journals (Sweden)

    K. E. Zoiros

    2014-07-01

    Full Text Available We employ a birefringent fiber loop (BFL for enhancing the performance of a semiconductor optical amplifier (SOA which is directly modulated. By properly exploiting the BFL comb-like spectral response, we show that the SOA can be directly modulated at a data rate which is more than five times faster than that enabled by the SOA electrical bandwidth. The experimental results, which include chirp measurements, demonstrate the significant improvements achieved in the performance of the directly modulated SOA with the help of the BFL.

  8. Generation of Optical Millimeter Wave Using Two Cascaded Polarization Modulators Based on Frequency Octupling Without Filtering

    Science.gov (United States)

    Yang, Yang; Ma, Jianxin; Zhang, Ruijiao; Xin, Xiangjun; Zhang, Junyi

    2015-11-01

    An approach to generate an optical millimeter wave is introduced with frequency octupling using two cascaded polarization modulators followed by polarizers, respectively. By adjusting the modulation indexes of polarization modulators, only the ±4th-order sidebands are generated with a pure spectrum. Since no filter is needed, the proposed technique can be used to generate a frequency-tunable millimeter wave with a large frequency-tunable range. To prove the feasibility of the proposed approach, a simulation is conducted to generate an 80-GHz millimeter wave, and then its transmission performance is checked.

  9. Precision 3-D microscopy with intensity modulated fibre optic scanners

    Science.gov (United States)

    Olmos, P.

    2016-01-01

    Optical 3-D imagers constitute a family of precision and useful instruments, easily available on the market in a wide variety of configurations and performances. However, besides their cost they usually provide an image of the object (i.e. a more or less faithful representation of the reality) instead of a truly object's reconstruction. Depending on the detailed working principles of the equipment, this reconstruction may become a challenging task. Here a very simple yet reliable device is described; it is able to form images of opaque objects by illuminating them with an optical fibre and collecting the reflected light with another fibre. Its 3-D capability comes from the spatial filtering imposed by the fibres together with their movement (scanning) along the three directions: transversal (surface) and vertical. This unsophisticated approach allows one to model accurately the entire optical process and to perform the desired reconstruction, finding that information about the surface which is of interest: its profile and its reflectance, ultimately related to the type of material.

  10. Optically pumped terahertz wave modulation in MoS2-Si heterostructure metasurface

    Science.gov (United States)

    Zheng, Wei; Fan, Fei; Chen, Meng; Chen, Sai; Chang, Sheng-Jiang

    2016-07-01

    An optically pumped terahertz (THz) modulator based on a MoS2-Si heterostructure metasurface are fabricated and investigated in this paper. The THz wave modulation in MoS2 metasurface has been demonstrated by THz time domain spectroscopy experiment and numerical simulation, which can reach over 90% under the continuous wave laser pumping of 4W/cm2 power density. Importantly, the catalysis of photocarrier generation in MoS2-Si heterostructure has been proved by the comparsion between the modulation depth of metasurface with and without MoS2 nanosheet under the same pumping power, and we found that the strcuture of metasurface and polariztion direction can also influence the photocarrier density in MoS2 metasurface. This novel THz modulator based on 2D material has a high effective modulation on THz waves under a low pumping power, which has a bright potential in THz applications.

  11. LIGHT MODULATION: Ultrafast optical modulators based on the nonlinear optical response of an electron—hole plasma

    Science.gov (United States)

    Ermolenko, M. V.; Stankevich, V. V.; Buganov, O. V.; Tikhomirov, S. A.; Ganonenko, S. V.; Kuznetsov, P. I.; Yakushcheva, G. G.

    2009-04-01

    The nonlinear optical properties of multilayer heterostructures based on zinc chalcogenides are studied. Rapid variations in the reflection and transmission of samples excited by ultrashort laser pulses are demonstrated. The characteristic relaxation times of the induced nonlinearity are 2-5 ps and are almost independent within the experimental error on the excitation energy and temperature of a sample.

  12. Optically Modulated Bistability in Quantum Dot Resonant Tunneling Diodes

    Science.gov (United States)

    Weng, Qian-Chun; An, Zheng-Hua; Hou, Ying; Zhu, Zi-Qiang

    2013-04-01

    InAs quantum dots are introduced into resonant tunneling diodes to study the electronic transport behavior, and a wide bistability (ΔV ~ 0.8 V) is observed in the negative differential resistance region. Based on an analytic model, we attribute the observed distinct bistability of a resonant tunneling diodes with quantum dots to the feedback dependence of energy of the electron-storing quantum dots on the tunneling current density. Meanwhile, we find that this wide bistable region can be modulated sensitively by light illumination and becomes narrower with increasing light intensity. Our results suggest that the present devices can be potentially used as sensitive photodetectors in optoelectronic fields.

  13. Laser modulated scattering as a nondestructive evaluation tool for optical surfaces and thin film coatings

    Energy Technology Data Exchange (ETDEWEB)

    Feit, M D; Kozlowski, M R; Rubenchik, A M; Sheehan, L; Wu, Z L

    1999-12-22

    Laser modulated scattering (LMS) is introduced as a non-destructive evaluation tool for defect inspection and characterization of optical surfaces and thin film coatings. This technique is a scatter sensitive version of the well-known photothermal microscopy (PTM) technique. It allows simultaneous measurement of the DC and AC scattering signals of a probe laser beam from an optical surface. By comparison between the DC and AC scattering signals, one can differentiate absorptive defects from non-absorptive ones. This paper describes the principle of the LMS technique and the experimental setup, and illustrates examples on using LMS as a tool for nondestructive evaluation of high quality optics.

  14. Integrated Optical Heterodyne Interferometer in Lithium Niobate

    Science.gov (United States)

    Rubiyanto, A.; Herrmann, H.; Ricken, R.; Tian, F.; Sohler, W.

    A high performance integrated acousto-optical heterodyne interferometer has been developed for vibration measurement. All components including an acousto-optical TE-TM mode converters, two electro-optical TE-TM converters, two polarization splitters and two phase shifters are integrated on a X-cut Lithium Niobate substrate. The fully packaged optical integrated circuit (optical-IC) coupling with three fibers optics pigtails gave a signal-to-noise ratio of 69 dB with at 3 kHz bandwidth by using a commercial DFB laser diode as a light source with 1561 nm emission wavelength and a PIN-FET balanced receiver.

  15. All-optical wavelength conversion and signal regeneration using an electroabsorption modulator

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Bischoff, Svend; Mørk, Jesper

    1999-01-01

    All-optical wavelength conversion in an InGaAsP quantum well electroabsorption modulator is studied at different bit-rates. We present theoretical results showing wavelength conversion efficiency in agreement with existing experimental results, and signal regeneration capability is demonstrated....

  16. Deep sea tests of a prototype of the KM3NeT digital optical module

    NARCIS (Netherlands)

    Adrian-Martinez, S.; Ageron, M.; Aharonian, F.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; de Asmundis, R.; Balasi, K.; Band, H.; Barbarino, G.; Barbarito, E.; Barbato, F.; Baret, B.; Baron, S.; Belias, A.; Berbee, E.; van den Berg, A. M.; Berkien, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Bianucci, S.; Billault, M.; Birbas, A.; Rookhuizen, H. Boer; Bormuth, R.; Bouche, V.; Bouhadef, B.; Bourlis, G.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Caruso, F.; Cecchini, S.; Ceres, A.; Cereseto, R.; Champion, C.; Chateau, F.; Chiarusi, T.; Christopoulou, B.; Circella, M.; Classen, L.; Cocimano, R.; Colonges, S.; Coniglione, R.; Cosquer, A.; Costa, M.; Coyle, P.; Creusot, A.; Curtil, C.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Rosa, G.; Deniskina, N.; Destelle, J-J.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti Hasankiadeh, Qader; Drakopoulou, E.; Drouhin, D.; Drury, L.; Durand, D.; Eberl, T.; Eleftheriadis, C.; Elsaesser, D.; Enzenhoefer, A.; Fermani, P.; Fusco, L. A.; Gajana, D.; Gal, T.; Galata, S.; Gallo, F.; Garufi, F.; Gebyehu, M.; Giordano, V.; Gizani, N.; Ruiz, R. Gracia; Graf, K.; Grasso, R.; Grella, G.; Grmek, A.; Habel, R.; van Haren, H.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernandez-Rey, J. J.; Herold, B.; Hevinga, M. A.; van der Hoek, M.; Hofestaedt, J.; Hogenbirk, J.; Hugon, C.; Hoessl, J.; Imbesi, M.; James, C.; Jansweijer, P.; Jochum, J.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Kappos, E.; Katz, U.; Kavatsyuk, O.; Keller, P.; Kieft, G.; Koffeman, E.; Kok, H.; Kooijman, P.; Koopstra, J.; Korporaal, A.; Kouchner, A.; Koutsoukos, S.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Le Provost, H.; Leisos, A.; Lenis, D.; Leonora, E.; Clark, M. Lindsey; Liolios, A.; Llorens Alvarez, C. D.; Loehner, H.; Lo Presti, D.; Louis, F.; Maccioni, E.; Mannheim, K.; Manolopoulos, K.; Margiotta, A.; Maris, O.; Markou, C.; Martinez-Mora, J. A.; Martini, A.; Masullo, R.; Michael, T.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C.; Mongelli, M.; Morganti, M.; Mos, S.; Moudden, Y.; Musico, P.; Musumeci, M.; Nicolaou, C.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papageorgiou, K.; Papaikonomou, A.; Papaleo, R.; Pavalas, G. E.; Peek, H.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Petridou, C.; Piattelli, P.; Pikounis, K.; Popa, V.; Pradier, Th; Priede, M.; Puehlhofer, G.; Pulvirenti, S.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rapidis, P. A.; Razis, P.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rovelli, A.; Royon, J.; Saldana, M.; Samtleben, D. F. E.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Savvidis, I.; Schmelling, J.; Schnabel, J.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Siotis, I.; Sipala, V.; Solazzo, M.; Spitaleri, A.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stolarczyk, T.; Stransky, D.; Taiuti, M.; Terreni, G.; Tezier, D.; Theraube, S.; Thompson, L. F.; Timmer, P.; Trapierakis, H. I.; Trasatti, L.; Trovato, A.; Tselengidou, M.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Vernin, P.; Viola, S.; Vivolo, D.; Werneke, P.; Wiggers, L.; Wilms, J.; de Wolf, E.; van Wooning, R. H. L.; Yatkin, K.; Zachariadou, K.; Zonca, E.; Zornoza, J. D.; Zuniga, J.; Zwart, A.

    2014-01-01

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deepwaters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has b

  17. Magnetic field topographical survey by magneto-optical space-time light modulators

    Science.gov (United States)

    Levy, Sergey V.; Ostrovsky, Andrey S.; Agalidy, Yu. S.

    1993-12-01

    Utilization of magneto-optical spacing light modulators based on Bi-substituted monocrystalline ferrite-garnet films for spatially distributed magnetic field measurements is discussed. Numerous variants of magnetic field topographical survey for different types (audio & video ...) of magnetic signalogramms geometrical parameters control are described. Special usages for magnetic signalogramms criminalistics examination and faint amplitude signalogramms visualization are described too.

  18. Optically envelope detected QAM and QPSK RF modulated signals in hybrid wireless-fiber systems

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Prince, Kamau; Seoane, Jorge;

    2009-01-01

    from a 1.6 GHz carrier frequency to an IF at 500 MHz, requiring no high frequency local oscillator and mixer at the remote base station. This result proves the feasibility of optical envelope detection for complex modulation formats of RF signals for hybrid wireless-fiber transmission links....

  19. Indium-Tin-Oxide for High-performance Electro-optic Modulation

    Directory of Open Access Journals (Sweden)

    Ma Zhizhen

    2015-06-01

    Full Text Available Advances in opto-electronics are often led by discovery and development of materials featuring unique properties. Recently, the material class of transparent conductive oxides (TCO has attracted attention for active photonic devices on-chip. In particular, indium tin oxide (ITO is found to have refractive index changes on the order of unity. This property makes it possible to achieve electrooptic modulation of sub-wavelength device scales, when thin ITO films are interfaced with optical light confinement techniques such as found in plasmonics; optical modes are compressed to nanometer scale to create strong light-matter interactions. Here we review efforts towards utilizing this novel material for high performance and ultra-compact modulation. While high performance metrics are achieved experimentally, there are open questions pertaining to the permittivity modulation mechanism of ITO. Finally, we review a variety of optical and electrical properties of ITO for different processing conditions, and show that ITO-based plasmonic electro-optic modulators have the potential to significantly outperform diffractionlimited devices.

  20. Indium-Tin-Oxide for High-performance Electro-optic Modulation

    Science.gov (United States)

    Ma, Zhizhen; Li, Zhuoran; Liu, Ke; Ye, Chenran; Sorger, Volker J.

    2015-06-01

    Advances in opto-electronics are often led by discovery and development of materials featuring unique properties. Recently, the material class of transparent conductive oxides (TCO) has attracted attention for active photonic devices on-chip. In particular, indium tin oxide (ITO) is found to have refractive index changes on the order of unity. This property makes it possible to achieve electrooptic modulation of sub-wavelength device scales, when thin ITO films are interfaced with optical light confinement techniques such as found in plasmonics; optical modes are compressed to nanometer scale to create strong light-matter interactions. Here we review efforts towards utilizing this novel material for high performance and ultra-compact modulation. While high performance metrics are achieved experimentally, there are open questions pertaining to the permittivity modulation mechanism of ITO. Finally, we review a variety of optical and electrical properties of ITO for different processing conditions, and show that ITO-based plasmonic electro-optic modulators have the potential to significantly outperform diffractionlimited devices.

  1. Ultrafast all-optical modulation using a photonic-crystal Fano structure with broken symmetry

    DEFF Research Database (Denmark)

    Yu, Yi; Hu, Hao; Oxenløwe, Leif Katsuo;

    2015-01-01

    We experimentally demonstrate ultrafast all-optical modulation using an ultracompact InP photonic-crystal Fanostructure. In contrast to symmetric configurations previously considered, the use of a structure with broken symmetryin combination with a well-engineered Fano resonance is shown to...

  2. Research of electro-optical modulators usage for microwave photonic filters

    OpenAIRE

    Morozov, Oleg G.; Sadeev, T. S.; Talipov, A. A.

    2014-01-01

    We analyze the most effective way to obtain microwave-photonic filter’s coefficients, specifically implemented by electro-optical modulators. These devices are attractive to obtain desired number and sign of coefficients which results in high tunability and reconfigurability of filters. One has to decide which device will be the most appropriate in obtaining desired frequency response of the filter.

  3. Characterisation of a MQW electroabsorption modulator as an all-optical demultiplexer

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Romstad, Francis Pascal; Tersigni, Andrea;

    2001-01-01

    A detailed experimental investigation of the all-optical switching properties of an InGaAsP MQW electroabsorption modulator has been performed. Using high pump pulse energies and high reverse bias settings, switching windows were demonstrated with extinction ratios up to 25 dB and widths down to ...

  4. Broadband microwave phase shifter based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2009-01-01

    We present a scheme to achieve tunable ~180 degrees microwave phase shifts at frequencies exceeding 100 GHz based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers.......We present a scheme to achieve tunable ~180 degrees microwave phase shifts at frequencies exceeding 100 GHz based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers....

  5. Optical modulation of astrocyte network using ultrashort pulsed laser

    Science.gov (United States)

    Yoon, Jonghee; Ku, Taeyun; Chong, Kyuha; Ryu, Seung-Wook; Choi, Chulhee

    2012-03-01

    Astrocyte, the most abundant cell type in the central nervous system, has been one of major topics in neuroscience. Even though many tools have been developed for the analysis of astrocyte function, there has been no adequate tool that can modulates astrocyte network without pharmaceutical or genetic interventions. Here we found that ultrashort pulsed laser stimulation can induce label-free activation of astrocytes as well as apoptotic-like cell death in a dose-dependent manner. Upon irradiation with high intensity pulsed lasers, the irradiated cells with short exposure time showed very rapid mitochondria fragmentation, membrane blebbing and cytoskeletal retraction. We applied this technique to investigate in vivo function of astrocyte network in the CNS: in the aspect of neurovascular coupling and blood-brain barrier. We propose that this noninvasive technique can be widely applied for in vivo study of complex cellular network.

  6. All-plasmonic Mach-Zehnder modulator enabling optical high-speed communication at the microscale

    Science.gov (United States)

    Haffner, C.; Heni, W.; Fedoryshyn, Y.; Niegemann, J.; Melikyan, A.; Elder, D. L.; Baeuerle, B.; Salamin, Y.; Josten, A.; Koch, U.; Hoessbacher, C.; Ducry, F.; Juchli, L.; Emboras, A.; Hillerkuss, D.; Kohl, M.; Dalton, L. R.; Hafner, C.; Leuthold, J.

    2015-08-01

    Optical modulators encode electrical signals to the optical domain and thus constitute a key element in high-capacity communication links. Ideally, they should feature operation at the highest speed with the least power consumption on the smallest footprint, and at low cost. Unfortunately, current technologies fall short of these criteria. Recently, plasmonics has emerged as a solution offering compact and fast devices. Yet, practical implementations have turned out to be rather elusive. Here, we introduce a 70 GHz all-plasmonic Mach-Zehnder modulator that fits into a silicon waveguide of 10 μm length. This dramatic reduction in size by more than two orders of magnitude compared with photonic Mach-Zehnder modulators results in a low energy consumption of 25 fJ per bit up to the highest speeds. The technology suggests a cheap co-integration with electronics.

  7. Deep sea tests of a prototype of the KM3NeT digital optical module

    CERN Document Server

    Adrián-Martínez, S; Aharonian, F; Aiello, S; Albert, A; Ameli, F; Anassontzis, E G; Anghinolfi, M; Anton, G; Anvar, S; Ardid, M; de Asmundis, R; Band, H; Barbarino, G; Barbarito, E; Barbato, F; Baret, B; Baron, S; Belias, A; Berbee, E; Berg, A M van den; Berkien, A; Bertin, V; Beurthey, S; van Beveren, V; Beverini, N; Biagi, S; Bianucci, S; Billault, M; Birbas, A; Rookhuizen, H Boer; Bormuth, R; Bouche, V; Bouhadef, B; Bourlis, G; Bouwhuis, M; Bozza, C; Bruijn, R; Brunner, J; Cacopardo, G; Caillat, L; Calamai, M; Calvo, D; Capone, A; Caramete, L; Caruso, F; Cecchini, S; Ceres, A; Cereseto, R; Champion, C; Chateau, F; Chiarusi, T; Christopoulou, B; Circella, M; Classen, L; Cocimano, R; Colonges, S; Coniglione, R; Cosquer, A; Costa, M; Coyle, P; Creusot, A; Curtil, C; Cuttone, G; D'Amato, C; D'Amico, A; De Bonis, G; De Rosa, G; Deniskina, N; Destelle, J -J; Distefano, C; Donzaud, C; Dornic, D; Dorosti-Hasankiadeh, Q; Drakopoulou7, E; Drouhin, D; Drury, L; Durand, D; Eberl, T; Eleftheriadis, C; Elsaesser, D; Enzenhofer, A; Fermani, P; Fusco, L A; Gajana, D; Gal, T; Galata, S; Gallo, F; Garufi, F; Gebyehu, M; Giordano, V; Gizani, N; Ruiz, R Gracia; Graf, K; Grasso, R; Grella, G; Grmek, A; Habel, R; van Haren, H; Heid, T; Heijboer, A; Heine, E; Henry, S; Hernandez-Rey, J J; Herold, B; Hevinga, M A; van der Hoek, M; Hofestadt, J; Hogenbirk, J; Hugon, C; Hosl, J; Imbesi, M; James, C; Jansweijer, P; Jochum, J; de Jong, M; Kadler, M; Kalekin, O; Kappes, A; Kappos, E; Katz, U; Kavatsyuk, O; Keller, P; Kieft, G; Koffeman, E; Kok, H; Kooijman, P; Koopstra, J; Korporaal, A; Kouchner, A; Koutsoukos, S; Kreykenbohm, I; Kulikovskiy, V; Lahmann, R; Lamare, P; Larosa, G; Lattuada, D; Provost, H Le; Leisos, A; Lenis, D; Leonora, E; Clark, M Lindsey; Liolios, A; Alvarez, C D Llorens; Lohner, H; Presti, D Lo; Louis, F; Maccioni, E; Mannheim, K; Manolopoulos, K; Margiotta, A; Maris, O; Markou, C; Martinez-Mora, J A; Martini, A; Masullo, R; Michael, T; Migliozzi, P; Migneco, E; Miraglia, A; Mollo, C; Mongelli, M; Morganti, M; Mos, S; Moudden, Y; Musico, P; Musumeci, M; Nicolaou, C; Nicolau, C A; Orlando, A; Orzelli, A; Papageorgiou, K; Papaikonomou, A; Papaleo, R; Pavalas, G E; Peek, H; Pellegrino, C; Pellegriti, M G; Perrina, C; Petridou, C; Piattelli, P; Popa, V; Pradier, Th; Priede, M; Puhlhofer, G; Pulvirenti, S; Racca, C; Raffaelli, F; Randazzo, N; Rapidis, P A; Razis, P; Real, D; Resvanis, L; Reubelt, J; Riccobene, G; Rovelli, A; Royon, J; Saldana, M; Samtleben, D F E; Sanguineti, M; Santangelo, A; Sapienza, P; Savvidis, I; Schmelling, J; Schnabel, J; Sedita, M; Seitz, T; Sgura, I; Simeone, F; Siotis, I; Sipala, V; Solazzo, M; Spitaleri, A; Spurio, M; Steijger, J; Stolarczyk, T; Stransky, D; Taiuti, M; Terreni, G; Tezier, D; Theraube, S; Thompson, L F; Timmer, P; Trapierakis, H I; Trasatti, L; Trovato, A; Tselengidou, M; Tsirigotis, A; Tzamarias, S; Tzamariudaki, E; Vallage, B; Van Elewyck, V; Vermeulen, J; Vernin, P; Viola, S; Vivolo, D; Werneke, P; Wiggers, L; Wilms, J; de Wolf, E; van Wooning, R H L; Yatkin, K; Zachariadou, K; Zonca, E; Zornoza, J D; Zúñiga, J; Zwart, A

    2014-01-01

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same $^{40}$K decay and the localization bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions.

  8. Deep sea tests of a prototype of the KM3NeT digital optical module

    Energy Technology Data Exchange (ETDEWEB)

    Adrian-Martinez, S.; Ardid, M.; Llorens Alvarez, C.D.; Saldana, M. [Universitat Politecnica de Valencia, Instituto de Investigacion para la Gestion Integrada de las Zonas Costeras, Gandia (Spain); Ageron, M.; Bertin, V.; Beurthey, S.; Billault, M.; Brunner, J.; Caillat, L.; Cosquer, A.; Coyle, P.; Curtil, C.; Destelle, J.J.; Dornic, D.; Gallo, F.; Henry, S.; Keller, P.; Lamare, P.; Royon, J.; Solazzo, M.; Tezier, D.; Theraube, S.; Yatkin, K. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Aharonian, F.; Drury, L. [DIAS, Dublin (Ireland); Aiello, S.; Giordano, V.; Leonora, E.; Randazzo, N.; Sipala, V. [INFN, Sezione di Catania, Catania (Italy); Albert, A.; Drouhin, D.; Racca, C. [GRPHE, Universite de Haute Alsace, IUT de Colmar, Colmar (France); Ameli, F.; De Bonis, G.; Nicolau, C.A.; Simeone, F. [INFN, Sezione di Roma, Rome (Italy); Anassontzis, E.G. [National and Kapodistrian University of Athens, Deparment of Physics, Athens (Greece); Anghinolfi, M.; Cereseto, R.; Hugon, C.; Kulikovskiy, V.; Musico, P.; Orzelli, A. [INFN, Sezione di Genova, Genoa (Italy); Anton, G.; Classen, L.; Eberl, T.; Enzenhoefer, A.; Gal, T.; Graf, K.; Heid, T.; Herold, B.; Hofestaedt, J.; Hoessl, J.; James, C.; Kalekin, O.; Kappes, A.; Katz, U.; Lahmann, R.; Reubelt, J.; Schnabel, J.; Seitz, T.; Stransky, D.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Anvar, S.; Chateau, F.; Durand, D.; Le Provost, H.; Louis, F.; Moudden, Y.; Zonca, E. [CEA, Irfu/Sedi, Centre de Saclay, Gif-sur-Yvette (France); Asmundis, R. de; Deniskina, N.; Migliozzi, P.; Mollo, C. [INFN, Sezione di Napoli, Naples (Italy); Balasi, K.; Drakopoulou, E.; Markou, C.; Pikounis, K.; Siotis, I.; Stavropoulos, G.; Tzamariudaki, E. [Institute of Nuclear Physics, NCSR ' ' Demokritos' ' , Athens (Greece); Band, H.; Berbee, E.; Berkien, A.; Beveren, V. van; Boer Rookhuizen, H.; Bouwhuis, M.; Gajana, D.; Gebyehu, M.; Heijboer, A.; Heine, E.; Hoek, M. van der; Hogenbirk, J.; Jansweijer, P.; Kieft, G.; Kok, H.; Koopstra, J.; Korporaal, A.; Michael, T.; Mos, S.; Peek, H.; Schmelling, J.; Steijger, J.; Timmer, P.; Vermeulen, J.; Werneke, P.; Wiggers, L.; Zwart, A. [Nikhef, Amsterdam (Netherlands); Barbarino, G.; Barbato, F.; De Rosa, G.; Garufi, F.; Vivolo, D. [INFN, Sezione di Napoli, Naples (Italy); Universita ' Federico II' , Dipartimento di Fisica, Naples (Italy); Barbarito, E.; Ceres, A.; Circella, M.; Mongelli, M.; Sgura, I. [INFN, Sezione di Bari, Bari (Italy); Baret, B.; Baron, S.; Champion, C.; Colonges, S.; Creusot, A.; Galata, S.; Gracia Ruiz, R.; Kouchner, A.; Lindsey Clark, M.; Van Elewyck, V. [APC,Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Belias, A.; Rapidis, P.A.; Trapierakis, H.I. [Institute of Nuclear Physics, NCSR ' ' Demokritos' ' , Athens (Greece); National Observatory of Athens, NESTOR Institute for Deep Sea Research, Technology, and Neutrino Astroparticle Physics, Pylos (Greece); Berg, A.M. van den; Dorosti-Hasankiadeh, Q.; Hevinga, M.A.; Kavatsyuk, O.; Loehner, H.; Wooning, R.H.L. van [KVI-CART, University of Groningen, Groningen (Netherlands); Beverini, N. [INFN, Sezione di Pisa, Pisa (Italy); Universita di Pisa, Dipertimento di Fisica, Pisa (Italy); Biagi, S.; Cecchini, S.; Fusco, L.A.; Margiotta, A.; Spurio, M. [INFN, Sezione di Bologna, Bologna (Italy); Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); Bianucci, S.; Bouhadef, B.; Calamai, M.; Morganti, M.; Raffaelli, F.; Terreni, G. [Universita di Pisa, Dipertimento di Fisica, Pisa (Italy); Birbas, A.; Bourlis, G.; Christopoulou, B.; Gizani, N.; Leisos, A.; Lenis, D.; Tsirigotis, A.; Tzamarias, S. [Hellenic Open University, School of Science and Technology, Patras (Greece); Bormuth, R.; Jong, M. de; Samtleben, D.F.E. [Nikhef, Amsterdam (Netherlands); Leiden University, Leiden Institute of Physics, Leiden (Netherlands); Bouche, V.; Fermani, P.; Masullo, R.; Perrina, C. [INFN, Sezione di Roma, Rome (Italy); Universita di Roma La Sapienza, Dipartimento di Fisica, Rome (Italy); Bozza, C.; Grella, G. [Universita ' Federico II' , Dipartimento di Fisica, Naples (Italy); Universita di Salerno, Dipartimento di Fisica, Fisciano (Italy); Bruijn, R.; Koffeman, E.; Wolf, E. de [Nikhef, Amsterdam (Netherlands); University of Amsterdam, Institute of Physics, Amsterdam (Netherlands); Cacopardo, G.; Caruso, F.; Cocimano, R.; Coniglione, R.; Costa, M.; Cuttone, G.; D' Amato, C.; D' Amico, A.; Distefano, C.; Grasso, R.; Grmek, A.; Imbesi, M.; Larosa, G.; Lattuada, D.; Migneco, E.; Miraglia, A.; Musumeci, M.; Orlando, A.; Papaleo, R.; Pellegrino, C.; Pellegriti, M.G.; Piattelli, P. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Collaboration: KM3NeT Collaboration; and others

    2014-09-15

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same {sup 40}K decay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions. (orig.)

  9. Deep sea tests of a prototype of the KM3NeT digital optical module

    International Nuclear Information System (INIS)

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same 40K decay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions. (orig.)

  10. An all-optical modulation method in sub-micron scale.

    Science.gov (United States)

    Yang, Longzhi; Pei, Chongyang; Shen, Ao; Zhao, Changyun; Li, Yan; Li, Xia; Yu, Hui; Li, Yubo; Jiang, Xiaoqing; Yang, Jianyi

    2015-01-01

    We report a theoretical study showing that by utilizing the illumination of an external laser, the Surface Plasmon Polaritons (SPP) signals on the graphene sheet can be modulated in the sub-micron scale. The SPP wave can propagate along the graphene in the middle infrared range when the graphene is properly doped. Graphene's carrier density can be modified by a visible laser when the graphene sheet is exfoliated on the hydrophilic SiO2/Si substrate, which yields an all-optical way to control the graphene's doping level. Consequently, the external laser beam can control the propagation of the graphene SPP between the ON and OFF status. This all-optical modulation effect is still obvious when the spot size of the external laser is reduced to 400 nm while the modulation depth is as high as 114.7 dB/μm. PMID:25777581

  11. Efficient graphene based electro-optical modulator enabled by interfacing plasmonic slot and silicon waveguides

    CERN Document Server

    Ding, Yunhong; Zhu, Xiaolong; Hu, Hao; Bozhevolnyi, Sergey I; Oxenløwe, Leif Katsuo; Mortensen, N Asger; Xiao, Sanshui

    2016-01-01

    Graphene based electro-absorption modulators involving dielectric optical waveguides or resonators have been widely explored, suffering however from weak graphene-light interaction due to poor overlap of optical fields with graphene layers. Surface plasmon polaritons enable light concentration within subwavelength regions opening thereby new avenues for strengthening graphene-light interactions. Through careful optimization of plasmonic slot waveguides, we demonstrate efficient and compact graphene-plasmonic modulators that are interfaced with silicon waveguides and thus fully integrated in the silicon-on-insulator platform. By advantageously exploiting low-loss plasmonic slot-waveguide modes, which weakly leak into a substrate while feature strong fields within the two-layer-graphene covered slots in metal, we have successfully achieved a tunability of 0.13 dB/{\\mu}m for our fabricated graphene-plasmonic waveguide modulators with low insertion loss, which significantly exceeds the performance of previously r...

  12. Deep sea tests of a prototype of the KM3NeT digital optical module

    Science.gov (United States)

    Adrián-Martínez, S.; Ageron, M.; Aharonian, F.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; de Asmundis, R.; Balasi, K.; Band, H.; Barbarino, G.; Barbarito, E.; Barbato, F.; Baret, B.; Baron, S.; Belias, A.; Berbee, E.; van den Berg, A. M.; Berkien, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Bianucci, S.; Billault, M.; Birbas, A.; Boer Rookhuizen, H.; Bormuth, R.; Bouché, V.; Bouhadef, B.; Bourlis, G.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Caruso, F.; Cecchini, S.; Ceres, A.; Cereseto, R.; Champion, C.; Château, F.; Chiarusi, T.; Christopoulou, B.; Circella, M.; Classen, L.; Cocimano, R.; Colonges, S.; Coniglione, R.; Cosquer, A.; Costa, M.; Coyle, P.; Creusot, A.; Curtil, C.; Cuttone, G.; D'Amato, C.; D'Amico, A.; De Bonis, G.; De Rosa, G.; Deniskina, N.; Destelle, J.-J.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Drury, L.; Durand, D.; Eberl, T.; Eleftheriadis, C.; Elsaesser, D.; Enzenhöfer, A.; Fermani, P.; Fusco, L. A.; Gajana, D.; Gal, T.; Galatà, S.; Gallo, F.; Garufi, F.; Gebyehu, M.; Giordano, V.; Gizani, N.; Gracia Ruiz, R.; Graf, K.; Grasso, R.; Grella, G.; Grmek, A.; Habel, R.; van Haren, H.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Herold, B.; Hevinga, M. A.; van der Hoek, M.; Hofestädt, J.; Hogenbirk, J.; Hugon, C.; Hößl, J.; Imbesi, M.; James, C.; Jansweijer, P.; Jochum, J.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Kappos, E.; Katz, U.; Kavatsyuk, O.; Keller, P.; Kieft, G.; Koffeman, E.; Kok, H.; Kooijman, P.; Koopstra, J.; Korporaal, A.; Kouchner, A.; Koutsoukos, S.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lattuada, D.; Le Provost, H.; Leisos, A.; Lenis, D.; Leonora, E.; Lindsey Clark, M.; Liolios, A.; Llorens Alvarez, C. D.; Löhner, H.; Lo Presti, D.; Louis, F.; Maccioni, E.; Mannheim, K.; Manolopoulos, K.; Margiotta, A.; Mariş, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Masullo, R.; Michael, T.; Migliozzi, P.; Migneco, E.; Miraglia, A.; Mollo, C.; Mongelli, M.; Morganti, M.; Mos, S.; Moudden, Y.; Musico, P.; Musumeci, M.; Nicolaou, C.; Nicolau, C. A.; Orlando, A.; Orzelli, A.; Papageorgiou, K.; Papaikonomou, A.; Papaleo, R.; Păvălaş, G. E.; Peek, H.; Pellegrino, C.; Pellegriti, M. G.; Perrina, C.; Petridou, C.; Piattelli, P.; Pikounis, K.; Popa, V.; Pradier, Th.; Priede, M.; Pühlhofer, G.; Pulvirenti, S.; Racca, C.; Raffaelli, F.; Randazzo, N.; Rapidis, P. A.; Razis, P.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rovelli, A.; Royon, J.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Savvidis, I.; Schmelling, J.; Schnabel, J.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Siotis, I.; Sipala, V.; Solazzo, M.; Spitaleri, A.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stolarczyk, T.; Stransky, D.; Taiuti, M.; Terreni, G.; Tézier, D.; Théraube, S.; Thompson, L. F.; Timmer, P.; Trapierakis, H. I.; Trasatti, L.; Trovato, A.; Tselengidou, M.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Vernin, P.; Viola, S.; Vivolo, D.; Werneke, P.; Wiggers, L.; Wilms, J.; de Wolf, E.; van Wooning, R. H. L.; Yatkin, K.; Zachariadou, K.; Zonca, E.; Zornoza, J. D.; Zúñiga, J.; Zwart, A.

    2014-09-01

    The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deep waters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same $^{40}$K decay and the localization bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions.

  13. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    Science.gov (United States)

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules. PMID:27410896

  14. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    Science.gov (United States)

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules.

  15. Characterisation and efficient simulation of thermal phenomena in SIMOX thermo-optic phase modulators

    CERN Document Server

    Clark, S A

    2001-01-01

    device has been designed to minimize power requirements, 3dB bandwidths in excess of 1kHz have been achieved for less than 10mW of drive power. A basic set of design parameters is developed which allow estimation of bandwidth and power requirements based on an initial knowledge of the material system and the intended modulator architecture. Silicon can be very effectively exploited in integrated optics due to its well-defined process chemistry and the availability of techniques developed primarily for the semiconductor industry which allow control over dimensions and the creation of arbitrary two dimensional structures with great precision and repeatability. In this thesis the complete design and simulation of thermo-optic phase modulators, realised in silicon-on-insulator (SOI), is presented. Since material thermal and optical parameters vary with temperature, anomalous departure between first-order theory and experimentation can exist when operating under conditions whereby material parameters are markedly ...

  16. Quantitative security evaluation of optical encryption using hybrid phase- and amplitude-modulated keys.

    Science.gov (United States)

    Sarkadi, Tamás; Koppa, Pál

    2012-02-20

    In the increasing number of system approaches published in the field of optical encryption, the security level of the system is evaluated by qualitative and empirical methods. To quantify the security of the optical system, we propose to use the equivalent of the key length routinely used in algorithmic encryption. We provide a calculation method of the number of independent keys and deduce the binary key length for optical data encryption. We then investigate and optimize the key length of the combined phase- and amplitude-modulated key encryption in the holographic storage environment, which is one of the promising solutions for the security enhancement of single- and double-random phase-encoding encryption and storage systems. We show that a substantial growth of the key length can be achieved by optimized phase and amplitude modulation compared to phase-only encryption. We also provide experimental confirmation of the model results.

  17. Ultrabroadband Electro-Optic Modulator Based on Hybrid Silicon-Polymer Dual Vertical Slot Waveguide

    Directory of Open Access Journals (Sweden)

    Shouyuan Shi

    2011-01-01

    Full Text Available We present a novel hybrid silicon-polymer dual slot waveguide for high speed and ultra-low driving voltage electro-optic (EO modulation. The proposed design utilizes the unique properties of ferroelectric materials such as LiNbO3 to achieve dual RF and optical modes within a low index nanoslot. The tight mode concentration and overlap in the slot allow the infiltrated organic EO polymers to experience enhanced nonlinear interaction with the applied electric field. Half-wavelength voltage-length product and electro-optic response are rigorously simulated to characterize the proposed design, which reveals ultrabroadband operation, up to 250 GHz, and subvolt driving voltage for a 1 cm long modulator.

  18. Secured Optical Communications Using Quantum Entangled Two-Photon Transparency Modulation

    Science.gov (United States)

    Kojima, Jun (Inventor); Nguyen, Quang-Viet (Inventor); Lekki, John (Inventor)

    2015-01-01

    A system and method is disclosed wherein optical signals are coded in a transmitter by tuning or modulating the interbeam delay time (which modulates the fourth-order coherence) between pairs of entangled photons. The photon pairs are either absorbed or not absorbed (transparent) by an atomic or molecular fluorescer in a receiver, depending on the inter-beam delay that is introduced in the entangled photon pairs. Upon the absorption, corresponding fluorescent optical emissions follow at a certain wavelength, which are then detected by a photon detector. The advantage of the disclosed system is that it eliminates a need of a coincidence counter to realize the entanglement-based secure optical communications because the absorber acts as a coincidence counter for entangled photon pairs.

  19. Nonlinear optical microscopy improvement by focal-point axial modulation

    Science.gov (United States)

    Dashtabi, Mahdi Mozdoor; Massudi, Reza

    2016-05-01

    Among the most important challenges of microscopy-even more important than the resolution enhancement, especially in biological and neuroscience applications-is noninvasive and label-free imaging deeper into live scattering samples. However, the fundamental limitation on imaging depth is the signal-to-background ratio in scattering biological tissues. Here, using a vibrating microscope objective in conjunction with a lock-in amplifier, we demonstrate the background cancellation in imaging the samples surrounded by turbid and scattering media, which leads to more clear images deeper into the samples. Furthermore, this technique offers the localization and resolution enhancement as well as resolves ambiguities in signal interpretation, using a single-color laser. This technique is applicable to most nonlinear as well as some linear point-scanning optical microscopies.

  20. Nuclear Technology. Course 27: Metrology. Module 27-4, Angle Measurement Instruments, Optical Projections and Surface Texture Gages.

    Science.gov (United States)

    Selleck, Ben; Espy, John

    This fourth in a series of eight modules for a course titled Metrology describes the universal bevel protractor and the sine bar, the engineering microscope and optical projector, and several types of surface texture gages. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3)…

  1. Simplified architecture for photonic analog-to-digital conversion, utilizing an array of optical modulators

    Science.gov (United States)

    Gevorgyan, Hayk; Khilo, Anatol

    2016-03-01

    In this work a novel photonic sampled and electronically quantized analog-to-digital converter (ADC) system is introduced. High overall sampling rate and relaxed analog bandwidth requirements for photodetectors and electronic quantizers are attained by multichannel architecture. The proposed scheme, with a dedicated electro-optic modulator for each of the channels, is much simpler and has a perspective to outreach the performance of a similar time- wavelength demultiplexed photonic ADC. Absolute optical power isolation between the channels completely eliminates the issue of channel crosstalk, resulting in increased power efficiency of the system. Owing to small number of wavelength demultiplexers less wavelength alignment is required, which reduces the complexity of both photonic and electronic subsystems. Due to the significance of having compact, on-chip photonic ADCs, the analysis of integration of proposed system on a silicon platform is performed. The availability of high performance devices in various Si platforms, such as low loss Si waveguides, microring resonator filters, modulators, photodetectors, necessary for building the system, proves that the photonic ADC is well suited for integration on a silicon chip. For integrated version of proposed architecture Si microring resonator modulators are suitable. They are compact, and can have shorter total length of diode phase shifters as compared to Mach-Zehnder modulators, used in time-wavelength demultiplexed photonic ADCs. To achieve large modulation depth and lower nonlinear distortions, the choice of optimum optical bandwidth of microring modulator is analyzed. Finally, the nonlinearity analysis of ring modulators is performed and the influence of nonlinearities on the ADC performance is discussed.

  2. Simple and Universal Current Modulator Circuit for Indoor Mobile Free-Space-Optical Communications Testing

    Directory of Open Access Journals (Sweden)

    Stanislav Hejduk

    2014-01-01

    Full Text Available The use of LED for illumination and communication together is more and more interesting with the increasing deployment of LEDs to our homes and industrial buildings. Modulation of this kind of light sources is difficult because of high voltage and current demands. Since the LED configurations and values of current and voltage are different, our universal modulator has to be able to operate even under these circumstances. This paper proposes simple and universal current modulator for LED lighting modulation for frequencies around 1MHz. Main objective is to allow initial testing of different types of High Power LEDs and different photodetector configurations and circuits in diffusive based Free-Space-Optical networks. In the experimental part we also compare results for some different types of LED light sources.

  3. Assessment of absolute added correlative coding in optical intensity modulation and direct detection channels

    Science.gov (United States)

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

    2016-06-01

    The performance of absolute added correlative coding (AACC) modulation format with direct detection has been numerically and analytically reported, targeting metro data center interconnects. Hereby, the focus lies on the performance of the bit error rate, noise contributions, spectral efficiency, and chromatic dispersion tolerance. The signal space model of AACC, where the average electrical and optical power expressions are derived for the first time, is also delineated. The proposed modulation format was also compared to other well-known signaling, such as on-off-keying (OOK) and four-level pulse-amplitude modulation, at the same bit rate in a directly modulated vertical-cavity surface-emitting laser-based transmission system. The comparison results show a clear advantage of AACC in achieving longer fiber delivery distance due to the higher dispersion tolerance.

  4. 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...

  5. A Novel Technique of Measuring SOA Differential Carrier Lifetime and a -Factor Using SOA Optical Modulation Response

    Institute of Scientific and Technical Information of China (English)

    Ki-Hyuk Lee; Woo-Young Choi

    2003-01-01

    We demonstrate a new technique of measuring differential carrier lifetime and linewidth enhancement factor in a semiconductor optical amplifier. In our method, the optical responses and fiber transfer functions of a self-gain modulated SOA are measured and, from these, values of carrier lifetimes and linewidth enhancement factors are determined for various SOA input optical powers.

  6. The dressed atom as binary phase modulator: towards attojoule/edge optical phase-shift keying

    CERN Document Server

    Kerckhoff, Joseph; Pavlichin, Dmitri S; Mabuchi, Hideo

    2010-01-01

    Nanophotonic technologies offer great promise for ultra-low power optical signal processing, but relatively few nonlinear-optical phenomena have yet been explored as bases for robust digital modulation/switching~\\cite{Yang07,Fara08,Liu10,Noza10}. Here we show that a single two-level system (TLS) coupled strongly to an optical resonator can impart binary phase modulation on a saturating probe beam. Our experiment relies on spontaneous emission to induce occasional transitions between positive and negative phase shifts---with each such edge corresponding to a dissipated energy of just one photon ($\\approx 0.23$ aJ)---but an optical control beam could be used to trigger additional phase switching at signalling rates above this background. Although our ability to demonstrate controlled switching in our atom-based experiment is limited, we discuss prospects for exploiting analogous physics in a nanophotonic device incorporating a quantum dot as the TLS to realize deterministic binary phase modulation with control ...

  7. Exploiting total internal reflection geometry for efficient optical modulation of terahertz light

    Science.gov (United States)

    Liu, Xudong; Parrott, Edward P. J.; Ung, Benjamin S.-Y.; Pickwell-MacPherson, Emma

    2016-10-01

    Efficient methods to modulate terahertz (THz) light are essential for realizing rapid THz imaging and communication applications. Here we report a novel THz modulator which utilizes the evanescent wave in a total internal reflection setup coupled with a conductive interface to enhance the attenuation efficiency of THz light. This approach makes it possible to achieve close to 100% modulation with a small interface conductivity of 12 mS. The frequency dependence of this technique is linked to the optical properties of the materials: a material with close to frequency independent conductivity that is also controllable will result in an achromatic modulation response, and the device performance can be optimized further by tuning the internal reflection angle. In this work, we focus on applying the technique in the terahertz frequency range. Using an LED array with a pump intensity of 475 mW/cm2 to produce carriers in a silicon wafer, we have achieved a modulation depth of up to 99.9% in a broad frequency range of 0.1 THz-0.8 THz. The required pumping power for the generation of the required free carriers is low because the sheet conductivity needed is far less than required for traditional transmission techniques. Consequently, the device can be modulated by an LED making it a very practical, low cost, and scalable solution for THz modulation.

  8. Adaptive Light Modulation for Improved Resolution and Efficiency in All-Optical Pulse-Echo Ultrasound.

    Science.gov (United States)

    Alles, Erwin J; Colchester, Richard J; Desjardins, Adrien E

    2016-01-01

    In biomedical all-optical pulse-echo ultrasound systems, ultrasound is generated with the photoacoustic effect by illuminating an optically absorbing structure with a temporally modulated light source. Nanosecond range laser pulses are typically used, which can yield bandwidths exceeding 100 MHz. However, acoustical attenuation within tissue or nonuniformities in the detector or source power spectra result in energy loss at the affected frequencies and in a reduced overall system efficiency. In this work, a laser diode is used to generate linear and nonlinear chirp optical modulations that are extended to microsecond time scales, with bandwidths constrained to the system sensitivity. Compared to those obtained using a 2-ns pulsed laser, pulse-echo images of a phantom obtained using linear chirp excitation exhibit similar axial resolution (99 versus 92 μm, respectively) and signal-to-noise ratios (SNRs) (10.3 versus 9.6 dB). In addition, the axial point spread function (PSF) exhibits lower sidelobe levels in the case of chirp modulation. Using nonlinear (time-stretched) chirp excitations, where the nonlinearity is computed from measurements of the spectral sensitivity of the system, the power spectrum of the imaging system was flattened and its bandwidth broadened. Consequently, the PSF has a narrower axial extent and still lower sidelobe levels. Pulse-echo images acquired with time-stretched chirps as optical modulation have higher axial resolution (64 μm) than those obtained with linear chirps, at the expense of a lower SNR (6.8 dB). Using a linear or time-stretched chirp, the conversion efficiency from optical power to acoustical pressure improved by a factor of 70 or 61, respectively, compared to that obtained with pulsed excitation.

  9. Direct-detection optical communication with color coded pulse position modulation signaling

    Science.gov (United States)

    Davidson, F.

    1985-01-01

    The performance characteristics of a direct-detection optical communication system which is based on a laser transmitter which produces single light pulses at selected nonoverlapping optical center frequencies are discussed. The signal format, called color coded pulse position modulation (CCPPM), uses more of the total available response bandwidth characteristics of the photodetector than does ordinary PPM signaling. The advantages of CCPPM signaling are obtained at the expense of an increased optical bandwidth of the transmitted signal and a more complicated transmitter and receiver structure. When the signal format is used in conjunction with block length Reed-Solomon codes, high data rates and reliable high-speed optical communications under conditions of optimal energy efficiency are obtained.

  10. Imaging system of wavelet optics described by the Gaussian linear frequency-modulated complex wavelet

    Science.gov (United States)

    Tan, Liying; Ma, Jing; Wang, Guangming

    2005-12-01

    The image formation and the point-spread function of an optical system are analyzed by use of the wavelet basis function. The image described by a wavelet is no longer an indivisible whole image. It is, rather, a complex image consisting of many wavelet subimages, which come from the changes of different parameters (scale) a and c, and parameters b and d show the positions of wavelet subimages under different scales. A Gaussian frequency-modulated complex-valued wavelet function is introduced to express the point-spread function of an optical system and used to describe the image formation. The analysis, in allusion to the situation of illumination with a monochromatic plain light wave, shows that using the theory of wavelet optics to describe the image formation of an optical system is feasible.

  11. James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (OTIS) Status

    Science.gov (United States)

    Feinberg, Lee; Voyton, Mark; Lander, Julie; Keski-Kuha, Ritva; Matthews, Gary

    2016-01-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated ScienceInstrument Module (ISIM)are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirrorcenter of curvatureoptical tests, electrical and operational tests, acoustics and vibration testing at the Goddard SpaceFlight Center beforebeing shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparationfor the cryogenicoptical testing, the JWST project has built a Pathfinder telescope and has completed two OpticalGround SystemEquipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize opticaltest results todate and status the final Pathfinder test and the OTIS integration and environmental test preparations

  12. Two-photon microscopy with diffractive optical elements and spatial light modulators

    Directory of Open Access Journals (Sweden)

    Brendon O Watson

    2010-09-01

    Full Text Available Two-photon microscopy is often performed at slow frame rates, due to the need to serially scan all points in a field of view with a single laser beam. To overcome this problem, we have developed two optical methods that split and multiplex a laser beam across the sample. In the first method a diffractive optical element (DOE generates a fixed number of beamlets that are scanned in parallel, resulting in a corresponding increase in speed, or in signal-to-noise ratio, in time-lapse measurements. The second method uses a computer-controlled spatial light modulator (SLM, to generate any arbitrary spatio-temporal light pattern. With an SLM one can image or photostimulate any predefined region of the image, such as neurons or dendritic spines. In addition, SLMs can be used to mimic a large number of optical transfer functions, including light path corrections or as adaptive optical devices.

  13. Method to Enhance the Operation of an Optical Inspection Instrument Using Spatial Light Modulators

    Science.gov (United States)

    Trolinger, James; Lal, Amit; Jo, Joshua; Kupiec, Stephen

    2012-01-01

    For many aspheric and freeform optical components, existing interferometric solutions require a custom computer-generated hologram (CGH) to characterize the part. The overall objective of this research is to develop hardware and a procedure to produce a combined, dynamic, Hartmann/ Digital Holographic interferometry inspection system for a wide range of advanced optical components, including aspheric and freeform optics. This new instrument would have greater versatility and dynamic range than currently available measurement systems. The method uses a spatial light modulator to pre-condition wavefronts for imaging, interferometry, and data processing to improve the resolution and versatility of an optical inspection instrument. Existing interferometers and Hartmann inspection systems have either too small a dynamic range or insufficient resolution to characterize conveniently unusual optical surfaces like aspherical and freeform optics. For interferometers, a specially produced, computer-generated holographic optical element is needed to transform the wavefront to within the range of the interferometer. A new hybrid wavefront sensor employs newly available spatial light modulators (SLMs) as programmable holographic optical elements (HOEs). The HOE is programmed to enable the same instrument to inspect an optical element in stages, first by a Hartmann measurement, which has a very large dynamic range but less resolution. The first measurement provides the information required to precondition a reference wave that avails the measurement process to the more precise phase shifting interferometry. The SLM preconditions a wavefront before it is used to inspect an optical component. This adds important features to an optical inspection system, enabling not just wavefront conditioning for null testing and dynamic range extension, but also the creation of hybrid measurement procedures. This, for example, allows the combination of dynamic digital holography and Hartmann

  14. Dynamic complex optical fields for optical manipulation, 3D microscopy, and photostimulation of neurotransmitters

    Science.gov (United States)

    Daria, Vincent R.; Stricker, Christian; Bekkers, John; Redman, Steve; Bachor, Hans

    2010-08-01

    We demonstrate a multi-functional system capable of multiple-site two-photon excitation of photo-sensitive compounds as well as transfer of optical mechanical properties on an array of mesoscopic particles. We use holographic projection of a single Ti:Sapphire laser operating in femtosecond pulse mode to show that the projected three-dimensional light patterns have sufficient spatiotemporal photon density for multi-site two-photon excitation of biological fluorescent markers and caged neurotransmitters. Using the same laser operating in continuous-wave mode, we can use the same light patterns for non-invasive transfer of both linear and orbital angular momentum on a variety of mesoscopic particles. The system also incorporates high-speed scanning using acousto-optic modulators to rapidly render 3D images of neuron samples via two-photon microscopy.

  15. Performance evaluation of intensity modulated optical OFDM system with digital baseband distortion.

    Science.gov (United States)

    Vanin, Evgeny

    2011-02-28

    Bit-Error-Ratio (BER) of intensity modulated optical orthogonal frequency division multiplexing (OFDM) system is analytically evaluated accounting for nonlinear digital baseband distortion in the transmitter and additive noise in the photo receiver. The nonlinear distortion that is caused by signal clipping and quantization is taken into consideration. The signal clipping helps to overcome the system performance limitation related to high peak-to-average power ratio (PAPR) of the OFDM signal and to minimize the value of optical power that is required for achieving specified BER. The signal quantization due to a limited bit resolution of the digital to analog converter (DAC) causes an optical power penalty in the case when the bit resolution is too low. By introducing an effective signal to noise ratio (SNR) the optimum signal clipping ratio, system BER and required optical power at the input to the receiver is evaluated for the OFDM system with multi-level quadrature amplitude modulation (QAM) applied to the optical signal subcarriers. Minimum required DAC bit resolution versus the size of QAM constellation is identified. It is demonstrated that the bit resolution of 7 and higher causes negligibly small optical power penalty at the system BER=10⁻³ when 256-QAM and a constellation of lower size is applied. The performance of the optical OFDM system is compared to the performance of the multi-level amplitude-shift keying (M-ASK) system for the same number of information bits transmitted per signal sample. It is demonstrated that in the case of the matched receiver the M-ASK system outperforms OFDM and requires 3-3.5 dB less of optical power at BER=10⁻³ when 1-4 data bits are transmitted per signal sample. PMID:21369258

  16. Optical power supply unit utilizing high power laser diode module developed for fiber laser pumping

    Science.gov (United States)

    Sakamoto, Akira; Kiyoyama, Wataru; Yamauchi, Ryozo

    2014-05-01

    High power laser diode developed for fiber laser pumping is evaluated as a light source for an optical power supply unit. The output power of the newly developed laser diode module exceeds 15 W with 105 μm core fiber. It is estimated that more than 1600 mW power supply can be achieved with the single emitter laser diode module and a polycrystalline silicon cell over 1 km away from the light source. This unit can be used for sensor nodes in the fiber sensor network.

  17. 12.5 Gb/s carrier-injection silicon Mach-Zehnder optical modulator

    Institute of Scientific and Technical Information of China (English)

    Chen Hongtao; Ding Jianfeng; Yang Lin

    2012-01-01

    We demonstrate a 12.5 Gb/s carrier-injection silicon Mach-Zehnder optical modulator.Under a nonreturn-zero (NRZ) pre-emphasized electrical drive signal with voltage swing of 6.3 V and forward bias of 0.7 V,the eye is clearly opened with an extinction ratio of 8.4 dB.The device exhibits high modulation efficiency,with a figure of merit VπL of 0.036 V.mm.

  18. Electronic heterodyne recording and processing of optical holograms using phase modulated reference waves

    Science.gov (United States)

    Decker, A. J.; Pao, Y.-H.; Claspy, P. C.

    1978-01-01

    The use of a phase-modulated reference wave for the electronic heterodyne recording and processing of a hologram is described. Heterodyne recording is used to eliminate the self-interference terms of a hologram and to create a Leith-Upatnieks hologram with coaxial object and reference waves. Phase modulation is also shown to be the foundation of a multiple-view hologram system. When combined with hologram scale transformations, heterodyne recording is the key to general optical processing. Spatial filtering is treated as an example.

  19. Analysis of compressive sensing with optical mixing using a spatial light modulator.

    Science.gov (United States)

    Zhu, Zhijing; Chi, Hao; Zheng, Shilie; Jin, Tao; Jin, Xiaofeng; Zhang, Xianmin

    2015-03-10

    Compressive sensing (CS) in a photonic link has a high potential for acquisition of wideband sparse signals. In CS it is necessary to mix the input sparse signal with a pseudorandom sequence prior to subsampling. A pulse shaper with a spatial light modulator (SLM) can be used in photonic CS as an optical mixer to improve the speed of mixing. In this approach, the sparse signal is modulated on a chirped optical pulse and the pseudorandom sequence is recorded on the SLM within the pulse shaper. The optical mixing in the frequency domain is realized based on the principle of frequency-to-time mapping. In this paper, we investigate the performance and limitations of photonic CS with an SLM in detail. A theoretical model to describe optical mixing based on frequency-to-time mapping is presented. We point out that there is an upper limit on the length of the pseudorandom sequence recorded on the SLM that can be mixed with the sparse signal due to the condition of the far-field approximation of the frequency-to-time mapping. Since the length of the pseudorandom sequence is one of the major factors that affect the signal recovery performance in CS, this limitation should be fully considered in the system design of the CS with optical mixing in the frequency domain. We present numerical and experimental results to verify the theoretical findings. Discussion on the performance improvement is also presented.

  20. Implementation of pulse interval modulation based on dualmapping technique for optical wireless communications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tie-ying; WANG Hong-xing; HU Hao; CONG Pei-sheng

    2009-01-01

    Aiming at implementing the digital pulse interval modulation (DPIM) for optical wireless communications (OWC), a dual-mapping technique is presented. The scheme of DPIM train based upon the dual-mapping technique is given. Its slot error rate is derived for the avalanche photonic diode (APD) receiver model, and is compared with that of classical DPIM. Simulation results show that the dual-mapping DPIM (D-DPIM), which has a fixed slot length, only has marginally inferior error performance, but can solve waiting slots or buffer overflowing in comparison with DPIM. Hence, it is suitable for the optical wireless communication systems.

  1. The optical modules of the phase-2 of the NEMO project

    International Nuclear Information System (INIS)

    A 13-inch Optical Module (OM) containing a large-area (10-inch) photomultiplier was designed as part of Phase-2 of the NEMO project. An intense R and D activity on the photomultipliers, the voltage supply boards, the optical coupling as well as the study of the influences of the Earth's magnetic field has driven the choice of each single component of the OM. Following a well-established production procedure, 32 OMs were assembled and their functionality tested. The design, the testing and the production phases are thoroughly described in this paper

  2. Digital Square-Wave Frequency Modulated Microwave Sources for a Miniature Optically Pumped Cesium Beam Clock

    Institute of Scientific and Technical Information of China (English)

    CHEN Jingbiao; ZHU Chengjin; LIU Ge; WANG Fengzhi; WANG Yiqiu; YANG Donghai

    2001-01-01

    Three different digital frequencymodulated microwave sources have been designed andapplied to our miniature optically pumped cesiumbeam clock.The main features and their influenceon clock accuracy have been experimentally tested.Itis proved that a digital square-wave frequency modu-lated microwave source using a microprocessor con-trolled direct-digital frequency synthesizer (DDFS)for our miniature optically pumped cesium beamclock works well,the frequency short term stability2 × 10 11/x r and the long term stability 3.5 x 10-13 forone day sample time have been obtained.

  3. The optical modules of the phase-2 of the NEMO project

    Science.gov (United States)

    Aiello, S.; Leonora, E.; Ameli, F.; Anghinolfi, M.; Anzalone, A.; Barbarino, G.; Barbarito, E.; Barbato, F.; Bersani, A.; Beverini, N.; Biagi, S.; Bonori, M.; Bouhadef, B.; Bozza, C.; Cacopardo, G.; Capone, A.; Caruso, F.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Cordelli, M.; Costa, M.; D'Amico, A.; De Asmundis, R.; De Bonis, G.; De Rosa, G.; De Vita, R.; Distefano, C.; Fermani, P.; Flaminio, V.; Fusco, L. A.; Garufi, F.; Giordano, V.; Giovanetti, G.; Grella, G.; Grimaldi, A.; Habel, R.; Imbesi, M.; Kulikovsky, V.; Lattuada, D.; Leotta, G.; Lonardo, A.; Longhitano, F.; Lo Presti, D.; Maccioni, E.; Margiotta, A.; Marinelli, A.; Martini, A.; Masullo, R.; Maugeri, F.; Migliozzi, P.; Migneco, E.; Minutoli, S.; Miraglia, A.; Mollo, C.; Mongelli, M.; Morganti, M.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Papaleo, R.; Pappalardo, V.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Pugliatti, C.; Pulvirenti, S.; Raffaelli, F.; Raia, G.; Randazzo, N.; Riccobene, G.; Rovelli, A.; Russo, A.; Russo, G. V.; Sapienza, P.; Sciliberto, D.; Sedita, M.; Sgura, I.; Shirokov, E.; Simeone, F.; Sipala, V.; Sollima, C.; Spina, M.; Spurio, M.; Stefani, F.; Taiuti, M.; Terreni, G.; Trasatti, L.; Trovato, A.; Vicini, P.; Viola, S.; Vivolo, D.

    2013-07-01

    A 13-inch Optical Module (OM) containing a large-area (10-inch) photomultiplier was designed as part of Phase-2 of the NEMO project. An intense R&D activity on the photomultipliers, the voltage supply boards, the optical coupling as well as the study of the influences of the Earth's magnetic field has driven the choice of each single component of the OM. Following a well-established production procedure, 32 OMs were assembled and their functionality tested. The design, the testing and the production phases are thoroughly described in this paper.

  4. Speckle decorrelation in Ultrasound-modulated optical tomography made by heterodyne holography

    CERN Document Server

    Gross, M

    2016-01-01

    Ultrasound-modulated optical tomography (UOT) is a technique that images optical contrast deep inside scattering media. Heterodyne holography is a promising tool able to detect the UOT tagged photons with high efficiency. In this work, we describe theoretically the detection of the tagged photon in heterodyne holography based UOT, show how to filter the untagged photon discuss, and discuss the effect of speckle decorrelation. We show that optimal detection sensitivity can obtain, if the frame exposure time is of the order of the decorrelation time.

  5. Sound field reconstruction based on the acousto-optic effect

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Barrera Figueroa, Salvador; Jacobsen, Finn

    2011-01-01

    Acoustic measurements are usually carried out with transducers that interact mechanically with the sound field under investigation. The goal of this work is to employ a completely different measurement principle, the determination of sound pressure based on the interaction between sound and light...

  6. Infrared fiber coupled acousto-optic tunable filter spectrometer

    Science.gov (United States)

    Levin, K. H.; Kindler, E.; Ko, T.; Lee, F.; Tran, D. C.; Tapphorn, R. M.

    A spectrometer design is introduced which combines an acoustooptic tunable filter (AOTF) and IR-transmitting flouride-glass fibers. The AOTF crystal is fabricated from TeO2 and permits random access to any wavelength in less than 50 microseconds, and the resulting spectrometer is tested for the remote analysis of gases and hydrocarbons. The AOTF spectrometer, when operated with a high-speed frequency synthesizer and optimized algorithms, permits accurate high-speed spectroscopy in the mid-IR spectral region.

  7. Macroscopic acousto-mechanical analogy of a microbubble

    CERN Document Server

    Chaline, Jennifer; Mehrem, Ahmed; Bouakaz, Ayache; Santos, Serge Dos; Sánchez-Morcillo, Víctor J

    2015-01-01

    Microbubbles, either in the form of free gas bubbles surrounded by a fluid or encapsulated bubbles used currently as contrast agents for medical echography, exhibit complex dynamics under specific acoustic excitations. Nonetheless, considering their micron size and the complexity of their interaction phenomenon with ultrasound waves, expensive and complex experiments and/or simulations are required for their analysis. The behavior of a microbubble along its equator can be linked to a system of coupled oscillators. In this study, the oscillatory behavior of a microbubble has been investigated through an acousto-mechanical analogy based on a ring-shaped chain of coupled pendula. Observation of parametric vibration modes of the pendula ring excited at frequencies between $1$ and $5$ Hz is presented. Simulations have been carried out and show mode mixing phenomena. The relevance of the analogy between a microbubble and the macroscopic acousto-mechanical setup is discussed and suggested as an alternative way to in...

  8. Semiconductor optical amplifier direct modulation with double-stage birefringent fiber loop

    Science.gov (United States)

    Engel, Thomas; Rizou, Zoe V.; Zoiros, Kyriakos E.; Morel, Pascal

    2016-06-01

    The feasibility of cascading two birefringent fiber loops (BFLs) for directly modulating a conventional semiconductor optical amplifier (SOA) at a faster data rate than that being possible by its limited electrical bandwidth is demonstrated for the first time. The experimental results reveal the improvements in the quality characteristics of the encoded signal compared to those achieved with a single-stage BFL. The observed trends are complemented by numerical simulations, which allow to investigate the impact of the double-stage BFL detuning and specify how this critical parameter must be selected for enhanced performance. Provided that it is properly tailored, the proposed optical notch filtering scheme efficiently compensates for the pattern-dependent SOA response and enables this element to be employed as intensity modulator with improved performance at enhanced data speeds.

  9. Detection and processing of phase modulated optical signals at 40 Gbit/s and beyond

    DEFF Research Database (Denmark)

    Geng, Yan

    This thesis addresses demodulation in direct detection systems and signal processing of high speed phase modulated signals in future all-optical wavelength division multiplexing (WDM) communication systems where differential phase shift keying (DPSK) or differential quadrature phase shift keying...... at the receiver side. This is typically implemented in a one bit delay Mach-Zehnder interferometer (MZI). Two alternative ways of performing phase-to-intensity modulation conversion are presented. Successful demodulation of DPSK signals up to 40 Gbit/s is demonstrated using the proposed two devices. Optical...... km post-compensated non-zero dispersion shifted fiber (NZDSF) span. Using orthogonal labeling, an amplitude shift keying (ASK)/DPSK labeled signal using 40 Gbit/s return-to-zero (RZ) payload and 2.5 Gbit/s DPSK label, is generated. WDM transmission and label swapping are demonstrated...

  10. Design and mass production of the optical modules for KM3NeT-Italia project

    Science.gov (United States)

    Leonora, Emanuele; Aiello, Sebastiano; Giordano, Valentina

    2016-04-01

    The KM3NeT European project aims at constructing a km3 underwater neutrino telescope in the depths of the Mediterranean Sea. The first phase that is under construction will comprise eight tower-like detection structures (KM3NeT-Italia), which will form the internal core of a km3-scale detector. The detection element of KM3NeT-Italia, the optical module, is made of a 13-inch pressure-resistant glass-vessel that contains a single 10-inch photomultiplier and the relative electronics. The design of the whole optical module, the main results obtained from the massive photomultipliers measurements, and the foremost phases of the mass production procedure performed at the production site of Catania are also presented.

  11. Energy modulation of nonrelativistic electrons in an optical near field on a metal microslit

    Science.gov (United States)

    Ishikawa, R.; Bae, J.; Mizuno, K.

    2001-04-01

    Energy modulation of nonrelativistic electrons with a laser beam using a metal microslit as an interaction circuit has been investigated. An optical near field is induced in the proximity of the microslit by illumination of the laser beam. The electrons passing close to the slit are accelerated or decelerated by an evanescent wave contained in the near field whose phase velocity is equal to the velocity of the electrons. The electron-evanescent wave interaction in the microslit has been analyzed theoretically and experimentally. The theory has predicted that electron energy can be modulated at optical frequencies. Experiments performed in the infrared region have verified theoretical predictions. The electron-energy changes of more than ±5 eV with a 10 kW CO2 laser pulse at the wavelength of 10.6 μm has been successfully observed for an electron beam with an energy of less than 80 keV.

  12. Progress on the WOM (Wavelength-shifting optical module) development for IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Hebecker, Dustin [DESY Zeuthen (Germany)

    2015-07-01

    For ongoing studies for the extension of the IceCube neutrino observatory to low energies (PINGU) and high energies the noise rate of the optical modules should be decreased and the effective area increased in order to improve energy resolution and overall sensitivity. The WOM (Wavelength-shifting optical module) targets this points by expanding the capture area while decreasing the size of the PMT and thus decreasing the noise rate. Photons are first captured in an organic wavelength-shifting material (WLS) that is coated on light guiding material to guide the light to two smaller PMTs. This allows to achieve a very large collection area and reduces the noise to the order of 10 Hz in comparison to 600-800 Hz (IceCube DOM). The progress on the necessary WLS paint development and substrate selection will be presented. Also a brief status / outlook on the prototype assembly will be given.

  13. Design and mass production of the optical modules for KM3NeT-Italia project

    Directory of Open Access Journals (Sweden)

    Leonora Emanuele

    2016-01-01

    Full Text Available The KM3NeT European project aims at constructing a km3 underwater neutrino telescope in the depths of the Mediterranean Sea. The first phase that is under construction will comprise eight tower-like detection structures (KM3NeT-Italia, which will form the internal core of a km3-scale detector. The detection element of KM3NeT-Italia, the optical module, is made of a 13-inch pressure-resistant glass-vessel that contains a single 10-inch photomultiplier and the relative electronics. The design of the whole optical module, the main results obtained from the massive photomultipliers measurements, and the foremost phases of the mass production procedure performed at the production site of Catania are also presented.

  14. 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.

  15. Direct Measurement of Local Chromatin Fluidity Using Optical Trap Modulation Force Spectroscopy

    OpenAIRE

    Roopa, T.; Shivashankar, G. V.

    2006-01-01

    Chromatin assembly is condensed by histone tail-tail interactions and other nuclear proteins into a highly compact structure. Using an optical trap modulation force spectroscopy, we probe the effect of tail interactions on local chromatin fluidity. Chromatin fibers, purified from mammalian cells, are tethered between a microscope coverslip and a glass micropipette. Mechanical unzipping of tail interactions, using the micropipette, lead to the enhancement of local fluidity. This is measured us...

  16. Theory of Optical Rectification Effect in Metallic Thin Film with Periodic Modulation

    CERN Document Server

    Hiroyuki, Kurosawa; Nakayama, Kazuyuki

    2014-01-01

    We carried out theoretical and numerical investigation of optical rectification (OR) effect in metallic structure with periodic modulation. A new formulation of the OR effect is presented and the generation mechanism of OR effect, which was a controversy issue in previous works, is clarified. We revealed that OR effect is strongly enhanced by the combination of spatial variation of metallic structure and local electric field enhancement. Our theory was numerically evaluated and showed fairly well agreement with experiment.

  17. Optical phase modulator utilizing a transparent piezofilm for use with the extrinsic fiber interferometer

    Science.gov (United States)

    Sudarshanam, V. S.; Claus, Richard O.

    1993-03-01

    A piezoelectnc polyvinylidene flouride (PVF2) film with transparent indium tin oxide electrode metallization is placed directly in the path of a single mode fiber output, to form an extrinsic optical interferometer. This device can be used concurrently with another extrinsic inteferometer on a fiber directional coupler to generate a carrier phase modulation on which the signal phase shift is superimposed. Experimental results of the induced phase shifting coefficient are presented for two arrangements of the piezofilm differing in their boundary clamping conditions.

  18. Pixel size and pitch measurements of liquid crystal spatial light modulator by optical diffraction

    Indian Academy of Sciences (India)

    Ravinder Kumar Banyal; B Raghavendra Prasad

    2005-08-01

    We present a simple technique for the determination of pixel size and pitch of liquid crystal (LC) based spatial light modulator (SLM). The proposed method is based on optical diffraction from pixelated LC panel that has been modeled as a two-dimensional array of rectangular apertures. A novel yet simple, two-plane measurement technique is implemented to circumvent the difficulty in absolute distance measurement. Experimental results are presented for electrically addressed twisted nematic LC-SLM removed from the display projector.

  19. Frequency translation of light waves by propagation around an optical ring circuit containing a frequency shifter: I. Experiment.

    Science.gov (United States)

    Shimizu, K; Horiguchi, T; Koyamada, Y

    1993-11-20

    A technique for the external frequency translation of light waves is reported. The technique permits the stepwise sweeping of an optical frequency over a wide range with high linearity with respect to time. The frequency translator is composed of an optical pulse modulator and an optical ring circuit containing an acousto-optic frequency shifter and an optical amplifier. The pulse launched into the ring circuit undergoes a constant frequency shift for each circulation around the circuit and the frequency can be translated to a considerable degree from that of the original input pulse. We report a stepwise frequency translation over approximately 68 GHz for a 1.5-µm light wave with a strictly constant frequency-sweep rate and an approximately constant intensity.

  20. Synthesis and optical characterization of LiKB4O7, Li2B6O10, and LiCsB6O10 glasses

    Energy Technology Data Exchange (ETDEWEB)

    Adamiv, V.; Teslyuk, I.; Dyachok, Ya.; Romanyuk, G.; Krupych, O.; Mys, O.; Martynyuk-Lototska, I.; Burak, Ya.; Vlokh, R.

    2010-10-01

    In the current work we report on the synthesis of LiKB4O7, Li2B6O10, and LiCsB6O10 borate glasses. The results for their piezo-optic, acousto-optic, acoustic, elastic, refractive, optical transmission, and optical resistance properties are also presented. It is shown that some of these glasses represent efficient acousto-optic materials that are transparent down to the vacuum ultraviolet range and highly resistant to laser radiation.

  1. Synthesis and optical characterization of LiKB4O7, Li2B6O10, and LiCsB6O10 glasses.

    Science.gov (United States)

    Adamiv, V; Teslyuk, I; Dyachok, Ya; Romanyuk, G; Krupych, O; Mys, O; Martynyuk-Lototska, I; Burak, Ya; Vlokh, R

    2010-10-01

    In the current work we report on the synthesis of LiKB(4)O(7), Li(2)B(6)O(10), and LiCsB(6)O(10) borate glasses. The results for their piezo-optic, acousto-optic, acoustic, elastic, refractive, optical transmission, and optical resistance properties are also presented. It is shown that some of these glasses represent efficient acousto-optic materials that are transparent down to the vacuum ultraviolet range and highly resistant to laser radiation.

  2. Characterization benches for neutrino telescope Optical Modules at the APC laboratory

    Science.gov (United States)

    Avgitas, Theodore; Creusot, Alexandre; Kouchner, Antoine

    2016-04-01

    As has been demonstrated by the first generation of neutrino telescopes Antares and IceCube, precise knowledge of the photon detection efficiency of optical modules is of fundamental importance for the understanding of the instrument and accurate event reconstruction. Dedicated test benches have been developed to measure all related quantities for the Digital Optical Modules of the KM3NeT neutrino telescope being currently deployed in the Mediterranean sea. The first bench is a black box with robotic arms equipped with a calibrated single photon source or laser which enable a precise mapping of the detection efficiency at arbitrary incident angles as well as precise measurements of the time delays induced by the photodetection chain. These measurement can be incorporated and compared to full GEANT MonteCarlo simulations of the optical modules. The second bench is a 2 m×2 m ×2 m water tank equipped with muon hodoscopes on top and bottom. It enables to study and measure the angular dependence of the DOM's detection efficiency of the Cherenkov light produced in water by relativistic muons, thus reproducing in situ detection conditions. We describe these two benches and present their first results and status.

  3. Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Feng; Spring, Andrew M. [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Sato, Hiromu [Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke [Nissan Chemical Industries, Ltd., 2-10-1 Tuboi Nishi, Funabashi, Chiba 274-8507 (Japan); Aoki, Isao; Otomo, Akira [National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe 651-2492 (Japan); Yokoyama, Shiyoshi, E-mail: s-yokoyama@cm.kyushu-u.ac.jp [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan)

    2015-09-21

    Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed and fabricated. The waveguide consists of a silicon core with a thickness of 30 nm and a width of 2 μm. The cladding is an EO polymer. Optical mode calculation reveals that 55% of the optical field around the silicon extends into the EO polymer in the TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. The measured half-wave voltage of the MZI with 7 μm spacing and 1.3 cm long electrodes is 4.6 V at 1550 nm. The evaluated EO coefficient is 70 pm/V, which is comparable to that of the bulk EO polymer film. Using ultra-thin silicon is beneficial in order to reduce the side-wall scattering loss, yielding a propagation loss of 4.0 dB/cm. We also investigated a mode converter which couples light from the hybrid EO waveguide into a strip silicon waveguide. The calculation indicates that the coupling loss between these two devices is small enough to exploit the potential fusion of a hybrid EO polymer modulator together with a silicon micro-photonics device.

  4. RF-modulated pulsed fiber optic lidar transmitter for improved underwater imaging and communications

    Science.gov (United States)

    Kimpel, F.; Chen, Y.; Fouron, J.-L.; Akbulut, M.; Engin, D.; Gupta, S.

    2011-03-01

    We present results on the design, development and initial testing of a fiber-optic based RF-modulated lidar transmitter operating at 532nm, for underwater imaging application in littoral waters. The design implementation is based on using state-of-the-art high-speed FPGAs, thereby producing optical waveforms with arbitrary digital-RF-modulated pulse patterns with carrier frequencies >= 3GHz, with a repetition rate of 0.5-1MHz, and with average powers >=5W (at 532nm). Use of RF-modulated bursts above 500MHz, instead of single optical pulse lidar detection, reduces the effect of volumetric backscatter for underwater imaging application, leading to an improved signal-to-noise-ratio (SNR) and contrast, for a given range. Initial underwater target detection tests conducted at Patuxent River Naval Air Station, MD, in a large water-tank facility, validates the advantages of this hybrid-lidar-radar (HLR) approach for improved underwater imaging, over a wide range of turbidity levels and both white and black targets. The compact, robust and power-efficient fiber laser architecture lends very well to lidar sensor integration on unmanned-underwater-vehicle (UUV) platforms. HLR transmitters can also provide similar advantages in active-sensing situations dominated by continuous backscatter, e.g. underwater communications, imaging through smoke and fire environment, rotor-craft landing in degraded visual environment, and pointing-tracking of active-EO sensors through fog.

  5. Time- and space-modulated Raman signals in graphene-based optical cavities

    Science.gov (United States)

    Reserbat-Plantey, Antoine; Klyatskaya, Svetlana; Reita, Valérie; Marty, Laëtitia; Arcizet, Olivier; Ruben, Mario; Bendiab, Nedjma; Bouchiat, Vincent

    2013-11-01

    We present fabrication and optical characterization of micro-cavities made of multilayer graphene (MLG) cantilevers clamped by metallic electrodes and suspended over Si/SiO2 substrates. Graphene cantilevers act as semi-transparent mirrors closing air wedge optical cavities. This simple geometry implements a standing-wave optical resonator along with a mechanical one. Equal thickness interference fringes are observed in both Raman and Rayleigh backscattered signals, with interfringe given by their specific wavelength. Chromatic dispersion within the cavity makes possible the spatial modulation of graphene Raman lines and selective rejection of the silicon background signal. Electrostatic actuation of the multilayer graphene cantilever by a gate voltage tunes the cavity length and induces space and time modulation of the backscattered light, including the Raman lines. We demonstrate the potential of these systems for high-sensitivity Raman measurements of generic molecular species grafted on a multilayer graphene surface. The Raman signal of the molecular layer can be modulated both in time and space in a similar fashion and shows enhancement with respect to a collapsed membrane.

  6. Performance of closed-loop resonant micro-optic gyro with hybrid digital phase modulation

    Science.gov (United States)

    Zhang, Jianjie; Wang, Linglan; Ma, Huilian; Jin, Zhonghe

    2015-07-01

    A double closed-loop resonant micro optic gyro (RMOG) employing a hybrid digital phase modulation technique is demonstrated, showing encouraging progress. In this hybrid modulation scheme, the width of one stair of the stair-like digital serrodyne wave is optimized according to the rise time of the digital-to-analogue converter to obtain the maximum sideband suppression. Based on the optimum parameters of the hybrid modulation scheme, a typical bias stability of 0.05/s in 1 hr is demonstrated in an RMOG with a silica waveguide ring resonator having a ring length of 7.9 cm. This is the best long-term performance which has ever been reported in an RMOG to our knowledge.

  7. Jitter model and signal processing techniques for pulse width modulation optical recording

    Science.gov (United States)

    Liu, Max M.-K.

    1991-01-01

    A jitter model and signal processing techniques are discussed for data recovery in Pulse Width Modulation (PWM) optical recording. In PWM, information is stored through modulating sizes of sequential marks alternating in magnetic polarization or in material structure. Jitter, defined as the deviation from the original mark size in the time domain, will result in error detection if it is excessively large. A new approach is taken in data recovery by first using a high speed counter clock to convert time marks to amplitude marks, and signal processing techniques are used to minimize jitter according to the jitter model. The signal processing techniques include motor speed and intersymbol interference equalization, differential and additive detection, and differential and additive modulation.

  8. Design and optimization of optical modulators based on graphene-on-silicon nitride microring resonators

    CERN Document Server

    Wu, Zeru; Zhang, Tianyou; Shao, Zengkai; Wen, Yuanhui; Xu, Pengfei; Zhang, Yanfeng; Yu, Siyuan

    2016-01-01

    In order to overcome the challenge of obtaining high modulation depth due to weak graphene-light interaction, a graphene-on-silicon nitride (SiNx) microring resonator based on graphene's gate-tunable optical conductivity is proposed and studied. Geometrical parameters of graphene-on-SiNx waveguide are systematically analyzed and optimized, yielding a loss tunability of 0.04 dB/{\\mu}m and an effective index variation of 0.0022. We explicitly study the interaction between graphene and a 40-{\\mu}m-radius microring resonator, where electro-absorptive and electro-refractive modulation are both taken into account. By choosing appropriate graphene coverage and coupling coefficient, a high modulation depth of over 40 dB with large fabrication tolerance is obtained.

  9. All-fiber optical modulator based on no-core fiber and magnetic fluid as cladding

    International Nuclear Information System (INIS)

    An all-fiber optical modulator, which is composed of a piece of no-core fiber spliced between two sections of single-mode fibers and uses magnetic fluid (MF) as the cladding of the no-core fiber section, is proposed and investigated experimentally. Due to the tunable refractive index and absorption coefficient of MF, the output intensity can be modulated by controlling an applied magnetic field. The dependences of the modulator’s temporal response on the working wavelength, the magnetic field strength (H), and the MF’s concentration are investigated experimentally. The results are explained qualitatively by the dynamic response process of MF under the action of a magnetic field. The findings are helpful for optimizing this kind of modulator. (paper)

  10. Fully passive-alignment pluggable compact parallel optical interconnection modules based on a direct-butt-coupling structure for fiber-optic applications

    Science.gov (United States)

    Lim, Kwon-Seob; Park, Hyoung-Jun; Kang, Hyun Seo; Kim, Young Sun; Jang, Jae-Hyung

    2016-02-01

    A low-cost packaging method utilizing a fully passive optical alignment and surface-mounting method is demonstrated for pluggable compact and slim multichannel optical interconnection modules using a VCSEL/PIN-PD chip array. The modules are based on a nonplanar bent right-angle electrical signal path on a silicon platform and direct-butt-optical coupling without a bulky and expensive microlens array. The measured optical direct-butt-coupling efficiencies of each channel without any bulky optics are as high as 33% and 95% for the transmitter and receiver, respectively. Excellent lateral optical alignment tolerance of larger than 60 μm for both the transmitter and receiver module significantly reduces the manufacturing and material costs as well as the packaging time. The clear eye diagrams, extinction ratios higher than 8 dB at 10.3 Gbps for the transmitter module, and receiver sensitivity of better than -13.1 dBm at 10.3 Gbps and a bit error rate of 10-12 for all channels are demonstrated. Considering that the optical output power of the transmitter is greater than 0 dBm, the module has a sufficient power margin of about 13 dB for 10.3 Gbps operations for all channels.

  11. A study on the optical parts for a semiconductor laser module

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jun-Girl; Lee, Dong-Kil; Kim, Yang-Gyu; Lee, Kwang-Hoon; Park, Young-Sik [Korea Photonics Technology Institute, Gwangju (Korea, Republic of); Jang, Kwang-Ho [Hanvit Optoline, Gwangju (Korea, Republic of); Kang, Seung-Goo [COSET, Gwangju (Korea, Republic of)

    2014-11-15

    A semiconductor laser module consists of a LD (laser diode) chip that generates a laser beam, two cylindrical lenses to collimate the laser beam, a high-reflection mirror to produce a large output by collecting the laser beam, a collimator lens to guide the laser beam to an optical fiber and a protection filter to block reflected laser light that might damage the LD chip. The cylindrical lenses used in a semiconductor laser module are defined as FACs (fast axis collimators) and SACs (slow axis collimators) and are attached to the system module to control the shape of the laser beam. The FAC lens and the SAC lens are made of a glass material to protect the lenses from thermal deformation. In addition, they have aspheric shapes to improve optical performances. This paper presents a mold core grinding process for an asymmetrical aspheric lens and a GMP (glass molding press), what can be used to make aspheric cylindrical lenses for use as FACs or SACs, and a protection filter made by using IAD (ion-beam-assisted deposition). Finally, we developed the aspheric cylindrical lenses and the protection filter for a 10-W semiconductor laser module.

  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

    2015-05-01

    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. PMID:25969323

  13. A laboratory module on radiometry, photometry and colorimetry for an undergraduate optics course

    Science.gov (United States)

    Polak, Robert D.

    2014-07-01

    The bachelor's degree in Physics at Loyola University Chicago requires both an upper-division course in Optics as well as a companion Optics Laboratory course. Recently, the laboratory course has undergone dramatic changes. Traditional weekly laboratories have been replaced with three laboratory modules, where students focus on a single topic over several weeks after which the students submit a laboratory report written in the style of a journal article following American Institute of Physics style manual. With this method, students are able to gain a deeper understanding of the specific topic areas of radiometry, photometry and colorimetry, lens design and aberrations, and polarization and interference while using industry-standard equipment and simulation software. In particular, this work will provide the details of the laboratory module on radiometry, photometry and colorimetry where students use a photoradiometer and integrating sphere to characterize the optical properties of an LCD monitor, light bulb and a fiber optic light source calculating properties such as luminous flux, luminous intensity, luminance, CIE color coordinates, NTSC ratio, color temperature and luminous efficacy.

  14. Engineering Optics

    CERN Document Server

    Iizuka, Keigo

    2008-01-01

    Engineering Optics is a book for students who want to apply their knowledge of optics to engineering problems, as well as for engineering students who want to acquire the basic principles of optics. It covers such important topics as optical signal processing, holography, tomography, holographic radars, fiber optical communication, electro- and acousto-optic devices, and integrated optics (including optical bistability). As a basis for understanding these topics, the first few chapters give easy-to-follow explanations of diffraction theory, Fourier transforms, and geometrical optics. Practical examples, such as the video disk, the Fresnel zone plate, and many more, appear throughout the text, together with numerous solved exercises. There is an entirely new section in this updated edition on 3-D imaging.

  15. An all-optical spatial light modulator for field-programmable silicon photonic circuits

    CERN Document Server

    Bruck, Roman; Lalanne, Philippe; Mills, Ben; Thomson, David J; Mashanovich, Goran Z; Reed, Graham T; Muskens, Otto L

    2016-01-01

    Reconfigurable photonic devices capable of routing the flow of light enable flexible integrated-optic circuits that are not hard-wired but can be externally controlled. Analogous to free-space spatial light modulators, we demonstrate all-optical wavefront shaping in integrated silicon-on-insulator photonic devices by modifying the spatial refractive index profile of the device employing ultraviolet pulsed laser excitation. Applying appropriate excitation patterns grants us full control over the optical transfer function of telecommunication-wavelength light travelling through the device, thus allowing us to redefine its functionalities. As a proof-of-concept, we experimentally demonstrate routing of light between the ports of a multimode interference power splitter with more than 97% total efficiency and negligible losses. Wavefront shaping in integrated photonic circuits provides a conceptually new approach toward achieving highly adaptable and field-programmable photonic circuits with applications in optica...

  16. Optically detected electron paramagnetic resonance by microwave modulated magnetic circular dichroism

    Science.gov (United States)

    Börger, Birgit; Bingham, Stephen J.; Gutschank, Jörg; Schweika, Marc Oliver; Suter, Dieter; Thomson, Andrew J.

    1999-11-01

    Electron paramagnetic resonance (EPR) can be detected optically, with a laser beam propagating perpendicular to the static magnetic field. As in conventional EPR, excitation uses a resonant microwave field. The detection process can be interpreted as coherent Raman scattering or as a modulation of the laser beam by the circular dichroism of the sample oscillating at the microwave frequency. The latter model suggests that the signal should show the same dependence on the optical wavelength as the MCD signal. We check this for two different samples [cytochrome c-551, a metalloprotein, and ruby (Cr3+:Al2O3)]. In both cases, the observed wavelength dependence is almost identical to that of the MCD signal. A quantitative estimate of the amplitude of the optically detected EPR signal from the MCD also shows good agreement with the experimental results.

  17. Intensity modulated radiotherapy for sinonasal malignancies with a focus on optic pathway preservation

    Directory of Open Access Journals (Sweden)

    Chi Alexander

    2013-01-01

    Full Text Available Abstract Purpose To assess if intensity-modulated radiotherapy (IMRT can possibly lead to improved local control and lower incidence of vision impairment/blindness in comparison to non-IMRT techniques when treating sinonasal malignancies; what is the most optimal dose constraints for the optic pathway; and the impact of different IMRT strategies on optic pathway sparing in this setting. Methods and materials A literature search in the PubMed databases was conducted in July, 2012. Results Clinical studies on IMRT and 2D/3D (2 dimensional/3 dimensional RT for sinonasal malignancies suggest improved local control and lower incidence of severe vision impairment with IMRT in comparison to non-IMRT techniques. As observed in the non-IMRT studies, blindness due to disease progression may occur despite a lack of severe toxicity possibly due to the difficulty of controlling locally very advanced disease with a dose ≤ 70 Gy. Concurrent chemotherapy’s influence on the the risk of severe optic toxicity after radiotherapy is unclear. A maximum dose of ≤ 54 Gy with conventional fractionation to the optic pathway may decrease the risk of blindness. Increased magnitude of intensity modulation through increasing the number of segments, beams, and using a combination of coplanar and non-coplanar arrangements may help increase dose conformality and optic pathway sparing when IMRT is used. Conclusion IMRT optimized with appropriate strategies may be the treatment of choice for the most optimal local control and optic pathway sparing when treating sinonasal malignancy.

  18. Multi-tap complex-coefficient incoherent microwave photonic filters based on optical single-sideband modulation and narrow band optical filtering.

    Science.gov (United States)

    Sagues, Mikel; García Olcina, Raimundo; Loayssa, Alayn; Sales, Salvador; Capmany, José

    2008-01-01

    We propose a novel scheme to implement tunable multi-tap complex coefficient filters based on optical single sideband modulation and narrow band optical filtering. A four tap filter is experimentally demonstrated to highlight the enhanced tuning performance provided by complex coefficients. Optical processing is performed by the use of a cascade of four phase-shifted fiber Bragg gratings specifically fabricated for this purpose. PMID:18521161

  19. Generation and distribution of a wide-band continuously tunable millimeter-wave signal with an optical external modulation technique

    Science.gov (United States)

    Qi, Guohua; Yao, Jianping; Seregelyi, J.; Paquet, S.; Belisle, C.

    2005-10-01

    A new technique to generate and distribute a wide-band continuously tunable millimeter-wave signal using an optical external modulator and a wavelength-fixed optical notch filter is proposed. The optical intensity modulator is biased to suppress the odd-order optical sidebands. The wavelength-fixed optical notch filter is then used to filter out the optical carrier. Two second-order optical sidebands are obtained at the output of the notch filter. A millimeter-wave signal that has four times the frequency of the microwave drive signal is generated by beating the two second-order optical sidebands at a photodetector. Since no tunable optical filter is used, the system is easy to implement. A system using an LiNbO3 intensity modulator and a fiber Bragg grating filter is built. A stable and high spectral purity millimeter-wave signal tunable from 32 to 50 GHz is obtained by tuning the microwave drive signal from 8 to 12.5 GHz. The integrity of the generated millimeter-wave signal is maintained after transmission over a 25-km standard single-mode fiber. Theoretical analysis on the harmonic suppression with different modulation depths and filter attenuations is also discussed.

  20. Ultra-high modulation depth exceeding 2,400% in optically controlled topological surface plasmons

    Science.gov (United States)

    Sim, Sangwan; Jang, Houk; Koirala, Nikesh; Brahlek, Matthew; Moon, Jisoo; Sung, Ji Ho; Park, Jun; Cha, Soonyoung; Oh, Seongshik; Jo, Moon-Ho; Ahn, Jong-Hyun; Choi, Hyunyong

    2015-10-01

    Modulating light via coherent charge oscillations in solids is the subject of intense research topics in opto-plasmonics. Although a variety of methods are proposed to increase such modulation efficiency, one central challenge is to achieve a high modulation depth (defined by a ratio of extinction with/without light) under small photon-flux injection, which becomes a fundamental trade-off issue both in metals and semiconductors. Here, by fabricating simple micro-ribbon arrays of topological insulator Bi2Se3, we report an unprecedentedly large modulation depth of 2,400% at 1.5 THz with very low optical fluence of 45 μJ cm-2. This was possible, first because the extinction spectrum is nearly zero due to the Fano-like plasmon-phonon-destructive interference, thereby contributing an extremely small denominator to the extinction ratio. Second, the numerator of the extinction ratio is markedly increased due to the photoinduced formation of massive two-dimensional electron gas below the topological surface states, which is another contributor to the ultra-high modulation depth.