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Sample records for wavelength division multiplexed

  1. Wavelength division multiplexing a practical engineering guide

    CERN Document Server

    Grobe, Klaus

    2013-01-01

    In this book, Optical Wavelength Division Multiplexing (WDM) is approached from a strictly practical and application-oriented point of view. Based on the characteristics and constraints of modern fiber-optic components, transport systems and fibers, the text provides relevant rules of thumb and practical hints for technology selection, WDM system and link dimensioning, and also for network-related aspects such as wavelength assignment and resilience mechanisms. Actual 10/40 Gb/s WDM systems are considered, and a preview of the upcoming 100 Gb/s systems and technologies for even higher bit rate

  2. Multidiameter optical ring and Hermite-Gaussian vortices for wavelength division multiplexing-mode division multiplexing

    Science.gov (United States)

    Amphawan, Angela; Fazea, Yousef

    2016-10-01

    Optical vortices are high-capacity data carriers for mode division multiplexing (MDM) in multimode fiber (MMF). This paper reports on the MDM of a combination of helical-phased optical vortices comprising donut modes and Hermite-Gaussian (HG) modes for different radial offsets from the MMF axis. A data rate of 44 Gbps is achieved for wavelength division multiplexing-MDM of two pairs of helical-phased donut mode and HG mode at wavelengths 1550.12 and 1551.72 nm for a MMF length of 1500 m.

  3. Cascaded wavelength division multiplexing for byte-wide optical interconnects

    Energy Technology Data Exchange (ETDEWEB)

    Deri, R. J.; Garrett, H. E.; Germelos, S.; Haigh,R. E.; Henderer, B. D.; Lowry, M. E.; Walker, J.D.

    1997-11-17

    We demonstrate a wavelength division multiplexing approach for byte-wide optical interconnects over multimode fiber optic ribbon cable using filters based on common plastic ferrules. A dual wavelength link with eight cascaded filter stages exhibits bit error rates {le}l0{sup -l4}.

  4. Robust and Flexible Wavelength Division Multiplexed Optical Access Networks

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Grobe, Klaus

    Future wavelength division multiplexed (WDM) access networks should be as flexible as possible. One flexibility is port wavelength-agnosticism at the optical network unit (ONU) interface, achieved via tunable laser. At the same time such systems needs to be robust against crosstalk impairments...

  5. Optical free-space wavelength-division-multiplexing transport system.

    Science.gov (United States)

    Lin, Chun-Yu; Lin, Ying-Pyng; Lu, Hai-Han; Chen, Chia-Yi; Jhang, Tai-Wei; Chen, Min-Chou

    2014-01-15

    An optical free-space wavelength-division-multiplexing (WDM) transport system employing vertical cavity surface emitting lasers and spatial light modulators with 16-quadrature amplitude modulation orthogonal frequency-division multiplexing modulating signals over a 17.5 m free-space link is proposed and demonstrated. With the help of a low-noise amplifier and data comparator, good bit error rate performance is obtained for each optical channel. Such an optical free-space WDM transport system would be attractive for providing services including data and telecommunication services.

  6. A SURVEY ON WAVELENGTH DIVISION MULTIPLEXING (WDM NETWORKS

    Directory of Open Access Journals (Sweden)

    G. Ramesh

    2010-03-01

    Full Text Available Communication networks have emerged as a source of empowerment in today’s society. At the global level, the Internet is becoming the backbone of the modern economy. The new generations in developed countries cannot even conceive of a world without broadband access to the Internet. The inability of the current Internet infrastructure to cope with the wide variety and ever growing number of users, emerging networked applications, usage patterns and business models is increasingly being recognized worldwide. The dynamic growth of Internet traffic and its bursty nature requires high transmission rate. With the advances and the progress in Wavelength Division Multiplexing (WDM technology, the amount of raw bandwidth available in fiber links has increased to high magnitude. This paper presents a survey on WDM networks from its development to the current status. Also an analysis on buffer size in optical networks for real time traffic was performed.

  7. Dense Wavelength Division Multiplexed Quantum Key Distribution Using Entangled Photons

    CERN Document Server

    Mower, Jacob; Shapiro, Jeff H; Englund, Dirk

    2011-01-01

    Quantum key distribution (QKD) enables two parties to establish a secret key over a potentially hostile channel by exchanging photonic quantum states, relying on the fact that it is impossible for an eavesdropper to tap the quantum channel without disturbing these photons in a way that can be detected [1]. Here we introduce a large-alphabet QKD protocol that makes optimal use of temporal and spectral correlations of entangled photons, reaching the maximum number of inde- pendent basis states (the Schmidt number) and enabling extremely high information content per photon together with an optimal rate of secret key generation. This protocol, which we call 'Dense Wavelength Division Multiplexed Quantum Key Distribution' (DWDM-QKD), derives its security by the conjugate nature of the temporal and spectral entanglement of photon pairs generated by spontaneous parametric down conversion. By using a combination of spectral and temporal bases, we can adjust the protocol to be resource efficient. We show that DWDM-QKD...

  8. Novel optical add-drop multiplexer for wavelength-division-multiplexing networks

    Science.gov (United States)

    Peng, Peng-Chun; Chang, Ching-Hung; Lu, Hai-Han; Lin, Yi-Tzai; Sun, Jen-Wei; Jiang, Chang-Han

    2012-06-01

    Two novel optical add-drop multiplexer (OADM) with different self-healing functionalities for reliable wavelength-division-multiplexing networks are presented and demonstrated. Single or multiple failure-link traffics can be bi-directionally restored without the need for wavelength conversion or extra backup fiber links. To evaluate the performances of the proposed structures, a 77-channel CATV signal is experimentally transmitted with a favorable carrier-to-noise ratio (CNR), composite second-order (CSO) and composite triple beat (CTB) performances.

  9. A new synchronization scheme based on time division multiplexing and wavelength division multiplexing technology for practical quantum key distribution system

    Institute of Scientific and Technical Information of China (English)

    Zhong Ping-Ping; Zhang Hua-Ni; Wang Jin-Dong; Qin Xiao-Juan; Wei zheng-Jun; Chen Shuai; Liu Song-Hao

    2011-01-01

    Three clock synchronization schemes for a quantum key distribution system are compared experimentally through the outdoor fibre and the interaction physical model of the the clock signal and the the quantum signal in the quantum key distribution system is analysed to propose a new synchronization scheme based on time division multiplexing and wavelength division multiplexing technology to reduce quantum bits error rates under some transmission rate conditions.The proposed synchronization scheme can not only completely eliminate noise photons from the bright background light of the the clock signal, but also suppress the fibre nonlinear crosstalk.

  10. A simple wavelength division multiplexing system for active learning teaching

    Science.gov (United States)

    Zghal, Mourad; Ghalila, Hassen; Ben Lakhdar, Zohra

    2009-06-01

    The active learning project consists in a series of workshops for educators, researchers and students and promotes an innovative method of teaching physics using simple, inexpensive materials that can be fabricated locally. The objective of the project is to train trainers and inspire students to learn physics. The workshops are based on the use of laboratory work and hands-on activities in the classroom. The interpretation of these experiments is challenging for some students, and the experiments can lead to a significant amount of discussion. The workshops are organized within the framework of the project ``Active Learning in Optics and Photonics" (ALOP) mainly funded by UNESCO, with the support of ICTP (Abdus Salam International Centre for Theoretical Physics) and SPIE. ALOP workshops offer high school, college or university physics teachers the opportunity to improve their conceptual understanding of optics. These workshops usually run for five days and cover several of the topics usually found in any introductory university physics program. Optics and photonics are used as subject matter because it is relevant as well as adaptable to research and educational conditions in many developing countries [1]. In this paper, we will mainly focus on a specific topic of the ALOP workshops, namely optical communications and Wavelength Division Multiplexing technology (WDM). This activity was originally developed by Mazzolini et al [2]. WDM is a technology used in fibre-optic communications for transmitting two or more separate signals over a single fibre optic cable by using a separate wavelength for each signal. Multiple signals are carried together as separate wavelengths of light in a multiplexed signal. Simple and inexpensive WDM system was implemented in our laboratory using light emitting diodes or diode lasers, plastic optical fibres, a set of optical filters and lenses, prism or grating, and photodiodes. Transmission of audio signals using home-made, simple

  11. Cyclic polling-based dynamic wavelength and bandwidth allocation in wavelength division multiplexing passive optical networks

    Institute of Scientific and Technical Information of China (English)

    Zhengcheng Xie; Hui Li; Yuefeng Ji

    2009-01-01

    Cyclic polling-based dynamic wavelength and bandwidth allocation algorithm supporting differentiated classes of services in wavelength division multiplexing (WDM) passive optical networks (PONs) is proposed. In this algorithm, the optical line terminal (OLT) polls for optical network unit (ONU) requests to transmit data in a cyclic manner. Services are categorized into three classes: expedited forward (EF) priority, assured forwarding (AF) priority, and best effort (BE) priority. The OLT assigns bandwidth for different priorities with different strategies. Simulation results show that the proposed algorithm saves a lot of downstream bandwidth under low load and does not show the light-load penalty compared with the simultaneous and interleaved polling schemes.

  12. A Four-Wavelength All-Fibre Laser for Wavelength Division Multiplexing System

    Institute of Scientific and Technical Information of China (English)

    DING Lei; KAI Gui-Yun; XU Yan-Jun; GUAN Bai-Ou; YUAN Shu-Zhong; DONG Xiao-Yi; GE Chun-Feng

    2001-01-01

    A novel four-wavelength all-fibre laser based on fibre Bragg gratings is presented. The four wavelengths are 1555.8, 1556.6, 1557.4 and 1558.2nm, respectively. Each output laser is<0.3nm in line-width and >1 mW in power. The suppression ratio between adjacent wavelengths is >30dB. The laser was applied in a wavelength division multiplexing (WDM) system and the 100km transmission of 1.2 Gb/s nonreturn-to-zero code, 1.2 Gb/s return-to-zero code, 2.5 GHz analogue signal and 5 GHz analogue signal was realized with it.

  13. QoS Aware Wavelength Assignment in Wavelength Division Multiplexing Based Optical Networks

    Directory of Open Access Journals (Sweden)

    U. Mahmud

    2015-01-01

    Full Text Available Wavelength Division Multiplexing (WDM is used in optical networks to implement data circuits. These circuits allow exchange of information as a measure of wavelength in optical domain. Quality of Service (QoS provisioning is one of the issues in WDM optical networks. This paper discusses different QoS aware Routing and Wavelength Assignment (RWA algorithms. Some unaddressed issues are identified that include the effects of degraded performance, traffic patterns and type of QoS service for users. A software module is proposed that calculates a ‘D’ factor facilitating in the wavelength assignment for QoS provisioning. This module is designed to work in conjunction with existing RWA algorithms.

  14. Energy efficient flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network with pay as you grow deployment

    Science.gov (United States)

    Garg, Amit Kumar; Madavi, Amresh Ashok; Janyani, Vijay

    2017-02-01

    A flexible hybrid wavelength division multiplexing-time division multiplexing passive optical network architecture that allows dual rate signals to be sent at 1 and 10 Gbps to each optical networking unit depending upon the traffic load is proposed. The proposed design allows dynamic wavelength allocation with pay-as-you-grow deployment capability. This architecture is capable of providing up to 40 Gbps of equal data rates to all optical distribution networks (ODNs) and up to 70 Gbps of a asymmetrical data rate to the specific ODN. The proposed design handles broadcasting capability with simultaneous point-to-point transmission, which further reduces energy consumption. In this architecture, each module sends a wavelength to each ODN, thus making the architecture fully flexible; this flexibility allows network providers to use only required OLT components and switch off others. The design is also reliable to any module or TRx failure and provides services without any service disruption. Dynamic wavelength allocation and pay-as-you-grow deployment support network extensibility and bandwidth scalability to handle future generation access networks.

  15. In-plane wavelength division de-multiplexing using photonic crystals

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Harpøth, Anders; Hede, K. K.;

    We demonstrate a novel concept for in-plane coarse wavelength division de-multiplexing in integrated photonic circuits utilizing planar photonic crystal waveguides (PhCWs) fabricated in a silicon-on-insulator material. The filtering of wavelength channels is realized by shifting the cut-off frequ......We demonstrate a novel concept for in-plane coarse wavelength division de-multiplexing in integrated photonic circuits utilizing planar photonic crystal waveguides (PhCWs) fabricated in a silicon-on-insulator material. The filtering of wavelength channels is realized by shifting the cut...

  16. 100G shortwave wavelength division multiplexing solutions for multimode fiber data links

    DEFF Research Database (Denmark)

    Cimoli, Bruno; Estaran Tolosa, Jose Manuel; Rodes Lopez, Guillermo Arturo

    2016-01-01

    We investigate an alternative 100G solution for optical short-range data center links. The presented solution adopts wavelength division multiplexing technology to transmit four channels of 25G over a multimode fiber. A comparative performance analysis of the wavelength-grid selection for the wav...

  17. Integrated three channel laser and optical multiplexer for narrowband wavelength division multiplexing

    Science.gov (United States)

    Ragdale, C. M.; Reid, T. J.; Reid, D. C. J.; Carter, A. C.

    1994-05-01

    The fabrication and characterization of a monolithically integrated three channel narrowband wavelength multiplexer and DBR laser are reported. The multiplexers include Bragg gratings with an extinction ratio of greater than 20 dB anda bandwidth of approximately 1 nm to give channel spacings of less than 10 nm.

  18. Optical Code-Division Multiple-Access and Wavelength Division Multiplexing: Hybrid Scheme Review

    Directory of Open Access Journals (Sweden)

    P. Susthitha Menon

    2012-01-01

    Full Text Available Problem statement: Hybrid Optical Code-Division Multiple-Access (OCDMA and Wavelength-Division Multiplexing (WDM have flourished as successful schemes for expanding the transmission capacity as well as enhancing the security for OCDMA. However, a comprehensive review related to this hybrid system are lacking currently. Approach: The purpose of this paper is to review the literature on OCDMA-WDM overlay systems, including our hybrid approach of one-dimensional coding of SAC OCDMA with WDM signals. In addition, we present an additional review of other categorios of hybrid WDM/OCDMA schemes, where codes of OCDMA can be employed on each WDM wavelength. Furthermore, an essential background of OCDMA, recent coding techniques and security issues are also presented. Results: Our results indicate that the feasibility of transmitting both OCDMA and WDM users on the same spectrum band can be achieved using MQC family code with an acceptable performance as well as good data confidentiality. In addition, the WDM interference signals can be suppressed properly for detection of optical broadband CDMA using notch filters. Conclusion: The paper provides a comprehensive overview of hybrid OCDMA-WDM systems and can be used as a baseline study for other scientists in the similar scope of research.

  19. Integrated optical devices for wavelength division multiplexing using PECVD and direct UV writing techniques

    DEFF Research Database (Denmark)

    Zauner, Dan; Leistiko, Otto

    1999-01-01

    Wavelength division multiplexing (WDM) is the currents tep in the development of optical telecommunication. The emphasis of the project is to explore the exisiting photonic technology to realize integrated optical structures for WDM systems. Two methods of fabricting silica on silicon buried...

  20. Security risk assessment of the primary layer of wavelength division multiplexing passive optical network

    Science.gov (United States)

    Koudelka, Petr; Siska, Petr; Latal, Jan; Poboril, Radek; Hajek, Lukas; Kepak, Stanislav; Vasinek, Vladimir

    2015-01-01

    Next-generation passive optical access networks come to the fore nowadays. These optical next-generation networks are the response to the increasing qualitative requirements from end users. Technologies using Time Division Multiplexing include NG-PON (XG-PON 1 and XG-PON 2) and 10GEPON. Their advantage is the applicability to older topologies, which are operated by the original technology of passive optical access networks. Wavelength Division Multiplexing Passive Optical Network (WDM-PON) is an alternative also belonging to next-generation networks. Time Division Multiplexing is in this case replaced by Wavelength Division Multiplexing. Certain variants of WDM-PON use a combination of broadband light source, optical circulator, optical phased array and tunable FP laser. Construction of the terminal units (ONU) is advantageous because it can always tune in to the appropriate wavelength in the given optical DWDM channel (100 GHz). The disadvantage is the increased security risk on the primary layer due to channel crosstalk in an optical phased array (AWG). The aim of this paper is to assess the degree of security risk in real conditions. The article includes both simulation and real measurements in C + L bands with 100 GHz DWDM spacing.

  1. Analysis of subsystems in wavelength-division-multiplexing networks

    DEFF Research Database (Denmark)

    Liu, Fenghai

    2001-01-01

    of interferometric crosstalk; the model has been used in calculation of the possible size of wavelength routing networks using arrayed-waveguide-grating (AWG) routers, and in calculation of the number of wavelengths that can be handled in a new 2×2 multiwavelength cross connect. A method to measure dispersion...

  2. A 16x1 wavelength division multiplexer with integrated distributed Bragg reflector lasers and electroabsorption modulators

    Science.gov (United States)

    Young, M. G.; Koren, U.; Miller, B. I.; Newkirk, M. A.; Chien, M.; Zirngibl, M.; Dragone, C.; Tell, B.; Presby, H. M.; Raybon, G.

    1993-08-01

    We demonstrate the integrated operation of a 16x1 wavelength-division multiplexed (WDM) source with distributed Bragg reflector (DBR) lasers and electroabsorption modulators. By using repeated holographic exposures and wet chemical etching, 16 different wavelengths from 1.544 to 1.553 micron with an average channel spacing of 6 angstroms are obtained. A high-performance combiner is used to obtain a very uniform coupling into the single-output waveguide, and with the integration of an optical amplifier an average optical power of -8 dBm per channel is coupled into a single-mode fiber.

  3. Enterprise virtual private network (VPN) with dense wavelength division multiplexing (DWDM) design

    Science.gov (United States)

    Carranza, Aparicio

    An innovative computer simulation and modeling tool for metropolitan area optical data communication networks is presented. These models address the unique requirements of Virtual Private Networks for enterprise data centers, which may comprise a mixture of protocols including ESCON, FICON, Fibre Channel, Sysplex protocols (ETR, CLO, ISC); and other links interconnected over dark fiber using Dense Wavelength Division Multiplexing (DWDM). Our models have the capability of designing a network with minimal inputs; to compute optical link budgets; suggest alternative configurations; and also optimize the design based on user-defined performance metrics. The models make use of Time Division Multiplexing (TDM) wherever possible for lower data rate traffics. Simulation results for several configurations are presented and they have been validated by means of experiments conducted on the IBM enterprise network testbed in Poughkeepsie, N.Y.

  4. Technical study of visible light wavelength division multiplexing using polymer optical fiber

    Institute of Scientific and Technical Information of China (English)

    Yongsheng Zhang; Hui Ma; Tao Zhang; Zhuo Wang; Dong Wang; Rongsheng Zheng; Haipeng Yang; Hai Ming

    2005-01-01

    Visible light wavelength division multiplexing (VWDM) experiment was performed using polymer optical fiber (POF). Lights of two different wavelengths (650 and 530 nm) were sent to a single POF. Red light (650 nm) was used for 100-Mb/s full duplex IP data transmission and green light (530 nm) was used for voice signal transmission. Light sources are light-emitting diodes (LEDs). A POF coupler (splitter) and the prisms were employed as multiplexer and demultiplexer, respectively. The channel isolation and insert loss were measured, which are 20.5 and 17.65 dB for 650-nm channel respectively, and 19.16 and 20.55 dB for 530 nm one respectively.

  5. Analysis of Doppler-effeet on satellite constellations with wavelength division multiplexing architectures

    Institute of Scientific and Technical Information of China (English)

    Qinglong Yang; Liying Tan; Jing Ma

    2009-01-01

    With the development of optical space communications, a global space-based optical backbone network is currently proposed by using broadband laser inter-satellite links (ISLs) which enable routing traffic through the space. Satellite optical networking techniques based on wavelength division multiplexing (WDM) ISLs can transit significantly high data rates signals. In this letter, a new function of wavelength excursion due to Doppler-effect is developed for the ISLs, considering the conception of pointing ahead mechanism. The characteristic of wavelength excursion induced by Doppler-effect is examined in one of low earth orbit (LEO) satellite constellation networks named the next-generation LEO system (NeLS) with WDM ISLs assumed, and the influence on its communications caused by wavelength excursion is analyzed.

  6. Optimization of Dense Wavelength Division Multiplexing demultiplexer with 25GHz uniform channel spacing

    CERN Document Server

    Balaji, Venkatachalam Rajarajan; Robinson, Savarimuthu

    2016-01-01

    In this paper,we propose a four channel Dense Wavelength Division Multiplexing demultiplexer with two dimensional photonic crystal square resonant cavity that fulfill the ITU-T recommendation of G.694.1 DWDM systems.DWDM demultiplexer consists of a waveguide and Microscopic Square Resonant (MSR) cavity to enable filtering of the desired wavelength. The MSR cavity design has inner rods, outer rods and coupling rods. As the radius of the inner rod in MSR cavity changes, the cavity has the ability to filter different ITU.T G.6941 standard wavelengths like 1555.3 nm, 1555.5 nm, 1555.7 nm, and 1555.9 nm with 0.2 nm / 25 GHz channel spacing. From the simulation of various wavelengths, helps achievement of the quality factor of 8000, uniform spectral linewidth of 0.2 nm, transmission efficiency of 100 %, crosstalk of -42 dB and footprint is about 395 micro meter square.

  7. Design and Realization of Uniform Fiber Bragg Grating Used in Dense Wavelength Division Multiplexing Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Relation of optical properties in a uniform fiber Bragg grating(FBG) with its grating parameters and the laser beam engraving conditions is analyzed. The principle and method for designing the uniform FBG used in dense wavelength division multiplexing(DWDM) system is given. By adopting the double exposure technique, with a uniform phase mask and Gaussian laser beam, the uniform FBG used in DWDM system is designed and engraved, whose bandwidth of the main reflection band is about 0.4nm and 0.7nm at -5dB and -25dB respectively.

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

    Science.gov (United States)

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

    2016-08-10

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

  9. ONU migration in dynamic Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON).

    Science.gov (United States)

    Yang, Hongyang; Sun, Weiqiang; Hu, Weisheng; Li, Jun

    2013-09-09

    We propose a novel Optical Network Units (ONU) migration mechanism within the Time and Wavelength Division Multiplexed PON (TWDM-PON) framework by rearranging the working ONUs to a minimum number of wavelengths and turning off the rest to save power. We show through simulation that the number of working wavelengths can be minimized up to a theoretical lower bound, e.g. 23%, under the typical ONU online profiles. We further investigate how the migration interval and delay influence the user Service Level Agreement (SLA). We find that under the example ONU online profiles, 99.99% ONU SLA can be realized with the migration delay of 1000 milli-seconds. However to realize 99.999% ONU SLA, the migration delay must be 100 milli-seconds or lower.

  10. Wavelength Division Multiplexing Passive Optical Network modeling Using Optical System Simulator

    Directory of Open Access Journals (Sweden)

    Nahla Abdulrahman Hussain

    2015-09-01

    Full Text Available Due to the continuing demand for larger bandwidth, the optical transport becoming general in the access network. Using optical fiber technologies, the communications infrastructure becomes powerful, providing very high speeds to transfer a high capacity of data. Existing telecommunications infrastructures is currently widely used Passive Optical Network that apply Wavelength Division Multiplexing (WDM and is awaited to play an important role in the future Internet supporting a large diversity of services and next generation networks. This paper presents a design of WDM-PON network, the simulation and analysis of transmission parameters in the Optisystem 7.0 environment for bidirectional traffic. The simulation shows the behavior of optical fiber links when the signal passes through all the components such as optical fiber, splitters, multiplexers then find a good quality of signal in all receivers. The system performance is presented through various parameters such as BER analyzer and the Eye Diagram.

  11. Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy

    Directory of Open Access Journals (Sweden)

    Alexander Klein

    2014-11-01

    Full Text Available We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS with the enhanced noise rejection of wavelength modulation spectroscopy (WMS. In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS and an additional 20 kHz sinusoidal modulation (WMS. The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 µm for H2O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K. A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer.

  12. Rapid, time-division multiplexed, direct absorption- and wavelength modulation-spectroscopy.

    Science.gov (United States)

    Klein, Alexander; Witzel, Oliver; Ebert, Volker

    2014-11-14

    We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced noise rejection of wavelength modulation spectroscopy (WMS). In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS) spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS) and an additional 20 kHz sinusoidal modulation (WMS). The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 µm for H2O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K). A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer.

  13. Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy

    Science.gov (United States)

    Klein, Alexander; Witzel, Oliver; Ebert, Volker

    2014-01-01

    We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced noise rejection of wavelength modulation spectroscopy (WMS). In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS) spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS) and an additional 20 kHz sinusoidal modulation (WMS). The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 μm for H2O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K). A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer. PMID:25405508

  14. Design of virtual private networks (VPNs) over optical wavelength-division-multiplexed (WDM) networks

    Science.gov (United States)

    Ramamurthy, Byrav; Ramakrishnan, Ashok

    2000-09-01

    The bandwidth requirements of the Internet are increasing every day and there are newer and more bandwidth-thirsty applications emerging on the horizon. Wavelength division multiplexing (WDM) is the next step towards leveraging the capabilities of the optical fiber, especially for wide-area backbone networks. Virtual private networks are seen as the killer applications of tomorrow, and a great amount of research and development effort is being channeled into finding efficient ways for implementing them. In our work, we introduce the notion of VPNs operating over optical wavelength-routed WDM backbone networks. We formulate the problem of VPN design over optical WDM networks as an integer linear problem. A new method to deal with traffic from diverse VPNs is introduced and its performance analyzed.

  15. Data Optical Networking Architecture Using Wavelength-Division Multiplexing Method for Optical Sensors

    Science.gov (United States)

    Nguyen, Hung D.

    2008-01-01

    Recently there has been a growth in the number of fiber optical sensors used for health monitoring in the hostile environment of commercial aircraft. Health monitoring to detect the onset of failure in structural systems from such causes as corrosion, stress corrosion cracking, and fatigue is a critical factor in safety as well in aircraft maintenance costs. This report presents an assessment of an analysis model of optical data networking architectures used for monitoring data signals among these optical sensors. Our model is focused on the design concept of the wavelength-division multiplexing (WDM) method since most of the optical sensors deployed in the aircraft for health monitoring typically operate in a wide spectrum of optical wavelengths from 710 to 1550 nm.

  16. Optoelectronics for high-speed, wavelength-division- multiplexed optical communications networks

    Science.gov (United States)

    Hudgings, Janice Anne

    1999-11-01

    All-optical wavelength division multiplexed (WDM) communications networks have the potential to revolutionize future high-speed communications. All- optical networks offer enormous bandwidth capacity on the order of 25 THz, which is orders of magnitude greater than the capacity of radio or copper coaxial cable. In addition, wavelength division multiplexing offers a natural method of supporting with a single network multiple simultaneous applications with widely varying bandwidth requirements, modulation formats, and quality of service requirements. However, future implementation of all-optical WDM networks relies on further development of optical device technology. We present an experimental demonstration of a step- tunable, all-optical wavelength converter using cavity- enhanced four wave mixing (FWM) in a semiconductor laser. The converter is modulation format transparent, has a high conversion efficiency (> -10 dB), and is step- tunable over a large conversion range (> 2.5 THz). In addition, we derive a mathematical model of the wavelength converter, which is used to simulate step- tuning and to examine the relationship between the conversion efficiency and information bandwidth of the device. Likewise, the development of appropriate optical sources is critical to the success of all-optical communications networks. Vertical-cavity surface-emitting lasers (VCSELs) are rapidly emerging as strong competitors to the conventional edge-emitting semiconductor lasers. We have developed a novel three-contact VCSEL with an intracavity quantum-well absorber. The three-contact design of this structure enables independent control of the gain and absorber regions. If the VCSEL is designed such that the lasing wavelength is shorter than the bandedge of the intracavity absorber, the laser exhibits broad negative differential resistance, due to changes in the cavity photon density as the relative absorption is varied. With this design, the device is useful as an integrated

  17. Feasibility of quantum key distribution through dense wavelength division multiplexing network

    CERN Document Server

    Qi, Bing; Qian, Li; Lo, Hoi-Kwong

    2010-01-01

    In this paper, we study the feasibility of conducting quantum key distribution (QKD) together with classical communication through the same optical fiber by employing dense-wavelength-division-multiplexing (DWDM) technology at telecom wavelength. The impact of the classical channels to the quantum channel has been investigated for both QKD based on single photon detection and QKD based on homodyne detection. Our studies show that the latter can tolerate a much higher level of contamination from the classical channels than the former. This is because the local oscillator used in the homodyne detector acts as a "mode selector" which can suppress noise photons effectively. We have performed simulations based on both the decoy BB84 QKD protocol and the Gaussian modulated coherent state (GMCS) QKD protocol. While the former cannot tolerate even one classical channel (with a power of 0dBm), the latter can be multiplexed with 38 classical channels (0dBm power each channel) and still has a secure distance around 10km...

  18. Wavelength division multiplexing of chaotic secure and fiber-optic communications.

    Science.gov (United States)

    Zhang, Jian-Zhong; Wang, An-Bang; Wang, Juan-Fen; Wang, Yun-Cai

    2009-04-13

    Wavelength division multiplexing (WDM) transmission of chaotic optical communication (COC) and conventional fiber-optic communication (CFOC) is numerically confirmed and analyzed. For an 80-km-long two-channel communication system, a 1-Gb/s secure message in COC channel and 10-Gb/s digital signal in CFOC channel are simultaneously achieved with 100 GHz channel spacing. Our numerical simulations demonstrate that the COC and CFOC can realize no-crosstalk transmission of 80 km when the peak power of CFOC channel is less than 8dBm. We also find that the crosstalk between COC and CFOC does not depend on channel spacing when the channel spacing exceeds 100GHz. Moreover, the crosstalk does not limit channel number by comparing the synchronization performance of COC in four- and six-channel WDM systems.

  19. Multichannel Adaptive Polarization Mode Dispersion Compensation with One Compensator in Dense Wavelength Division Multiplexing Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi; CHEN Ming-hua; ZHANG Ji-yu; XIE Shi-zhong

    2007-01-01

    A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.

  20. Experimental Study on Time-Spread/Wavelength-Hop Optical Code Division Multiplexing with Dispersion-Compensating En/Decoder

    Institute of Scientific and Technical Information of China (English)

    Hideaki; Tamai; Hideyuki; Iwamura; Naoki; Minato; Saeko; Oshiba

    2003-01-01

    10Gbit/s time-spread/wavelength-hop optical code generation and decoding are performed by dispersion-compensating fiber Bragg grating (FBG) en/decoder pair. Error-free 10km single mode fiber (SMF) transmission of 10Gbit/s optical code division multiplexing (OCDM) has been experimentally demonstrated.

  1. THESEUS: A wavelength division multiplexed/microwave subcarrier multiplexed optical network, its ATM switch applications and device requirements

    Science.gov (United States)

    Xin, Wei

    1997-10-01

    A Terabit Hybrid Electro-optical /underline[Se]lf- routing Ultrafast Switch (THESEUS) has been proposed. It is a self-routing wavelength division multiplexed (WDM) / microwave subcarrier multiplexed (SCM) asynchronous transfer mode (ATM) switch for the multirate ATM networks. It has potential to be extended to a large ATM switch as 1000 x 1000 without internal blocking. Among the advantages of the hybrid implementation are flexibility in service upgrade, relaxed tolerances on optical filtering, protocol simplification and less processing overhead. For a small ATM switch, the subcarrier can be used as output buffers to solve output contention. A mathematical analysis was conducted to evaluate different buffer configurations. A testbed has been successfully constructed. Multirate binary data streams have been switched through the testbed and error free reception ([<]10-9 bit error rate) has been achieved. A simple, intuitive theoretical model has been developed to describe the heterodyne optical beat interference. A new concept of interference time and interference length has been introduced. An experimental confirmation has been conducted. The experimental results match the model very well. It shows that a large portion of optical bandwidth is wasted due to the beat interference. Based on the model, several improvement approaches have been proposed. The photo-generated carrier lifetime of silicon germanium has been measured using time-resolved reflectivity measurement. Via oxygen ion implantation, the carrier lifetime has been reduced to as short as 1 ps, corresponding to 1 THz of photodetector bandwidth. It has also been shown that copper dopants act as recombination centers in the silicon germanium.

  2. Performance analysis of long reach colorless wavelength division multiplexed-orthogonal frequency division multiplexing-passive optical network with broadcast capability

    Science.gov (United States)

    Pandey, Gaurav; Goel, Aditya

    2016-07-01

    A colorless wavelength division multiplexed-orthogonal frequency division multiplexing-passive optical network (WDM-OFDM-PON) is presented, which is capable of supporting symmetric 10 Gbps downlink direct detection (DD) OFDM unicast signal, broadcast signal, and uplink on-off keying (OOK) signal up to 60 km that includes both single mode and dispersion compensation fiber. At each optical network unit (ONU), DD has been used to receive downlink unicast and broadcast OFDM data. A delay interferometer (DI) has been used at a central office to achieve 10 Gbps uplink signal transmission over 60 km distance utilizing a reflective semiconductor optical amplifier (bandwidth=1.5 GHz) at the ONU because DI works as a vestigial sideband filter and an optical equalizer. Broadcast channel does not affect the system performance because it generates a limited interference of the order of 0.1 to 0.28 dB to downlink and uplink channels, and this interference is distributed to every ONU. For bit error rate of 10-9, the receiver sensitivity of -24, -23.1, and -20.14 dBm is achieved by simulating downlink OFDM unicast channels, OFDM broadcast channel, and uplink OOK unicast channels, respectively, for a symmetric data rate of 10 Gbps over 60 km.

  3. Fabrication of dense wavelength division multiplexing filters with large useful area

    Science.gov (United States)

    Lee, Cheng-Chung; Chen, Sheng-Hui; Hsu, Jin-Cherng; Kuo, Chien-Cheng

    2006-08-01

    Dense Wavelength Division Multiplexers (DWDM), a kind of narrow band-pass filter, are extremely sensitive to the optical thickness error in each composite layer. Therefore to have a large useful coating area is extreme difficult because of the uniformity problem. To enlarge the useful coating area it is necessary to improve their design and their fabrication. In this study, we discuss how the tooling factors at different positions and for different materials are related to the optical performance of the design. 100GHz DWDM filters were fabricated by E-gun evaporation with ion-assisted deposition (IAD). To improve the coating uniformity, an analysis technique called shaping tooling factor (STF) was used to analyze the deviation of the optical thickness in different materials so as to enlarge the useful coating area. Also a technique of etching the deposited layers with oxygen ions was introduced. When the above techniques were applied in the fabrication of 100 GHz DWDM filters, the uniformity was better than +/-0.002% over an area of 72 mm in diameter and better than +/-0.0006% over 20mm in diameter.

  4. Survivable architectures for time and wavelength division multiplexed passive optical networks

    Science.gov (United States)

    Wong, Elaine

    2014-08-01

    The increased network reach and customer base of next-generation time and wavelength division multiplexed PON (TWDM-PONs) have necessitated rapid fault detection and subsequent restoration of services to its users. However, direct application of existing solutions for conventional PONs to TWDM-PONs is unsuitable as these schemes rely on the loss of signal (LOS) of upstream transmissions to trigger protection switching. As TWDM-PONs are required to potentially use sleep/doze mode optical network units (ONU), the loss of upstream transmission from a sleeping or dozing ONU could erroneously trigger protection switching. Further, TWDM-PONs require its monitoring modules for fiber/device fault detection to be more sensitive than those typically deployed in conventional PONs. To address the above issues, three survivable architectures that are compliant with TWDM-PON specifications are presented in this work. These architectures combine rapid detection and protection switching against multipoint failure, and most importantly do not rely on upstream transmissions for LOS activation. Survivability analyses as well as evaluations of the additional costs incurred to achieve survivability are performed and compared to the unprotected TWDM-PON. Network parameters that impact the maximum achievable network reach, maximum split ratio, connection availability, fault impact, and the incremental reliability costs for each proposed survivable architecture are highlighted.

  5. 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.

  6. Reflective variable optical attenuators and fibre ring lasers for wavelength-division multiplexing systems

    Science.gov (United States)

    Liu, He Liang

    Wavelength division multiplexing (WDM) optical fibre system is an important enabling technology to fulfill the demands for bandwidth in the modern information age. The main objective of this project is to study novel devices with the potential to enhance the performance of WDM systems. In particular, a novel reflective variable optical attenuator (RVOA) used for dynamic gain equalization (DGE) and fibre lasers based on an entirely new type of erbium-doped fibres with ultrawide tuning range were investigated theoretically and experimentally. We proposed a new type of RVOA device which could be potentially integrated with arrayed waveguide grating (AWG) to reduce the cost of DGE substantially. Initially, fibre-based RVOAs, fabricated with optical fibre components such as fibre coupler and Faraday rotator mirror, were investigated theoretically and experimentally. Larger attenuation range up to 22 dB was realized for fibre coupler-based ROVA with a Faraday rotator mirror and its polarization-dependent loss is about 0.5 dB. Then polymeric waveguide-based RVOAs were investigated theoretically and experimentally. Using an epoxy Novolak resin as core material and an UV-cured resin (Norland's NOA61) as cladding material, a polymeric waveguide RVOA was successfully fabricated. The dynamic 15 dB attenuation range was achieved and the PDL was less than 0.2 dB. The measured insertion loss of the polymeric waveguide RVOA was too large (about 18 dB) and was mainly induced by coupling loss, material loss and poor alignment. In the second part of the study, fibre ring lasers with continuous wavelength tuning over wide wavelength range and fibre ring lasers with discrete wavelength tuning were investigated. Tunable lasers are important devices in WDM systems because they could be employed as reserved sources and therefore avoiding the need to stock large inventory of lasers to cover the ITU-wavelength grid. In this project, erbium ions doped bismuth oxide glass fibres instead of

  7. Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy

    OpenAIRE

    Alexander Klein; Oliver Witzel; Volker Ebert

    2014-01-01

    We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced nois...

  8. Structuring waveguide-grating-based wavelength-division multiplexing/optical code division multiple access network codecs over topology of concentric circles

    Science.gov (United States)

    Huang, Jen-Fa; Nieh, Ta-Chun; Chen, Kai-Sheng

    2013-01-01

    The cyclic period and free spectral range of arrayed-waveguide gratings (AWG) in a wavelength-division multiplexing/optical code division multiple access optical code division multiple access network are exploited. The total optical network unit (ONU) of network capacity is partitioned into groups of different wavelength in accordance with the geographical location of subscribers based on the radial distance of the ONU to the optical line terminal. Combining concentric circles round by round for ONU groups enables a fixed round-trip time in the data transmission and a significant increase in system performance. Using AWG router, the proposed topology of concentric circles retains signature orthogonality and minimizes wavelength collisions on the photo-detector. Furthermore, the adoption of extended M-sequence codes corresponding to the AWG codec provides a simpler, more efficient coding procedure and accommodates more users in a single group.

  9. Ultra fast quantum key distribution over a 97 km installed telecom fiber with wavelength division multiplexing clock synchronization.

    Science.gov (United States)

    Tanaka, Akihiro; Fujiwara, Mikio; Nam, Sae W; Nambu, Yoshihiro; Takahashi, Seigo; Maeda, Wakako; Yoshino, Ken-ichiro; Miki, Shigehito; Baek, Burm; Wang, Zhen; Tajima, Akio; Sasaki, Masahide; Tomita, Akihisa

    2008-07-21

    We demonstrated ultra fast BB84 quantum key distribution (QKD) transmission at 625 MHz clock rate through a 97 km field-installed fiber using practical clock synchronization based on wavelength-division multiplexing (WDM). We succeeded in over-one-hour stable key generation at a high sifted key rate of 2.4 kbps and a low quantum bit error rate (QBER) of 2.9%. The asymptotic secure key rate was estimated to be 0.78- 0.82 kbps from the transmission data with the decoy method of average photon numbers 0, 0.15, and 0.4 photons/pulse.

  10. Stresses and Temperature Stability of Dense Wavelength Division Multiplexing Filters Prepared by Reactive Ion-Assisted E-Gun Evaporation

    Science.gov (United States)

    Wei, Chao-Tsang; Shieh, Han-Ping D.

    2005-10-01

    In this paper, we report the in situ measurement of the temperature stability of narrow-band-pass filters on different types of substrate, for dense wavelength division multiplexing (DWDM) filters in optical-fiber transmission systems. The DWDM filters were designed as all-dielectric Fabry-Perot filters and fabricated by reactive ion-assisted deposition. Ta2O5 and SiO2 were used as high- and low-refractive-index layers, respectively, for constructing the DWDM filters. The accuracy and stability of the coating process were evaluated for fabricating the DWDM filters for the temperature stability of the center wavelength. The center wavelength shift was determined to be greatly dependent on the coefficient of thermal expansion of the substrate on which the filter is deposited.

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

    Directory of Open Access Journals (Sweden)

    Abd El-Naser A. Mohammed

    2010-09-01

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

  12. Impact of polarization mode dispersion and nonlinear effect on 40 Gbit/s dense wavelength division multiplexing system

    Institute of Scientific and Technical Information of China (English)

    SUN Xue-ming; ZHANG Hui-jian; ZUO Meng; GU Wan-yi; XU Da-xiong

    2006-01-01

    Dense wavelength division multiplexing (DWDM) system is the ultimate selection as an optical communication system because of its high speeds and capacities.However,the fiber nonlinear effects and polarization mode dispersion severely limit the performance of the system when signal propagates at 40 Gbit/s in a single channel.The coupled nonlinear Schr(o)dinger equations of a single channel in DWDM,which are all considered factors of group velocity dispersion (GVD),self phase modulation (SPM),cross phase modulation (XPM),four wave mixing (FWM) and polarization mode dispersion (PMD),are derived,while their number results are obtained with extended split-step Fourier method.Finally,to analyze the impacts of the fiber nonlinear effects and PMD on the optical communication system,the simulated results of an 8x40 Gbit/s DWDM system are discussed under different conditions respectively.

  13. Effect of soil temperature on one-way optical frequency transfer through dense-wavelength-division-multiplexing fibre links

    CERN Document Server

    Pinkert, T J; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

    2014-01-01

    Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fibre network are presented. The relation between soil temperature changes on a buried optical fibre and frequency changes of an optical carrier through the fibre is modelled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2 x 298 km fibre link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that one-way optical frequency dissemination is sufficiently stable to distribute and compare e.g. rubidium frequency standards over standard DWDM optical fibre networks.

  14. Pulse Restoration for Long-Distance Transmission of Wavelength Division Multiplexed Signals Using Gain Saturable Erbium-Doped Fiber Amplifiers

    Science.gov (United States)

    Singh, Surinder

    2010-05-01

    In this article, the pulse restoration of different fibers is compared to obtain the optimum fiber. The dispersion-compensated fiber, having a high ability for pulse restoration, is optimized to reduce the self-phase modulation effect by taking the effective core area of the fiber. Then the optimized dispersion-compensated fibers are used in wavelength division multiplex transmission to increase the maximum distance of transmission. Here, 16 channels with a channel spacing of 200 GHz are modulated by an optical LiNbO3 phase modulator with non-return-to-zero format and transmitted over 1,050 km by using dispersion-compensated fibers with an effective core area of 30 pm2 and erbium-doped fiber amplifiers. The adequate quality factor and output power of different channels are observed at 70 km, 350 km, and 1,050 km. As the distance is increased, the quality factor falls.

  15. Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

    Science.gov (United States)

    Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

    2015-02-01

    Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

  16. In-service communication channel sensing based on reflectometry for dynamic wavelength assigned wavelength- and time-division multiplexed passive optical network systems

    Science.gov (United States)

    Iida, Daisuke; Kuwano, Shigeru; Terada, Jun

    2015-04-01

    In future radio access systems, base stations will be mainly accommodated in wavelength- and time-division multiplexing passive optical network (PON) based mobile backhaul and fronthaul networks, and in such networks, failed connections in an optical network unit (ONU) wavelength channel will severely degrade mobile system performance. A cost-effective in-service ONU wavelength channel monitor is essential to ensure proper system operation without failed connections. To address this issue, we propose a reflectometry-based remote sensing method that provides ONU wavelength channel information with the optical line terminal-ONU distance. The proposed method enables real-time monitoring of ONU wavelength channels without data signal quality degradation and is also able to determine if the ONUs are connected to the PON. Experimental results show that it achieves wavelength channel distinction with a high distance resolution (˜10 m). Additionally, with the method, the distance resolution for distinguishing the ONUs after the PON splitter is determined by the received signal bandwidth or the test light modulation speed rather than by the pulse width as in conventional optical time-domain reflectometry.

  17. Impact of backreflections on single-fiber bidirectional wavelength-division-multiplexing passive optical networks (WDM-PONs)

    Science.gov (United States)

    Gao, Shiyu

    With increased demand for bandwidth-hungry applications such as video-on-demand, wavelength-division-multiplexing passive optical network (WDM-PON) has become a strong contender in overcoming the last mile bottle neck. However, the wide-scale deployment of WDM-PONs has been delayed mainly due to the high cost of wavelength-specific optical components. To realize cost-effective WDM-PONs, various wavelength-independent, so called colorless architectures, have been developed so that all the subscribers can have identical optical network units (ONUs). In such WDM-PONs, however, single-fiber bidirectional transmission results in degradation of system performance caused by interference between the signals and backreflections. This thesis investigates the impact of backreflections on single-fiber bidirectional WDM-PONs. A WDM-PON with various optical line terminals (OLTs) and colorless ONU configurations is presented. The dependence of the power penalty, caused by backreflections, on a variety of parameters is investigated. This includes parameters such as the source linewidths, receiver bandwidth, transmission line loss (TLL), ONU gain, chirp effect at the ONU and optical return loss (ORL), in various WDM-PON configurations. The WDM-PON with continuous wave (CW) seed light and remodulation schemes are both presented and studied experimentally. The impacts of the backreflections on the single-fiber bidirectional WDM-PON with various OLT and ONU configurations are compared and analyzed accordingly.

  18. Reconfigurable intensity modulation and direct detection optical transceivers for variable-rate wavelength-division-multiplexing passive optical networks utilizing digital signal processing-based symbol mapper

    Science.gov (United States)

    Zhang, Zhiguo; Zhang, Bingbing; Chen, Yanxu; Chen, Xue

    2017-01-01

    Variable-rate intensity modulation and direct detection-based optical transceivers with software-controllable reconfigurability and transmission performance adaptability are experimentally demonstrated, utilizing M-QAM symbol mapping implemented in MATLAB® programs. A frequency division multiplexing-based symbol demapping and wavelength management method is proposed for the symbol demapper and tunable laser management used in colorless optical network unit.

  19. Experimental performance of semiconductor optical amplifiers and praseodymium-doped fiber amplifiers in 1310-nm dense wavelength division multiplexing system

    Science.gov (United States)

    Chorchos, Lukasz; Turkiewicz, Jaroslaw P.

    2017-04-01

    One of the key optical transmission components is optical amplifiers. Studies on the amplification properties of the 1310-nm optical amplifiers are presented. The evaluated optical amplifiers are semiconductor optical amplifier (SOA) and praseodymium-doped fiber amplifier (PDFA). The study is aimed at the dynamic operation in single- and multiwavelength domains with high rate signals. The maximum obtained gain was 25.0 dB for SOA and 20.9 dB for PDFA. For the SOAs, the minimum achieved value of the receiver sensitivity was -11.5 dBm for a single channel and -11.5 dBm for a dense wavelength division multiplexing case while for PDFA those values were -11.0 dBm and -10.9, respectively. The main advantage of the PDFA in comparison to the measured SOAs is its higher saturation power. The SOAs proved to be viable candidates for high-speed amplification in the 1310-nm wavelength domain.

  20. Exploiting the Faster Than Nyquist Concept in WavelengthDivision Multiplexing Systems Using Duobinary Shaping

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    This paper begins with Nyquist wavelengthdivision multiplexing (WDM) and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference (ISI) is accepted, which violates the fundamental principle of Nyquist WDM. This results in muchrelaxed transceiver bandwidth and simpler spectral design. However, in fasterthanNyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of fasterthanNyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, lowcomplexity receivers based on fasterthanNyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.

  1. Dense wavelength-division multiplexing dispersion compensators based on chirped and apodized Fibonacci structures: CA-FC(j,n).

    Science.gov (United States)

    Golmohammadi, Saeed; Moravvej-Farshi, Mohammad Kazem; Rostami, Ali; Zarifkar, Abbas

    2008-12-10

    Chromatic dispersion compensation is an essential feature of high speed dense wavelength-division multiplexing (DWDM) systems. We propose a dispersion compensator structure whose characteristics meet the optical DWDM system requirements. The proposed structure is based on Fibonacci quasi-periodic multilayer structures composed of layers with large index differences. Studying the dispersive properties of Fibonacci structures with generation numbers j=3 and 4, and calculating group delay (GD) and group velocity dispersion (GVD) of their reflection bands, we have demonstrated that to have a smooth GD and almost a constant GVD in each band of a DWDM system, one needs not only to suitably chirp the structure refractive index profile, but also must properly apodize it. We also demonstrate the possibility of achieving high slope GDs and large GVDs by means of high order Fibonacci structures with thicker layers. Finally, by varying the layer dimensions and refractive indices as well as Fibonacci's order, one can design DWDM dispersion compensators suitable for distances as long as 220 km.

  2. Modeling interchannel four-wave mixing for 8-Ary modulated dense wavelength division multiplexing systems over dispersion map

    Science.gov (United States)

    Du, Jianxin; Shen, Ninghang; Xu, Yue

    2016-08-01

    Semianalytic models are developed to deterministically calculate the variances of degenerate and nondegenerate four-wave mixing (FWM) noises for dispersion-managed dense wavelength division multiplexing (DWDM) systems with 8-Ary modulations [i.e., 8-level amplitude- and differential phase-shift keying (8APSK) and constant-amplitude optical differential 8-level phase-shift keying (D8PSK)]. The semianalytic models include various important propagation effects for exact numerical results. A 5.28-Tb/s (40-Gs/s/ch) 100-GHz-spaced 33-channel DWDM system with a dispersion map is then numerically analyzed by using the newly derived semianalytic models. It is numerically validated that FWM impacts coming from 8APSK pump channels are more severe than those coming from D8PSK ones, where pump channels denote the channels whose energies are transferred to a probe channel through the FWM process. The numerical results show that although FWM tolerance of a central channel with 8APSK is worse than that with D8PSK, a central channel with 8APSK is still superior to that with D8PSK when some linear noises and FWM noise are simultaneously taken into account for our given system conditions, which is mainly attributed to a relatively larger minimum Euclidean distance for the 8APSK constellation than the D8PSK one.

  3. High performance guard ring P-i-N photodetectors for microwave subcarrier wavelength division multiplexed networks

    Science.gov (United States)

    Odubanjo, Babatunde A.

    This dissertation is concerned with the design and fabrication of high performance guard ring photodetectors suitable for use in very dense WDM microwave subcarrier multiplexed (SCM) networks and Passive Optical Networks (PONs). Two issues are addressed. The first obvious quantity of concern is the problem of nonlinearity distortion characteristics of the detector arising from- internal electric field perturbation due to space charge and external loading induced effects-intermodulation effects due to the mixing between different microwave subcarriers-and optical beat notes interference issue. The second is the problem of slower responses due to diffusion currents. Our investigation begins with an analytic study of the transient response of a typical p-i-n and avalanche photodetectors (APDs) to determine the origin of their nonlinearities and slow response and their suitability for use in a narrow-band receiver required for SCM networks. We found that for a single channel link where the total receiver photocurrent is of the same magnitude as the signal photocurrent, avalanche photodetectors can dramatically increase receiver sensitivity. However in microwave subcarrier multiplexed networks the photodiodes in each receiver detect all subcarrier channels therefore the total received photocurrent is greater than that of a single channel by many orders. Thus under these criteria, APDs cannot provide any improvement in the receiver sensitivity. In fact avalanche gain noise mechanism degrades the expected S/N ratio due to its intrinsic excess noise factor. Furthermore, APDs typically require large bias voltage. There is also the problem of limited gain-bandwidth product which makes avalanche photodetectors unsuitable for very dense WDM networks. The clear choice for SCM-based networks is therefore the p-i-n photodiode which is shot-noise limited in high speed applications. We use our analysis to optimize a typical p-i-n photodiode. The result is a novel guard ring

  4. Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission

    Science.gov (United States)

    Wu, Jindong; Chen, Liuhua; Li, Qingguo; Wu, Wenwen; Sun, Keyuan; Wu, Xingkun

    2011-07-01

    Four non-zero-dispersion-shifted fibers with almost the same large effective area (Aeff) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An Aeff of greater than 71 μm2 is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550nm dispersion slope from 0.072ps/nm2/km to 0.063ps/nm2/km or 0.05ps/nm2/km, increasing the 1550nm dispersion from 4.972ps/nm/km to 5.679ps/nm/km or 7.776ps/nm/km, and shifting the zero-dispersion wavelength from 1500nm to 1450nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550nm dispersion slope from 0.12ps/nm2/km to 0.085ps/nm2/km, increasing the 1550nm dispersion from -4ps/nm/km to -6.016ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.

  5. High-Q wavelength division multiplexed optoelectronic oscillator based on a cascaded multi-loop topology

    Science.gov (United States)

    Charalambous, Georgios; Hasanuzzaman, G. K. M.; Perentos, Andreas; Iezekiel, Stavros

    2017-03-01

    A WDM optoelectronic oscillator (OEO) based on a cascaded optical multi-loop configuration and multiple photodiodes is proposed and demonstrated experimentally. By employing up to three lasers widely separated in wavelength along with two cascaded multi-loop fiber sections and two photodiodes, we demonstrate OEO topologies that scale up to six effective loops revealing an ultra-high quality factor in excess of 1010 and a phase noise performance down to -119 dBc/Hz at 10 kHz offset

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

    Directory of Open Access Journals (Sweden)

    Ratna K.Z. Sahbudin

    2012-01-01

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

  7. Compact 35μm fiber coupled diode laser module based on dense wavelength division multiplexing of NBA mini-bars

    Science.gov (United States)

    Witte, U.; Traub, M.; Di Meo, A.; Hamann, M.; Rubel, D.; Hengesbach, S.; Hoffmann, D.

    2016-03-01

    We present a compact, modular and cross talk free approach for dense wavelength division multiplexing of high power diode lasers based on ultra-steep dielectric filters. The mini bars consist of 5 narrow stripe broad area emitters with a beam parameter product in the range of 2 mm mrad and a wavelength spacing of 2.5 nm between 2 adjacent emitters. Experimental results for fiber coupling (35 μm core diameter, NA < 0.2) of internally and externally stabilized diode lasers are presented. Optical losses are analyzed and alternative optical designs to overcome the current limitations of the setup are discussed.

  8. Four-fold increase in users of time-wavelength division multiplexing (TWDM) passive optical network (PON) by delayed optical amplitude modulation (AM) upstream

    Science.gov (United States)

    Kachhatiya, Vivek; Prince, Shanthi

    2016-12-01

    In this paper, we have proposed and simulated optical time division multiplexed passive optical network (TDM-PON) using delayed optical amplitude modulation (AM). Eight upstream wavelengths are demonstrated to show optical time wavelength division multiplexed (TWDM) by combining optical network units (ONU) users data at the remote node (RN). Each ONU generates 2.5 Gb/s user data, and it is modulated using novel return to zero (RZ) delayed AM. Optical TDM aggregates 10 Gb/s data per wavelength from four 2.5 Gb/s upstream user data, which facilitates four different ONU data on the same wavelength as 10 Gb/s per upstream wavelength and, simplify the laser requirements (2.5 Gb/s) at each optical network unit (ONU) transmitter. Upstream optical TWDM-PON is investigated for eight wavelengths with wavelength spacing of 100 GHz. Novel optical TDM for upstream increased the number of the simultaneous user to fourfold from conventional TWDM-PON using delayed AM with a high-quality-factor of received signal. Despite performance degradation due to different fiber reach and dispersion compensation technique, Optical TWDM link shows significant improvement regarding receiver sensitivity when compared with common TWDM link. Hence, it offers optimistic thinking to show optical TDM at this phase as one of the future direction, where complex digital signal processing (DSP) and coherent optical communication are frequently demonstrated to serve the access network. Downstream side conventional TWDM eight wavelengths are multiplexed at the OLT and sent downstream to serve distributed tunable ONU receivers through an optical distribution network (ODN). Each downstream wavelengths are modulated at the peak rate of 10 Gb/s using non-return to zero external modulation (NRZ-EM). The proposed architecture is cost efficient and supports high data rates as well as ;pay as you grow; network for both service providers and the users perspectives. Users are classified into two categories viz home

  9. Simultaneous frequency stabilization and high-power dense wavelength division multiplexing (HP-DWDM) using an external cavity based on volume Bragg gratings (VBGs)

    Science.gov (United States)

    Hengesbach, Stefan; Klein, Sarah; Holly, Carlo; Witte, Ulrich; Traub, Martin; Hoffmann, Dieter

    2016-03-01

    Multiplexing technologies enable the development of high-brightness diode lasers for direct industrial applications. We present a High-Power Dense Wavelength Division Multiplexer (HP-DWDM) with an average channel spacing of 1.7 (1.5) nm and a subsequent external cavity mirror to provide feedback for frequency stabilization and multiplexing in one step. The "self-optimizing" multiplexing unit consists of four reflective Volume Bragg Gratings (VBGs) with 99% diffraction efficiency and seven dielectric mirrors to overlay the radiation of five input channels with an adjustable channel spacing of 1-2 nm. In detail, we focus on the analysis of the overall optical efficiency, the change of the beam parameter product and the spectral width. The performance is demonstrated using five 90 μm multimode 9xx single emitters with M2angular intensity distribution changes strongly and the beam parameter product decreases by a factor of 1.2 to 1.9. Thereby the angular intensity distribution is more affected than the width of the beam waist. The spectral width per emitter decreases to 3-200 pm (FWHM) depending on the injection current and the reflectance of the feedback mirror (0.75%, 1.5%, 4%, 6% or 8%). The overall optical multiplexing efficiency ranges between 77% and 86%. With some modifications (e.g. enhanced AR-coatings) we expect 90-95%.

  10. On-chip mode division multiplexing technologies

    DEFF Research Database (Denmark)

    Ding, Yunhong; Frellsen, Louise Floor; Guan, Xiaowei

    2016-01-01

    using one-dimensional (1D) photonic crystal silicon waveguides. We furthermore use the fabricated devices to demonstrate on-chip point-to-point mode division multiplexing transmission, and all-optical signal processing by mode-selective wavelength conversion. Finally, we report an efficient silicon...

  11. Flexible tunable optical transceiver based on field-programmable gate array for time and wavelength-division multiplexed passive optical network systems

    Science.gov (United States)

    Hu, Sheng; Yu, Yonglin; Li, Cheng; Zhu, Yao; Han, Yu

    2016-08-01

    Time- and wavelength-division multiplexed passive optical networks (TWDM-PONs) have been selected by the full services access network community as the most suitable technology for next-generation optical access networks. A key technology in TWDM-PON is the colorless optical network unit transceiver. This paper proposes a flexible, tunable optical transceiver that uses directly modulated tunable lasers. Using a field-programmable gate array (FPGA), programmable reconfigurations and testing capabilities can be embedded into the transceiver in order to implement wavelength control, signal generation, pre-emphasis for upstream, and a bit error rate (BER) test for the downstream. To ensure high-quality signal generation at different bitrates, impedance matching between the laser driver circuit and the laser diodes is optimized. Using the proposed transceiver, three-section-distributed Bragg reflector tunable lasers at or below 2.5 Gb/s direct modulation through a 40-km standard mode fiber transmission were successfully implemented.

  12. Influence of four-wave mixing in short- and medium-range 1310  nm dense wavelength division multiplexing systems.

    Science.gov (United States)

    Markowski, Konrad; Chorchos, Łukasz; Turkiewicz, Jarosław Piotr

    2016-04-10

    In this paper, we demonstrate a comprehensive analysis of the impact of four-wave mixing (FWM) on the quality of transmission in short- and medium-range dense wavelength division multiplexing (DWDM) systems in the 1310 nm wavelength domain. The presented analysis proves that, for the system with uniform power per channel assignment, setting proper input channel power can substantially reduce the influence of the FWM effect on bit error rate in low channel spaced short-range systems, despite the position of the DWDM grid around the zero-dispersion wavelength. Simulations and experimental analysis of the possibility of FWM suppression have been provided. The power penalty measurements show that the influence of FWM on system performance may be as low as 0.3 dB with reasonable input power (i.e., -11  dBm per channel), making possible the transmission of data by fiber over distances of 25 km. Finally, we demonstrate that, for channel spacing as low as 120 GHz, error-free transmission in the 1310 nm wavelength domain is possible, despite high efficiency of FWM generation. The results prove that utilization of the 1310 nm wavelength domain in a system with low channel spacing, i.e., with better bandwidth allocation, is an interesting solution for data storage and processing center applications.

  13. Design of CMOS compatible and compact, thermally-compensated electro-optic modulator based on off-axis microring resonator for dense wavelength division multiplexing applications.

    Science.gov (United States)

    Haldar, Raktim; Banik, Abhik D; Varshney, Shailendra K

    2014-09-22

    In this work, we propose and demonstrate the performance of silicon-on-insulator (SOI) off-axis microring resonator (MRR) as electro-optic modulator (EOM). Adding an extra off-axis inner-ring in conventional microring structure provides control to compensate thermal effects on EOM. It is shown that dynamically controlled bias-voltage applied to the outer ring has the potency to quell the thermal effects over a wide range of temperature. Thus, besides the appositely biased conventional microring, off-axis inner microring with pre-emphasized electrical input message signal enables our proposed structure suitable for high data-rate dense wavelength division multiplexing scheme of optical communication within a very compact device size.

  14. Study on the color merging of white light and transmission properties of wavelength division multiplexing visible light communication system based on RGB light-emitting diodes

    Science.gov (United States)

    Wang, Guangye; Gao, Yingming; Wang, Jinpeng; Chen, Ailin; Li, Ping; Zou, Nianyu

    2016-10-01

    Visible light communication (VLC) systems have an advantage for simultaneously achieving communication and illumination. To strengthen the performance of VLC by using RGB light-emitting diodes (LEDs) while meeting the lighting requirements, the channel capacity and the transmission capability of the system are improved by utilizing the wavelength division multiplexing (WDM) technology. We make the chromaticity of the merged white light suitable for human eyes by the experiment. The parameters of merged white light based on RGB LEDs and the merging ratio data measured by the experiment are given. Hence, we study and analyze the eye diagrams and bit error rate (BER) of different optical channels. The simulation results show that maximum transmission rate of the output signal is up to 3.3 Gbit/s, and the BER is less than 10-5 with a transmission distance of 2.5 m while meeting standard illumination requirements.

  15. New Compensation Technique for Fiber Impairments in Ultra High Capacity Super channel Based on (QDPASK Dense wavelength division multiplex (DWDM systems

    Directory of Open Access Journals (Sweden)

    Ibrahim A.Murdas

    2017-07-01

    Full Text Available In this paper we want to increase the data rate and to get larger transmission distance, therefore we use the Advanced modulation technique QDPASK in DWDM system with low channels space. In case of long transmission distance and multi channels system both giving rise to inter channel crosstalk induced by fiber nonlinearities as a result the use of advanced modulation technique becomes difficult. In this paper Quaternary differential phase amplitude shift keying (QDPASK is designed for 32 dense wavelength division multiplexing (DWDM channels, therefore we proposed a new cascade compensation system consist of optical and digital back propagation techniques (ODBP for compensate the linear and nonlinear effects . A performance of the system was reported using QDPASK DWDM fiber-optic system for various system parameters. The research is tested in VPI maker environment.

  16. Novel wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points based on multitone generation and triple sextupling frequency

    Science.gov (United States)

    Cheng, Guangming; Guo, Banghong; Liu, Songhao; Huang, Xuguang

    2014-01-01

    An innovative wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points (AP) based on multitone generation and triple sextupling frequency is proposed and demonstrated. A dual-drive Mach-Zehnder modulator (DD-MZM) is utilized to realize the multitone generation. Even sidebands are suppressed to make the adjacent frequency separation twice the frequency of the local oscillator by adjusting the modulation voltage of the DD-MZM. Due to adopting three fiber Bragg gratings to reflect the unmodulated sidebands for uplink communications source free at optical network unit (ONU), is achieved. The system can support at least three APs at one ONU simultaneously with a 30 km single-mode fiber (SMF) transmission and 5 Gb/s data rate both for uplink and downlink communications. The theoretical analysis and simulation results show the architecture has an excellent performance and will be a promising candidate in future hybrid access networks.

  17. Energy efficiency evaluation of tree-topology 10 gigabit ethernet passive optical network and ring-topology time- and wavelength-division-multiplexed passive optical network

    Science.gov (United States)

    Song, Jingjing; Yang, Chuanchuan; Zhang, Qingxiang; Ma, Zhuang; Huang, Xingang; Geng, Dan; Wang, Ziyu

    2015-09-01

    Higher capacity and larger scales have always been the top targets for the evolution of optical access networks, driven by the ever-increasing demand from the end users. One thing that started to attract wide attention not long ago, but with at least equal importance as capacity and scale, is energy efficiency, a metric essential nowadays as human beings are confronted with severe environmental issues like global warming, air pollution, and so on. Here, different from the conventional energy consumption analysis of tree-topology networks, we propose an effective energy consumption calculation method to compare the energy efficiency of the tree-topology 10 gigabit ethernet passive optical network (10G-EPON) and ring-topology time- and wavelength-division-multiplexed passive optical network (TWDM-PON), two experimental networks deployed in China. Numerical results show that the ring-topology TWDM-PON networks with 2, 4, 8, and 16 wavelengths are more energy efficient than the tree-topology 10G-EPON, although 10G-EPON consumes less energy. Also, TWDM-PON with four wavelengths is the most energy-efficient network candidate and saves 58.7% more energy than 10G-EPON when fully loaded.

  18. Wavelength-multiplexed entanglement distribution

    Science.gov (United States)

    Lim, Han Chuen; Yoshizawa, Akio; Tsuchida, Hidemi; Kikuchi, Kazuro

    2010-08-01

    The realization of an entanglement distribution optical fiber network connecting multiple parties would permit implementation of many information security applications such as entanglement-based quantum key distribution and quantum secret sharing. However, due to material absorption and scattering in optical fiber, photons that are the carriers of quantum entanglement experience loss during propagation and the overall photon arrival rate can be very low in such a network. One way to increase photon arrival rate is to make full use of the available transmission bandwidth of optical fiber and this is achievable via wavelength-multiplexing. We review our recent work on wavelength-multiplexed entanglement distribution and discuss system design considerations from a telecommunication engineering perspective.

  19. Analysis of Signal-to-Crosstalk Ratio Variations due to Four-Wave Mixing in Dense Wavelength Division Multiplexing Systems Implemented with Standard Single-Mode Fibers

    Directory of Open Access Journals (Sweden)

    Sait Eser KARLIK

    2016-10-01

    Full Text Available In this paper, variation of the signal-to-crosstalk ratio (SXR due to effects of four-wave mixing (FWM has been analyzed on center channels of 5-, 7-, 9-channel dense wavelength division multiplexing (DWDM systems implemented with G.652 standard single-mode fibers (SSMFs for 12.5 GHz, 25 GHz, 50 GHz and 100 GHz equal channel spacing values. Center channels on such systems are the most severely impacted channels by FWM. Therefore, results obtained are the worst-case values for the DWDM system performance and important for system design. Simulations have been performed for systems using three different commercially available SMFs having different design parameter values for chromatic dispersion, dispersion slope, nonlinearity coefficient and attenuation coefficient which are all in the scope of the G.652 Recommendation of Telecommunication Standardization Sector of International Telecommunication Union (ITU-T for SSMFs. In those simulations, under the impact of FWM, variation of SXR with variations in input powers, channel spacings and link lengths have been observed. Simulation results display the combined effect of the optical fiber and system design parameters on FWM performance of DWDM systems and give important clues for not only long-haul but also access network implementations of DWDM systems.

  20. Novel Raman Parametric Hybrid L-Band Amplifier with Four-Wave Mixing Suppressed Pump for Terabits Dense Wavelength Division Multiplexed Systems

    Directory of Open Access Journals (Sweden)

    Gaganpreet Kaur

    2016-01-01

    Full Text Available We demonstrate improved performance of parametric amplifier cascaded with Raman amplifier for gain of 54.79 dB. We report amplification of L-band using 100 × 10 Gbps Dense Wavelength Division Multiplexed (DWDM system with 25 GHz channel spacing. The gain achieved is the highest reported so far with gain flatness of 3.38 dB without using any gain flattening technique. Hybrid modulated parametric pump is used for suppressing four-wave mixing (FWM around pump region, resulting in improvement of gain flatness by 2.42 dB. The peak to peak variation of gain is achieved less than 1.6 dB. DWDM system with 16-channel, 25 GHz spaced system has been analyzed thoroughly with hybrid modulated parametric pump amplified Raman-FOPA amplifier for gain flatness and improved performance in terms of BER and Q-factor.

  1. All-optical frequency downconversion technique utilizing a four-wave mixing effect in a single semiconductor optical amplifier for wavelength division multiplexing radio-over-fiber applications.

    Science.gov (United States)

    Kim, Hyoung-Jun; Song, Jong-In

    2012-03-26

    An all-optical frequency downconversion utilizing a four-wave mixing effect in a single semiconductor optical amplifier (SOA) was experimentally demonstrated for wavelength division multiplexing (WDM) radio-over-fiber (RoF) applications. Two WDM optical radio frequency (RF) signals having 155 Mbps differential phase shift keying (DPSK) data at 28.5 GHz were simultaneously down-converted to two WDM optical intermediate frequency (IF) signals having an IF frequency of 4.5 GHz by mixing with an optical local oscillator (LO) signal having a LO frequency of 24 GHz in the SOA. The bit-error-rate (BER) performance of the RoF up-links with different optical fiber lengths employing all-optical frequency downconversion was investigated. The receiver sensitivity of the RoF up-link with a 6 km single mode fiber and an optical IF signal in an optical double-sideband format was approximately -8.5 dBm and the power penalty for simultaneous frequency downconversion was approximately 0.63 dB. The BER performance showed a strong dependence on the fiber length due to the fiber dispersion. The receiver sensitivity of the RoF up-link with the optical IF signal in the optical single-sideband format was reduced to approximately -17.4 dBm and showed negligible dependence on the fiber length.

  2. A Novel Dynamic Physical Layer Impairment-Aware Routing and Wavelength Assignment (PLI-RWA) Algorithm for Mixed Line Rate (MLR) Wavelength Division Multiplexed (WDM) Optical Networks

    Science.gov (United States)

    Iyer, Sridhar

    2016-12-01

    The ever-increasing global Internet traffic will inevitably lead to a serious upgrade of the current optical networks' capacity. The legacy infrastructure can be enhanced not only by increasing the capacity but also by adopting advance modulation formats, having increased spectral efficiency at higher data rate. In a transparent mixed-line-rate (MLR) optical network, different line rates, on different wavelengths, can coexist on the same fiber. Migration to data rates higher than 10 Gbps requires the implementation of phase modulation schemes. However, the co-existing on-off keying (OOK) channels cause critical physical layer impairments (PLIs) to the phase modulated channels, mainly due to cross-phase modulation (XPM), which in turn limits the network's performance. In order to mitigate this effect, a more sophisticated PLI-Routing and Wavelength Assignment (PLI-RWA) scheme needs to be adopted. In this paper, we investigate the critical impairment for each data rate and the way it affects the quality of transmission (QoT). In view of the aforementioned, we present a novel dynamic PLI-RWA algorithm for MLR optical networks. The proposed algorithm is compared through simulations with the shortest path and minimum hop routing schemes. The simulation results show that performance of the proposed algorithm is better than the existing schemes.

  3. Overlapped frequency-time division multiplexing

    Institute of Scientific and Technical Information of China (English)

    JIANG Hui; LI Dao-ben

    2009-01-01

    A technique named overlapped frequency-time division multiplexing (OVFTDM)) is proposed in this article. The technique is derived from Nyquist system and frequency-time division multiplexing system. When the signals are compactly overlapped without the orthogonality in time domain, the technique is named overlapped time division multiplexing (OVTDM), whereas when signals are compactly overlapped without the orthogonality in frequency domain, the technique is called overlapped frequency division multiplexing (OVFDM). To further improve spectral efficiency, the OVFTDM in which signals are overlapped both in frequency domain and in time domain is explored. OVFTDM does not depend on orthogonality whatever in time domain or in frequency domain like Nyquist system or OFDM system, but on the convolutional constraint relationship among signals. Therefore, not only the spectral efficiency but also the reliability is improved. The simulations verify the validity of this theory.

  4. Orthogonal Frequency-Division Multiplexed Quantum Key Distribution

    Science.gov (United States)

    Bahrani, Sima; Razavi, Mohsen; Salehi, Jawad A.

    2015-12-01

    We propose orthogonal frequency division multiplexing (OFDM), as a spectrally efficient multiplexing technique, for quantum key distribution (QKD) at the core of trustednode quantum networks. Two main schemes are proposed and analyzed in detail, considering system imperfections, specifically, time misalignment issues. It turns out that while multiple service providers can share the network infrastructure using the proposed multiplexing techniques, no gain in the total secret key generation rate is obtained if one uses conventional all-optical passive OFDM decoders. To achieve a linear increase in the key rate with the number of channels, an alternative active setup for OFDM decoding is proposed, which employs an optical switch in addition to conventional passive circuits. We show that by using our proposed decoder the bandwidth utilization is considerably improved as compared to conventional wavelength division multiplexing techniques.

  5. Design of optical time-division multiplexed systems using the cascaded four-wave mixing in a highly nonlinear photonic crystal fiber for simultaneous time demultiplexing and wavelength multicasting

    Science.gov (United States)

    Hui, Zhan-Qiang; Zhang, Jian-Guo

    2015-07-01

    This paper reports a new design of optical time-division multiplexed (OTDM) systems that possess a functionality of simultaneous time demultiplexing and wavelength multicasting based on the cascaded four-wave mixing in a dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF). A module of OTDM demultiplexing and wavelength multicasting can be feasibly implemented by using a 3 dB optical coupler, a high-power erbium-doped fiber amplifier, a short-length DF-HNL-PCF, and a wavelength demultiplexer in the simple configuration. We also carry out an experiment on the proposed system to demonstrate the 100-10 Gbit s-1 OTDM demultiplexing with wavelength conversion simultaneously at 4 multicast wavelengths. It is shown that error-free wavelength multicasting is achieved on two wavelength channels with the minimum power penalty of 3.2 dB relative to the 10 Gbit s-1 back-to-back measurement, whereas the bit error rates of other two multicasting channels are measured to be about 10-6-10-5. Moreover, we propose the use of a proper error-correcting code to improve the multicasting performance of such an OTDM system, and our work reveals that the resulting system can theoretically support error-free multicasting of the OTDM-demultiplexed signal on four wavelength channels.

  6. 10 Gbps Colorless Optical Source in Wavelength-Division Multiplexed Passive Optical Networks for Monolithic Integration of Deep-Ridge Waveguide Electroabsorption Modulator with Planar Buried-Heterostructure Semiconductor Optical Amplifier

    Science.gov (United States)

    Kim, Dong Churl; Kim, Ki Soo; Kim, Hyun-Soo; Choi, Byung-Seok; Kwon, O.-Kyun

    2012-05-01

    For the 10 Gbps colorless optical source in wavelength-division multiplexed passive optical networks (WDM-PONs), we have fabricated a semiconductor optical amplifier-reflective electorabsorption modulator (SOA-REAM) by monolithic integration of deep-ridge waveguide REAM (DRW-REAM) with planar buried-heterostructure (PBH) SOA using a PNP-current blocking layer. The SOA-REAM has a spot-size convertor for easy fiber coupling. Using a butterfly module with an SMA connector, we have packaged the SOA-REAM. At a -10 dBm input power of 1550 nm, the saturation output power is about 6 dBm. At 10.7 Gbps, we can obtain clear eye diagrams, and the power penalty at 10-9 bit-error rate (BER) after 20 km transmission is less than 1 dB over 35 nm.

  7. The radio-on-fiber-wavelength-division-multiplexed-passive-optical network (WDM-RoF-PON) for wireless and wire layout with linearly-polarized dual-wavelength fiber laser and carrier reusing

    Science.gov (United States)

    Ji, Wei; Chang, Jun

    2013-07-01

    In this paper, we design a WDM-RoF-PON based on linearly-polarized dual-wavelength fiber laser and CSRZ-DPSK, which can achieve wire-line and wireless access synchronously. With the CSRZ-DPSK modulation, the wireless access in ONU can save RF source and the frequency of radio carrier can be controlled by OLT. The dual-wavelength fiber laser is the union light source of WDM-PON with polarization multiplexing. By the RSOA and downstream light source reusing, the ONU can save omit laser source and makes the WDM-PON to be colorless. The networking has the credible transmission property, including wireless access and fiber transmission. The networking also has excellent covering range.

  8. Wavelength division and subcarrier system based on Brillouin amplification

    Science.gov (United States)

    Lee, Yang-Han; Wu, Jingshown; Kao, Ming-Seng; Tsao, Hen-Wai

    1991-10-01

    This paper analyzes an optical wavelength division multiplexing system (WDM) with subcarrier multiplexing (SCM). The pump laser is tuned to amplify the corresponding optical carrier by fiber Brillouin amplification (FBA) in WDM for the desired group of SCM signals and then a microwave tuner is used to select the desired channel in this group. This system has the benefits of eliminating the need of polarization control, the ability of phase noise cancelling due to the 'squaring' photodetection process of the selected optical carrier together with its SCM channels, and enhancement of optical receiver sensitivities by amplification of the carrier.

  9. Spin and wavelength multiplexed nonlinear metasurface holography

    Science.gov (United States)

    Ye, Weimin; Zeuner, Franziska; Li, Xin; Reineke, Bernhard; He, Shan; Qiu, Cheng-Wei; Liu, Juan; Wang, Yongtian; Zhang, Shuang; Zentgraf, Thomas

    2016-06-01

    Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam-Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption.

  10. Monolithically integrated reconfigurable add-drop multiplexer for mode-division-multiplexing systems.

    Science.gov (United States)

    Wang, Shipeng; Wu, Hao; Tsang, Hon Ki; Dai, Daoxin

    2016-11-15

    An integrated reconfigurable optical add-drop multiplexer (ROADM) for mode-division-multiplexing systems is proposed and demonstrated for the first time, to the best of our knowledge. The present ROADM with four mode-channels is composed of a four-channel mode demultiplexer, four identical 2×2 thermo-optic Mach-Zehnder switches (MZSs), and a four-channel mode multiplexer, which are integrated monolithically on silicon. All the devices are designed for operation with TM polarization. The ROADM can add/drop any one of the mode channels freely by thermally turning on/off the corresponding MZS. For the added/dropped mode-channels, the excess loss is 1-5 dB, and the extinction ratio is 15-20 dB in the wavelength range of 1535-1565 nm.

  11. A Novel Multi-Point Fiber Optics Acetylene Sensing System Based on Dense Wavelength Division Multiplexers%基于波分复用的多点光纤乙炔传感系统

    Institute of Scientific and Technical Information of China (English)

    余贶琭; 吴重庆; 郭旋; 王智; 石梅荣; 武文彬

    2011-01-01

    The Beer-Lambert law, taking into account the pressure broadening of the absorption lines function is analyzed, then it is used for multi-point acetylene gas detection. A fiber optical multi-point acetylene sensing system using dense wavelength division multiplexers, which takes advantage of different absorption lines to tag different probes in the system, is put forward. This system is easy to build and operate, while it does not need to modulate the light source. In addition, the system has a much smaller system loss and cross talks as the consequences of employing the dense wavelength division multiplexers. Theoretical results show that the maximum sensor number of the system is eighteen with a 0.5 % sensitivity using the absorption lines from 1510 to 1540 nm. A three-point sensing system is experimentally demonstrated and the errors of the measured results are within 1.8 %.%理论分析了考虑吸收线型函数展宽时的Beer-Lambert定律,作了进一步推导并应用于多点乙炔气体监测.提出一种采用波分复用器、利用吸收峰区分不同传感点的多点光纤乙炔传感系统,系统简单易操作,无需对光源进行调制,且系统损耗与串扰小.理论分析表明当目标检测灵敏度为0.5%时,在1510~1540 nm范围内该系统最大可监测18个传感点.搭建了一个3个监测点的乙炔传感系统并验证了上述理论的可行性,各传感点的测量误差均小于1.8%.

  12. On-chip data exchange for mode division multiplexed signals.

    Science.gov (United States)

    Ye, Mengyuan; Yu, Yu; Sun, Chunlei; Zhang, Xinliang

    2016-01-11

    Data exchange is an important function for flexible optical network, and it has been extensively investigated for the time and wavelength domains. The mode division multiplexing (MDM) has been proposed to further increase the transmission capacity by carrying information on different modes with only single wavelength carrier. We propose and experimentally demonstrate a novel on-chip data exchange circuit for the MDM signals by utilizing two micro-ring resonator (MRR) based mode converters. For demonstration, single and four wavelengths non-return-to-zero on-off-keying (NRZ-OOK) signals at 10 Gb/s carried on different modes are successfully processed, with open and clear eye diagrams. Measured bit error ratio (BER) results show reasonable power penalties. The proposed circuit can be potentially used in advanced and flexible MDM optical networks.

  13. 20 × 960-Gb/s Space-division-multiplexed 32QAM transmission over 60 km few-mode fiber.

    Science.gov (United States)

    Sleiffer, V A J M; Leoni, P; Jung, Y; Surof, J; Kuschnerov, M; Veljanovski, V; Alam, S U; Richardson, D J; Grüner-Nielsen, L; Sun, Y; Corbett, B; Winfield, R; Calabrò, S; de Waardt, H

    2014-01-13

    We show transmission of 20 wavelength-division-multiplexed (WDM) × 960-Gb/s space-division-multiplexed 32QAM modulated channels (spectral efficiency (SE) of 15 bits/s/Hz) over 60 km of few-mode fiber (FMF) with inline few-mode EDFA (FM-EDFA). Soft-decision FEC was implemented and used to achieve error-free transmission.

  14. Consideration for wavelength multiplexing versus time multiplexing in optical transport network

    DEFF Research Database (Denmark)

    Limal, Emmanuel; Stubkjær, Kristian Elmholdt

    1999-01-01

    We compare optical wavelength multiplexing and time multiplexing techniquesfor optical transport network by studying the space switch sizes of OXCs andtheir interfaces as a function of the fraction of add/drop traffic....

  15. A Practical Detection System of Multiplexed Wavelength Fiber Bragg Gratings

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A practical demodulation of multiplexed wavelength FBGs is proposed. The detection wavelength of adjacent FBGs and the wavelength resolution are discussed. Experimental results show the wavelength resolution is 0.01nm and strain resolution is 8.27× 10-6.

  16. Space Division Multiplexing in Optical Fibres

    CERN Document Server

    Richardson, D J; Nelson, L E

    2013-01-01

    Optical communications technology has made enormous and steady progress for several decades, providing the key resource in our increasingly information-driven society and economy. Much of this progress has been in finding innovative ways to increase the data carrying capacity of a single optical fibre. In this search, researchers have explored (and close to maximally exploited) every available degree of freedom, and even commercial systems now utilize multiplexing in time, wavelength, polarization, and phase to speed more information through the fibre infrastructure. Conspicuously, one potentially enormous source of improvement has however been left untapped in these systems: fibres can easily support hundreds of spatial modes, but today's commercial systems (single-mode or multi-mode) make no attempt to use these as parallel channels for independent signals.

  17. Few-mode fiber technology for mode division multiplexing

    Science.gov (United States)

    Mori, Takayoshi; Sakamoto, Taiji; Wada, Masaki; Yamamoto, Takashi; Nakajima, Kazuhide

    2017-02-01

    We review recent progress on few-mode fiber (FMF) technologies for mode-division multiplexing (MDM) transmission. First, we introduce fibers for use without and with multiple-input multiple-output (MIMO) digital signal processing (DSP) to compensate for modal crosstalk, and briefly report recent work on FMF for use without/with a MIMO DSP system. We next discuss in detail a fiber for MIMO transmission systems, and show numerically that a graded-index core can flexibly tune the differential mode group delay (DMD) and a cladding trench can flexibly control the guiding mode number. We optimized the spacing of the core and trench. Accordingly, we can achieve a 6 LP (10 spatial) mode operation and a low DMD while preventing the high index difference that leads to manufacturing difficulties and any loss increase. We finally describe our experimental results for a 6 LP (10 spatial) mode transmission line for use in a C + L band wavelength-division multiplexing (WDM) MDM transmission with MIMO DSP.

  18. Time/Wavelength Fiber Bragg Grating Multiplexing Sensor Array

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel time/wavelength-multiplexed fiber Bragg grating sensor array is presented. This type of sensor array has the advantages of more points for multi-point measurement, simple structure and low cost.

  19. Pipelined asynchronous time-division multiplexing optical bus

    Science.gov (United States)

    Zheng, S. Q.; Li, Yueming

    1997-12-01

    We propose a pipelined asynchronous time-division multiplexing optical bus. Such a bus can use one of two hardwared priority schemes: the linear priority scheme and the round-robin priority scheme. Our simulation results show that the performance of the proposed bus is significantly better than the performances of known pipelined synchronous time-division multiplexing optical buses. The possibilities of using our buses to construct multichannel switches and multidimensional processor arrays are also discussed.

  20. Signal processing for on-chip space division multiplexing

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Ding, Yunhong; Xu, Jing;

    2015-01-01

    Our recent results on the demonstration of on-chip mode-division multiplexing are reviewed, with special emphasis on nonlinear all-optical signal processing. Mode-selective parametric processes are demonstrated in a silicon-on-insulator waveguide.......Our recent results on the demonstration of on-chip mode-division multiplexing are reviewed, with special emphasis on nonlinear all-optical signal processing. Mode-selective parametric processes are demonstrated in a silicon-on-insulator waveguide....

  1. Orthogonal frequency division multiplexed quantum key distribution in the presence of Raman noise

    Science.gov (United States)

    Bahrani, Sima; Razavi, Mohsen; Salehi, Jawad A.

    2016-04-01

    In this paper, we investigate the performance of orthogonal frequency division multiplexed quantum key distribution (OFDM-QKD) in an integrated quantum-classical wavelength-division-multiplexing system. The presence of an intense classical signal alongside the quantum one generates Raman background noise. Noise reduction techniques should, then, be carried out at the receiver to suppress this crosstalk noise. In this work, we show that OFDM-QKD enables efficient filtering, in time and frequency domains, making it an attractive solution for the high-rate links at the core of quantum-classical networks.

  2. Design of Hard Real-Time Scheduling Algorithm in Avionic Wavelength Division Multiplexing Network%机载波分复用网络强实时性调度算法设计

    Institute of Scientific and Technical Information of China (English)

    黄金; 许渤; 凌云; 邱昆

    2013-01-01

    与传统的商业网络不同,航空机载波分复用网络要求强实时性以保证消息的传输性能.实时调度算法是保证机载网络中消息传输性能的关键.针对机载波分复用网络的实时性要求,采用实时通信中的周期性任务模型,提出了满足机载波分复用网络实时性要求的加权轮转调度算法,其中轮转周期的选择、权值匹配方法和多信道分配方法是影响调度算法参数设计的重要过程.通过多信道分配方法有效减少了消息拆分次数;结合实例比较确定了算法中消息分配权值的计算方法;并指出了最优轮转周期无法保证最小的消息延迟时间率.研究结果对机载波分复用网络的工程设计与优化有一定的指导意义.%Different from the commercial applications, the avionic wavelength division multiplexing (WDM) network lays much emphasis on hard real-time characteristics. The real-time scheduling algorithm is a key issue to ensure the message transmission performance. According to the real-time communication requirement of avionic WDM network and the traffic characteristics of the avionic network, a weighted round robin scheduling algorithm is proposed based on the periodic task model of real-time communication to guarantee hard real-time transmission in an airborne WDM network, which is comprised of the rotation cycle selection, weights assignment scheme and multi-channel allocation method. Among them, multi-channel allocation method efficiently reduces the splitting times of the message-, combined with examples, message weights assignment scheme is determined and it is pointed out that the optimal rotation cycle cannot guarantee the minimum message delay ratio. Research results are meaningful for the design of real-time scheduling parameters and the current practice of avionic WDM network.

  3. Applications of photonic crystal in wavelength multiplex visualization

    Science.gov (United States)

    Qian, Shi; Lei, Zhang

    2016-10-01

    The triple-channel photonic crystal filters are proposed designed. These devices have advantages of better filtering effect and high wavelength accuracy. In wavelength multiplex visualization, these filters can bring different wavelength of view entering into eyes so that stereo images are formed. we discuss the problem about minimization of the angle shift .The simulation shows that higher-index material and more high-index material in a basic period can decrease the angle shift.

  4. On-chip WDM mode-division multiplexing interconnection with optional demodulation function.

    Science.gov (United States)

    Ye, Mengyuan; Yu, Yu; Chen, Guanyu; Luo, Yuchan; Zhang, Xinliang

    2015-12-14

    We propose and fabricate a wavelength-division-multiplexing (WDM) compatible and multi-functional mode-division-multiplexing (MDM) integrated circuit, which can perform the mode conversion and multiplexing for the incoming multipath WDM signals, avoiding the wavelength conflict. An phase-to-intensity demodulation function can be optionally applied within the circuit while performing the mode multiplexing. For demonstration, 4 × 10 Gb/s non-return-to-zero differential phase shift keying (NRZ-DPSK) signals are successfully processed, with open and clear eye diagrams. Measured bit error ratio (BER) results show less than 1 dB receive sensitivity variation for three modes and four wavelengths with demodulation. In the case without demodulation, the average power penalties at 4 wavelengths are -1.5, -3 and -3.5 dB for TE₀-TE₀, TE₀-TE₁ and TE₀-TE₂ mode conversions, respectively. The proposed flexible scheme can be used at the interface of long-haul and on-chip communication systems.

  5. Time-division multiplexing vs network calculus: A comparison

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang; Sørensen, Rasmus Bo; Schoeberl, Martin

    2015-01-01

    Networks-on-chip are increasingly common in modern multicore architectures. However, general-purpose networks-on-chip are not always well suited for real-time applications that require bandwidth and latency guarantees. Two approaches to provide real-time guarantees have emerged: time......-division multiplexing, where traffic is scheduled according to a precalculated static schedule, and network calculus, a mathematical framework to reason about dynamically scheduled networks. This paper compares the two approaches to provide insight into their relative advantages and disadvantages. The results show...... that time-division multiplexing leads to better worst-case latencies, while network calculus supports higher bandwidths. Furthermore, time-division multiplexing leads to a simpler hardware implementation, while dynamically scheduled networks-on-chip allow the integration of best-effort traffic in the on...

  6. 2x2 MIMO-OFDM Gigabit fiber-wireless access system based on polarization division multiplexed WDM-PON.

    Science.gov (United States)

    Deng, Lei; Pang, Xiaodan; Zhao, Ying; Othman, M B; Jensen, Jesper Bevensee; Zibar, Darko; Yu, Xianbin; Liu, Deming; Monroy, Idelfonso Tafur

    2012-02-13

    We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training-based zero forcing (ZF) channel estimation algorithm is designed to compensate the polarization rotation and wireless multipath fading. A 797 Mb/s net data rate QPSK-OFDM signal with error free (fiber followed by 3 m and 1 m air distances, respectively.

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

    Science.gov (United States)

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

    2017-01-01

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

  8. Spatial code division multiplexing in optical data processing

    Science.gov (United States)

    Zalevsky, Zeev; Mendlovic, David; Solomon, Jonathan

    2002-09-01

    The increasing popularity of optical communication has also brought a demand for broader bandwidth. The natural trend was to implement methods from traditional communication on optical fibers. One of the most effective "traditional" methods is code division multiple access (CDMA). In this paper, we suggest the use of this approach for spatial coding applied to images, and for superresolution. In spatial coding, the approach is to multiplex several filters into one plane while keeping their mutual orthogonality. It is shown that within specific restrictions the output of all the filters can be sampled in the original image resolution and fully recovered through an all-optical setup. A theoretical analysis of such a setup is brought as well as experimental demonstrations are presented. Implementation for invariant pattern recognition is suggested. In superresolution, we propose using code division multiplexing in order to transfer a wider range of frequencies. Traditional methods for super resolution have sacrificed field of view for resolution. These methods multiplexed the signal on different carriers. Code division multiplexing for such a usage, has been shown to have superior capabilities, nearing almost Shannon's channel capacity limit. To enable such multiplexing we propose a unique setup that creates an incoherent cosine transform of the image. A theoretical analysis of the setup is brought and later compared with the empirical results.

  9. DSP complexity of mode-division multiplexed receivers.

    Science.gov (United States)

    Inan, Beril; Spinnler, Bernhard; Ferreira, Filipe; van den Borne, Dirk; Lobato, Adriana; Adhikari, Susmita; Sleiffer, Vincent A J M; Kuschnerov, Maxim; Hanik, Norbert; Jansen, Sander L

    2012-05-07

    The complexities of common equalizer schemes are analytically analyzed in this paper in terms of complex multiplications per bit. Based on this approach we compare the complexity of mode-division multiplexed digital signal processing algorithms with different numbers of multiplexed modes in terms of modal dispersion and distance. It is found that training symbol based equalizers have significantly lower complexity compared to blind approaches for long-haul transmission. Among the training symbol based schemes, OFDM requires the lowest complexity for crosstalk compensation in a mode-division multiplexed receiver. The main challenge for training symbol based schemes is the additional overhead required to compensate modal crosstalk, which increases the data rate. In order to achieve 2000 km transmission, the effective modal dispersion must therefore be below 6 ps/km when the OFDM specific overhead is limited to 10%. It is concluded that for few mode transmission systems the reduction of modal delay is crucial to enable long-haul performance.

  10. Mode Division Multiplexing Exploring Hollow-Core Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Xu, Jing; Lyngso, Jens Kristian; Leick, Lasse

    2013-01-01

    We review our recent exploratory investigations on mode division multiplexing using hollow-core photonic bandgap fibers (HC-PBGFs). Compared with traditional multimode fibers, HC-PBGFs have several attractive features such as ultra-low nonlinearities, low-loss transmission window around 2 µm etc....

  11. All-optical orthogonal frequency division multiplexing (OFDM) transmitter

    DEFF Research Database (Denmark)

    2015-01-01

    The invention relates to an all-optical orthogonal frequency division multiplexing (OFDM) transmitter for generating an OFDM output signal. The transmitter comprises a first time-domain optical Fourier transform (OFT) assembly, the first OFT assembly is of a K-D-K configuration and comprises...

  12. Orthogonal frequency division multiplexing with diversity for future wireless systems

    CERN Document Server

    Le, Khoa N

    2012-01-01

    The book examines several aspects of Orthogonal Frequency Division Multiplexing (OFDM) employing linear diversity techniques such as inter-carrier interference, bit error rate, peak to average power and inter-block interference. It should be a useful reference for readers interested in modern wireless communication systems.

  13. Demonstration of 2×ONU 80 Gbps direct detection colorless polarization division multiplexing frequency division multiplexing passive optical network uplink transmission

    Science.gov (United States)

    Wang, Zhixin; Xu, Yinfan; Wang, Yanyi; Wang, Yuanquan; Chi, Nan

    2016-04-01

    In this study, we propose and experimentally demonstrate a simple direct detection passive optical network (PON) uplink transmission scheme based on frequency division multiplexing and polarization division multiplexing. Two optical network units (ONUs) are assigned to two different frequency bands at two different orthogonal polarization directions. At the optical line terminal, both ONU signals can be simultaneously detected by a single photodiode without utilizing any polarization control, polarization selection, or complicated polarization demultiplexing algorithms. As a proof-of-concept, the 2×ONU 80 Gbps 32-ary quadrature amplitude modulation Nyquist single carrier signals are successfully transmitted over 2 km standard single mode fiber or 20 km large effective area fiber with the assistance of frequency domain equalization and decision-directed least-mean-square. The measured bit error rate can be below the 7% pre-forward error correction threshold of 3.8×10-3. Meanwhile, this scheme is compatible with the widely used wavelength-division multiplexed PON, which shows the promising potential and feasibility of this proposal.

  14. Photonic digital-to-analog conversion based on wavelength multiplexing

    Science.gov (United States)

    Yang, Shuna; Hu, Miao; Chi, Hao; Li, Qiliang

    2017-10-01

    A novel photonic digital-to-analog conversion (PDAC) scheme, which is based on optical intensity weighting and multiplexing/summing of different wavelengths, is proposed. The employment of wavelength multiplexing in the system, which conducts the function of modulated light intensity summation, greatly simplifies the system complexity and improves the conversion speed/accuracy limited by large-area photo-detectors and associated electronics. A 4-bit PDAC with a conversion speed of 10 GS/s demonstrates the feasibility of the proposed scheme. In addition, the performance degradation induced by the limited extinction ratios of the applied electro-optic modulators, the synchronization errors among different wavelength channels, and the bit resolutions of the built system is also discussed.

  15. Free-space wavelength-multiplexed optical scanner.

    Science.gov (United States)

    Yaqoob, Z; Rizvi, A A; Riza, N A

    2001-12-10

    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

  16. High-precision, wavelength flexible frequency division for metrology

    NARCIS (Netherlands)

    Gross, Petra; Klein, Marvin E.; Boller, Klaus-Jochen

    2005-01-01

    We realize and investigate wavelength-flexible phase-coherent all-optical frequency division by 2. Frequency division is obtained via self-phase-locking in a degenerate continuous-wave (cw) optical parametric oscillator (OPO). The wavelength flexibility of the divider is based on the use of quasi-ph

  17. Optimization and analysis of code-division multiplexed TES microcalorimeters

    CERN Document Server

    Fowler, J W; Hilton, G C; Irwin, K D; Schmidt, D R; Stiehl, G M; Swetz, D S; Ullom, J N; Vale., L R

    2011-01-01

    We are developing code-division multiplexing (CDM) systems for transition-edge sensor arrays with the goal of reaching multiplexing factors in the hundreds. We report on x-ray measurements made with a four-channel prototype CDM system that employs a flux-summing architecture, emphasizing data-analysis issues. We describe an empirical method to determine the demodulation matrix that minimizes cross-talk. This CDM system achieves energy resolutions of between 2.3 eV and 3.0 eV FWHM at 5.9 keV.

  18. Multiplexing photons with a binary division strategy

    Science.gov (United States)

    Schmiegelow, Christian Tomás; Larotonda, Miguel Antonio

    2014-08-01

    We present a scheme to produce clock-synchronized photons from a single parametric downconversion source with a binary division strategy. The time difference between a clock and detections of the herald photons determines the amount of delay that must be imposed to a photon by actively switching different temporal segments, so that all photons emerge from the output with their wavepackets temporally synchronized with the temporal reference. The operation is performed using a binary division configuration which minimizes the passages through switches. Finally, we extend this scheme to the production of many synchronized photons and find expressions for the optimal amount of correction stages as a function of the pair generation rate and the target coherence time. Our results show that, for the generation of this heralded single-photon per output state at an optimized input photon flux, the output rate of our scheme scales essentially with the reciprocal of the target output photon number. With current technology, rates of up to 104 synchronized pairs per second could be observed with only 7 correction stages.

  19. Time-multiplexed measurements of nonclassical light at telecom wavelengths

    Science.gov (United States)

    Harder, G.; Silberhorn, C.; Rehacek, J.; Hradil, Z.; Motka, L.; Stoklasa, B.; Sánchez-Soto, L. L.

    2014-10-01

    We report the experimental reconstruction of the statistical properties of an ultrafast pulsed type II parametric down-conversion source in a periodically poled potassium titanyl phosphate waveguide at telecom wavelengths, with almost perfect photon-number correlations. We use a photon-number-resolving time-multiplexed detector based on a fiber-optical setup and a pair of avalanche photodiodes. By resorting to a germane data-pattern tomography, we assess the properties of the nonclassical light states with unprecedented precision.

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

    CERN Document Server

    Jedidi, A Ahmed

    2010-01-01

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

  1. Orthogonal Frequency Division Multiplexing System with Frequency Offset Estimation

    Directory of Open Access Journals (Sweden)

    Meghashree D.Nimje

    2013-03-01

    Full Text Available Orthogonal Frequency Division Multiplexing (OFDM system, use a large number of parallel narrowband subcarriers instead of a single wide-band carrier to transport information. Orthogonal frequency division multiplexing is the modulation technique use in digital communication systems . Carrier frequency offset occurs due to Doppler effect or noise. Carrier frequency offsets (CFOs is the Offset between the transmitter and the receiver oscillators .CFO damages the orthogonality of the carries ,resulting in degradation of the systems performance. Carrier frequency offset estimation method is discussed in this paper. In this paper one complex training sequence use, which can effectively estimate carrier frequency offset in the time domain and frequency domain. Here fine and coarse frequency is estimated to improve the improve the system performance. This paper shows the estimation range for frequency offset can be improve to large extent..

  2. An introduction to orthogonal frequency-division multiplexing

    OpenAIRE

    Edfors, Ove; Sandell, Magnus; van de Beek, Jan-Jaap; Landström, Daniel; Sjöberg, Frank

    1996-01-01

    This report is an introduction to orthogonal frequency-division multiplexing (OFDM). The focus is on signal processing areas pursued by our research group at Luleå University of Technology. We present an historical background and some frequently used system models. Typical areas of applications are also described, both wireless and wired. In addition to the general overview, the addressed areas include synchronization, channel estimation and channel coding. Both time and frequency synchroniza...

  3. Wavelength-Multiplexed Solitons in Optical Communications Networks.

    Science.gov (United States)

    Benner, Alan Frederic

    1992-01-01

    Solitons in optical fibers have proved exceedingly useful for counteracting dispersive pulse spreading in ultra-long distance data transmission in optical fibers. However, optical solitons have only been used for point-to-point communication, and have only utilized 1 [ THz] transmission bandwidth available in low-loss optical fiber. An extremely promising proposed system architecture for high-capacity multi-node communication utilizes generation, transmission, and detection of ensembles of pulses denoting data packets, encoded at 1 bit per wavelength. The use of optical solitons in such a wavelength-multiplexed packet switching network promises extremely high long distance capacity, but is complicated by nonlinear interactions between solitons during transmission. We investigate the generation, propagation, and detection of wavelength multiplexed optical soliton data packets through a combination of theoretical analysis utilizing the Inverse Scattering Transform technique, computational numerical analysis, and laboratory experimentation. The optical waveform envelopes evolve by the Nonlinear Schrodinger equation, an integrable nonlinear partial differential equation. There exists an invariant parameter domain, termed the scattering domain, which is nonlinearly related to the spatial domain, where the parameters describing a nonlinear evolving waveform either evolve linearly with time or are constant. Data may therefore be encoded upon these invariant parameters for transmission and effective detection. Through a series of four techniques, ranging from purely theoretical and exact to approximate and highly practical, we demonstrate that, given the expected restrictions on possible pulse parameters for optical communications systems, the information denoted by an ensemble of strongly interacting, wavelength-multiplexed solitons may be extracted from the frequency domain data for the waveform. This demonstrates that it is quite feasible to use solitons for long

  4. Multiplexed absorption tomography with calibration-free wavelength modulation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Weiwei; Kaminski, Clemens F., E-mail: cfk23@cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA (United Kingdom)

    2014-04-14

    We propose a multiplexed absorption tomography technique, which uses calibration-free wavelength modulation spectroscopy with tunable semiconductor lasers for the simultaneous imaging of temperature and species concentration in harsh combustion environments. Compared with the commonly used direct absorption spectroscopy (DAS) counterpart, the present variant enjoys better signal-to-noise ratios and requires no baseline fitting, a particularly desirable feature for high-pressure applications, where adjacent absorption features overlap and interfere severely. We present proof-of-concept numerical demonstrations of the technique using realistic phantom models of harsh combustion environments and prove that the proposed techniques outperform currently available tomography techniques based on DAS.

  5. Blocking Analysis of Time-Division Multiplexed Multicast Switch

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The particular switch concerned here is a Three-Stage Time-space-time (TST) interconnection network and performs the time-division circuit switching. The input and output stages are Time Slot Interchangers (TSI). The central stage is a time-multiplexed switch with two ports per address. By exploiting the channel grouping at the central stage as well as reducing the average loading at each internal frame,the three-stage multicast switch has potential to remove almost all slot contention blockings.

  6. Space division multiplexing optical communication using few-mode fibers

    Science.gov (United States)

    Weng, Yi; He, Xuan; Pan, Zhongqi

    2017-07-01

    To realize ultra-high capacity long-haul transmission, space-division multiplexing (SDM) has emerged as a promising solution, in which each data channel is modulated into an individual spatial/polarization modes in few-mode fibers (FMF) to increase the overall number of parallel channels. In this paper, we review the latest advances in SDM technology on the FMF, component, digital signal processing (DSP), as well as transmission demonstrations. First, we introduce the FMF characteristics, fabrication and manufacturing issues including modal dispersion, mode coupling, and nonlinearities. We next discuss in detail several key SDM components such as spatial multiplexers/demultiplexers (MUX/DeMUX), optical amplifiers, mode converters and SDM reconfigurable optical add-drop multiplexer (ROADM). Accordingly, we explore the DSP algorithms for SDM systems, covering least mean squares (LMS), recursive least squares (RLS), hardware complexity analysis, and mode dependent effects. Besides, a number of recent experimental validations are evaluated enabling higher transmission capacity for short, medium and long distances.

  7. Chromatic characterization of ion-exchanged glass binary phase plates for mode-division multiplexing.

    Science.gov (United States)

    Prieto-Blanco, Xesús; Montero-Orille, Carlos; Moreno, Vicente; Mateo, Eduardo F; Liñares, Jesús

    2015-04-10

    Mode-division multiplexing (MDM) in few-mode fibers is regarded as a promising candidate to increase optical network capacity. A fundamental element for MDM is a modal transformer to LP modes which can be implemented in a free-space basis by using multiregion phase plates, that is, LP plates. Likewise, several wavelengths have to be used due to wavelength multiplexing purposes, optical amplification tasks, and so on. In this work we show that efficient monolithic binary phase plates for different wavelengths can be fabricated by ion-exchange in glass and used for MDM tasks. We introduce an optical characterization method of the chromatic properties of such phase plates which combines the inverse Wentzel-Kramers-Brillouin (IWKB) together with Mach-Zehnder and Michelson-based interferometric techniques. The interferometric method provides a measurement of the phase step for several wavelengths, which characterizes the chromatic properties of the phase plate. Consequently, it is shown that the IWKB method allows us to design and characterize the phase plates in an easy and fast way.

  8. Free-space wavelength-multiplexed optical scanner demonstration.

    Science.gov (United States)

    Yaqoob, Zahid; Riza, Nabeel A

    2002-09-10

    Experimental demonstration of a no-moving-parts free-space wavelength-multiplexed optical scanner (W-MOS) is presented. With fast tunable lasers or optical filters and planar wavelength dispersive elements such as diffraction gratings, this microsecond-speed scanner enables large several-centimeter apertures for subdegree angular scans. The proposed W-MOS design incorporates a unique optical amplifier and variable optical attenuator combination that enables the calibration and modulation of the scanner response, leading to any desired scanned laser beam power shaping. The experimental setup uses a tunable laser centered at 1560 nm and a 600-grooves/mm blazed reflection grating to accomplish an angular scan of 12.92 degrees as the source is tuned over an 80-nm bandwidth. The values for calculated maximum optical beam divergance, required wavelength resolution, beam-pointing accuracy, and measured scanner insertion loss are 1.076 mrad, 0.172 nm, 0.06 mrad, and 4.88 dB, respectively.

  9. Linear Frequency Modulated Signals VS Orthogonal Frequency Division Multiplexing Signals for Synthetic Aperture Radar Systems

    Science.gov (United States)

    2014-06-01

    FREQUENCY MODULATED SIGNALS VS ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SIGNALS FOR SYNTHETIC APERTURE RADAR SYSTEMS by Sade A. Holder June...SIGNALS VS ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SIGNALS FOR SYNTHETIC APERTURE RADAR SYSTEMS 5. FUNDING NUMBERS 6. AUTHOR(S) Sade A. Holder 7...OFDM) signal versus a linear frequency modulated or chirp signal on simulated synthetic aperture radar (SAR) imagery. Various parameters of the

  10. High core count single-mode multicore fiber for dense space division multiplexing

    DEFF Research Database (Denmark)

    Aikawa, K.; Sasaki, Y.; Amma, Y.;

    2016-01-01

    Multicore fibers and few-mode fibers have the potential to realize dense-space-division multiplexing systems. Several dense-space-division multiplexing system transmission experiments over multicore fibers and few-mode fibers have been demonstrated so far. Multicore fibers, including recent resul...

  11. Demonstration of in-service wavelength division multiplexing optical-signal-to-noise ratio performance monitoring and operating guidelines for coherent data channels with different modulation formats and various baud rates.

    Science.gov (United States)

    Chitgarha, Mohammad Reza; Khaleghi, Salman; Daab, Wajih; Almaiman, Ahmed; Ziyadi, Morteza; Mohajerin-Ariaei, Amirhossein; Rogawski, Devora; Tur, Moshe; Touch, Joseph D; Vusirikala, Vijay; Zhao, Wendy; Willner, Alan E

    2014-03-15

    We demonstrated a delay-line interferometer (DLI)-based, optical-signal-to-noise ratio (OSNR) monitoring scheme of 100  Gbit/s polarization multiplexed quadrature-phase-shift-keying (PM-QPSK) four-channel WDM at 50-GHz International Telecommunication Union (ITU) grid with data format transparency and baud rate tunability of the OSNR monitor by measuring the OSNR for a 200  Gbit/s PM-16-QAM (25-Gbaud) signal and a 200  Gbit/s PM-QPSK (50-Gbaud) signal. We also explored and studied different monitor parameters, including the shape of the filter spectrum, the bandwidth of the filter, DLI delay, and DLI phase-detuning to determine the design guidelines for a desired level of accuracy for the OSNR monitor in an optical network.

  12. Integrated cladding-pumped multicore few-mode erbium-doped fibre amplifier for space-division-multiplexed communications

    Science.gov (United States)

    Chen, H.; Jin, C.; Huang, B.; Fontaine, N. K.; Ryf, R.; Shang, K.; Grégoire, N.; Morency, S.; Essiambre, R.-J.; Li, G.; Messaddeq, Y.; Larochelle, S.

    2016-08-01

    Space-division multiplexing (SDM), whereby multiple spatial channels in multimode and multicore optical fibres are used to increase the total transmission capacity per fibre, is being investigated to avert a data capacity crunch and reduce the cost per transmitted bit. With the number of channels employed in SDM transmission experiments continuing to rise, there is a requirement for integrated SDM components that are scalable. Here, we demonstrate a cladding-pumped SDM erbium-doped fibre amplifier (EDFA) that consists of six uncoupled multimode erbium-doped cores. Each core supports three spatial modes, which enables the EDFA to amplify a total of 18 spatial channels (six cores × three modes) simultaneously with a single pump diode and a complexity similar to a single-mode EDFA. The amplifier delivers >20 dBm total output power per core and EDFA enables combined space-division and wavelength-division multiplexed transmission over multiple multimode fibre spans.

  13. Improved orthogonal frequency division multiplexing communications through advanced coding

    Science.gov (United States)

    Westra, Jeffrey; Patti, John

    2005-08-01

    Orthogonal Frequency Division Multiplexing (OFDM) is a communications technique that transmits a signal over multiple, evenly spaced, discrete frequency bands. OFDM offers some advantages over traditional, single-carrier modulation techniques, such as increased immunity to inter-symbol interference. For this reason OFDM is an attractive candidate for sensor network application; it has already been included in several standards, including Digital Audio Broadcast (DAB); digital television standards in Europe, Japan and Australia; asymmetric digital subscriber line (ASDL); and wireless local area networks (WLAN), specifically IEEE 802.11a. Many of these applications currently make use of a standard convolutional code with Viterbi decoding to perform forward error correction (FEC). Replacing such convolutional codes with advanced coding techniques using iterative decoding, such as Turbo codes, can substantially improve the performance of the OFDM communications link. This paper demonstrates such improvements using the 802.11a wireless LAN standard.

  14. Wavelength-multiplexed ghost imaging in time (Conference Presentation)

    Science.gov (United States)

    Ryczkowski, Piotr; Genty, Goëry; Barbier, Margaux; Friberg, Ari T.; Dudley, John M.

    2017-02-01

    Ghost imaging is an optical technique that produces the image of an object by correlating the total amount of light transmitted through the object with the random intensity pattern that the object is irradiated with. When the technique is used with incoherent light sources, characterized by random temporal intensity fluctuations, it requires recording a very large number of distinct realizations to obtain a faithful image reproduction. In order to significantly reduce the number of realizations, one can use pre-programmed known patterns, so-called computational ghost imaging. Recently, ghost imaging was transposed into the time-domain to image ultrafast varying waveforms. Here, we report on a novel proof-of-concept experiment of computational ghost imaging in the time domain using wavelength multiplexing. By encoding different time-varying intensity patterns onto separate wavelength channels, we can perform simultaneous measurement of multiple realizations. This allows us to perform ghost imaging in real-time, without the need of probing the time-varying object repeatedly. Specifically, we use a programmable spectral filter to encode a set of 32 Hadamard-like time-varying intensity patterns onto a broadband LED light source. An electro-optic intensity modulator driven by an electrical waveform is used to create the time-varying object to be measured. The object is then reconstructed "blindly" by correlating the time-averaged transmission of each wavelength channels with the digitized form of the time-varying Hadamard patterns that illuminate the object. The temporal resolution of the measurement is currently to 0.5 s limited by the speed at which the variable spectral filter can be manipulated.

  15. Synchronization, retiming and time-division multiplexing of an asynchronous 10 gigabit NRZ Ethernet packet to Terabit Ethernet

    DEFF Research Database (Denmark)

    Hu, Hao; Laguardia Areal, Janaina; Mulvad, Hans Christian Hansen

    2011-01-01

    time-division multiplexed with a serial 1.28 Tb/s signal including a vacant time slot, thus forming a 1.29 Tb/s time-division multiplexed serial signal. Error-free performance of synchronizing, retiming, time-division multiplexing to a Terabit data stream and finally demultiplexing back to 10 Gb...

  16. Engineered silicon ring resonator for wavelength multiplexed photon-pair generation

    CERN Document Server

    Mazeas, Florent; Bentivegna, Marco; Kaiser, Florian; Aktas, Djeylan; Zhang, Weiwei; Ramos, Carlos Alonso; Bin-Ngah, Lutfi-Arif; Lunghi, Tommaso; Picholle, Éric; Belabas-Plougonven, Nadia; Roux, Xavier Le; Cassan, Éric; Marris-Morini, Delphine; Vivien, Laurent; Sauder, Grégory; Labonté, Laurent; Tanzilli, Sébastien

    2016-01-01

    We report an efficient energy-time entangled photon-pair source based on four-wave mixing in a CMOS-compatible silicon photonics ring resonator. Thanks to suitable optimization, the source shows a large spectral brightness of 400 pairs of entangled photons /s/MHz for 500 {\\mu}W pump power. Additionally, the resonator has been engineered so as to generate a frequency comb structure compatible with standard telecom dense wavelength division multiplexers. We demonstrate high-purity energy-time entanglement, i.e., free of photonic noise, with near perfect raw visibilities (> 98%) between various channel pairs in the telecom C-band. Such a compact source stands as a path towards more complex quantum photonic circuits dedicated to quantum communication systems.

  17. A passive optical network based on optical code division multiplexing and time division multiple access technology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A passive optical network (PON) scheme based on optical code division multiplexing (OCDM) for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access (TDMA) technology to decrease the cost.This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network (OAN) with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance,and enhances flexibility and scalability of the system.

  18. 复用技术在空间光通信中的应用研究%Application of Division Multiplexing Technology in Space Optical Communication

    Institute of Scientific and Technical Information of China (English)

    王翔; 赵尚弘; 李勇军; 朱子行; 赵顾颢

    2011-01-01

    The division multiplexing technology, which can improve the capacity of the system by using the present instruments and mature technologies, has become an important technical method for high-speed space optical communication. From the viewpoint of increasing the speed of transmitting information, the recent progresses and basic principles of five kinds of division multiplexing technology are introduced, including polarization division multiplexing, wavelength division multiplexing, time division multiplexing, optical MIMO and orthogonal frequency division multiplexing. The advantages and disadvantages of each division multiplexing technology are analyzed. The analytical results indicate that the orthogonal frequency division multiplexing and optical MIMO is one of the effective methods for realizing the transmission of massive information.%复用技术能够利用现有的硬件设备和成熟技术,成倍地提高系统容量,已经成为高速空间光通信的重要技术手段.文章从提高信息传输速率的角度出发,研究了偏振复用、波分复用、时分复用、光MIMO以及正交频分复用五种复用技术在空间光通信应用的基本原理,并介绍了最新研究动态.对比分析了空间光通信中五种复用技术的优缺点,结果表明正交频分复用和光MIMO技术是实现空间光通信海量信息传输的有效途径之一,具有很大的发展潜力.

  19. Digital Frequency Domain Multiplexer for mm-Wavelength Telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Spieler, Helmuth G; Dobbs, Matt; Bissonnette, Eric; Spieler, Helmuth G.

    2007-07-23

    An FPGA based digital signal processing (DSP) system for biasing and reading out multiplexed bolometric detectors for mm-wavelength telescopes is presented. This readout system is being deployed for balloon-borne and ground based cosmology experiments with the primary goal of measuring the signature of inflation with the Cosmic Microwave Background Radiation. The system consists of analog superconducting electronics running at 250 mK and 4 K, coupled to digital room temperature backend electronics described here. The digital electronics perform the real time functionality with DSP algorithms implemented in firmware. A soft embedded processor provides all of the slow housekeeping control and communications. Each board in the system synthesizes multi-frequency combs of 8 to 32 carriers in the MHz band to bias the detectors. After the carriers have been modulated with the sky-signal by the detectors, the same boards digitize the comb directly. The carriers are mixed down to base-band and low pass filtered. The signal bandwidth of 0.050Hz-100 Hz places extreme requirements on stability and requires powerful filtering techniques to recover the sky-signal from the MHz carriers.

  20. Performance improvement of hybrid subcarrier multiplexing optical spectrum code division multiplexing system using spectral direct decoding detection technique

    Science.gov (United States)

    Sahbudin, R. K. Z.; Abdullah, M. K.; Mokhtar, M.

    2009-06-01

    This paper proposes a hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system for the purpose of combining the advantages of both techniques. Optical spectrum code division multiple-access (OSCDMA) is one of the multiplexing techniques that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty nature networks. On the other hand, subcarrier multiplexing (SCM) technique is able to enhance the channel data rate of OSCDMA systems. In this paper, a newly developed detection technique for the OSCDM called spectral direct decoding (SDD) detection technique is compared mathematically with the AND subtraction detection technique. The system utilizes a new unified code construction named KS (Khazani-Syed) code. The results characterizing the bit-error-rate (BER) show that SDD offers a significant improved performance at BER of 10 -9.

  1. Low DSP complexity mid-haul mode-division multiplexing links utilizing wideband modal dispersion compensated two-mode fibers

    Science.gov (United States)

    Diamantopoulos, N. P.; Nakazawa, M.; Yoshida, Y.; Maruta, A.; Maruyama, R.; Kuwaki, N.; Matsuo, S.; Kitayama, K.

    2015-11-01

    Mode-division multiplexing (MDM) over wavelength division multiplexed (WDM) networks is studied, particularly for the deployment of metro area networks (MAN) using two-mode fibers (TMF). Full C-band differential mode group delay (DMGD)-compensated TMF links are adopted for decreasing the computational complexity of real-time multiple-input multiple-output (MIMO) signal processing. The effect of modal crosstalk to the maximum delay spread of the channel is validated through numerical simulations. Finally, the 2×2 MIMO channel state information (CSI) of a 102.6-km DMGD-compensated TMF link is experimentally estimated for mode path provisioning based upon routing and mode assignment (RMA) in MDM networks. The results confirm close-to-zero total DMGD value over the entire C-band.

  2. Optical switching and detection of 640 Gbits/s optical time-division multiplexed data packets transmitted over 50 km of fiber

    DEFF Research Database (Denmark)

    Gomez-Agis, F.; Hu, Hao; Luo, J.

    2011-01-01

    We demonstrate 1 × 4 optical-packet switching with error-free transmission of 640 Gbits/s single-wavelength optical time-division multiplexed data packets including clock distribution and short pulse generation for optical time demultiplexing based on a cavityless pulse source. © 2011 Optical...

  3. Effects of pattern dependence on high-power polarization-division-multiplexing applications

    Institute of Scientific and Technical Information of China (English)

    Anlin Yi; Lianshan Yan; Bin Luo; Wei Pan; Jia Ye

    2012-01-01

    High-power polarization-division-multiplexing (PDM) systems or functional modules,such as self-phasemodulation (SPM)-based all-optical regenerators,cross-phase-modulation (XPM)-based wavelength convertors or format convertors,all-optical logical gate,and so on,may suffer from the effects of pattern dependence.Such effects are experimentally investigated using relative time delay variation between bit sequences with orthogonal polarization states in a 2 × 10.65 Gb/s high-power on-off keying (OOK) PDM system.Eye-diagram-based signal-to-noise ratio (SNR) and bandwidth of broadened spectrum are measured and compared.An eye-diagram-based SNR fluctuation of up to 4 dB may occur as the delay changes.

  4. A novel method of polarization state control for olarization division multiplexing system

    Institute of Scientific and Technical Information of China (English)

    Tiecheng Wang; Shoufeng Lan; Junfeng Jiang; Tiegen Liu

    2008-01-01

    We describe a new algorithm in a cost effective polarization division multiplexing (PDM) system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to demultiplex the signal multiplexed and improve it with a conjugated gradient algorithm. We experimentally resume the polarization state with a deviation under 5% and the power loss less than 20 dB which proves the feasibility of the polarization control algorithm in the new polarization multiplexing system.

  5. Test of mode-division multiplexing and demultiplexing in free-space with diffractive transformation optics

    OpenAIRE

    Ruffato, Gianluca; Massari, Michele; Parisi, Giuseppe; Romanato, Filippo

    2016-01-01

    In recent years, mode-division multiplexing (MDM) has been proposed as a promising solution in order to increase the information capacity of optical networks both in free-space and in optical fiber transmission. Here we present the design, fabrication and test of diffractive optical elements for mode-division multiplexing based on optical transformations in the visible range. Diffractive optics have been fabricated by means of 3D high-resolution electron beam lithography on polymethylmethacry...

  6. NG-PON2 Architecture Enabled by Heterogeneous Space Division Multiplexing with Distributed Light Source: A Proof-of-Concept Evaluation

    DEFF Research Database (Denmark)

    Asif, Rameez; Imran, Muhammad; Ye, Feihong

    2015-01-01

    We have numerically evaluated the next generation passive optical network stage-2 (NG-PON2) architecture based on heterogeneous space division multiplexing (SDM) and wavelength-division multiplexing (WDM). Error free transmission (BER of 10−9 ) is obtained for all the downstream (DS) and upstream...... (US) data tributaries, each carrying 40 Gbit/s data, over 20-km of 19-core multi-core fiber (MCF) and 6-spatial-mode fewmode fiber (FMF) without using multiple-input multiple-output (MIMO) digital signal processing (DSP), respectively....

  7. Topology Optimized Components for Mode- and Wavelength Division Multiplexing

    DEFF Research Database (Denmark)

    Frellsen, Louise Floor

    This thesis deals with the topic of passive integrated nanophotonic devices realized in silicon on insulator material. The project has been concerned with all the steps of the process: Design, fabrication and characterization. The focus has been on using the inverse design method topology...... optimization.The method has been employed extensively to obtain various nanophotonic components. One of the outcomes of the project has been the development of a solid understanding of the benefits and limitations of topology optimization. This thesis presents numerous designs that have been characterized both...... that topology optimization is a strong method for creating extremely compact devices, the small features do however mean that they are not yet possible to fabricate on a large scale. Complex device functionalities can be obtained. Building on previous work of simpler structures it is comparatively easy...

  8. Research on Raman Crosstalk in Broadband Wavelength Division Multiplexed Systems

    Institute of Scientific and Technical Information of China (English)

    XUE Fei; QIU Kun

    2004-01-01

    After a theoretical model is put forward on the base of accurate description of the Raman gain profile and the physical quantity,maximum Raman crosstalk(MRC),which quantificationally depicts the intensity of Raman crosstalk is defined.The influences of launch power,fiber effective core area,fiber nonlinear index,fiber length,channel number and channel interval on MRC are deduced.The result indicates that compared with low speed and narrowband optical fiber communication system,serious Raman crosstalk lies in high speed and broadband system,which impacts the performance of the system badly.The result is useful for forecasting Raman crosstalk in broadband and high speed optical fiber communication system.

  9. Few-mode fibers for mode division multiplexing transmission

    Science.gov (United States)

    Kubota, Hirokazu; Morioka, Toshio

    2012-01-01

    A study is presented of the fiber properties needed to achieve 10-mode multiplexing transmission. A combination of MIMO processing with optical LP mode separation is proposed to prevent the need for massive MIMO computation. The impact of mode crosstalk, differential mode delay, and the mode dependent loss of the few-mode fibers on mode multiplexing are discussed.

  10. Calculation of degenerate four-wave-mixing noise for chirped Gaussian pulse in dense-wavelength-division-multiplexed system%DWDM系统啁啾高斯脉冲简并四波混频噪声标准差的计算

    Institute of Scientific and Technical Information of China (English)

    杜建新

    2009-01-01

    假定入射脉冲为啁啾高斯脉冲,考虑到各信道内的比特模式及比特序列初始相位的随机性,得到此种情况下的强度调制直接检测(IM/DD)密集波分复用系统(DWDM)简并四波混频噪声标准差的半解析理论计算模型,这个理论模型同时考虑到各信道间的脉冲走离效应的影响,计算结果表明:除了群速度色散、信道间隔等是影响此种标准差的重要因素外,当高斯脉冲有较小的初始脉宽时,各信道比特序列的相对初始时延、初始啁啾参量都是重要的影响因素;初始脉宽较小时,色散效应导致的脉宽随距离的变化对这种标准差值的影响不能忽略.%The launched pulses for dense wavelength-division-multiplexing (DWDM) system with intensity modulated and direct-detection (IM/DD) scheme are assumed to be chirped Gaussian pulses. The pattern and initial phase of bit sequence in each channel are random. A statistical method is used to analyze these random quantities and a semi-analytic calculation model applied to evaluate the variance of degenerate four-wave-mixing (FWM) noise is obtained. The model also accounts for walk-off effect between channels. The results of calculation show that, to the value of deviation of degenerate FWM noise of chirped Gaussian pulse, not only the group velocity and channel separation are important, but also the initial delay of bit sequence of each channel and initial chirp of pulse are important in the case of small values of launched pulse width. It is also shown that, when the width of launched pulse is small, the change of pulse width with distance due to dispersion effect must be considered to avoid relative large error.

  11. λ-Selection Strategy in C+L Band 1-Pbit/s (448 WDM/19-Core/128 Gbit/s/channel) Flex-Grid Space Division Multiplexed Transmission

    DEFF Research Database (Denmark)

    Asif, Rameez; Ye, Feihong; Morioka, Toshio

    2015-01-01

    In this paper, an inter-core crosstalk based wavelength selection scheme has been proposed for flex-grid superchannels in space division multiplexed transmission. The two λ-selection strategies are categorized as: (a) aligned wavelength super-channels (Aλ-SCs), where all super-channels are placed...

  12. Mode-selective optical packet switching in mode-division multiplexing networks.

    Science.gov (United States)

    Diamantopoulos, N P; Hayashi, M; Yoshida, Y; Maruta, A; Maruyama, R; Kuwaki, N; Takenaga, K; Uemura, H; Matsuo, S; Kitayama, K

    2015-09-07

    A novel mode-selective optical packet switching, based on mode-multiplexers/demultiplexers and multi-port optical micro-electro-mechanical systems (MEMS) switches, has been proposed and experimentally demonstrated. The experimental demonstration was performed using the LP(01), LP(11a) and LP(11b) modes of a 30-km long mode-division multiplexed few-mode fiber link, utilizing 40 Gb/s, 16-QAM signals.

  13. 4 X 20 Gbit/s mode division multiplexing over free space using vector modes and a q-plate mode (de)multiplexer

    CERN Document Server

    Milione, Giovanni; Huang, Hao; Ren, Yongxiong; Xie, Guodong; Nguyen, Thien An; Karimi, Ebrahim; Marrucci, Lorenzo; Nolan, Daniel A; Alfano, Robert R; Willner, Alan E

    2014-01-01

    Vector modes are spatial modes that have spatially inhomogeneous states of polarization, such as, radial and azimuthal polarization. They can produce smaller spot sizes and stronger longitudinal polarization components upon focusing. As a result, they are used for many applications, including optical trapping and nanoscale imaging. In this work, vector modes are used to increase the information capacity of free space optical communication via the method of optical communication referred to as mode division multiplexing. A mode (de)multiplexer for vector modes based on a liquid crystal technology referred to as a q-plate is introduced. As a proof of principle, using the mode (de)multiplexer four vector modes each carrying a 20 Gbit/s quadrature phase shift keying signal on a single wavelength channel (~1550nm), comprising an aggregate 80 Gbit/s, were transmitted ~1m over the lab table with <-16.4 dB (<2%) mode crosstalk. Bit error rates for all vector modes were measured at the forward error correction t...

  14. An order of magnitude improvement in optical fiber bandwidth using spatial domain multiplexing/space division multiplexing (SDM) in conjunction with orbital angular momentum (OAM)

    Science.gov (United States)

    Murshid, Syed; Alanzi, Saud; Hridoy, Arnob; Lovell, Greg; Parhar, Gurinder; Chakravarty, Abhijit; Chowdhury, Bilas

    2014-09-01

    Spatial Domain Multiplexing/Space Division Multiplexing (SDM) can increase the bandwidth of existing and futuristic optical fibers by an order of magnitude or more. In the SDM technique, we launch multiple single mode pigtail laser sources of same wavelength into a carrier fiber at different angles. The launching angles decide the output of the carrier fiber by allocating separate spatial locations for each channel. Each channel follows a helical trajectory while traversing the length of the carrier fiber, thereby allowing spatial reuse of optical frequencies. In this endeavor we launch light from five different single mode pigtail laser sources at different angles (with respect to the axis of the carrier fiber) into the carrier fiber. Owing to helical propagation we get five distinct concentric donut shaped rings with negligible crosstalk at the output end of the fiber. These SDM channels also exhibit Orbital Angular Momentum (OAM), thereby adding an extra degree of photon freedom. We present the experimental data of five spatially multiplexed channels and compare them with simulated results to show that this technique can potentially improve the data capacity of optical fibers by an order of magnitude: A factor of five using SDM and another factor of two using OAM.

  15. Experimental Demonstration of Nonlinear Frequency Division Multiplexed Transmission

    CERN Document Server

    Aref, Vahid; Schuh, Karsten; Idler, Wilfried

    2015-01-01

    We experimentally demonstrate an NFDM optical system with modulation over nonlinear discrete spectrum. Particularly, each symbol carries 4-bits from multiplexing two eigenvalues modulated by QPSK constellation. We show a low error performance using NFT detection with 4Gbps rate over 640km.

  16. Multiple Access Scheme for Multi-Symbol Encapsulated Orthogonal Frequency Division Multiplexing

    Directory of Open Access Journals (Sweden)

    Biswajit Datta

    2011-11-01

    Full Text Available A new multiple access scheme using Multi-Symbol Encapsulated Orthogonal Frequency Division Multiplexing (MSE-OFDM is proposed. This is basically a time division multiple access (TDMA technique utilizing the MSE-OFDM. The Bit Error Rate (BER performance of the TDMA system using conventional OFDM is slightly better than that of the proposed system. This weakness is compensated as the proposed technique exhibits an improvement in bandwidth efficiency compared to the TDMA using conventional OFDM.

  17. [Fiber monitoring network of methane concentration based on space division multiplexing in coal mine].

    Science.gov (United States)

    Zhang, Ji-Long; Wang, Peng; Wang, Zhi-Bin; Li, Xiao; Wang, Zhi-Wen

    2010-06-01

    Methane explosion accidents occur frequently, and accurate and real-time detection and early warning of methane concentration are the effective means of preventing these accidents. The research was based on the spectrum absorption properties of methane, and a near-infrared tunable DFB laser diode of 1.65 microm wave band was used. With the mode-hopping features of laser diode, a differential absorption of double-wavelength and single-fiber optical sensor network was designed. Sixteen methane sensors were multiplexed in this system with space division multiple access technology and optical switch, and the key technologies of anti-dust in gas absorption cell were researched. All signals were gathered by the PCI data acquisition card, and information of each way was analyzed and displayed with virtual instrument. The results of experiment show that the method can reach the sensitivity of 0.05% even without using a phase-locked amplifier and the absorption light path is only 10 centimeters. Long-time accuracy and stability of all sensors could meet the practical demands, and the response time of each sensor was less than 1 seconds. With the replacement of lasers, the network can be used for the real-time detection of other gases.

  18. Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers

    Science.gov (United States)

    Gasulla, Ivana; Barrera, David; Hervás, Javier; Sales, Salvador

    2017-01-01

    The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multi-cavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability.

  19. Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers

    Science.gov (United States)

    Gasulla, Ivana; Barrera, David; Hervás, Javier; Sales, Salvador

    2017-01-01

    The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multi-cavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability. PMID:28134304

  20. Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers.

    Science.gov (United States)

    Gasulla, Ivana; Barrera, David; Hervás, Javier; Sales, Salvador

    2017-01-30

    The use of Spatial Division Multiplexing for Microwave Photonics signal processing is proposed and experimentally demonstrated, for the first time to our knowledge, based on the selective inscription of Bragg gratings in homogeneous multicore fibers. The fabricated devices behave as sampled true time delay elements for radiofrequency signals offering a wide range of operation possibilities within the same optical fiber. The key to processing flexibility comes from the implementation of novel multi-cavity configurations by inscribing a variety of different fiber Bragg gratings along the different cores of a 7-core fiber. This entails the development of the first fabrication method to inscribe high-quality gratings characterized by arbitrary frequency spectra and located in arbitrary longitudinal positions along the individual cores of a multicore fiber. Our work opens the way towards the development of unique compact fiber-based solutions that enable the implementation of a wide variety of 2D (spatial and wavelength diversity) signal processing functionalities that will be key in future fiber-wireless communications scenarios. We envisage that Microwave Photonics systems and networks will benefit from this technology in terms of compactness, operation versatility and performance stability.

  1. Interferometric characterization of few-mode fibers (FMF) for mode-division multiplexing (MDM)

    Science.gov (United States)

    Muliar, O.; Usuga, M. A.; Rottwitt, K.; Lægsgaard, J.

    2015-03-01

    The rapid growth of global data traffic demands the continuous search for new technologies and systems that could increase transmission capacity in optical links and recent experiments show that to do so, it is advantageous to explore new degrees of freedom such as polarization, wavelength or optical modes. Mode division multiplexing (MDM) appears in this context as a promising and viable solution for such capacity increase, since it utilizes multiple spatial modes of an optical fiber as individual communication channels for data transmission. In order to evaluate its performance, a MDM system requires advanced characterization methods with regard to the modal content of its photonics components and in particular of the fibers involved for data transmission. In this contribution we present a time-domain interferometric technique for a full modal characterization of few mode fibers (FMF), commonly used in a MDM scenario. This experimental technique requires the use of a Mach-Zehnder interferometer, where the reference's path length is controlled by an optical delay line. The interference between the output beams of reference and fiber under test (FUT) is recorded on a CCD camera and a careful evaluation of the resulting interferograms allows us to have full access to key parameters such as number of modes, modal weight, differential time delay between propagating modes and intensity profiles. In this work, we apply this simple and complete characterization method to the case of a short link with two optical modes propagating in a FMF, which illustrates its potential as a diagnostic tool for MDM systems.

  2. A Metaheuristic Scheduler for Time Division Multiplexed Network-on-Chip

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Bo; Sparsø, Jens; Pedersen, Mark Ruvald

    2014-01-01

    This paper presents a metaheuristic scheduler for inter-processor communication in multi-processor platforms using time division multiplexed (TDM) networks on chip (NOC). Compared to previous works, the scheduler handles a broader and more general class of platforms. Another contribution, which has...

  3. High-Spatial-Multiplicity Multicore Fibers for Future Dense Space-Division-Multiplexing Systems

    DEFF Research Database (Denmark)

    Matsuo, Shoichiro; Takenaga, Katsuhiro; Sasaki, Yusuke;

    2016-01-01

    Multicore fibers and few-mode fibers have potential application in realizing dense-space-division multiplexing systems. However, there are some tradeoff requirements for designing the fibers. In this paper, the tradeoff requirements such as spatial channel count, crosstalk, differential mode dela...

  4. Remote-Time Division Multiplexing of Bending Sensors Using a Broadband Light Source

    Directory of Open Access Journals (Sweden)

    Mikel Bravo

    2012-01-01

    Full Text Available This work experimentally demonstrates a remote sensing network which interrogates bending sensors using time-division multiplexing techniques and a broadband light source. The bending sensors are located 50 km away from the monitoring station. They are based on a simple tie displacement sensor and offer high-resolution measurements of displacement.

  5. A Statically Scheduled Time-Division-Multiplexed Network-on-Chip for Real-Time Systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Brandner, Florian; Sparsø, Jens

    2012-01-01

    This paper explores the design of a circuit-switched network-on-chip (NoC) based on time-division-multiplexing (TDM) for use in hard real-time systems. Previous work has primarily considered application-specific systems. The work presented here targets general-purpose hardware platforms. We...

  6. Compact wavelength add-drop multiplexers using Bragg gratings in coupled dielectric-loaded plasmonic waveguides

    CERN Document Server

    Biagi, Giulio; Radko, Ilya P; Rubahn, Horst-Günter; Pedersen, Kjeld; Bozhevolnyi, Sergey I

    2016-01-01

    We report a novel design of a compact wavelength add-drop multiplexer utilizing dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs). The DLSPPW-based configuration exploits routing properties of directional couplers and filtering abilities of Bragg gratings. We present practical realization of a 20-$\\mu$m-long device operating at telecom wavelengths that can reroute optical signals separated by approximately 70 nm in the wavelength band. We characterize the performance of the fabricated structures using scanning near-field optical microscopy as well as leakage-radiation microscopy and support our findings with numerical simulations.

  7. Simultaneous measurements of multiple parameters at elevated temperature using a frequency-division multiplexing scheme with tunable diode lasers.

    Science.gov (United States)

    Cai, Tingdong; Gao, Guangzhen; Liu, Ying

    2012-10-01

    A multiplexed diode-laser sensor system based on second harmonic detection of wavelength modulation spectroscopy (WMS) is developed for application at elevated temperatures with two near-infrared diode lasers multiplexed using a frequency-division multiplexing scheme. One laser is tuned over a H(2)O line pair near 7079.176 and 7079.855 cm(-1), and another laser is tuned over a pair of CO(2) and CO lines near 6361.250 and 6361.344 cm(-1). Temperature and concentrations of H(2)O, CO(2), and CO could be measured simultaneously by this system. In order to remove the need for calibration and correct for transmission variation due to beam steering, mechanical misalignments, soot, and windows fouling, the WMS-1f normalized 2f method is used. Demonstration experiments are conducted in a heated static cell. The precision of temperature and the concentrations for H(2)O, CO(2), and CO are found to be 1.57%, 3.87%, 3.01%, and 3.58%, respectively. These results illustrate the potential of this sensor for applications at high temperatures.

  8. Research on free-space optical communication based on time-division multiplexing

    Science.gov (United States)

    Wang, Dan; Zhou, Wenchao; Li, Zhen; Chen, Zhenqiang; Yin, Hao; Zhu, Siqi; Li, Anming

    2016-10-01

    This paper aims at designing and demonstrating a video and audio signals synchronous wireless transmission of free-space optical communication (FSO) system. Video and audio signals were modulated by the acousto-optical modulator (AOM). With the help of a designed circuit and programmable microcontroller, the system based on time division multiplexing (TDM) achieves the functions of signal de-multiplexing and wireless transmitting. Proved by experiments, the system meets the actual requirements with advantages of flexibility, practicality and low cost. And it provides an efficient scheme of synchronous wireless transmission of video and audio signals for monitoring system and TV access network.

  9. Monolithically mode division multiplexing photonic integrated circuit for large-capacity optical interconnection.

    Science.gov (United States)

    Chen, Guanyu; Yu, Yu; Zhang, Xinliang

    2016-08-01

    We propose and fabricate an on-chip mode division multiplexed (MDM) photonic interconnection system. Such a monolithically photonic integrated circuit (PIC) is composed of a grating coupler, two micro-ring modulators, mode multiplexer/demultiplexer, and two germanium photodetectors. The signals' generation, multiplexing, transmission, demultiplexing, and detection are successfully demonstrated on the same chip. Twenty Gb/s MDM signals are successfully processed with clear and open eye diagrams, validating the feasibility of the proposed circuit. The measured power penalties show a good performance of the MDM link. The proposed on-chip MDM system can be potentially used for large-capacity optical interconnection in future high-performance computers and big data centers.

  10. Enhanced hybrid asymmetrically clipped orthogonal frequency division multiplexing for optical wireless communications

    Science.gov (United States)

    Guan, Rui; Huang, Nuo; Wang, Jin-Yuan; Wang, Houyu; Chen, Ming

    2016-05-01

    This paper presents an enhanced hybrid asymmetrically clipped optical orthogonal frequency division multiplexing (EHACO-OFDM) scheme, which benefits from the simultaneous transmission of ACO-OFDM, pulse-amplitude-modulated discrete multitone modulation, and direct-current-biased optical orthogonal frequency division multiplexing (DCO-OFDM). Since the entire available bandwidth is utilized for data modulation, this scheme can achieve higher spectral efficiency than HACO-OFDM and ACO-OFDM. Moreover, as a smaller DC bias is introduced in our scheme, it is more power efficient than asymmetrically clipped DC-biased optical OFDM (ADO-OFDM) and DCO-OFDM. A modified receiver is also designed for this system, taking advantage of an iterative algorithm and a pairwise averaging. It has been shown by simulation that our three-path simultaneous transmission scheme can surpass the existing mixed OFDM-based schemes at high data rates. In addition, compared with the noniterative receiver, the modified receiver exhibits significant gains.

  11. Novel Equalization Techniques for Space Division Multiplexing Based on Stokes Space Update Rule

    Directory of Open Access Journals (Sweden)

    Francisco Javier Vaquero Caballero

    2017-02-01

    Full Text Available Space division multiplexing (SDM is a promising technology that aims to overcome the capacity crunch of optical communications. In this paper, we introduce the multiple-input multiple-output (MIMO Stokes Space Algorithm (SSA implemented in frequency domain, a novel equalization technique for space division multiplexing (SDM. Although different papers have been published about the SSA and its MIMO implementation, we provide for the first time an analysis of the of the convergence speed and frequency offset of the SSA compared to the least mean square (LMS. SSA algorithm can deal with higher frequency offsets and linewidths than LMS, being suitable for optical communications with higher phase noise. SSA does not need pre-compensation of frequency offset, which can be compensated after equalization without penalties. On the other hand, due to reduced convergence speed, SSA requires longer training sequences than LMS.

  12. Performance of Spatial Division Multiplexing MIMO with Frequency Domain Packet Scheduling

    DEFF Research Database (Denmark)

    Wei, Na; Pokhariyal, Akhilesh; Sørensen, Troels Bundgaard;

    2008-01-01

    This paper addresses the performance of Spatial Division Multiplexing (SDM) Multiple-input Multiple-output (MIMO) techniques together with Frequency Domain Packet Scheduling (FDPS) in both theory and practice. We start with a theoretical analysis under some ideal assumptions to derive the perform......This paper addresses the performance of Spatial Division Multiplexing (SDM) Multiple-input Multiple-output (MIMO) techniques together with Frequency Domain Packet Scheduling (FDPS) in both theory and practice. We start with a theoretical analysis under some ideal assumptions to derive...... is to investigate the impact of realistic factors on performance. Results confirm that the combination of SDM and FDPS can increase the spectral efficiency significantly, particularly in a micro-cell scenario, and up to 30%-60% gain is observed over 1x2 with FDPS depending on the traffic models considered. Finally...

  13. Simultaneous two-wavelength phase unwrapping using an external module for multiplexing off-axis holography.

    Science.gov (United States)

    Turko, Nir A; Shaked, Natan T

    2017-01-01

    We present a dual-wavelength external holographic microscopy module for quantitative phase imaging of 3D structures with extended thickness range. This is done by simultaneous acquisition of two off-axis interferograms, each at a different wavelength, and generation of a synthetic wavelength, which is larger than the sample optical thickness, allowing two-wavelength unwrapping. The simultaneous acquisition is carried out by using optical multiplexing of the two interferograms onto the camera, where each of them has orthogonal off-axis interference fringe direction in relation to the other one. We used the system to quantitatively image a 7.96 μm step target and 30.5 μm circular copper pillars.

  14. Code-division-multiplexed readout of large arrays of TES microcalorimeters

    Science.gov (United States)

    Morgan, K. M.; Alpert, B. K.; Bennett, D. A.; Denison, E. V.; Doriese, W. B.; Fowler, J. W.; Gard, J. D.; Hilton, G. C.; Irwin, K. D.; Joe, Y. I.; O'Neil, G. C.; Reintsema, C. D.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

    2016-09-01

    Code-division multiplexing (CDM) offers a path to reading out large arrays of transition edge sensor (TES) X-ray microcalorimeters with excellent energy and timing resolution. We demonstrate the readout of X-ray TESs with a 32-channel flux-summed code-division multiplexing circuit based on superconducting quantum interference device (SQUID) amplifiers. The best detector has energy resolution of 2.28 ± 0.12 eV FWHM at 5.9 keV and the array has mean energy resolution of 2.77 ± 0.02 eV over 30 working sensors. The readout channels are sampled sequentially at 160 ns/row, for an effective sampling rate of 5.12 μs/channel. The SQUID amplifiers have a measured flux noise of 0.17 μΦ0/√Hz (non-multiplexed, referred to the first stage SQUID). The multiplexed noise level and signal slew rate are sufficient to allow readout of more than 40 pixels per column, making CDM compatible with requirements outlined for future space missions. Additionally, because the modulated data from the 32 SQUID readout channels provide information on each X-ray event at the row rate, our CDM architecture allows determination of the arrival time of an X-ray event to within 275 ns FWHM with potential benefits in experiments that require detection of near-coincident events.

  15. Code Division Multiplexing Using AI Based Custom Constellation Scheme - Efficient Modulation for High Data rate Transmission

    Directory of Open Access Journals (Sweden)

    K.SESHADRI SASTRY,

    2010-06-01

    Full Text Available To achieve high bit rate in transmission over wireless channels frequency reuse is an encouraging concept . Rather than dividing allocated frequency spectrum into narrow band width channels , one for each user information is transmitted over a very wide frequency spectrum using the same carrier frequency within same frequency band . In this paper we propose code division multiplexing scheme in which Custom QAM modulator itself is used as code . The propose system is simulated and tested in Matlab 7.4.

  16. Mode-division multiplexed transmission with inline few-mode fiber amplifier.

    Science.gov (United States)

    Bai, Neng; Ip, Ezra; Huang, Yue-Kai; Mateo, Eduardo; Yaman, Fatih; Li, Ming-Jun; Bickham, Scott; Ten, Sergey; Liñares, Jesús; Montero, Carlos; Moreno, Vicente; Prieto, Xesús; Tse, Vincent; Man Chung, Kit; Lau, Alan Pak Tao; Tam, Hwa-Yaw; Lu, Chao; Luo, Yanhua; Peng, Gang-Ding; Li, Guifang; Wang, Ting

    2012-01-30

    We demonstrate mode-division multiplexed WDM transmission over 50-km of few-mode fiber using the fiber's LP01 and two degenerate LP11 modes. A few-mode EDFA is used to boost the power of the output signal before a few-mode coherent receiver. A 6×6 time-domain MIMO equalizer is used to recover the transmitted data. We also experimentally characterize the 50-km few-mode fiber and the few-mode EDFA.

  17. PAPR Reduction Techniques in Orthogonal Frequency Division Multiplexing (OFDM: A Review

    Directory of Open Access Journals (Sweden)

    Ravi Mohan

    2013-05-01

    Full Text Available High Peak-to-Average Power Ratio (PAPR is the one of the major drawback of the Orthogonal Frequency Division Multiplexing (OFDM transmitted signal. Many techniques have been proposed to mitigate the PAPR problem. Except for the signal distortion techniques such as clipping, peak windowing and companding and so on. The redundancy based PAPR reduction techniques include selective mapping, partial transmit sequence, tone reservation, tone injection and coding, etc information The undesired effects occurring to the distortion techniques can be alleviated with the penalty of the reduced transmission rates due to introduction of redundancy. In a turbo coded orthogonal frequency-division multiplexing (TCOFDM system, low peak-to-average power ratio (PAPR can be achieved by selective-mapping (SLM. OFDM consist of large number of independent subcarriers, as a result of which the amplitude of such a signal can have high peak values. The .Selected Mapping (SLM and turbo coding is one of the promising PAPR reduction techniques for OFDM. In a turbo coded orthogonal frequency-division multiplexing (TCOFDM system, low peak-to-average power ratio (PAPR can be achieved by selective-mapping (SLM

  18. Code-division multiplexing of superconducting transition-edge sensor arrays

    Science.gov (United States)

    Irwin, K. D.; Niemack, M. D.; Beyer, J.; Cho, H. M.; Doriese, W. B.; Hilton, G. C.; Reintsema, C. D.; Schmidt, D. R.; Ullom, J. N.; Vale, L. R.

    2010-03-01

    Multiplexed superconducting quantum interference device (SQUID) amplifiers have recently enabled the deployment of kilopixel arrays of superconducting transition-edge sensor (TES) detectors on a variety of receivers for astrophysics. Existing multiplexing techniques for TES arrays, however, have constraints due to aliasing of SQUID noise, the size of the required filtering elements, or the complexity of the room-temperature electronics that make it difficult to scale to much larger arrays. We have developed a Walsh code-division SQUID multiplexer that has the potential to enable the multiplexing of larger arrays or pixels with faster thermal response times. The multiplexer uses superconducting switches to modulate the polarity of coupling between N individual TES detectors and a single output SQUID channel. The polarities of the detector signals are switched in the pattern of an N × N Walsh matrix, so a frame composed of N orthogonal samples can be used to reconstruct the detector signals without degradation. We present an analysis of the circuit architecture and preliminary results.

  19. 640 Gbit/s optical time-division add-drop multiplexing in a non-linear optical loop mirror

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Galili, Michael; Oxenløwe, Leif Katsuo

    2009-01-01

    Error-free 640 Gbit/s all-optical time-division add-drop multiplexing is demonstrated using a non-linear optical loop mirror. Both the add- and drop operations are achieved simultaneously by switching.......Error-free 640 Gbit/s all-optical time-division add-drop multiplexing is demonstrated using a non-linear optical loop mirror. Both the add- and drop operations are achieved simultaneously by switching....

  20. Numerical investigation of polarization insensitive two-mode division (De)multiplexer based on an asymmetric directional coupler

    Science.gov (United States)

    Truong, Cao Dung; Trinh, M. Tuan; Dang, Hoai Bac; Nguyen, Van Tho

    2017-02-01

    We propose a polarization insensitive two-mode division (de)multiplexer based on a silicon-on-insulator platform operating with a broadband, low insertion and scattering loss, and small crosstalk. By using an asymmetric directional coupler, two-mode (de)multiplexing functions for both polarization TE and TM states can be realized by the numerical simulation. Simulated results using a three dimensional beam propagation method (3D-BPM) incorporated with an effective index method (EIM) show high performance of the device with an operation efficiency above 81.2% (i.e., insertion loss is less than 0.9 dB) in the range of ±5 nm around the central wavelength of 1550 nm. Fabrication tolerances also have proved suitability to current manufacture technologies for the planar waveguides. Besides a low scattering loss of the sidewall roughness and a little influence of dispersion, a small footprint can bring the device to applications of high bitrate and compact on-chip silicon photonic integrated circuits.

  1. Multi-element fiber technology for space-division multiplexing applications.

    Science.gov (United States)

    Jain, S; Rancaño, V J F; May-Smith, T C; Petropoulos, P; Sahu, J K; Richardson, D J

    2014-02-24

    A novel technological approach to space division multiplexing (SDM) based on the use of multiple individual fibers embedded in a common polymer coating material is presented, which is referred to as Multi-Element Fiber (MEF). The approach ensures ultralow crosstalk between spatial channels and allows for cost-effective ways of realizing multi-spatial channel amplification and signal multiplexing/demultiplexing. Both the fabrication and characterization of a passive 3-element MEF for data transmission, and an active 5-element erbium/ytterbium doped MEF for cladding-pumped optical amplification that uses one of the elements as an integrated pump delivery fiber is reported. Finally, both components were combined to emulate an optical fiber network comprising SDM transmission lines and amplifiers, and illustrate the compatibility of the approach with existing installed single-mode WDM fiber systems.

  2. Experimental demonstration of time- and mode-division multiplexed passive optical network

    Science.gov (United States)

    Ren, Fang; Li, Juhao; Tang, Ruizhi; Hu, Tao; Yu, Jinyi; Mo, Qi; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

    2017-07-01

    A time- and mode-division multiplexed passive optical network (TMDM-PON) architecture is proposed, in which each optical network unit (ONU) communicates with the optical line terminal (OLT) independently utilizing both different time slots and switched optical linearly polarized (LP) spatial modes. Combination of a mode multiplexer/demultiplexer (MUX/DEUX) and a simple N × 1 optical switch is employed to select the specific LP mode in each ONU. A mode-insensitive power splitter is used for signal broadcast/combination between OLT and ONUs. We theoretically propose a dynamic mode and time slot assignment scheme for TMDM-PON based on inter-ONU priority rating, in which the time delay and packet loss ratio's variation tendency are investigated by simulation. Moreover, we experimentally demonstrate 2-mode TMDM-PON transmission over 10 km FMF with 10-Gb/s on-off keying (OOK) signal and direct detection.

  3. Multiplexed single-mode wavelength-to-time mapping of multimode light

    Science.gov (United States)

    Chandrasekharan, Harikumar K.; Izdebski, Frauke; Gris-Sánchez, Itandehui; Krstajić, Nikola; Walker, Richard; Bridle, Helen L.; Dalgarno, Paul A.; MacPherson, William N.; Henderson, Robert K.; Birks, Tim A.; Thomson, Robert R.

    2017-01-01

    When an optical pulse propagates along an optical fibre, different wavelengths travel at different group velocities. As a result, wavelength information is converted into arrival-time information, a process known as wavelength-to-time mapping. This phenomenon is most cleanly observed using a single-mode fibre transmission line, where spatial mode dispersion is not present, but the use of such fibres restricts possible applications. Here we demonstrate that photonic lanterns based on tapered single-mode multicore fibres provide an efficient way to couple multimode light to an array of single-photon avalanche detectors, each of which has its own time-to-digital converter for time-correlated single-photon counting. Exploiting this capability, we demonstrate the multiplexed single-mode wavelength-to-time mapping of multimode light using a multicore fibre photonic lantern with 121 single-mode cores, coupled to 121 detectors on a 32 × 32 detector array. This work paves the way to efficient multimode wavelength-to-time mapping systems with the spectral performance of single-mode systems.

  4. High sensitivity measurement of NO, NO2 and NH3 using MIR-QCL and time division multiplexing WMS technology

    Science.gov (United States)

    Chen, Xiang; Yang, Chenguang; Hu, Mai; Xu, Zhenyu; Fan, Xueli; Wei, Min; Yao, Lu; He, Yabai; Kan, Ruifeng

    2016-10-01

    A compact system based on mid-infrared quantum cascade laser (QCL) operated in room temperature was developed for the simultaneous monitoring of NO, NO2 and NH3 in the air. Laser beams of three QCLs with central wavelength located at 1900 cm-1, 1600 cm-1, 1103.4 cm-1 were coupled to pass through the 60m long gas cell together. With the technology of time division multiplexing, wavelength modulation spectroscopy (WMS) signals of three lasers can be detected at adjacent scan process. The real-time second harmonic analysis was implemented to achieve simultaneous detection of NO, NO2 and NH3. A minimum detection limit (MDL) of 0.2ppb for NO, 0.12ppb for NO2 and 0.1ppb for NH3 with an optimum integration time around 100 seconds can be achieved for this setup. An ambient monitoring of three gasses during 5 hours was performed to inspect the local air quality.

  5. Interfacing Hardware Accelerators to a Time-Division Multiplexing Network-on-Chip

    DEFF Research Database (Denmark)

    Pezzarossa, Luca; Sørensen, Rasmus Bo; Schoeberl, Martin

    2015-01-01

    This paper addresses the integration of stateless hardware accelerators into time-predictable multi-core platforms based on time-division multiplexing networks-on-chip. Stateless hardware accelerators, like floating-point units, are typically attached as co-processors to individual processors in ...... implementation. The design evaluation is carried out using the open source T-CREST multi-core platform implemented on an Altera Cyclone IV FPGA. The size of the proposed design, including a floating-point accelerator, is about two-thirds of a processor....

  6. Mode-Dependent Loss and Gain: Statistics and Effect on Mode-Division Multiplexing

    CERN Document Server

    Ho, Keang-Po

    2011-01-01

    In multimode fiber transmission systems, mode-dependent loss and gain (collectively referred to as MDL) pose fundamental performance limitations. In the regime of strong mode coupling, the statistics of MDL (expressed in decibels or log power gain units) can be described by the eigenvalue distribution of zero-trace Gaussian unitary ensemble in the small-MDL region that is expected to be of interest for practical long-haul transmission. Information-theoretic channel capacities of mode-division-multiplexed systems in the presence of MDL are studied, including average and outage capacities, with and without channel state information.

  7. Fabrication and characterization of ion-exchanged glass binary phase plates for mode-division multiplexing

    Science.gov (United States)

    Montero, Carlos; Moreno, Vicente; Prieto-Blanco, Xesús; Mateo, Eduardo F.; Ip, Ezra; Liñares, Jesús

    2012-01-01

    In response to ever growing data traffic, significant efforts are being made to increase optical network capacity. One promising candidate is mode-division multiplexing (MDM) in few-mode fibers, which uses space as a new information-bearing dimension. A fundamental element for MDM is a modal transformer. Modal transformation can be implemented in a free-space basis by using multi-region phase plates. In this work we present the design, fabrication and characterization of monolithic binary phase plates by highly-uniform Ag+/Na+ ion-exchange in glass. Diffracted optical field intensities have been measured and high quality mode transformation has been confirmed.

  8. Argo: A Time-Elastic Time-Division-Multiplexed NOC using Asynchronous Routers

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens

    2014-01-01

    In this paper we explore the use of asynchronous routers in a time-division-multiplexed (TDM) network-on-chip (NOC), Argo, that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs...... are either synchronous or mesochronous. We use asynchronous routers to achieve a simpler, smaller, and more robust, self-timed design. Our design exploits the fact that pipelined asynchronous circuits also behave as ripple FIFOs. Thus, it avoids the need for explicit synchronization FIFOs between the routers...

  9. Weighted interframe averaging-based channel estimation for orthogonal frequency division multiplexing passive optical network

    Science.gov (United States)

    Lin, Bangjiang; Li, Yiwei; Zhang, Shihao; Tang, Xuan

    2015-10-01

    Weighted interframe averaging (WIFA)-based channel estimation (CE) is presented for orthogonal frequency division multiplexing passive optical network (OFDM-PON), in which the CE results of the adjacent frames are directly averaged to increase the estimation accuracy. The effectiveness of WIFA combined with conventional least square, intrasymbol frequency-domain averaging, and minimum mean square error, respectively, is demonstrated through 26.7-km standard single-mode fiber transmission. The experimental results show that the WIFA method with low complexity can significantly enhance transmission performance of OFDM-PON.

  10. Wavelet packet transform-based optical orthogonal frequency-division multiplexing transmission using direct detection

    Science.gov (United States)

    Zhang, Hongbo; Yi, Xingwen; Chen, Lei; Zhang, Jing; Deng, Mingliang; Qiu, Kun

    2012-10-01

    As an alternate to fast Fourier transform-based orthogonal frequency-division multiplexing (OFDM), wavelet packet transform (WPT)-based OFDM (WPT-OFDM) does not require cyclic prefix to avoid inter-symbol-interference. The wavelet has many varieties and therefore, it can provide more freedom for system design to suit different applications. We propose a real-valued WPT-OFDM that uses intensity modulation/direct detection. We also conduct an experiment to verify its performance through a 75-km standard single-mode fiber.

  11. A Metaheuristic Scheduler for Time Division Multiplexed Network-on-Chip

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Bo; Sparsø, Jens; Pedersen, Mark Ruvald

    This report presents a metaheuristic scheduler for inter-processor communication in multi-core platforms using time division multiplexed (TDM) networks on chip (NOC). Input to the scheduler is a specification of the target multi-core platform and a specification of the application. Compared...... that this is possible with only negligible impact on the schedule period. We evaluate the scheduler with seven different applications from the MCSL NOC benchmark suite. We observe that the metaheuristics perform better than the greedy solution. In the special case of all-to-all communication with equal bandwidths...

  12. Dynamic Time Multiplexing Fabrication of Holographic Polymer Dispersed Liquid Crystals for Increased Wavelength Sensitivity

    Science.gov (United States)

    Fontecchio, Adam K. (Inventor); Rai, Kashma (Inventor)

    2017-01-01

    Described herein is a new holographic polymer dispersed liquid crystal (HPDLC) medium with broadband reflective properties, and a new technique for fabrication of broadband HPDLC mediums. The new technique involves dynamic variation of the holography setup during HPDLC formation, enabling the broadening of the HPDLC medium's wavelength response. Dynamic variation of the holography setup may include the rotation and/or translation of one or more motorized stages, allowing for time and spatial, or angular, multiplexing through variation of the incident angles of one or more laser beams on a pre-polymer mixture during manufacture. An HPDLC medium manufactured using these techniques exhibits improved optical response by reflecting a broadband spectrum of wavelengths. A new broadband holographic polymer dispersed liquid crystal thin film polymeric mirror stack with electrically-switchable beam steering capability is disclosed. XXXX Described herein is a new holographic polymer dispersed liquid crystal (HPDLC) medium with broadband reflective properties, and a new technique for fabrication of broadband 10 HPDLC mediums. The new technique involves dynamic variation of the holography setup during HPDLC formation, enabling the broadening of the HPDLC medium's wavelength response. Dynamic variation of the holography setup may include the rotation and/or translation of one or more 15 motorized stages, allowing for time and spatial, or angular, multiplexing through variation of the incident angles of one or more laser beams on a pre-polymer mixture during manufacture. An HPDLC medium manufactured using these techniques exhibits improved optical response by reflecting 20 a broadband spectrum of wavelengths. A new broadband holographic polymer dispersed liquid crystal thin film polymeric mirror stack with electrically switchable beam steering capability is disclosed.

  13. Hybrid charge division multiplexing method for silicon photomultiplier based PET detectors

    Science.gov (United States)

    Park, Haewook; Ko, Guen Bae; Lee, Jae Sung

    2017-06-01

    Silicon photomultiplier (SiPM) is widely utilized in various positron emission tomography (PET) detectors and systems. However, the individual recording of SiPM output signals is still challenging owing to the high granularity of the SiPM; thus, charge division multiplexing is commonly used in PET detectors. Resistive charge division method is well established for reducing the number of output channels in conventional multi-channel photosensors, but it degrades the timing performance of SiPM-based PET detectors by yielding a large resistor-capacitor (RC) constant. Capacitive charge division method, on the other hand, yields a small RC constant and provides a faster timing response than the resistive method, but it suffers from an output signal undershoot. Therefore, in this study, we propose a hybrid charge division method which can be implemented by cascading the parallel combination of a resistor and a capacitor throughout the multiplexing network. In order to compare the performance of the proposed method with the conventional methods, a 16-channel Hamamatsu SiPM (S11064-050P) was coupled with a 4  ×  4 LGSO crystal block (3  ×  3  ×  20 mm3) and a 9  ×  9 LYSO crystal block (1.2  ×  1.2  ×  10 mm3). In addition, we tested a time-over-threshold (TOT) readout using the digitized position signals to further demonstrate the feasibility of the time-based readout of multiplexed signals based on the proposed method. The results indicated that the proposed method exhibited good energy and timing performance, thus inheriting only the advantages of conventional resistive and capacitive methods. Moreover, the proposed method showed excellent pulse shape uniformity that does not depend on the position of the interacted crystal. Accordingly, we can conclude that the hybrid charge division method is useful for effectively reducing the number of output channels of the SiPM array.

  14. PLC-based mode multi/demultiplexers for mode division multiplexing

    Science.gov (United States)

    Saitoh, Kunimasa; Hanzawa, Nobutomo; Sakamoto, Taiji; Fujisawa, Takeshi; Yamashita, Yoko; Matsui, Takashi; Tsujikawa, Kyozo; Nakajima, Kazuhide

    2017-02-01

    Recently developed PLC-based mode multi/demultiplexers (MUX/DEMUXs) for mode division multiplexing (MDM) transmission are reviewed. We firstly show the operation principle and basic characteristics of PLC-based MUX/DEMUXs with an asymmetric directional coupler (ADC). We then demonstrate the 3-mode (2LP-mode) multiplexing of the LP01, LP11a, and LP11b modes by using fabricated PLC-based mode MUX/DEMUX on one chip. In order to excite LP11b mode in the same plane, a PLC-based LP11 mode rotator is introduced. Finally, we show the PLC-based 6-mode (4LP-mode) MUX/DEMUX with a uniform height by using ADCs, LP11 mode rotators, and tapered waveguides. It is shown that the LP21a mode can be excited from the LP11b mode by using ADC, and the two nearly degenerated LP21b and LP02 modes can be (de)multiplexed separately by using tapered mode converter from E13 (E31) mode to LP21b (LP02) mode.

  15. Developments in Time-Division Multiplexing of X-ray Transition-Edge Sensors

    Science.gov (United States)

    Doriese, W. B.; Morgan, K. M.; Bennett, D. A.; Denison, E. V.; Fitzgerald, C. P.; Fowler, J. W.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Irwin, K. D.; Joe, Y. I.; Mates, J. A. B.; O'Neil, G. C.; Reintsema, C. D.; Robbins, N. O.; Schmidt, D. R.; Swetz, D. S.; Tatsuno, H.; Vale, L. R.; Ullom, J. N.

    2016-07-01

    Time-division multiplexing (TDM) is a mature scheme for the readout of arrays of transition-edge sensors (TESs). TDM is based on superconducting-quantum-interference-device (SQUID) current amplifiers. Multiple spectrometers based on gamma-ray and X-ray microcalorimeters have been operated with TDM readout, each at the scale of 200 sensors per spectrometer, as have several astronomical cameras with thousands of sub-mm or microwave bolometers. Here we present the details of two different versions of our TDM system designed to read out X-ray TESs. The first has been field-deployed in two 160-sensor (8 columns × 20 rows) spectrometers and four 240-sensor (8 columns × 30 rows) spectrometers. It has a three-SQUID-stage architecture, switches rows every 320 ns, and has total readout noise of 0.41 μ Φ 0 / surd Hz. The second, which is presently under development, has a two-SQUID-stage architecture, switches rows every 160 ns, and has total readout noise of 0.19 μ Φ 0 / surd Hz. Both quoted noise values are non-multiplexed and referred to the first-stage SQUID. In a demonstration of this new architecture, a multiplexed 1-column × 32-row array of NIST TESs achieved average energy resolution of 2.55± 0.01 eV at 6 keV.

  16. Quantification of MDL-induced signal degradation in MIMO-OFDM mode-division multiplexing systems.

    Science.gov (United States)

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

    2016-08-22

    Mode-division multiplexing (MDM) transmission over few-mode optical fiber has emerged as a promising technology to enhance transmission capacity, in which multiple-input-multiple-output (MIMO) digital signal processing (DSP) after coherent detection is used to demultiplex the signals. Compared with conventional single-mode systems, MIMO-MDM systems suffer non-recoverable signal degradation induced by mode-dependent loss (MDL). In this paper, the MDL-induced signal degradation in orthogonal-frequency-division-multiplexing (OFDM) MDM systems is theoretically quantified in terms of mode-average error vector magnitude (EVM) through frequency domain norm analysis. A novel scalar MDL metric is proposed considering the probability distribution of the practical MDM input signals, and a closed-form expression for EVM measured after zero-force (ZF) MIMO equalization is derived. Simulation results show that the EVM estimations utilizing the novel MDL metric remain unbiased for unrepeated links. For a 6 × 100 km 20-mode MDM transmission system, the estimation accuracy is improved by more than 90% compared with that utilizing traditional condition number (CN) based MDL metric. The proposed MDL metric can be used to predict the MDL-induced SNR penalty in a theoretical manner, which will be beneficial for the design of practical MIMO-MDM systems.

  17. A Study of the Key Techniques of High-Speed Optical Time Division Multiplexing Systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Several key techniques in high-speed optical time division multiplexing (OTDM) systems, including the generation and compression of gain-switched picosecond optical pulses, the all optical demultiplexer based on a nonlinear optical loop mirror (NOLM), terahertz optical asymmetric demultiplexer (TOAD) and the electroabsorption modulator in OTDM systems, are studied in this dissertation. The gain-switching characteristics and the nonlinear dynamics of a semiconductor laser are investigated by solving its single-mode rate equations numerically, highlighting the dependence of the pulse width and the peak power of a gain-switched pulse on the parameters such as the differential gain and the photon lifetime, and the effects of the DC bias current and the modulation current of the laser on the pulse width and the spectral width of the gain-switched pulse. The two-dimensional bifurcation diagram is computed in a large modulation current and modulation frequency range, and it is found that the low-frequency period doubling (multipling) and chaos region are not closed fully and outspread to the high modulation current direction with a narrow modulation frequency region. In addition, a new clock recovery scheme employing the period multipling is proposed. Besides compressing the gain-switched laser diode pulse can be compressed to 6.9ps by using this DILM compressor, and such a short pulse completely satisfies the requirement for a 40 Gbit/s optical time division multiplexing (OTDM) system.

  18. Super-channel oriented routing, spectrum and core assignment under crosstalk limit in spatial division multiplexing elastic optical networks

    Science.gov (United States)

    Zhao, Yongli; Zhu, Ye; Wang, Chunhui; Yu, Xiaosong; Liu, Chuan; Liu, Binglin; Zhang, Jie

    2017-07-01

    With the capacity increasing in optical networks enabled by spatial division multiplexing (SDM) technology, spatial division multiplexing elastic optical networks (SDM-EONs) attract much attention from both academic and industry. Super-channel is an important type of service provisioning in SDM-EONs. This paper focuses on the issue of super-channel construction in SDM-EONs. Mixed super-channel oriented routing, spectrum and core assignment (MS-RSCA) algorithm is proposed in SDM-EONs considering inter-core crosstalk. Simulation results show that MS-RSCA can improve spectrum resource utilization and reduce blocking probability significantly compared with the baseline RSCA algorithms.

  19. Multiplexed Single-Mode Wavelength-to-Time Mapping of Multimode Light

    CERN Document Server

    Chandrasekharan, Harikumar K; Gris-Sánchez, Itandehui; Krstajić, Nikola; Walker, Richard; Bridle, Helen L; Dalgarno, Paul A; MacPherson, William N; Henderson, Robert K; Birks, Tim A; Thomson, Robert R

    2016-01-01

    We demonstrate that photonic lanterns based on tapered multicore fibres provide an efficient way to couple multimode states of light to a two-dimensional array of Single-Photon Avalanche Detectors (SPADs), each of which has its own Time-to-Digital Converter (TDC) for Time-Correlated Single-Photon-Counting (TCSPC). Exploiting this capability, we demonstrate multiplexed single-mode wavelength-to-time conversion of multimode states of light using a multicore-fibre photonic lantern with 121 single-mode cores, coupled in a one-to-one fashion to 121 SPADS on a 32 $\\times$ 32 pixel CMOS SPAD array. The application of photonic lanterns for coupling multimode light to SPAD arrays in this manner may find wide-ranging applications in areas such as Raman spectroscopy, coherent LIDAR and quantum optics.

  20. Advanced Spatial-Division Multiplexed Measurement Systems Propositions—From Telecommunication to Sensing Applications: A Review

    Science.gov (United States)

    Weng, Yi; Ip, Ezra; Pan, Zhongqi; Wang, Ting

    2016-01-01

    The concepts of spatial-division multiplexing (SDM) technology were first proposed in the telecommunications industry as an indispensable solution to reduce the cost-per-bit of optical fiber transmission. Recently, such spatial channels and modes have been applied in optical sensing applications where the returned echo is analyzed for the collection of essential environmental information. The key advantages of implementing SDM techniques in optical measurement systems include the multi-parameter discriminative capability and accuracy improvement. In this paper, to help readers without a telecommunication background better understand how the SDM-based sensing systems can be incorporated, the crucial components of SDM techniques, such as laser beam shaping, mode generation and conversion, multimode or multicore elements using special fibers and multiplexers are introduced, along with the recent developments in SDM amplifiers, opto-electronic sources and detection units of sensing systems. The examples of SDM-based sensing systems not only include Brillouin optical time-domain reflectometry or Brillouin optical time-domain analysis (BOTDR/BOTDA) using few-mode fibers (FMF) and the multicore fiber (MCF) based integrated fiber Bragg grating (FBG) sensors, but also involve the widely used components with their whole information used in the full multimode constructions, such as the whispering gallery modes for fiber profiling and chemical species measurements, the screw/twisted modes for examining water quality, as well as the optical beam shaping to improve cantilever deflection measurements. Besides, the various applications of SDM sensors, the cost efficiency issue, as well as how these complex mode multiplexing techniques might improve the standard fiber-optic sensor approaches using single-mode fibers (SMF) and photonic crystal fibers (PCF) have also been summarized. Finally, we conclude with a prospective outlook for the opportunities and challenges of SDM

  1. Advanced Spatial-Division Multiplexed Measurement Systems Propositions-From Telecommunication to Sensing Applications: A Review.

    Science.gov (United States)

    Weng, Yi; Ip, Ezra; Pan, Zhongqi; Wang, Ting

    2016-08-30

    The concepts of spatial-division multiplexing (SDM) technology were first proposed in the telecommunications industry as an indispensable solution to reduce the cost-per-bit of optical fiber transmission. Recently, such spatial channels and modes have been applied in optical sensing applications where the returned echo is analyzed for the collection of essential environmental information. The key advantages of implementing SDM techniques in optical measurement systems include the multi-parameter discriminative capability and accuracy improvement. In this paper, to help readers without a telecommunication background better understand how the SDM-based sensing systems can be incorporated, the crucial components of SDM techniques, such as laser beam shaping, mode generation and conversion, multimode or multicore elements using special fibers and multiplexers are introduced, along with the recent developments in SDM amplifiers, opto-electronic sources and detection units of sensing systems. The examples of SDM-based sensing systems not only include Brillouin optical time-domain reflectometry or Brillouin optical time-domain analysis (BOTDR/BOTDA) using few-mode fibers (FMF) and the multicore fiber (MCF) based integrated fiber Bragg grating (FBG) sensors, but also involve the widely used components with their whole information used in the full multimode constructions, such as the whispering gallery modes for fiber profiling and chemical species measurements, the screw/twisted modes for examining water quality, as well as the optical beam shaping to improve cantilever deflection measurements. Besides, the various applications of SDM sensors, the cost efficiency issue, as well as how these complex mode multiplexing techniques might improve the standard fiber-optic sensor approaches using single-mode fibers (SMF) and photonic crystal fibers (PCF) have also been summarized. Finally, we conclude with a prospective outlook for the opportunities and challenges of SDM

  2. Advanced Spatial-Division Multiplexed Measurement Systems Propositions—From Telecommunication to Sensing Applications: A Review

    Directory of Open Access Journals (Sweden)

    Yi Weng

    2016-08-01

    Full Text Available The concepts of spatial-division multiplexing (SDM technology were first proposed in the telecommunications industry as an indispensable solution to reduce the cost-per-bit of optical fiber transmission. Recently, such spatial channels and modes have been applied in optical sensing applications where the returned echo is analyzed for the collection of essential environmental information. The key advantages of implementing SDM techniques in optical measurement systems include the multi-parameter discriminative capability and accuracy improvement. In this paper, to help readers without a telecommunication background better understand how the SDM-based sensing systems can be incorporated, the crucial components of SDM techniques, such as laser beam shaping, mode generation and conversion, multimode or multicore elements using special fibers and multiplexers are introduced, along with the recent developments in SDM amplifiers, opto-electronic sources and detection units of sensing systems. The examples of SDM-based sensing systems not only include Brillouin optical time-domain reflectometry or Brillouin optical time-domain analysis (BOTDR/BOTDA using few-mode fibers (FMF and the multicore fiber (MCF based integrated fiber Bragg grating (FBG sensors, but also involve the widely used components with their whole information used in the full multimode constructions, such as the whispering gallery modes for fiber profiling and chemical species measurements, the screw/twisted modes for examining water quality, as well as the optical beam shaping to improve cantilever deflection measurements. Besides, the various applications of SDM sensors, the cost efficiency issue, as well as how these complex mode multiplexing techniques might improve the standard fiber-optic sensor approaches using single-mode fibers (SMF and photonic crystal fibers (PCF have also been summarized. Finally, we conclude with a prospective outlook for the opportunities and challenges of

  3. Snapping shrimp noise mitigation based on statistical detection in underwater acoustic orthogonal frequency division multiplexing systems

    Science.gov (United States)

    Kim, Hyeonsu; Seo, Jongpil; Ahn, Jongmin; Chung, Jaehak

    2017-07-01

    We propose a mitigation scheme for snapping shrimp noise when it corrupts an orthogonal frequency division multiplexing (OFDM) signal in underwater acoustic communication systems. The OFDM signal distorted by the snapping shrimp noise is filtered by a band-stop filter. The snapping shrimp noises in the filtered signal are detected by a detector with a constant false alarm rate whose threshold is derived theoretically from the statistics of the background noise. The detected signals are reconstructed by a simple reconstruction method. The proposed scheme has a higher detection capability and a lower mean square error of the channel estimation for simulated data and a lower bit error rate for practical ocean OFDM data collected in northern East China Sea than the conventional noise-mitigating methods.

  4. Signal generation and processing at 100 Gb/s based on optical time division multiplexing

    Institute of Scientific and Technical Information of China (English)

    Li HUO; Qiang WANG; Yanfei XING; Caiyun LOU

    2013-01-01

    In this paper, we review our recent works in 100 Gb/s signal generation and processing. A high-speed 100 Gb/s system with on-off keying (0OK) modulation format is implemented by using optical time division multiplexing (OTDM) method. As modifications of this system, simultaneous multicolor optical signal generation and 100Gb/s return-to-zero (RZ)-to-non-return-to-zero (NRZ) format conversion are presented. We also demonstrate basic all-optical signal processing functions of 100 GHz clock recovery and 100 Gb/s all-optical 2R generation based on semiconductor optical amplifiers (SOAs).

  5. Experimental investigation of buried landmine detection using time division multiplexing of multibeam laser Doppler vibrometer channels

    Science.gov (United States)

    Burgett, Richard; Aranchuk, Vyacheslav; Aranchuk, Ina

    2012-06-01

    Producing vibration images of buried landmines using a multi-beam laser Doppler vibrometer (MB-LDV) operating from a stationary platform have been accomplished in the past. Detection from a continuously moving platform can reduce the time of detection compared to stop-and-stare measurement. However, there is a speed limitation, imposed by the required spatial and frequency resolution. NCPA proposed a concept of time division multiplexing (TDM) of laser beams of a MB-LDV to overcome that speed limitation. The system, based on 16-beam MB-LDV, has been built and experimentally tested at an Army test facility. Vibration velocity profiles of buried mines have been obtained at different system speeds. Algorithms for speckle noise reduction in continuously moving MB-LDV signals have been developed and explored. The results of the current data collection, recent past data collection as well as the results of the effectiveness of speckle noise reduction techniques are presented.

  6. Router Designs for an Asynchronous Time-Division-Multiplexed Network-on-Chip

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens; Sørensen, Rasmus Bo

    2013-01-01

    In this paper we explore the design of an asynchronous router for a time-division-multiplexed (TDM) network-on-chip (NOC) that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs are either...... synchronous or mesochronous, but both approaches have their limitations: a globally synchronous NOC is no longer feasible in today's sub micron technologies and a mesochronous NOC requires special FIFO-based synchronizers in all input ports of all routers in order to accommodate for clock phase differences....... This adds hardware complexity and increases area and power consumption. We propose to use asynchronous routers in order to achieve a simpler, more robust and globally-asynchronous NOC, and this represents an unexplored point in the design space. The paper presents a range of alternative router designs. All...

  7. Diversity Analysis of Bit-Interleaved Coded Multiple Beamforming with Orthogonal Frequency Division Multiplexing

    CERN Document Server

    Li, Boyu

    2011-01-01

    Beamforming techniques employing Singular Value Decomposition (SVD) are commonly used in Multi-Input Multi-Output (MIMO) wireless communication systems. For frequency selective channels, Bit-Interleaved Coded Multiple Beamforming with Orthogonal Frequency Division Multiplexing (BICMB-OFDM) can be applied to achieve both spatial diversity and multipath diversity. However, the diversity analysis of BICMB-OFDM is a challenging problem because of its complicated system structure. In this paper, the diversity of BICMB-OFDM is investigated with the consideration of the correlation among subcarrier channels. Based on the analysis, the maximum achievable diversity is derived. Then, a full diversity condition RcSL<=1 is proved, where Rc, S, and L are the code rate, the number of parallel streams, and the number of channel taps, respectively. However, with correlation, the actual diversity is degraded compared to its maximum achievable value. Therefore, two strategies are discussed to combat the diversity degradatio...

  8. Performance analysis of modified Asymmetrically-Clipped Optical Orthogonal Frequency-Division Multiplexing systems

    Science.gov (United States)

    Mohamed, Salma D.; Shalaby, Hossam M. H.; Andonovic, Ivan; Aly, Moustafa H.

    2016-12-01

    A modification to the Asymmetrically-Clipped Optical Orthogonal Frequency-Division Multiplexing (ACO-OFDM) technique is proposed through unipolar encoding. A performance analysis of the Bit Error Rate (BER) is developed and Monte Carlo simulations are carried out to verify the analysis. Results are compared to that of the corresponding ACO-OFDM system under the same bit energy and transmission rate; an improvement of 1 dB is obtained at a BER of 10-4 . In addition, the performance of the proposed system in the presence of atmospheric turbulence is investigated using single-input multiple-output (SIMO) configuration and its performance under that environment is compared to that of ACO-OFDM. Energy improvements of 4 dB and 2.2 dB are obtained at a BER of 10-4 for SIMO systems of 1 and 2 photodetectors at the receiver for the case of strong turbulence, respectively.

  9. High-Speed Turbo-TCM-Coded Orthogonal Frequency-Division Multiplexing Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available One of the UWB proposals in the IEEE P802.15 WPAN project is to use a multiband orthogonal frequency-division multiplexing (OFDM system and punctured convolutional codes for UWB channels supporting a data rate up to 480 Mbps. In this paper, we improve the proposed system using turbo TCM with QAM constellation for higher data rate transmission. We construct a punctured parity-concatenated trellis codes, in which a TCM code is used as the inner code and a simple parity-check code is employed as the outer code. The result shows that the system can offer a much higher spectral efficiency, for example, 1.2 Gbps, which is 2.5 times higher than the proposed system. We identify several essential requirements to achieve the high rate transmission, for example, frequency and time diversity and multilevel error protection. Results are confirmed by density evolution.

  10. Optical wireless communication using positive real-valued orthogonal frequency-division multiplexing and optical beamforming

    Science.gov (United States)

    Kim, Sung-Man; Kwon, Ki-Keun

    2017-07-01

    The relatively unsatisfactory performance of optical wireless communication (OWC) with respect to WiFi and millimeter-wave communications has formed a key issue preventing its commercialization. We experimentally demonstrate an OWC technology using a combination of positive real-valued orthogonal frequency-division multiplexing (OFDM) and optical beamforming (OB). Due to the intensity-modulation and direct-detection aspects of OWC systems, a positive real-valued OFDM signal can be suitably utilized to maximize the OWC data rate. Further, the OB technique, which can focus laser light on a desired target, can be utilized to increase the OWC data rate and transmission distance. Our experimental results show that the received optical signal power and electrical signal increase by up to 42 and 25 dB, respectively. Further, the data rate increases by a factor of 200 with OB over the conventional approach.

  11. Parallel Imaging of 3D Surface Profile with Space-Division Multiplexing

    Directory of Open Access Journals (Sweden)

    Hyung Seok Lee

    2016-01-01

    Full Text Available We have developed a modified optical frequency domain imaging (OFDI system that performs parallel imaging of three-dimensional (3D surface profiles by using the space division multiplexing (SDM method with dual-area swept sourced beams. We have also demonstrated that 3D surface information for two different areas could be well obtained in a same time with only one camera by our method. In this study, double field of views (FOVs of 11.16 mm × 5.92 mm were achieved within 0.5 s. Height range for each FOV was 460 µm and axial and transverse resolutions were 3.6 and 5.52 µm, respectively.

  12. Interferometric characterization of few-mode fibers (FMF) for mode-division multiplexing (MDM)

    DEFF Research Database (Denmark)

    Muliar, Olena; Usuga Castaneda, Mario A.; Rottwitt, Karsten

    2015-01-01

    or optical modes. Mode division multiplexing (MDM) appears in this context as a promising and viable solution for such capacity increase, since it utilizes multiple spatial modes of an optical fiber as individual communication channels for data transmission. In order to evaluate its performance, a MDM system......), commonly used in a MDM scenario. This experimental technique requires the use of a Mach-Zehnder interferometer, where the reference's path length is controlled by an optical delay line. The interference between the output beams of reference and fiber under test (FUT) is recorded on a CCD camera...... link with two optical modes propagating in a FMF, which illustrates its potential as a diagnostic tool for MDM systems....

  13. The ASCI Network for SC '98: Dense Wave Division Multiplexing for Distributed and Distance Computing

    Energy Technology Data Exchange (ETDEWEB)

    Adams, R.L.; Butman, W.; Martinez, L.G.; Pratt, T.J.; Vahle, M.O.

    1999-06-01

    This document highlights the DISCOM's Distance computing and communication team activities at the 1998 Supercomputing conference in Orlando, Florida. This conference is sponsored by the IEEE and ACM. Sandia National Laboratories, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory have participated in this conference for ten years. For the last three years, the three laboratories have a joint booth at the conference under the DOE's ASCI, Accelerated Strategic Computing Initiatives. The DISCOM communication team uses the forum to demonstrate and focus communications and networking developments. At SC '98, DISCOM demonstrated the capabilities of Dense Wave Division Multiplexing. We exhibited an OC48 ATM encryptor. We also coordinated the other networking activities within the booth. This paper documents those accomplishments, discusses the details of their implementation, and describes how these demonstrations support overall strategies in ATM networking.

  14. Actively switchable nondegenerate polarization-entangled photon-pair distribution in dense wave-division multiplexing

    Science.gov (United States)

    Zhou, Zhi-Yuan; Jiang, Yun-Kun; Ding, Dong-Sheng; Shi, Bao-Sen; Guo, Guang-Can

    2013-04-01

    We have demonstrated experimentally a nondegenerate polarization-entangled photon-pair distribution in a commercial telecom dense wave-division multiplexing device (DWDM) with eight channels. A promising point of this experiment is that an entangled photon pair is obtained via spontaneous parametric down conversion in a single type-II periodically poled KTiOPO4 crystal without postselection. Another promising advantage is that we can actively switch the distribution of the photon pair between different channel pairs in DWDM at will. There is no crosstalk between different channel pairs because of a limited emission bandwidth of the source. Maximum raw visibility of 97.88%±0.86% obtained in a Bell-type interference experiment and a Clauser-Horne-Shimony-Holt (CHSH) inequality S parameter of 2.63±0.08 calculated prove high entanglement of our source. Our work is helpful for building quantum communication networks.

  15. Simulation on Peak-to-Average Power Ratio for Orthogonal Frequency Division Multiplexing

    Institute of Scientific and Technical Information of China (English)

    SHAN Weifeng; MENG Baohong; LIU Ningning; LI Hui; ZHANG Hongwei

    2006-01-01

    Clipping is a simple and convenient PAPR (peak-to-average power ratio) reduction method for high speed OFDM (orthogonal frequency division multiplexing) communication system. In this paper, we propose a new PAPR reduction method for Wireless-MAN(metropolitan area network)-OFDM system based on IEEE 802.16, which is over-sampling clipping arithmetic. Simulation and performance of the over-samples clipping's PAPR reduction capability, BER effect is given. The simulation indicates that the PAPR of at least 99.9% OFDM symbol is below 6dB after 2 Nyquist rate clipping, and the performance of BER has 1dB SNR(signal noise ratio) loss. The results prove that this method has better capacity to reducing PAPR. So it can be well used in WMAN-OFDM system.

  16. High-Speed Turbo-TCM-Coded Orthogonal Frequency-Division Multiplexing Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    Wang Yanxia

    2006-01-01

    Full Text Available One of the UWB proposals in the IEEE P802.15 WPAN project is to use a multiband orthogonal frequency-division multiplexing (OFDM system and punctured convolutional codes for UWB channels supporting a data rate up to 480 Mbps. In this paper, we improve the proposed system using turbo TCM with QAM constellation for higher data rate transmission. We construct a punctured parity-concatenated trellis codes, in which a TCM code is used as the inner code and a simple parity-check code is employed as the outer code. The result shows that the system can offer a much higher spectral efficiency, for example, 1.2 Gbps, which is 2.5 times higher than the proposed system. We identify several essential requirements to achieve the high rate transmission, for example, frequency and time diversity and multilevel error protection. Results are confirmed by density evolution.

  17. Digital audio broadcasting by satellite utilising Trellis-Coded Quasi-Orthogonal Code Division Multiplexing

    Science.gov (United States)

    de Gaudenzi, R.

    This paper introduces trellis-coded quasi-orthogonal code division multiplexing (TCQO-CDM) as a transmission technique for digital audio broadcasting. The proposed technique performs well over the satellite L-band fading channel and also in the terrestrial gap-filter type of transmission. Preliminary satellite link budgets based on extensive computer-simulation results are provided. The capacity achieved by the terrestrial single-frequency gap-filler network by using the same satellite frequency and user receiver is also discussed. Numerical results show that a remarkable overall capacity can be achieved by using HEO satellite orbits complemented by a terrestrial gap-filler. A variety of transmission rates and hence broadcasting services can be realized. It is shown that a geostationary satellite can provide limited service availability and limited capacity to mobile users, but can also be used for experimental purposes.

  18. Time-Predictable Communication on a Time-Division Multiplexing Network-on-Chip Multicore

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Bo

    This thesis presents time-predictable inter-core communication on a multicore platform with a time-division multiplexing (TDM) network-on-chip (NoC) for hard real-time systems. The thesis is structured as a collection of papers that contribute within the areas of: reconfigurable TDM NoCs, static...... of the Argo NoC network interface (NI) that supports instantaneous reconfiguration, a TDM traffic scheduler that generates virtual circuit (VC) configurations for the Argo NoC, and software functions for two types of intercore communication. The new generation of the Argo NoC adds the capability...... in terms of shortening the TDM period. The thesis identifies two types of inter-core communication that are commonly used in real-time systems: message passing and state-based communication. We implement message passing as a circular buffer with the data transfer through the NoC. The worst-case execution...

  19. Modular time division multiplexer: Efficient simultaneous characterization of fast and slow transients in multiple samples

    Science.gov (United States)

    Kim, Stephan D.; Luo, Jiajun; Buchholz, D. Bruce; Chang, R. P. H.; Grayson, M.

    2016-09-01

    A modular time division multiplexer (MTDM) device is introduced to enable parallel measurement of multiple samples with both fast and slow decay transients spanning from millisecond to month-long time scales. This is achieved by dedicating a single high-speed measurement instrument for rapid data collection at the start of a transient, and by multiplexing a second low-speed measurement instrument for slow data collection of several samples in parallel for the later transients. The MTDM is a high-level design concept that can in principle measure an arbitrary number of samples, and the low cost implementation here allows up to 16 samples to be measured in parallel over several months, reducing the total ensemble measurement duration and equipment usage by as much as an order of magnitude without sacrificing fidelity. The MTDM was successfully demonstrated by simultaneously measuring the photoconductivity of three amorphous indium-gallium-zinc-oxide thin films with 20 ms data resolution for fast transients and an uninterrupted parallel run time of over 20 days. The MTDM has potential applications in many areas of research that manifest response times spanning many orders of magnitude, such as photovoltaics, rechargeable batteries, amorphous semiconductors such as silicon and amorphous indium-gallium-zinc-oxide.

  20. Joint nonlinearity and chromatic dispersion pre-compensation for coherent optical orthogonal frequency-division multiplexing systems

    Institute of Scientific and Technical Information of China (English)

    Qiao Yao-Jun; Liu Xue-Jun; Ji Yue-Feng

    2011-01-01

    This paper introduces a joint nonlinearity and chromatic dispersion pre-compensation method for coherent optical orthogonal frequency-division multiplexing systems.The research results show that this method can reduce the walkoff effect and can therefore equalize the nonlinear impairments effectively. Compared with the only other existing nonlinearity pre-compensation method,the joint nonlinearity and chromatic dispersion pre-compensation method is not only suitable for low-dispersion optical orthogonal frequency-division multiplexing system,but also effective for highdispersion optical orthogonal frequency-division multiplexing transmission system with higher input power but without optical dispersion compensation.The suggested solution does not increase computation complexity compared with only nonlinearity pre-compensation method.For 40 Gbit/s coherent optical orthogonal frequency-division multiplexing 20 × 80 km standard single-mode fibre system,the suggested method can improve the nonlinear threshold (for Q > 10 dB) about 2.7,1.2 and 1.0 dB,and the maximum Q factor about 1.2,0.4 and 0.3 dB,for 2,8 and 16 ps/(nm·km) dispersion coefficients.

  1. Observation of small sub-pulses out of the delayed-interference signal-wavelength converter

    DEFF Research Database (Denmark)

    Sakaguchi, J.; Nielsen, Mads Lønstrup; Ohira, T.;

    2005-01-01

    The generation of small sub-pulses in the delayed-interference signal-wavelength converter (DISC), which has been studied for use in future 160-Gb/s optical time division multiplexing-wavelength division multiplexing (OTDM-WDM) communication systems, was recently predicted as a potential problem....

  2. Numerical analysis of intermodal delay in few-mode fibers for mode division multiplexing in optical fiber communication systems

    Institute of Scientific and Technical Information of China (English)

    Abid Munir; XIN Xiang-jun; LIU Bo; Abdul Latif; Aftab Hussain; Shahab Ahmad Niazi

    2012-01-01

    In order to achieve higher spectral efficiency,mode division multiplexing (MDM) in few-mode fibers is a new research area.The idea faces lots of technical issues including intermodal delay and mode coupling which limit the achievable length of the system.This paper is designated to complete the analysis of intermodal delay in step-index few-mode fibers.We analyze numerically all the parameters of fiber,which could impact intermodal delay in few-mode fibers and identify the conditions which can increase the number of multiplex modes without significant increase in maximum intermodal delay.

  3. Frequency division multiplexed microwave and baseband digital optical fiber link for phased array antennas

    Science.gov (United States)

    Heim, Peter J.; McClay, C. Phillip

    1990-05-01

    A frequency-division multiplexed optical fiber link is described in which microwave (1-8 GHz) and baseband digital (1-10 Mb/s) signals are combined electrically and transmitted through a direct-modulation microwave optical link. The microwave signal does not affect bit error rate (BER) performance of the Manchester-coded baseband digital data link. The baseband digital signal affects microwave signal quality by generating second-order intermodulation noise. The intermodulation noise power density is found to be proportional to both the microwave input power and the digital input power, enabling the system to be modeled as a mixer (AM modulator). The conversion loss for the digital signal is approximately 68 dB for a 1-GHz microwave signal and is highly dependent on the microwave frequency, reaching a minimum value of 41 dB at 4.5 GHz, corresponding to the laser diode relaxation oscillation frequency. It is shown that Manchester coding on the digital link places the intermodulation noise peak away from the microwave signal, preventing degradation of close-carrier phase noise (<1 kHz offset). A direct trade-off between intermodulation noise and digital link margin is developed to project system performance.

  4. [In situ temperature measurement by absorption spectroscopy based on time division multiplexing technology].

    Science.gov (United States)

    Lou, Nan-zheng; Li, Ning; Weng, Chun-sheng

    2012-05-01

    Tunable diode laser absorption spectroscopy (TDLAS) technology is a kind of high sensitivity, high selectivity of non contacting gas in situ measurement technique. In the present paper, in situ gas temperature measurement of an open environment was achieved by means of direct scanning multiple characteristic lines of H2O and combined with least-squares algorithm. Through the use of HITRAN spectral database, the boundary effect on the gas temperature and concentration measurements was discussed in detail, and results showed that the combination of scanning multiple characteristic lines and least-squares algorithm can effectively reduce the boundary effect on the gas temperature measurements under the open environment. Experiments using time division multiplexing technology to simultaneously scan 7444.36, 7185.60, 7182.95 and 7447.48 cm(-1), the four characteristic H2O lines, the gas temperature of tubular furnace in the range of 573-973 K was measured under different conditions. The maximum temperature difference between absorption spectrum measurement and thermocouple signal was less than 52.4 K, and the maximum relative error of temperature measurement was 6.8%.

  5. Simultaneous detection of randomly arranged multiple barcodes using time division multiplexing technique

    Science.gov (United States)

    Haider, Saad Md. Jaglul; Islam, Md. Kafiul

    2010-02-01

    A method of detecting multiple barcodes simultaneously using time division multiplexing technique has been proposed in this paper to minimize the effective time needed for handling multiple tags of barcodes and to lessen the overall workload. Available barcode detection systems can handle multiple types of barcode but a single barcode at a time. This is not so efficient and can create large queue and chaos in places like mega shopping malls or large warehouses where we need to scan huge number of barcodes daily. Our proposed system is expected to improve the real time identification of goods or products on production lines and in automated warehouses or in mega shopping malls in a much more convenient and efficient way. For identifying of multiple barcodes simultaneously, a particular arrangement and orientation of LASER scanner and reflector have been used with a special curve shaped basement where the barcodes are placed. An effective and novel algorithm is developed to extract information from multiple barcodes which introduces starting pattern and ending pattern in barcodes with bit stuffing technique for the convenience of multiple detections. CRC technique is also used for trustworthiness of detection. The overall system enhances the existing single barcode detection system by a great amount although it is easy to implement and use.

  6. Improvement and Analysis of Carrier-Interferometry Orthogonal Frequency Division Multiplexing System

    Institute of Scientific and Technical Information of China (English)

    HE Jian-hui; QUAN Zi-yi; MEN Ai-dong

    2005-01-01

    This paper proposes to use Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT), instead of vector-matrix multiplication, to implement the spreading/despreading in Carrier-Interferometry Orthogonal Frequency Division Multiplexing (CI/OFDM) and Pseudo-Orthogonal Carrier-Interferometry OFDM (PO-CI/OFDM). That can improve the signal processing efficiency of CI/OFDM and PO-CI/OFDM systems by about 2N/log2N and 2N/(1+log2N) times respectively and dose not make any difference to the system function and performance. Moreover, the efficiency benefits will increase with the increase of the number of sub-carriers. In addition to that, we point out that the transmitter of CI/OFDM is actually technically equivalent to that of a single-carrier system with cyclic-prefix and the receiver of CI/OFDM is a typical OFDM receiver with CI despreading. Hence the low Peak-to-Average Power Ratio (PAPR) property and high anti-fading performance of CI/OFDM system can be well explained.

  7. On-chip two-mode division multiplexing using tapered directional coupler-based mode multiplexer and demultiplexer

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Da Ros, Francesco

    2013-01-01

    ), and large fabrication tolerance (20 nm) are measured. An on-chip mode multiplexing experiment is carried out on the fabricated circuit with non return-to-zero (NRZ) on-off keying (OOK) signals at 40 Gbit/s. The experimental results show clear eye diagrams and moderate power penalty for both TE0 and TE1...

  8. Investigación sobre spatial-division multiplexing (SDM) en comunicaciones por fibra óptica

    OpenAIRE

    Latorre Campos, Borja

    2016-01-01

    Investigación sobre spatial-division multiplexing (SDM) en comunicaciones por fibra óptica In this work we analyze propagating LP modes (Linearly Polarized) in different independent spatial paths, mentioning the energetic density of the electromagnetic fields of these modes with a fixed normalized frequency and the evolution during the normalized frequency’s increment too. Thus, we have implemented an analytic and visual study through MATLAB programming language. En este trabajo analiza...

  9. 640 Gbit/s time-division add-drop multiplexing using a non-linear polarisation-rotating fibre loop

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Galili, Michael; Grüner-Nielsen, Lars

    2008-01-01

    We report the first demonstration of error-free 640 Gbit/s time-division add-drop multiplexing, performed by non-linear polarisation-rotation using a loop with a polarisation-maintaining HNLF.......We report the first demonstration of error-free 640 Gbit/s time-division add-drop multiplexing, performed by non-linear polarisation-rotation using a loop with a polarisation-maintaining HNLF....

  10. All-Optical Switches in Optical Time-Division Multiplexing Technology: Theory,Experience and Application

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Optical time division multiplexing (OTDM) is one of thepromisinig ways for the future high-speed optical fiber communication networks. All-optical switch is, being one of the core technologies of OTDM systems and networks, crucial to realize the various signal processes including time-division demultiplexing, packet switching, all-optical regenerating and so on. This thesis mainly studies various all-optical switch technologies and their utilization in the fields of all-optical signal processings in the OTDM systems and networks. The main jobs are listed as follows.(1) A novel all-optical ultrafast demultiplexing scheme using the soliton self-trapping effect in birefringent fiber is proposed.(2) The demultiplexing performance of the Nonlinear Optical Loop Mirror(NOLM) is thoroughly analyzed and its optimization is further discussed.(3) The performance analysis and the configuration optimization of the all-optical switches based on the Semiconductor Optical Amplifier(SOA) are systematically presented. The speed limitation of the all-optical SOA switches induced by the fast gain depletion of SOA is discussed. Besides, a novel SOA switch is proposed, which adopts the asymmetric Mach-Zehnder Interferometer configuration.(4) The 8×2\\^5 Gb/s OTDM experimental transmission system along 105 km standard fiber is realized using the NOLM demultiplexer.(5) The NOLM switch is used to realize the all-optical 3R regeneration of 2\\^5 Gb/s Return-to-Zero signal.(6) The feasibility and limitation of the all-optical SOA packet switch is discussed. And a developed MZI configuration of SOA packet switch is further shown to improve the packet switching performance. Finally, an all-optical packet dropping node suitable in the networks with ring or bus configuration and an all-optical packet switching node in the ShuffleNet networks are proposed to show the feasibility of all-optical packet switching through combining the all-optical switches and the reasonable logic decisions.

  11. Frequency-Division Multiplexing for Electrical Impedance Tomography in Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Yair Granot

    2007-01-01

    Full Text Available Electrical impedance tomography (EIT produces an image of the electrical impedance distribution of tissues in the body, using electrodes that are placed on the periphery of the imaged area. These electrodes inject currents and measure voltages and from these data, the impedance can be computed. Traditional EIT systems usually inject current patterns in a serial manner which means that the impedance is computed from data collected at slightly different times. It is usually also a time-consuming process. In this paper, we propose a method for collecting data concurrently from all of the current patterns in biomedical applications of EIT. This is achieved by injecting current through all of the current injecting electrodes simultaneously, and measuring all of the resulting voltages at once. The signals from various current injecting electrodes are separated by injecting different frequencies through each electrode. This is called frequency-division multiplexing (FDM. At the voltage measurement electrodes, the voltage related to each current injecting electrode is isolated by using Fourier decomposition. In biomedical applications, using different frequencies has important implications due to dispersions as the tissue's electrical properties change with frequency. Another significant issue arises when we are recording data in a dynamic environment where the properties change very fast. This method allows simultaneous measurements of all the current patterns, which may be important in applications where the tissue changes occur in the same time scale as the measurement. We discuss the FDM EIT method from the biomedical point of view and show results obtained with a simple experimental system.

  12. Multiplexing technique using amplitude-modulated chirped fibre Bragg gratings with applications in two-parameter sensing

    Science.gov (United States)

    Wong, Allan C. L.; Childs, Paul A.; Peng, Gang-Ding

    2007-11-01

    A multiplexing technique using amplitude-modulated chirped fibre Bragg gratings (AMCFBGs) is presented. This technique realises the multiplexing of spectrally overlapped AMCFBGs with identical centre Bragg wavelength and bandwidth. Since it is fully compatible with the wavelength division multiplexing scheme, the number of gratings that can be multiplexed can be increased by several times. The discrete wavelet transform is used to demodulate such multiplexed signal. A wavelet denoising technique is applied to the multiplexed signal in conjunction with the demodulation. Strain measurements are performed to experimentally demonstrate the feasibility of this multiplexing technique. The absolute error and crosstalk are measured. An application to simultaneous two-parameter sensing is also demonstrated.

  13. Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection.

    Science.gov (United States)

    Takasago, K; Takekawa, M; Shirakawa, A; Kannari, F

    2000-05-10

    A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M-sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M-sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of ~5.

  14. Single telecom photon heralding by wavelength multiplexing in an optical fiber

    Science.gov (United States)

    Lenhard, Andreas; Brito, José; Kucera, Stephan; Bock, Matthias; Eschner, Jürgen; Becher, Christoph

    2016-01-01

    We demonstrate the multiplexing of a weak coherent and a quantum state of light in a single telecommunication fiber. For this purpose, we make use of spontaneous parametric down conversion and quantum frequency conversion to generate photon pairs at 854 nm and the telecom O-band. The herald photon at 854 nm triggers a telecom C-band laser pulse. The telecom single photon (O-band) and the laser pulse (C-band) are combined and coupled to a standard telecom fiber. Low-background time correlation between the weak coherent and quantum signal behind the fiber shows successful multiplexing.

  15. Dark soliton interaction in optical time division multiplexed system with randomly varying birefringence and random dispersion map

    Institute of Scientific and Technical Information of China (English)

    Hong Li(李宏); Tiejun Wang(王铁军); Dexiu Huang(黄德修)

    2004-01-01

    Correlated perturbations caused by both randomly varying birefringence and random dispersion map are considered in optical time division multiplexed dispersion-managed dark soliton system, and their effects on soliton interaction are investigated numerically. These perturbations enhance soliton interaction, and their effects relate to the strength of perturbation, separation, and pulse width. The correlation plays an important role and reinforces these effects. Moreover, there is a stochastic limit between two perturbations in the system, where the effect is the largest and the corresponding interaction distance is the shortest.

  16. 10 Mb/s visible light transmission system using a polymer light-emitting diode with orthogonal frequency division multiplexing.

    Science.gov (United States)

    Le, Son T; Kanesan, T; Bausi, F; Haigh, P A; Rajbhandari, S; Ghassemlooy, Z; Papakonstantinou, I; Popoola, W O; Burton, A; Le Minh, H; Cacialli, F; Ellis, A D

    2014-07-01

    We present a newly designed polymer light-emitting diode with a bandwidth of ~350  kHz for high-speed visible light communications. Using this new polymer light-emitting diode as a transmitter, we have achieved a record transmission speed of 10  Mb/s for a polymer light-emitting diode-based optical communication system with an orthogonal frequency division multiplexing technique, matching the performance of single carrier formats using multitap equalization. For achieving such a high data-rate, a power pre-emphasis technique was adopted.

  17. Modeling and characterization of a few-mode EDFA supporting four mode groups for mode division multiplexing.

    Science.gov (United States)

    Le Cocq, Guillaume; Bigot, Laurent; Le Rouge, Antoine; Bigot-Astruc, Marianne; Sillard, Pierre; Koebele, Clemens; Salsi, Massimilliano; Quiquempois, Yves

    2012-11-19

    Numerical and experimental study of a Few-Mode (FM) Erbium Doped Fiber Amplifier (EDFA) suitable for mode division multiplexing (MDM) is reported. Based on numerical simulations, a Few-Mode Erbium Doped Fiber (FM-EDF) has been designed to amplify four mode groups and to equally amplify LP11 and LP21 mode groups with gains greater than 20 dB and with a differential modal gain of less than 1 dB. Experimental results confirmed the simulations with a good concordance. This modal gain equalization is obtained by tailoring the erbium spatial distribution in the fiber core with a ring-shaped profile.

  18. 40-Gbps vestigial sideband half-cycle Nyquist subcarrier modulation transmission experiment and its comparison with orthogonal frequency division multiplexing

    Science.gov (United States)

    Liu, Na; Chen, Xue; Ju, Cheng; Hui, Rongqing

    2014-09-01

    We experimentally demonstrate the superior performance of a 40-Gbps 16-QAM half-cycle Nyquist subcarrier modulation (SCM) transmission over a 100-km uncompensated standard single-mode fiber using dual-drive Mach-Zehnder modulator-based vestigial sideband intensity modulation and direct detection. The impact of modulator chirp on the system performance is experimentally evaluated. This Nyquist-SCM technique is compared with optical orthogonal frequency division multiplexing in both back-to-back and 100-km transmission experiments, and the results show that the Nyquist system has a better performance.

  19. Fiber-distributed feedback lasers for high-speed wavelength-division multiplexed networks

    DEFF Research Database (Denmark)

    Sejka, Milan; Hübner, Jörg; Varming, Poul

    1996-01-01

    Summary form only given. In conclusion, we have demonstrated that fiber DFB lasers constitute an excellent alternative to commercially available semiconductor DFB lasers. We have also shown that two fiber DFB lasers can be spliced together without any BER power penalty. Therefore, we suggest the ...... the possibility of using a single pump source for pumping a WDM laser array consisting of a number of fiber lasers spliced in series....

  20. All fiber optical inter-band router for broadband wavelength division multiplexing.

    Science.gov (United States)

    Shin, W; Han, S; Park, C; Oh, K

    2004-05-03

    We propose a new type of all-fiber device for inter-band router using a novel hybrid waveguide-MEMS technology. Both continuous and discrete band-routing functions are realized by precise twist control over the fused coupling region, which results in pi phase shift between the output ports. Experimentally we demonstrate inter-band routing functions between O and C-band as well as between E and L-band with a low insertion loss, wide bandwidth of operation, high channel isolation and fast response.

  1. Design of Raman-parametric fiber amplifier for wavelength division multiplex transmission system

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Jiang; Chun Jiang; Xiaoming Zhang

    2008-01-01

    We optimize the novel configuration of a hybrid fiber amplifier-Raman assisted-fiber-based optical parametric amplifier (R-FOPA), in which the parametric gain and Raman gain profiles are combined to achieve a flat composite gain profile.The pump powers and the fiber length in the hybrid amplifier are effectively optimized by genetic algorithm (GA) scheme.The optimization results indicate that the R-FOPA can achieve a 200-nm flat bandwidth spectrum with the gain of 20 dB and ripple of less than 4 dB.

  2. Recent Advances of Distributed Optical Fiber Raman Amplifiers in Ultra Wide Wavelength Division Multiplexing Telecommunication Networks

    Directory of Open Access Journals (Sweden)

    Abd El–Naser A. Mohamed

    2012-05-01

    Full Text Available Recently, many research works have been focused on the fiber optic devices for optical communication systems. One of the main interests is on the optical amplifiers to boost a weak signal in the communication systems. In order to overcome the limitations imposed by electrical regeneration, a means of optical amplification was sought. The competing technology emerged: the first was Raman amplification. One reason was that the optical pump powers required for Raman amplification were significantly higher than that for Erbium doped fiber amplifier (EDFA, and the pump laser technology could not reliably deliver the required powers. However, with the improvement of pump laser technology Raman amplification is now an important means of expanding span transmission reach and capacity. We have deeply studied an analytical model for optical distributed Raman amplifiers (DRAs in the transmission signal power and pump power within Raman amplification technique in co-pumped, counter-pumped, and bi-directional pumping direction configurations through different types of fiber cable media. The validity of this model was confirmed by using experimental data and numerical simulations.

  3. Coherent Detection of Wavelength Division Multiplexed Phase-Modulated Radio-over-Fibre Signals

    DEFF Research Database (Denmark)

    Zibar, Darko; Yu, Xianbin; Peucheret, Christophe

    2008-01-01

    A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km.......A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km....

  4. Gain transient control for wavelength division multiplexed access networks using semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Osadchiy, Alexey Vladimirovich; Kjær, Rasmus;

    2009-01-01

    measurements how a near-saturated semiconductor optical amplifier (SOA) can be used to control these gain transients. An SOA is shown to reduce the penalty of transients originating in an EDFA from 2.3 dB to 0.2 dB for 10 Gb/s transmission over standard single mode fiber using a 231-1 PRBS pattern. The results...

  5. Multi-wavelength integrated optical beamformer based on Wavelength division multiplexing for 2-D phased array antennas

    NARCIS (Netherlands)

    Burla, Maurizio; Marpaung, David; Zhuang, Leimeng; Khan, Muhannad Rezaul; Leinse, Arne; Beeker, Willem; Hoekman, Marcel; Heideman, René; Roeloffzen, Chris

    2014-01-01

    A novel, hardware-compressive architecture for broadband and continuously tunable integrated optical truetime- delay beamformers for phased array antennas is proposed and experimentally demonstrated. The novel idea consists in employing the frequency-periodic response of optical ring resonator (ORR)

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

    Science.gov (United States)

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

    2016-10-01

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

  7. Dense wavelength multiplexing of 1550 nm QKD with strong classical channels in reconfigurable networking environments

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Danna [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory; Dallmann, Nicholas [Los Alamos National Laboratory; Hughes, Richard J [Los Alamos National Laboratory; Mccabe, Kevin P [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; Tyagi, Hush T [Los Alamos National Laboratory; Peters, Nicholas A [TELCORDIA TECHNOLOGIES; Toliver, Paul [TELCORDIA TECHNOLOGIES; Chapman, Thomas E [TELCORDIA TECHNOLOGIES; Runser, Robert J [TELCORDIA TECHNOLOGIES; Mcnown, Scott R [TELCORDIA TECHNOLOGIES

    2008-01-01

    To move beyond dedicated links and networks, quantum communications signals must be integrated into networks carrying classical optical channels at power levels many orders of magnitude higher than the quantum signals themselves. We demonstrate transmission of a 1550-nm quantum channel with up to two simultaneous 200-GHz spaced classical telecom channels, using ROADM (reconfigurable optical <1dd drop multiplexer) technology for multiplexing and routing quantum and classical signals. The quantum channel is used to perform quantum key distribution (QKD) in the presence of noise generated as a by-product of the co-propagation of classical channels. We demonstrate that the dominant noise mechanism can arise from either four-wave mixing or spontaneous Raman scattering, depending on the optical path characteristics as well <1S the classical channel parameters. We quantity these impairments and discuss mitigation strategies.

  8. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul;

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  9. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  10. Investigation of Alien Wavelength Quality in Live Multi-Domain, Multi-Vendor Link Using Advanced Simulation Tool

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Nuijts, Roeland; Bjorn, Lars Lange

    2014-01-01

    This article presents an advanced optical model for simulation of alien wavelengths in multi-domain and multi-vendor dense wavelength-division multiplexing networks. The model aids optical network planners with a better understanding of the non-linear effects present in dense wavelength-division ......This article presents an advanced optical model for simulation of alien wavelengths in multi-domain and multi-vendor dense wavelength-division multiplexing networks. The model aids optical network planners with a better understanding of the non-linear effects present in dense wavelength......-division multiplexing systems and better utilization of alien wavelengths in future applications. The limiting physical effects for alien wavelengths are investigated in relation to power levels, channel spacing, and other factors. The simulation results are verified through experimental setup in live multi...

  11. Analysis and Research of Multiplexing System

    Institute of Scientific and Technical Information of China (English)

    郭惠玲; 王仝杰; 刘越男

    2001-01-01

    The development of optical transmission was summarized. The multiplexing system was show in detail. The concepts, characteristic, key technology, expand trend and application prospect of frequency-division multiplexing, time-division multiplexing, code-division multiplexing and wave-division multiplexing were illustrated.

  12. Ultrabright fluorescent silica particles with a large number of complex spectra excited with a single wavelength for multiplex applications.

    Science.gov (United States)

    Palantavida, S; Peng, B; Sokolov, I

    2017-02-08

    We report on a novel approach to synthesize ultrabright fluorescent silica particles capable of producing a large number of complex spectra. The spectra can be excited using a single wavelength which is paramount in quantitative fluorescence imaging, flow cytometry and sensing applications. The approach employs the physical encapsulation of organic fluorescent molecules inside a nanoporous silica matrix with no dye leakage. As was recently demonstrated, such an encapsulation allowed for the encapsulation of very high concentrations of organic dyes without quenching their fluorescent efficiency. As a result, dye molecules are distanced within ∼5 nm from each other; it theoretically allows for efficient exchange of excitation energy via Förster resonance energy transfer (FRET). Here we present the first experimental demonstration of the encapsulation of fluorescent dyes in the FRET sequence. Attaining a FRET sequence of up to five different dyes is presented. The number of distinguishable spectra can be further increased by using different relative concentrations of encapsulated dyes. Combining these approaches allows for creating a large number of ultrabright fluorescent particles with substantially different fluorescence spectra. We also demonstrate the utilization of these particles for potential multiplexing applications. Though fluorescence spectra of the obtained multiplex probes are typically overlapping, they can be distinguished by using standard linear decomposition algorithms.

  13. Distributed optical multiplexing with precise frequency allocation using fiber frequency conversion

    Science.gov (United States)

    Kato, Tomoyuki; Okabe, Ryo; Watanabe, Shigeki

    2013-12-01

    Effective utilization of fiber capacity in optical communication networks is required to keep up with the increasing traffic demand. Precise optical frequency allocation among carriers is essential for improving the spectral efficiency to utilize the limited spectral resource. In this paper, we show a distributed optical multiplexing scheme, in which data signals are sequentially multiplexed by frequency-division multiplexing on a single-wavelength optical carrier using fiber frequency conversion with locally provided optical subcarrier signals. The scheme achieves dense packing of distributed multi-channel signals with precise frequency allocation using free-running lasers. Using the scheme we demonstrate a precise multiplexing of coherent-optical orthogonal frequency-division multiplexing and Nyquist wavelength-division multiplexing.

  14. Design of Three-mode Multi/Demultiplexer Based on 2-D Photonic Crystals for Mode-Division Multiplexing Transmission

    Science.gov (United States)

    Fu, PeiDong; Chen, Heming

    2017-06-01

    A three mode division multiplexer and demultiplexer (MMUX/DEMMUX) base on 2-D photonic crystal at 1550 nm was designed. Two asymmetrical directional couplers are included in this MMUX/DEMMUX, which can achieve modes conversion function of TE0, TE1 and TE2 modes. In order to avoid phase mismatching in bus waveguide, taper directional is applied at waveguide junction which can reduce the insertion loss effectively. Plane waves method (PWM) and finite difference time domain (FDTD) methods were used to simulating the performance of MMUX/DEMMUX. Numerical simulations show that the designed device has the potential for high-capacity MDM optical communication systems with a low insertion loss (<0.27dB) and a low mode crosstalk (< -25.4 dB).

  15. Crosstalk-aware routing, spectrum, and core assignment in space-division multiplexing optical networks with multicore fibers

    Science.gov (United States)

    Yao, Qiuyan; Yang, Hui; Xiao, Hongyun; Zhao, Yongli; Zhu, Ruijie; Zhang, Jie

    2017-06-01

    The transmission capacity of existing optical fiber will reach its physical limitation due to increasing network bandwidth. Recently, space-division multiplexing (SDM) technology has been proposed to increase the fiber transmission capacity. Multicore fiber (MCF) is a strong candidate for SDM transmission, but the intercore crosstalk will be a critical issue with MCF transmission. We make a specific analysis of transmission crosstalk in elastic optical networks. Then, the concept of spare spectrum availability is introduced to accommodate connection requests. Based on it, two different crosstalk-aware routing, spectrum, and core assignment algorithms are presented at different network states. Simulation results show that our proposed scheme improves the spectrum resource utilization and reduces blocking, with a cost of additional algorithm complexity and set-up delay.

  16. Performance Analysis of the Multiband Orthogonal Frequency Division Multiplexing Ultra-Wideband Systems for Multipath Fading and Multiuser Interference Channels

    Directory of Open Access Journals (Sweden)

    Yuan Ouyang

    2015-01-01

    Full Text Available This paper presents the performance analysis of the multiband orthogonal frequency division multiplexing (MB-OFDM ultra-wideband (UWB systems for multipath fading and multiuser interference channels. A closed form approximation of the BER performance of the MB-OFDM UWB system with multiple interferences is proposed. Based on the derived approximation, the effects on the BER performance for the choice of the codeword constraint lengths of the convolutional encoder, the length of the cyclic prefix, and the multiuser environments of two or more interferers are thoroughly discussed. Four UWB multipath fading channels are also investigated for the BER performance of the MB-OFDM UWB system. The simulated results provide us with useful information to appropriately choose the parameters of the MB-OFDM UWB system for the sake of achieving the BER performance that conforms to requirement of the FCC standards.

  17. A joint synchronization parameter estimation in fractional Fourier transform orthogonal frequency division multiplexing underwater acoustic communication system

    Directory of Open Access Journals (Sweden)

    Jia-chun Zheng

    2016-03-01

    Full Text Available In the conditions of Gaussian noise, symmetric alpha stable impulse noise, multipath propagation, Doppler effect, and so on, a joint synchronization algorithm is proposed for underwater acoustic communication system based on fractional Fourier transform orthogonal frequency division multiplexing. The algorithm realizes the orthogonal multicarrier underwater acoustic communication system synchronization based on that the symmetrical triangular linear frequency modulation signal has the energy convergence in the domain of fractional Fourier transform. In order to verify the effectiveness of the algorithm, hyperbolic frequency modulation signal and linear frequency modulation signal are used as the evaluation index, and the synchronization performance of bit error rate of them is compared by simulation and pool experiments. The simulation results show that the proposed algorithm in this article is resistant to Gaussian noise, symmetric alpha stable pulse noise, multipath propagation, and Doppler effect, compared with traditional synchronization algorithms; the synchronization error probability is low at the same signal-to-noise ratio.

  18. White light-emitting diode based wireless orthogonal frequency division multiplexing link with improved transmission capacity using Bayesian compressive sensing

    Science.gov (United States)

    Won, Yong-Yuk; Seo, Dong-Sun; Yoon, Sang Min

    2016-04-01

    We propose a technique that improves the channel capacity of an optical wireless orthogonal frequency division multiplexing (OFDM) transmission, which employs a visible light-emitting diode. An OFDM waveform encoded by quadrature phase shift keying (QPSK) or 16-quadrature amplitude modulation is compressed and then transformed into a sparse waveform using a proposed advanced systematic sampling. At the optical wireless receiver, the original waveform is recovered by L1-minimization based on a Bayesian compressive sensing. Our experimental results show the significant increase in the channel capacity from 31.12 to 51.87 Mbit/s at forward error correction limit (i.e., error vector magnitude of 32%) in case of QPSK symbols.

  19. An all-digital receiver for satellite audio broadcasting signals using trellis coded quasi-orthogonal code-division multiplexing

    Science.gov (United States)

    Braun, Walter; Eglin, Peter; Abello, Ricard

    1993-02-01

    Spread Spectrum Code Division Multiplex is an attractive scheme for the transmission of multiple signals over a satellite transponder. By using orthogonal or quasi-orthogonal spreading codes the interference between the users can be virtually eliminated. However, the acquisition and tracking of the spreading code phase can not take advantage of the code orthogonality since sequential acquisition and Delay-Locked loop tracking depend on correlation with code phases other than the optimal despreading phase. Hence, synchronization is a critical issue in such a system. A demonstration hardware for the verification of the orthogonal CDM synchronization and data transmission concept is being designed and implemented. The system concept, the synchronization scheme, and the implementation are described. The performance of the system is discussed based on computer simulations.

  20. Channel estimation scheme based on compressed sensing and parameter estimation for an orthogonal frequency division multiplexing visible light communications system

    Science.gov (United States)

    Du, Jie; Deng, Honggui; Qian, Xuewen; Zhang, Chaoyang

    2016-11-01

    In order to mitigate bandwidth attenuation of diffusion link visible light communication systems caused by multipath effects, we present an optical orthogonal frequency division multiplexing channel estimation scheme based on compressed sensing (CS) and estimation of signal parameters via rotational invariance techniques (ESPRIT). First, we derived a parametric channel model. Then, we used ESPRIT to obtain multipath channel parameters. After that, we built a dynamic over-complete dictionary that can be used in CS processing. Finally, we reconstructed the channel response by using a basis pursuit denoising algorithm to equalize the received signal in frequency domain. Compared with traditional schemes, the proposed scheme can improve channel estimation accuracy without increasing dictionary size. A set of computer simulations demonstrated the effectiveness of the proposed scheme.

  1. A Preamble-Based Frequency Offset Compensation Scheme in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing Systems

    Directory of Open Access Journals (Sweden)

    Elnaz Ershadi

    2010-01-01

    Full Text Available Problem statement: Combining the properties of Multiple Input Multiple Output (MIMO systems with those of Orthogonal Frequency Division Multiplexing (OFDM, MIMO-OFDM was considered to be a promising technique in the future of wireless communications. However, its sensitivity to frequency offsets which results in Inter-Carrier Interferences (ICIs makes it necessary to use an exact frequency offset estimation method for data recovery in the MIMO-OFDM receiver. Approach: In this study, a new preamble-based frequency offset compensation method was introduced in frequency domain. In each block, two preambles are used to initially obtain the channel coefficients through LS channel estimation method. A polynomial curve fitting algorithm was then applied so that the frequency offsets experienced by every single data subcarrier are separately determined. Finally, to improve the compensating process, an iterative algorithm was applied. Results: Simulation results clearly showed that our proposed method was accurate in multipath fading channels and precisely recovered the transmitted data symbols. The BER performance of the iterative algorithm is within an acceptable distance of that in the ideal channel. Conclusion: In comparison with the conventional methods, our proposed scheme was less complex and showed better performance in lower SNRs. For further research, it can be investigated and improved while considering correlated antennas and spatial multiplexing.

  2. Efficient transmission of 1D and 2D chaotic map encrypted images with orthogonal frequency division multiplexing

    Science.gov (United States)

    Kasem, Hossam M.; Nasr, Mohamed E.; Sallam, Elsayed A.; Abd El-Samie, F. E.

    2011-10-01

    Image transmission takes place as an important research branch in multimedia broadcasting communication systems in the last decade. Our paper presents image transmission over a FFT-OFDM (Fast Fourier Transform Orthogonal Frequency Division Multiplexing). The need for encryption techniques increase with the appearance of the expression which said that our world became small village, and the use of image application such as conference and World Wide Web which increase rapidly in recent years. Encryption is an effective method for protecting the transmitted data by converting it into a form being invisible over transmission path and visible in receiver side. This paper presents a new hybrid encryption technique based on combination of Backer maps and logistic map. This proposed technique aims to increase PSNR and reduce the noise in the received image. The encryption is done by shuffling the positions of a pixel image using two dimensional Baker maps then encrypt using XOR operation with logistic map to generate cipher image over orthogonal frequency multiplexing (OFDM). The encryption approach adopted in this paper is based on chaotic Baker maps because the encoding and decoding steps in this approach are simple and fast enough for HDTV applications. The experimental results reveal the superiority of the proposed chaotic based image encryption technique using two logistic maps and two dimensional Backer map over normal Backer map.

  3. Long-Haul Dense Space Division Multiplexed Transmission over Low-Crosstalk Heterogeneous 32-Core Transmission Line Using Partial Recirculating Loop System

    DEFF Research Database (Denmark)

    Mizuno, Takayuki; Shibahara, Kohki; Ye, Feihong

    2017-01-01

    In this paper, we present long-haul 32-core dense space division multiplexed (DSDM) unidirectional transmission over a single-mode multicore transmission line. We developed a low-crosstalk heterogeneous 32-core fiber with a square lattice arrangement, and a novel partial recirculating loop system...

  4. Multiplexing PKA and ERK1&2 kinases FRET biosensors in living cells using single excitation wavelength dual colour FLIM

    Science.gov (United States)

    Demeautis, Claire; Sipieter, François; Roul, Julien; Chapuis, Catherine; Padilla-Parra, Sergi; Riquet, Franck B.; Tramier, Marc

    2017-01-01

    Monitoring of different signalling enzymes in a single assay using multiplex biosensing provides a multidimensional workspace to elucidate biological processes, signalling pathway crosstalk, and determine precise sequence of events at the single living cell level. In this study, we interrogate the complexity in cAMP/PKA-MAPK/ERK1&2 crosstalk by using multi-parameter biosensing experiments to correlate biochemical activities simultaneously in time and space. Using a single excitation wavelength dual colour FLIM method we are able to detect fluorescence lifetime images of two donors to simultaneously measure PKA and ERK1&2 kinase activities in the same cellular localization by using FRET biosensors. To this end, we excite two FRET donors mTFP1 and LSSmOrange with a 440 nm wavelength and we alleviate spectral bleed-through associated limitations with the very dim-fluorescent acceptor ShadowG for mTFP1 and the red-shifted mKate2 for LSSmOrange. The simultaneous recording of PKA and ERK1&2 kinase activities reveals concomitant EGF-mediated activations of both kinases in HeLa cells. Under these conditions the subsequent Forskolin-induced cAMP release reverses the transient increase of EGF-mediated ERK1&2 kinase activity while reinforcing PKA activation. Here we propose a validated methodology for multiparametric kinase biosensing in living cells using FRET-FLIM. PMID:28106114

  5. Ultrafast wavelength multiplexed broad bandwidth digital diffuse optical spectroscopy for in vivo extraction of tissue optical properties

    Science.gov (United States)

    Torjesen, Alyssa; Istfan, Raeef; Roblyer, Darren

    2017-03-01

    Frequency-domain diffuse optical spectroscopy (FD-DOS) utilizes intensity-modulated light to characterize optical scattering and absorption in thick tissue. Previous FD-DOS systems have been limited by large device footprints, complex electronics, high costs, and limited acquisition speeds, all of which complicate access to patients in the clinical setting. We have developed a new digital DOS (dDOS) system, which is relatively compact and inexpensive, allowing for simplified clinical use, while providing unprecedented measurement speeds. The dDOS system utilizes hardware-integrated custom board-level direct digital synthesizers and an analog-to-digital converter to generate frequency sweeps and directly measure signals utilizing undersampling at six wavelengths modulated at discrete frequencies from 50 to 400 MHz. Wavelength multiplexing is utilized to achieve broadband frequency sweep measurements acquired at over 97 Hz. When compared to a gold-standard DOS system, the accuracy of optical properties recovered with the dDOS system was within 5.3% and 5.5% for absorption and reduced scattering coefficient extractions, respectively. When tested in vivo, the dDOS system was able to detect physiological changes throughout the cardiac cycle. The new FD-dDOS system is fast, inexpensive, and compact without compromising measurement quality.

  6. Nanofabrication and test of novel diffractive optics for OAM-mode division multiplexing in optical fibers

    Science.gov (United States)

    Ruffato, G.; Massari, M.; Romanato, F.

    2016-09-01

    The orbital angular momentum (OAM) of light offers a promising solution to today's overwhelming demand of bandwidth and has known an increasing attention as a new degree of freedom in the telecom field. Here we present the design, fabrication and optical characterization of miniaturized phase-only diffractive optical elements (DOE) for OAM beams generation, multiplexing and sorting. Samples have been fabricated with high-resolution electron-beam lithography and exhibit high fabrication quality. Different DOE designs are presented for the sorting of optical vortices with different steering geometries in far-field and applications in free-space and optical fibers.

  7. Theoretical Analysis of a Vertical Channel Dropping Tunnelling Process in a Photonic Crystal for Wavelength Division Demultiplexing

    Institute of Scientific and Technical Information of China (English)

    符建; 何赛灵; 肖三水; 仇霪; 何建军

    2001-01-01

    A theoretical analysis is presented for a channel drop tunnelling structure composed of a horizontal input channel, a vertical output channel and a multi-mode cavity in a photonic crystal. Criteria for a complete transfer are derived for applications of wavelength division demultiplexing. The analytical results are verified with a numerical simulation using a finite difference time domain method. The vertical channel dropping tunnelling system makes the demultiplexing device much more compact, as compared to the conventional parallel channel dropping system.

  8. Wavelength conversion devices and techniques

    DEFF Research Database (Denmark)

    Stubkjær, Kristian; Jørgensen, Carsten; Danielsen, Søren Lykke;

    1996-01-01

    Wavelength division multiplexed (WDM) networks are currently subject to an immense interest because of the extra capacity and flexibility they provide together with the possibilities for graceful system upgrades. For full network flexibility it is very attractive to be able to translate the chann...... wavelengths in an easy way and preferably without opto-electronic conversion. Here, we will first briefly look at advantages of employing optical wavelength converters in WDM networks and next review the optical wavelength conversion devices with emphasis on recent developments....

  9. Mode division multiplexing using an orbital angular momentum mode sorter and MIMO-DSP over a graded-index few-mode optical fibre.

    Science.gov (United States)

    Huang, Hao; Milione, Giovanni; Lavery, Martin P J; Xie, Guodong; Ren, Yongxiong; Cao, Yinwen; Ahmed, Nisar; An Nguyen, Thien; Nolan, Daniel A; Li, Ming-Jun; Tur, Moshe; Alfano, Robert R; Willner, Alan E

    2015-10-09

    Mode division multiplexing (MDM)- using a multimode optical fiber's N spatial modes as data channels to transmit N independent data streams - has received interest as it can potentially increase optical fiber data transmission capacity N-times with respect to single mode optical fibers. Two challenges of MDM are (1) designing mode (de)multiplexers with high mode selectivity (2) designing mode (de)multiplexers without cascaded beam splitting's 1/N insertion loss. One spatial mode basis that has received interest is that of orbital angular momentum (OAM) modes. In this paper, using a device referred to as an OAM mode sorter, we show that OAM modes can be (de)multiplexed over a multimode optical fiber with higher than -15 dB mode selectivity and without cascaded beam splitting's 1/N insertion loss. As a proof of concept, the OAM modes of the LP11 mode group (OAM-1,0 and OAM+1,0), each carrying 20-Gbit/s polarization division multiplexed and quadrature phase shift keyed data streams, are transmitted 5km over a graded-index, few-mode optical fibre. Channel crosstalk is mitigated using 4 × 4 multiple-input-multiple-output digital-signal-processing with <1.5 dB power penalties at a bit-error-rate of 2 × 10(-3).

  10. 32-core Inline Multicore Fiber Amplifier for Dense Space Division Multiplexed Transmission Systems

    DEFF Research Database (Denmark)

    Jain, S.; Mizuno, T.; Jung, Y.

    2016-01-01

    We present a high-core-count SDM amplifier, i.e. 32-core multicore-fiber amplifier, in a cladding-pumped configuration. An average gain of 17dB and NF of 7dB is obtained for -5dBm input signal power in the wavelength range 1544nm-1564nm....

  11. Cascaded Mach-Zehnder wavelength filters in silicon photonics for low loss and flat pass-band WDM (de-)multiplexing.

    Science.gov (United States)

    Horst, Folkert; Green, William M J; Assefa, Solomon; Shank, Steven M; Vlasov, Yurii A; Offrein, Bert Jan

    2013-05-20

    We present 1-to-8 wavelength (de-)multiplexer devices based on a binary tree of cascaded Mach-Zehnder-like lattice filters, and manufactured using a 90 nm CMOS-integrated silicon photonics technology. We demonstrate that these devices combine a flat pass-band over more than 50% of the channel spacing with low insertion loss of less than 1.6 dB, and have a small device size of approximately 500 × 400 µm. This makes this type of filters well suited for application as WDM (de-)multiplexer in silicon photonics transceivers for optical data communication in large scale computer systems.

  12. 73.7 Tb/s (96 x 3 x 256-Gb/s) mode-division-multiplexed DP-16QAM transmission with inline MM-EDFA.

    Science.gov (United States)

    Sleiffer, V A J M; Jung, Y; Veljanovski, V; van Uden, R G H; Kuschnerov, M; Chen, H; Inan, B; Nielsen, L Grüner; Sun, Y; Richardson, D J; Alam, S U; Poletti, F; Sahu, J K; Dhar, A; Koonen, A M J; Corbett, B; Winfield, R; Ellis, A D; de Waardt, H

    2012-12-10

    Transmission of a 73.7 Tb/s (96 x 3 x 256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119 km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6 x 6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz.

  13. Novel secure and bandwidth efficient optical code division multiplexed system for future access networks

    Science.gov (United States)

    Singh, Simranjit

    2016-12-01

    In this paper, a spectrally coded optical code division multiple access (OCDMA) system using a hybrid modulation scheme has been investigated. The idea is to propose an effective approach for simultaneous improvement of the system capacity and security. Data formats, NRZ (non-return to zero), DQPSK (differential quadrature phase shift keying), and PoISk (polarisation shift keying) are used to get the orthogonal modulated signal. It is observed that the proposed hybrid modulation provides efficient utilisation of bandwidth, increases the data capacity and enhances the data confidentiality over existing OCDMA systems. Further, the proposed system performance is compared with the current state-of-the-art OCDMA schemes.

  14. Fast Tunable Wavelength Sources Based on the Laser Diode Array

    Institute of Scientific and Technical Information of China (English)

    Sung-Chan; Cho; Hyun; Ha; Hong; Byoung-Whi; Kim

    2003-01-01

    We report a demonstration of a fast wavelength tunable source (TWS) based on the laser diode array coupled to the arrayed waveguide grating (AWG) multiplexer. The switching and optical characteristics of TWS make it a candidate for implementing the wavelength-division space switch fabric for an optical packet/burst switching.

  15. Double domain wavelength multiplexed Fizeau interferometer with high resolution dynamic sensing and absolute length detection

    Science.gov (United States)

    Antonacci, Julián; Arenas, Gustavo F.; Duchowicz, Ricardo

    2017-04-01

    In this work, we present a simple photonic instrument that has the ability of measuring positions, distances and vibrations with very high resolution by means of two Fizeau interferometers (FI), both using the same optical fiber end as a probe tip itself. On the one hand we have a time domain FI powered with a 1310 nm laser and monitored by an InGaAs detector providing displacement information with resolution around a tenth of nm but regardless of the absolute position of object and of the displacement sense. On the other, a spectral domain FI version based on a super luminescent source (SLED) centred at 800 nm with bandwidth of nearly 40 nm is analysed in real time by means of a digital spectrometer. Each spectrum is acquired in a very small time interval and provides information of both length of the cavity as well as its correct sense of evolution. Resolution of this system is lower than its complementary temporal case, but distance and sense measurements are absolute and can be determined successfully by adequate processing of spectral signal.Both interferometers are optically coupled to a single fiber optic probe and are wavelength modulated.Therefore, combination of both sensors results in a new one which allows the correct knowledge of an object or surfaces under test, i.e. a high resolution of displacement data plus its absolute position and true sense of movement.

  16. Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications

    Science.gov (United States)

    Ren, Yongxiong; Li, Long; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J.; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E.

    2016-09-01

    To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing.

  17. Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications

    CERN Document Server

    Ren, Yongxiong; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E

    2016-01-01

    To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we multiplex and transmit four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam, we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the higher-rate link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the lower rates, a green laser diode is directly modulated. Finally, we s...

  18. Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications

    Science.gov (United States)

    Ren, Yongxiong; Li, Long; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J.; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E.

    2016-01-01

    To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing. PMID:27615808

  19. An algorithm and a Tool for Wavelength Allocation in OMS-SP Ring Architecture

    DEFF Research Database (Denmark)

    Riaz, Muhammad Tahir; Pedersen, Jens Myrup; Madsen, Ole Brun

    2006-01-01

    OMS-SP ring is one of the well known architectures in Wavelength Division Multiplexing based optical fiber networks. The architecture supports a restorable full mesh in an optical fiber ring using multiple light wavelengths. The paper presents an algorithm to allocate wavelengths in the OMS-SP ring...

  20. Design of DPSS based fiber bragg gratings and their application in all-optical encryption, OCDMA, optical steganography, and orthogonal-division multiplexing.

    Science.gov (United States)

    Djordjevic, Ivan B; Saleh, Alaa H; Küppers, Franko

    2014-05-05

    The future information infrastructure will be affected by limited bandwidth of optical networks, high energy consumption, heterogeneity of network segments, and security issues. As a solution to all problems, we advocate the use of both electrical basis functions (orthogonal prolate spheroidal basis functions) and optical basis functions, implemented as FBGs with orthogonal impulse response in addition to spatial modes. We design the Bragg gratings with orthogonal impulse responses by means of discrete layer peeling algorithm. The target impulse responses belong to the class of discrete prolate spheroidal sequences, which are mutually orthogonal regardless of the sequence order, while occupying the fixed bandwidth. We then design the corresponding encoders and decoders suitable for all-optical encryption, optical CDMA, optical steganography, and orthogonal-division multiplexing (ODM). Finally, we propose the spectral multiplexing-ODM-spatial multiplexing scheme enabling beyond 10 Pb/s serial optical transport networks.

  1. Research for application of optical wavelength multiplexing method in electric utility communications networks. Hikarihacho taju hoshiki no denryoku eno tekiyo kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Tohi, T. (The Kasai Electric Power Co. Inc., Osaka (Japan))

    1994-06-25

    A study was made on the optical wavelength multiplexing method (independent signals of different wavelengths are transmitted) as an optical communication method capable of responding to electric utility communications networks, and the SCM method (frequency-multiplexed signals are transmitted, with analog modulation of the optical source). 1.31 and 1.55 [mu]m optical signals were multiplex-transmitted to the 1.31 [mu]m optical network to reveal loss fluctuations of OPGW, and overhead and underground cables. The loss of fusion points was not observed. When 1.55 [mu]m light was transmitted to the existing optical transmission cable, loss and loss fluctuations became large slightly, but the fluctuations caused no particular problem in actual application. SCM multiplexing transmission equipment was test-manufactured, and a demonstration test was conducted on it. Optical transmission/reception level fluctuations, video signal channel S/N characteristics, audio/voice/data channel characteristics were made clear. It was confirmed that the SCM optical transmission equipment was stable in the transmission length of 30km or longer. Both the methods studied are believed to be practically applicable. 13 figs., 2 tabs.

  2. Gigabit Access Passive Optical Network Using Wavelength Division Multiplexing—GigaWaM

    DEFF Research Database (Denmark)

    Iglesias Olmedo, Miguel; Suhr, Lau; Prince, Kamau;

    2014-01-01

    passive optical network (WDM-PON) architecture that can deliver symmetric 1 Gb/s to 64 users over 20 km standard single mode fiber using the L and C bands for down and upstream, respectively. During the course of the project, a number of key enabling technologies were developed including tunable...... transceivers, athermal 50 GHz spaced arrayed waveguide grating multiplexer devices, novel hybridization technologies for integration of passive and active electro-optic devices, and system-level algorithms that ensure the quality of service. The outcome of the project proved a reliable, cost...

  3. Performance comparison of pre-, boost-, and inline-multimode erbium-doped fiber amplifier configurations to boost mode-division multiplexed multimode fiber link

    Science.gov (United States)

    Gupta, Rajan; Kaler, Rajinder Singh

    2016-05-01

    The performance of 3×3, 4×4, 5×5, and 6×6 optical multi-input multioutput (MIMO) mode-division multiplexed multimode fiber (MMF) systems has been investigated using pre-, boost-, and inline-multimode erbium-doped fiber amplifier configuration methods with LPlm (linearly polarized) modes. The outcome of these configurations has been compared in terms of quality factor (Q-factor) and bit error rate (BER). It is reported that inline-configuration provides best results for all MIMO mode-division multiplexing (MDM) systems covering transmission distance of 100 km with acceptable BER (10 dB) over MMF link to boost performance of MDM system.

  4. Quantitative imaging of nanometric optical path length modulations by time-averaged heterodyne holography in coherent frequency-division multiplexing regime

    CERN Document Server

    Bruno, Francois; Lesaffre, Max; Verrier, Nicolas; Atlan, Michael

    2013-01-01

    We report a demonstration of amplitude and phase imaging of out-of-plane sinusoidal vibration at nanometer scales with a heterodyne holographic interferometer. Time-averaged holograms of a phase-modulated optical field are recorded with an exposure time much longer than the modulation period. Optical heterodyning, a frequency-conversion process aimed at shifting a given radiofrequency optical side band in the sensor bandwidth, is performed with an off-axis and frequency-shifted optical local oscillator. The originality of the proposed method is to make use of a multiplexed local oscillator to address several optical side bands into the temporal bandwidth of the sensor array. This process is called coherent frequency-division multiplexing. It enables simultaneous recording and pixel-to-pixel division of two side band holograms, which permits quantitative mapping of the modulation depth of local optical path lengths yielding small optical phase modulations. Additionally, a linear frequency chirp ensures the ret...

  5. A resource-efficient network interface supporting low latency reconfiguration of virtual circuits in time-division multiplexing networks-on-chip

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Bo; Pezzarossa, Luca; Schoeberl, Martin

    2017-01-01

    This paper presents a resource-efficient time-division multiplexing network interface of a network-on- chip intended for use in a multicore platform for hard real-time systems. The network-on-chip pro- vides virtual circuits to move data between core-local on-chip memories. In such a platform......, a change of the application’s operating mode may require reconfiguration of virtual circuits that are setup by the network-on-chip. A unique feature of our network interface is the instantaneous reconfiguration between different time-division multiplexing schedules, containing sets of virtual circuits......, without affecting virtual circuits that persist across the reconfiguration. The results show that the worst-case latency from trigger- ing a reconfiguration until the new schedule is executing, is in the range of 300 clock cycles. Experiments show that new schedules can be transmitted from a single master...

  6. Compressive sensing-based channel bandwidth improvement in optical wireless orthogonal frequency division multiplexing link using visible light emitting diode.

    Science.gov (United States)

    Won, Yong-Yuk; Yoon, Sang Min

    2014-08-25

    A new technique, which can compensate for the lack of channel bandwidth in an optical wireless orthogonal frequency division multiplexing (OFDM) link based on a light emitting diode (LED), is proposed. It uses an adaptive sampling and an inverse discrete cosine transform in order to convert an OFDM signal into a sparse waveform so that not only is the important data obtained efficiently but the redundancy one is removed. In compressive sensing (CS), a sparse signal that is sampled below the Nyquist/Shannon limit can be reconstructed successively with enough measurement. This means that the CS technique can increase the data rate of visible light communication (VLC) systems based on LEDs. It is observed that the data rate of the proposed CS-based VLC-OFDM link can be made 1.7 times greater than a conventional VLC-OFDM link (from 30.72 Mb/s to 51.2 Mb/s). We see that the error vector magnitude (EVM) of the quadrature phase shift keying (QPSK) symbol is 31% (FEC limit: EVM of 32%) at a compression ratio of 40%.

  7. In vitro and in vivo tissue harmonic images obtained with parallel transmit beamforming by means of orthogonal frequency division multiplexing.

    Science.gov (United States)

    Demi, Libertario; Ramalli, Alessandro; Giannini, Gabriele; Mischi, Massimo

    2015-01-01

    In classic pulse-echo ultrasound imaging, the data acquisition rate is limited by the speed of sound. To overcome this, parallel beamforming techniques in transmit (PBT) and in receive (PBR) mode have been proposed. In particular, PBT techniques, based on the transmission of focused beams, are more suitable for harmonic imaging because they are capable of generating stronger harmonics. Recently, orthogonal frequency division multiplexing (OFDM) has been investigated as a means to obtain parallel beamformed tissue harmonic images. To date, only numerical studies and experiments in water have been performed, hence neglecting the effect of frequencydependent absorption. Here we present the first in vitro and in vivo tissue harmonic images obtained with PBT by means of OFDM, and we compare the results with classic B-mode tissue harmonic imaging. The resulting contrast-to-noise ratio, here used as a performance metric, is comparable. A reduction by 2 dB is observed for the case in which three parallel lines are reconstructed. In conclusion, the applicability of this technique to ultrasonography as a means to improve the data acquisition rate is confirmed.

  8. Impairment assessment of orthogonal frequency division multiplexing over dispersion-managed links in backbone and backhaul networks

    Science.gov (United States)

    Tamilarasan, Ilavarasan; Saminathan, Brindha; Murugappan, Meenakshi

    2016-04-01

    The past decade has seen the phenomenal usage of orthogonal frequency division multiplexing (OFDM) in the wired as well as wireless communication domains, and it is also proposed in the literature as a future proof technique for the implementation of flexible resource allocation in cognitive optical networks. Fiber impairment assessment and adaptive compensation becomes critical in such implementations. A comprehensive analytical model for impairments in OFDM-based fiber links is developed. The proposed model includes the combined impact of laser phase fluctuations, fiber dispersion, self phase modulation, cross phase modulation, four-wave mixing, the nonlinear phase noise due to the interaction of amplified spontaneous emission with fiber nonlinearities, and the photodetector noises. The bit error rate expression for the proposed model is derived based on error vector magnitude estimation. The performance analysis of the proposed model is presented and compared for dispersion compensated and uncompensated backbone/backhaul links. The results suggest that OFDM would perform better for uncompensated links than the compensated links due to the negligible FWM effects and there is a need for flexible compensation. The proposed model can be employed in cognitive optical networks for accurate assessment of fiber-related impairments.

  9. On the Efficient Broadcasting of Heterogeneous Services over Band-Limited Channels: Unequal Power Allocation for Wavelet Packet Division Multiplexing

    Directory of Open Access Journals (Sweden)

    Maurizio Murroni

    2008-01-01

    Full Text Available Multiple transmission of heterogeneous services is a central aspect of broadcasting technology. Often, in this framework, the design of efficient communication systems is complicated by stringent bandwidth constraint. In wavelet packet division multiplexing (WPDM, the message signals are waveform coded onto wavelet packet basis functions. The overlapping nature of such waveforms in both time and frequency allows improving the performance over the commonly used FDM and TDM schemes, while their orthogonality properties permit to extract the message signals by a simple correlator receiver. Furthermore, the scalable structure of WPDM makes it suitable for broadcasting heterogeneous services. This work investigates unequal error protection (UEP of data which exhibit different sensitivities to channel errors to improve the performance of WPDM for transmission over band-limited channels. To cope with bandwidth constraint, an appropriate distribution of power among waveforms is proposed which is driven by the channel error sensitivities of the carried message signals in case of Gaussian noise. We address this problem by means of the genetic algorithms (GAs, which allow flexible suboptimal solution with reduced complexity. The mean square error (MSE between the original and the decoded message, which has a strong correlation with subjective perception, is used as an optimization criterion.

  10. Interferometric characterization of few-mode fibers (FMF) for mode-division multiplexing (MDM)

    DEFF Research Database (Denmark)

    Muliar, Olena; Usuga Castaneda, Mario A.; Rottwitt, Karsten;

    2015-01-01

    The rapid growth of global data traffic demands the continuous search for new technologies and systems that could increase transmission capacity in optical links and recent experiments show that to do so, it is advantageous to explore new degrees of freedom such as polarization, wavelength...... requires advanced characterization methods with regard to the modal content of its photonics components and in particular of the fibers involved for data transmission. In this contribution we present a time-domain interferometric technique for a full modal characterization of few mode fibers (FMF...... and a careful evaluation of the resulting interferograms allows us to have full access to key parameters such as number of modes, modal weight, differential time delay between propagating modes and intensity profiles. In this work, we apply this simple and complete characterization method to the case of a short...

  11. High-Capacity Multi-Core Fibers for Space-Division Multiplexing

    DEFF Research Database (Denmark)

    Ye, Feihong

    trench-assisted MCFs (TAMCFs). The traditional approach for TA-MCFs design has relied on numerical simulations, which make deriving relationships between XT and fiber structural parameters difficult and non-intuitive. As it is important to be able to understand the effects of various fiber structural...... of the present SMF-based systems. Among the proposed SDM schemes, the one based on uncoupled multi-core fibers (MCFs) having multiple cores in a mutual cladding has proven effective in substantially increasing the transmission capacity per fiber with least system complexity as demonstrated in several state...... the same refractive index profiles. Based on the model, the XT values in TA-MCFs as well as XT properties, including wavelength-dependent XT, XT reduction amount versus trench width, trench depth and XT dependence on core pitch are easily analyzed. It has also been shown that the XT in MCFs depends...

  12. Prescaled phase-locked loop using phase modulation and spectral filtering and its application to clock extraction from 160-Gbit/s optical-time-division multiplexed signal.

    Science.gov (United States)

    Igarashi, Koji; Katoh, Kazuhiro; Kikuchi, Kazuro

    2006-05-01

    We propose a prescaled phase-locked loop (PLL) using a simple optoelectronic phase comparator based on phase modulation and spectral filtering. Our phase comparator has a high dynamic range of over 9 dB and a high sensitivity comparable to that using an electrical mixer. A PLL composed of our phase comparator enables to extract a low-noise 10-GHz clock from a 160-Gbit/s optical-time-division multiplexed (OTDM) signal.

  13. Analytical bit error rate performance evaluation of an orthogonal frequency division multiplexing power line communication system impaired by impulsive and Gaussian channel noise

    OpenAIRE

    Munshi Mahbubur Rahman; Satya Prasad Majumder

    2015-01-01

    An analytical approach is presented to evaluate the bit error rate (BER) performance of a power line (PL) communication system considering the combined influence of impulsive noise and background PL Gaussian noise. Middleton class-A noise model is considered to evaluate the effect of impulsive noise. The analysis is carried out to find the expression of the signal-to-noise ratio and BER considering orthogonal frequency division multiplexing (OFDM) with binary phase shift keying modulation wit...

  14. Mode-Selective Wavelength Conversion Based on Four-Wave Mixing in a Multimode Silicon Waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2013-01-01

    We report all-optical mode-selective wavelength conversion based on four-wave mixing in a multimode Si waveguide. A two-mode division multiplexing circuit using tapered directional coupler based (de)multiplexers is used for the application. Experimental results show clear eye-diagrams and moderate...

  15. Few-mode vertical-cavity surface-emitting lasers for space-division multiplexing

    Science.gov (United States)

    Su, Yaman; Yu, Lijuan; Guo, Xia; Zhang, Xing; Liu, Jianguo; Zhu, Ninghua

    2017-09-01

    In order to choose the proper radius of oxide aperture for few-mode vertical-cavity surface-emitting lasers (VCSELs), the influences of oxide aperture size on the multi-transverse-mode behaviors are investigated in detail. By establishing the effective refractive index model to simulate VCSELs with different radii of oxide apertures, the wavelength and corresponding order of different modes are obtained. VCSELs with three kinds of oxide apertures are manufactured. Then the multi-transverse-mode spectra and near-field are measured. It is found that when the radius is between 1.5 and 4.5 {{μ }}{{m}}, few-mode VCSELs can be implemented. The 2.5 {{μ }}{{m}} VCSEL manufactured in this paper only emits LP01 mode and LP21 mode. Since the space distance between the two modes is 2 {{μ }}{{m}}, it is expected to realize direct-modulation few-mode VCSELs by channel etching or ion implantation between the two modes. Project supported by the National Basic Research Program of China (No. 2014CB3400102), the National Natural Science Foundation of China (No. 61335004), the National High Technology Research and Development Program of China (No. 2015AA017101), and the National Key Technologies R & D Program of China (No. 2016YFB0400603).

  16. Switchable in-line monitor for multi-dimensional multiplexed photonic integrated circuit.

    Science.gov (United States)

    Chen, Guanyu; Yu, Yu; Ye, Mengyuan; Zhang, Xinliang

    2016-06-27

    A flexible monitor suitable for the discrimination of on-chip transmitted mode division multiplexed (MDM) and wavelength division multiplexed (WDM) signals is proposed and fabricated. By selectively extracting part of the incoming signals through the tunable wavelength and mode dependent drop filter, the in-line and switchable monitor can discriminate the wavelength, mode and power information of the transmitted signals. Being different from a conventional mode and wavelength demultiplexer, the monitor is specifically designed to ensure a flexible in-line monitoring. For demonstration, three mode and three wavelength multiplexed signals are successfully processed. Assisted by the integrated photodetectors (PDs), both the measured photo currents and eye diagrams validate the performance of the proposed device. The bit error ratio (BER) measurement results show less than 0.4 dB power penalty between different modes and ~2 dB power penalty for single wavelength and WDM cases under 10-9 BER level.

  17. Evaluation and Design Space Exploration of a Time-Division Multiplexed NoC on FPGA for Image Analysis Applications

    Directory of Open Access Journals (Sweden)

    Houzet Dominique

    2009-01-01

    Full Text Available Abstract The aim of this paper is to present an adaptable Fat Tree NoC architecture for Field Programmable Gate Array (FPGA designed for image analysis applications. Traditional Network on Chip (NoC is not optimal for dataflow applications with large amount of data. On the opposite, point-to-point communications are designed from the algorithm requirements but they are expensives in terms of resource and wire. We propose a dedicated communication architecture for image analysis algorithms. This communication mechanism is a generic NoC infrastructure dedicated to dataflow image processing applications, mixing circuit-switching and packet-switching communications. The complete architecture integrates two dedicated communication architectures and reusable IP blocks. Communications are based on the NoC concept to support the high bandwidth required for a large number and type of data. For data communication inside the architecture, an efficient time-division multiplexed (TDM architecture is proposed. This NoC uses a Fat Tree (FT topology with Virtual Channels (VCs and flit packet-switching with fixed routes. Two versions of the NoC are presented in this paper. The results of their implementations and their Design Space Exploration (DSE on Altera Stratix II are analyzed and compared with a point-to-point communication and illustrated with a multispectral image application. Results show that a point-to-point communication scheme is not efficient for large amount of multispectral image data communications. An NoC architecture uses only 10% of the memory blocks required for a point-to-point architecture but seven times more logic elements. This resource allocation is more adapted to image analysis algorithms as memory elements are a critical point in embedded architectures. An FT NoC-based communication scheme for data transfers provides a more appropriate solution for resource allocation.

  18. Evaluation and Design Space Exploration of a Time-Division Multiplexed NoC on FPGA for Image Analysis Applications

    Directory of Open Access Journals (Sweden)

    Dominique Houzet

    2009-01-01

    Full Text Available The aim of this paper is to present an adaptable Fat Tree NoC architecture for Field Programmable Gate Array (FPGA designed for image analysis applications. Traditional Network on Chip (NoC is not optimal for dataflow applications with large amount of data. On the opposite, point-to-point communications are designed from the algorithm requirements but they are expensives in terms of resource and wire. We propose a dedicated communication architecture for image analysis algorithms. This communication mechanism is a generic NoC infrastructure dedicated to dataflow image processing applications, mixing circuit-switching and packet-switching communications. The complete architecture integrates two dedicated communication architectures and reusable IP blocks. Communications are based on the NoC concept to support the high bandwidth required for a large number and type of data. For data communication inside the architecture, an efficient time-division multiplexed (TDM architecture is proposed. This NoC uses a Fat Tree (FT topology with Virtual Channels (VCs and flit packet-switching with fixed routes. Two versions of the NoC are presented in this paper. The results of their implementations and their Design Space Exploration (DSE on Altera Stratix II are analyzed and compared with a point-to-point communication and illustrated with a multispectral image application. Results show that a point-to-point communication scheme is not efficient for large amount of multispectral image data communications. An NoC architecture uses only 10% of the memory blocks required for a point-to-point architecture but seven times more logic elements. This resource allocation is more adapted to image analysis algorithms as memory elements are a critical point in embedded architectures. An FT NoC-based communication scheme for data transfers provides a more appropriate solution for resource allocation.

  19. Simultaneous polarization-insensitive phase-space trans-multiplexing and wavelength multicasting via cross-phase modulation in a photonic crystal fiber at 10 GBd

    Science.gov (United States)

    Cannon, Brice M.

    This thesis investigates the all-optical combination of amplitude and phase modulated signals into one unified multi-level phase modulated signal, utilizing the Kerr nonlinearity of cross-phase modulation (XPM). Predominantly, the first experimental demonstration of simultaneous polarization-insensitive phase-transmultiplexing and multicasting (PI-PTMM) will be discussed. The PI-PTMM operation combines the data of a single 10-Gbaud carrier-suppressed return-to-zero (CSRZ) on-off keyed (OOK) pump signal and 4x10-Gbaud return-to-zero (RZ) binary phase-shift keyed (BPSK) probe signals to generate 4x10-GBd RZ-quadrature phase-shift keyed (QPSK) signals utilizing a highly nonlinear, birefringent photonic crystal fiber (PCF). Since XPM is a highly polarization dependent nonlinearity, a polarization sensitivity reduction technique was used to alleviate the fluctuations due to the remotely generated signals' unpredictable states of polarization (SOP). The measured amplified spontaneous emission (ASE) limited receiver sensitivity optical signal-to-noise ratio (OSNR) penalty of the PI-PTMM signal relative to the field-programmable gate array (FPGA) pre-coded RZ-DQPSK baseline at a forward-error correction (FEC) limit of 10-3 BER was ≈ 0.3 dB. In addition, the OSNR of the remotely generated CSRZ-OOK signal could be degraded to ≈ 29 dB/0.1nm, before the bit error rate (BER) performance of the PI-PTMM operation began to exponentially degrade. A 138-km dispersion-managed recirculating loop system with a 100-GHz, 13-channel mixed-format dense-wavelength-division multiplexed (DWDM) transmitter was constructed to investigate the effect of metro/long-haul transmission impairments. The PI-PTMM DQPSK and the FPGA pre-coded RZ-DQPSK baseline signals were transmitted 1,900 km and 2,400 km in the nonlinearity-limited transmission regime before reaching the 10-3 BER FEC limit. The relative reduction in transmission distance for the PI-PTMM signal was due to the additional transmitter

  20. Polymeric 32-channel arrayed waveguide grating multiplexer using fluorinated poly (ether ether ketone)

    Institute of Scientific and Technical Information of China (English)

    Fei Wang(王菲); Wei Sun(孙伟); Aize Li(李艾泽); Maobin Yi(衣茂斌); Zhenhua Jiang(姜振华); Daming Zhang(张大明)

    2004-01-01

    In wavelength division multiplexing (WDM) systems, an arrayed waveguide grating (AWG) multiplexer is a key component. A polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated poly (ether ether ketone)(FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the Polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8nm and a center wavelength of 1548 nm in the room temperature.

  1. Experimental demonstration of subcarrier multiplexed quantum key distribution system.

    Science.gov (United States)

    Mora, José; Ruiz-Alba, Antonio; Amaya, Waldimar; Martínez, Alfonso; García-Muñoz, Víctor; Calvo, David; Capmany, José

    2012-06-01

    We provide, to our knowledge, the first experimental demonstration of the feasibility of sending several parallel keys by exploiting the technique of subcarrier multiplexing (SCM) widely employed in microwave photonics. This approach brings several advantages such as high spectral efficiency compatible with the actual secure key rates, the sharing of the optical fainted pulse by all the quantum multiplexed channels reducing the system complexity, and the possibility of upgrading with wavelength division multiplexing in a two-tier scheme, to increase the number of parallel keys. Two independent quantum SCM channels featuring a sifted key rate of 10 Kb/s/channel over a link with quantum bit error rate <2% is reported.

  2. Three-mode mode-division-multiplexing passive optical network over 12-km low mode-crosstalk FMF using all-fiber mode MUX/DEMUX

    Science.gov (United States)

    Ren, Fang; Li, Juhao; Wu, Zhongying; Hu, Tao; Yu, Jinyi; Mo, Qi; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

    2017-01-01

    We propose three-mode mode-division-multiplexing passive optical network (MDM-PON) based on low mode-crosstalk few-mode fiber (FMF) and all-fiber mode multiplexer/demultiplexer (MUX/DEMUX). The FMF with step-index profile is designed and fabricated for effectively three-independent-spatial-mode transmission and low mode-crosstalk for MDM-PON transmission. The all-fiber mode MUX/DEMUX are composed of cascaded mode selective couplers (MSCs), which simultaneously multiplex or demultiplex multiple modes. Based on the low mode-crosstalk of the FMF and all-fiber mode MUX/DEMUX, each optical network unit (ONU) communicates with the optical line terminal (OLT) independently utilizing a different optical linearly polarized (LP) spatial mode in MDM-PON system. We experimentally demonstrate MDM-PON transmission of three independent-spatial-modes over 12-km FMF with 10-Gb/s optical on-off keying (OOK) signal and direct detection.

  3. ANALYSIS OF REDUCTION IN COMPLEXITY OF MULTIPLE INPUT- MULTIPLE OUTPUT-ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEMS WITH CARRIER FREQUENCY OFFSET ESTIMATION AND CORRECTION

    Directory of Open Access Journals (Sweden)

    Sabitha Gauni

    2014-01-01

    Full Text Available Orthogonal Frequency Division Multiplexing (OFDM is a promising research area in Wireless Communication for high data rates. The Multiple Input-Multiple Output (MIMO technology when incorporated with the OFDM system promise a significant boost in the performance. But, the MIMO-OFDM systems are very sensitive to Carrier Frequency Offset (CFO as it deteriorates the system performance with the rise of Inter-Carrier-Interference (ICI. A theoretical analysis to evaluate the performance of Orthogonal Frequency Division Multiplexing (OFDM systems is done here, under the combined influence of Phase Offset and Frequency Offset over Rayleigh, Weibull and Nakagami fading channels using Binary Phase Shift Keying (BPSK Modulation. The analysis of increase in Bit Error Rate (BER caused by the presence of Phase Offset and Frequency Offset is evaluated assuming Gaussian probability density function. Hence the estimation and correction of CFO plays a vital role in MIMO-OFDM systems. A method for CFO estimation and correction is analyzed in the MIMO-OFDM system with 16-QAM modulation. In non-pilot-aided systems the CFO acquisition is done using Maximum Likelihood Estimation (MLE algorithm. The proposed scheme uses the same block for CFO correction of MIMO-OFDM symbols. Since the same phase calculation block is used for the ML estimation along with the acquisition, the computational cost and the complexity of implementation is reduced.

  4. Design of a pulse-triggered four-channel functional electrical stimulator using complementary current source and time division multiplexing output method.

    Science.gov (United States)

    Wang, Hai-Peng; Wang, Zhi-Gong; Lü, Xiao-Ying; Huang, Zong-Hao; Zhou, Yu-Xuan

    2015-08-01

    In this paper, a four-channel pulse-triggered functional electrical stimulator using complementary current source and time division output method is proposed for the research and application of functional electrical stimulation (FES). The high-voltage compliance and output impedance is increased by adopting the complementary current source, which can also realize the linear voltage-to-current conversion and high channel isolation. A high-voltage analog switch chip MAX14803, combined with a FIFO queue algorithm in the microprocessor, is used to setup the H-bridge and multiplexers for the four-channel time division multiplexing output. With this method, the size and cost of the key components are reduced greatly. The stimulating core circuit area is 30 × 50 mm(2). According to the experiments, the stimulator can achieve the four-channel charge-balanced biphasic stimulation with a current range between 0 and 60 mA and a single-phase pulse amplitude up to 60 V.

  5. On-chip noninterference angular momentum multiplexing of broadband light.

    Science.gov (United States)

    Ren, Haoran; Li, Xiangping; Zhang, Qiming; Gu, Min

    2016-05-13

    Angular momentum division has emerged as a physically orthogonal multiplexing method in high-capacity optical information technologies. However, the typical bulky elements used for information retrieval from the overall diffracted field, based on the interference method, impose a fundamental limit toward realizing on-chip multiplexing. We demonstrate noninterference angular momentum multiplexing by using a mode-sorting nanoring aperture with a chip-scale footprint as small as 4.2 micrometers by 4.2 micrometers, where nanoring slits exhibit a distinctive outcoupling efficiency on tightly confined plasmonic modes. The nonresonant mode-sorting sensitivity and scalability of our approach enable on-chip parallel multiplexing over a bandwidth of 150 nanometers in the visible wavelength range. The results offer the possibility of ultrahigh-capacity and miniaturized nanophotonic devices harnessing angular momentum division.

  6. Five wavelength DFB fiber lase source

    DEFF Research Database (Denmark)

    Varming, Poul; Hübner, Jörg; Kristensen, M.

    1997-01-01

    Stable single-mode laser sources with narrow linewidth are key components in high-capacity wavelength-division multiplexed (WDM) optical communication systems. Distributed feedback (DFB) and distributed Bragg reflection (DBR) fiber lasers are compact devices, which are able to provide stable single......-mode operation. They are inherently fiber compatible and cascadable. We present a multiwavelength laser source consisting of five fiber DFB lasers spliced together and pumped by a single 60-mW 1480-nm semiconductor laser...

  7. PERFORMANCE ANALYSIS OF DISCRETE WAVELET TRANSFORM BASED MULTIPLE INPUT MULTIPLE OUTPUT ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM FOR DIFFERENT WAVELETS IN DIFFERENT CHANNEL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    HariprasadNagarajan

    2013-01-01

    Full Text Available Multiple Input Multiple Output (MIMO and Orthogonal Frequency Division Multiplexing (OFDM are the two assuring technologies that offers high data rate as required for the 4G wireless systems. Conventionally OFDM is Fast Fourier Transform (FFT based system. It uses IFFT (Inverse FFT blocks in the transmitter and FFT blocks in the receiver. OFDM combined with MIMO gives increased throughput and better system performance and hence FFT based MIMO OFDM systems are widely used in 4G wireless schemes. Recent researches shows that replacing the FFT with Discrete Wavelet Transform (DWT the system performance can be further improved. This leads to a new scenario DWT based MIMO OFDM system. In this study one such system is simulated and the Bit Error Rate (BER performance of the system is analysed for the different types of wavelets under different channel environments.

  8. Design of eight-mode polarization-maintaining few-mode fiber for multiple-input multiple-output-free spatial division multiplexing.

    Science.gov (United States)

    Wang, Lixian; LaRochelle, Sophie

    2015-12-15

    We propose a polarization-maintaining few-mode fiber (FMF) that features an elliptical ring shaped core with a high refractive index contrast ∼0.03 between the core and the cladding. This fiber design alleviates the usual trade-off between the number of guided modes and the achievable birefringence that is usually observed in conventional elliptical-core FMFs. Through numerical simulations, we show that this fiber design can support up to 10 guided vector modes over the entire C band while providing large birefringence. Except for the two fundamental modes, the eight higher-order vector modes are all separated from their adjacent modes by effective index differences >10⁻⁴, which is the typical birefringence value of single-mode polarization maintaining fibers. The designed fiber targets applications in spatial division multiplexing of optical channels, without multiple-input-multiple-output (MIMO) digital signal processing, for short-reach optical interconnects.

  9. Investigation of adaptive filtering and MDL mitigation based on space-time block-coding for spatial division multiplexed coherent receivers

    Science.gov (United States)

    Weng, Yi; He, Xuan; Yao, Wang; Pacheco, Michelle C.; Wang, Junyi; Pan, Zhongqi

    2017-07-01

    In this paper, we explored the performance of space-time block-coding (STBC) assisted multiple-input multiple-output (MIMO) scheme for modal dispersion and mode-dependent loss (MDL) mitigation in spatial-division multiplexed optical communication systems, whereas the weight matrices of frequency-domain equalization (FDE) were updated heuristically using decision-directed recursive least squares (RLS) algorithm for convergence and channel estimation. The proposed STBC-RLS algorithm can achieve 43.6% enhancement on convergence rate over conventional least mean squares (LMS) for quadrature phase-shift keying (QPSK) signals with merely 16.2% increase in hardware complexity. The overall optical signal to noise ratio (OSNR) tolerance can be improved via STBC by approximately 3.1, 4.9, 7.8 dB for QPSK, 16-quadrature amplitude modulation (QAM) and 64-QAM with respective bit-error-rates (BER) and minimum-mean-square-error (MMSE).

  10. Fast-synchronization and low-timing-jitter self-clocking concept for 160 Gbit/s optical time-division multiplexing transmissions.

    Science.gov (United States)

    Zhang, Shangjian; Gomez-Agis, Fausto; Liu, Yong; Calabretta, Nicola; Tangdiongga, Eduward; Dorren, Harm J S

    2010-01-01

    We propose a self-clocking method based on in-band clock pilot insertion at the transmission data signal. The method can achieve clock recovery without the need for an ultrafast phase comparator and a phase-locked loop in the receiver. We demonstrate fast synchronization, low timing jitter, and a highly stable recovered clock from a 160 Gbit/s optical time-division multiplexing data signal after a 51 km fiber transmission. The recovered clock shows no patterning effect with a clock dynamic range of 10 dB for error-free operation of 160 to 40 Gbit/s demultiplexing with a power penalty of 1.1 dB.

  11. An auxiliary graph based dynamic traffic grooming algorithm in spatial division multiplexing enabled elastic optical networks with multi-core fibers

    Science.gov (United States)

    Zhao, Yongli; Tian, Rui; Yu, Xiaosong; Zhang, Jiawei; Zhang, Jie

    2017-03-01

    A proper traffic grooming strategy in dynamic optical networks can improve the utilization of bandwidth resources. An auxiliary graph (AG) is designed to solve the traffic grooming problem under a dynamic traffic scenario in spatial division multiplexing enabled elastic optical networks (SDM-EON) with multi-core fibers. Five traffic grooming policies achieved by adjusting the edge weights of an AG are proposed and evaluated through simulation: maximal electrical grooming (MEG), maximal optical grooming (MOG), maximal SDM grooming (MSG), minimize virtual hops (MVH), and minimize physical hops (MPH). Numeric results show that each traffic grooming policy has its own features. Among different traffic grooming policies, an MPH policy can achieve the lowest bandwidth blocking ratio, MEG can save the most transponders, and MSG can obtain the fewest cores for each request.

  12. Physical-layer energy-efficient receiving method based on selective sampling in orthogonal frequency division multiplexing access passive optical network

    Science.gov (United States)

    Li, Jun; He, Hao; Bi, Meihua; Hu, Weisheng

    2014-05-01

    We propose a physical-layer energy-efficient receiving method based on selective sampling in an orthogonal frequency division multiplexing access passive optical network (OFDMA-PON). By using the special designed frame head, the receiver within an optical network unit (ONU) can identify the destination of the incoming frame. The receiver only samples at the time when the destination is in agreement with the ONU, while it stays in standby during the rest of the time. We clarify its feasibility through an experiment and analyze the downstream traffic delay by simulation. The results indicate that under limited delay conditions, ˜60% energy can be saved compared with the traditional receiving method in the OFDMA-PON system with 512 ONUs.

  13. Energy-efficient orthogonal frequency division multiplexing-based passive optical network based on adaptive sleep-mode control and dynamic bandwidth allocation

    Science.gov (United States)

    Zhang, Chongfu; Xiao, Nengwu; Chen, Chen; Yuan, Weicheng; Qiu, Kun

    2016-02-01

    We propose an energy-efficient orthogonal frequency division multiplexing-based passive optical network (OFDM-PON) using adaptive sleep-mode control and dynamic bandwidth allocation. In this scheme, a bidirectional-centralized algorithm named the receiver and transmitter accurate sleep control and dynamic bandwidth allocation (RTASC-DBA), which has an overall bandwidth scheduling policy, is employed to enhance the energy efficiency of the OFDM-PON. The RTASC-DBA algorithm is used in an optical line terminal (OLT) to control the sleep mode of an optical network unit (ONU) sleep and guarantee the quality of service of different services of the OFDM-PON. The obtained results show that, by using the proposed scheme, the average power consumption of the ONU is reduced by ˜40% when the normalized ONU load is less than 80%, compared with the average power consumption without using the proposed scheme.

  14. Routing and wavelength assignment in hierarchical WDM networks

    Institute of Scientific and Technical Information of China (English)

    Yiyi LU; Ruxiang JIN; Chen HE

    2008-01-01

    A new routing and wavelength assignment method applied in hierarchical wavelength division multiplexing(WDM)networks is proposed.The algorithm is called offiine band priority algorithm(offiine BPA).The offline BPA targets to maximize the number of waveband paths under the condition of minimum number of wavelengths,and solve the routing and wavelength assignment(RWA)problem with waveband grooming to reduce cost.Based on the circle construction algorithm,waveband priority function is introduced to calculate the RWA problem.Simulation results demonstrate that the proposed algorithm achieves significant cost reduction in WDM network construction.

  15. Experimental demonstration of wavelength domain rogue-free ONU based on wavelength-pairing for TDM/WDM optical access networks.

    Science.gov (United States)

    Lee, Jie Hyun; Park, Heuk; Kang, Sae-Kyoung; Lee, Joon Ki; Chung, Hwan Seok

    2015-11-30

    In this study, we propose and experimentally demonstrate a wavelength domain rogue-free ONU based on wavelength-pairing of downstream and upstream signals for time/wavelength division-multiplexed optical access networks. The wavelength-pairing tunable filter is aligned to the upstream wavelength channel by aligning it to one of the downstream wavelength channels. Wavelength-pairing is implemented with a compact and cyclic Si-AWG integrated with a Ge-PD. The pairing filter covered four 100 GHz-spaced wavelength channels. The feasibility of the wavelength domain rogue-free operation is investigated by emulating malfunction of the misaligned laser. The wavelength-pairing tunable filter based on the Si-AWG blocks the upstream signal in the non-assigned wavelength channel before data collision with other ONUs.

  16. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide.

    Science.gov (United States)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan; Peucheret, Christophe

    2014-01-13

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due to phase mismatch. A two-mode division multiplexing circuit with tapered directional coupler based (de)multiplexers and a multimode waveguide is designed and fabricated for this application. Experimental results show clear eye-diagrams and moderate power penalties for the wavelength conversion of both modes.

  17. Wavelength Filters in Fibre Optics

    CERN Document Server

    Venghaus, Herbert

    2006-01-01

    Wavelength filters constitute an essential element of fibre-optic networks. This book gives a comprehensive account of the principles and applications of such filters, including their technological realisation. After an introductory chapter on wavelength division multiplexing in current and future fibre optic networks follows a detailed treatment of the phase characteristics of wavelength filters, a factor frequently neglected but of significant importance at high bit rates. Subsequent chapters cover three-dimensional reflection of gratings, arrayed waveguide gratings, fibre Bragg gratings, Fabry-Perot filters, dielectric multilayer filters, ring filters, and interleavers. The book explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. It also includes in-depth information on the characteristics of both commercially available devices and those still at the R&D stage. All chapters are authored by inter...

  18. Design and analysis of O-S-C triple band wavelength division demultiplexer using cascaded MMI couplers

    Science.gov (United States)

    Chack, Devendra; Kumar, V.; Raghuwanshi, Sanjeev Kumar; Singh, Dev Prakash

    2017-01-01

    Compact triple O-S-C band wavelength demultiplexer, which consists of series cascaded multimode interference (MMI) couplers has been carried out in this paper. The MMI coupler has been used to drop the wavelengths of 1510 nm and 1550 nm at bar port while the wavelength 1300 nm into the cross port. Then another MMI coupler has been designed to separate the wavelength 1510 nminto one port and wavelength 1550 nm into another port. The triple wavelength demultiplexer function has been performed by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of MMI coupler. Numerical simulation with finite difference beam propagation method (BPM) has been utilized to design and optimize the operation of the proposed triple wavelength demultiplexer. The simulation results show that insertion losses of wavelength O, S and C, bands are 1.884 dB, 1.452 dB and 2.568 dB, respectively, with isolations for each output waveguide ranging from 10 dB to 28.72 dB. The 3-dB bandwidth of insertion loss for 1300 nm, 1510 nm and 1550 nm are 80 nm, 20 nm and 10 nm, respectively.

  19. Implementasi dan Evaluasi Kinerja Multi Input SingleOutput Orthogonal Frequency Division Multiplexing (MISO OFDM Menggunakan Wireless Open Access Research Platform (WARP

    Directory of Open Access Journals (Sweden)

    Galih Permana Putra

    2017-01-01

    Full Text Available Teknologi komunikasi nirkabel terus berkembang untuk memenuhi kebutuhan manusia akan koneksi informasi yang cepat, pengiriman data yang berkapasitas besar dan dapat diandalkan. Di dalam proses tersebut banyak sekali gangguan yang dapat mempengaruhi penurunan kinerja komunikasi diantaranya adalah multipath fading [1]. Multi Input Single Output (MISO merupakan salah satu teknik space diversity yang menggunakan banyak antena dengan tujuan untuk mengatasi multipath fading. Adapun pada proses transmisi digunakan teknik Orthogonal Frequency-Division Multiplexing (OFDM yang bertujuan memberikan keuntungan dalam hal efisiensi pada saat transmisi data dan mampu menghindari Inter Simbol Interference (ISI. Pada penelitian ini akan dibandingkan kinerja sistem MISO OFDM dan SISO OFDM yang akan disimulasikan dan di implementasikan pada modul Wireless Open Access Penelitian Platform (WARP untuk mengevaluasi kinerja BER sebagai fungsi dari daya pancar dan jarak variasi. Parameter yang digunakan di dalam pengukuran berdasarkan IEEE 802.11 a/g karena menggunakan frekuensi 2,4 Ghz. Terdapat dua skema pengukuran yaitu SISO OFDM dan MISO OFDM dengan variasi jarak 4,6 dan 8 meter dengan variasi daya pancar -35 s/d -4 dBm dengan peningkatan gain 5 kali secara berkala. Dari dua skema yang dilaksanakan dapat disimpulkan bahwa semakin jauh jarak antara pemancar dan penerima maka dibutuhkan penambahan gain untuk menjaga kualitas data yang dikirimkan. Disamping itu, terdapat perbedaan nilai gain untuk mencapai nilai BER = dibutuhkan penambahan gain = - 33 sedangkan pada SISO OFM dibutuhkan penambahan gain = -18.

  20. Stage-dependent minimum bit resolution maps of full-parallel pipelined FFT/IFFT architectures incorporated in real-time optical orthogonal frequency division multiplexing transceivers

    Directory of Open Access Journals (Sweden)

    Junjie Zhang

    2014-08-01

    Full Text Available Fast Fourier transform (FFT and inverse FFT (IFFT are the fundamental algorithms at the heart of optical orthogonal frequency division multiplexing (OOFDM transceivers. The high digital signal processing (DSP complexity has become one of the most significant obstacles to experimentally demonstrating real-time high-capacity OOFDM transceivers. In this study, extensive numerical explorations are undertaken, for the first time, of the impacts of each individual transceiver DSP element on the inverse error vector magnitude (IEVM performance of the OOFDM transceivers incorporating full-parallel pipelined FFT/IFFT architectures. More importantly, FFT/IFFT stage-dependent minimum bit resolution maps are identified, based on which minimum bit resolutions of individual DSP elements of various FFT/IFFT stages can be easily selected according to chosen analogue-to-digital converter/digital-to-analogue converter resolutions. The validity and high accuracy of the identified maps are experimentally verified in field programmable gate array (FPGA-based platforms. In addition to great ease of practical OOFDM transceiver designs, the maps also significantly reduce the FPGA logic resource usage without degrading the overall transceiver IEVM performance.

  1. Combined peak-to-average power ratio reduction and physical layer security enhancement in optical orthogonal frequency division multiplexing visible-light communication systems

    Science.gov (United States)

    Wang, Zhongpeng; Chen, Shoufa

    2016-07-01

    A physical encryption scheme for discrete Hartley transform (DHT) precoded orthogonal frequency division multiplexing (OFDM) visible-light communication (VLC) systems using frequency domain chaos scrambling is proposed. In the scheme, the chaos scrambling, which is generated by a modified logistic mapping, is utilized to enhance the physical layer of security, and the DHT precoding is employed to reduce of OFDM signal for OFDM-based VLC. The influence of chaos scrambling on peak-to-average power ratio (PAPR) and bit error rate (BER) of systems is studied. The experimental simulation results prove the efficiency of the proposed encryption method for DHT-precoded, OFDM-based VLC systems. Furthermore, the influence of the proposed encryption to the PAPR and BER of systems is evaluated. The experimental results show that the proposed security scheme can protect the DHT-precoded, OFDM-based VLC from eavesdroppers, while keeping the good BER performance of DHT-precoded systems. The BER performance of the encrypted and DHT-precoded system is almost the same as that of the conventional DHT-precoded system without encryption.

  2. Analytical bit error rate performance evaluation of an orthogonal frequency division multiplexing power line communication system impaired by impulsive and Gaussian channel noise

    Directory of Open Access Journals (Sweden)

    Munshi Mahbubur Rahman

    2015-02-01

    Full Text Available An analytical approach is presented to evaluate the bit error rate (BER performance of a power line (PL communication system considering the combined influence of impulsive noise and background PL Gaussian noise. Middleton class-A noise model is considered to evaluate the effect of impulsive noise. The analysis is carried out to find the expression of the signal-to-noise ratio and BER considering orthogonal frequency division multiplexing (OFDM with binary phase shift keying modulation with coherent demodulation of OFDM sub-channels. The results are evaluated numerically considering the multipath transfer function model of PL with non-flat power spectral density of PL background noise over a bandwidth of 0.3–100 MHz. The results are plotted for several system and noise parameters and penalty because of impulsive noise is determined at a BER of 10^−6. The computed results show that the system suffers significant power penalty because of impulsive noise which is higher at higher channel bandwidth and can be reduced by increasing the number of OFDM subcarriers to some extent. The analytical results conform well with the simulation results reported earlier.

  3. Novel discretely tunable narrow linewidth fiber laser with uniform wavelength spacing

    Institute of Scientific and Technical Information of China (English)

    Xiaopeng Dong; Yong Chen

    2007-01-01

    A novel configuration of the tunable fiber laser with uniform wavelength spacing in dense wavelength division multiplexing (DWDM) application is proposed. The ring type tunable fiber laser consists of an all-fiber comb filter which determines the wavelength spacing, and a piece of adjustable fiber grating to select the discrete lasing wavelength for WDM application. The proposed all-fiber ring type tunable laser has potential application in the DWDM and other optical systems due to its advantages such as narrow linewidth, easy tuning, uniform wavelength interval, etc..

  4. EW WEIGHT DEPENDENT ROUTING AND WAVELENGTH ASSIGNMENT STRATEGY FOR ALL OPTICAL NETWORKS IN ABSENCE OF WAVELENGTH CONVERTERS

    Directory of Open Access Journals (Sweden)

    Shilpa S. Patil

    2015-09-01

    Full Text Available In wavelength division multiplexed all optical networks; lightpath establishes a connection between sending and receiving nodes bypassing the electronic processing at intermediate nodes. One of the prime objectives of Routing and Wavelength Assignment (RWA problem is to maximize the number of connections efficiently by choosing the best routes. Although there are several algorithms available, improving the blocking performance in optical networks and finding optimal solutions for RWA problem has still remained a challenging issue. Wavelength conversion can be helpful in restricting the problem of wavelength continuity constraint but it increases complexity in the network. In this paper, we propose new weight dependent routing and wavelength assignment strategy for all optical networks without use of wavelength converters. Proposed weight function reduces blocking probability significantly, improving the network performance at various load conditions. Further, due to absence of wavelength converters, the cost and complexity of network reduces. Results show that the proposed strategy performs better than earlier reported methods.

  5. A Comparative Study of Multiplexing Schemes for Next Generation Optical Access Networks

    Science.gov (United States)

    Imtiaz, Waqas A.; Khan, Yousaf; Shah, Pir Mehar Ali; Zeeshan, M.

    2014-09-01

    Passive optical network (PON) is a high bandwidth, economical solution which can provide the necessary bandwidth to end-users. Wavelength division multiplexed passive optical networks (WDM PONs) and time division multiplexed passive optical networks (TDM PONs) are considered as an evolutionary step for next-generation optical access (NGOA) networks. However they fail to provide highest transmission capacity, efficient bandwidth access, and robust dispersion tolerance. Thus future PONs are considered on simpler, efficient and potentially scalable, optical code division multiplexed (OCDM) PONs. This paper compares the performance of existing PONs with OCDM PON to determine a suitable scheme for NGOA networks. Two system parameter are used in this paper: fiber length, and bit rate. Performance analysis using Optisystem shows that; for a sufficient system performance parameters i.e. bit error rate (BER) ≤ 10-9, and maximum quality factor (Q) ≥ 6, OCDMA PON efficiently performs upto 50 km with 10 Gbit/s per ONU.

  6. Wavelength dimensioning for wavelength-routed WDM satellite network

    Institute of Scientific and Technical Information of China (English)

    Liu Zhe; Guo Wei; Deng Changlin; Hu Weisheng

    2016-01-01

    Internet and broadband applications driven by data traffic demand have become key dri-vers for satellite constellations. The key technology to satisfy the high capacity requirements between satellites is optical satellite networks by means of wavelength division multiplexing inter-satellite links (ISLs) with wavelength routing (WDM-OSN). Due to the limited optical amplifier bandwidth onboard the satellite, it is important to minimize the wavelength requirements to provi-sion requests. However, ISLs should be dynamically established and deleted for each satellite according to its visible satellites. Furthermore, different link assignments will result in different topologies, hence yielding different routings and wavelength assignments. Thus, a perfect match model-based link assignment scheme (LAS-PMM) is proposed to design an appropriate topology such that shorter path could be routed and less wavelengths could be assigned for each ISL along the path. Finally, simulation results show that in comparison to the regular Manhattan street net-work (MSN) topology, wavelength requirements and average end-to-end delay based on the topol-ogy generated by LAS-PMM could be reduced by 24.8%and 12.4%, respectively.

  7. WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Mikkelsen, Benny; Jørgensen, Bo Foged

    1998-01-01

    set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect......Optical transport layers need rearrangeable wavelength-division multiplexing optical cross-connects (OXCs) to increase the capacity and flexibility of the network. It has previously been shown that a cross-connect based on all-optical wavelength converters for routing as well as wavelength slot...... interchanging can be used to create a robust and nonblocking OXC. However, for an OXC with n fiber inlets each carrying m wavelengths the OXC requires n×m internal wavelengths, which constrains the size of the cross-connect. In this paper we therefore propose and demonstrate an architecture that uses a reduced...

  8. New all-optical wavelength auto-router based on spatial solitons.

    Science.gov (United States)

    Wu, Yaw-Dong

    2004-09-06

    We propose a novel all-optical wavelength auto-router based on spatial solitons. By using the swing effect of spatial solitons in a Kerr-type nonlinear medium, the proposed nonlinear waveguide structure could function as a self-routing wavelength division multiplexer (WDM). It could be a potential key component in the applications of ultra-high-speed and ultra-high-capacity optical communications and optical data processing systems.

  9. Advanced and flexible multi-carrier receiver architecture for high-count multi-core fiber based space division multiplexed applications

    Science.gov (United States)

    Asif, Rameez

    2016-06-01

    Space division multiplexing (SDM), incorporating multi-core fibers (MCFs), has been demonstrated for effectively maximizing the data capacity in an impending capacity crunch. To achieve high spectral-density through multi-carrier encoding while simultaneously maintaining transmission reach, benefits from inter-core crosstalk (XT) and non-linear compensation must be utilized. In this report, we propose a proof-of-concept unified receiver architecture that jointly compensates optical Kerr effects, intra- and inter-core XT in MCFs. The architecture is analysed in multi-channel 512 Gbit/s dual-carrier DP-16QAM system over 800 km 19-core MCF to validate the digital compensation of inter-core XT. Through this architecture: (a) we efficiently compensates the inter-core XT improving Q-factor by 4.82 dB and (b) achieve a momentous gain in transmission reach, increasing the maximum achievable distance from 480 km to 1208 km, via analytical analysis. Simulation results confirm that inter-core XT distortions are more relentless for cores fabricated around the central axis of cladding. Predominantly, XT induced Q-penalty can be suppressed to be less than 1 dB up-to ‑11.56 dB of inter-core XT over 800 km MCF, offering flexibility to fabricate dense core structures with same cladding diameter. Moreover, this report outlines the relationship between core pitch and forward-error correction (FEC).

  10. Analysis of subpulse generation from delayed-interference signal-wavelength converter for wide carrier recovery rate range

    DEFF Research Database (Denmark)

    Sakaguchi, J.; Nielsen, Mads Lønstrup; Ohira, T.;

    2008-01-01

    The generation of subpulses in delayed-interference signal-wavelength converters (DISCS) had been suspected as a Curse of waveform degradation in their application in ultrafast (similar to 160GHz) optical time division multiplexing (OTDM) communication systems. We reported its first observation i...

  11. High accuracy wavelength locking of a DFB laser using tunable polarization interference filter

    Institute of Scientific and Technical Information of China (English)

    Xiyao Chen(陈曦曜); Jianping Xie(谢建平); Tianpeng Zhao(赵天鹏); Hai Ming(明海); Anting Wang(王安廷); Wencai Huang(黄文财); Liang Lü(吕亮); Lixin Xu(许立新)

    2003-01-01

    A temperature-tunable polarization interference filter (PIF) made of YVO4 crystal has been presented and applied for wavelength locking of a distributed feedback (DFB) semiconductor laser in dense wavelength-division-multiplexing (DWDM) optical communication systems. This new design offers a flexible way to monitor and then lock an operating wavelength of DFB laser to any preselected point without dead spots.The results show that the laser wavelength can be locked with accuracy better than ±0.01 nm with much relaxed requirement on temperature stability of the filter.

  12. Hardware Implementation of a Genetic Algorithm Based Canonical Singed Digit Multiplierless Fast Fourier Transform Processor for Multiband Orthogonal Frequency Division Multiplexing Ultra Wideband Applications

    Directory of Open Access Journals (Sweden)

    Mahmud Benhamid

    2009-01-01

    Full Text Available Problem statement: Ultra Wide Band (UWB technology has attracted many researchers' attention due to its advantages and its great potential for future applications. The physical layer standard of Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM UWB system is defined by ECMA International. In this standard, the data sampling rate from the analog-to-digital converter to the physical layer is up to 528 M sample sec-1. Therefore, it is a challenge to realize the physical layer especially the components with high computational complexity in Very Large Scale Integration (VLSI implementation. Fast Fourier Transform (FFT block which plays an important role in MB-OFDM system is one of these components. Furthermore, the execution time of this module is only 312.5 ns. Therefore, if employing the traditional approach, high power consumption and hardware cost of the processor will be needed to meet the strict specifications of the UWB system. The objective of this study was to design an Application Specific Integrated Circuit (ASIC FFT processor for this system. The specification was defined from the system analysis and literature research. Approach: Based on the algorithm and architecture analysis, a novel Genetic Algorithm (GA based Canonical Signed Digit (CSD Multiplier less 128-point FFT processor and its inverse (IFFT for MB-OFDM UWB systems had been proposed. The proposed pipelined architecture was based on the modified Radix-22 algorithm that had same number of multipliers as that of the conventional Radix-22. However, the multiplication complexity and the ROM memory needed for storing twiddle factors coefficients could be eliminated by replacing the conventional complex multipliers with a newly proposed GA optimized CSD constant multipliers. The design had been coded in Verilog HDL and targeted Xilinx Virtex-II FPGA series. It was fully implemented and tested on real hardware using Virtex-II FG456 prototype board and logic analyzer

  13. Implementation of orthogonal frequency division multiplexing (OFDM) and advanced signal processing for elastic optical networking in accordance with networking and transmission constraints

    Science.gov (United States)

    Johnson, Stanley

    An increasing adoption of digital signal processing (DSP) in optical fiber telecommunication has brought to the fore several interesting DSP enabled modulation formats. One such format is orthogonal frequency division multiplexing (OFDM), which has seen great success in wireless and wired RF applications, and is being actively investigated by several research groups for use in optical fiber telecom. In this dissertation, I present three implementations of OFDM for elastic optical networking and distributed network control. The first is a field programmable gate array (FPGA) based real-time implementation of a version of OFDM conventionally known as intensity modulation and direct detection (IMDD) OFDM. I experimentally demonstrate the ability of this transmission system to dynamically adjust bandwidth and modulation format to meet networking constraints in an automated manner. To the best of my knowledge, this is the first real-time software defined networking (SDN) based control of an OFDM system. In the second OFDM implementation, I experimentally demonstrate a novel OFDM transmission scheme that supports both direct detection and coherent detection receivers simultaneously using the same OFDM transmitter. This interchangeable receiver solution enables a trade-off between bit rate and equipment cost in network deployment and upgrades. I show that the proposed transmission scheme can provide a receiver sensitivity improvement of up to 1.73 dB as compared to IMDD OFDM. I also present two novel polarization analyzer based detection schemes, and study their performance using experiment and simulation. In the third implementation, I present an OFDM pilot-tone based scheme for distributed network control. The first instance of an SDN-based OFDM elastic optical network with pilot-tone assisted distributed control is demonstrated. An improvement in spectral efficiency and a fast reconfiguration time of 30 ms have been achieved in this experiment. Finally, I

  14. Wavelength-domain RF photonic signal processing

    Science.gov (United States)

    Gao, Lu

    This thesis presents a novel approach to RF-photonic signal processing applications based on wavelength-domain optical signal processing techniques using broadband light sources as the information carriers, such as femtosecond lasers and white light sources. The wavelength dimension of the broadband light sources adds an additional degree of freedom to conventional optical signal processing systems. Two novel wavelength-domain optical signal processing systems are presented and demonstrated in this thesis. The first wavelength-domain RF photonic signal processing system is a wavelength-compensated squint-free photonic multiple beam-forming system for wideband RF phased-array antennas. Such a photonic beam-forming system employs a new modulation scheme developed in this thesis, which uses traveling-wave tunable filters to modulate wideband RF signals onto broadband optical light sources in a frequency-mapped manner. The wavelength dimension of the broadband light sources provides an additional dimension in the wavelength-compensated Fourier beam-forming system for mapping the received RF frequencies to the linearly proportional optical frequencies, enabling true-time-delay beam forming, as well as other novel RF-photonic signal processing functions such as tunable filtering and frequency down conversion. A new slow-light mechanism, the SLUGGISH light, has also been discovered with an effective slow-light velocity of 86 m/s and a record time-bandwidth product of 20. Experimental demonstration of true-time-delay beam forming based on the SLUGGISH light effect has also been presented in this thesis. In the second wavelength-domain RF photonic signal processing system, the wavelength dimension increases the information carrying capacity by spectrally multiplexing multiple wavelength channels in a wavelength-division-multiplexing fiber-optic communication system. A novel ultrafast all-optical 3R (Re-amplification, Retiming, Re-shaping) wavelength converter based on

  15. Process/health monitoring for wind turbine blade by using FBG sensors with multiplexing techniques

    Science.gov (United States)

    Eum, S. H.; Kageyama, K.; Murayama, H.; Uzawa, K.; Ohsawa, I.; Kanai, M.; Igawa, H.

    2008-04-01

    In this study, we applied fiber Bragg grating sensors to conduct process/health monitoring of wind turbine blade manufactured by VaRTM. In this study, we used a long gauge FBG (about 100mm) based optical frequency domain reflectometory (OFDR) and 8 FBGs on a single fiber based wavelength division multiplexing (WDM). Resin flow front and resin cure were detected during VaRTM. After manufacturing, structural health monitoring was conducted with the blades. These sensors with multiplexing techniques were able to monitor VaRTM process and wind turbine blade successfully.

  16. 200 GHz-spacing 8-channel multi-wavelength lasers for WDM-PON optical line terminal sources.

    Science.gov (United States)

    Oh, Su Hwan; Shin, Jang-Uk; Kim, Ki Soo; Lee, Dong-Hoon; Park, Sang-Ho; Sung, Hee-Kyung; Baek, Yong-Soon; Oh, Kwang-Ryong

    2009-05-25

    We have fabricated modules of 8-channel multi-wavelength lasers (MWLs) with a wavelength separation of 200 GHz for the wavelength division multiplexed-passive optical network (WDM-PON) optical line terminal sources. The variation in the output power is minimized by inserting silicone between the superluminescent diode (SLD) and the silica waveguide. The wavelength shift of each channel is less than 0.21 nm from the ITU grid and can be controlled in the range of 0.36 nm without any reductions of the output power by a tuning heater. MWLs operated successfully in the direct modulation for 1.25 Gbit/s transmissions over 20 km.

  17. Eight-wavelength distributed-Bragg-reflector (DBR) laser array transmitter for WDM applications

    Science.gov (United States)

    Fallahi, Mahmoud; McGreer, K. A.; Delage, Andre; Neophytou, A.; Templeton, Ian M.; Champion, Garth; Chatenoud, F.; Barber, Richard A.; Wang, Weijian; He, Jian Jun; Koteles, Emil S.

    1995-03-01

    We report on the design, growth, fabrication and characterization of monolithic wavelength division multiplexed (WDM) laser array transmitter and receiver chips produced by the Canadian Solid State Optoelectronics Consortium. The transmitter chip includes multiple, discrete wavelength, distributed Bragg reflector (DBR) laser diodes monolithically integrated with waveguide combiners fabricated using an InGaAs/GaAs heterostructure. The corresponding wavelength demultiplexer unit is based on a Rowland circle grating spectrometer monolithically integrated with a metal-semiconductor-metal (MSM) detector array fabricated on an InGaAs/AlGaAs/GaAs heterostructure. The epitaxial layer wafers for both transmitter and receiver modules were grown in single molecular beam epitaxy (MBE) runs.

  18. Advanced Silicon Photonic Transceivers - the Case of a Wavelength Division and Polarization Multiplexed Quadrature Phase Shift Keying Receiver for Terabit/s Optical Transmission

    Science.gov (United States)

    2017-03-10

    Component Analyzer ( LCA ) and is shown in Fig. 3. The transimpedance (RF) of the TIA was swept over the range of possible values, i.e. R! = 400 Ω/N with N...Optical signal to noise ratio VOA variable optical attenuator ASE amplified spontaneous emission LO local oscillator TX transmitter LCA lightwave

  19. Indoor RF signal distribution using a coherence multiplexed/subcarrier multiplexed optical transmission system

    NARCIS (Netherlands)

    Taniman, Robert; Meijerink, Arjan; Etten, van Wim; Haartsen, Jaap

    2003-01-01

    A Radio over Fiber (RoF) distribution network based on single-mode fiber (SMF) and a combination of coherence multiplexing (CM) and subcarrier multiplexing (SCM) is proposed. CM is a relatively unknown and potentially inexpensive form of photonic code-division multiplexing, and is used here as a mea

  20. No guard-band wavelength translation of Nyquist OTDM-WDM signal for spectral defragmentation in an elastic add-drop node.

    Science.gov (United States)

    Tan, Hung Nguyen; Tanizawa, Ken; Inoue, Takashi; Kurosu, Takayuki; Namiki, Shu

    2013-09-01

    We demonstrate a seamless spectral defragmentation in an elastic all-optical add-drop node based on wavelength division multiplexing (WDM) channels of Nyquist optical time division multiplexing (OTDM) signal. A 172 Gbaud Nyquist OTDM signal occupying a 215 GHz range is elastically shifted adjacent to its neighboring channel, completely filling a variable spectral gap caused by the dropped channel. The frequency shift is done in a dual-stage polarization-diversity four wave mixing-based converter using polarization-maintaining highly nonlinear fiber. The spectrally defragmented signals are successfully transmitted over a 80 km fiber link with BER<10(-9).

  1. Demonstration of 5.1 Tbit/s data capacity on a single-wavelength channel

    OpenAIRE

    Mulvad, Hans Christian Hansen; Galili, Michael; Oxenløwe, Leif Katsuo; Hu, Hao; Clausen, Anders; Jensen, Jesper Bevensee; Peucheret, Christophe; Jeppesen, Palle

    2010-01-01

    We have generated a single-wavelength data signal with a data capacity of 5.1 Tbit/s. The enabling techniques to generate the data signal are optical time-division multiplexing up to a symbol rate of 1.28 Tbaud, differential quadrature phase shift keying as data format, and polarisation-multiplexing. For the first time, error-free performance with a bit error rate less than 1e-9 is demonstrated for the 5.1 Tbit/s data signal. This is achieved in a back-to-back configuration using a direct det...

  2. An 8-channel wavelength demultiplexer based on photonic crystal fiber

    Science.gov (United States)

    Malka, Dror

    2017-05-01

    We propose a novel 8-channel wavelength demultiplexer based on photonic crystal fiber (PCF) structures that operate at 1530nm, 1535nm, 1540nm, 1545nm, 1550nm, 1555nm, 1560nm and 1565nm wavelengths. The new design is based on replacing some air-holes zones with silicon nitride and lithium niobate materials along the PCF axis with optimization of the PCF size. The reason of using these materials is because that each wavelength has a different value of coupling length. Numerical investigations were carried out on the geometrical parameters by using a beam propagation method (BPM). Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530- 1565nm) with low crosstalk ((-16.88)-(-15.93) dB) and bandwidth (4.02-4.69nm). Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM) technology.

  3. Characterization of Wavelength Tunable Lasers for Future Optical Communication Systems

    Directory of Open Access Journals (Sweden)

    Prince M. Anandarajah

    2010-02-01

    Full Text Available The use of tunable lasers (TL in dense wavelength division multiplexed (DWDM networks for optical switching, routing and networking has gained a lot of interest in recent years. Employment of such TLs as tunable transmitters in wavelength packet switched (WPS networks is one of the possible applications of these devices. In such systems, the information to be transmitted could be encoded onto a destination dependent wavelength and the routing of traffic could be performed on a packet-by-packet basis. The authors investigate the possibility of using TLs in DWDM WPS networks by focusing on the characterisation of the instantaneous frequency drift of a TL due to wavelength tuning and direct modulation. Characterization of the linewidth of the TLs is also presented to verify the feasibility of using TLs in systems employing advanced modulation formats.

  4. Design of dual ring wavelength filters for WDM applications

    Science.gov (United States)

    Sathyadevaki, R.; Shanmuga sundar, D.; Sivanantha Raja, A.

    2016-12-01

    Wavelength division multiplexing plays a prime role in an optical communication due to its advantages such as easy network expansion, longer span lengths etc. In this work, photonic crystal based filters with the dual rings are proposed which act as band pass filters (BPF) and channel drop filter (CDF) that has found a massive applications in C and L-bands used for wavelength selection and noise filtering at erbium doped fiber amplifiers and dense wavelength division multiplexing operation. These filters are formulated on the square lattice with crystal rods of silicon material of refractive index 3.4 which are perforated on an air of refractive index 1. Dual ring double filters (band pass filter and channel drop filter) on single layout possess passing and dropping band of wavelengths in two distinct arrangements with entire band quality factors of 92.09523 & 505.263 and 124.85019 & 456.8633 for the pass and drop filters of initial setup and amended setup respectively. These filters have the high-quality factor with broad and narrow bandwidths of 16.8 nm & 3.04 nm and 12.85 nm & 3.3927 nm. Transmission spectra and band gap of the desired filters is analyzed using Optiwave software suite. Two dual ring filters incorporated on a single layout comprises the size of 15×11 μm which can also be used in the integrated photonic chips for the ultra-compact unification of devices.

  5. Dependence of the bit error rate on the signal power and length of a single-channel coherent single-span communication line (100 Gbit s-1) with polarisation division multiplexing

    Science.gov (United States)

    Gurkin, N. V.; Konyshev, V. A.; Nanii, O. E.; Novikov, A. G.; Treshchikov, V. N.; Ubaydullaev, R. R.

    2015-01-01

    We have studied experimentally and using numerical simulations and a phenomenological analytical model the dependences of the bit error rate (BER) on the signal power and length of a coherent single-span communication line with transponders employing polarisation division multiplexing and four-level phase modulation (100 Gbit s-1 DP-QPSK format). In comparing the data of the experiment, numerical simulations and theoretical analysis, we have found two optimal powers: the power at which the BER is minimal and the power at which the fade margin in the line is maximal. We have derived and analysed the dependences of the BER on the optical signal power at the fibre line input and the dependence of the admissible input signal power range for implementation of the communication lines with a length from 30 - 50 km up to a maximum length of 250 km.

  6. A New 1×K Tunable Multi-wavelength Router and its Features

    Institute of Scientific and Technical Information of China (English)

    GAN Chaoqin; SUN Xiaohan; ZHANG Mingde

    2002-01-01

    Tunable wavelength routers (TWRs) for multiple wavelength selection are key devices in dynamic wavelength-routing wavelength division multiplexing (WDM) networks. In this paper, by cascading conventional 2×2 TWRs, a new 1×K TWR is proposed for large-scale dynamic wavelength-routing WDM networks. When the cascading numbers are smaller, the 1×K TWR can be directly applied to networking WDM networks. When the cascading numbers are larger, the 1×K TWR can be carried out by the integrating method and be extensively used to networking various multi-wavelength optical networks by the way of “EDFA+TWR”. Though the cascading method proposed is based on the acousto-optic TWRs, it can be also applied to cascading other kinds of TWRs.

  7. A Novel Solution to the Dynamic Routing and Wavelength Assignment Problem in Transparent Optical Networks

    CERN Document Server

    Bhanja, Urmila; Roy, Rajarshi; 10.5121/ijcnc.2010.2209

    2010-01-01

    We present an evolutionary programming algorithm for solving the dynamic routing and wavelength assignment (DRWA) problem in optical wavelength-division multiplexing (WDM) networks under wavelength continuity constraint. We assume an ideal physical channel and therefore neglect the blocking of connection requests due to the physical impairments. The problem formulation includes suitable constraints that enable the algorithm to balance the load among the individuals and thus results in a lower blocking probability and lower mean execution time than the existing bio-inspired algorithms available in the literature for the DRWA problems. Three types of wavelength assignment techniques, such as First fit, Random, and Round Robin wavelength assignment techniques have been investigated here. The ability to guarantee both low blocking probability without any wavelength converters and small delay makes the improved algorithm very attractive for current optical switching networks.

  8. Tunable all-optical wavelength broadcasting in a PPLN with multiple QPM peaks.

    Science.gov (United States)

    Ahlawat, Meenu; Tehranchi, Amirhossein; Pandiyan, Krishnamoorthy; Cha, Myoungsik; Kashyap, Raman

    2012-11-19

    We experimentally demonstrate tunable multiple-idler wavelength broadcasting of a signal to selective channels for wavelength division multiplexing (WDM). This is based on cascaded χ(2) nonlinear mixing process in a novel multiple-QPM 10-mm-long periodically poled LiNbO3 having an aperiodic domain in the center. The idlers' spacing is varied utilizing detuning of the pump wavelength within the SHG bandwidth. The temperature-assisted tuning of QPM pump wavelengths allows shifting the idlers together to different set of WDM channels. Our experimental results indicate that an overall idler wavelength shift of less than 10 nm realized by selecting pump wavelengths via temperature tuning, is sufficient to cover up to 40 WDM channels for multiple idlers broadcasting.

  9. Efficient Generation of Frequency-Multiplexed Entangled Single Photons

    Science.gov (United States)

    Qiu, Tian-Hui; Xie, Min

    2016-12-01

    We present two schemes to generate frequency-multiplexed entangled (FME) single photons by coherently mapping photonic entanglement into and out of a quantum memory based on Raman interactions. By splitting a single photon and performing subsequent state transfer, we separate the generation of entanglement and its frequency conversion, and find that the both progresses have the characteristic of inherent determinacy. Our theory can reproduce the prominent features of observed results including pulse shapes and the condition for deterministically generating the FME single photons. The schemes are suitable for the entangled photon pairs with a wider frequency range, and could be immune to the photon loss originating from cavity-mode damping, spontaneous emission, and the dephasing due to atomic thermal motion. The sources might have significant applications in wavelength-division-multiplexing quantum key distribution.

  10. Multiplexed entangled photon sources for all fiber quantum networks

    CERN Document Server

    Zhou, Yin-Hai Li Zhi-Yuan; Xu, Li-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such quantum network can be realized by all fiber elements, which takes advantage of low transmission loss,low cost, scalable and mutual fiber communication techniques such as dense wavelength division multiplexing. Therefore high quality entangled photon sources based on fibers are on demanding for building up such kind of quantum network. Here we report multiplexed polarization and timebin entanglement photon sources based on dispersion shifted fiber operating at room temperature. High qualities of entanglement are characterized by using interference, Bell inequality and quantum state tomography. Simultaneous presence of entanglements in multichannel pairs of a 100GHz DWDM shows the great capacity for entanglements distribution over multi-users. Our research provides a versatile platform and moves a first step toward constructing an all f...

  11. 基于伪逆的多小区FDD系统中的联合空分复用方法%Joint spatial division and multiplexing based on the pseudo-inverse method in multi-cells FDD system

    Institute of Scientific and Technical Information of China (English)

    谢显中; 葛振涛; 雷维嘉

    2015-01-01

    云无线接入网(cloud radio access network,C-RAN)架构实现了小区间的联合处理,大规模多输入多输出(massive multiple-input multiple-output,Massive MIMO)技术在系统容量和频谱效率方面具有巨大的优势,但由于训练和反馈开销较大使得Massive MIMO难以应用于频分双工(frequency division duplex,FDD)系统.C-RAN架构下,考虑在不同小区之间引入联合空分复用(joint spatial division and multiplexing,JSDM)技术减少导频序列检测和信道信息反馈开销,在高酉条件不满足时,采用基于伪逆的方法来减少组间干扰,通过迫零(zero-forcing,ZF)滤波实现组内用户间干扰消除.理论分析和仿真结果表明,设计的一阶预编码矩阵相对于块对角化(block diagonalization, BD)算法复杂度得到降低,其和速率有一定改进.

  12. 基于离散傅立叶变换的重叠频分复用通信系统%A novel DFT based overlapped frequency division multiplexing(OvFDM)system

    Institute of Scientific and Technical Information of China (English)

    王键; 杨讯; 张曦林; 李道本

    2008-01-01

    提出了新的基于离散傅立叶变换(DFT)的重叠频分复用(Overlapped Fre-quency Division Muhiplexing-OvFDM)或非正交频分复用(Non-orthogonal Fre-quency Division Multiplexing-NOFDM)系统.该系统利用相互重叠的子载波对所发送的数据符号序列进行调制,形成复调制信号,接收端采用最大似然序列检测.该系统的频谱效率与重叠重数成正比,可以大幅度的提高频谱效率;并且该系统子载波带宽大于信道相关带宽,系统在随机时变信道中会自动产生隐分集增益,因此具有较强的抗衰落能力.

  13. A double wavelength DFB laser with an identical active area for CWDM

    Institute of Scientific and Technical Information of China (English)

    Hongyun Xie; Wei Wang; Fan Zhou; Jing Bian; Baojun Wang; Lufeng Wang

    2005-01-01

    A novel distribute feedback (DFB) laser which gave two different wavelengths under two distinct work conditions was fabricated. The laser consists of two Bragg gratings with different periods corresponding to wavelength spacing of 20 nm in an identical active area. When driving current was injected into one of the different sections separately, two different wavelengths at 1542.4 and 1562.5 nm were realized. The side mode suppression ratio (SMSR) of 45 dB or more both for the two Bragg wavelengths were achieved. The fabricating process of the laser was just the same as that of traditional DFB laser diode. This device can be potentially used in coarse wavelength division multiplexer (CWDM) as a promising light source and the technology idea can be used to enlarge the transmission capacity in metro area network (MAN).

  14. 级联 RS 码的自由空间光通信正交频分复用系统性能分析%Performance of the Free Space Othogonal-Frequency Division Multiplexing System Concatenated RS Codes

    Institute of Scientific and Technical Information of China (English)

    赵黎; 佘彬华

    2013-01-01

    为了有效抵御大气散射效应和提高频谱利用率,提出了自由空间光通信正交频分复用系统。由于大气信道的不稳定性,该系统在传输过程中导致误码率很高。将里德-所罗门码引入自由空间光通信正交频分复用系统中,对其进行了半实物仿真,仿真结果表明:当误码率为10-2时,正交频分复用较开关键控性能优越4 dB ;在广延雨、平流雾、沙尘天等不同的天气条件下,当误码率为10-5时,里德-所罗门(255,223)信道编码较未编码性能优越4~5 dB 。正交频分复用系统和里德-所罗门码的技术能降低系统的误码率。%For the purpose of effective resisting of the atmospheric scattering and impoving of the spectrum utilization rate .Free space orthogonal frequency division multiplexing (FSO-OFDM ) system is proposed .Due to the instability of the atmospheric channel ,the system ,which is still in the process of transmission ,will be affected by various factors ,resulting in a high error rate .Reed-Solomon(RS) code is applied to the FSO-OFDM system .At last ,the semi-physical simulation has been conducted .The simulation results show that when the BER is 10-2 ,the performance of orthogonal frequency division multiplexing (OFDM ) is superior to 4 dB compared with OOK .In different weather conditions (extensa rain ,advection fog ,dust days) ,when the BER is 10-5 ,the performance of RS(225 ,223) channel coding is superior to 4 ~ 5 dB compared with uncoding .The results show that ,OFDM system and RS code technology can reduce the system BER .

  15. Proposal for a 1 × 3 Goos-Hänchen shift-assisted de/multiplexer based on a multilayer structure containing quantum dots

    Science.gov (United States)

    Sattari, H.; Ebadollahi-Bakhtevar, S.; Sahrai, M.

    2016-10-01

    A multilayer structure with the wavelength selective features based on Goos-Hänchen (GH) shift is proposed and investigated. We present a layered media containing quantum dots for active control of the GH shift for the reflected light. This configuration includes a distributed Bragg reflector to have minimum optical power transmission to the substrate. In addition, a passive cladding layer is used to enhance the total lateral shift for the reflected beams. For a fixed structure and incident angle, our results demonstrate that by proper manipulation of the optical properties and susceptibility of the active layer, de/multiplexing capabilities of such a device could be controlled. This type of grating-less device can be used as a compact wavelength division multiplexing system with actively controllable channel spacing. We demonstrate possibility of a 1 × 3 de/multiplexer with channel spacing of 2 nm .

  16. Ultra-large number of transmission channels in space division multiplexing using few-mode multi-core fiber with optimized air-hole-assisted double-cladding structure.

    Science.gov (United States)

    Watanabe, Tatsuhiko; Kokubun, Yasuo

    2014-04-07

    The ultimate number of transmission channels in a fiber for the space division multiplexing (SDM) is shown by designing an air-hole-assisted double-cladding few-mode multi-core fiber. The propagation characteristics such as the dispersion and the mode field diameter are almost equalized for all cores owing to the double cladding structure, and the crosstalk between adjacent cores is extremely suppressed by the heterogeneous arrangement of cores and the air holes surrounding the cores. Optimizing the structure of the air-hole-assisted double-cladding, ultra dense core arrangements, e.g. 129 cores in a core accommodated area with 200 μm diameter, can be realized with low crosstalk of less than -34.3 dB at 100km transmission. In this design, each core supports 3 modes i.e. LP(01), LP(11a), and LP(11b) as the transmission channels, so that the number of transmission channels can be 3-hold greater than the number of cores. Therefore, 387 transmission channels can be realized.

  17. Channel-reuse bidirectional transmission at 10 Gb/s/λ in long-reach DWDM-PON employing self wavelength managed tunable laser

    Science.gov (United States)

    Zhang, Zhiguo; Wang, Jiahe; Jiang, Xu; Chen, Xue; Wang, Liqian

    2015-05-01

    We experimentally demonstrate a channel-reuse, bidirectional, 10 Gb/s/λ, long-reach dense wavelength-division-multiplexing passive optical network (DWDM-PON) and an optical beat noise-based automatic wavelength control method for a tunable laser used in a colorless optical network unit (ONU). A 42 km reach, channel-reuse, full-duplex, 10 Gb/s transmission on a 50 GHz DWDM grid is achieved. Transmission performance is also measured with different optical-signal-to-Rayleigh-backscattering-noise ratios (OSRBNRs) and different central wavelength shifts (WSs) between upstream signal and downstream signal in the channel-reuse system.

  18. Multiplexed entangled photon-pair sources for all-fiber quantum networks

    Science.gov (United States)

    Zhou, Zhi-Yuan; Li, Yin-Hai; Xu, Li-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-11-01

    The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such a quantum network can be realized using only fiber elements, thus deriving the advantages of low transmission loss, low cost, scalability, and integrability through mature fiber communication techniques such as dense wavelength division multiplexing. Hence high-quality entangled-photon sources based on fibers are in high demand. Here we report multiplexed polarization- and time-bin-entangled photon-pair sources based on the dispersion-shifted fiber operating at room temperature. The associated high quality of entanglement is characterized using interference, Bell's inequality, and quantum state tomography. The simultaneous presence of both types of entanglement in multi-channel pairs of a 100-GHz dense wavelength division multiplexing device indicates a great capacity in distributing entangled photons over multiple users. Our design provides a versatile platform and takes a big step toward constructing an all-fiber quantum network.

  19. Multiplexed entangled photon-pair sources for all-fiber quantum networks

    Science.gov (United States)

    Li, Yin-Hai; Zhou, Zhi-Yuan; Xu, Zhao-Huai; Xu, Li-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-10-01

    The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such a quantum network can be realized using only fiber elements, thus deriving the advantages of low transmission loss, low cost, scalability, and integrability through mature fiber communication techniques such as dense wavelength division multiplexing. Hence high-quality entangled-photon sources based on fibers are in high demand. Here we report multiplexed polarization- and time-bin-entangled photon-pair sources based on the dispersion-shifted fiber operating at room temperature. The associated high quality of entanglement is characterized using interference, Bell's inequality, and quantum state tomography. The simultaneous presence of both types of entanglement in multichannel pairs of a 100-GHz dense wavelength division multiplexing device indicates a great capacity in distributing entangled photons over multiple users. Our design provides a versatile platform and takes a big step toward constructing an all-fiber quantum network.

  20. Symmetric 10 Gb/s wavelength reused bidirectional RSOA based WDM-PON with DPSK modulated downstream and OFDM modulated upstream signals

    Science.gov (United States)

    Choudhury, Pallab K.; Khan, Tanvir Zaman

    2016-08-01

    A 10 Gb/s bidirectional wavelength division multiplexing passive optical network (WDM-PON) with reflective semiconductor optical amplifier (RSOA) based colorless optical network unit (ONU) is proposed and analyzed for next generation gigabit class optical access network. Differential phase shift keying (DPSK) modulated signal is used in downstream and further reused as a seeding wavelength for upstream data modulation. By exploiting the constant envelope property of DPSK seed signal, the re-modulation noise in upstream receiver is effectively minimized without employing any constraint on extinction ratio of downstream signal. Orthogonal frequency division multiplexing (OFDM) signal is used in upstream transmission to overcome the limited bandwidth (∼1 GHz) response of RSOA remodulation. The results show that the proposed 10 Gb/s symmetric WDM-PON can achieve good performance over 25 km fiber transmission with error free operation in downstream and bit error rate (BER) lower than forward error correction (FEC) limit in upstream.

  1. Mapping chemical concentration in binary thin organic films via multi-wavelength scanning absorption microscopy (MWSAM)

    Science.gov (United States)

    Berriman, Garth; Routley, Ben; Holdsworth, John; Zhou, Xiaojing; Belcher, Warwick; Dastoor, Paul

    2014-09-01

    The composition and thickness of binary thin organic films is determined by measuring the optical absorption at multiple wavelengths across the film surface and performing a component analysis fit to absorption standards for the materials. The multiple laser wavelengths are focused onto the surface using microscope objectives and raster scanned across the film surface using a piezo-electric actuator X-Y stage. All of the wavelengths are scanned simultaneously with a frequency division multiplexing system used to separate the individual wavelength response. The composition values are in good quantitative agreement with measurements obtained by scanning transmission x-ray microscopy (STXM). This new characterization technique extends quantitative compositional mapping of thin films to thickness regimes beyond that accessible by STXM.

  2. Improved digital backward propagation for the compensation of inter-channel nonlinear effects in polarization-multiplexed WDM systems.

    Science.gov (United States)

    Mateo, Eduardo F; Zhou, Xiang; Li, Guifang

    2011-01-17

    An improved split-step method (SSM) for digital backward propagation (DBP) applicable to wavelength-division multiplexed (WDM) transmission with polarization-division multiplexing (PDM) is presented. A coupled system of nonlinear partial differential equations, derived from the Manakov equations, is used for DBP. The above system enables the implementation of DBP on a channel-by-channel basis, where only the effect of phase-mismatched four-wave mixing (FWM) is neglected. A novel formulation of the SSM for PDM-WDM systems is presented where new terms are included in the nonlinear step to account for inter-polarization mixing effects. In addition, the effect of inter-channel walk-off is included. This substantially reduces the computational load compared to the conventional SSM.

  3. Integrated all-optical wavelength multicasting for 40 Gbit/s PDM-QPSK signals using a single silicon waveguide

    Science.gov (United States)

    Feng, Xianglian; Wu, Zhihang; Wang, Xiaoyan; Gao, Shiming

    2017-09-01

    All-optical wavelength multicasting is presented and experimentally demonstrated for 40 Gbit/s polarization-division-multiplexed (PDM) nonreturn-to-zero quadrature phase-shift keying (QPSK) signals using four-wave mixing (FWM) with angled-polarization pumps in a silicon waveguide. Five multicast channels are obtained on the generated idlers. The eye diagrams, constellation diagrams, and bit error rates (BERs) of the QPSK sequences on the two polarization states are measured for each wavelength channel. The power penalties of all these multicast QPSK sequences on x or y polarization state are less than 2.0 dB at the BER of 3 × 10-3.

  4. Determination of Transmission Routing of OXC Nodes Based on AWG Multiplexer by Matrix Transformation

    Institute of Scientific and Technical Information of China (English)

    GUO Ai-huang; FU Jun-mei

    2004-01-01

    The structures of the space switching and the wavelength switching optical cross connect (OXC)nodes which are based on the arrayed waveguide grating (AWG) multiplexer are analyzed. By the matrix transformation relation between the input and output wavelengths of the AWG multiplexer, the wavelength transmission routings of the space switching and wavelength switching OXC nodes are determined.

  5. Performance analysis of low-complexity adaptive frequency-domain equalization and MIMO signal processing for compensation of differential mode group delay in mode-division multiplexing communication systems using few-mode fibers

    Science.gov (United States)

    Weng, Yi; He, Xuan; Pan, Zhongqi

    2016-02-01

    Mode-division multiplexing (MDM) transmission systems utilizing few-mode fibers (FMF) have been intensively explored to sustain continuous traffic growth. The key challenges of MDM systems are inter-modal crosstalk due to random mode coupling (RMC), and largely-accumulated differential mode group delay (DMGD), whilst hinders mode-demultiplexer implementation. The adaptive multi-input multi-output (MIMO) frequency-domain equalization (FDE) can dynamically compensate DMGD using digital signal processing (DSP) algorithms. The frequency-domain least-mean squares (FD-LMS) algorithm has been universally adopted for high-speed MDM communications, mainly for its relatively low computational complexity. However, longer training sequence is appended for FD-LMS to achieve faster convergence, which incurs prohibitively higher system overhead and reduces overall throughput. In this paper, we propose a fast-convergent single-stage adaptive frequency-domain recursive least-squares (FD-RLS) algorithm with reduced complexity for DMGD compensation at MDM coherent receivers. The performance and complexity comparison of FD-RLS, with signal-PSD-dependent FD-LMS method and conventional FD-LMS approach, are performed in a 3000 km six-mode transmission system with 65 ps/km DMGD. We explore the convergence speed of three adaptive algorithms, including the normalized mean-square-error (NMSE) per fast Fourier transform (FFT) block at 14-30 dB OSNR. The fast convergence of FD-RLS is exploited at the expense of slightly-increased necessary tap numbers for MIMO equalizers, and it can partially save the overhead of training sequence. Furthermore, we demonstrate adaptive FD-RLS can also be used for chromatic dispersion (CD) compensation without increasing the filter tap length, thus prominently reducing the DSP implementation complexity for MDM systems.

  6. Sub-picometer multi-wavelength detector based on highly sensitive nanomechanical resonator

    Science.gov (United States)

    Maeda, Etsuo; Kometani, Reo

    2017-07-01

    The wavelength division multiplexing (WDM) method for near infrared (NIR) optical fiber (1530-1565 nm) is the system that is wildly used for intercontinental communication. WDM achieves high-speed and large-capacity communication, but costs a lot because the high-resolution (˜10 pm) wavelength locker for wavelength stabilization only corresponds to a single wavelength. In this report, we propose a highly sensitive sub-picometer multi-wavelength detector that substitutes a typical single-wavelength detector for WDM. Our wavelength detector consists of a narrow band (FWHM 20 000) nanomechanical resonator. The photonic absorber confines and transforms the illuminated NIR light wave into thermal stress, and then, the thermal stress in the nanomechanical resonator will appear as the eigenfrequency shift of the nanomechanical resonator. Through experimental works with an NIR laser and optical Doppler vibration meter, the sensitivity of our wavelength detector was determined to be 0.196 pm in the 10-nm-range of the NIR region. Our sub-picometer multi-wavelength detector will achieve a fast, wide-band, and cost-effective optical communication system.

  7. Multi-wavelength fiber ring laser based on semiconductor optical amplifier and sampled fiber Bragg grating in a Sagnac loop interferometer%基于半导体光放大器和取样光纤光栅结合Sagnac环的多波长光纤激光器

    Institute of Scientific and Technical Information of China (English)

    冯素春; 许鸥; 鲁韶华; 宁提纲; 简水生

    2009-01-01

    Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.

  8. A Novel Approach for Improving Communication by Wavelength Utilization

    Directory of Open Access Journals (Sweden)

    Shrangesh Dahat

    2012-06-01

    Full Text Available Optical networks using wavelength division multiplexing (WDM technology modulate multiple channels over a single fiber. The most common architecture utilized for establishing communication in WDM optical networks is wavelength routing, where the communication between a source and a destination node is performed by setting up optical channels between them, called light-paths from the network perspective. In optical WDM networks, transmission of information along optical lines is advantageous since it has high transmission capacity, scalability, feasibility and also high reliability. But since large amount of information is being carried, any problem during transmission can lead to severe damage to the data being carried. In this paper, we propose to develop a routing and wavelength utilization algorithm which considers two constraints for selecting the best path. The two constraints are based on the available free load and the number of wavelength used in the link. Based on these constraints, two cost functions on load and wavelength are determined, which yields a combined cost function. For each pair of source and destination, the path with the minimum combined cost function is selected as the primary path for data transmission, allocating the sufficient wavelength. This study paper proposes a RWU algorithm for the problem of establishing the set of efficient light paths for a given set of connection requests. The effectiveness of the proposed RWU algorithm is demonstrated by simulation. This study divides the routing and wavelength allocation process in two step problem with a goal of minimizing Number of wavelength channel and number of wavelength conversion required. This algorithm thus provides a reliable path for the data transmission.

  9. Fabrication and comprehensive modeling of ion-exchanged Bragg optical add-drop multiplexers.

    Science.gov (United States)

    Castro, Jose M; Geraghty, David F; West, Brian R; Honkanen, Seppo

    2004-11-20

    Optical add-drop multiplexers (OADMs) based on asymmetric Y branches and tilted gratings offer excellent-performance in wavelength-division multiplexed systems. To simplify waveguide fabrication, ion-exchange techniques appear to be an important option in photosensitive glasses. Optimum OADM performance depends on how accurately the waveguide fabrication process and tilted Bragg grating operation are understood and modeled. Results from fabrication and comprehensive modeling are compared for ion-exchange processes that use different angles of the tilted grating. The transmission and reflection spectra for the fabricated and simulated OADMs show excellent agreement. The OADM's performance is evaluated in terms of the measured characteristics of the Y branches and tilted gratings.

  10. Cascaded multiplexed optical link on a telecommunication network for frequency dissemination.

    Science.gov (United States)

    Lopez, Olivier; Haboucha, Adil; Kéfélian, Fabien; Jiang, Haifeng; Chanteau, Bruno; Roncin, Vincent; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Giorgio

    2010-08-01

    We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3 x 10(-15) at one second measurement time and 5 x 10(-20) at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

  11. Cascaded multiplexed optical link on a telecommunication network for frequency dissemination

    CERN Document Server

    Lopez, Olivier; Kéfélian, Fabien; Jiang, Haifeng; Chanteau, Bruno; Roncin, Vincent; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Georgio

    2010-01-01

    We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3 \\times 10-15 at one second measurement time and 5 \\times 10-20 at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

  12. Combining spatial domain multiplexing and orbital angular momentum of photon-based multiplexing to increase the bandwidth of optical fiber communication systems

    Science.gov (United States)

    Murshid, Syed; Alanzi, Saud; Hridoy, Arnob; Lovell, Gregory L.; Parhar, Gurinder; Chakravarty, Abhijit; Chowdhury, Bilas

    2016-06-01

    Spatial domain multiplexing/space division multiplexing (SDM) can increase the bandwidth of existing and futuristic optical fibers by an order of magnitude or more. In the SDM technique, we launch multiple single-mode pigtail laser sources of the same wavelength into a carrier multimode fiber at different angles. The launching angles decide the output of the carrier fiber by allocating separate spatial locations for each channel. Each channel follows a helical trajectory while traversing the length of the carrier fiber, thereby allowing spatial reuse of optical frequencies. We launch light from five different single-mode pigtail laser sources (of same wavelength) at different angles (with respect to the axis of the carrier fiber) into the carrier fiber. Owing to helical propagation, five distinct concentric donut-shaped rings with negligible crosstalk at the output end of the fiber were obtained. These SDM channels also exhibit orbital angular momentum (OAM), thereby adding an extradegree of photon freedom. We present the experimental data of five spatially multiplexed channels and compare them with simulated results to show that this technique can potentially improve the data capacity of optical fibers by an order of magnitude: A factor of five using SDM and another factor of two using OAM.

  13. Increasing input power dynamic range of SOA by shifting the transparent wavelength of tunable optical filter

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2001-01-01

    Gain-saturation-induced self-phase modulation (SPM) leading to pulse distortion in a semiconductor optical amplifier (SOA) is overcome by shifting a tunable optical filter (TOF). A recovered or broadened pulse can be obtained after filtering the amplified pulse in the SOA even if the short pulse...... to a longer wavelength for RZ signals and to a shorter for NRZ signals. 80-Gb/s optical time division multiplexing (OTDM) signal amplification in the SOA is demonstrated for the first time. We also demonstrate that a large IPDR for the 80-Gb/s OTDM signal can be obtained by shifting the TOF....

  14. W频段卫星通信中正交频分复用技术的误码性能分析%Bit error rate analysis of orthogonal frequency division multiplexing technology in W-band satellite communication

    Institute of Scientific and Technical Information of China (English)

    赵乐; 宋爱民; 刘剑; 薛斌; 郭兴阳

    2015-01-01

    针对传统的卫星通信频段( C频段、Ku频段、Ka频段)应用逐渐趋于饱和的问题,研究了更高的W频段卫星通信。该频段带宽更宽,可以支持更高的数据传输速率,同等条件下天线尺寸更小并可获得更大的天线增益。正交频分复用技术具有很高的频带利用率,适合于高速数据传输,在W频段具有很好的应用前景。参照“IKNOW”项目中的链路预算,采用固态功放的Rapp模型,对OFDM技术应用在W频段卫星通信中的误码性能进行了仿真分析。仿真结果表明:在考虑功放非线性时,存在一个最佳的输入功率补偿点,使OFDM系统的误码率最低,并且发射功率越高,最佳补偿点对应的误码率越低。%Since traditional band applications ( C-band, Ku-band, Ka-band) for satellite communication will gradually tend to be saturated, the higher W-band was studied. W-band has a wider bandwidth, supports a higher data rate, acquires a smaller equipment size and a bigger antenna gain under the same conditions. Orthogonal Frequency Division Multiplexing ( OFDM) technology has a high spectrum efficiency, which makes it be suitable for high data rate transmission, so it has a good application prospect in W-band. Referring to the link budget of “IKNOW” project and using the Rapp model of solid-state power amplifier, the Bit Error Rate ( BER) of OFDM in W-band was simulated and analyzed. The simulation results show that there is a best input power backoff point which makes the BER be lowest when the nonlinear power amplifier is taken in account, and the higher the transmission power is, the lower the BER of the best input power backoff point will be.

  15. 正交频分复用技术及其在4G移动通信中的应用%Orthogonal Frequency Division Multiplexing Technology and Its Application in 4 G Mobile Communication

    Institute of Scientific and Technical Information of China (English)

    刘巧平; 李艳萍

    2014-01-01

    正交频分复用( OFDM)技术是一种特殊的多载波数字调制技术。由于OFDM的各个子载波存在正交性,极大地利用了频谱资源,所以在一定程度上缓解了未来频谱资源紧缺的问题;OFDM有良好的抗码间干扰能力和对抗频率选择性衰落,能够适应未来无线通信无失真高速数据传播的要求;各个子信道的调制和解调能用FFT和IFFT实现,因而能够满足无线通信系统中的业务要求。文中首先介绍了OFDM技术的基本原理,接着阐述了它的优势以及需要克服的缺陷,再分析了4G移动通信技术的特点,最后讨论了OFDM技术在4G移动通信系统中的应用。%OFDM (Orthogonal Frequency Division Multiplexing) is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier orthogonality exists,great using of spectrum resources,to a certain extent,ease the problem of shortage of spectrum re-sources in the future. OFDM has a good ability to resist intersymbol interference and fight against frequency selective fading,able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement,and thus can satisfy the requirements for the business in the wireless communication system. In this paper,introduce the key techniques of OFDM,describe the advantages of OFDM and the need to overcome the defects,and then analyze the characteristics of 4G mobile communication technology,finally discuss the application of OFDM in 4G mobile communication system.

  16. 一种光正交频分复用系统的联合相位均衡方法%Joint Phase Equalization in Optical Orthogonal Frequency Division Multiplexing System

    Institute of Scientific and Technical Information of China (English)

    高丽娜; 刘剑飞; 曾祥烨; 姜伟虎

    2012-01-01

    The combination of orthogonal frequency division multiplexing (OFDM) technology, coherent receiver and digital singal processing (DSP) is one of the ideal models in long-haul communication. However, optical OFDM receiver is sensitive to phase noise, so it is necessary to compensate phase noise for optical OFDM systems. A joint phase equalization solution to optical OFDM system based on orthogonal wavelet transform is proposed. In this method, block pilots are periodically inserted into the frame of OFDM signals. At receiver, the phase rotations of pilots are extracted to eliminate common phase difference of each subcarrier. Then, an adaptive equalization is applied to eliminate the phase error inside each subcarrier. Simulation results demonstrate that the proposed method is effective for 100 Gb/s optical binary translation quadrature amplitude modulation (4QAM) OFDM system in which data transmitted over 1000 km with G.652 fiber.%正交频分复用(OFDM)技术加相干接收与数字信号处理法(DSP)的组合是超长距离光通信的理想模型.光OFDM系统对相位噪声十分敏感,必须对相位噪声进行补偿.提出一种基于正交小波基变换的光OFDM系统的联合相位均衡方案.该方案将块状导频周期性地插入OFDM信号,在接收端利用导频信息首先消除各个子载波的公共相位误差,然后采用自适应均衡方式消除每个子载波自身相位误差.仿真结果表明,对于二进制正交振幅键控(4QAM)调制信号,在采用常规的G.652光纤、100 Gb/s的相干光OFDM系统中,该联合相位补偿方法可使信号在满足传输系统的误码性能要求下,传输距离达到1000 km.

  17. Designing Two-Layer Optical Networks with Statistical Multiplexing

    Science.gov (United States)

    Addis, B.; Capone, A.; Carello, G.; Malucelli, F.; Fumagalli, M.; Pedrin Elli, E.

    The possibility of adding multi-protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question that arises is whether it is suitable to have MPLS nodes just at the edge of the network to collect packet traffic from users, or also to introduce MPLS facilities on a subset of the core nodes in order to exploit packet switching flexibility and multiplexing, thus providing induction of a better bandwidth allocation. In this article, we address this complex decisional problem with the support of a mathematical programming approach. We consider two-layer networks where MPLS is overlaid on top of transport networks-synchronous digital hierarchy (SDH) or wavelength division multiplexing (WDM)-depending on the required link speed. The discussions' decisions take into account the trade-off between the cost of adding MPLS support in the core nodes and the savings in the link bandwidth allocation due to the statistical multiplexing and the traffic grooming effects induced by MPLS nodes. The traffic matrix specifies for each point-to-point request a pair of values: a mean traffic value and an additional one. Using this traffic model, the effect of statistical multiplexing on a link allows the allocation of a capacity equal to the sum of all the mean values of the traffic demands routed on the link and only the highest additional one. The proposed approach is suitable to solve real instances in reasonable time.

  18. Multiplexed fibre Fizeau interferometer and fibre Bragg grating sensor system for simultaneous measurement of quasi-static strain and temperature using discrete wavelet transform

    Science.gov (United States)

    Wong, Allan C. L.; Childs, Paul A.; Peng, Gang-Ding

    2006-02-01

    We present a multiplexed fibre Fizeau interferometer (FFI) and fibre Bragg grating (FBG) sensor system for simultaneous measurement of quasi-static strain and temperature. A combined spatial-frequency and wavelength- division multiplexing scheme is employed to multiplex the FFI and FBG sensors. A demodulation technique based on the discrete wavelet transform with signal processing enhancements is used to determine the measurand- induced physical changes of the sensors. The noise associated with the sensor signal is reduced by the block-level-thresholding wavelet denoising method, which is applied via the demodulation technique. This sensor system yields a high accuracy and resolution, and low crosstalk. It is well suited for long-term quasi-static measurements, especially for the structural health monitoring of large-scale structures.

  19. PAWS locker: a passively aligned internal wavelength locker for telecommunications lasers

    Science.gov (United States)

    Boye, Robert R.; Te Kolste, Robert; Kathman, Alan D.; Cruz-Cabrera, Alvaro; Knight, Douglas; Hammond, J. Barney

    2003-11-01

    This paper presents the passively aligned Wavesetter (PAWS) locker: a micro-optic subassembly for use as an internal wavelength locker. As the wavelength spacing in dense wavelength division multiplexing (WDM) decreases, the performance demands placed upon source lasers increase. The required wavelength stability has led to the use of external wavelength lockers utilizing air-spaced, thermally stabilized etalons. However, package constraints are forcing the integration of the wavelength locker directly into the laser module. These etalons require active tuning be done during installation of the wavelength locker as well as active temperature control (air-spaced etalons are typically too large for laser packages). A unique locking technique will be introduced that does not require an active alignment or active temperature compensation. Using the principles of phase shifting interferometry, a locking signal is derived without the inherent inflection points present in the signal of an etalon. The theoretical background of PAWS locker will be discussed as well as practical considerations for its implementation. Empirical results will be presented including wavelength accuracy, alignment sensitivity and thermal performance.

  20. Rigorous Progress on Algorithms Based Routing and Wavelength Assignment in Trans-Egypt Network (TEGYNET Management

    Directory of Open Access Journals (Sweden)

    Abd El–Naser A. Mohammed

    2013-02-01

    Full Text Available In simple wavelength-division multiplexed (WDM networks, a connection must be established along a route using a common wavelength on all of the links along the route. The introduction of wavelength converters into WDM cross connects increases the hardware cost and complexity. Given a set of connection requests, the routing and wavelength assignment problem involves finding a route (routing and assigning a wavelength to each request. This paper has presented the WDM technology is being extensively deployed on point to point links within transport networks in the EGYPT. However, WDM promises advantages for switching and routing as well as for transmission. Optical cross connects are currently being developed which can switch an entire wavelength from an input fiber to an output fiber so that large bandwidth circuits can be routed through the network according to wavelength. High speed, fixed bandwidth, end to end connections called lightpaths can then be established between different nodes. Our suggested Trans-Egypt Network (TEGYNET which uses optical cross connects to route lightpaths through the network are referred to as wavelength routing networks. The average setup time, average link utilization, traffic load, blocking probability, and achievable link utilization in the presence of both single path and multi math routing are the major interesting parameters in the design of TEGYNET topology.

  1. A New Wavelength Optimization and Energy-Saving Scheme Based on Network Coding in Software-Defined WDM-PON Networks

    Science.gov (United States)

    Ren, Danping; Wu, Shanshan; Zhang, Lijing

    2016-09-01

    In view of the characteristics of the global control and flexible monitor of software-defined networks (SDN), we proposes a new optical access network architecture dedicated to Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) systems based on SDN. The network coding (NC) technology is also applied into this architecture to enhance the utilization of wavelength resource and reduce the costs of light source. Simulation results show that this scheme can optimize the throughput of the WDM-PON network, greatly reduce the system time delay and energy consumption.

  2. Demonstration of 5.1 Tbit/s data capacity on a single-wavelength channel.

    Science.gov (United States)

    Hansen Mulvad, Hans Christian; Galili, Michael; Oxenløwe, Leif K; Hu, Hao; Clausen, Anders T; Jensen, Jesper B; Peucheret, Christophe; Jeppesen, Palle

    2010-01-18

    We have generated a single-wavelength data signal with a data capacity of 5.1 Tbit/s. The enabling techniques to generate the data signal are optical time-division multiplexing up to a symbol rate of 1.28 Tbaud, differential quadrature phase shift keying as data format, and polarisation-multiplexing. For the first time, error-free performance with a bit error rate less than 10(-9) is demonstrated for the 5.1 Tbit/s data signal. This is achieved in a back-to-back configuration using a direct detection receiver based on polarisation- and time-demultiplexing, delay-demodulation and balanced photo-detection.

  3. Multiplexing technique for computer communications via satellite channels

    Science.gov (United States)

    Binder, R.

    1975-01-01

    Multiplexing scheme combines technique of dynamic allocation with conventional time-division multiplexing. Scheme is designed to expedite short-duration interactive or priority traffic and to delay large data transfers; as result, each node has effective capacity of almost total channel capacity when other nodes have light traffic loads.

  4. ROUTING AND WAVELENGTH ASSIGNMENT ALGORITHMS BASED ON EQUIVALENT NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Qi Xiaogang; Liu Lifang; Lin Sanyang

    2006-01-01

    In this paper, a Wavelength Division Multiplexing (WDM) network model based on the equivalent networks is described, and wavelength-dependent equivalent arc, equivalent networks, equivalent multicast tree and some other terms are presented. Based on this model and relevant Routing and Wavelength Assignment (RWA) strategy, a unicast RWA algorithm and a multicast RWA algorithm are presented. The wavelength-dependent equivalent arc expresses the schedule of local RWA and the equivalent network expresses the whole topology of WDM optical networks, so the two algorithms are of the flexibility in RWA and the optimization of the whole problem. The theoretic analysis and simulation results show the two algorithms are of the stronger capability and the lower complexity than the other existing algorithms for RWA problem, and the complexity of the two algorithms are only related to the scale of the equivalent networks. Finally, we prove the two algorithms' feasibility and the one-by-one corresponding relation between the equivalent multicast tree and original multicast tree, and point out the superiorities and drawbacks of the two algorithms respectively.

  5. A nano/micro `meso' scale self-calibrating integrated optical wavelength and intensity meter

    Science.gov (United States)

    Caulfield, H. J.; Zavalin, A.

    2006-07-01

    Wavelength-division multiplexing has become the dominant approach to utilizing the massive bandwidth of optical fibers and integrated optics, including those based on a photonic crystal approach and recent nanotechnology achievements. For tunable sources and tunable receivers, it is desirable to measure the wavelength accurately and quickly. Unfortunately, current wavelength-measurement devices are not integrated and not fast enough to support 1 Gbit/s and higher requirements of the modern communication lines. We show here how to make an integrated optical system that results in an intensity-independent wavelength determination and a wavelength-independent intensity determination at ultra-short pulse duration or higher than ˜1-GHz bandwidth. The two output beams from a Mach-Zehnder interferometer, tuned to 3 dB at each output at the beginning of the wavelength-measurement range, provide all of the needed information. We show how a simple fast wavelength meter can be built into a silicon - or other - optical chip. It employs fuzzy metrology using both outputs of an integrated interferometer.

  6. Coupled-resonator-induced-transparency concept for wavelength routing applications.

    Science.gov (United States)

    Mancinelli, M; Guider, R; Bettotti, P; Masi, M; Vanacharla, M R; Pavesi, L

    2011-06-20

    The presence of coupled resonators induced transparency (CRIT) effects in side-coupled integrated spaced sequence of resonators (SCISSOR) of different radii has been studied. By controlling the rings radii and their center to center distance, it is possible to form transmission channels within the SCISSOR stop-band. Two different methods to exploit the CRIT effect in add/drop filters are proposed. Their performances, e. g. linewidth, crosstalk and losses, are examined also for random variations in the structural parameters. Finally, few examples of high performances mux/demux structures and 2 × 2 routers based on these modified SCISSOR are presented. CRIT based SCISSOR optical devices are particularly promising for ultra-dense wavelength division multiplexing applications.

  7. Experimental multiplexing of quantum key distribution with classical optical communication

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liu-Jun; Chen, Luo-Kan; Ju, Lei [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xu, Mu-Lan; Zhao, Yong [Quantum Communication Technology Co., Ltd., Anhui, Hefei, Anhui 230088 (China); Chen, Kai; Chen, Zeng-Bing; Chen, Teng-Yun, E-mail: tychen@ustc.edu.cn; Pan, Jian-Wei [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2015-02-23

    We demonstrate the realization of quantum key distribution (QKD) when combined with classical optical communication, and synchronous signals within a single optical fiber. In the experiment, the classical communication sources use Fabry-Pérot (FP) lasers, which are implemented extensively in optical access networks. To perform QKD, multistage band-stop filtering techniques are developed, and a wavelength-division multiplexing scheme is designed for the multi-longitudinal-mode FP lasers. We have managed to maintain sufficient isolation among the quantum channel, the synchronous channel and the classical channels to guarantee good QKD performance. Finally, the quantum bit error rate remains below a level of 2% across the entire practical application range. The proposed multiplexing scheme can ensure low classical light loss, and enables QKD over fiber lengths of up to 45 km simultaneously when the fibers are populated with bidirectional FP laser communications. Our demonstration paves the way for application of QKD to current optical access networks, where FP lasers are widely used by the end users.

  8. Coherence-Multiplexed Optical RF Feeder Networks

    NARCIS (Netherlands)

    Meijerink, Arjan; Taniman, Robert O.; Etten, van Wim

    2007-01-01

    An optical RF feeding system for wireless access is proposed, in which the radio access points are distinguished by means of coherence multiplexing (CM). CM is a rather unknown and potentially inexpensive optical code division multiple access technique, which is particularly suitable for relatively

  9. Dynamic Wavelength and Bandwidth Allocation Using Adaptive Linear Prediction in WDM/TDM Ethernet Passive Optical Networks

    Institute of Scientific and Technical Information of China (English)

    LU Yi-yi; GUO Yong; HE Chen

    2009-01-01

    Hybrid wavelength-division-multiplexing (WDM)/time-division-multiplexing (TDM) ethernet passive optical networks (EPONs) can achieve low per-subscriber cost and scalability to increase the number of subscribers. This paper discusses dynamic wavelength and bandwidth allocation (DWBA) algorithm in hybrid WDM/TDM EPONs. Based on the correlation structure of the variable bit rate (VBR) video traffic, we propose a quality-of-service (QoS) supported DWBA using adaptive linear traffic prediction. Wavelength and timeslot are allocated dynamically by optical line terminal (OLT) to all optical network units (ONUs) based on the bandwidth requests and the guaranteed service level agreements (SLA) of all ONUs. Mean square error of the predicted average arriv-ing rate of compound video traffic during waiting period is minimized through Wiener-Hopf equation. Simulation results show that the DWBA-adaptive-linear-prediction (DWBA-ALP) algorithm can significantly improve the QoS performances in terms of low delay and high bandwidth utilization.

  10. Conversion of asynchronous 10 Gbit/s Ethernet NRZ frame into a synchronous RZ frame and multiplexing to 170 Gbit/s

    DEFF Research Database (Denmark)

    Laguardia Areal, Janaina; Hu, Hao; Palushani, Evarist

    2010-01-01

    This paper presents an optical circuit for frame synchronization and pulse compression of 10G Ethernet frames with 12000 bits and multiplexing to a 170 Gbit/s optical time division multiplexed data stream.......This paper presents an optical circuit for frame synchronization and pulse compression of 10G Ethernet frames with 12000 bits and multiplexing to a 170 Gbit/s optical time division multiplexed data stream....

  11. Internet Protocol-Hybrid Opto-Electronic Ring Network (IP-HORNET): A Novel Internet Protocol-Over-Wavelength Division Multiplexing (IP-Over-WDM) Multiple-Access Metropolitan Area Network (MAN)

    Science.gov (United States)

    2003-04-01

    Technology, STMicroelectronics. 0020-0255/02/$ - see front matter 2002 Elsevier Science Inc . All rights reserved. PII: S0020 -0255 (02 )00250 -5 233...scheduling algorithms. 2002 Elsevier Science Inc . All rights reserved. Keywords: Scheduling; Unslotted CSMA/CA with backoff; MAC; RS; LQF; DPQ; SPF; WDM

  12. 波分复用技术在实现双向改造中的应用%Wavelength Division Multiplexing Technique and its Application in the Realization of Bi-Directional Transformation

    Institute of Scientific and Technical Information of China (English)

    阮邦耀; 陈明希

    2012-01-01

    DWDM和CWDM技术是WDM技术的两种方式,其通过在一芯光纤中传输多路光波来实现光通信网络容量的扩展、提升光信道的利用率。文章通过对DWDM技术优点、技术分类和发展现状的介绍,以及通过对于DWDM和CWDM技术在福州双向网络改造中的应用,来探讨如何在不改变现有光网络结构的基础上,实现网络容量提升,满足用户日益增长的需求。%DWDM and CWDM technology are two ways of WDM technology,through multi-channel optical transmission in a core fiber to achieve upgrading of optical communication network capacity,enhance the utilization of optical channel.This article introduced the DWDM technology advantages,technical classification and the development situation,as well as the DWDM and CWDM technology in Fuzhou bi-directional network transformation application,to explore how to achieve network capacity upgrade and to meet the growing demands of users on the basis of not change the existing optical network structure.

  13. 80-Channel Multiplexer-Demultiplexer Module for DWDM Communications using Hybrid AWG -- Interleaver Technology

    Science.gov (United States)

    Rablau, Corneliu; Bredthauer, Lance

    2007-10-01

    Aside from the more traditional data, voice and e-mail communications, new bandwidth intensive applications in the larger consumer markets, such as music, digital pictures and movies, have led to an explosive increase in the demand for transmission capacity for optical communications networks. This has resulted in a widespread deployment of Dense Wavelength Division Multiplexing (DWDM) as a means of increasing the communications capacity by multiplexing and transmitting signals of different wavelengths (establishing multiple communication channels) through a single strand of fiber. We report on the design, assembly and characterization of a 50-GHz, 80-channel Mux-Demux module for DWDM systems. The module has been assembled from two commercially available 100 GHz, 40-channel Array Waveguide Grating (AWG) modules and a 50-GHz to 100-GHz interleaver. Relevant performance parameters such as insertion loss, channel uniformity, next-channel isolation (crosstalk) and integrated cross-talk are presented and discussed in contrast with the performance of other competing technologies such as Thin-Film-Filter-based Mux-Demux devices.

  14. Towards a versatile active wavelength converter for all-optical networks based on quasi-phase matched intra-cavity difference-frequency generation.

    Science.gov (United States)

    Torregrosa, Adrián J; Maestre, Haroldo; Capmany, Juan

    2013-11-18

    The availability of reconfigurable all-optical wavelength converters for an efficient and flexible use of optical resources in WDM (wavelength division multiplexing) networks is still lacking at present. We propose and report preliminary results on a versatile active technique for multiple and tunable wavelength conversions in the 1500-1700 nm spectral region. The technique is based on combining broadband quasi-phase matched intra-cavity parametric single-pass difference-frequency generation close to degeneracy in a diode-pumped tunable laser. A periodically poled stoichiometric lithium tantalate crystal is used as the nonlinear medium, with a parametric pump wave generated in a continuous-wave self-injection locked Cr3+:LiCAF tunable laser operating at around 800 nm.

  15. A wavelength tunable ONU transmitter based on multi-mode Fabry-Perot laser and micro-ring resonator for bandwidth symmetric TWDM-PON

    Science.gov (United States)

    Gao, Zhensen; Sun, Xiao; Zhang, Kaibin

    2016-02-01

    Wavelength tunable optical transmitter is an essential component for the newly standardized time and wavelength division multiplexed passive optical network (TWDM-PON), where tunable ONU with 10Gb/s bit rate is desired to provide 40Gb/s symmetric bandwidth. In this paper, a novel wavelength tunable optical transmitter is proposed by reusing legacy low speed multi-mode Fabry-Perot laser and connecting it with an integrated photonic chip with two coupled micro-ring resonators to generate a tunable single mode signal based on Vernier effect for 10Gb/s high speed modulation, which makes it as a promising solution for colorless ONU in future symmetric TWDM-PON.

  16. The Available Options for Wavelength Group Selection and Transceiver Design for Next Generation PON Stage 2 (NG-PON2)

    Science.gov (United States)

    Niazi, Shahab Ahmad; Zhang, Xiaoguang; Xi, Lixia; Chen, Yong Li; Idress, Muhammad

    2013-09-01

    The full service access network (FSAN) task group meeting was held in April 2012, where they agreed to adopt time and wavelength division multiplexed passive optical network (TWDM-PON) as a primary solution to NG-PON2. Major requirements includes at least 40 Gbit/s aggregate rate in downstream, 1:64 split ratio, 40 km differential reach, and at least 1 Gb/s access rate per optical network unit (ONU). In this paper, a performance analysis will be carried out for downstream 4-wavelengths group selection from S-band, L-band, and C-band. A comparison for optimal transmitter design is also investigated among probable options of chirp managed laser diode, Lithium Niobate (LiNbo3) Mach Zehnder modulator, besides examining tunable transceivers in contrary to remotely fed colorless ONUs.

  17. An 8-Channel Wavelength MMI Demultiplexer in Slot Waveguide Structures

    Directory of Open Access Journals (Sweden)

    Bar Baruch Ben Zaken

    2016-11-01

    Full Text Available We propose a novel 8-channel wavelength multimode interference (MMI demultiplexer in slot waveguide structures that operate at 1530 nm, 1535 nm, 1540 nm, 1545 nm, 1550 nm, 1555 nm, 1560 nm, and 1565 nm. Gallium nitride (GaN surrounded by silicon (Si was found to be a suitable material for the slot-waveguide structures. The proposed device was designed by seven 1 × 2 MMI couplers, fourteen S-bands, and one input taper. Numerical investigations were carried out on the geometrical parameters using a full vectorial-beam propagation method (FV-BPM. Simulation results show that the proposed device can transmit 8-channel that works in the whole C-band (1530–1565 nm with low crosstalk (−19.97–−13.77 dB and bandwidth (1.8–3.6 nm. Thus, the device can be very useful in optical networking systems that work on dense wavelength division multiplexing (DWDM technology.

  18. Multiplexity and multireciprocity in directed multiplexes

    CERN Document Server

    Gemmetto, Valerio; Picciolo, Francesco; Ruzzenenti, Franco; Garlaschelli, Diego

    2014-01-01

    In the last few years, the study of multi-layer complex networks has received significant attention. In this work, we provide new measures to analyse dependencies between directed links in different layers of multiplex networks. We show that this requires more than a straightforward extension of the corresponding multiplexity measures that have been developed for undirected multiplexes. In particular, one should take into account the effects of reciprocity, i.e. the tendency of pairs of vertices to establish mutual connections. It is well known that reciprocity is a crucial property of many directed single-layer networks, affecting several dynamical processes taking place on such systems. Here we extend this quantity to directed multiplexes and introduce the notion of multireciprocity, defined as the tendency of links in one layer to be reciprocated by links in a different layer. We introduce multireciprocity measures valid for both binary and weighted networks and then validate these novel quantities on the ...

  19. Sandpiles on multiplex networks

    CERN Document Server

    Lee, Kyu-Min; Kim, I -M

    2011-01-01

    We introduce the sandpile model on multiplex networks with more than one type of edges and investigate its scaling and dynamical behaviors. We find that the introduction of multiplexity does not alter the scaling behavior of avalanche dynamics; the system is critical with the asymptotic power-law avalanche size distribution with exponent $\\tau = 3/2$ on duplex random networks. Detailed cascade dynamics, however, is affected by the multiplex coupling. For example, higher-degree nodes such as hubs in scale-free networks fail more often in the multiplex dynamics than in the simplex network counterpart in which different types of edges are simply aggregated. Our results suggest that multiplex modeling would be necessary in order to gain better understanding of cascading failure phenomena of real-world multiplex complex systems, such as the global economic crisis.

  20. Weighted Multiplex Networks

    CERN Document Server

    Menichetti, Giulia; Panzarasa, Pietro; Mondragón, Raúl J; Bianconi, Ginestra

    2013-01-01

    One of the most important challenges in network science is to quantify the information encoded in complex network structures. Disentangling randomness from organizational principles is even more demanding when networks have a multiplex nature. Multiplex networks are multilayer systems of $N$ nodes that can be linked in multiple interacting and co-evolving layers. In these networks, relevant information might not be captured if the single layers were analyzed separately. Here we demonstrate that such partial analysis of layers fails to capture significant correlations between weights and topology of complex multiplex networks. To this end, we study two weighted multiplex co-authorship and citation networks involving the authors included in the American Physical Society. We show that in these networks weights are strongly correlated with multiplex structure, and provide empirical evidence in favor of the advantage of studying weighted measures of multiplex networks, such as multistrength and the inverse multipa...

  1. Mode-Division-Multiplexing of Multiple Bessel-Gaussian Beams Carrying Orbital-Angular-Momentum for Obstruction-Tolerant Free-Space Optical and Millimetre-Wave Communication Links.

    Science.gov (United States)

    Ahmed, Nisar; Zhao, Zhe; Li, Long; Huang, Hao; Lavery, Martin P J; Liao, Peicheng; Yan, Yan; Wang, Zhe; Xie, Guodong; Ren, Yongxiong; Almaiman, Ahmed; Willner, Asher J; Ashrafi, Solyman; Molisch, Andreas F; Tur, Moshe; Willner, Alan E

    2016-03-01

    We experimentally investigate the potential of using 'self-healing' Bessel-Gaussian beams carrying orbital-angular-momentum to overcome limitations in obstructed free-space optical and 28-GHz millimetre-wave communication links. We multiplex and transmit two beams (l = +1 and +3) over 1.4 metres in both the optical and millimetre-wave domains. Each optical beam carried 50-Gbaud quadrature-phase-shift-keyed data, and each millimetre-wave beam carried 1-Gbaud 16-quadrature-amplitude-modulated data. In both types of links, opaque disks of different sizes are used to obstruct the beams at different transverse positions. We observe self-healing after the obstructions, and assess crosstalk and power penalty when data is transmitted. Moreover, we show that Bessel-Gaussian orbital-angular-momentum beams are more tolerant to obstructions than non-Bessel orbital-angular-momentum beams. For example, when obstructions that are 1 and 0.44 the size of the l = +1 beam, are placed at beam centre, optical and millimetre-wave Bessel-Gaussian beams show ~6 dB and ~8 dB reduction in crosstalk, respectively.

  2. All-optical wavelength conversion by four-wave mixing in a semiconductor optical amplifier

    Science.gov (United States)

    Lee, Robert Bumju

    1997-11-01

    Wavelength division multiplexed optical communication systems will soon become an integral part of commercial optical networks. A crucial new function required in WDM networks is wavelength conversion, the spectral translation of information-laden optical carriers, which enhances wavelength routing options and greatly improves network reconfigurability. One of several techniques for implementing this function is four-wave mixing utilizing ultra-fast intraband nonlinearities in semiconductor optical amplifiers. The effects of input power, noise prefiltering and semiconductor optical amplifier length on the conversion efficiency and optical signal-to-noise ratio were examined. Systems experiments have been conducted in which several important performance characteristics of the wavelength converter were studied. A bit-error-rate performance of BER performance were studied at 2.5 Gb/s for both a single-channel conversion and a simultaneous 2-channel conversion. The crosstalk penalty induced by parasitic cross-gain modulation in 2-channel conversion is quantified. The spectral inversion which results from the conversion process is studied by time-resolved spectral analysis, and its application as a technique for dispersion compensation is demonstrated. Finally, the application of selective organometallic vapor-phase epitaxy for the formation of highly-uniform and densely-packed arrays of GaAs quantum dots is demonstrated. GaAs dots of 15-20 nm in base diameter and 8-10 nm in height terminated by slow-growth crystallographic planes were grown within dielectric-mask openings and characterized by atomic force microscopy.

  3. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  4. Wavelength Tuning Free Transceiver Module in OLT Downstream Multicasting 4λ × 10 Gb/s TWDM-PON System

    Directory of Open Access Journals (Sweden)

    M. S. Salleh

    2014-01-01

    Full Text Available We propose a new architecture of dynamic time-wavelength division multiplexing-passive optical network (TWDM-PON system that employs integrated all-optical packet routing (AOPR module using 4λ×10 Gbps downstream signal to support 20 km fiber transmission. This module has been designed to support high speed L2 aggregation and routing in the physical layer PON system by using multicasting cross-gain modulation (XGM to route packet from any PON port to multiple PON links. Meanwhile, the fixed wavelength optical line terminal (OLT transmitter with wavelength tuning free features has been designed to integrate with the semiconductor optical amplifier (SOA and passive arrayed waveguide grating (AWG. By implementing hybrid multicasting and multiplexing, the system has been able to support a PON system with full flexibility function for managing highly efficient dynamic bandwidth allocation to support the 4λ×10 Gb/s TWDM-PON system used to connect 4 different PON links using fixed wavelength OLT transceivers with maximum 38 dB link loss.

  5. Control of Angular Intervals for Angle-Multiplexed Holographic Memory

    Science.gov (United States)

    Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki

    2009-03-01

    In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

  6. Single and Multicasting Inverted-Wavelength Conversion at 80 Gb/s Based on a Single Semiconductor Optical Amplifier

    Institute of Scientific and Technical Information of China (English)

    HUANG Xi; QIN Cui; YU Yu; ZHANG Xin-Liang

    2011-01-01

    We experimentally demonstrate single and multicasting inverted wavelength conversion at 80Gb/s by using the cross-gain modulation and cross-phase modulation in a single semiconductor optical amplifier (SOA).In all the cases,converted signals with a high extinction ratio (ER) and large eye opening are obtained.For singlechannel wavelength conversion,the ER of the output signal is as high as 30.10dB.For three-channel wavelength multicasting,high quality converted signals could also be observed.The ERs with three channels are 21.54 dB,18.58dB and 17.72dB,respectively.Thus,one- and three-channel wavelength conversion with high performance can be achieved by using a single quantum-well SOA.All-optical wavelength conversion (AOWC).[1-4] is a key technology in wavelength division multiplexed (WDM) networks.AOWC based on semiconductor optical amplifiers (SOAs) is widely used due to its potential integration and power efficieney.Many SOAbased AOWCs have been theoretically and experimentally demonstrated.[5,6] Furthermore,wavelength multicasting is very important in all optical signal processing systems.Wavelength multicasting is a signal processing function that can be used to transfer the information carried by a channel at a certain input wavelength on different output wavelengths.Recently,many methods have been proposed for single wavelength conversion and wavelength multieasting.High nonlinear fibers,electro-absorption modulators and SOAs[7] have been used as nonlinear media.How ever,most of the schemes suffer from drawbacks such as complex architecture,a fairly high optical input power requirement,polarization dependence and so on.%We experimentally demonstrate single and multicasting inverted wavelength conversion at 80Gb/s by using the cross-gain modulation and cros-phase modulation in a single semiconductor optical amplifier (SOA). In all the cases, converted signals with a high extinction ratio (ER) and largo eye opening are obtained. For single-channel wavelength

  7. 基于小波变换的长距离光正交频分复用系统中四波混频引起的相位噪声分析%Analysis of Phase Noise Induced by Four-Wave Mixing in Long-Haul Optical Orthogonal Frequency-Division Multiplexing Based on Wavelet Transforms

    Institute of Scientific and Technical Information of China (English)

    高海越; 潘炜

    2012-01-01

    四波混频(FWM)效应是相干光正交频分复用(CO-OFDM)系统中最主要的非线性作用.分析基于小波变换的相干光正交频分(WT-OOFDM)系统原理,研究小波变换对FWM效应和光放大器自发辐射(ASE)引起的相位噪声的改善效果.数值结果表明,在采用常规G.652光纤,100 Gbit/s的WT-OOFDM传输1500 km时,非线性相位噪声降低20%,总相位噪声降低15%.%Four-wave mixing (FWM) is the most important nonlinear effect in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system. The principle of CO-OFDM system based on wavelet transforms (WT-OOFDM) is analyzed, and effect of wavelet transforms on phase noise caused by FWM and amplified spontaneous emission CASE) of optical amplifiers is discussed. For the conventional optical fiber G. 652, 100 Gbit/s WT-OOFDM system, the simulation results show that the variance of the total phase noise can be decreased by 15% , and the nonlinear phase noise has a 20% reduction while the transmission distance reaches 1500 km.

  8. Multiplexed FBG Monitoring System for Forecasting Coalmine Water Inrush Disaster

    Directory of Open Access Journals (Sweden)

    B. Liu

    2012-01-01

    Full Text Available This paper presents a novel fiber-Bragg-grating- (FBG- based system which can monitor and analyze multiple parameters such as temperature, strain, displacement, and seepage pressure simultaneously for forecasting coalmine water inrush disaster. The sensors have minimum perturbation on the strain field. And the seepage pressure sensors adopt a drawbar structure and employ a corrugated diaphragm to transmit seepage pressure to the axial strain of FBG. The pressure sensitivity is 20.20 pm/KPa, which is 6E3 times higher than that of ordinary bare FBG. The FBG sensors are all preembedded on the roof of mining area in coalmine water inrush model test. Then FBG sensing network is set up applying wavelength-division multiplexing (WDM technology. The experiment is carried out by twelve steps, while the system acquires temperature, strain, displacement, and seepage pressure signals in real time. The results show that strain, displacement, and seepage pressure monitored by the system change significantly before water inrush occurs, and the strain changes firstly. Through signal fusion analyzed it can be concluded that the system provides a novel way to forecast water inrush disaster successfully.

  9. Analysis of Performance Limitations in Fiber Bragg Grating Based Optical Add-Drop Multiplexer due to Crosstalk

    Directory of Open Access Journals (Sweden)

    Md. Mahiuddin

    2012-03-01

    Full Text Available Abstract— Wavelength  division  multiplexing  (WDM optical networks  are  attracting  more  and  more attention because of their ability to provide  increased capacity and  flexibility. Optical add-drop multiplexer (OADM  becomes  a  key  component  to  add  or  drop wavelengths  in  high  bit  rate  optical  networks. Crosstalk  in OADM  often degrades  the performance of WDM  system  drastically.  In  this  article,  we  have developed  analytical model  for  low  crosstalk  of  fiber Bragg  grating  based  OADM  with  isolator. We  have also  derived  analytical  expressions  for  relative intensity noise (RIN, bit error rate (BER and power penalty to evaluate the performance limitations of this OADM. Results show that crosstalk, RIN and BER of the  proposed  OADM  are significantly  lower  and provide better performance than the existing OADMs.

  10. Preface to the special issue on next-generation multiplexing schemes in fiber-based systems

    Science.gov (United States)

    Sillard, Pierre; Essiambre, René-Jean; Jung, Yongmin; Yamamoto, Takashi

    2017-02-01

    Since the beginning of optical communications in the late 70s, capacity has kept up with the exponential growth of traffic demand. This has been enabled by many technologies among which the most up-to-date wavelength multiplexing combined with coherent detection of polarized-multiplexed quadrature-amplitude-modulated signals. There is, however, a growing realization that this might no longer be sufficient and that next-generation multiplexing schemes are needed to avoid an imminent capacity crunch.

  11. On-chip single photon filtering and multiplexing in hybrid quantum photonic circuits.

    Science.gov (United States)

    Elshaari, Ali W; Zadeh, Iman Esmaeil; Fognini, Andreas; Reimer, Michael E; Dalacu, Dan; Poole, Philip J; Zwiller, Val; Jöns, Klaus D

    2017-08-30

    Quantum light plays a pivotal role in modern science and future photonic applications. Since the advent of integrated quantum nanophotonics different material platforms based on III-V nanostructures-, colour centers-, and nonlinear waveguides as on-chip light sources have been investigated. Each platform has unique advantages and limitations; however, all implementations face major challenges with filtering of individual quantum states, scalable integration, deterministic multiplexing of selected quantum emitters, and on-chip excitation suppression. Here we overcome all of these challenges with a hybrid and scalable approach, where single III-V quantum emitters are positioned and deterministically integrated in a complementary metal-oxide-semiconductor-compatible photonic circuit. We demonstrate reconfigurable on-chip single-photon filtering and wavelength division multiplexing with a foot print one million times smaller than similar table-top approaches, while offering excitation suppression of more than 95 dB and efficient routing of single photons over a bandwidth of 40 nm. Our work marks an important step to harvest quantum optical technologies' full potential.Combining different integration platforms on the same chip is currently one of the main challenges for quantum technologies. Here, Elshaari et al. show III-V Quantum Dots embedded in nanowires operating in a CMOS compatible circuit, with controlled on-chip filtering and tunable routing.

  12. Low complexity digital backpropagation for high baud subcarrier-multiplexing systems.

    Science.gov (United States)

    Zhang, Fangyuan; Zhuge, Qunbi; Qiu, Meng; Plant, David V

    2016-07-25

    In this paper, we propose two modifications to reduce the complexity of the subcarrier-multiplexing (SCM) based digital backpropagation (DBP) for high symbol rate SCM systems. The first one is to reduce the number of interfering subcarriers (RS-SCM-DBP) when evaluating the cross-subcarrier nonlinearity (CSN). The second one is to replace the original frequency domain CSN filters with the infinite impulse response (IIR) filters (IIR-RS-SCM-DBP) in the CSN compensation. The performance of the proposed schemes are numerically evaluated in three-channel dual-polarization (DP) 16QAM wavelength-division multiplexing (WDM) transmissions. The aggregate symbol rate for each channel is 120 GBaud and the transmission distance is 1600 km. For the SCM system with 16 subcarriers, the IIR-RS-SCM-DBP with only 4 interfering subcarriers and 2 steps can achieve a 0.3 dB Q-factor improvement in the WDM transmission. Compared to the original SCM-DBP, the proposed IIR-RS-SCM-DBP reduces the complexity by 48% at a performance loss of only 0.07 dB.

  13. Multiplexity and multireciprocity in directed multiplexes

    Science.gov (United States)

    Gemmetto, Valerio; Squartini, Tiziano; Picciolo, Francesco; Ruzzenenti, Franco; Garlaschelli, Diego

    2016-10-01

    Real-world multilayer networks feature nontrivial dependencies among links of different layers. Here we argue that if links are directed, then dependencies are twofold. Besides the ordinary tendency of links of different layers to align as the result of "multiplexity," there is also a tendency to antialign as a result of what we call "multireciprocity," i.e., the fact that links in one layer can be reciprocated by opposite links in a different layer. Multireciprocity generalizes the scalar definition of single-layer reciprocity to that of a square matrix involving all pairs of layers. We introduce multiplexity and multireciprocity matrices for both binary and weighted multiplexes and validate their statistical significance against maximum-entropy null models that filter out the effects of node heterogeneity. We then perform a detailed empirical analysis of the world trade multiplex (WTM), representing the import-export relationships between world countries in different commodities. We show that the WTM exhibits strong multiplexity and multireciprocity, an effect which is, however, largely encoded into the degree or strength sequences of individual layers. The residual effects are still significant and allow us to classify pairs of commodities according to their tendency to be traded together in the same direction and/or in opposite ones. We also find that the multireciprocity of the WTM is significantly lower than the usual reciprocity measured on the aggregate network. Moreover, layers with low (high) internal reciprocity are embedded within sets of layers with comparably low (high) mutual multireciprocity. This suggests that, in the WTM, reciprocity is inherent to groups of related commodities rather than to individual commodities. We discuss the implications for international trade research focusing on product taxonomies, the product space, and fitness and complexity metrics.

  14. Multiplex tokamak power plant

    Energy Technology Data Exchange (ETDEWEB)

    Dabiri, A.E.

    1986-07-01

    The concept of multiplexing for a fusion power core as an option for producing power is explored. Superconducting, as well as normal magnet, coils in either first or second stability regimes are considered. The results show that multiplex plants with superconducting magnets operating in the second stability regime could be competitive with the single-unit plants in some unit sizes. The key issues that impact the expected benefits of multiplexing must be investigated further. These are factory fabrication, economy of scale, the extent of equipment sharing, inherent safety, maintainability, and utility load management.

  15. A WDM-PON with DPSK modulated downstream and OOK modulated upstream signals based on symmetric 10 Gbit/s wavelength reused bidirectional reflective SOA

    Science.gov (United States)

    El-Nahal, Fady I.

    2017-01-01

    We investigate a wavelength-division-multiplexing passive optical network (WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying (DPSK) downstream signals and on-off keying (OOK) upstream signals, respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier (RSOA) as an intensity modulator at the optical network unit (ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio ( ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate ( BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.

  16. Wavelength conversion, time demultiplexing and multicasting based on cross-phase modulation and four-wave mixing in dispersion-flattened highly nonlinear photonic crystal fiber

    Science.gov (United States)

    Hui, Zhan-Qiang; Zhang, Jian-Guo

    2012-05-01

    We propose the use of cross-phase modulation (XPM) and four-wave mixing (FWM) in dispersion-flattened highly nonlinear photonic crystal fibers (HNL-PCFs) to implement the functionalities of wavelength conversion, simultaneous time demultiplexing and wavelength multicasting in optical time-division multiplexing (OTDM) systems. The experiments on wavelength conversion at 80 Gbit s-1and OTDM demultiplexing from 80 to 10 Gbit s-1 with wavelength multicasting of two channels are successfully demonstrated to validate the proposed scheme, which are carried out by using two segments of dispersion-flattened HNL-PCFs with lengths of 100 and 50 m, respectively. Moreover, the bit error rate (BER) performance is also measured. The results show that our designed system can achieve a power penalty of less than 4.6 dB for two multicasting channels with a 24 nm wavelength span at the BER of 10-9 when compared with the 10 Gbit/s back-to-back measurement. The proposed system is transparent to bit rate since only an ultrafast third-order nonlinear effect is used. The resulting configuration is compact, robust and reliable, benefiting from the use of dispersion-flattened HNL-PCFs with short lengths. This also makes the proposed system more flexible in the operational wavelengths than those based on dispersion-shifted fibers and traditional highly nonlinear fibers. The work was supported in part by the CAS/SAFEA International Partnership Program for Creative Research Teams.

  17. New RoF-PON architecture using polarization multiplexed wireless MIMO signals for NG-PON

    Science.gov (United States)

    Elmagzoub, M. A.; Mohammad, Abu Bakar; Shaddad, Redhwan Q.; Al-Gailani, Samir A.

    2015-06-01

    Next-generation access networks require provision of wireless services and high data rate to meet the huge demands for mobility and multiple services. Moreover, reusing the currently deployed optical distribution networks (ODNs) is highly beneficial and cost effective for providing the new high data rate wireless demands. In this paper, bidirectional radio over fiber passive optical network (RoF-PON) capable of handling multiple-input-multiple-output (MIMO) streams at low cost, high spectral efficiency and backward compatibility with currently deployed PON, is proposed. To the best of our knowledge, all the existing RoF MIMO solutions have not considered compatibility with currently deployed ODNs. Eight laser diodes (LDs) at the central office (CO) are enough for the whole system, instead of having LD or optical transmitter at each remote antenna unit (RAU), which makes a colorless and cost-effective RAU. Twenty four wavelengths are generated using optical comb technique. Each two 16-QAM MIMO signals that have the same carrier frequency in the downstream (DS) transmission are optically combined using polarization-division-multiplexing (PDM), where each two upstream (US) MIMO signals are time division multiplexed. The PDM configuration doubles spectral efficiency with a power penalty of only 1.5 dB. The proposed architecture is a bidirectional asymmetric RoF-PON with total 40/10 Gb/s for DS/US transmission. Even after transmission over 20 km SMF and splitting ratio of 32, acceptable transmission performance and widely separated constellation diagrams for the 16-QAM signals are achieved, with bit error rate (BER) of 10-6 for DS signals and 10-3 for the US signals which can be reduced down to 10-6 by using forward error correction (FEC).

  18. Fighting Divisions

    Science.gov (United States)

    1945-12-01

    when it hit the beaches of Morotai to open the drive that later led to the liberation of the Philippines, its Doughboys were alternately whistling...the Dixie Division sailed from Maffin Bay for the reconquest of Morotai , and on the 15th of the month hit the beaches of this Dutch island, less than...quickly secured a beachhead and by noon of D-day had seized Pitoe Airdrome. Morotai gave our forces control of the Halma- hera Sea and cut off 20,000

  19. Multiplexing technique using amplitude-modulated chirped fiber Bragg gratings

    Science.gov (United States)

    Wong, Allan C. L.; Childs, Paul A.; Peng, Gang-Ding

    2007-07-01

    We propose a new multiplexing technique using amplitude-modulated chirped fiber Bragg gratings that have an identical center Bragg wavelength. Each grating is inscribed with a unique amplitude modulation that allows them to be multiplexed with complete overlapping within a certain bandwidth. To demodulate the multiplexed signal, the discrete wavelet transform is employed. Concurrently, a wavelet denoising technique is used to reduce the noise. This proposed multiplexing technique has been verified through strain measurements. Experimental results showed that for strains applied up to 1250 μɛ the absolute error and cross-talk are within ±20 μɛ and 16 μɛ, respectively. A strain resolution of 4 μɛ is obtained.

  20. Preliminary Assessment of Microwave Readout Multiplexing Factor

    Energy Technology Data Exchange (ETDEWEB)

    Croce, Mark Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koehler, Katrina Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rabin, Michael W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, D. A. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Mates, J. A. B. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Gard, J. D. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Becker, D. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Schmidt, D. R. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Ullom, J. N. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States)

    2017-01-23

    Ultra-high resolution microcalorimeter gamma spectroscopy is a new non-destructive assay technology for measurement of plutonium isotopic composition, with the potential to reduce total measurement uncertainty to a level competitive with destructive analysis methods [1-4]. Achieving this level of performance in practical applications requires not only the energy resolution now routinely achieved with transition-edge sensor microcalorimeter arrays (an order of magnitude better than for germanium detectors) but also high throughput. Microcalorimeter gamma spectrometers have not yet achieved detection efficiency and count rate capability that is comparable to germanium detectors, largely because of limits from existing readout technology. Microcalorimeter detectors must be operated at low temperature to achieve their exceptional energy resolution. Although the typical 100 mK operating temperatures can be achieved with reliable, cryogen-free systems, the cryogenic complexity and heat load from individual readout channels for large sensor arrays is prohibitive. Multiplexing is required for practical systems. The most mature multiplexing technology at present is time-division multiplexing (TDM) [3, 5-6]. In TDM, the sensor outputs are switched by applying bias current to one SQUID amplifier at a time. Transition-edge sensor (TES) microcalorimeter arrays as large as 256 pixels have been developed for X-ray and gamma-ray spectroscopy using TDM technology. Due to bandwidth limits and noise scaling, TDM is limited to a maximum multiplexing factor of approximately 32-40 sensors on one readout line [8]. Increasing the size of microcalorimeter arrays above the kilopixel scale, required to match the throughput of germanium detectors, requires the development of a new readout technology with a much higher multiplexing factor.

  1. Nanophotonic modal dichroism: mode-multiplexed modulators.

    Science.gov (United States)

    Das, Susobhan; Fardad, Shima; Kim, Inki; Rho, Junsuk; Hui, Rongqing; Salandrino, Alessandro

    2016-09-15

    As the diffraction limit is approached, device miniaturization to integrate more functionality per area becomes more and more challenging. Here we propose a strategy to increase the functionality-per-area by exploiting the modal properties of a waveguide system. With such an approach the design of a mode-multiplexed nanophotonic modulator relying on the mode-selective absorption of a patterned indium-tin-oxide (ITO) is proposed. Full-wave simulations of a device operating at the telecom wavelength of 1550 nm show that two modes can be independently modulated, while maintaining performances in line with conventional single-mode ITO modulators reported in the recent literature. The proposed design principles can pave the way to a class of mode-multiplexed compact photonic devices able to effectively multiply the functionality-per-area in integrated photonic systems.

  2. Recent progress on arrayed-waveguide grating wavelength multiplexer

    Science.gov (United States)

    Hida, Yasuhiro

    2004-10-01

    An arrayed-waveguide grating (AWG) is an attractive device for use in a WDM network because it offers multi-channel operation, design flexibility and suitability for mass production. AWGs fabricated using silica-based planar lightwave circuit (PLC) technologies are excellent in terms of loss and long-term stability, and so are widely used in commercial DWDM systems. This paper reviews recent progress on the AWG as regards improving its performance, especially with a view to eliminating polarization sensitivity. It also describes large-scale and compact AWGs formed using high-index contrast waveguides and fiber-connection methods using spot size converters. The second half of the paper reviews recent studies on functional devices incorporating thermo-optic (TO) switches and variable optical attenuators (VOAs).

  3. 1.25-3.125 Gb/s per user PON with RSOA as phase modulator for statistical wavelength ONU

    Science.gov (United States)

    Chu, Guang Yong; Polo, Victor; Lerín, Adolfo; Tabares, Jeison; Cano, Iván N.; Prat, Josep

    2015-12-01

    We report a new scheme to support, cost efficiently, ultra-dense wavelength division multiplexing (UDWDM) for optical access networks. As validating experiment, we apply phase modulation of a reflective semiconductor optical amplifier (RSOA) at the ONU with a single DFB, and simplified coherent receiver at OLT for upstream. We extend the limited 3-dB modulation bandwidth of available uncooled To-can packaged RSOA (~400 MHz) and operate it at 3.125 Gb/s with the optimal performance for phase modulation using small and large signal measurement characteristics. The optimal condition is selected at input power of 0 dBm, with 70 mA bias condition. The sensitivities at 3.125 Gb/s (at BER=10-3) for heterodyne and intradyne detection reach -34.3 dBm and -38.8 dBm, respectively.

  4. Dynamic sensor interrogation using wavelength-swept laser with a polygon-scanner-based wavelength filter.

    Science.gov (United States)

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-07-29

    We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.

  5. Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

    Directory of Open Access Journals (Sweden)

    Kyung Hyun Park

    2013-07-01

    Full Text Available We report a high-speed (~2 kHz dynamic multiplexed fiber Bragg grating (FBG sensor interrogation using a wavelength-swept laser (WSL with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.

  6. Functional Multiplex PageRank

    CERN Document Server

    Iacovacci, Jacopo; Arenas, Alex; Bianconi, Ginestra

    2016-01-01

    Recently it has been recognized that many complex social, technological and biological networks have a multilayer nature and can be described by multiplex networks. Multiplex networks are formed by a set of nodes connected by links having different connotations forming the different layers of the multiplex. Characterizing the centrality of the nodes in a multiplex network is a challenging task since the centrality of the node naturally depends on the importance associated to links of a certain type. Here we propose to assign to each node of a multiplex network a centrality called Functional Multiplex PageRank that is a function of the weights given to every different pattern of connections (multilinks) existent in the multiplex network between any two nodes. Since multilinks distinguish all the possible ways in which the links in different layers can overlap, the Functional Multiplex PageRank can describe important non-linear effects when large relevance or small relevance is assigned to multilinks with overl...

  7. Interfering Heralded Single Photons from Two Separate Silicon Nanowires Pumped at Different Wavelengths

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2016-08-01

    Full Text Available Practical quantum photonic applications require on-demand single photon sources. As one possible solution, active temporal and wavelength multiplexing has been proposed to build an on-demand single photon source. In this scheme, heralded single photons are generated from different pump wavelengths in many temporal modes. However, the indistinguishability of these heralded single photons has not yet been experimentally confirmed. In this work, we achieve 88% ± 8% Hong–Ou–Mandel quantum interference visibility from heralded single photons generated from two separate silicon nanowires pumped at different wavelengths. This demonstrates that active temporal and wavelength multiplexing could generate indistinguishable heralded single photons.

  8. Navigation Using Orthogonal Frequency Division Multiplexed Signals of Opportunity

    Science.gov (United States)

    2007-09-01

    x List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii List of Abbreviations...Correlation Results . . . . . . . . . . . . . . . 48 4.7. Feature (AVERAGE SYMBOL PHASE) Correlation Results . 49 x Figure Page 4.8. Feature (RMS...communica- tions due the complex computations involved with multicarrier modulation/ demod - 16 (a) 64-QAM (b) 16-QAM (c) 4-QAM / QPSK (d) BPSK Figure

  9. 基于多输入多输出-正交频分复用系统的动态马尔可夫链蒙特卡罗检测算法%Dynamic Markov Chain Monte Carlo Detection Based on Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing Systems

    Institute of Scientific and Technical Information of China (English)

    杨辉联; 杨建国; 石海

    2011-01-01

    在多输入多输出-正交频分复用系统中,基于马尔可夫链蒙特卡罗方法的贝叶斯多用户检测算法可以有效地抑制多径衰落、载波频偏以及相位噪声干扰,但因收敛速度较慢导致实时性较差.针对这一问题,提出一种动态马尔可夫链蒙特卡罗检测算法.该算法利用系统状态样本间的相关性和所设定的收敛阈值门限,实现动态选取系统状态采样值的迭代收敛区间,以求在确保算法检测性能的同时,进一步提高检测估计运算的实时性.仿真结果表明,该算法具有收敛速度快、误码率低等优点.%In multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, the Bayesian multiuser detection scheme based on the Markov chain Monte Carlo (MCMC) method has good performance in suppressing multipath fading, carrier frequency offset and phase noise. The algorithm, however, cannot find its application in real-time due to a low convergence rate. To solve this problem, we propose a new method called dynamic MCMC detection. Correlation between samples of the system state and the threshold decided on convergence are used to dynamically select the convergence region about the samples of the system state in an iterative operation. This improves capability of real time operations and maintains the performance of the algorithm. Simulation results show that the proposed method has a higher convergence rate and lower bit error rate.

  10. Design of Data Converters for Dual-carrier Orthogonal Frequency-Division Multiplexing Ultra-wideband System%适用于双载波-正交频分复用超宽带系统的数据转换器设计

    Institute of Scientific and Technical Information of China (English)

    夏杰峰; 哈钱钱; 林宇婧; 叶凡; 任俊彦

    2012-01-01

    Dual-carrier orthogonal frequency-division multiplexing (DC-OFDM) is adopted in China as the ultra-wideband (UWB) national standard. Two data converters are designed based on this UWB system standard, including a four-channel 650 MS/s 8 bit current-steering digital-to-analog converter (DAC) and a four- channel 300 MS/s 6 bit folding-and-interpolating analog-to-digital converter (ADC). Both of them are integrated on a printed circuit board (PCB). The DAC has focused on the matching of current sources and its dynamic performance is improved by reducing the voltage swing of the switch transistors. Testing result shows that one sub-DAC can achieve over 52 dB spurious-free dynamic range (SFDR) locating at 68 MHz input. The ADC adopts inter-stage pipelined switches to relax amplifiers' bandwidth, utilizes active interpolators to further mitigate the offset of the comparators and keeps the signal-to-noise-and-distortion ration (SNDR) of sub-ADC over 32 dB in the entire Nyquist band.%国家超宽带(UWB)标准采用了双载波-正交频分复用技术(DC-OFDM),此设计基于该标准的超宽带系统中用数据转换器,包括一个单片集成4通道650 MS/s 8 bit电流舵数模转换器(DAC)和一个单片集成4通道300 MS/s 6 bit折叠内插模数转换器(ADC),在印刷电路板(PCB)上实现集成.DAC设计着重考虑电流源的匹配,并且采用降摆幅电路提高动态性能,当输入频率为68 MHz时,单个子DAC无杂散动态范围(SFDR)可以达到51dB以上;ADC采用级间流水线开关降低放大器建立要求,采用有源内插进一步降低比较器失调影响,单个子ADC信噪失真比(SNDR)在整个奈奎斯特频带内都保持在32 dB以上.

  11. Multiplex editing system

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a multiplex editing system. The system allows multiple editing of nucleic acid sequences such as genomic sequences, such as knockins of genes of interest in a genome, knockouts of genomic sequences and/or allele replacement. Also provided herein are a method...... for editing nucleic acids and a cell comprising a stably integrated endonuclease....

  12. Multiplex PageRank

    CERN Document Server

    Halu, Arda; Pansaraza, Pietro; Bianconi, Ginestra

    2013-01-01

    Many complex systems can be described as multiplex networks in which the same nodes can interact with one another in different layers, thus forming a set of interacting and co-evolving networks. Examples of such multiplex systems are social networks where people are involved in different types of relationships and interact through various forms of communication media. The ranking of nodes in multiplex networks is one of the most pressing and challenging tasks that research on complex networks is currently facing. When pairs of nodes can be connected through multiple links and in multiple layers, the ranking of nodes should necessarily reflect the importance of nodes in one layer as well as their importance in other interdependent layers. In this paper, we draw on the idea of biased random walks to define the Multiplex PageRank centrality measure in which the effects of the interplay between networks on the centrality of nodes are directly taken into account. In particular, depending on the intensity of the in...

  13. Arthrogryposis multiplex congenita

    DEFF Research Database (Denmark)

    Linnet, Karen Markussen; Balslev, Thomas; Møller-Madsen, Bjarne

    2015-01-01

    Arthrogryposis multiplex congenita (AMC) is a sign rather than a diagnosis. It implies contractures in multiple body areas and occurs in 1:3,000-5,000 live births. Primary aetiologies include neuropathic, myopathic, metabolic, end plate and vascular disorder affecting the developing foetus...

  14. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  15. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  16. The Microwave SQUID Multiplexer

    Science.gov (United States)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  17. PERSONNEL DIVISION BECOMES HUMAN RESOURCES DIVISION

    CERN Document Server

    Division des ressources humaines

    2000-01-01

    In the years to come, CERN faces big challenges in the planning and use of human resources. At this moment, Personnel (PE) Division is being reorganised to prepare for new tasks and priorities. In order to accentuate the purposes of the operation, the name of the division has been changed into Human Resources (HR) Division, with effect from 1st January 2000. Human Resources DivisionTel.73222

  18. Color multiplexing using directional holographic gratings and linear polarization

    Energy Technology Data Exchange (ETDEWEB)

    Lugo, L I; Rodriguez, A; Ramirez, G; Guel, S; Nunez, O F, E-mail: roca@cactus.iico.uaslp.mx [Instituto de Investigacion en Comunicacion Optica (IICO) Universidad Autonoma de San Luis Potosi, S.L.P. (UASLP) (Mexico)

    2011-01-01

    We propose a system of multiplexing and de-multiplexing, which uses a holographic diffraction grating to compel modulated light of different colors to be sent through an optical fiber. Diffraction gratings were fabricated specifically to pick the desired direction in which we wanted the light of different wavelengths to impinge the optic fiber, and also to be separated at the output. It was been found that the system preserves the polarization of light, which give us a one more freedom degree, allowing us to process twice the original information amount.

  19. A pulsated weak-resonant-cavity laser diode with transient wavelength scanning and tracking for injection-locked RZ transmission.

    Science.gov (United States)

    Lin, Gong-Ru; Chi, Yu-Chieh; Liao, Yu-Sheng; Kuo, Hao-Chung; Liao, Zhi-Wang; Wang, Hai-Lin; Lin, Gong-Cheng

    2012-06-18

    By spectrally slicing a single longitudinal-mode from a master weak-resonant-cavity Fabry-Perot laser diode with transient wavelength scanning and tracking functions, the broadened self-injection-locking of a slave weak-resonant-cavity Fabry-Perot laser diode is demonstrated to achieve bi-directional transmission in a 200-GHz array-waveguide-grating channelized dense-wavelength-division-multiplexing passive optical network system. Both the down- and up-stream slave weak-resonant-cavity Fabry-Perot laser diodes are non-return-to-zero modulated below threshold and coherently injection-locked to deliver the pulsed carrier for 25-km bi-directional 2.5 Gbits/s return-to-zero transmission. The master weak-resonant-cavity Fabry-Perot laser diode is gain-switched at near threshold condition and delivers an optical coherent pulse-train with its mode linewidth broadened from 0.2 to 0.8 nm by transient wavelength scanning, which facilitates the broadband injection-locking of the slave weak-resonant-cavity Fabry-Perot laser diodes with a threshold current reducing by 10 mA. Such a transient wavelength scanning induced spectral broadening greatly releases the limitation on wavelength injection-locking range required for the slave weak-resonant-cavity Fabry-Perot laser diode. The theoretical modeling and numerical simulation on the wavelength scanning and tracking effects of the master and slave weak-resonant-cavity Fabry-Perot laser diodes are performed. The receiving power sensitivity for back-to-back transmission at bit-error-rate transmission is less than 2 dB for all 16 channels.

  20. Extracting information from multiplex networks.

    Science.gov (United States)

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ̃(S) for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

  1. Extracting information from multiplex networks

    Science.gov (United States)

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ ˜ S for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

  2. Adaptive gain, equalization, and wavelength stabilization techniques for silicon photonic microring resonator-based optical receivers

    Science.gov (United States)

    Palermo, Samuel; Chiang, Patrick; Yu, Kunzhi; Bai, Rui; Li, Cheng; Chen, Chin-Hui; Fiorentino, Marco; Beausoleil, Ray; Li, Hao; Shafik, Ayman; Titriku, Alex

    2016-03-01

    Interconnect architectures based on high-Q silicon photonic microring resonator devices offer a promising solution to address the dramatic increase in datacenter I/O bandwidth demands due to their ability to realize wavelength-division multiplexing (WDM) in a compact and energy efficient manner. However, challenges exist in realizing efficient receivers for these systems due to varying per-channel link budgets, sensitivity requirements, and ring resonance wavelength shifts. This paper reports on adaptive optical receiver design techniques which address these issues and have been demonstrated in two hybrid-integrated prototypes based on microring drop filters and waveguide photodetectors implemented in a 130nm SOI process and high-speed optical front-ends designed in 65nm CMOS. A 10Gb/s powerscalable architecture employs supply voltage scaling of a three inverter-stage transimpedance amplifier (TIA) that is adapted with an eye-monitor control loop to yield the necessary sensitivity for a given channel. As reduction of TIA input-referred noise is more critical at higher data rates, a 25Gb/s design utilizes a large input-stage feedback resistor TIA cascaded with a continuous-time linear equalizer (CTLE) that compensates for the increased input pole. When tested with a waveguide Ge PD with 0.45A/W responsivity, this topology achieves 25Gb/s operation with -8.2dBm sensitivity at a BER=10-12. In order to address microring drop filters sensitivity to fabrication tolerances and thermal variations, efficient wavelength-stabilization control loops are necessary. A peak-power-based monitoring loop which locks the drop filter to the input wavelength, while achieving compatibility with the high-speed TIA offset-correction feedback loop is implemented with a 0.7nm tuning range at 43μW/GHz efficiency.

  3. Mathematical Verification for Transmission Performance of Centralized Lightwave WDM-RoF-PON with Quintuple Services Integrated in Each Wavelength Channel

    Directory of Open Access Journals (Sweden)

    Shuai Chen

    2015-01-01

    Full Text Available Wavelength-division-multiplexing passive-optical-network (WDM-PON has been recognized as a promising solution of the “last mile” access as well as multibroadband data services access for end users, and WDM-RoF-PON, which employs radio-over-fiber (RoF technique in WDM-PON, is even a more attractive approach for future broadband fiber and wireless access for its strong availability of centralized multiservices transmission operation and its transparency for bandwidth and signal modulation formats. As for multiservices development in WDM-RoF-PON, various system designs have been reported and verified via simulation or experiment till now, and the scheme with multiservices transmitted in each single wavelength channel is believed as the one that has the highest bandwidth efficiency; however, the corresponding mathematical verification is still hard to be found in state-of-the-art literature. In this paper, system design and data transmission performance of a quintuple services integrated WDM-RoF-PON which jointly employs carrier multiplexing and orthogonal modulation techniques, have been theoretically analyzed and verified in detail; moreover, the system design has been duplicated and verified experimentally and the theory system of such WDM-RoF-PON scheme has thus been formed.

  4. Tunable multi-wavelength thulium-doped fiber laser incorporating two-stage cascaded Sagnac loop comb filter

    Science.gov (United States)

    Zhu, Lianqing; He, Wei; Dong, Mingli; Lou, Xiaoping; Luo, Fei

    2016-08-01

    A tunable multi-wavelength narrow-linewidth thulium-doped fiber laser employing two-stage cascaded Sagnac loop mirrors is proposed and experimentally demonstrated. The designed fiber laser is composed of a pump source, wavelength division multiplex, circulator, thulium-doped fiber, polarization controllers (PCs), couplers and polarization-maintaining fibers (PMFs). Two cascaded Sagnac loops are used as the cavity reflector and filter, and the proposed filter is fabricated using two sections of PMFs with 2-m and 1-m lengths, respectively. In the experiment, the laser threshold is 110 mW, and laser can emit single, double, triple, quadruple and quintuple wavelengths in the spectral range of 1873-1901 nm through the simultaneous adjustment of the two PCs. The power fluctuations and 3-dB linewidth are less than 2.1 dB and 0.2 nm, respectively, over 10 min at room temperature, and the side-mode suppression ratio is greater than 20 dB. The proposed laser will be useful in various fields, such as spectral analysis, fiber sensing and optical communication.

  5. Multiplexing oscillatory biochemical signals.

    Science.gov (United States)

    de Ronde, Wiet; ten Wolde, Pieter Rein

    2014-04-01

    In recent years it has been increasingly recognized that biochemical signals are not necessarily constant in time and that the temporal dynamics of a signal can be the information carrier. Moreover, it is now well established that the protein signaling network of living cells has a bow-tie structure and that components are often shared between different signaling pathways. Here we show by mathematical modeling that living cells can multiplex a constant and an oscillatory signal: they can transmit these two signals simultaneously through a common signaling pathway, and yet respond to them specifically and reliably. We find that information transmission is reduced not only by noise arising from the intrinsic stochasticity of biochemical reactions, but also by crosstalk between the different channels. Yet, under biologically relevant conditions more than 2 bits of information can be transmitted per channel, even when the two signals are transmitted simultaneously. These observations suggest that oscillatory signals are ideal for multiplexing signals.

  6. Experimental validation of concept for real-time wavelength monitoring and tracking in densely populated WDM networks

    Science.gov (United States)

    Vukovic, Alex; Savoie, Michel; Hua, Heng; Campbell, Scott; Nguyen, Thao

    2005-10-01

    As the telecom industry responds with technological innovations to requests for higher data rates, increased number of wavelengths at higher densities, longer transmission distances and more intelligence for next generation optical networks, new monitoring schemes based on monitoring and tracking of each wavelength need to be developed and deployed. An optical layer monitoring scheme, based on tracking key optical parameters per each wavelength, is considered to be one of enablers for the transformation of today's opaque networks to dynamic, agile future networks. Ever-tighter network monitoring and control will be required to fulfill customer Service Level Agreements (SLAs). A wavelength monitoring and tracking concept was developed as a three-step approach. It started with the identification of all critical parameters required to obtain sufficient information about each wavelength; followed by the deployment of a cost-efficient device to provide simultaneous, accurate measurements in real-time of all critical parameters; and finally, the formulation of a specification for wavelength monitoring and tracking devices for real-time, simultaneous measurements and processing the data. A prototype solution based on a commercially available integrated modular spectrometer within a testbed environment associated with the all-optical network (AON) demonstrator program was used to verify and validate the wavelength monitoring and tracking concept. The developed concept verified that it can manage tracking of 32 wavelengths within a wavelength division multiplexing network. The developed concept presented in this paper can be used inside the transparent domains of networks to detect, identify and locate signal degradations in real-time, even sometimes to recognize the cause of the failure. Aside from the reduction of operational expenses due to the elimination of the need for operators at every site and skilled field technicians to isolate and repair faults, the developed

  7. Wavelength tunable distributed Bragg reflector laser integrated with electro-absorption modulator by a combined method of selective area growth and quantum well intermixing

    Science.gov (United States)

    Zhao, Ling-Juan; Zhang, Jing; Wang, Lu; Cheng, Yuan-Bing; Pan, Jiao-Qing; Liu, Hong-Bo; Zhu, Hon-Liang; Zhou, Fan; Bian, Jing; Wang, Bao-Jun; Zhu, Ning-Hua; Wang, Wei

    2008-03-01

    Wavelength tunable electro-absorption modulated distributed Bragg reflector lasers (TEMLs) are promising light source in dense wavelength division multiplexing (DWDM) optical fiber communication system due to high modulation speed, small chirp, low drive voltage, compactness and fast wavelength tuning ability. Thus, increased the transmission capacity, the functionality and the flexibility are provided. Materials with bandgap difference as large as 250nm have been integrated on the same wafer by a combined technique of selective area growth (SAG) and quantum well intermixing (QWI), which supplies a flexible and controllable platform for the need of photonic integrated circuits (PIC). A TEML has been fabricated by this technique for the first time. The component has superior characteristics as following: threshold current of 37mA, output power of 3.5mW at 100mA injection and 0V modulator bias voltage, extinction ratio of more than 20 dB with modulator reverse voltage from 0V to 2V when coupled into a single mode fiber, and wavelength tuning range of 4.4nm covering 6 100-GHz WDM channels. A clearly open eye diagram is observed when the integrated EAM is driven with a 10-Gb/s electrical NRZ signal. A good transmission characteristic is exhibited with power penalties less than 2.2 dB at a bit error ratio (BER) of 10 -10 after 44.4 km standard fiber transmission.

  8. On-chip all-optical wavelength conversion of multicarrier, multilevel modulation (OFDM m-QAM) signals using a silicon waveguide.

    Science.gov (United States)

    Li, Chao; Gui, Chengcheng; Xiao, Xi; Yang, Qi; Yu, Shaohua; Wang, Jian

    2014-08-01

    We report on-chip all-optical wavelength conversion of multicarrier multilevel modulation signals in a silicon waveguide. Using orthogonal frequency-division multiplexing (OFDM) combined with advanced multilevel quadrature amplitude modulation (QAM) signals (i.e., OFDM m-QAM), we experimentally demonstrate all-optical wavelength conversions of 3.2 Gbaud/s OFDM 16/32/64/128-QAM signals based on the degenerate four-wave mixing (FWM) nonlinear effect in a silicon waveguide. The measured optical signal-to-noise ratio (OSNR) penalties of wavelength conversion are ∼3  dB for OFDM 16-QAM and ∼4  dB for OFDM 32-QAM at 7% forward error correction (FEC) threshold and ∼3.5  dB for OFDM 64-QAM and ∼4.5  dB for OFDM 128-QAM at 20% FEC threshold. The observed clear constellations of converted idlers imply favorable performance obtained for silicon-waveguide-based OFDM 16/32/64/128-QAM wavelength conversions.

  9. Extracting Information from Multiplex Networks

    CERN Document Server

    Iacovacci, Jacopo

    2016-01-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from Big Data. For these reasons characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function $\\widetilde{\\Theta}^{S}$ for describing their mesoscale organization and community structure. As working examples for studying thes...

  10. Clustering Coefficients in Multiplex Networks

    CERN Document Server

    Cozzo, Emanuele; De Domenico, Manlio; Solé, Albert; Arenas, Alex; Gómez, Sergio; Porter, Mason A; Moreno, Yamir

    2013-01-01

    Recent advances in the study of complex networked systems has highlighted that our interconnected world is made of networks that are coupled together through different layers that each stand for one type of interaction or system. Despite this situation, it is traditional to aggregate multiplex data into a single weighted network in order take advantage of existing tools. This is admittedly convenient, but it is also extremely problematic. In this paper, we generalize the concept of clustering coefficients for multiplex networks. We show how the layered structure of multiplex networks introduces a new degree of freedom that has a fundamental effect on transitivity. We compute our new multiplex clustering coefficients for several real multiplex networks and illustrate why generalizing monoplex concepts to multiplex networks must be done with great care.

  11. The Astrophysics Science Division Annual Report 2008

    Science.gov (United States)

    Oegerle, William; Reddy, Francis; Tyler, Pat

    2009-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. This report includes the Division's activities during 2008.

  12. Coupled metal gap waveguides as plasmonic wavelength sorters.

    Science.gov (United States)

    Kang, Zhiwen; Wang, Guo Ping

    2008-05-26

    We propose a coupled metal gap waveguide structure for realizing plasmonic wavelength sorters. Theoretical analysis from the coupled-wave theory reveals that wavelength dependent coupling length of guided surface plasmon polaritons contributes to the routing of different wavelengths to different output ports with reasonable high extinction ratio. The analytical results are confirmed by the finite-difference time-domain numerical simulations. Our result may provide an alternative way to construct nanoscale frequency multiplexers, routers, and sorters for nanophotonic integration and optical communication.

  13. Wavelength-Dependence of Inter-Core Crosstalk in Homogeneous Multi-Core Fibers

    DEFF Research Database (Denmark)

    Ye, Feihong; Saitoh, Kunimasa; Takenaga, Katsuhiro;

    2016-01-01

    The wavelength dependence of inter-core crosstalk in homogeneous multi-core fibers (MCFs) is investigated, and the corresponding analytical expressions are derived. The derived analytical expressions can be used to determine the crosstalk at any wavelength necessary for designing future MCF...... wavelengthdivision multiplexing (MCF-WDM) networks and transmission systems....

  14. Functional Multiplex PageRank

    Science.gov (United States)

    Iacovacci, Jacopo; Rahmede, Christoph; Arenas, Alex; Bianconi, Ginestra

    2016-10-01

    Recently it has been recognized that many complex social, technological and biological networks have a multilayer nature and can be described by multiplex networks. Multiplex networks are formed by a set of nodes connected by links having different connotations forming the different layers of the multiplex. Characterizing the centrality of the nodes in a multiplex network is a challenging task since the centrality of the node naturally depends on the importance associated to links of a certain type. Here we propose to assign to each node of a multiplex network a centrality called Functional Multiplex PageRank that is a function of the weights given to every different pattern of connections (multilinks) existent in the multiplex network between any two nodes. Since multilinks distinguish all the possible ways in which the links in different layers can overlap, the Functional Multiplex PageRank can describe important non-linear effects when large relevance or small relevance is assigned to multilinks with overlap. Here we apply the Functional Page Rank to the multiplex airport networks, to the neuronal network of the nematode C. elegans, and to social collaboration and citation networks between scientists. This analysis reveals important differences existing between the most central nodes of these networks, and the correlations between their so-called pattern to success.

  15. All-Optical Regenerative OTDM Add-Drop Multiplexing at 40 Gb/s using Monolithic InP Mach-Zehnder Interferometer

    DEFF Research Database (Denmark)

    Fischer, St.; Dülk, M.; Gamper, E.;

    2000-01-01

    We present a novel method for all-optical add-drop multiplexing having regenerative capability for 40-Gb/s optical time-division multiplexed (OTDM) data using a semiconductor optical amplifier (SOA) based, monolithic Mach-Zehnder interferometer (MZI). Simultaneous dropping of one 10-Gb/s channel ...

  16. Optical Wavelet Signals Processing and Multiplexing

    Science.gov (United States)

    Cincotti, Gabriella; Moreolo, Michela Svaluto; Neri, Alessandro

    2005-12-01

    We present compact integrable architectures to perform the discrete wavelet transform (DWT) and the wavelet packet (WP) decomposition of an optical digital signal, and we show that the combined use of planar lightwave circuits (PLC) technology and multiresolution analysis (MRA) can add flexibility to current multiple access optical networks. We furnish the design guidelines to synthesize wavelet filters as two-port lattice-form planar devices, and we give some examples of optical signal denoising and compression/decompression techniques in the wavelet domain. Finally, we present a fully optical wavelet packet division multiplexing (WPDM) scheme where data signals are waveform-coded onto wavelet atom functions for transmission, and numerically evaluate its performances.

  17. Implementing Statistical Multiplexing in DVB-H

    Directory of Open Access Journals (Sweden)

    Mehdi Rezaei

    2009-01-01

    Full Text Available A novel technique for implementing statistical multiplexing (StatMux of broadcast services over Digital Video Broadcasting for Handhelds (DVB-H channels is proposed. DVB-H uses a time-sliced transmission scheme to reduce the power consumption used for radio reception part in DVB-H receivers. Due to the time-sliced transmission scheme, the implementation of known StatMux methods for DVB-H application presents some challenges which are addressed in this paper. The proposed StatMux technique is implemented in conjunction with the time-slicing transmission scheme. The combination is similar to a time division multiplexing (TDM scheme. The proposed StatMux method considerably decreases the end-to-end delay of DVB-H services while it maximizes the usage of available bandwidth. Moreover, the proposed method can effectively decrease the channel switching delay of DVB-H services. Simulation results show a high performance for the proposed StatMux method.

  18. Performance of Thin-Film as Wavelength Filter in Wdm-Pof Network

    Directory of Open Access Journals (Sweden)

    Mohd S.A. Rahman

    2012-01-01

    Full Text Available Problem statement: Huge capacity for data transmission and bandwidth are becoming a need nowadays. High cost of implementation using optical fibers prevents utilization of the technology as wide as possible. Approach: Wavelength Division Multiplexing (WDM was a technique that offers the solution for providing better bandwidth. WDM technique allows several signals that have different wavelengths to be transmitted in a single optical fiber to the receiver without any external interference or internal interruption between the signals transmitted simultaneously. WDM technique requires splitting of signals at reaching the receivers and one of the solutions presented in this study will provide a method using inexpensive filtering device that functions efficiently as a demultiplexer that can be develop without any complication. There were a lot of systems that provided demultiplexing techniques in the industry; all the systems are expensive to be implemented. Here the study provides an effective and easy to construct demultiplexer by using colored thin films. The WDM-POF system studies the performances of thin-films to be used as demultiplexer and red thin-films will be focused. Results: In theory, the thin-films will filter out any undesired signals that pass through the fiber and the desired signal will be carried to the end-receiver. The effectiveness of each red thin- films were characterized by analyzing the insertion losses (dBm and power output (µW. Characterization analysis in this study includes the characterization test of using the same sources towards different types of red thin-films to obtain the best film that could filter out any undesired wavelength and let only the desired wavelength to be transmitted at high percentage. An initial stage of selecting different colored films by analyzing the energy spectrum distribution curves for the potential red thin- films will then be characterized where red, blue and green LED sources were

  19. Simulation of path delay multiplexing-based Fourier transform spectrometer for fiber Bragg grating interrogation.

    Science.gov (United States)

    Chelliah, Pandian; Sahoo, Trilochan; Singh, Sheela; Sujatha, Annie

    2015-10-20

    A Fourier transform spectrometer (FTS) used for interrogating a fiber Bragg grating (FBG) consists of a scanning-type interferometer. The FTS has a broad wavelength range of operation and good multiplexing capability. However, it has poor wavelength resolution and interrogation speed. We propose a modification to the FTS using path delay multiplexing to improve the same. Using this method, spatial resolution and interrogation time can be improved by n times by using n path delays. In this paper, simulation results for n=2, 5 are shown.

  20. 1 λ × 1.44 Tb/s free-space IM-DD transmission employing OAM multiplexing and PDM.

    Science.gov (United States)

    Zhu, Yixiao; Zou, Kaiheng; Zheng, Zhennan; Zhang, Fan

    2016-02-22

    We report the experimental demonstration of single wavelength terabit free-space intensity modulation direct detection (IM-DD) system employing both orbital angular momentum (OAM) multiplexing and polarization division multiplexing (PDM). In our experiment, 12 OAM modes with two orthogonal polarization states are used to generate 24 channels for transmission. Each channel carries 30 Gbaud Nyquist PAM-4 signal. Therefore an aggregate gross capacity record of 1.44 Tb/s (12 × 2 × 30 × 2 Gb/s) is acheived with a modulation efficiency of 48 bits/symbol. After 0.8m free-space transmission, the bit error rates (BERs) of all the channels are below the 20% hard-decision forward error correction (HD-FEC) threshold of 1.5 × 10(-2). After applying the decision directed recursive least square (DD-RLS) based filter and post filter, the BERs of two polarizations can be reduced from 5.3 × 10(-3) and 7.3 × 10(-3) to 2.2 × 10(-3) and 3.4 × 10(-3), respectively.

  1. Design of Joint Spatial and Power Domain Multiplexing Scheme for Massive MIMO Systems

    Directory of Open Access Journals (Sweden)

    Zheng Jiang

    2015-01-01

    Full Text Available Massive Multiple-Input Multiple-Output (MIMO is one of the key techniques in 5th generation wireless systems (5G due to its potential ability to improve spectral efficiency. Most of the existing works on massive MIMO only consider Time Division Duplex (TDD operation that relies on channel reciprocity between uplink and downlink channels. For Frequency Division Duplex (FDD systems, with continued efforts, some downlink multiuser MIMO scheme was recently proposed in order to enable “massive MIMO” gains and simplified system operations with limited number of radio frequency (RF chains in FDD system. However these schemes, such as Joint Spatial Division and Multiplexing (JSDM scheme and hybrid precoding scheme, only focus on multiuser transmission in spatial domain. Different from most of the existing works, this paper proposes Joint Spatial and Power Multiplexing (JSPM scheme in FDD systems. It extends existing FDD schemes from spatial division and multiplexing to joint spatial and power domain to achieve more multiplexing gain. The user grouping and scheduling scheme of JSPM is studied and the asymptotic expression for the sum capacity is derived as well. Finally, simulations are conducted to illustrate the effectiveness of the proposed scheme.

  2. Impulse Response of a 36-Core Few-Mode Photonic Lantern Hybrid Spatial-Multiplexer

    DEFF Research Database (Denmark)

    Rommel, Simon; Mendinueta, José Manuel Delgado; Klaus, Werner

    2017-01-01

    Space division multiplexing (SDM) using fibers with multiple cores and/or supporting multiple modes has become an essential technology to support Pbit/s transmissions in a single fiber [1,2]. Despite significant mode-mixing in few-mode fibers (FMF), the original signals can be recovered through...

  3. Multiplexed operation of a micromachined ultrasonic droplet ejector array.

    Science.gov (United States)

    Forbes, Thomas P; Degertekin, F Levent; Fedorov, Andrei G

    2007-10-01

    A dual-sample ultrasonic droplet ejector array is developed for use as a soft-ionization ion source for multiplexed mass spectrometry (MS). Such a multiplexed ion source aims to reduce MS analysis time for multiple analyte streams, as well as allow for the synchronized ejection of the sample(s) and an internal standard for quantitative results and mass calibration. Multiplexing is achieved at the device level by division of the fluid reservoir and separating the active electrodes of the piezoelectric transducer for isolated application of ultrasonic wave energy to each domain. The transducer is mechanically shaped to further reduce the acoustical crosstalk between the domains. Device design is performed using finite-element analysis simulations and supported by experimental characterization. Isolated ejection of approximately 5 microm diameter water droplets from individual domains in the micromachined droplet ejector array at around 1 MHz frequency is demonstrated by experiments. The proof-of-concept demonstration using a dual-sample device also shows potential for multiplexing with larger numbers of analytes.

  4. Experimental demonstration of 110-Gb/s unsynchronized band-multiplexed superchannel coherent optical OFDM/OQAM system.

    Science.gov (United States)

    Li, Zhaohui; Jiang, Tao; Li, Haibo; Zhang, Xuebing; Li, Cai; Li, Chao; Hu, Rong; Luo, Ming; Zhang, Xu; Xiao, Xiao; Yang, Qi; Yu, Shaohua

    2013-09-23

    In this paper, we experimentally demonstrate the first 110-Gb/s multi-band superchannel coherent optical orthogonal frequency-division multiplexing based on offset quadrature amplitude modulation (OFDM/OQAM) system. Unlike the conventional orthogonal band-multiplexed OFDM system, no timing or frequency synchronization is required for the OFDM/OQAM system. We further investigate the influence of guard band, and find that very trivial guard band spacing (OFDM system.

  5. Portable Multiplex Pathogen Detector

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S; McBride, M T; Matthews, D; Rao, R

    2002-07-15

    Tumor marker concentrations in serum provide useful information regarding clinical stage and prognosis of cancer and can thus be used for presymptomatic diagnostic purposes. Currently, detection and identification of soluble analytes in biological fluids is conducted by methods including bioassays, ELISA, PCR, DNA chip or strip tests. While these technologies are generally sensitive and specific, they are time consuming, labor intensive and cannot be multiplexed. Our goal is to develop a simple, point-of-care, portable, liquid array-based immunoassay device capable of simultaneous detection of a variety of cancer markers. Here we describe the development of assays for the detection of Serum Prostate Specific Antigen, and Ovalbumin from a single sample. The multiplexed immunoassays utilize polystyrene microbeads. The beads are imbedded with precise ratios of red and orange fluorescent dyes yielding an array of 100 beads, each with a unique spectral address (Figure 1). Each bead can be coated with capture antibodies specific for a given antigen. After antigen capture, secondary antibodies sandwich the bound antigen and are indirectly labeled by the fluorescent reporter phycoerythrin (PE). Each optically encoded and fluorescently-labeled microbead is then individually interrogated. A red laser excites the dye molecules imbedded inside the bead and classifies the bead to its unique bead set, and a green laser quantifies the assay at the bead surface. This technology has been proven to be comparable to the ELISA in terms of sensitivity and specificity. We also describe the laser-based instrumentation used to acquire fluorescent bead images Following the assay, droplets of bead suspension containing a mixture of bead classes were deposited onto filters held in place by a disposable plexiglass device and the resultant arrays viewed under the fluorescent imaging setup. Using the appropriate filter sets to extract the necessary red, orange and green fluorescence from the

  6. Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Edward Daykin

    2012-05-24

    This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.

  7. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Piat, M.; Decourcelle, T.; Perbost, C.; Chapron, C.; Rambaud, D.; Maestre, S.; Marty, W.; Montier, L.

    2016-07-01

    A cryogenic 128:1 Time-Domain Multiplexer (TDM) has been developed for the readout of kilo-pixel Transition Edge Sensor (TES) arrays dedicated to the Q&U Bolometric Interferometer for Cosmology (QUBIC) instrument which aims to measure the B-mode polarization of the Cosmic Microwave Background. Superconducting QUantum Interference Devices (SQUIDs) are usually used to read out TESs. Moreover, SQUIDs are used to build TDM by biasing sequentially the SQUIDs connected together—one for each TES. In addition to this common technique which allows a typical 32 multiplexing factor, a cryogenic integrated circuit provides a 4:1 second multiplexing stage. This cryogenic integrated circuit is one of the original part of our TDM achieving an unprecedented 128 multiplexing factor. We present these two dimension TDM stages: topology of the SQUID multiplexer, operation of the cryogenic integrated circuit, and integration of the full system to read out a TES array dedicated to the QUBIC instrument. Flux-locked loop operation in multiplexed mode is also discussed.

  8. Percolation in real multiplex networks

    CERN Document Server

    Bianconi, Ginestra

    2016-01-01

    We present an exact mathematical framework able to describe site-percolation transitions in real multiplex networks. Specifically, we consider the average percolation diagram valid over an infinite number of random configurations where nodes are present in the system with given probability. The approach relies on the locally treelike ansatz, so that it is expected to accurately reproduce the true percolation diagram of sparse multiplex networks with negligible number of short loops. The performance of our theory is tested in social, biological, and transportation multiplex graphs. When compared against previously introduced methods, we observe improvements in the prediction of the percolation diagrams in all networks analyzed. Results from our method confirm previous claims about the robustness of real multiplex networks, in the sense that the average connectedness of the system does not exhibit any significant abrupt change as its individual components are randomly destroyed.

  9. Percolation in real multiplex networks

    Science.gov (United States)

    Bianconi, Ginestra; Radicchi, Filippo

    2016-12-01

    We present an exact mathematical framework able to describe site-percolation transitions in real multiplex networks. Specifically, we consider the average percolation diagram valid over an infinite number of random configurations where nodes are present in the system with given probability. The approach relies on the locally treelike ansatz, so that it is expected to accurately reproduce the true percolation diagram of sparse multiplex networks with negligible number of short loops. The performance of our theory is tested in social, biological, and transportation multiplex graphs. When compared against previously introduced methods, we observe improvements in the prediction of the percolation diagrams in all networks analyzed. Results from our method confirm previous claims about the robustness of real multiplex networks, in the sense that the average connectedness of the system does not exhibit any significant abrupt change as its individual components are randomly destroyed.

  10. Bond percolation on multiplex networks

    CERN Document Server

    Hackett, A; Gómez, S; Arenas, A; Gleeson, J P

    2015-01-01

    We present an analytical approach for bond percolation on multiplex networks and use it to determine the expected size of the giant connected component and the value of the critical bond occupation probability in these networks. We advocate the relevance of these tools to the modeling of multilayer robustness and contribute to the debate on whether any benefit is to be yielded from studying a full multiplex structure as opposed to its monoplex projection, especially in the seemingly irrelevant case of a bond occupation probability that does not depend on the layer. Although we find that in many cases the predictions of our theory for multiplex networks coincide with previously derived results for monoplex networks, we also uncover the remarkable result that for a certain class of multiplex networks, well described by our theory, new critical phenomena occur as multiple percolation phase transitions are present. We provide an instance of this phenomenon in a multipex network constructed from London rail and Eu...

  11. Multiplexing of spatial modes in the mid-IR region

    Science.gov (United States)

    Gailele, Lucas; Maweza, Loyiso; Dudley, Angela; Ndagano, Bienvenu; Rosales-Guzman, Carmelo; Forbes, Andrew

    2017-02-01

    Traditional optical communication systems optimize multiplexing in polarization and wavelength both trans- mitted in fiber and free-space to attain high bandwidth data communication. Yet despite these technologies, we are expected to reach a bandwidth ceiling in the near future. Communications using orbital angular momentum (OAM) carrying modes offers infinite dimensional states, providing means to increase link capacity by multiplexing spatially overlapping modes in both the azimuthal and radial degrees of freedom. OAM modes are multiplexed and de-multiplexed by the use of spatial light modulators (SLM). Implementation of complex amplitude modulation is employed on laser beams phase and amplitude to generate Laguerre-Gaussian (LG) modes. Modal decomposition is employed to detect these modes due to their orthogonality as they propagate in space. We demonstrate data transfer by sending images as a proof-of concept in a lab-based scheme. We demonstrate the creation and detection of OAM modes in the mid-IR region as a precursor to a mid-IR free-space communication link.

  12. Recent advances in high-capacity free-space optical and radio-frequency communications using orbital angular momentum multiplexing

    Science.gov (United States)

    Willner, Alan E.; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Li, Long; Zhao, Zhe; Wang, Jian; Tur, Moshe; Molisch, Andreas F.; Ashrafi, Solyman

    2017-02-01

    There is a continuing growth in the demand for data bandwidth, and the multiplexing of multiple independent data streams has the potential to provide the needed data capacity. One technique uses the spatial domain of an electromagnetic (EM) wave, and space division multiplexing (SDM) has become increasingly important for increased transmission capacity and spectral efficiency of a communication system. A subset of SDM is mode division multiplexing (MDM), in which multiple orthogonal beams each on a different mode can be multiplexed. A potential modal basis set to achieve MDM is to use orbital angular momentum (OAM) of EM waves. In such a system, multiple OAM beams each carrying an independent data stream are multiplexed at the transmitter, propagate through a common medium and are demultiplexed at the receiver. As a result, the total capacity and spectral efficiency of the communication system can be multiplied by a factor equal to the number of transmitted OAM modes. Over the past few years, progress has been made in understanding the advantages and limitations of using multiplexed OAM beams for communication systems. In this review paper, we highlight recent advances in the use of OAM multiplexing for high-capacity free-space optical and millimetre-wave communications. We discuss different technical challenges (e.g. atmospheric turbulence and crosstalk) as well as potential techniques to mitigate such degrading effects. This article is part of the themed issue 'Optical orbital angular momentum'.

  13. Recent advances in high-capacity free-space optical and radio-frequency communications using orbital angular momentum multiplexing.

    Science.gov (United States)

    Willner, Alan E; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Li, Long; Zhao, Zhe; Wang, Jian; Tur, Moshe; Molisch, Andreas F; Ashrafi, Solyman

    2017-02-28

    There is a continuing growth in the demand for data bandwidth, and the multiplexing of multiple independent data streams has the potential to provide the needed data capacity. One technique uses the spatial domain of an electromagnetic (EM) wave, and space division multiplexing (SDM) has become increasingly important for increased transmission capacity and spectral efficiency of a communication system. A subset of SDM is mode division multiplexing (MDM), in which multiple orthogonal beams each on a different mode can be multiplexed. A potential modal basis set to achieve MDM is to use orbital angular momentum (OAM) of EM waves. In such a system, multiple OAM beams each carrying an independent data stream are multiplexed at the transmitter, propagate through a common medium and are demultiplexed at the receiver. As a result, the total capacity and spectral efficiency of the communication system can be multiplied by a factor equal to the number of transmitted OAM modes. Over the past few years, progress has been made in understanding the advantages and limitations of using multiplexed OAM beams for communication systems. In this review paper, we highlight recent advances in the use of OAM multiplexing for high-capacity free-space optical and millimetre-wave communications. We discuss different technical challenges (e.g. atmospheric turbulence and crosstalk) as well as potential techniques to mitigate such degrading effects.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

  14. Navigability of multiplex temporal network

    Science.gov (United States)

    Wang, Yan; Song, Qiao-Zhen

    2017-01-01

    Real world complex systems have multiple levels of relationships and in many cases, they need to be modeled as multiplex networks where the same nodes can interact with each other in different layers, such as social networks. However, social relationships only appear at prescribed times so the temporal structures of edge activations can also affect the dynamical processes located above them. To consider both factors are simultaneously, we introduce multiplex temporal networks and propose three different walk strategies to investigate the concurrent dynamics of random walks and the temporal structure of multiplex networks. Thus, we derive analytical results for the multiplex centrality and coverage function in multiplex temporal networks. By comparing them with the numerical results, we show how the underlying topology of the layers and the walk strategy affect the efficiency when exploring the networks. In particular, the most interesting result is the emergence of a super-diffusion process, where the time scale of the multiplex is faster than that of both layers acting separately.

  15. Computational Fair Division

    DEFF Research Database (Denmark)

    Branzei, Simina

    Fair division is a fundamental problem in economic theory and one of the oldest questions faced through the history of human society. The high level scenario is that of several participants having to divide a collection of resources such that everyone is satisfied with their allocation -- e.g. two...... heirs dividing a car, house, and piece of land inherited. The literature on fair division was developed in the 20th century in mathematics and economics, but computational work on fair division is still sparse. This thesis can be seen as an excursion in computational fair division divided in two parts...... study alternative and richer models, such as externalities in cake cutting, simultaneous cake cutting, and envy-free cake cutting. The second part of the thesis tackles the fair allocation of multiple goods, divisible and indivisible. In the realm of divisible goods, we investigate the well known...

  16. Wavelength conversion devices

    DEFF Research Database (Denmark)

    Mikkelsen, Benny; Durhuus, Terji; Jørgensen, Carsten

    1996-01-01

    system requirements. The ideal wavelength converter should be transparent to the bit rate and signal format and provide an unchirped output signal with both a high extinction ratio and a large signal-to-noise ratio. It should allow conversion to both shorter and longer wavelengths with equal performance...

  17. Multiplexed lasing in tissues

    Science.gov (United States)

    Chen, Yu-Cheng; Chen, Qiushu; Fan, Xudong

    2017-02-01

    Biolasers are an emerging technology for next generation biochemical detection and clinical applications. Progress has recently been made to achieve lasing from biomolecules and single living cells. Tissues, which consist of cells embedded in extracellular matrix, mimic more closely the actual complex biological environment in a living body and therefore are of more practical significance. Here, we developed a highly versatile tissue laser platform, in which tissues stained with fluorophores are sandwiched in a high-Q Fabry-Pérot microcavity. Distinct lasing emissions from muscle and adipose tissues stained respectively with fluorescein isothiocyanate (FITC) and boron-dipyrromethene (BODIPY), and hybrid muscle/adipose tissue with dual-staining were achieved with a threshold of only 10 μJ/mm2. Additionally, we investigated how tissue structure/geometry, tissue thickness, and staining dye concentration affect the tissue laser. It is further found that, despite large fluorescence spectral overlap between FITC and BODIPY in tissues, their lasing emissions could be clearly distinguished and controlled due to their narrow lasing bands and different lasing thresholds, thus enabling highly multiplexed detection. Our tissue laser platform can be broadly applicable to various types of tissues/diseases. It provides a new tool for a wide range of biological and biomedical applications, such as diagnostics/screening of tissues and identification/monitoring of biological transformations in tissue engineering.

  18. New multiplexing scheme for monitoring fiber optic Bragg grating sensors in the coherence domain

    OpenAIRE

    Dakin, J.P.; Ecke, W.; Rothardt, M.; Schauer, J; Usbeck, K.; Willsch, R.

    1997-01-01

    A new multiplexing scheme for monitoring fiber optic Bragg gratings in the coherence domain has been developed. Grating pairs with different grating distances are distributed along a fiber line, and interference between their reflections is monitored with a scanning Michelson interferometer. The Bragg wavelength of the individual sensor elements is determined from the interference signal frequency

  19. Comparison Study on Three Different Reconfigurable Optical Add Drop Multiplexer Architectures

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin; ZHANG Yang-an; HUANG Yong-qing; REN Xiao-min

    2007-01-01

    In this paper, we present the evolution of reconfigurable optical add drop multiplexer(ROADM) technologies, and compare three main ROADM architectures available on the market today. Three architectures include broadcast-select and demux-switch-mux[and the integrated version planar lightwave circuit(PLC)] and wavelengths-selective switch.

  20. Correlated multiplexity induces unusual connectivity in multiplex random networks

    CERN Document Server

    Lee, Kyu-Min; Cho, Won-kuk; Goh, K -I; Kim, I -M

    2011-01-01

    Nodes in a complex networked system often engage in more than one type of interactions among them; they form a multiplex network with multiple types of links. In real-world complex systems, a node's degree for one type of links and that for the other are not randomly distributed but correlated, which we term correlated multiplexity. In this paper we study a simple model of multiplex random networks and show that the correlated multiplexity can induce unusual properties of giant component in the network. Specifically, when the degrees of a node for different interactions in a duplex Erdos-Renyi network are maximally correlated, the network contains the giant component for any nonzero link densities. On the contrary, when the degrees of a node are maximally anti-correlated, the emergence of giant component is significantly delayed, yet the entire network becomes connected into a single component at a finite link density. We also discuss the mixing patterns and the cases with imperfect correlated multiplexity.

  1. Remote (250 km Fiber Bragg Grating Multiplexing System

    Directory of Open Access Journals (Sweden)

    Manuel Lopez-Amo

    2011-09-01

    Full Text Available We propose and demonstrate two ultra-long range fiber Bragg grating (FBG sensor interrogation systems. In the first approach four FBGs are located 200 km from the monitoring station and a signal to noise ratio of 20 dB is obtained. The second improved version is able to detect the four multiplexed FBGs placed 250 km away, offering a signal to noise ratio of 6–8 dB. Consequently, this last system represents the longest range FBG sensor system reported so far that includes fiber sensor multiplexing capability. Both simple systems are based on a wavelength swept laser to scan the reflection spectra of the FBGs, and they are composed by two identical-lengths optical paths: the first one intended to launch the amplified laser signal by means of Raman amplification and the other one is employed to guide the reflection signal to the reception system.

  2. Efficient exploration of multiplex networks

    Science.gov (United States)

    Battiston, Federico; Nicosia, Vincenzo; Latora, Vito

    2016-04-01

    Efficient techniques to navigate networks with local information are fundamental to sample large-scale online social systems and to retrieve resources in peer-to-peer systems. Biased random walks, i.e. walks whose motion is biased on properties of neighbouring nodes, have been largely exploited to design smart local strategies to explore a network, for instance by constructing maximally mixing trajectories or by allowing an almost uniform sampling of the nodes. Here we introduce and study biased random walks on multiplex networks, graphs where the nodes are related through different types of links organised in distinct and interacting layers, and we provide analytical solutions for their long-time properties, including the stationary occupation probability distribution and the entropy rate. We focus on degree-biased random walks and distinguish between two classes of walks, namely those whose transition probability depends on a number of parameters which is extensive in the number of layers, and those whose motion depends on intrinsically multiplex properties of the neighbouring nodes. We analyse the effect of the structure of the multiplex network on the steady-state behaviour of the walkers, and we find that heterogeneous degree distributions as well as the presence of inter-layer degree correlations and edge overlap determine the extent to which a multiplex can be efficiently explored by a biased walk. Finally we show that, in real-world multiplex transportation networks, the trade-off between efficient navigation and resilience to link failure has resulted into systems whose diffusion properties are qualitatively different from those of appropriately randomised multiplex graphs. This fact suggests that multiplexity is an important ingredient to include in the modelling of real-world systems.

  3. Division: The Sleeping Dragon

    Science.gov (United States)

    Watson, Anne

    2012-01-01

    Of the four mathematical operators, division seems to not sit easily for many learners. Division is often described as "the odd one out". Pupils develop coping strategies that enable them to "get away with it". So, problems, misunderstandings, and misconceptions go unresolved perhaps for a lifetime. Why is this? Is it a case of "out of sight out…

  4. Division: The Sleeping Dragon

    Science.gov (United States)

    Watson, Anne

    2012-01-01

    Of the four mathematical operators, division seems to not sit easily for many learners. Division is often described as "the odd one out". Pupils develop coping strategies that enable them to "get away with it". So, problems, misunderstandings, and misconceptions go unresolved perhaps for a lifetime. Why is this? Is it a case of "out of sight out…

  5. Arithmetic of Division Fields

    CERN Document Server

    Brumer, Armand

    2011-01-01

    We study the arithmetic of division fields of semistable abelian varieties A over the rationals. The Galois group of the 2-division field of A is analyzed when the conductor is odd and squarefree. The irreducible semistable mod 2 representations of small conductor are determined under GRH. These results are used in "Paramodular abelian varieties of odd conductor," arXiv:1004.4699.

  6. On infinitely divisible semimartingales

    DEFF Research Database (Denmark)

    Basse-O'Connor, Andreas; Rosiński, Jan

    2015-01-01

    are strictly representable due to Hida's multiplicity theorem, the classical Stricker's theorem follows from our result. Another consequence is that the question when an infinitely divisible process is a semimartingale can often be reduced to a path property, when a certain associated infinitely divisible...

  7. Error-free 5.1 Tbit/s data generation on a single-wavelength channel using a 1.28 Tbaud symbol rate

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Galili, Michael; Oxenløwe, Leif Katsuo

    2009-01-01

    We demonstrate a record bit rate of 5.1 Tbit/s on a single wavelength using a 1.28 Tbaud OTDM symbol rate, DQPSK data-modulation, and polarisation-multiplexing. Error-free performance (BER......We demonstrate a record bit rate of 5.1 Tbit/s on a single wavelength using a 1.28 Tbaud OTDM symbol rate, DQPSK data-modulation, and polarisation-multiplexing. Error-free performance (BER...

  8. A wavelength-switchable single-longitudinal-mode dual-wavelength erbium-doped fiber laser for switchable microwave generation.

    Science.gov (United States)

    Pan, Shilong; Yao, Jianping

    2009-03-30

    A novel wavelength-switchable single-longitudinal-mode (SLM) dual-wavelength erbium-doped fiber laser (EDFL) implemented based on a sigma architecture that is composed of a ring loop and a linear standing wave arm is experimentally demonstrated. Gain competition that prevents stable dual-wavelength oscillation is effectively suppressed by placing the gain medium in the standing-wave arm and by introducing polarization hole burning (PHB) via polarization multiplexing of the two lasing wavelengths in the ring loop. The SLM operation is guaranteed by an ultranarrow Fabry- Perot filter (FPF) introduced by absorption saturation in an unpumped erbium-doped fiber (EDF) and the gain saturation in the gain medium. In addition, the ring cavity forms a Lyot filter for each wavelength. Thus, wavelength switching is achieved by simply adjusting the polarization state of either wavelength. By beating the two SLM wavelengths at a photodetector (PD), a microwave signal with a frequency tunable from approximately 10 to approximately 50 GHz is experimentally generated.

  9. Study on a Multiplexer a 40 Gb/s OTDM System

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In a 4×10Gb/s OTDM system (optical time-division-multiplication) system, multiplexing devices are key devices. The time interval of four channels of the 40Gb/s OTDM system is 25ps respectively. If the time intervals are no accurate, will induce the system performance to degeneration. In order to make out OTDM device and carry out a transmission experiment in a 40Gb/s OTDM system, a kind of OTDM device is researched. This scheme be used to fabricate multiplex device. Also the device have been used to a 4...

  10. Laguerre Gaussian beam multiplexing through turbulence

    CSIR Research Space (South Africa)

    Trichili, A

    2014-08-17

    Full Text Available We analyze the effect of atmospheric turbulence on the propagation of multiplexed Laguerre Gaussian modes. We present a method to multiplex Laguerre Gaussian modes using digital holograms and decompose the resulting field after encountering a...

  11. Sub-carrier and band hopped orthogonal frequency division multiple access (OFDMA) systems

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; Reynisson, Ragnar Vidir; Figueiredo, Daniel Vaz Pato

    2009-01-01

    This article proposes a novel way of grouping users in an orthogonal frequency division multiplexing (OFDM) communication link based on predefined criteria. The total available spectrum is divided into a number of bands equal to the number of groups. For efficient time-frequency resource allocati...

  12. Multi-species trace gas analysis with dual-wavelength quantum cascade laser

    Science.gov (United States)

    Jágerská, Jana; Tuzson, Béla; Looser, Herbert; Jouy, Pierre; Hugi, Andreas; Mangold, Markus; Soltic, Patrik; Faist, Jérôme; Emmenegger, Lukas

    2015-04-01

    Simultaneous detection of multiple gas species using mid-IR laser spectroscopy is highly appealing for a large variety of applications ranging from air quality monitoring, medical breath analysis to industrial process control. However, state-of-the-art distributed-feedback (DFB) mid-IR lasers are usually tunable only within a narrow spectral range, which generally leads to one-laser-one-compound measurement strategy. Thus, multi-species detection involves several lasers and elaborate beam combining solutions [1]. This makes them bulky, costly, and highly sensitive to optical alignment, which limits their field deployment. In this paper, we explore an alternative measurement concept based on a dual-wavelength quantum cascade laser (DW-QCL) [2]. Such a laser can emit at two spectrally distinct wavelengths using a succession of two DFB gratings with different periodicities and a common waveguide to produce one output beam. The laser design was optimized for NOx measurements and correspondingly emits single-mode at 5.26 and 6.25 μm. Electrical separation of the respective laser sections makes it possible to address each wavelength independently. Thereby, it is possible to detect NO and NO2 species with one laser using the same optical path, without any beam combining optics, i.e. in a compact and cost-efficient single-path optical setup. Operated in a time-division multiplexed mode, the spectrometer reaches detection limits at 100 s averaging of 0.5 and 1.5 ppb for NO2 and NO, respectively. The performance of the system was validated against the well-established chemiluminescence detection while measuring the NOx emissions on an automotive test-bench, as well as monitoring the pollution at a suburban site. [1] B. Tuzson, K. Zeyer, M. Steinbacher, J. B. McManus, D. D. Nelson, M. S. Zahniser, and L. Emmenegger, 'Selective measurements of NO, NO2 and NOy in the free troposphere using quantum cascade laser spectroscopy,' Atmospheric Measurement Techniques 6, 927-936 (2013

  13. Divisible ℤ-modules

    Directory of Open Access Journals (Sweden)

    Futa Yuichi

    2016-03-01

    Full Text Available In this article, we formalize the definition of divisible ℤ-module and its properties in the Mizar system [3]. We formally prove that any non-trivial divisible ℤ-modules are not finitely-generated.We introduce a divisible ℤ-module, equivalent to a vector space of a torsion-free ℤ-module with a coefficient ring ℚ. ℤ-modules are important for lattice problems, LLL (Lenstra, Lenstra and Lovász base reduction algorithm [15], cryptographic systems with lattices [16] and coding theory [8].

  14. Topology-optimized silicon photonic wire mode (de)multiplexer

    DEFF Research Database (Denmark)

    Frellsen, Louise Floor; Frandsen, Lars Hagedorn; Ding, Yunhong;

    2015-01-01

    of ~4.4 μm x ~2.8 μm and was fabricated for different design resolutions and design threshold values to verify the robustness of the structure to fabrication tolerances. The multiplexing functionality was confirmed by recording mode profiles using an infrared camera and vertical grating couplers. All...... structures were experimentally found to maintain functionality throughout a 100 nm wavelength range limited by available laser sources and insertion losses were generally lower than 1.3 dB. The cross talk was around -12 dB and the extinction ratio was measured to be better than 8 dB....

  15. Full-color hologram using spatial multiplexing of dielectric metasurface.

    Science.gov (United States)

    Zhao, Wenyu; Liu, Bingyi; Jiang, Huan; Song, Jie; Pei, Yanbo; Jiang, Yongyuan

    2016-01-01

    In this Letter, we demonstrate theoretically a full-color hologram using spatial multiplexing of dielectric metasurface for three primary colors, capable of reconstructing arbitrary RGB images. The discrete phase maps for the red, green, and blue components of the target image are extracted through a classical Gerchberg-Saxton algorithm and reside in the corresponding subcells of each pixel. Silicon nanobars supporting narrow spectral response at the wavelengths of the three primary colors are employed as the basic meta-atoms to imprint the Pancharatnam-Berry phase while maintaining minimum crosstalk between different colors. The reconstructed holographic images agree well with the target images making it promising for colorful display.

  16. On the Architecture and Design of Multi-Wavelength Passive Optical Arrayed Waveguide Grating Routers

    Directory of Open Access Journals (Sweden)

    Ali Hammadi

    2017-06-01

    Full Text Available Fiber to the premises (FTTP technology has become an attractive solution in the last two decades to overcome many limitations appeared with the wireless and copper based technologies in access network. Most of FTTP deployments are based on Passive Optical Network (PON technology. PONs have become so popular in the optics technology because of its growing reputation in not only providing high speed connectivity but also because of its immunity to EM interference, high security, long distance reach, low cost and low energy consumption. Arrayed Waveguide Grating (AWGs are passive optical devices that have been widely deployed and implemented in FTTP and many other applications. AWGs can serve as multiplexers, de-multiplexers, filters, routers, and as add/drop devices in many communication systems and optical based applications. In this paper, the AWG PON device is analyzed and simulated using Rsoft simulation tool for the design of multi wavelength optical passive multiplexer and de-multiplexer.

  17. Holographic data storage system combining shift-multiplexing with peristrophic-multiplexing

    Science.gov (United States)

    Yoshikawa, Kengo; Tsukamoto, Yu; Okubo, Kaito; Yamamoto, Manabu

    2014-02-01

    Holographic data storage (HDS) is a next-generation optical storage that uses the principles of holography. The multiplex holographic recording method is an important factor that affects the recording capacity of this storage. Various multiplex recording methods have been proposed so far. In this study, we focus on shift multiplexing with spherical waves and propose a method of shift multiplex recording that combines the peristrophic multiplexed recording. Simulation and experimental verification shows that the proposed method is effective in principle.

  18. Underwater Sound Reference Division

    Data.gov (United States)

    Federal Laboratory Consortium — The Underwater Sound Reference Division (USRD) serves as the U.S. standardizing activity in the area of underwater acoustic measurements, as the National Institute...

  19. Underwater Sound Reference Division

    Data.gov (United States)

    Federal Laboratory Consortium — The Underwater Sound Reference Division (USRD) serves as the U.S. standardizing activity in the area of underwater acoustic measurements, as the National Institute...

  20. On Geometric Infinite Divisibility

    OpenAIRE

    Sandhya, E.; Pillai, R. N.

    2014-01-01

    The notion of geometric version of an infinitely divisible law is introduced. Concepts parallel to attraction and partial attraction are developed and studied in the setup of geometric summing of random variables.