The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Ivan B Djordjevic - One of the best experts on this subject based on the ideXlab platform.

  • Mode-Multiplexed Multi-Tb/s Superchannel Transmission With Advanced Multidimensional Signaling in the Presence of Fiber Nonlinearities
    IEEE Transactions on Communications, 2014
    Co-Authors: Ivan B Djordjevic, Milorad Cvijetic
    Abstract:

    We have analyzed the possibility of long-haul superchannel transmission with an aggregate serial bit rate exceeding 1 Tb/s by using the mode-multiplexed multidimensional signaling. We considered nonbinary quasi-cyclic LDPC-coded OFDM signals transmitted over few-mode Fibers (FMFs). The optimum vector-form nonlinear Schrödinger equation is developed to evaluate the performance of the proposed system. Both the impacts of nonlinear effects and nonlinear interaction between spatial modes have been included through the modified nonlinear Schrödinger equation we applied for the FMF case. Both two-dimensional and optimized four-dimensional (4D) signal constellations have been considered. To overcome the constraints imposed by the linear and nonlinear impairments in FMF, we proposed the use of block-coded modulation with advanced channel estimation and compensation techniques. We verified by means of simulation that the transmission of an aggregate serial bit rate of 1.2 Tb/s over 3000 km is achievable with a proposed LDPC-coded QPSK-OFDM format, whereas superchannel transmission with an aggregate serial rate of 2.4 Tb/s over 1800 km is achievable with the 16-QAM format. When a 4D 16-ary optimized constellation is used, we can extend the transmission distance of mode-multiplexed QPSK-OFDM by an additional 300 km.

  • ultimate information capacity of Fiber optic networks
    Proceedings of SPIE the International Society for Optical Engineering, 2010
    Co-Authors: Ivan B Djordjevic
    Abstract:

    There have been numerous attempts to determine the channel capacity of a nonlinear Fiber optics communication channel. The main approach, until recently, was to consider ASE noise as a predominant effect and to observe the Fiber Nonlinearities as the perturbation of linear case or as the multiplicative noise. In this invited paper, we describe how to determine the true Fiber-optics channel capacity. Because in most of practical applications the channel input distribution is uniform, we also describe how to determine the uniform information capacity, which represents the lower bound on channel capacity. This method consists of two steps: 1) approximating probability density functions (PDFs) for energy of pulses, which is done by one of the following approaches: (a) evaluation of histograms, (b) instanton approach or (c) edgeworth expansion, and 2) estimating information capacities by applying a method originally proposed by Arnold and Pfitser.

  • experimental demonstration of simultaneous compensation of polarization mode dispersion and Fiber Nonlinearities by ldpc coded turbo equalization
    Proceedings of SPIE the International Society for Optical Engineering, 2010
    Co-Authors: L L Minkov, Ivan B Djordjevic
    Abstract:

    In recent years LDPC codes have gained significant interest in the area of optical communication systems due to their capacity-approaching performance, high coding gain and low decoding-complexity. We describe the construction principles of high-rate, high-girth, quasi-cyclic LDPC codes and present an LDPC-coded turbo equalization scheme suitable for simultaneous mitigation of multiple transmission impairments. The equalization scheme is based on the maximum a posteriori probability detection, based on Bahl Cocke Jelinek Raviv (BCJR) algorithm that employs the conditional density probability functions of the channel to calculate the initial log-likelihood ratios for the LDPC decoder. To optimize the code performance extrinsic information transfer charts are used. We then investigate and evaluate the performance of the proposed scheme in the presence of polarization mode dispersion (PMD), Fiber Nonlinearities and chromatic dispersion for 10 Giga symbols/s transmission system and various modulation formats including NRZ and polarization-multiplexed BPSK with both direct and coherent detection. LDPC codes of rates 0.8, 0.9 and 0.95 are evaluated. Experiments with and without chromatic dispersion compensation are conducted.

  • suppression of Fiber Nonlinearities and pmd in coded modulation schemes with coherent detection by using turbo equalization
    IEEE\ OSA Journal of Optical Communications and Networking, 2009
    Co-Authors: Ivan B Djordjevic, L L Minkov, Ting Wang
    Abstract:

    We propose a maximum a posteriori probability (MAP) turbo equalizer based on the sliding-window multilevel Bahl-Cocke-Jelinek-Raviv algorithm. This scheme is suitable for simultaneous nonlinear and linear impairment mitigation in multilevel coded-modulation schemes with coherent detection. The proposed scheme employs large-girth quasicyclic LDPC codes as channel codes. We demonstrate the efficiency of this method in dealing with Fiber Nonlinearities by performing Monte Carlo simulations. In addition, we provide the experimental results that demonstrate the efficiency of this method in dealing with polarization mode dispersion. We also study the ultimate channel capacity limits, assuming an independent identically distributed source.

  • achievable information rates for high speed long haul optical transmission
    Journal of Lightwave Technology, 2005
    Co-Authors: Ivan B Djordjevic, Bane Vasic, M Ivkovic, Ildar R Gabitov
    Abstract:

    There have been numerous attempts to determine the channel capacity of a nonlinear Fiber-optic communication channel. The main approach was to consider amplified spontaneous emission (ASE) noise as a predominant effect and to observe the Fiber Nonlinearities as the perturbation of a linear case or as the multiplicative noise. In this paper, the achievable information rates for high-speed optical transmission (40 Gb/s and above) are calculated using the finite-state-machine approach. In calculations, the combined effect of ASE noise, Kerr nonlinearity [self-phase modulation (SPM), intrachannel four-wave mixing (IFWM), intrachannel cross-phase modulation (IXPM)], stimulated Raman scattering (SRS), chromatic dispersion, and (optical/electrical) filtering is taken into account.

Magnus Karlsson - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation of link impairments in pilot tone aided superchannel transmission
    IEEE Photonics Technology Letters, 2019
    Co-Authors: Mikael Mazur, Abel Lorencesriesgo, Jochen Schroeder, Magnus Karlsson
    Abstract:

    We investigate the performance of single-pilot-tone locked frequency comb-based superchannel transmission for distances up to 1200km. In our scheme, electro-optic transmitter and receiver combs are locked by leaving one of the transmitter carriers unmodulated and regenerating the receiver comb via optical injection locking. This approach significantly reduces carrier offsets and therefore leads to reduced digital signal processing complexity. We experimentally assess how transmission impairments such as noise added by optical amplifiers and Fiber Nonlinearities affect the quality of the comb regeneration. Our results show that while the operating conditions are more stringent at longer distances, the single pilot is robust to impairments. At optimal launch power, similar performance with respect to an intradyne receiver is observed, showing that the optical pilot tones can be co-transmitted with data channels even at distances spanning hundreds of kilometer. The total superchannel spectral efficiency (throughput), including the pilot tone and guardbands, is 9.6 bits/s/Hz (12 Tbit/s) after 480 km and 8.4 bits/s/Hz (10.5 Tbit/s) after 960km.

  • mitigation of nonlinear distortion in hybrid raman phase sensitive amplifier links
    Optics Express, 2016
    Co-Authors: Henrik Eliasson, Samuel L. I. Olsson, Magnus Karlsson
    Abstract:

    Hybrid systems combining distributed Raman amplification and phase-sensitive amplifiers (PSAs) are investigated in numerical simulations. We focus on the mitigation of Fiber Nonlinearities and the impact of the span power map which is also important in systems employing optical phase conjugation or phase-conjugated twin waves. We simulate multi-span PSA links with and without distributed Raman amplification and show that by including distributed Raman amplification, the transmission distance increases more at optimum launch power than in the linear regime. For a 5-channel WDM QPSK PSA-amplified system, we observe a transmission reach increase by a factor of 8.1 by including ideal distributed Raman amplification.

P Bayvel - One of the best experts on this subject based on the ideXlab platform.

  • high order modulation formats constellation design and digital signal processing for high speed transmission systems
    2020
    Co-Authors: Gabriele Liga, P Bayvel
    Abstract:

    Abstract The capacity of optical Fiber communication networks is limited by the Kerr effect inherent to transmission using optical Fibers. The signal degradations due to the nonlinear distortions limit the achievable transmission distances and become more significant in systems with larger transmission bandwidths, closer channel spacing, and higher order modulation formats. Optical Fiber Nonlinearities are seen as the major bottleneck to the performance of optical transmission networks. This chapter describes the theoretical and experimental investigations into a series of techniques developed to unlock the capacity of optical communications and to overcome the barriers in transmission over nonlinear Fiber channels. It covers three key areas for combatting optical Fiber Nonlinearities to increasing the overall throughput of the optical Fiber channels in the nonlinear regime that have been the focus of research over the recent years. These are (1) digital nonlinearity compensation technique, such as digital backpropagation, to partially “undo” the nonlinearity and improve signal performance, (2) digital nonlinearity compensation in presence of laser phase noise, and (3) signal design techniques, making use of coded modulation and constellation shaping in optical communications. This chapter aims to review and quantify examples of digital signal processing-based nonlinearity compensation and further possible increases in the achievable capacity and transmission distances, depending on the modulation format used, that come from the combination of nonlinearity compensation and signal constellation shaping.

  • information rate in ultra wideband optical Fiber communication systems accounting for high order dispersion
    arXiv: Signal Processing, 2019
    Co-Authors: Nikita A Shevchenko, Tianhua Xu, Domanic Lavery, R I Killey, P Bayvel
    Abstract:

    The effect of Kerr-induced optical Fiber Nonlinearities in C-band (5 THz) EDFA and C+L-band (12.5 THz) Raman-amplified optical communication systems have been studied considering the impact of third-order Fiber dispersion. The performance of digital nonlinearity compensation with single channel and 250 GHz bandwidth in both EDFA and Raman amplified systems has been investigated, respectively. The achievable information rates (AIRs) and optimum code rates in each individual transmission channel have been evaluated for the DP-64QAM, the DP-256QAM and the DP-1024QAM modulation formats. It is found that, for all considered modulation formats, the signal-to-noise ratios, AIRs and code rates exhibit significantly asymmetric behaviour about the central channel due to the presence of the third-order dispersion. This provides a new insight that the forward error correction schemes have to be optimized asymmetrically, on a per-channel basis, to maximize the overall throughput.

  • digital signal processing dsp and its application in optical communication systems
    Optical Fiber Telecommunications (Sixth Edition)#R##N#Systems and Networks, 2013
    Co-Authors: P Bayvel, Carsten Behrens, David S Millar
    Abstract:

    The key question of current optical communications research is: how to maximize both capacity and transmission distance in future optical transmission networks by using spectrally-efficient modulation formats with coherent detection, and how can digital signal processing aid in this quest? There is a clear trade-off between spectral efficiency and transmission distance, since the more spectrally-efficient modulation formats are also more susceptible to optical Fiber Nonlinearities. This chapter illustrates the application of nonlinear backpropagation to mitigate for both linear and nonlinear transmission impairments for a range of modulation formats, at varying symbol-rates and wavelength spacings, and also by varying the signal bandwidth which is backpropagated. The basics of coherent receiver structure and DSP algorithms for chromatic dispersion compensation, equalization and phase recovery of PDM-BPSK, PS-QPSK, PDM-QPSK, PDM-8PSK, PDM-8QAM, and PDM-16QAM are reviewed and the effectiveness of the nonlinearity compensating DSP based on digital backpropagation is explored. This chapter includes a comprehensive literature review of the key experimental demonstrations of nonlinearity-compensating DSP.

Peter Magill - One of the best experts on this subject based on the ideXlab platform.

  • performance of a 46 gbps dual polarization qpsk transceiver with real time coherent equalization over high pmd Fiber
    Journal of Lightwave Technology, 2009
    Co-Authors: L E Nelson, S L Woodward, Xiang Zhou, M D Feuer, D Hanson, Doug Mcghan, M Moyer, M O Sullivan, Peter Magill
    Abstract:

    We report experimental results on the transmission performance of a coherent dual-polarization quadrature phase-shift-keyed (DP-QPSK) transceiver with real-time electronic equalization over Fiber having 50-ps mean polarization mode dispersion (PMD). Both single-channel, single-span and multi-channel, multi-span measurements were performed over the high PMD Fiber, which has near Maxwellian statistics for the differential group delay (DGD) as well as higher order PMD as expected for a long, mode-coupled Fiber. Transmission of eighty channels was achieved over 8 times100 km of TrueWave Reduced Slope Fiber plus distributed high PMD Fiber, where individual channels had instantaneous DGD as high as 127 ps. The dependence of the OSNR penalty on the launch state of polarization was evaluated and found to be minimal, and the contribution of Fiber Nonlinearities to the transmission penalty was evaluated for two different per-channel launch powers. Finally, using a transceiver equipped with forward-error-correction, error-free transmission over the 800-km link was demonstrated over a 10-day period; during this time the DGD of the measured channel varied from 13 to 116 ps.

  • performance of a 46 gbps dual polarization qpsk transceiver with real time coherent equalization over high pmd Fiber
    OFC NFOEC 2008, 2009
    Co-Authors: L E Nelson, S L Woodward, Xiang Zhou, M D Feuer, D Hanson, Doug Mcghan, M Moyer, M O Sullivan, Peter Magill
    Abstract:

    We report experimental results on the transmission performance of a coherent dual-polarization quadrature phase-shift-keyed (DP-QPSK) transceiver with real-time electronic equalization over Fiber having 50-ps mean polarization mode dispersion (PMD). Both single-channel, single-span and multi-channel, multi-span measurements were performed over the high PMD Fiber, which has near Maxwellian statistics for the differential group delay (DGD) as well as higher order PMD as expected for a long, mode-coupled Fiber. Transmission of eighty channels was achieved over 8 x 100 km of TrueWave Reduced Slope Fiber plus distributed high PMD Fiber, where individual channels had instantaneous DGD as high as 127 ps. The dependence of the OSNR penalty on the launch state of polarization was evaluated and found to be minimal, and the contribution of Fiber Nonlinearities to the transmission penalty was evaluated for two different per-channel launch powers. Finally, using a transceiver equipped with forward-error-correction, error-free transmission over the 800-km link was demonstrated over a 10-day period; during this time the DGD of the measured channel varied from 13 to 116 ps.

Chongjin Xie - One of the best experts on this subject based on the ideXlab platform.

  • Fiber nonlinearity compensation of an 8 channel wdm pdm qpsk signal using multiple phase conjugations
    Optical Fiber Communication Conference, 2014
    Co-Authors: R M Jopson, Chongjin Xie, A H Gnauck, M Dinu, S Chandrasekhar, Xiang Liu, M Montoliu, S Randel, C J Mckinstrie
    Abstract:

    We demonstrate compensation of Fiber Nonlinearities using optical phase conjugation of an 8-channel WDM 32-Gbaud PDM QPSK signal. Conjugating phase every 600 km in a Fiber loop enabled a 6000 km transmission over TrueWave Fiber.

  • Fiber Nonlinearities in 16qam transmission systems
    European Conference on Optical Communication, 2011
    Co-Authors: Chongjin Xie
    Abstract:

    Nonlinear effects in 28-Gbaud 16QAM transmission with and without inline dispersion compensation are studied. We find that SPM and XPM induced nonlinear phase distortions significantly degrade the performance of 16QAM transmission with inline dispersion compensation.

  • Fiber Nonlinearities in coherent optial communication systems
    International Conference on Optical Communications and Networks, 2011
    Co-Authors: Chongjin Xie
    Abstract:

    We describe the impact of Fiber nonlinear effects in coherent optical communication systems and discuss some nonlinearity compensation techniques. (2 pages)

  • WDM coherent PDM-QPSK systems with and without inline optical dispersion compensation
    Optics express, 2009
    Co-Authors: Chongjin Xie
    Abstract:

    Using numerical simulations, we study and compare the performance of 42.8-Gb/s and 112-Gb/s intradyne coherent polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) systems in wavelength-division-multiplexed (WDM) transmission with inline dispersion compensation Fiber (DCF) and that with fully electronic dispersion compensation. Two effects are considered in the studies. One is Fiber Nonlinearities and the other is the local oscillator (LO) phase noise to amplitude noise conversion induced by electronic dispersion compensation. Results of 1000-km transmission employing standard single-mode Fiber (SSMF) show that, for non-return-to-zero (NRZ) PDM-QPSK, both the 42.8-Gb/s and 112-Gb/s WDM systems with DCF have less tolerance to Fiber Nonlinearities than those with electronic dispersion compensation due to nonlinear polarization scattering. However, by using time-interleaved return-to-zero (RZ) PDM-QPSK, which can significantly suppress nonlinear polarization scattering in a system with inline DCF, the 42.8-Gb/s system with DCF can achieve better performance than that with electronic dispersion compensation, and comparable performance can be obtained for the 112-Gb/s system with DCF and that with electronic dispersion compensation. We find that the LO phase noise to amplitude noise conversion can cause significant penalties in the 112-Gb/s system with only electronic dispersion compensation if distributed feedback lasers are used.