Polarization mode dispersion

About: Polarization mode dispersion is a research topic. Over the lifetime, 5147 publications have been published within this topic receiving 80055 citations. The topic is also known as: PMD.

Blind Density-Peak-Based Modulation Format Identification for Elastic Optical Networks

Abstract: Optical modulation format identification is critical in the next generation of heterogeneous and reconfigurable optical networks. Here, we present a blind modulation format identification method by applying fast density-peak-based pattern recognition in the autonomous receiver of elastic optical networks. In this paper, we find that the different modulation format types show different energy level features which can be used as a metric to identify these modulation formats in two-dimensional Stokes plane. The proposed method does not require training symbols, and is insensitive to carrier phase noise, frequency offset as well as polarization mixing. The effectiveness is verified via numerical simulations and experiments with PDM-BPSK, PDM-QPSK, PDM-8PSK, PDM-16PSK, PDM-8QAM, and PDM-16QAM. The results show that high identification accuracy can be realized using our proposed method over wide optical signal-to-noise ratio ranges. Meanwhile, we also discuss the influence of the residual chromatic dispersion, polarization mode dispersion, and polarization dependent loss impairments to our proposed method. We believe that the simple and flexible identification method would certainly bring a great convenience to the future optical networks.

Performance of a 46-Gbps Dual-Polarization QPSK Transceiver With Real-Time Coherent Equalization Over High PMD Fiber

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.

Polarization mode dispersion in a single mode fiber

Abstract: The Jones matrix method is used to measure the polarization mode dispersion (PMD) of a large variety of single mode fibers in the 1500 nm range. The dependence of PMD on wavelength, time, and temperature are studied in two different regimes: adiabatic and isothermal. In the adiabatic regime, time dependent stresses are introduced in the fiber by subjecting it to large and rapid changes in temperature. In this regime it is shown that the probability density function of PMD, obtained as a function of temperature and wavelength, fits very closely the theoretically predicted Maxwellian function. In the isothermal regime, the temperature of the fiber is held constant and the stresses are allowed to relax to their long term steady state conditions. In this regime the PMD exhibits a strong dependence on wavelength but otherwise is a bounded function which is nearly stationary with time. Test and analysis of the deterministic PMD in a specially constructed polarization maintaining fiber are used to study the dependence of PMD on temperature and wavelength. Finally, the system implications of this PMD study are described briefly.

Wavelength dispersion characteristics of single-mode fibers in low-loss region

Abstract: Wavelength dispersion characteristics of single-mode silica fibers in a very low-loss region, including zero dispersion wavelengths, are studied in detail using a "difference method." Wavelength dispersion of single-mode fibers is compared for fibers with same material dispersion but with different waveguide structure. Material dispersion is evaluated by extracting waveguide dispersion from experimental results. Effects of waveguide dispersion on the zero dispersion wavelength of the single-mode fiber in a longer wavelength region are clearly analyzed. Single-mode fiber design consideration is given from the wavelength dispersion point of view.

Demonstration of Phase-Conjugated Subcarrier Coding for Fiber Nonlinearity Compensation in CO-OFDM Transmission

Abstract: In this paper, we demonstrate through computer simulation and experiment a novel subcarrier coding scheme combined with pre-electrical dispersion compensation (pre-EDC) for fiber nonlinearity mitigation in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. As the frequency spacing in CO-OFDM systems is usually small (tens of MHz), neighbouring subcarriers tend to experience correlated nonlinear distortions after propagation over a fiber link. As a consequence, nonlinearity mitigation can be achieved by encoding and processing neighbouring OFDM subcarriers simultaneously. Herein, we propose to adopt the concept of dual phase conjugated twin wave for CO-OFDM transmission. Simulation and experimental results show that this simple technique combined with 50% pre-EDC can effectively offer up to 1.5 and 0.8 dB performance gains in CO-OFDM systems with BPSK and QPSK modulation formats, respectively.