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.

Adaptive digital equalization in the presence of chromatic dispersion, PMD, and phase noise in coherent fiber optic systems

Abstract: Chromatic dispersion (CD) and polarization mode dispersion (PMD) severely limit the performance of optical transmission systems operating at and above 10 Gb/s. Electrical equalization techniques have been proposed to compensate dispersion in both coherent and intensity modulation/direct-detection (IM/DD) systems. We investigate the combined adaptive digital equalization of all-order PMD, CD, and laser phase noise in high-speed coherent optical transmission systems. Simultaneous equalization of these impairments has not been reported previously and is particularly important in modulation systems that exploit polarization to increase modulation efficiency. We propose a novel 4-dimensional equalizer structure for joint polarization modulation and M-ary differential phase shift keying (JPMDPSK) systems. The specific example considered is 40 Gb/s transmission with a 10 GBaud symbol rate, using DQPSK modulation on each axis of polarization. Our results show that the new four-dimensional equalizer can compensate channel dispersion of up to 1000 km of standard single-mode fiber, with less than 3 dB penalty in signal-to-noise ratio (SNR). This is a dramatic improvement over 40 Gb/s IM/DD systems. The feasibility of the very large scale integration (VLSI) of coherent receivers in current technology is also discussed.

Optical Performance Monitoring of Phase-Modulated Signals Using Asynchronous Amplitude Histogram Analysis

Abstract: As optical networks continue to grow towards high capacity and high flexibility, new transmission technologies are being introduced. In order to maintain the quality of signal and control over network in the transparent domains, optical performance monitoring (OPM) systems are becoming a necessity. Phase modulation formats emerge as the solution of choice in transparent domains because of their sensitivity, spectral efficiency, and resilience to optical impairments. In this paper, we demonstrate a flexible OPM method for phase-modulated signals using asynchronous amplitude histogram analysis. We show numerically and experimentally the monitoring of optical signal-to-noise ratio (OSNR), chromatic dispersion (CD), and polarization-mode dispersion (PMD) for differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) signals. The OSNR can be measured within range of 20-35 dB and accumulated chromatic dispersion between 600 and 600 ps/nm. The asynchronous amplitude histogram monitoring method is proved to be a precise and versatile monitoring tool for high-capacity optical networks.

Measurement of depolarization and scaling associated with second-order polarization mode dispersion in optical fibers

Abstract: The Muller matrix method enables the low-noise, high-resolution measurement of second-order polarization-mode-dispersion (PMD) depolarization and related parameters required for systems modeling. We report experimental observations of second-order PMD statistical dependencies and scaling for fibers with mean differential group delay (DGD) ranging from 1.3 to 17.0 ps. Measurements of 10 different fibers confirm that the depolarization scales with the mean DGD while the polarization-dependent chromatic dispersion scales with the square of the mean DGD.

Limitations in 10 Gb/s WDM optical-fiber transmission when using a variety of fiber types to manage dispersion and nonlinearities

Abstract: We analyze the system limitations of WDM transmission when using various types of optical fiber to manage dispersion and nonlinearities. In our model, from two to eight 10 Gb/s WDM channels are transmitted through a cascade of EDFA's experiencing dispersion, stimulated Raman scattering, and self- and cross-phase modulation. The fiber types modeled include: conventional single-mode fiber, dispersion shifted fiber, and dispersion-compensating fiber. These fibers have different dispersion spectral profiles and are combined to manage dispersion to produce a total zero dispersion for a certain fiber span while eliminating four-wave mixing. We find that a system using dispersion-shifted fiber and conventional single-mode fiber exhibits the best performance, with the combination of dispersion and cross-phase modulation as the dominant effects. Furthermore, conventional single-mode fiber combined with dispersion-compensating fiber system exhibits the worst performance, with the combination of dispersion and self-phase modulation as the dominant effects.

Fiber designs with significantly reduced nonlinearity for very long distance transmission.

Abstract: A class of low-nonlinearity dispersion-shifted fibers based on depressed-core multistep index profiles is investigated. A systematic approach for designing these fibers in which a reference W-index profile is used to initiate the design is presented. Transmission properties, including effective area, mode-field diameter, dispersion, dispersion slope, and cutoff wavelength, are evaluated for several design examples. The effects of varying fiber dimensions and indices on effective area and mode-field diameter are assessed. It is shown that there is a trade-off between these two properties and, generally, larger effective areas are associated with larger mode-field diameters. Dispersion-shifted single-mode fiber designs with effective areas of from 78 to 210 microm2 and the corresponding mode-field diameter of from 8.94 to 14.94 microm, dispersion less than 0.07 ps/nm km, and dispersion slope of approximately 0.05 ps/nm2 km are presented.