Performance of different modulation formats in 40 Gb/s optical systems in the presence of polarization mode dispersion and nonlinear effects
10 Apr 2014-pp 1-4
TL;DR: In this paper, different modulation formats in optical fiber systems in the presence of polarization mode dispersion (PMD) and fiber nonlinearities were simulated and the performance of different formats was compared in terms of differential group delay (DGD).
Abstract: We simulated different modulation formats in optical fiber systems in the presence of polarization mode dispersion (PMD) and fiber nonlinearities. Non-return-to-zero (NRZ), return-to-zero (RZ), chirped RZ (CRZ), carrier suppressed RZ (CSRZ), duobinary, differential phase shift keying (DPSK), differential quadrature phase shift keying (DQPSK) and CSRZ-DQPSK formats are simulated. The maximum data rate used in the system is 40 Gb/s and the length of the fiber is kept fixed at 100 km. Standard communication fiber models are used. Monte Carlo simulation method is used for high and low PMD coefficients and for varied nonlinear coefficients. The performance of different formats is compared in terms of differential group delay (DGD). The results show that RZ-DQPSK is better PMD tolerant in the presence of nonlinearities.
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Proceedings Article•
06 Mar 2005TL;DR: The magnitude and direction of the polarization mode dispersion vector of a WDM channel is significantly affected by nonlinear polarization crosstalk from neighbouring channels within the PMD correlation bandwidth.
Abstract: The magnitude and direction of the Polarization Mode Dispersion vector of a WDM channel is significantly affected by nonlinear polarization crosstalk from neighbouring channels within the PMD correlation bandwidth. Such non-linear interactions may further significantly impair dynamic networks.
2 citations
Dissertation•
30 Aug 2016
TL;DR: In this article, the authors propose a method to solve the problem of "uniformity" and "uncertainty" in the context of education.iii.iiiiii.
Abstract: iii
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...[38] presented simulation for various modualtion formats in optical fibers communication in presence of PMD and nonlinearities....
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References
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TL;DR: In this article, the authors review high-spectral-efficiency optical modulation formats for use in digital coherent systems and highlight important trade-offs pertaining to the design and performance of coherent higher-order QAM transponders.
Abstract: As 100-Gb/s coherent systems based on polarization- division multiplexed quadrature phase shift keying (PDM-QPSK), with aggregate wavelength-division multiplexed (WDM) capacities close to 10 Tb/s, are getting widely deployed, the use of high-spectral-efficiency quadrature amplitude modulation (QAM) to increase both per-channel interface rates and aggregate WDM capacities is the next evolutionary step. In this paper we review high-spectral-efficiency optical modulation formats for use in digital coherent systems. We look at fundamental as well as at technological scaling trends and highlight important trade-offs pertaining to the design and performance of coherent higher-order QAM transponders.
360 citations
TL;DR: In this paper, the Manakov-PMD equation was derived using multiple-length-scale techniques and it was shown that the scalar nonlinear Schro/spl uml/dinger equation is valid when the signal is initially in a single polarization state.
Abstract: Aspects of the interaction of the Kerr nonlinearity and polarization mode dispersion (PMD) are reviewed. The basic equation that governs this interaction on the length scale of interest in optical fiber communications systems is the Manakov-PMD equation. This equation is derived using multiple-length-scale techniques. The focus of the derivation is the elucidation of common misunderstandings and pitfalls rather than mathematical rigor. It is shown that the scalar nonlinear Schro/spl uml/dinger equation is valid when PMD is absent and the signal is initially in a single polarization state. Two examples are then presented that illustrate the complexity of the interaction between nonlinearity and PMD. The first example considers the interaction of a nonlinearly induced chirp with PMD. As the power increases, one can obtain an improved eye opening relative to the case when PMD is absent. The second example considers the effect of nonlinear polarization rotation in a wavelength-division-multiplexed system. When nonlinear polarization rotation is important, the principal states of polarization become time dependent and PMD compensation becomes ineffective. This problem can be mitigated through the use of line codes.
138 citations
TL;DR: In this paper, the authors discuss how cross-polarization modulation (XPolM) affects PMD and PMD-induced outage probabilities in fiber-communication systems by providing analytical formulas for the OP with and without XPolM.
Abstract: It is well known that cross-phase-modulation-induced polarization rotation, cross-polarization modulation (XPolM), significantly degrades the performance of polarization-mode-dispersion (PMD) compensators. In this paper, the research on XPolM is reviewed, unique simulations of XPolM in the presence of walk off are presented, and some pitfalls are demonstrated with respect to choice of data streams in such simulations. Then, the authors discuss how XPolM affects PMD and PMD-induced outage probabilities (OP) in fiber-communication systems by providing analytical formulas for the OP with and without XPolM. Finally, the XPolM and PMD compensation are tied together by giving simple rules of thumb for when XPolM degrades PMD compensated systems, and PMD mitigation methods that are robust to XPolM are discussed
73 citations
TL;DR: In this paper, the design of a polarization de-multiplexer and a polarization mode dispersion compensator for direct-detect polarization division multiplexed (PDM) return-to-zero differential quadrature phase shift keying (RZ-DQPSK) systems are studied in detail.
Abstract: The design of a polarization de-multiplexer and a polarization mode dispersion compensator (PMDC) for direct-detect polarization division multiplexed (PDM) return-to-zero differential quadrature phase shift keying (RZ-DQPSK) systems are studied in detail. The impact of polarization dependent loss is studied in polarization de-multiplexers with different error detection configurations for both bit-aligned and bit-interleaved PDM systems. The level of the clock frequency of the combined pulse train of the two polarizations is proposed as the error signal for the PMDC. It enables the PMDC to work in the cancellation mode. Two separate control loops are proposed for the polarization de-multiplexer and the PMDC to allow them to work independently. The DGD tolerances for the one-stage and two-stage PMDC are measured and discussed. Finally the glitch problem in the polarization tuning algorithm is studied. An advanced dithering algorithm and the corresponding architecture of the polarization controller are proposed to solve the glitch problem.
26 citations
TL;DR: In this paper, a parallel programming implementation of the multicanonical Monte Carlo method is developed, which automatically performs concurrent loop computation on multicore processors, for the estimation of the tails of the outage probability distribution.
Abstract: Polarization division multiplexed (PDM) quadrature phase-shift keying (QPSK) coherent optical systems employ blind adaptive linear electronic equalizers for polarization-mode dispersion (PMD) compensation. In this paper, we compute the performance of various adaptive, fractionally spaced, feed-forward electronic equalizers, using the outage probability as a criterion. A parallel programming implementation of the multicanonical Monte Carlo method is developed, which automatically performs concurrent loop computation on multicore processors, for the estimation of the tails of the outage probability distribution. The constant modulus algorithm (CMA), the decision-directed least mean squares (DD-LMS), and their combination are applied for the adaptation of electronic equalizer filter coefficients. In the exclusive presence of PMD, we demonstrate that half-symbol-period-spaced CMA-based adaptive electronic equalizers perform slightly better than their DD-LMS counterparts, at links with strong PMD, whereas the opposite holds true at the weak PMD regime. It is shown that the successive application of CMA and DD-LMS with 20 complex, half-symbol-period-spaced taps per finite impulse response filter is adequate to reduce the outage probability of coherent PDM QPSK systems to less than 10-5, for a mean differential group delay of more than twice the symbol period.
13 citations