PMD Tolerance of Various Modulation Formats in 40Gb/s DWDM Systems in Presence of Nonlinearities

Abstract

Different modulation formats are being used to mitigate either the PMD or the nonlinear effects. CSRZ-DPSKandCSRZ-DQPSKsystemsshowhighsuitabilityforultra-highspectralefficientDWDMsystemsandhighresiliencetodispersioncompensationtolerancesand fibernonlinearitiesbutacorrectpictureoftheirperformanceisabsent. Asthesymbolrateis reduced, the spectral width is also significantly reduced. A DQPSK signal at bit rate B has thesamespectralwidthasanOOKsignalatbit rateB/2, forRZwaveforms. Wehavemade an effort to quantify the effectiveness of CSRZ-DPSK and CSRZ-DQPSK in compensating PMD and also to find out their correlation. DQPSK has shown better PMD tolerance since it has the ability to double the spectral efficiency and relaxed dispersion management. We simulated single channel as well as multichannel optical fiber communication systems with varyingparameters. Theperformancesofthesystemsareevaluatedwithhighaswellaslow PMD coefficients in the presence or absence of nonlinear effects. The performance of the systems will be evaluated mainly in terms of graphical representations.