Polarization evolution due to the Kerr nonlinearity and chromatic dispersion

This paper numerically investigated the evolution of the degree of polariza tion of individual channels and their Stokes parameters in a wavelength div ision multiplexed (WDM) system in which Kerr nonlinearity and chromatic dis persion are taken into account but in which polarization mode dispersion as well as polarization-dependent loss and gain are neglected. We compared th e results to a mean field model which assumes that the channels are strongl y dispersion-managed so that each channel is only affected by the Stokes pa rameters of the others, This model predicts no change in the degree of pola rization of each of the channels so that an initially polarization-scramble d channel does not repolarize, The full simulations showed that the repolar ization of a polarization-scrambled signal is small for parameters correspo nding to realistic communication systems, validating the use of the mean fi eld model. However, me also found that the repolarization can become signif icant for low data rates and a small number of channels in a dispersion-man aged system with a short length map, thus setting limits on the model's val idity and indicating operating regimes that should be avoided. in real comm unication systems.