Polarization effects in dense WDM systems

Summary form only given. Polarization effects due to the complicated interaction of polarization mode dispersion (PMD), polarization dependent loss (PDL), and polarization dependent gain (PDG) can significantly impair optical fiber transmission systems and can even lead to fading, in which an entire channel is temporarily lost. When the PMD is not too large, these polarization effects are gross effects that act on an entire channel at once, unlike chromatic dispersion, the Kerr effect, and spontaneous emission noise, which affect individual bits. Thus, it is reasonable to calculate the penalties that these effects induce by following the Stokes parameters of each channel rather than attempting to follow the detailed temporal behavior. Indeed, it would be impractically expensive in computer time to determine the penalties by following the detailed temporal behavior since one must consider a large ensemble of fibers due to the random nature of the polarization effects. It is important to know the probability that a channel may drop due to those polarization effects in the long-distance trans-oceanic transmission systems. To model the effects of PMD, we use the coarse step method. In this approach, we periodically impose a fixed birefringence followed by a random rotation on the Poincare sphere.