The interplay between nonlinear effects in modern optical communications systems

Summary form only given. The authors review the guidelines for the design of modern optical communications systems, considering primarily the penalties and limitations posed by nonlinear effects in optical fibers. In WDM systems, nonlinear optical effects are traditionally divided into two categories. The first consists of intra-channel impairments where fiber nonlinearities interact with the transmitted waveform in a way that results in self imposed distortions, a mechanism known as self phase modulation. The second category consists of inter-channel effects, where the distortions experienced by one channel result from the propagation of other channels that are transmitted at other optical frequencies, mediated by fiber nonlinearities. The main nonlinear mechanisms that belong to this category are four-wave mixing, cross-phase modulation and stimulated Raman scattering.