Cross-phase modulation in multispan WDM systems with arbitrary modulation formats

Cross-phase modulation (XPM) is a major performance-limiting effect in high bit-rate wavelength-division-multiplexed (WDM) networks with narrow channel spacing. In this paper, we present closed expressions for fast and accurate calculation of both XPM-induced amplitude and phase distortions of WDM channels. This is of particular importance for network optimization and examination of advanced modulation formats. By comparison with simulations, we demonstrate the wide application range of the novel method.