LAUSR

Abstract We propose a cross-phase modulation (XPM) mitigation method in wavelength division multiplexing (WDM) systems, which is enabled by the split nonlinearity compensation (NLC) and the modified decision directed recursive least square (DD-RLS) based nonlinear phase noise (NLPN) tracking algorithm. In the proposed method, the split NLC reduces the interaction between the dispersion and the XPM and makes the impact of the XPM on the signal more tend to the NLPN. Combined with the proposed modified DD-RLS algorithm, which can effectively track the fast-changing NLPN, the XPM effect in WDM systems can be mitigated. The proposed method is demonstrated by a WDM transmission simulation with 11 channels. The simulation results show that the proposed modified DD-RLS algorithm has better NLPN tracking ability and noise tolerance than the normal DD-RLS algorithm, and together with the split NLC, 0.8 dB Q2-factor improvement can be seen in the 1000-km transmission.