Impact of Polarization Mode Dispersion and Cross Phase Modulation in a WDM/IM-DD Transmission System

Cross-phase modulation (XPM) changes the state-of-polarization (SOP) of the channels that leads to amplitude modulation of the propagating waves in a WDM system. Due to the presence of polarization mode dispersion (PMD), the angles between the SOP of the channels change randomly and the modulation amplitude fluctuation in the perturbed channel becomes random. We analytically derive the dynamic equation of the perturbed channel, determine the combined probability density function of the random angle between the SOP of pumps and probe channel and evaluate the impact of PMD on XPM for a 4-channel IM-DD WDM system in terms of BER at bit rate of 10 Gbit/s per channel. We also simulate the interaction PMD and XPM for a 4-channel WDM system in terms of eye diagram and found that eye opening penalty is 1.85 dB more when the fiber PMD coefficient increases from 0.5 ps/radickm to 1.5 ps/radickm.