Modeling and mitigation of polarization crosstalk-induced nonlinearity for the polarization-multiplexed carrier self-homodyne system

Abstract

In this Letter, we analytically model the impact of polarization crosstalk in the polarization-multiplexed carrier self-homodyne (PMC-SH) system with adaptive polarization control technology. When the optical paths of the signal and local oscillator (LO) are matched well, it is found that the polarization crosstalk results in a nonlinear shift on the constellation. Thus, we further propose a compensation scheme based on a low-complexity polynomial nonlinear equalizer (PNLE). Both simulation and experimental results validate our theoretical analysis. Moreover, the proposed PNLE-based compensation scheme achieves up to 1.23 dB tolerance improvement with respect to polarization crosstalk for 20 Gbaud 64QAM in the experiment.