Optical Nonlinear-Phase-Noise Compensation for 32 Gbaud PolDM-16QAM Transmission Using a Code-Aided Expectation-Maximization Algorithm

Nonlinearity induced phase noise has become a major obstacle in long-haul coherent fiber-optic communication systems. It has been shown to be signal dependent and hence correlated over time. We propose a code-aided expectationmaximization algorithm to mitigate such nonlinear phase noise. It iteratively utilizes both the time correlation of nonlinearity, and a soft-decision error control code. Simulation and experimental results show that on a dual polarization wavelength division multiplexed 16 QAM system, launch power tolerance can be increased by 2 dBm, and optical signal to noise ratio requirement can be relaxed by 0:3 dB to achieve the same Q2-factor.