Mitigation of nonlinearity based on optimized percentage of dispersion pre-compensation in coherent optical PDM-OFDM systems

The one-step nonlinearity compensation method, i.e., nonlinear phase rotation (NPR), is shown to be affected by the amount of pre-compensated dispersion for coherent optical OFDM system with a dispersion unmanaged link. It is observed that NPR plus optimal percentage, around 50%, of dispersion pre-compensation is performing better than 1-step digital back-propagation (BP), with the same computational complexity. The optimized scheme results in a 2-dBm improvement in optimal launch power as well as 1.75-dB improvement in optimal signal quality compared to 1-step BP after 800-km transmission at the bit rate of 20 Gb/s.