Impact of Interchannel Nonlinearities on a Split-Step Intrachannel Nonlinear Equalizer

Abstract

We experimentally investigate the use of split-step intrachannel nonlinear equalizer, for a wavelength-division-multiplexed (WDM) 112-Gb/s nonreturn-to-zero polarization-division-multiplexed quadri-phase-shift keying system using a digital coherent receiver. Our investigations demonstrate that the nonlinear compensation algorithm can increase the reach by 23% in a 100-GHz spacing WDM link compared to 46% for the single-channel case. When the channel spacing is reduced to 50 GHz, the reach improvement is minimal due to the uncompensated interchannel nonlinearities; nevertheless, the system robustness is improved as the system operating power dynamic range is widened by 2 dB.