Nonlinear phase noise reduction using digital back propagation and midpoint optical phase conjugation.

We introduce a new system configuration to reduce the nonlinear phase noise (NLPN) by splitting the digital back propagation (DBP) between transmitter and receiver, asymmetrically, along with using mid-line optical phase conjugation (OPC). Our analytical results show that the variance of NLPN reduces by a factor of 16 compared to the standard configuration which is the dispersion uncompensated fiber optic link with full DBP at the receiver, i.e., the back propagation for the fiber spans is done entirely at the receiver. Numerical simulations show the same trend as predicted by the analytical model, and show about 2.6 dB and 2 dB improvement in Q-factor, for single channel and 5-channel WDM systems, respectively.