NLIN Mitigation Using Turbo Equalization and an Extended Kalman Smoother

We develop a method for inter-channel nonlinear interference noise (NLIN) mitigation, based on Turbo equalization and an extended Kalman smoother. The method exploits both the unique statistical properties of NLIN and soft-decision information from the code structure, to obtain improved channel state estimation and symbol detection. The error-free information rate is improved by up to 0.3 b/symbols/polarization, for a 1000 km, 64-QAM, 32 Gbaud transmission over standard fiber.