Joint channel coding and fiber nonlinearity compensation with adaptive perturbation estimation in coherent optical transmission systems

A joint channel coding and fiber nonlinearity compensation scheme based on adaptive perturbation estimation is proposed for coherent optical transmission systems. The proposed PB-JCNC framework combines perturbation-based nonlinear modeling with iterative soft-information exchange from the forward error correction (FEC) decoder, enabling accurate estimation of nonlinear distortion without requiring precise knowledge of transmission link parameters. Simulation and experimental results demonstrate the effectiveness of the proposed method for both PDM-16QAM and PDM-64QAM signals. For 400 km PDM-64QAM transmission, a pre-FEC Q-factor improvement of up to 2.03 dB (simulation) and 1.46 dB (experiment) is achieved, along with a post-FEC launch power tolerance gain of up to 0.38 dB. For 1000 km PDM-16QAM transmission, consistent performance improvements are also observed. The results indicate that the PB-JCNC highlights the critical role of soft-information reliability in iterative nonlinear compensation.