Transmission method of improved fiber nonlinearity tolerance for probabilistic amplitude shaping

Abstract

For probabilistic amplitude shaping (PAS), we propose a super-symbol transmission method that improves fiber nonlinearity tolerance. A simple fiber nonlinearity low-pass filtering model, as well as its interaction with the spectral dip of signal's intensity waveform, is provided to explain the origin of this nonlinear benefit. With 25-GHz-spaced, 26 × 22.5 GBaud dual-polarized PAS-64 quadrature amplitude modulation (QAM) signals transmitted over 12 spans of 80-km standard single mode fiber (SSMF), the proposed method is found to provide ∼0.15-dB gain over the previous finite-blocklength method with intra-DM pairing, ∼0.26-dB gain over finite-blocklength method with inter-DM pairing, and ∼0.44-dB benefit over the traditional method, all with a feasible blocklength at 200.