Geometric Shaping of 2-D Constellations in the Presence of Laser Phase Noise

In this article, we propose a geometric shaping (GS) strategy to design 8, 16, 32, and 64-ary modulation formats for the optical fibre channel impaired by both additive white Gaussian (AWGN) phase noise. The constellations were optimised maximise generalised mutual information (GMI) using mismatched model. presented demonstrate an enhanced signal-to-noise ratio (SNR) tolerance in high noise regimes when compared with their quadrature amplitude (QAM) or AWGN-optimised counterparts. By putting optimisation results context of 400ZR implementation agreement, show that GS alone can either relax laser linewidth (LW) carrier estimation (CPE) requirements 400 Gbit/s transmission links beyond. Following GMI validation, performance was examined terms post forward error correction (FEC) bit-error-rate (BER) soft decision (SD) extended Hamming code (128, 120), implemented as per agreement. We gains up 1.2 dB AWGN shaped formats.