Probabilistically Shaped Rate-Adaptive Polar-Coded 256-QAM WDM Optical Transmission System

Abstract

In this paper, a rate-adaptive coded modulation (CM) system combining polar codes and many-to-one probabilistic shaping is constructed and experimentally demonstrated. We propose to control the polar codes using a fraction of bits referred to as pre-set bits. This not only allows to offset the puncturing loss of rate-adaptive polar codes but also provides shaping gains compared to the non-punctured polar codes. Preset bits and many-to-one shaping are combined to form a rateadaptive bit-interleaved CM system. We experimentally evaluate the system performance for 10×8-GBd dual polarization 256 quadrature amplitude modulation (QAM) wavelength division multiplexed (WDM) system with various input data rates ranging from 61 Gbps to 91 Gbps per carrier. The experimental results demonstrate a 200 km reach increase over a wide range of distances compared to the non-punctured polar codes and punctured polar codes.

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