A probabilistic shaping method based on intrinsic bit-level labeling and asymmetric polygon modulation for optical interconnects

This paper proposes a probabilistic shaping method based on intrinsic bit-level labeling and asymmetric polygon modulation for optical interconnects, which can significantly improve the system performance in power consumption and bit error rate. An experiment of 35.6 Gb/s 32-to-8 probabilistic shaping carrierless amplitude and phase (CAP) data transmission using intensity-modulation and direct-detection system (IMDD) over 25 km standard single-mode fiber (SSMF) is successfully demonstrated to show the superiority. Results show that the system performance is improved by more than 4 dB at the 1×10 ^−1.5 bit error rate (BER) compared with the traditional uniformly-distributed 32-CAP. The experiment suggests the proposed scheme a promising technique for future optical interconnects.