Three-dimensional constellation design based on centroid-corrected geometric shaping with optimized average Hamming distance
Wang Chen, Bo Liu, Jianxin Ren, Yaya Mao, xiumin song, Shuaidong Chen, Jianye Zhao, Yu Bai, Haojun Liu, Yongyi Yu, Chuanxi Zhang, Rahat Ullah · Optics Express · 2025
In this paper, a novel (to our knowledge) three-dimensional (3D) constellation design based on centroid-corrected geometric shaping (CCGS) with optimized average Hamming distance (OAHD) is proposed, referred to as 3D-CCGS-OAHD. This scheme employs a centroid-correction technique to optimize the constellation point distribution and ensure a balanced geometry for higher constellation figure of merit (CFM). Meanwhile, a simulated annealing (SA) algorithm is used to minimize the average Hamming distance (AHD) between adjacent constellation points and explore a better bit-to-symbol mapping strategy superior to Gray mapping to improve the bit error rate (BER) performance. The 3D-CCGS-OAHD scheme was successfully demonstrated over a 2 km 7-core fiber. Results show that the 3D-CCGS constellation achieves a sensitivity gain of 0.84 dB compared to the traditional 3D constellation under Gray mapping. In addition, the 3D-CCGS-OAHD scheme achieves a gain of 1.29 dB compared to the traditional 3D constellation. The experiment results demonstrate that the proposed scheme is suitable for short-distance optical communication systems and has promising research prospects.