Abstract

A low-complexity scheme is proposed to realize irregular uniform quadrature amplitude modulation (QAM) formats with Gray mapping, which are named amplitude-division irregular QAM (AD-Ir-QAM) formats. Compared to conventional probabilistic shaping (PS) with the Maxwell–Boltzmann (MB) distribution (PS-MB), irregular QAM formats show a smaller peak-to-average power (PAPR) and achieve a better performance in systems with the peak-power constraint. Compared with irregular QAM formats realized by PS (PS-Ir-QAM), AD-Ir-QAM formats realize a more flexible rate adaptation and have a lower implementation complexity. Experimental results obtained in an unamplified coherent optical system show that, at a generalized mutual information (GMI) of 4.5 bits/2D-symbol, AD-Ir-100QAM achieves gains of 2.1 and 0.5 dB in the power budget over PS-MB-100QAM and PS-Ir-100QAM, respectively.

© 2023 Optica Publishing Group

Low complexity joint clock recovery and adaptive equalization based on a baud-rate timing phase error detector for short-reach digital coherent transmission

Jingpeng Liu, Chengbo Li, Sheng Cui, Yanan Chen, Jianwei Tang, Jinhao Zhou, Keji Zhou, Jing Dai, and Ming Tang
Opt. Lett. 48(16) 4384-4387 (2023)

Carrier phase recovery friendly probabilistic shaping scheme based on a quasi-Maxwell–Boltzmann distribution model

Xishuo Wang, Qi Zhang, Jianjun Yu, Xiangjun Xin, Kai Lv, Ran Gao, Jianxin Ren, Feng Tian, Qinghua Tian, Chuxuan Wang, Xiaolong Pan, Yongjun Wang, Dong Guo, and Leijing Yang
Opt. Lett. 45(17) 4883-4886 (2020)

Adaptive feedback-driven probabilistic shaping for high-order modulation formats in a fiber–THz seamless integration system at 320 GHz

Xiang Liu, Jiao Zhang, Min Zhu, Junhao Zhang, Weidong Tong, Zhigang Xin, Bingchang Hua, Yuancheng Cai, Mingzheng Lei, Bo Liu, and Jianjun Yu
Opt. Lett. 48(24) 6557-6560 (2023)

Optimized pilot structure for PS-PDM ultrahigh-order QAM coherent optical transmission

Xin Shi, Mingyi Gao, Xuejing Huang, Jiamin Fan, Xinbang Han, Xiaodi You, and Gangxiang Shen
Opt. Lett. 49(6) 1579-1582 (2024)

Principle and strategy of using probabilistic shaping in a flexible coherent passive optical network without optical amplifiers

Sizhe Xing, Guoqiang Li, An Yan, Wangwei Shen, Zhongya Li, Jiaye Wang, Jianyang Shi, Zhixue He, Nan Chi, and Junwen Zhang
J. Opt. Commun. Netw. 15(8) 507-517 (2023)