Abstract

Unlike the scenario in traditional high-order QAM signals, Viterbi and Viterbi (V&V) algorithm becomes more powerful for carrier phase recovery (CPR) in probabilistically shaped (PS) signals. The reason relies on that the PS signals assign much higher probability to the innermost 4 constellation points, which are qualified for V&V algorithm. In this article, we compare the performance of V&V algorithm to that of blind phase search (BPS) algorithm for PS-64 QAM and PS-256 QAM in the aspects of window size and signal to noise ratio under the constraint of different laser linewidths. Besides, the impact of signal entropy on both algorithms is investigated. The computational complexity and running time for both algorithms are also summarized. Results show that the two algorithms perform similarly for PS-64 QAM signals when the linewidth is less than 1 MHz while the running time of BPS algorithm is at least 45 times longer than that of V&V algorithm. Finally, we conduct a coherent detection based optical back-to-back experiment where the laser linewidths of both transmitter laser and local oscillator are 100 kHz. For PS-64 QAM, both V&V and BPS algorithms show negligible penalty compared to the performance of homodyne detection, verifying the feasibility of applying V&V algorithm in the CPR of PS-64 QAM.

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)

Maximum probability directed blind phase search for PS-QAM with variable shaping factors

Zexin Chen, Songnian Fu, Ming Tang, Zhenrong Zhang, and Yuwen Qin
Opt. Express 30(1) 550-562 (2022)

Degenerated look-up table–based perturbative fiber nonlinearity compensation algorithm for probabilistically shaped signals

Yiwen Wu, Huazhi Lun, Mengfan Fu, Xiaobo Zeng, Xiaomin Liu, Qiaoya Liu, Lilin Yi, Weisheng Hu, and Qunbi Zhuge
Opt. Express 28(9) 13401-13413 (2020)

Hardware optimization of dual-stage carrier-phase recovery for coherent optical receivers

Celestino S. Martins, Fernando P. Guiomar, and Armando N. Pinto
OSA Continuum 4(12) 3157-3175 (2021)

Pilot-aided carrier phase recovery for M-QAM using superscalar parallelization based PLL

Qunbi Zhuge, Mohamed Morsy-Osman, Xian Xu, Mohammad E. Mousa-Pasandi, Mathieu Chagnon, Ziad A. El-Sahn, and David V. Plant
Opt. Express 20(17) 19599-19609 (2012)