High Spectral Efficiency WDM Transmission Based on Hybrid Probabilistically and Geometrically Shaped 256QAM
High Spectral Efficiency WDM Transmission Based on Hybrid Probabilistically and Geometrically Shaped 256QAM
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基于混合概率和几何形状 256QAM 的高频谱效率 WDM 传输
DOI：
10.1109/jlt.2021.3087919
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发表时间：
2021-06
影响因子：
4.7
通讯作者：
Jianjun Yu
中科院分区：
文献类型：
--
作者：
Junjie Ding;bohan Sang;Yanyi Wang;Miao Kong;Feng Wang;BoWen Zhu;Li Zhao;Wen Zhou;Jianjun Yu
实验证明，在400 km标准单模光纤（SSMF）上传输10路50 GHz网格波分复用（WDM）信号，净比特率为614.4 Gbps/载波，频谱效率（SE）为12.288 B/s/Hz，是目前已知的256 QAM中最高的SE。由于联合预均衡和沃尔泰拉非线性均衡（VNLE），使用概率成形（PS）和几何成形（GS）技术实现了具有新颖星座的49-Gbaud偏振分复用（PDM）256进制正交幅度调制（256 QAM）信号传输，考虑0.828归一化广义互信息（NGMI）低密度奇偶校验（LDPC）阈值，开销为25%。与相同净比特率的常规256 QAM相比，所设计的PS/GS混合256 QAM在单信道和WDM情况下，以符号速率增加1-Gbaud为代价，分别获得了1.7-dB和1.5-dB的整形增益。同时，与用于单信道和WDM传输的PS-256 QAM相比，实现了混合PS/GS 256 QAM的光信噪比（OSNR）的至少0.6-dB的改进。
We experimentally demonstrated a 10-channel 50-GHz-grid wavelength division multiplexing (WDM) signal transmission over 400-km standard single-mode fiber (SSMF) with the net bit rate of 614.4 Gbps/carrier and the spectral efficiency (SE) of 12.288 b/s/Hz, which is the highest SE for 256QAM to the best of our knowledge. Thanks to the joint pre-equalization and Volterra nonlinear equalization (VNLE), 49-Gbaud polarization division multiplexing (PDM) 256-ary quadrature amplitude modulation (256QAM) signal transmission with a novel constellation using probabilistic shaping (PS) and geometric shaping (GS) techniques is realized, considering the 0.828-normalized generalized mutual information (NGMI) low-density parity-check (LDPC) threshold with 25% overhead. Compared with the regular 256QAM at the same net bit rate, the designed hybrid PS/GS 256QAM at the expense of 1-Gbaud increase in the symbol rate obtains 1.7-dB and 1.5-dB shaping gain in single-channel case and WDM case, respectively. Meanwhile, an improvement of at least 0.6-dB in optical signal to noise ratio (OSNR) over the hybrid PS/GS 256QAM is achieved in comparison with PS-256QAM for both single-channel and WDM transmission.