Yang Zheng, Fu Songnian, Tang Ming, Wang Yuncai, Qin Yuwen
Opt Lett. 2021 Apr 1;46(7):1680-1683. doi: 10.1364/OL.421467.
Volterra filter equalizer (VFE) is a commonly-used nonlinear equalizer (NLE) to effectively mitigate both linear and nonlinear impairments arising in intensity-modulation direct-detection (IM-DD) transmission. However, the high calculation complexity of VFE becomes the bottleneck for the high-speed long-reach IM-DD transceiver. To achieve the hardware-efficient NLE, we propose an optimized VFE based on the weighted principal component analysis (WPCA), which uses both supervised weights and unsupervised PCA to extract principal components, so that the number of VFE taps can be significantly reduced without transmission penalty. It is experimentally verified that the proposed method can reduce 40% and 60% taps of traditional VFE, respectively, for C-band 80 Gb/s four-level pulse amplitude modulation (PAM-4) transmission over 20 km chromatic dispersion (CD)-uncompensated standard single-mode fiber (SSMF) and 56 Gb/s PAM-4 transmission over 100 km CD-managed SSMF.
伏尔特拉滤波器均衡器（VFE）是一种常用的非线性均衡器（NLE），用于有效减轻强度调制直接检测（IM-DD）传输中出现的线性和非线性损伤。然而，VFE的高计算复杂度成为高速长距离IM-DD收发器的瓶颈。为了实现硬件高效的NLE，我们提出了一种基于加权主成分分析（WPCA）的优化VFE，它使用监督权重和无监督主成分分析来提取主成分，从而可以在不造成传输代价的情况下显著减少VFE抽头的数量。实验验证，对于在20公里无色散补偿标准单模光纤（SSMF）上进行的C波段80 Gb/s四电平脉冲幅度调制（PAM-4）传输以及在100公里色散管理SSMF上进行的56 Gb/s PAM-4传输，所提方法分别可以减少传统VFE 40%和60%的抽头。
