Zhou Ji, Wang Haide, Liu Long, Yu Changyuan, Feng Yuanhua, Gao Shecheng, Liu Weiping, Li Zhaohui
Opt Lett. 2020 Feb 1;45(3):758-761. doi: 10.1364/OL.384168.
In this Letter, we present a record C-band 56 Gbit/s intensity-modulation/direct-detection optical on/off keying (OOK) system over a 100 km dispersion-uncompensated link using only the receiver-side digital signal processing (DSP). The proposed DSP mainly includes an adaptive moment estimation (Adam)-based polynomial nonlinear equalizer (PNLE), autoregression (AR)-based post filter, and maximum likelihood sequence estimation (MLSE). Due to square-law detection, chromatic dispersion induces 11 nulls on the 28 GHz spectrum of the 56 Gbit/s OOK signal after the 100 km standard-single-mode-fiber transmission. Adam-based PNLE eliminates major linear and nonlinear distortions, but it cannot compensate the nulls. After the Adam-based PNLE, the AR-based post filter and MLSE further deal with the inter-symbol interference caused by the nulls to improve the system performance. The proposed C-band 56 Gbit/s OOK system shows great potential for future metro networks and data center networks.
在本信函中，我们展示了一种创纪录的C波段56 Gbit/s强度调制/直接检测光开关键控（OOK）系统，该系统在100 km无色散补偿链路中仅使用接收端数字信号处理（DSP）。所提出的DSP主要包括基于自适应矩估计（Adam）的多项式非线性均衡器（PNLE）、基于自回归（AR）的后置滤波器以及最大似然序列估计（MLSE）。由于平方律检测，在经过100 km标准单模光纤传输后，色散在56 Gbit/s OOK信号的28 GHz频谱上产生了11个零点。基于Adam的PNLE消除了主要的线性和非线性失真，但无法补偿这些零点。在基于Adam的PNLE之后，基于AR的后置滤波器和MLSE进一步处理由零点引起的码间干扰，以提高系统性能。所提出的C波段56 Gbit/s OOK系统在未来城域网和数据中心网络中显示出巨大潜力。
