Tu Yucheng, Yang Hailin, Zhou Gai, Xiang Meng, Fu Songnian, Tang Ming, Qin Yuwen, Zhao Luming
Opt Express. 2022 Apr 25;30(9):15416-15427. doi: 10.1364/OE.457629.
The performance of high baud-rate intensity modulation direct detection (IM-DD) transmissions is severely degraded by both the linear and nonlinear inter-symbol interference (ISI). Here, we propose and experimentally demonstrate a transmitter-side look-up-table pre-distortion combined with nonlinear Tomlinson-Harashima pre-coding (LUT_PD-NTHP) scheme with the capability of mitigating the linear and nonlinear ISI simultaneously, enabling a C-band 200 Gbit/s/λ PAM-4 transmission over 2-km standard single mode fiber (SSMF), under an end-to-end 10-dB bandwidth of about 20 GHz. The proposed LUT_PD-NTHP scheme is experimentally verified to be superior to the LUT pre-distortion combined with linear THP (LUT_PD-LTHP) scheme, in terms of both the receiver sensitivity and the LUT storage requirement, when only the feed-forward equalization (FFE) is used at the receiver-side. In particular, after the 200 Gbit/s PAM-4 signal transmission over the 2-km SSMF without the chromatic dispersion (CD) compensation, the proposed LUT_PD-NTHP scheme with a LUT pattern length of 3 possesses not only 0.25 dB improvement of the receiver sensitivity but also about 99% LUT pattern reduction, in comparison with the LUT_PD-LTHP scheme with a LUT pattern length of 5.
高波特率强度调制直接检测（IM-DD）传输的性能会因线性和非线性符号间干扰（ISI）而严重下降。在此，我们提出并通过实验证明了一种发射机端查找表预失真与非线性汤姆林森-哈拉希玛预编码（LUT_PD-NTHP）相结合的方案，该方案能够同时减轻线性和非线性ISI，在约20 GHz的端到端10 dB带宽下，实现了在2公里标准单模光纤（SSMF）上的C波段200 Gbit/s/λ PAM-4传输。实验验证，当在接收机端仅使用前馈均衡（FFE）时，所提出的LUT_PD-NTHP方案在接收机灵敏度和LUT存储要求方面均优于查找表预失真与线性THP（LUT_PD-LTHP）相结合的方案。特别是，在2公里SSMF上进行200 Gbit/s PAM-4信号传输且无色散（CD）补偿后，与LUT模式长度为5的LUT_PD-LTHP方案相比，所提出的LUT模式长度为3的LUT_PD-NTHP方案不仅接收机灵敏度提高了0.25 dB，而且LUT模式减少了约99%。
