We experimentally demonstrated a photoelectric nonlinear compensation scheme of optical phase conjugation (OPC) with complex-valued deep neural network (CVDNN) to mitigate fiber nonlinearity in wavelength division multiplexing (WDM) 64-QAM coherent optical transmission system. The factors to affect the performance of OPC and CVDNN are comprehensively considered. OPC in WDM system is experimentally optimized to alleviate the deployment requirements of strict symmetrical distributed power and chromatic dispersion. The performance penalty caused by the simplification of the OPC is further compensated by the CVDNN. The selections of the input neurons’ number and the optimization algorithm are also considered to design a simple two-hidden-layer-structure CVDNN. The proposed method is experimentally verified and evaluated in a 12.5-GBd 4-channel WDM 64-QAM 160-km standard single-mode fiber (SSMF) transmission system with channel spacing of 50-GHz. The experimental results show that the proposed nonlinear equalizer based on the OPC with CDVNN has a strong robustness to the input signal power and wavelength, which can not only improve the Q factor of the signal by 1.5-dB, but also greatly increase the total launched signal power.

中文翻译：

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用于 WDM 64-QAM 相干光学系统的复值深度神经网络的光相位共轭

我们通过实验证明了具有复值深度神经网络 (CVDNN) 的光学相位共轭 (OPC) 的光电非线性补偿方案，以减轻波分复用 (WDM) 64-QAM 相干光传输系统中的光纤非线性。综合考虑影响OPC和CVDNN性能的因素。WDM系统中的OPC经过实验优化，以减轻严格对称分布功率和色散的部署要求。简化 OPC 造成的性能损失由 CVDNN 进一步补偿。还考虑了输入神经元数量的选择和优化算法来设计一个简单的两隐藏层结构的 CVDNN。所提出的方法在 12 中经过实验验证和评估。5-GBd 4 信道 WDM 64-QAM 160 公里标准单模光纤 (SSMF) 传输系统，信道间隔为 50-GHz。实验结果表明，所提出的基于 OPC 和 CDVNN 的非线性均衡器对输入信号功率和波长具有很强的鲁棒性，不仅可以将信号的 Q 因子提高 1.5 dB，而且还大大增加了发射的总发射功率。信号功率。