信号在光纤中的传输受到克尔非线性损伤的影响,产生非线性的频谱展宽效应,导致信息泄漏到带外、接收端的带内信息不完整。传统的非线性补偿方法通过反转信道传输函数在接收端对信号进行处理,效果不理想。针对该问题,首先,通过优化算法寻找在数字反向信道传输时可利用克尔非线性将原始信号压缩至另一奈奎斯特带宽的带外伴随信号;然后,将压缩后的奈奎斯特信号在发射端发送;最后,在接收端通过奈奎斯特滤波恢复原始信号。仿真结果表明,本算法在带限系统中的性能优于反向传输方法,在长度为800 km的标准单模光纤中的误差向量幅度增益为3.17 dB。

The transmission of signal in optical fiber is affected by Kerr nonlinear damage, resulting in nonlinear spectrum broadening effect, resulting in information leakage out of band and incomplete information in the receiving end. The traditional nonlinear compensation method processes the signal at the receiving end by inverting the channel transfer function, but the effect is not ideal. In order to solve this problem, first, the optimization algorithm is used to find out the out of band adjoint signal which can compress the original signal to another Nyquist bandwidth in the digital reverse channel transmission; Second, the compressed Nyquist signal is sent in the sender; Finally, the original signal is recovered by Nyquist filtering at the receiving end. Simulation results show that the performance of the proposed algorithm is better than that of reverse transmission method in the band-limited systems, and the gain of the error vector amplitude is 3.17 dB in the standard single-mode fiber with the length of 800 km.