Digital back propagation based on the feedback-convergence for fiber nonlinearity compensation with low computational complexity and high performance

In this paper, an improved digital back propagation (DBP) method is proposed for the compensation of fiber non-linearity, which is based on the feedback-convergence assisted split-step Fourier method. The algorithm has been experimentally verified in a 1000 km 80 Gbit/s PDM-16QAM system. By optimizing the structure of nonlinear convergence within the DBP method, the accuracy of nonlinear compensation is improved comparing with the traditional algorithms while complexity reduced. The results show that the OSNR penalty for BER of HD-FEC threshold has reduced by 1.1 dB, and the transmission distance can be increased by ∼155 km for the threshold value of BER=1×10⁻⁴ compared to the traditional DBP method. When OSNR = 26 dB, the complexity of FC-DBP decreases 36.91% comparing with the traditional DBP method.