A Modif ied Adaptive DBP for DP 16 QAM Coherent Optical System
A modified adaptive digital backpropagation (A DBP) algorithm based on intensity variance is proposed in this letter. In the simulation, a 25 GBd dual polarization 16 quadrature amplitude modulation transmission system with a transmission distance of 2000 km is established to investigate the performance of the proposed A DBP. The simulation results show that the proposed A DBP can dynamically estimate the optimal fiber nonlinear coefficient gopt and achieve comparable or even better performance than the DBP with full knowledge of fiber. Moreover, the proposed A DBP can achieve better performance compared with the previous A DBP based on intensity variance. Moreover, the proposed A DBP requires fewer iterations to determine gopt compared with the previous A DBP based on intensity or phase variance.
IEEE Photonics Technology Letters