Digital backpropagation based on binary logarithmic step size distribution for fibre non-linearity compensation

Capacity crunch has become critical in recent years as commercial communication sys-tems approach their theoretical data rate limits. This work presents a low-complexity digitalbackpropagation (DBP) implementation approach based on step size distribution that usesa binary logarithmic step size method to achieve high data rate optical transmission. Theproposed scheme shows performance improvements (∆Q) of 2.36, 1.19, and 0.71 dBover linear compensation, constant step size (CSS) DBP, and logarithmic step size DBPtechniques in a 2400 km 112 Gbit/s DP-16 quadrature amplitude modulation (QAM) sys-tem, respectively. At 13 dBm, a high performance (Q) of 10.9 dB (BER=2.25×10−4)is achieved, above the 3.80×10−3hard-decision forward error correction (HD-FEC)limit, using the proposed scheme. Also, the allowable transmission distance is extendedby 960 km at the HD-FEC limit over the linear compensation technique. The optimiza-tion achieves a 38% saving in the number of DBP calculation steps compared to the CSSDBP, which considerably reduces the computational cost since a few steps are required foreffective non-linearity compensation.