Digital Backpropagation Based on Binary Logarithmic Step Size Distribution for Fiber Nonlinearity Compensation

Capacity crunch has become critical in recent years as commercial communication systems approach their theoretical data rate limits. This work presents a low-complexity digital backpropagation (DBP) implementation approach based on step size distribution that uses a binary logarithmic step size method to achieve high data rate optical transmission. The proposed scheme shows performance improvements (∆Q) of 2.36 dB, 1.19 dB, and 0.71 dB over linear compensation, constant step size DBP, and logarithmic step size DBP techniques in a 2400 km 112 Gbit/s DP-16QAM system, respectively. At 13 dBm, a high performance (Q) of 10.9 dB (BER = 2.25×10-4) is achieved, above the 3.80×10-3 hard-decision forward error correction (HD-FEC) limit, using the proposed scheme. Also, the allowable transmission distance is extended by 960 km at the HD-FEC limit over the linear compensation technique. The optimization achieves a 38% savings in the number of DBP calculation steps compared to the constant step size DBP, which considerably reduces the computational cost since a few steps are required for effective nonlinearity compensation.