Abstract
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.