Fig. 7. The 16QAM constellation diagrams after 2400 km transmission using the BLSS DBP technique with: (a) 1 step/span; (b) 2 steps/span; (c) 6 steps/span; (d) and 10 steps/span
CONCLUSION
A binary logarithmic step size optimization technique of the SSFM has been presented to effectively implement the DBP technique for fiber impairment compensation with low complexity. Optimum step sizes are generated using a binary step size distribution for accurate DBP calculation. The numerical results indicate that step size optimization using the binary logarithmic step size distribution brings significant improvement benefits over the conventional logarithmic and constant step size distribution techniques and extends the possible transmission distance over several kilometers. A high performance (Q) of 10.9 dB (BER = 2.25×10-4) is achieved at the HD-FEC limit. The proposed technique can achieve optimum nonlinearity compensation with only 10 steps, whereas the conventional DBP requires 16 steps for optimum performance. Thus, the optimization achieves 38% savings in the number of DBP calculation steps over the constant step size DBP, reducing the computational cost since a few steps are required to mitigate nonlinear distortions effectively. The proposed BLSS is, therefore, a promising technique for high accuracy and low complexity DBP implementation for compensating distortions in high data rate optical transmissions.