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.