Optimization of All-Optical 2R Regenerators Operating at 40 Gb/s: Role of Dispersion

We investigate numerically the interplay between dispersion and nonlinearity for optimizing the performance of an all-optical 2R regenerator based on self-phase modulation and spectral filtering at 40 Gb/s. By considering the extent of improvement in the Q factor (related to level of noise reduction), we show that the ratio of accumulated dispersion to the maximum nonlinear phase shift can be used to predict the performance of regenerators making use of fibers with very different lengths, dispersions, and nonlinear parameters. Our results show that fiber dispersion plays an important role and needs to be properly optimized. In general, fibers with larger dispersion perform better but require higher input powers. We also study the impact of fluctuations in dispersion from their nominal value and show that their impact is much less severe when fiber dispersion is relatively small.