Stimulated Brillouin Scattering In Fiber Slow Light Pulse Distortion Management Studies

Slow-light techniques in optical fibers based on nonlinear effects are promising for obtaining tunable and controllable delay lines which are potential candidates for optical buffers, data synchronization, optical memories, and signal processing. We mostly investigate the methodology to realize the broadband stimulated Brillouin scattering (SBS) slow light in a single-mode optical fiber (SMF) for optimizing the delay of signal pulse under the pulse distortion-constraints. We adopt the single or double, line or broadband pump schemes. The main achievements are listed below:Taking into account the allowable pulse distortions in real applications, we describe a methodology to realize optimization and management of the single pulse distortion by optimizing physical variables. We discuss the dependence of amplitude distortion, phase distortion and pulse broadening on group delay of single pulse. Under allowable pulse distortion, we compare the optimized results of the group delay of signal pulse between pumping with single line and that with double lines. As an example, given the allowable amplitude and phase distortions we find the group delay using doublet pump is 2 times of that using single pump; while given the allowable phase distortion and pulse broadening it is found that the group delay using doublet pump can be 5.7 times of that using single pump.We propose a new method of realizing the broadband SBS slow light using a double broadband pump scheme in SMF. Theoretical model of this double broadband pump SBS slow light and its pulse broadening effect are presented. Dispersion analyses indicate that there exists an optimum spectral separation between the central frequencies of the double pump beams, which makes it possible to effectively reduce the signal pulse broadening related to the group velocity dispersion. Theoretical calculations show that the SBS gain bandwidth and the signal pulse's group delay using this scheme can enhance to 1.7 and 2 times of that using just one single broadband laser respectively. SBS bandwidth of 13.8GHz is obtained. This method provides a theoretical guide for controllable optical delay of 10Gbits/s signal pulse.