THE EFFECT OF PULSE WALKOFF ON THE COMPRESSION OF BRIGHT OPTICAL PULSES BY DARK SOLITONS

The effect of pulse walkoff on the compression of bright optical pulse s by dark solitons in single-mode fibers is analyzed by numerically so lving the coupled amplitude equations describing the evolution of two copropagating pulses. The results show that even a small walkoff betwe en the bright pulse and the dark soliton can exert a severe influence on the bright pulse compression. The compressed bright pulse is longer with a lower peak power when walkoff is taken into account. Furthermo re, the compressed bright pulse is asymmetric and the optimum fiber le ngth is found to be longer than that expected in the absence of pulse walkoff. It is suggested that the bright pulse and the dark soliton sh ould be coupled asynchronously at the input end of the fiber, and resu lts show that asynchronous coupling of the two pulses can improve the bright pulse compression as compared with the synchronous coupling sch eme.