Pulse propagation in nonlinear-optical fibers with phase-locked phase-sensitive amplifiers

Recently the use of periodically spaced, phase-sensitive optical parametric amplifiers was proposed for compensating for linear loss in a nonlinear fiber-optic communication line [Opt. Lett. 18, 803 (1993)]. In the previous analysis, in which the stability of a single pulse was investigated, the variation of the amplifier phases was neglected. In a physically realizable line, however, the phase of each amplifier would most likely be locked to the phase of the signal pulse or to the average of the phases of many such pulses. Here an analysis is presented in which the amplifier phase is allowed to vary in response to a signal pulse's optical phase. The analysis shows that the solitonlike signal pulses remain stable even with this additional phase variation.