  Stochastic power fluctuation in a fiber optic system due to the interplay
among dispersion, nonlinearity and partial coherence of the source is
investigated. An analytical expression for the power fluctuation of a signal
pulse due to its interference with an echo pulse generated due to the nonlinear
interaction of signal pulses in a fiber optic system excited by a partially
coherent source is obtained. The analytical results show that the mean
nonlinear distortion decreases as the coherence time of the source reduces
consistent with our numerical simulations.
