Evolution of chirped pulses in nonlinear single-mode fibers

Computer studies of the evolution of pulses in nonlinear single-mode fibers are presented. In the case of anomalous dispersion, the time-bandwidth product of the initial pulse is varied by imposing a linear frequency chirp. The pulse broadening resulting from chirp greatly exceeds the broadening caused by the loss. In the case of normal dispersion the evolution of an initially unchirped pulse is shown to depend critically on the loss. This fact is explained by the position of the chirp's maxima and minima relative to the pulse-amplitude distribution.