Propagation and breakup of pulses in fiber amplifiers and dispersion-decreasing fiberswith third-order dispersion

摘要

We develop a theory for pulses propagating in normal dispersion fiber amplifiers with constant and varying gain, and for dispersion-decreasing fibers, including the effect of third-order dispersion. These solutions of the generalized nonlinear Schrodinger equation are based on asymptotical methods, first-order perturbation theory, and a renormalization procedure. We have also found an explicit equation for the critical length corresponding to pulse breakup and a criterion which ensure the accuracy of the asymptotic solutions. This criterion is confirmed numerically, showing that the analytical description of the pulses and the critical length formulas developed here for fiber amplifiers and dispersion-decreasing fibers with third-order dispersion are very accurate.