We have investigated the stabilizing effect of nonlinear gains on soli
ton transmission, making use of a modified nonlinear Schrodinger equat
ion representing a system with nonlinear gain, and solving the equatio
n numerically using the Fourier series analysis technique. We have fou
nd that in the presence of second- and fourth-order nonlinearities, a
relatively high stability can be achieved in soliton transmission. (C)
1998 John Wiley & Sons, Inc.