Self-similar propagation of high-power parabolic pulses in optical fiber amplifiers

Self-similarity techniques are used to study pulse propagation in a normal- dispersion optical fiber amplifier with an arbitrary longitudinal gain prof ile. Analysis of the nonlinear Schrodinger equation that describes such an amplifier leads to an exact solution in the high-power limit that correspon ds to a linearly chirped parabolic pulse. The self-similar scaling of the p ropagating pulse in the amplifier is found to be determined by the function al form of the gain profile, and the solution is confirmed by numerical sim ulations. The implications for achieving chirp-free pulses after compressio n of the amplifier output are discussed. (C) 2000 Optical Society of Americ a.