Solitary waves in a single-mode fiber with two-photon absorption and bandwidth-limited optical gain.
The exact soliton solutions of the nonlinear Schrödinger equation and the extended nonlinear Schrödinger equation with two-photon absorption and bandwidth-limited optical gain, respectively, are given. The results show that both picosecond and femtosecond soliton pulses can be propagated in a single-mode fiber with twophoton absorption and symmetric optical gain with the proper spectral profile.