Self-similar pulse evolution in ytterbium doped fiber amplifiers

In order to study the evolvement and transmission of a self-similar pulse in a high power ultra-short pulse generation system,the self-similar solutions of the nonlinear Schrdinger equation in ytterbium doped fiber amplifiers were analyzed theoretically.The influence of the initial pulse shape,the initial pulse width as well as gain coefficient and gain dispersion on the pulse self-similar evolution were numerically studied.It is shown that when the dispersion length is close to fiber length,the initial pulse can evolve into a parabolic pulse.Different kinds of initial pulses are all evolved into parabolic profiles with different evolutionary process.Larger gain coefficient is beneficial to generate self-similar parabolic pulse with high power and wide frequency range.The gain dispersion plays an important role in frequency filtering.