掺镱光纤放大器中脉冲自相似演化特性分析

摘要

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 Schrodinger 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.%为了研究自相似演化对于高功率超短脉冲系统产生的影响,采用非线性薛定谔方程,对掺镱光纤放大器中自相似解进行了理论分析,得到初始脉冲、脉冲宽度、增益系数、增益色散等参量变化时对其自相似演化产生不同的影响.结果表明,初始脉宽不同时,只有其初始色散长度和光纤长度相接近时,才可以实现脉冲自相似的演化;初始输入脉冲不同时均能演化成抛物线形,但是演化的进程不同;大的增益系数可以获得高功率、宽频谱的自相似脉冲;增益色散对自相似放大起滤波作用.研究结果对设计自相似脉冲放大器具有一定的借鉴价值.