采用数值模拟的方法, 研究了周期性光谱调制对飞秒脉冲自相似放大的影响。构建了叠加光谱调制的飞秒脉冲自相似放大的理论模型, 分析任意相移量、调制深度和调制周期等参量变化对自相似放大系统的影响。结果表明, 任意相移量虽然会改变被调制后光谱具体形状, 但不会影响自相似放大的时域结果; 调制周期较大时, 子脉冲和主脉冲重叠, 对自相似放大过程和结果造成一定程度的破坏; 调制周期较小时, 主脉冲独立放大, 基本不会被子脉冲影响, 这一结论在调制深度改变时依然成立。

The effects of periodic spectral modulation on self-similar amplification systems of femtosecond pulses were studied by numerical simulation. Femtosecond pulses with spectral modulation amplified in self-similar amplification theoretical model were simulated, by which the impacts of variables of seed pulses, such as arbitrary phase shift, modulation depth and period, on output results were analyzed. According to the simulation, arbitrary phase shift changes modulated spectral shape, but temporal results of self-similar amplification will not be affected. Besides, large modulation periods make sub-pulses inseparable from main-pulses, disturbing the self-similar amplification process, while small modulation periods bring a longer delay for sub-pulses, making the amplification of main- and sub-pulse independently. This conclusion is still tenable when modulation depth changes.