基于高功率激光系统前端全光纤脉冲整形系统输出的脉冲特性，以两路脉冲堆积为例，理论分析并讨论了光纤中群速度色散的作用，提出了分离距离的概念，得出了整形脉冲时间调制周期、瞬时频率，以及初始啁啾对脉冲波形影响的解析结果。数值模拟了脉冲波形、瞬时频率在正、负色散光纤中随时间的变化特性，以及时间调制周期与传输距离之间的关系。结果表明，堆积脉冲不同位置瞬时频率变化不同；脉冲时间调制周期与时延和初始啁啾以及色散符号有关。

Based on the output pulse characteristics of all-fiber pulse shaping system, taking example for the two pulses stacking, the effects of group-velocity dispersion are analyzed and discussed, and the walk-off distance concept is provided. The analytic results are achieved about the temporal modulation period, instantaneous frequency and the effects of initial chirp on the pulse. The numerical simulations are presented on the change characteristics of the pulse shape, instantaneous frequency with the time in the positive, negative dispersion fiber respectively, and the relationship between the modulation period and the transmission distance. As a result, the instantaneous frequency is different at different position. With the transmission, the period increases in the positive dispersion fiber, while in the negative, it decreases, except that at the walk-off point, the period changes rapidly.