在北京大学200 TW激光系统上，测量了经可编程声光色散滤波器不同程度光谱调制后放大器输出脉冲的频域分布，并设计了一个与脉冲中心波长、光谱宽度等参数相关的光谱调制函数拟合了实验测得的光谱数据。该函数形式简单，适用于不同的激光系统。对实验系统中种子脉冲经光谱调制后从放大器输出的光谱结果进行了数值模拟，对比研究了普通种子脉冲和光谱调制脉冲经放大器增益后时域空间内的物理性质；讨论了光谱调制对系统最终输出脉冲峰值功率的影响。结果表明：光谱调制会导致脉冲旁瓣的产生，降低系统输出脉冲的有效能量和飞秒对比度，系统输出脉冲为平顶光谱时，其有效输出峰值功率最大。

The frequency domain distribution of amplified pulse modulated by the acousto-optic programmable dispersive filter is measured on the 200 TW laser system in Peking University. A spectral modulation function related to the pulse central wavelength and spectral bandwidth is established to fit the measured spectral data. The function is simple and suitable for different laser systems. Based on the numerical simulation of the amplifier output pulse′s spectra after the seed pulse modulation, the time-domain characteristics of the ordinary seed pulse and the spectrum modulated pulse through the amplifier are compared. The effects of spectral modulation on the peak power of the final output pulse are discussed. The result shows that the spectral modulation can lead to the generation of sidelobes and reduce the effective energy and femtosecond contrast of the system output pulse. When the output pulse has a flat-top spectrum, its effective peak power is the largest.