从理论上分析了非线性折射率引起的脉冲自位相调制对超短脉冲的影响。提出用时间域滤波改善飞秒激光脉冲质量。针对这一新的方法进行了数值模拟分析。研究结果表明时间域滤波可使系统输出脉冲变窄，并提高了脉冲峰值功率，有效地提高了脉冲的质量。

The article theoretically analyzes the impact of self phase modulation caused by nonlinear refractive index on ultrashort pulse. A new method, temporal filtering, is proposed for improving quality of femtosecond laser pulse. After analyzing the result of simulation, it is found that the filter method can narrow pulse and enhance the intensity of pulse. The approach can improve the quality of femtosecond pulse.