中文摘要：

从光纤广义非线性薛定谔方程出发，定义了用于衡量脉冲形变大小的脉冲形变因子，定量地分析了在传输过程中脉冲形变因子、临界长度、临界功率及初始啁啾之间的关系。结果表明：在传输过程中，当入射脉冲的峰值功率一定时，正啁啾脉冲的形变比负啁啾脉冲和无啁啾脉冲的形变小；当脉冲的初始啁啾一定时，脉冲传输的临界长度随着传输功率的增加而降低，且随着功率的增大，不同初始啁啾脉冲的临界长度趋于一致；在传输距离一定时，临界功率与初始啁啾呈线性变化，且啁啾的漂移对正啁啾脉冲的临界功率影响较大。

英文摘要：

Based on nonlinear Schr5dinger equation in optical fiber, the factor of distortion of pulse （DIS） is defined to evaluate the distortion of the pulse. The relation amongthe DIS, critical length of propagation, critical power and initial chirp of the pulse are numerically simulated and analyzed when only dispersion and self-phase modulation are considered. The results show that the distortion of positive chirped pulse is less than that of negative chirped pulse for given peak power. For given initial chirp, the critical length of pulse decreases with increasing of peak power of input pulse, and critical length of different initial chirp ~t pulses coincides along with increasing of peak power of input pulse. When the length of propagation is fixed, critical power is linear with initial chirp, meanwhile the fluctuation of chirp have more effect on the positive chirped pulse.