基于光纤中的耦合波方程和琼斯矩阵建立了非线性偏振旋转锁模光纤激光器的数值模型，模拟研究了抽运激光功率抖动和腔长抖动对锁模激光器输出脉冲幅值抖动的影响。结果表明，抽运激光功率Pp的抖动对锁模激光器脉冲幅值抖动影响较大，幅值抖动随着Pp抖动的增大而增大，当抽运功率有±3%的随机抖动时，锁模脉冲幅值的均方根(RMS)值达到0.82%，峰谷(P-V)值达到2.84%；而腔长抖动对脉冲幅值抖动影响较小，但腔长抖动会带来较大的脉冲时间抖动。因此要得到极低时间抖动和幅值抖动的锁模脉冲，必须对抽运激光功率和腔长的抖动加以控制。

A numerical model for nonlinear polarization rotation mode-locked fiber laser is established based on coupled wave equations and Jones matrix. The numerical results show that the power jitter of pump laser seriously affects amplitude jitter of mode-locked fiber laser. The root mean square (RMS) value of mode-locked pulse is 0.82%, and peak-to-valley value is 2.84% when random jitter of pump power is ±3%. Cavity length jitter has less effect on amplitude jitter. However, cavity length jitter leads to large timing jitter. So in order to get mode-locked pulses with very low timing jitter and amplitude jitter, pump laser power jitter and cavity length jitter must be controlled.