中文摘要：

为满足全光采样系统对低时域抖动、窄脉冲宽度和高重复频率飞秒光纤激光器的需求，结合数值仿真，在实验的基础上利用非线性偏振旋转锁模原理，初步实现了自由运转被动锁模掺铒飞秒光纤激光器，激光器锁模输出脉冲的基本重复频率为6．028MHz，平均输出功率为1．07mw，中心波长为1570．3nm，光谱宽度为33．2nm，理论推算出傅里叶变换受限脉冲的时域宽度为78fs；通过增大输出耦合器的分束比，可以提高锁模输出脉冲的平均功率；同时，测量了锁模脉冲基本重复频率的稳定性。该激光器的操作和调节简单，在锁模情况下能够长时间稳定运行，其全光纤结构更有利于小型化和便携化。

英文摘要：

All-optical sampling system needs femto-second fiber laser with low time jitter, narrow pulse width and high repetition rate as sampling pulse source. Based on the numerical simulation, passively mode-locked erbium-doped femto-second fiber laser was demonstrated via nonlinear polarization rotation （NPR） effect. The fundamental repetition rate of the fiber laser was 6.028 MHz, the average output optical power was 1.07 mW, the central wavelength was 1 570.3 nm, and the spectral width was 33.2 nm, the corresponding Fourier transform limited pulse width of 78 fs was calculated. The average output optical power could be improved by increasing the coupling-ratio of the output optical coupler in the allfiber cavity. The stability of the fundamental repetition rate of the laser was also measured. The femtosecond laser is simple and easy to operate. Furthermore, the laser is compact and portable for the all fiber cavity structure.