为了实现高重复频率和高功率的光脉冲，实验采用Er3+/Yb3+共掺双包层光纤作为增益介质，稳定的中心波长为976 nm的高功率半导体激光器作为泵浦源，利用非线性偏振旋转锁模技术，得到稳定的自起振锁模光脉冲。当泵浦功率为2.4 W时，激光器输出重复频率为8.829 MHz的连续锁模光脉冲，平均输出功率为52.5 mW，自起振锁模泵浦阈值功率为0.6 W，并观测到了稳定的高阶谐波锁模、调Q和调Q-锁模光脉冲输出。

The passive harmonically mode-locked fiber ring laser with a small segment of Er3+/Yb3+ codoped double-clad fiber as gain medium, which is pumped by 976 nm LD laser and mode-locked exploiting the nonlinear polarization rotation technique, was successfully demonstrated for the generation of self-starting mode-locked pulses. When the laser was pumped at 2.4 W, stable mode-locked pulses were obtained at the repetition rate of 8.829 MHz through modulating the fiber polarization controllers. The average output power of the fiber laser was 52.5 mW, and the threshold power of the self-starting mode-locked pumping is 0.6 W. The high-order mode-locked, Q-switched and Q-switched-mode-locked pulses were also observed experimentally.