中文摘要：

提出一种腔内损耗小的基于半导体光放大器（SOA）交叉增益调制效应（XGM）的主动锁模光纤激光器结构。使用光环行器成功减小了激光器的腔内损耗，提高了激光器的输出功率。从理论上对有理数谐波锁模过程中腔内脉冲复合的物理机制进行了详细分析。利用有理数谐波锁模技术，在调制频率为10GHz下，得到了重复频率为30GHz的皮秒级光脉冲序列输出，其峰值功率约0．5mW。由于半导体光放大器的宽增益谱与滤波器的较大可调谐范围，使得激光器输出可以在较大的波长可调谐范围内保持较大功率输出。成功实现了调制频率为20GHz的谐波锁模短光脉冲输出，可调谐范围达40nm，峰值功率大于0．65mW。半导体光放大器和激光器的短腔长保证了激光器的长期稳定性。

英文摘要：

An actively mode-locked fiher ring laser based on cross-gain modulation （XGM） effect of semiconductor optical amplifier （SOA）, with a small intracavity loss, is proposed and demonstrated. By using an optical circulator, the intracavity loss was reduced and the output power of the laser was increased. The physical mechanism of pulse multiplication in ring cavity during rational harmonic mode locking process has also been theoretically analyzed in detail. Taking advantage of rational harmonic mode locking technology, an optical pulse train with a repetition frequency of 30 GHz was obtained using a modulation frequency of 10 GHz, and the peak power was about 0.5 mW. With broad gain spectral width of SOA and large tuning range of filter, the output power of the output pulse train could keep big enough over a large tuning range. Harmonic mode locking at 20 GHz was successfully achieved and the peak power of the output pulse train was more than 0.65 mW over a 40 nm tuning range. The semiconductor optical amplifier and the short length of the ring cavity ensure the long term stability of the laser.