中文摘要：

采用再生锁模光纤激光器作为高质量微波源的振荡级，产生了高质量的微波信号。为了保证振荡环路的稳定性，采用了锁相技术和腔长控制；采用“单模光纤（SMF）＋法拉第旋光镜（FRM）”的结构代替了全保偏光纤，在腔内存在偏振扰动的情况下保证了系统稳定并降低了系统成本；在光生微波环路中加入了半导体光放大器（SOA），有效地提高了边模抑制比。最后，获得了的相位噪声为-98dBc／Hz（@10kHz）、线宽小于5Hz的20GHz微波信号。在10h的观测时间内，频率漂移小于2Hz，频率长期稳定性优于1×10-10。

英文摘要：

Optical pulse trains from mode-locked lasers carry low-jitter microwave signals. High-quality microwave signal could be obtained by using a band pass filter. A regeneratively-mode-locked fiber laser is used as an oscillation source to generate high-quality microwave signal. The phase-locked technology and cavity length control guarantee the stability of the system. The cost of the system is dramatically reduced by using the structure of ＂single-mode fiber＋Farady rotator mirror＂ instead of polarization-maintaining structure. A semiconductor optical amplifier （SOA） is introduced into the optical microwave loop, which improves the side-mode suppression ratio effectively. The generated 20 GHz microwave signal has great performance with phase noise of --98 dBc/Hz at 10 kHz and line-width less than 5 Hz. The frequency stability is better than 1×10-10 within 10 h observation.