提出了一种再生锁模光纤激光器的双腔稳定控制方案,利用锁相环检测光谐振腔腔长变化引起的微波频率漂移,并用压电陶瓷光纤拉伸器进行反馈补偿。利用光电再生腔中的混频器比较两个同频微波信号的相位,得到光电再生腔的腔长变化,并用电移相器反馈补偿光电再生腔的腔长变化。本研究中再生锁模激光器输出了重复频率为10 GHz、脉冲宽度为16.6 ps的光脉冲。光电再生腔输出了重复频率为10 GHz的微波信号,其边模抑制比为40 dB,相位噪声为-127 dBc/Hz,70 min内的频率漂移小于1 Hz。与现有的再生锁模方案相比,本方案实现了光谐振腔腔长和光电再生腔腔长的同时控制,输出的微波信号频率稳定度高,光脉冲质量好,可实现激光器的长时间稳定工作。

A dual-cavity stable control scheme for regenerative mode-locking fiber laser is proposed. The scheme uses phase-locked loop to detect the microwave frequency drift caused by cavity length change of resonant cavity and realizes feedback compensation with piezoelectric ceramic. We use a microwave mixer to compare the phases of two microwave signals with the same frequency in photoelectric regenerative chamber. Cavity change is obtained and compensated by phase shifter. In this study, the regenerative mode-locking fiber laser outputs optical pulses with repetition frequency of 10 GHz and pulse width of 16.6 ps. The optoelectronic regenerative cavity outputs microwave signal with repetition frequency of 10 GHz,side-mode suppression ratio of 40 dB, phase noise of -127 dBc/Hz and the frequency shift smaller than 1 Hz in 70 min. Compared with the present regenerative mode-locking scheme, the proposed scheme can control cavity lengths of optical resonator and optoelectronic regenerative cavity simultaneously, and can output microwave signal with stable frequency and high quality pulse. The regenerative mode-locking fiber laser can work stably for a long time.