自调Q掺铒光纤激光器动态特性研究

Study on the dynamical behavior of self-Q-switched erbium-doped fiber laser

为了研究自调Q掺铒光纤激光器输出动态特性,采用搭建全光纤结构的线形腔和环形腔自调Q掺铒光纤激光器进行了理论分析和实验验证。实验中,当抽运功率达到起振阈值后,随着抽运功率的增加,用示波器观察输出激光,线形腔输出激光依次经历了连续波、自调Q两种运行状态,由于抽运功率的限制,未能再次出现连续波运行状态,而环形腔输出激光则先经历了自调Q运行状态,然后是连续波运行状态;线形腔在抽运功率21m W^190m W的范围内,可获得脉冲宽度8μs^100μs范围内可调、重复频率2.5k Hz^54k Hz范围内可调的自调Q脉冲;环形腔在抽运功率为16.2m W^110m W时,可获得的脉冲宽度在165μs左右。结果表明,自调Q掺铒光纤激光器因腔结构的不同,输出激光动态特性也不同;线形腔和环形腔均有自调Q脉冲输出,但线形腔自调Q范围更大。

In order to study the dynamical behaviors of self-Q-switched erbium-doped fiber lasers,all-fiber self-Q-switched erbium-doped fiber lasers with linear cavity configuration and ring cavity configuration were constructed. Theoretical analysis and experimental verification were also carried out. In the experiment,when pump power reached the threshold,output laser was observed by oscilloscope with the increase of pump power. Linear cavity laser output experienced two operation states of continuous wave（ CW） and self-Q-switched in turn and failed to appear CW operation state again because of the constraint of pump power. Ring cavity laser output experienced self-Q-switched operation state at first and then CW operation state. For linear cavity,self-Q-switched pulses can be obtained with pulse width from 8μs to 100μs and repetition rate from 2. 5k Hz to 54 k Hz in pump power range from 21 m W to 190 m W. For ring cavity,self-Q-switched pulses can be obtained with pulse width about 165μs and repetition rate about 3k Hz at pump power range from 16. 2m W to 110 m W. The results show that dynamical behaviors of output laser are different because cavity configurations of self-Q-switched erbium-doped fiber laser are different. Although both linear and ring cavities have self-Q-switched pulse output,the range of self-Q-switched pulse is wider for linear cavity.