基于干涉环结构的调Q光纤激光器

从光纤干涉环中受激瑞利散射(SRS)和光纤中受激布里渊散射(SBS)共同作用调Q的原理出发,研究了光纤干涉环耦合比及环长对调Q光纤激光器输出激光特性的影响。分别采用耦合比为50∶50,80∶20,90∶10的光纤干涉环在不同环长下搭建掺Er3 调Q光纤激光器进行实验。实验结果表明,干涉环的耦合比和环长是影响输出激光特性的关键因素,耦合率(~10%)的干涉环适宜产生脉冲激光,具有高耦合比干涉环的光纤激光器只有连续激光输出;环长根据干涉环耦合率(~10%)在2 m附近调整可以获得理想脉冲激光输出,环长过短时产生输出激光的弛豫振荡,反之产生输出激光脉冲的分裂。采用耦合比为90∶10,环长为2 m的光纤干涉环时,在37 mW的抽运功率下获得脉宽7.2 ns,重复频率212.4 kHz,输出功率5.4 mW的脉冲激光,脉冲波形较好,峰值功率有~30%的波动。

Q-Switched Fiber Laser with a Ring Interferometer

The co-operation of stimulated Rayleigh scattering (SRS) in fiber interference loop and stimulated Brillouin scattering (SBS) in fiber can change Q value in resonant cavity, based on which an all-fiber Er-doped Q-switched fiber laser with interference loop is designed. In the experiments, the attributes of output laser exploiting interference loops with different coupling ratios and lengths were investigated. A train of pulse laser with pulse duration of 7.2 ns, repetitive frequency of 212.4 kHz, average output power of 5.4 mW at pump power of 37 mW was obtained which had a good waveform and a peak power fluctuation of ～30%. The results show that the interference loop with very high coupling ratio has no contribution to the generation of pulse laser and the coupling ratio of ～10% is suitable for it. Even if the coupling ratio of ～10% is chosen, the length of the loop has influence on the attribute of the output laser pulse and good output can be obtained at the length around 2 m.