全光纤调Q激光器腔内脉宽压缩技术

Internal Pulse Width Compression Technology of All-fiber Q-switched Laser

为了压缩MOPA全光纤调Q激光器脉冲宽度,对谐振腔基本参数进行了研究。首先,根据速率方程理论推导出脉冲宽度的表达式,通过数值解建立表达式参数与脉冲宽度的关系。然后,分析增益光纤长度、腔镜输出透过率、Q开关性能等谐振腔基本参数对全光纤调Q种子源输出脉冲宽度的影响并通过实验来逐一验证结果。最后,通过优化的参数搭建全光纤调Q激光器,在重复频率为20 k Hz时,得到脉冲宽度为54 ns、平均功率为0.86 W的种子激光输出。在重复频率为100 k Hz时,对脉宽142 ns、平均功率为1.66 W的种子光进行预放大和功率主放大,最终得到平均功率120 W、脉宽180 ns、光谱宽度为0.67 nm的稳定脉冲激光输出。通过提升AOM性能、减小增益光纤长度等参数优化方式构建调Q光纤激光器,能有效压缩谐振腔内脉冲宽度。

In order to compress the pulse width of MOPA all-fiber Q-switched lasers,the basic parameters of the resonator were studied. Firstly,the expression of the pulse width was deduced according to the rate equation theory,and the relationship between the expression parameters and the pulse width was established by numerical solution. Then,the effects of gain fiber length,cavity output transmittance and Q-switch performance on the output pulse width of all-fiber Q-switched source were analyzed and the results were verified experimentally. Finally,an all-fiber Q-switched laser was constructed by optimizing the parameters. At the repetition frequency of 20 k Hz,the seed laser output with pulse width of 54 ns and average power of 0. 86 W was obtained. At the repetition frequency of 100 k Hz,the seed light with the pulse width of 142 ns and the average power of 1. 66 W was used to prevent large and main power amplification,and finally the stable pulse laser output with average power of 120 W,pulse width of 180 ns and spectral width of 0. 67 nm was obtained.The Q-switched fiber lasers can be constructed by optimizing the AOM performance and reducing the length of the gain fiber to optimize the pulse width of the resonator.