窄线宽单频单偏振环行腔掺铒光纤激光器

Narrow-linewidth single-frequency single-polarization Er-doped fiber ring laser

为了获得稳定的窄线宽单频单偏振掺铒光纤激光器输出，对采用饱和吸收体的环行腔结构掺铒光纤激光器进行了研究．实验中采用未抽运掺铒光纤作为饱和吸收体形成窄带滤波器，并选用高反射率的光纤光栅作为波长选择元件，同时采用具有高消光比的保偏环行器来获得单偏振激光．窄线宽单频单偏振环行腔掺铒光纤激光器的峰值波长可以通过拉伸光纤光栅进行调谐，调谐的范围为1548～1552nm．当抽运功率为275mw时获得的输出最大功率55．4mw．通过采用光纤延迟自外差法的线宽测试技术测量出该环行腔掺铒光纤激光器的20dB线宽为3kHz，光纤激光器的输出光偏振态长时间稳定在偏振度99．9％．这种窄线宽单频单偏振掺铒光纤激光器可以作为相干激光雷达的稳定信号源．

In order to acquire a stable narrow-linewidth single-frequency polarized Er-doped fiber laser, the ring fiber laser with a saturable absorber was studied. In the experiments, an un-pumped Er-doped fiber was used as saturable absorber to form an optical narrow-bandwidth filter, a fiber bragg grating with high reflectivity was adopted as coarse wavelength selective component, and a polarization-maintaining optical circulator with high extinction ratio was applied to acquire single polarization laser. The peak wavelength of the Erdoped ring fiber laser can be tuned from 1548 nm to 1 552 nm by pulling the fiber bragg grating. The maximum output power was 55.4row when the pump power arrived at 275mW. The 20dB linewidth of the Er-doped ring fiber laser was measured to be 3kHz with the fiber delayed heterodyne method. It was found that the polarization of the Er-doped ring fiber laser was very stable for a long term, and the degree of polarization was 99.9%. This narrow-linewidth single-frequency single-polarization Er-doped fiber laser can be used as stable signal source for coherent laser radar.