基于光纤光栅法布里-珀罗腔的高效窄线宽光纤激光器

High Efficient Narrow Linewidth Fiber Laser Based on Fiber Grating Fabry-Perot Cavity

报道了采用双光纤光栅(FBG)法布里-珀罗(F-P)腔选模的线形腔结构窄线宽光纤激光器。激光器以高掺杂Er^(3+)光纤为增益介质,利用全光纤型法拉第旋转器(FR)抑制空间烧孔效应,通过两个短光纤光栅法布里-珀罗腔选模,产生了稳定的1534．83 nm单频激光输出。激光器采用两支976 nm单模激光二极管(LD)抽运,两端输出。激光器阈值抽运光功率为12 mW,在总抽运光功率为145 mW时总输出信号光功率为39．5 mW,单端最高输出信号光功率为22 mW。光-光转换效率为27％,斜率效率为29．7％。随着抽运功率的增加,激光器输出功率趋于饱和。采用延迟自外差方法精确测量光纤激光器线宽,实验中使用了15 km单模光纤延迟线,由于测量精度的限制,得到激光器的线宽小于7kHz。这种光纤激光器具有输出功率高、线宽窄、信噪比高的特点,可用于高精度的光纤传感系统。

A high Er^3＋-doped narrow linewidth fiber laser based on fiber Bragg grating （FBG） Fabry-Perot （F-P） cavity was demonstrated. Spatial hole burning effect was restrained by fiber Faraday rotator. Two short FBG F-P cavities were used as narrow bandwidth filters to discriminate and select laser longitudinal modes efficiently. Stable single frequency 1534.83 nm laser was acquired. Pumped by two 976 nm laser diodes （LDs） and two ends output, the fiber laser exhibited 12 mW threshold. Total 39.5 mW output power and one end 22 mW output power were obtained upon the maximum 145 mW pump power. Optical-optical efficiency was 27% and slope efficiency was 29.7%. The output power tended to be saturated when pump power increased. The 3 dB linewidth of laser was less than 7 kHz, measured by the delayed self-heterodyne method with 15 km single mode fiber. The high power narrow linewidth fiber laser can be used in high resolution fiber sensor system.