光纤光栅主动稳频的短直线腔单频光纤激光器

Short Linear Cavity Single-Frequency Fiber Laser with Active Frequency Stabilization by Fiber Bragg Grating

利用1.8cm长的Er3+/Yb3+共掺磷酸盐玻璃光纤作为增益介质制作了一个可调谐的短直线腔窄线宽单偏振单纵模光纤激光器。其谐振腔反射镜由高反射率的光纤布拉格光栅(FBG)和低反射率的保偏光纤FBG构成,使用976nm单模半导体激光器作为抽运源。当进入谐振腔的抽运功率为360mW时获得了输出功率65mW,信噪比大于70dB,线宽约为3kHz,偏振消光比达到40dB的激光输出。另外,通过使用压电陶瓷(PZT)调节增益光纤的长度实现了激光波长的电调谐,其调谐斜率约为14.2 MHz/V。采用边频锁定的方式进行主动稳频,使得激光输出的长期频率波动从25MHz/10s减少到了2.5MHz/h,从而实现了全光纤结构的高功率、高频率稳定性的单频光纤激光器。

A short-linear-cavity all-fiber laser configured with 1.8 cm Er3＋/Yb3＋ co-doped phosphate glass fiber is demonstrated experimentally with single frequency and high frequency stabilization.The fiber laser is composed of a high-reflectivity fiber Bragg grating（FBG） and a polarization-maintaining FBG.The pump is from a semiconducter laser of single mode at 976 nm.When the pump power into the cavity is 360 mW,the output power of the laser reaches more than 65 mW;the signal-to-noise ratio is higher than 70 dB;the laser linewidth is about 3 kHz and the polarization extinction ratio is about 40 dB.Moreover,the length of the active fiber is tuned by a piezoelectric transducer（PZT）,and the laser frequency tunable slope is 14.2 MHz/V.Then the laser frequency is stabilized on FBG by using side frequency locking method.The long term frequency fluctuation is reduced from 25 MHz/10 s to 2.5 MHz/h.