使用20 W/1.06 μm掺镱双包层光纤激光器作为抽运源, 抽运由300 m国产掺磷光纤和光纤光栅构成的级联拉曼谐振腔, 进行了高功率1.48 μm级联拉曼光纤激光器的实验研究。实验研究了不同反射率的输出光纤光栅对拉曼激光阈值和激光效率的影响。结果表明激光阈值随输出光纤光栅反射率的增加而减小。当使用25.7%的输出光纤光栅时, 激光器具有最大的转换效率, 在入腔抽运功率为12.1 W时, 获得了最大2.8 W/1.48 μm连续波激光输出, 相应的激光斜率效率和转换效率分别为31.3%和23.1%。通过监测1.48 μm激光的最大输出功率, 2 h内的功率波动小于5%。

A high power home-made phosphosilicate fiber cascaded Raman laser pumped by 20 W/1.06μm Yb-doped double-clad fiber laser is reported. The effect of reflectivity of output couplers on the laser threshold and efficiency are investigated experimentally. The laser threshold decreases with increasing the reflectivity of output FBG. The maximum continuous-wave output power of 2.8 W is obtained by 25.7% output coupler while the launched pump power is 12.1 W. The corresponding slope efficiency and the conversion efficiency are about 31.3% and 23.1%, respectively. At the maximum output power, the power fluctuation at 1.48 μm in two hour is observed to be less than 5%.