Pei Wenxi, Li Hao, Huang Wei, Wang Meng, Wang Zefeng
Opt Express. 2021 Oct 11;29(21):33915-33925. doi: 10.1364/OE.440461.
We have reported a pulsed fiber gas Raman laser oscillator at 1.7 µm based on an all-fiber resonant cavity, which is made by splicing solid-core fibers with a 50-meter-long hydrogen-filled hollow-core photonic crystal fiber and further introducing homemade fiber Bragg gratings at the Raman wavelength. Pumping by a homemade pulsed 1540 nm fiber amplifier, a 1693 nm Stokes wave is obtained by pure rotational stimulated Raman scattering of H. The maximum optical-to-optical efficiency inside the hollow-core fiber is about 54% with the repetition frequency of 6 MHz, giving an average Raman power of 1.5 W, and the Raman threshold of peak power is as low as 3.6 W, which is more than 10 times lower than that of the single-pass structure. The relationship between pulse characteristics and Raman threshold is systematically studied, and the Raman threshold can be reduced dramatically when the repetition frequency of pulses is consistent with the resonant frequency of the cavity. This work provides good guidance for achieving low-threshold pulsed all-fiber gas Raman lasers, which is significant for development and application.
我们报道了一种基于全光纤谐振腔的1.7μm脉冲光纤气体拉曼激光器振荡器，该谐振腔由实心光纤与一根50米长的充氢空心光子晶体光纤熔接而成，并在拉曼波长处进一步引入自制的光纤布拉格光栅。通过自制的脉冲1540nm光纤放大器泵浦，利用氢气的纯转动受激拉曼散射获得了1693nm的斯托克斯波。空心光纤内的最大光光效率约为54%，重复频率为6MHz，平均拉曼功率为1.5W，拉曼峰值功率阈值低至3.6W，比单程结构低10倍以上。系统研究了脉冲特性与拉曼阈值之间的关系，当脉冲重复频率与腔的谐振频率一致时，拉曼阈值可大幅降低。这项工作为实现低阈值脉冲全光纤气体拉曼激光器提供了良好的指导，对其发展和应用具有重要意义。
