Yang Lingling, Wu Duanduan, Wang Yingying, Dai Shixun
Opt Express. 2025 Mar 24;33(6):14304-14313. doi: 10.1364/OE.557466.
We demonstrate a low-threshold, broadband-tunable cascaded Raman fiber pulsed laser utilizing highly GeO-doped silica and AsS fibers as Raman gain media. As a result of the high Raman spectral purity of the first-order Raman laser and the high Fresnel reflection coefficient of the AsS fiber resonant cavity, a second-order nanosecond pulsed Raman laser with a center wavelength of 2335 nm is achieved, with a peak threshold power of 95 W with a 1970nm nanosecond pump source and corresponding to 8.4 W with a 2150 nm first-order Raman laser as the pump source. The maximum single-pulse energy and spectral purity of the second-order Raman laser are measured at 5.1 μJ and 47.2%, respectively. Furthermore, through precise tuning of the central wavelength in the gain-modulated pulsed source, the second-order Raman laser achieved a wavelength tuning range spanning 74 nm, from 2303 nm to 2377 nm. To the best of our knowledge, this achievement establishes the broadest wavelength tuning range reported to date for cascaded Raman fiber lasers operating in the 2.3 μm spectral region.
我们展示了一种低阈值、宽带可调谐的级联拉曼光纤脉冲激光器，它利用高掺GeO二氧化硅光纤和AsS光纤作为拉曼增益介质。由于一阶拉曼激光器具有高拉曼光谱纯度以及AsS光纤谐振腔具有高菲涅尔反射系数，实现了中心波长为2335nm的二阶纳秒脉冲拉曼激光器，使用1970nm纳秒泵浦源时峰值阈值功率为95W，以2150nm一阶拉曼激光器作为泵浦源时对应的阈值功率为8.4W。二阶拉曼激光器的最大单脉冲能量和光谱纯度分别测得为5.1μJ和47.2%。此外，通过在增益调制脉冲源中精确调谐中心波长，二阶拉曼激光器实现了74nm的波长调谐范围，从2303nm至[原文此处有误，应为2377nm]2377nm。据我们所知，这一成果确立了迄今为止报道的在2.3μm光谱区域工作的级联拉曼光纤激光器的最宽波长调谐范围。
