超宽调谐随机拉曼光纤激光器的研究

Random distributed feedback Raman fiber lasers have attracted much attention in recent years due to their wide applications in fields such as research, biology, communication and environmental monitoring. However, the output wavelength range of the random fiber is still limited, which prevents the full exploration of its advantages. Unlike the conventional laser, random Raman fiber laser employs the distributed Rayleigh scattering as feedback and Raman scattering as the laser gain. As is known, the Rayleigh scattering exists at the whole wavelength range and the Raman scattering is wavelength flexible because it does not rely on the electron energy level of the gain medium. As a result, the random Raman fiber laser is born to output ultra-broadband tunable laser. In this project, we will investigate the characteristics of the novel ultra-broadband tunable random Raman laser. Through the numerical simulation and experimental research, we aim to achieve tunable wavelength laser between 1.1 to 2.0 μm by combination of the tunable ytterbium-doped fiber laser pumped wavelength-insensitive random Raman laser and the cascaded Raman process.

基于随机分布反馈的拉曼激光器在科研、生物、通信、环境监测等领域均有重要应用，是近几年来光纤激光技术领域的研究热点。但是，目前随机拉曼光纤激光器的输出波长范围依旧有限，尚未完全发挥出其固有优势。与常规光纤激光器不同，随机拉曼光纤激光器利用光纤中固有的瑞利散射作为反馈，拉曼散射提供激光增益。瑞利散射在整个波段都是存在的，同时，拉曼散射不依赖于介质的电子能级而具有波长灵活的特点，因此随机拉曼光纤激光器天生具有超宽谱调谐输出的特性。本项目拟开展新型超宽调谐随机拉曼光纤激光器的研究，利用宽调谐的掺镱光纤激光器泵浦波长不敏感的随机拉曼光纤激光器，同时结合级联拉曼过程，通过理论模拟和实验研究，实现1.1～2微米范围内任意波长可调谐的随机激光输出。

基于分布反馈的随机拉曼激光器在科研、生物、通信、环境监测等领域均有重要应用，是近几年来光纤激光技术领域的研究热点。本项目利用随机拉曼光纤激光器天生具有超宽谱范围连续调谐输出的特性，开展了新型超宽调谐随机拉曼光纤激光器的研究。利用宽调谐的掺镱光纤激光器泵浦波长不敏感的随机拉曼光纤激光器，同时结合级联拉曼过程，实现了项目的研究目标，主要包括：采用两级放大器，通过理论模拟和实验研究，有效的抑制了长波处的自发辐射，最大获得了输出功率100W，波长1020-1080nm连续可调谐泵浦激光器；采用高非线性光纤作为拉曼增益光纤，通过半开放的随机拉曼激光器，实现了高达9阶的随机拉曼激光输出，其波长调谐范围覆盖1.02-1.94μm，最大的输出功率为6.1W，对应光光转换效率为25%；围绕1480nm激光对于高功率单频1560nm 掺Er激光的同代泵浦、1800nm随机激光对于高功率2000nm 掺Tm激光的同代泵浦展宽研究。通过随机拉曼激光器实现了100W的1480nm激光输出，实现了大于100W的1800nm激光输出，这些工作均为随机拉曼激光器在该波长的世界记录。