可调谐单频光纤激光器的研究进展（特邀）

可调谐单频光纤激光器具有调谐范围宽、光信噪比高、线宽窄、噪声低和兼容性好等特点，在光谱学、光学探测、光学传感、光纤通信等领域有着重要的应用价值，引起了国内外研究者的广泛关注。简单介绍了可调谐单频光纤激光的调谐和选模关键技术，对1.0、1.5、2.0 μm和中红外等不同波段的可调谐单频光纤激光器进行了总结与归纳，综述了其国内外研究现状，并展示了其在调谐范围、激光线宽、光信噪比、输出功率、输出功率平坦度等性能指标方面取得的成果。此外，结合笔者课题组近年来在可调谐单频光纤激光器方面的研究工作，介绍了基于复合腔结构实现可调谐单频光纤激光的最新进展，并展望了可调谐单频光纤激光器的未来发展趋势。

Research progress of tunable single-frequency fiber lasers (Invited)

Tunable single-frequency fiber lasers (TSFFLs) possess the characteristics of wide tuning range, high optical signal-to-noise ratio (OSNR), narrow linewidth, low noise, and excellent compatibility. They also have attracted extensive attention from researchers at home and abroad because of their important application value in the spectroscopy, optical detection, optical sensing, fiber communication and so on. In this paper, the tuning and longitudinal-mode selection key techniques of TSFFLs were introduced briefly. The TSFFLs with different wavelengths of 1.0 μm, 1.5 μm, 2.0 μm, and mid-infrared were summarized and their research status at home and abroad was reviewed. The results obtained in tuning range, laser linewidth, OSNR, power scaling, flatness of output power, and other output performances were also shown. In addition, combined with our new progress, the recent development of TSFFLs based on compound cavity structure was introduced. Furthermore, the future development trend of TSFFLs was also forecasted.