Spectral Manipulations of Random Fiber Lasers: Principles, Characteristics, and Applications

Random fiber lasers (RFLs), a new variety of random lasers, have become a vigorous research spot over the past decades. RFLs possess superiorities in efficiency, structural flexibility, directionality, cost, etc. Particularly, RFLs are discovered to be good platforms for the construction of various forms of high-performance lasers. Herein, recent progress in the spectral manipulation of RFLs and the applications of spectral-tailored RFLs are reviewed. Both theoretical and experimental investigations of the unique spectral properties of RFLs up to now are presented. The superior wavelength flexibility of RFLs which can achieve any desired lasing wavelength in the 1–2.1 µm band is highlighted. Via spectral manipulation, RFLs have shown the capability of high-spectral-purity, narrow-bandwidth, and multi-wavelength output. Furthermore, the RFLs featuring unique spectral properties can lead to various promising applications, which are concisely summarized, including optical fiber communication, optical fiber sensing, imaging, supercontinuum generation, nonlinear-frequency conversion, mid-infrared lasing pump sources, and laser-driven inertial confinement fusion motivation. The challenges and prospects for RFLs are also discussed.