Research Progress of Highly RE⁃Doped Silica Fibers and Short⁃Cavity Fiber Lasers (Invited)

Short-cavity single-frequency fiber lasers and high-repetition-rate passively mode-locked fiber lasers based on high gain rare-earth (RE) -doped fibers have significant applications in the manufacturing, healthcare, and military fields. Although RE doped silica fibers have advantages such as low propagation loss and easy splicing, the low fiber unit gain coefficient caused by the low doping concentration of RE ions severely limits the performance of short-cavity lasers. In recent years, with the expansion of fundamental research on RE-doped silica glasses and significant improvements in fiber fabrication techniques, RE-doped silica fibers have been developed and successfully applied for short-cavity lasers. The performance of short-cavity lasers at various wavelengths has been significantly improved, unleashing their potential for application. Considering fiber fabrication techniques and short-cavity laser applications using different RE-doped silica fibers, this review systematically analyzes the latest developments and application progress of highly RE-doped silica fibers and predicts their future development