Tunable kHz distributed feedback fiber laser enabled by glass additive-manufacturing

techniques can be considered as an attractive alternative to the often-cumbersome traditional manufacturing routes. With the use of high-power lasers, localized hot zones that are necessary for glass making can be obtained rapidly. For instance, Laser-Powder-Deposition enables rapid fabrication of short, high gain fibers used in e.g., distributed feedback fiber lasers (DFFL). DFFLs offer sought after performance suitable for a broad range of applications in modern photonics i.e., superior stability and narrower, single-frequency linewidth compared to conventional fiber lasers. Tunable, narrow laser sources with output in eye-safe spectrum are desired for sensing, signal multiplexing, LIDAR systems, quantum applications etc. In this work we present DFFL obtained using Laser-Powder-Deposition made Er-doped silica fiber. Milliwatt level, narrow line lasing (< 704 kHz, equipment limited) was obtained using a phaseshifted grating written in 16 mm long fiber. The backward slope efficiency was as high as 24% when pumping at 976 nm. The results presented in this work showcase new possibilities in fiber fabrication that were unlocked through laser-assisted additive manufacturing. This fiber laser sets the stage for the future of rapid fabrication of advanced fiber devices through unconventional manufacturing routes.