All-fiber ultra-narrow linewidth 50 pm Tm3+-doped double-clad fiber laser at 1948 nm

摘要

A high stability all-fiber LD-clad-pumped Tm~(3+)-doped fiber laser was reported. The fiber laser had the ultra-narrow linewidth 50 pm at 1.948 μm with the maximal output power of 12.8 W. The slope efficiency was 28.9%, and threshold was 5.7 W. The double-clad Tm~(3+)-doped fiber core was multi-mode, which had a demission of 25/250 μm with the core NA of 0.1 and inner-clad NA of 0.46. The high reflectivity coupler FBG was directly written into the single-mode passive photosensitive optical fiber core, which had a core diameter of 15 μm and NA of 0.1. The cavity was build-up by the high reflectivity FBG and the output fiber end Fresnel reflectivity.