Quasi-all-fiber structure CW mid-infrared laser emission from gas-filled hollow-core silica fibers

Abstract

A quasi-all-fiber structure CW mid-infrared fiber lasers based on gas-filled hollow-core fibers (HCFs) is firstly reported here. Through a thermally tapered single-mode fiber, the CW tunable 1.5 μm fiber pump light is coupled into an acetylene-filled anti-resonance HCFs, and the coupling point is sealed with epoxy glue to ensure the stability and gas tightness, then the HCFs is filled with acetylene gas by a specially designed small gas cell, just like an end cap. When the pump is precisely tuned to the resonance with the absorption lines of acetylene, CW mid-infrared emission around 3.1–3.2 μm is generated at room temperature with maximum power of ~180 mW and slope efficiency of ~14%. The laser threshold is also discussed as function of acetylene pressure. This work opens new opportunities for all-fiber mid-infrared lasers of new wavelengths those unavailable for traditional rare-earth-doped fibers.