Double-clad Tm3+-doped silica fiber laser with Bragg grating inscribed directly into active core by femtosecond laser

Abstract

We report for the first time to inscribe the Fiber Bragg Grating (FBG) in Tm3+-doped multimode double-clad silica fiber by 800 nm femtosecond laser with a phase mask. The 1.35 μm period Bragg grating is written into the fiber core, which is responded to the laser center wavelength located at nearly 1960 nm. Continuous wave total output power of 11.5 W is obtained under the launched pump power of 29.8 W, corresponding to a slope efficiency of 45.0% and a conversion efficiency of 38.6%.