Single-frequency narrow-linewidth Tm-doped fiber laser using silicate glass fiber

Abstract

Single-frequency laser operation near $2\mu \mathrm{m}$ has been demonstrated in an all-fiber short-cavity $(2–6\mathrm{cm})$ distributed feedback laser cavity using both cladding- and core-pump configurations in a newly developed heavily Tm-doped multicomponent silicate glass fiber. Using a single-mode Er-doped fiber laser at $1575\mathrm{nm}$ as a core-pump source, a $2\text{-}\mathrm{cm}$-long distributed Bragg reflector fiber laser delivers single-frequency output at $1950\mathrm{nm}$ with laser linewidth less than $3\mathrm{kHz}$, which is, to the best of our knowledge, the narrowest linewidth demonstrated to date from any $2\mu \mathrm{m}$ single-frequency laser.