Single-mode laser output in a Yb^3+-doped fluorophosphate fiber

Abstract

A heterogeneous fiber with a Yb3+-doped fluorophosphate core and phosphate cladding was fabricated by the rod-in-tube and stacking technique. The concentration of Yb3+ in the core glass can be up to 6×1020 ions/cm3. The lasing threshold was 900 mW, and the lasing wavelength was centered at 1043 nm. A single-mode laser output with a slope efficiency of 13.6% with respect to the absorbed pump power was obtained, for the first time to our knowledge. The beam quality factor (M2) was measured to be 1.25. Thus, a fluorophosphate glass fiber is a good alternative for a gain medium in a short-linear-cavity single-frequency fiber laser.