High-efficiency fluoroindate glass fiber laser

We report the high-efficiency operation of a 3.05 µm dysprosium-doped fluoroindate glass fiber laser that is in-band pumped at 2.83 µm using an erbium-doped fluorozirconate glass fiber laser. The demonstrated slope efficiency of the free-running laser of 82% represents approximately 90% of the Stokes efficiency limit; a maximum output power of 0.36 W, the highest for a fluoroindate glass fiber laser, was recorded. Narrow-linewidth wavelength stabilization at 3.2 µm was achieved by utilizing a first-reported, to the best of our knowledge, high-reflectivity fiber Bragg grating inscribed in the Dy³⁺-doped fluoroindate glass. These results lay the foundation for future power-scaling of mid-infrared fiber lasers using fluoroindate glass.