We have demonstrated dual-wavelength continuous-wave oscillation at 3 and 2 μm with a Ho-doped ZrF<sub>4</sub>– BaF<sub>2</sub>– LaF<sub>3</sub>– AlF<sub>3</sub>– NaF fluoride-glass fiber laser by use of a cascade oscillation scheme. We have shown that the fiber laser operates with a high slope efficiency of 52% (at 3 and 2µm) with respect to the absorbed pump power. With a 6.5-m-long fiber we achieved an output power of 90 mW at each of the wavelengths that was limited only by the pump power, and the 3-µm output power is to our knowledge higher than any previously reported level with 3-μm Ho<sup>3+</sup> -doped fiber lasers.
© 1998 Optical Society of America
(140.3070) Lasers and laser optics : Infrared and far-infrared lasers
(140.3510) Lasers and laser optics : Lasers, fiber
(140.5680) Lasers and laser optics : Rare earth and transition metal solid-state lasers
Tetsumi Sumiyoshi and Hitoshi Sekita, "Dual-wavelength continuous-wave cascade oscillation at 3 and 2 μm with a holmium-doped fluoride-glass fiber laser," Opt. Lett. 23, 1837-1839 (1998)