Efficient lasing at near 3 μm by a Dy-doped ZBLAN fiber laser pumped at ∼ 1.1 μm by an Yb fiber laser

Operation of a single-clad Dy³⁺-doped ZrF₄-BaF₂-LaF₃-AlF₃-NaF (ZBLAN) fiber laser operating at mid-infrared near 3 μm is presented. The laser is pumped by an Yb³⁺-doped silica fiber laser centered at 1088 nm. An output of near 0.1 W with a slope efficiency of up to 23% with respect to absorbed pump power was measured. The laser performance, theoretical modeling and laser spectrum of Dy fiber laser system with respect to various cavity losses are studied. The experimental slope efficiency is more than 4.5 times higher than the previous demonstration, and is 64% of the Stokes efficiency limit. The efficiency was improved by using cavity mirrors of reflectivities of 99 and 50%. The emission central wavelength and spectral width are found to be dependent on the pump power and output coupler, reflectivity.