A dual-wavelength cladding-pumped Er-doped ZBLAN fiber laser emitting around 2.8 µm

We demonstrate an Er-doped ZBLAN fiber laser emitting around 2.8 μm, with a distinctive dual-wavelength cladding-pumped approach. The laser was jointly cladding-pumped by a 1.568 μm fiber laser and a 1.68 μm laser diode, potentially lifting pump power constraints and achieving an enhanced efficiency. The corresponding simulation shows that the setup has better thermal management than other conventional pumping methods. At the maximum output power of 1.3 W, the optical efficiency was 19.1% relative to all absorbed pump and 42.5% relative to absorbed 1.68 μm pump after injection. With a higher pump power and further cavity optimization, the laser is expected to produce competitive powers. Moreover, optimal pump wavelength, dual-wavelength pump power relationship, and basic pump choice were also investigated, providing critical insights for high-power, high-efficiency and low-thermal-load 2.8 μm fiber laser systems.