Compact, 4-W, 2.3-μm continuous-wave all-fiber Raman laser based on fluorotellurite glass fiber

We demonstrate a compact, continuous-wave, all-fiber Raman laser operating at 2.3 μm, based on a home-made fluorotellurite fiber with integrated fiber Bragg gratings. Pumped by a 1980-nm continuous-wave thulium-doped fiber laser, the Raman fiber laser delivers 2.3 μm emission with a maximum power of 3.9 W and a slope efficiency of 20% with respect to the launched pump power. Additionally, it exhibits a low pump power threshold of 8.3 W. This represents the first, the best of our knowledge, continuous-wave Raman fiber laser at 2.3 μm and the first Raman laser oscillator based on fluorotellurite fiber. This work highlights the potential of fluorotellurite fibers for mid-infrared Raman fiber lasers, while the compact laser scheme paves the way for high-power fiber lasers in the 2.3 μm region.