3 W tunable 1.65 µm fiber gas Raman laser in D2-filled hollow-core photonic crystal fibers

Abstract We demonstrate here a multi-watt tunable 1.65 µm fiber laser based on deuterium-filled hollow-core photonic crystal fibers (HC-PCFs) by stimulated Raman scattering (SRS). Owing to the fiber transmission properties of the HC-PCFs, pure rotational Stokes wave at 1.65 µm can be generated when pumped with a tunable 1.5 µm erbium-doped fiber amplifier (EDFA). When pumped at 1540 nm, with a 20-meter-long HC-PCF filled with 16 bar deuterium, a record average Stokes power of ∼2.91 W at 1645 nm is achieved, which is about 3.64 times higher than the similar experiment previously reported, and the corresponding power conversion efficiency is about 58%. Over the whole Stokes tunable range of 1645 to 1656 nm, the average output power is >2.5 W and the conversion efficiencies are >54%. A numerical model is also established to analyze the rotational SRS process in deuterium-filled HC-PCFs, the simulation results are in good agreement with experiments. This work opens a new opportunity for high-power tunable fiber lasers operating in the 1.7 μm band.