Continuous-Wave 1.7 μm All-Fiber Gas Raman Laser Source

We report the first continuous-wave (CW) all-fiber gas Raman laser source. An all-fiber gas cavity with a length of 50 m and filled with high-pressure hydrogen was formed by fusion-splicing solid-core single-mode fiber and photonic band gap hollow-core fiber. A high-power CW 1540 nm fiber amplifier was used as the pump source, and efficient CW 1693 nm Stokes laser was obtained by pure rotational stimulated Raman scattering of hydrogen. Furthermore, by adding a high-reflection fiber Bragg grating with a center wavelength of 1540 nm at the output end of the all-fiber gas cell, the Raman threshold is reduced by 38.2%, the maximum output Stokes power is 2.15 W, and the Raman conversion efficiency inside the gas cell is 72.2%, while the optical-to-optical conversion efficiency in terms of the total pump power is 31.7% due to the relatively high splicing loss. This work provides a feasible way for compact, high-efficiency, and high-power 1.7 μm fiber laser. © 2021, Chinese Lasers Press. All right reserved.