High-Power Broadband Thulium-Doped All-Fiber Superfluorescent Source at 2 $\mu{\rm m}$

We report on the experimental realization of a stable high-power all-fiber broadband amplified spontaneous emission (ASE) source at 1992 nm by using an MOPA configuration. The ASE source yields a maximum output power of 25 W with a slope efficiency of 49%, and the wavelength range spanned from 1930 to 2100 nm with a full-width at half-maximum bandwidth of 25 nm. In addition, we also measure the output power stability of the high-power broadband ASE source and a narrowband CW fiber laser with the same thulium-doped fiber main amplifier under incident pump power of 66 W. The output power fluctuation of the high-power broadband ASE source is below ±0.3%, which is much lower than that (±2.3%) of narrowband continuous wave thulium-doped fiber laser.