High-Power Thulium-Doped All-Fiber Superfluorescent Source With Ultranarrow Linewidth

The narrow-band superfluorescent source is a promising optical source in various fields. We constructed a novel scheme for the narrow-band all-fiber thulium-doped superfluorescent source and demonstrated the power scaling based on multistage amplifiers. A stable narrow-band thulium-doped all-fiber superfluorescent seed source, a three-stage preamplifier, and a main amplifier were adopted. The maximum output power reached 228 W with the slope efficiency of 50%. The full-width at half-maximum (FWHM) was 0.19 nm, and the center wavelength was 1968.1 nm. To the best of our knowledge, this is the highest power of the narrow-band thulium-doped all-fiber superfluorescent source at 2 m, which is only limited by available pump power for the time being.