Narrow linewidth 80 W tunable thulium-doped fiber laser

We describe the design and characterization of a tunable narrow linewidth thulium-doped fiber laser source which combines a core-pumped preamplifier and high power cladding-pumped amplifier, providing >80 W average power. The single-frequency wavelength output from 1.92 um to 2.01 µm is digitally tunable to target specific atmospheric absorption and transmission windows for applications targeting atmospheric transmission at 2 µm. Results from preliminary thermal blooming studies are presented.