210 W single-frequency, single-polarization, thulium-doped all-fiber MOPA

A high-power single-frequency, single-polarization, thulium-doped all-fiber master-oscillator power-amplifier (MOPA) is demonstrated by using all-polarization-maintaining (all-PM) thulium-doped fiber and all-PM-fiber components. The MOPA yielded 210 W of single-frequency, linear-polarized laser output at central wavelength of 2000.9 nm with a polarization extinction ratio (PER) of >17 dB. No indication of stimulated Brillouin scattering (SBS) could be observed at the highest output power level, and the output power was only currently limited by available pump power. To the best of our knowledge, this is the first demonstration of average output power exceeding 200 W from a single-frequency, single-polarization, thulium-doped all-fiber laser at 2 µm wavelength region.