High-efficiency, single-frequency, polarized thulium-doped silica fiber lasers

We report on single-frequency, linearly polarized, high-concentration thulium-doped silica fiber-distributed Bragg reflector lasers operating at wavelengths between 1908 and 2050 nm with high efficiencies up to 48% and high powers up to 1 W. Low relative power noise and frequency noise are demonstrated using a low-noise pump diode.