1090 nm all-fiberized and polarization-maintained fiber laser with narrow linewidth and near-single-mode beam quality

1090 nm all-fiberized and Polarization-maintained fiber laser with narrow linewidth and near-single-mode beam quality is demonstrated. We obtain a 668 W narrow linewidth linearly laser output with a linewidth of about 22GHz, the polarization extinction ratio is about 14dB, and the M2 is less than 1.1 at the maximum output power.