>1 kW all-fiberized narrow-linewidth polarization-maintained fiber amplifiers with wavelength spanning from 1065 to 1090 nm.

We demonstrate all-fiberized, kilowatt-level, narrow-linewidth, Yb-doped and polarization-maintained (PM) amplifiers with a central wavelength spanning from 1065 to 1090 nm. The laser system consists of a tunable single-frequency laser seed and multistage PM fiber amplifiers in the master oscillator power amplifier configuration. The stimulated Brillouin scattering effect is suppressed by phase modulation based on a white noise source. The linewidth (Δλ∼0.12  nm at 1 kW), polarization extinction ratio (PER>13  dB) and beam quality (M∼1.2) are well maintained during the power scaling process, and the slope efficiency of this system is 70.8%.