250W continuous-tunable all-fiberized single-frequency polarization-maintained amplifiers with wavelength spanning from 1065 nm to 1090 nm

In this manuscript, we demonstrate an all-fiberized, single-frequency and polarization-maintained (PM) amplifiers with wavelength tuned from 1065 nm to 1090 nm. The ASE is suppressed by a signal to noise ratio of higher than 27 dB, and each wavelengths can be amplified to be 250 W output power. The stimulated Brillouin scattering (SBS) effect in such high power amplifiers is suppressed by employing a high dopant fiber (10 dB/m). The polarization extinction ratio (PER) of the amplifier is over 20 dB at the maximum output power. It should be noted that although the experiments are conducted at the wavelength from 1065 nm to 1090 nm with a step of 5 nm, the wavelength can also be continuously tuned.