3 kW polarization maintained fiber lasers with 10.6 GHz linewidth and near diffraction limited beam quality

In this work, a high-power polarization-maintained fiber laser with ultra-narrow linewidth and near diffraction limited beam quality is demonstrated. The stimulated Brillouin scattering is mitigated by optimizing phase modulation scheme, the mode instability is suppressed by coiling the active fiber, and the output power reaches to 3kW at the full width at half-maximum linewidth of 10.6GHz. At maximum output power, the stimulated Raman scattering suppression ratio reaches to 75dB, the polarization extinction ratio is 96%, the beam quality M2 is 1.156, and the further scaling of output power is limited by stimulated Brillouin scattering effect. To the best of our knowledge, this is the highest power for polarization-maintained fiber laser with about 10GHz linewidth ever reported so far.