High power linearly polarized narrow linewidth fiber laser

Spectral beam combining technology based on diffraction grating is an effective method to obtain tens of thousands of watts or even hundreds of thousands of watts of high-power and high beam quality laser. The high power linearly polarized narrow linewidth fiber laser is an ideal sub-beam source in spectral beam combining systems. Limited by stimulated brillouin scattering and mode instability, the power increase of narrow linewidth lasers has been limited, especially in linear polarization systems. In this paper, we report a high-power line polarized narrow line width fiber laser. The white noise signal (WNS) phase modulation and the pseudo-random binary sequence (PRBS) phase modulation were combined to widen the single-frequency laser line width, and then the three-stages fiber amplifier was used to amplify the narrow-line width laser for power. A high power line polarized narrow line width laser with a center wavelength of 1064nm, a power of 2070W and a 3dB line width of 23GHz was finally obtained. The laser polarization extinction ratio is greater than 14dB.