160W narrow-linewidth fiber laser with a homemade polarization-maintaining Tm-doped fiber

High-power narrow-linewidth linearly-polarized Tm-doped fiber lasers operating at 2.0μm have attracted extensive interest in both scientific and industrial fields such as free space communication, remote laser sensing, coherent Doppler lidar wind detection, and gravitational wave detection. In this work, an output power of 160 W narrow-linewidth linearly polarized fiber laser operating at 2007.6 nm was realized by employing a homemade polarization-maintaining Thulium-doped fiber (PMTDF), corresponding to a slope efficiency of 45% and a 3 dB linewidth of 73 pm. The PMTDF was manufactured by modified chemical vapor deposition (MCVD) method combined with solution doping technology, with core and cladding sizes of 25 μm and 400 μm, respectively. The numerical aperture (NA) of the PMTDF is 0.1 and the cladding absorption is 4 dB/m at 793 nm. During the power scaling, the polarization extinction ratio (PER) maintained higher than 16.5 dB, indicating an excellent polarization maintaining performance of the manufactured fiber. The stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) effects were well-suppressed. This work could provide a good reference for the further power scaling of narrow-linewidth linearly polarized fiber lasers operating at 2.0 μm.