All-fiber, single-mode spectral beam combining of high power Tm-doped fiber lasers

Signal beam combining of Tm-doped fiber lasers can increase the laser output power while simultaneously maintaining the single mode beam quality. We demonstrate an all-fiber integrated dual-wavelength Tm-doped fiber laser with an output power of 36 W by using the spectral beam combining method. The constituent lasers are operating at the wavelengths 1949 and 1996 nm and an in-house-made WDM is used for combination of these two different wavelengths. All-fiber truly single mode power combining is demonstrated for the first time in this wavelength region.