Diffraction limited 195-W continuous wave laser emission at 2.09 µm from a Tm 3+ , Ho 3+ -codoped single-oscillator monolithic fiber laser

We present a bi-directionally 793-nm diode-pumped Tm3+, Ho3+-codoped silica polarization maintaining double-clad all-fiber laser based on a single-oscillator architecture emitting 195 W at 2.09 µm in continuous wave mode of operation, with a beam quality near the diffraction limit (M2 = 1.08). The power scaling of the laser is only pump-power-limited in the range of the total available pump power (540 W).