In-band pumped Tm,Ho:LiYF 4 waveguide laser

A 4.5 at.% Tm, 0.5 at.% Ho:LiYF planar waveguide (thickness: 25 μm) grown by Liquid Phase Epitaxy is in-band pumped by a Raman fiber laser at 1679 nm (the H → F Tm transition). A continuous-wave waveguide laser generates a maximum output power of 540 mW at 2051nm with a slope efficiency of 32.6%, a laser threshold of 337 mW and a linear laser polarization (π). This represents the highest output power extracted from any Tm,Ho waveguide laser. No parasitic Tm colasing is observed. The waveguide propagation losses are determined to be as low as 0.19 dB/cm.