Development of edge pumped Yb:YAG planar waveguide lasers

摘要

A waveguide with 150 μm core height of 2% Yb:YAG between sapphire claddings is core-pumped at 480W by diode bars coupled into the 13 mm long edge-facet. The pump unit has custom correction of collimation errors and lens aberrations. Using a 6mm width and 7° edge-facet angle, power is limited by competing ASE loss or parasitic oscillation along TIR-trapped internal paths, giving 40 W output for stable and 25 W for unstable resonators. Ray-tracing shows a 20° facet angle is necessary to successfully out-couple ASE from the core. Preliminary operation at 90W and an increased threshold for the parasitic oscillation are obtained.