title: Efficient KY1-x-yGdxLuy(WO4)2:Tm3+ channel waveguide lasers.
abstract: Gd3+(29.5%)-Lu3+(29.0%)-Tm3+(1.5%) co-doped KY(WO4)2 layers were grown onto KY(WO4)2 substrates by liquid-phase epitaxy. Ridge-type channel waveguides with a thickness of 6.6 μm and a width of 7.5-12.5 μm were microstructured 1.5 μm deep by Ar+-beam milling and overgrown with pure KY(WO4)2 as a cladding layer. An upper limit of ~0.11 dB/cm for the waveguide propagation loss at the laser wavelength was determined. Laser experiments with butt-coupled dielectric mirrors demonstrated maximum output powers of 149 mW and 76 mW and slope efficiencies of 31.5% and 17.0% when pumping at 794 nm and 802 nm in TM and TE polarization, respectively. The lowest threshold was 7 mW. The laser wavelength was found to shift from 1930 nm via 1906 nm to 1846 nm for outcoupling efficiencies from 2% via 8% to 2×8%.
authors: Integrated Optical MicroSystems Group, MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. k.vandalfsen@utwente.nl
authors: K
authors: K
authors: van Dalfsen
authors: S
authors: S
authors: Aravazhi
authors: D
authors: D
authors: Geskus
authors: K
authors: K
authors: Wörhoff
authors: M
authors: M
authors: Pollnau