Open AccessEfficient KY_1-x-yGd_xLu_y(WO_4)_2:Tm^3+ channel waveguide lasers
Author(s) -
K. van Dalfsen,
S. Aravazhi,
Dimitri Geskus,
Kerstin Wörhoff,
Markus Pollnau
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.005277
Subject(s) - materials science , laser , optics , cladding (metalworking) , wavelength , slope efficiency , epitaxy , waveguide , dielectric , optoelectronics , fiber laser , layer (electronics) , physics , metallurgy , composite material
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%.