Laser structures for different operating temperatures were developed. Higher temperatures need an increase in barrier height to reduce carrier leakage. Best results for an emission wavelength of approximate to 800 nm were obtained using an asymmetric structure containing an n-InGaP and a p-Al0.5Ga0.5As waveguide. Such structures show 10 W output power for a single laser diode and > 100 W for a laser bar at 50 degrees C ambient temperature and also a good aging behavior. Lower operating temperatures permit lower barrier heights which results in a lower series resistance and therefore higher conversion efficiency at high power. Carrier concentration and mobility for different AlxGa1-xAs compositions were estimated in dependence on temperature. An optimized structure reached 20 W for a single laser diode and 2 kW for a laser bar in QCW mode at -70 degrees C. (C) 2016 Elsevier B.V. All rights reserved.