Reducing thermal resistance of high-power semiconductor diode lasers with coupled waveguides

Thermal resistance of diode lasers with different waveguide designs has been investigated. Coupled large optical cavity (CLOC) design allows reducing internal loss and heterostructure thermal resistance of high-power InGaAs/ GaAs/AlGaAs laser diodes due to the thinned p-claddings and the active region located close to the wafer p-side. Using a simple model we have calculated the thermal resistance of the heterostructure of broad-area lasers and compared the CLOC design with the reference one as well as with some of the best designs of present-day high-power lasers. The improved measurement technique has enabled us to measure reducing of thermal resistance associated with optimization of the laser wafer design. The experimental data are in good agreement with the calculations. A combination of the broadened waveguide, low internal loss and thermal resistance has resulted in good high-power performance of CLOC lasers.