High‐power tunable operation of AlGaAs/GaAs quantum well lasers in an external grating cavity

Data are presented on operation of 100 μm aperture gain‐guided single quantum well laser diodes in an external grating cavity. A maximum power of 550 mW is coupled out of the cavity with an efficiency of 0.51 W/A. The laser emission has a linewidth of ≲1 A and is tunable from 7950 to 8450 A for the specific laser diodes used in this study. The output beam is collimated in the direction perpendicular to the p‐n junction, and exhibits a divergence of 0.4° parallel to the p‐n junction.