Abstract :
The fabrication and characteristics of a high-power GaAs injection laser for room-temperature operation are described. A single laser emits 70 watts peak power from one facet at four times the threshold current. The diodes are fabricated from epitaxial wafers prepared by the solution-growth process. Scaling from work on low-power (7-watt) units to this high power has been accomplished by increasing the junction width, which requires general improvement in the crystalline quality and in the control of the doping. Data are given on the effect of doping density, crystal quality, and imperfections near the junction, as well as junction width. The reduced yield in high-power diodes, of which only one-third from a single batch give the desired output, is associated with filamentary lasing and with super-radiant walk-off modes, neither of which is under full control. Preliminary data on life tests show that long-lived units can be made, but that apparently identical units from the same batch show wide variations in the rate of degradation.
