Dual-wavelength AlGaAs/GaAs laser by selective removal of a quantum well in an asymmetric dual quantum well structure

The longer-wavelength quantum well in an AlGaAs/GaAs asymmetric dual quantum well laser structure was selectively removed by localized intermixing. High Si doping on each side of the longer-wavelength well caused intermixing during an anneal under a SiNx cap, while leaving the other nearby well intact. During an anneal under an exposed GaAs surface layer, both quantum wells remained intact. By patterning the surface with alternating SiNx and exposed GaAs, the longer-wavelength quantum well was selectively intermixed. Integrated broad area lasers were fabricated with threshold current density and external quantum efficiency of 260 A/cm2 and 30%/facet at a wavelength of 751 nm in capped regions and 195 A/cm2, 32%/facet at 824 nm in the uncapped regions.