Pair-groove-substrate GaAs/AlGaAs multiquantum-well lasers with a self-aligned stripe geometry

GaAs/AlGaAs multiquantum-well (MQW) lasers with a self-aligned structure incorporating a waveguide and current confinement were fabricated on a substrate with a pair of etched grooves using two-step epitaxial growth. First, a current-blocking layer was grown selectively on the substrate by low-pressure organometallic vapour-phase epitaxy (OMVPE), and then the GaAs/AlGaAs MQW laser structure was constructed on the substrate with the OMVPE layer by molecular-beam epitaxy. The mesa-shaped part of the active layer above the current-confinement region provides a lateral refractive-index optical waveguide. The lasers show well controlled transverse-mode oscillations with low threshold currents.