Low-threshold room-temperature cw operation of (AlGaAs)m(GaAs)n superlattice quantum well lasers emitting at ∼680 nm

Low cw threshold current of 45 mA and high differential quantum efficiency of 78% have been achieved at room temperature in an (Al0.6Ga0.4As)2(GaAs)2 superlattice quantum well laser emitting at 681 nm. The quantum well structure has been optimized to minimize the threshold current density at 680 nm. The new ridge-waveguide structure with a current-blocking supporting region is employed to reduce the thermal resistance.