High-power low-threshold graded-index separate confinement heterostructure AlGaAs single quantum well lasers on Si substrates

Abstract

A high-power low-threshold graded-index separate confinement heterostructure AlGaAs single quantum well laser on Si substrates has been demonstrated for the first time by a hybrid growth of migration-enhanced molecular beam epitaxy followed by metalorganic vapor phase epitaxy. The quantum well laser showed an output power of more than 400 mW per facet under pulsed conditions. A room-temperature threshold current of 300 mA was obtained with a differential quantum efficiency of 40% without facet coating. The threshold current density was 550 A/cm2 for a cavity length of 500 μm. These results show the highest peak power reported to date for low-threshold lasers on Si substrates. The full width at half maximum of the far-field pattern parallel to the junction was 6°. Threshold current densities as low as 250 A/cm2 were obtained for lasers on GaAs substrates.