InGaAlP/GaAs injection lasers of orangeoptical range ($\sim$600nm)

Lasing in the orange spectral range (599–605 nm) is demonstrated for (Al$_{x}$Ga$_{1-x}$)$_{0.5}$In$_{0.5}$P–GaAs laser diodes grown by metalorganic vapor-phase epitaxy (MOVPE) on GaAs (211)A and (322)A substrates. The active region consists of four layers of In$_{x}$Ga$_{1-x}$P vertically coupled quantum dots. The leakage of nonequilibrium electrons from the active region is suppressed by barriers consisting of four quantum-confinement layers of the InGaAlP solid solution with a high Ga content. The maximal optical output power in the pulsed regime is 800 mW and is limited by the catastrophic optical degradation of mirrors. The lasers fabricated from structures grown on (322)A substrates have a lower threshold current density, higher differential quantum efficiency, and smaller internal losses when compared with lasers fabricated from structures grown on (211)A substrates, which is explained by the higher barrier for nonequilibrium electrons in the first case.