Reliability of 780-nm High-Power Laser Diodes with Thin Quantum Well Active Layer

Abstract

The reliability of 780-nm-(AlGa)As high-power laser diodes with a thin triple-quantum-well or a single-quantum-well active layer is investigated. The thin active layers achieve high catastrophic optical damage levels above 170 mW. In these laser diodes, a gradual increase of the operation current limits the lifetime of the laser diode. The gradual degradation rate is higher in the single-quantum-well laser diodes than to the triple-quantum-well laser diodes, and is also higher in shorter-cavity-length laser diodes. The power dependence of the gradual degradation rate is very small compared with the dependence on cavity length or active layer structure. The gradual degradation mainly depends on the threshold current density per active layer thickness. As a result, 60-mW reliable operation for more than 1000 hours was achieved at 50°C in 600-µm-length triple-quantum-well lasers.