Proton irradiation effects on multi-quantum-well laser diodes and their annealing characteristics

The effects of 5 MeV and 2 MeV proton irradiations on multi-quantum-well laser diodes with Fabry-Perot cavity and distributed feedback are investigated. It is found that the threshold current and total current at low voltage range of current-voltage characteristics curves increase gradually at the fluence level from 5×1012 cm-2 to 5×1013 cm-2. The damage mechanism is attributed to the displacement effect of protons with the help of 60Coγ total dose experiment. Trim program simulation shows that the number of vacancies induced by 2 MeV protons is more than that induced by 5 MeV protons and so does the threshold current. Due to forward-bias-induced annealing effects, the laser diode biased during irradiation is less degraded than that short-circuited, and annealing curves can b