Annealing effects on multi-quantum well laser diodes after proton irradiation

The threshold current of multi-quantum well laser diodes increased by about 1.5 mA at a proton fluence of 6/spl times/10/sup 12/ p/cm/sup 2/. It recovered gradually due to forward-bias annealing at I/sub bias/=35 mA and became about 0.8 mA less than before irradiation after 86 h of forward bias annealing. At the same time, the optical power at a given bias became greater than before irradiation. There is a fast recovery during the first 100 s after proton irradiation. Increasing the forward bias current during annealing speeds up the annealing process. The degradation of optical power at a proton flux of 1.87/spl times/10/sup 9/ p/cm/sup 2//s (4.7% at a fluence of 6/spl times/10/sup 12/ p/cm/sup 2/) is less than that at a proton flux of 1.45/spl times/10/sup 10/ p/cm/sup 2//s (10.5% at a fluence of 6/spl times/10/sup 12/ p/cm/sup 2/) due to the in-situ forward-bias annealing effects.