Abstract
Correlations between degradation and device characteristics are investigated in InGaAsP/InP buried heterostructure lasers. The logarithm of threshold-current increase rates is confirmed to be proportional to the voltage decrease at low current when injected carrier lifetime decreases during aging. When leakage current increases during aging, devices having a low initial voltage also tend to degrade to a large extent. These correlations hold within an operating range limited by the device structure and the material used during fabrication.