Reliability of planar waveguide photodiodes for optical subscriber systems

This paper investigates the degradation mode and reliability of planar waveguide photodiodes (WGPD´s) for the optical hybrid module for subscriber systems. From electroluminescence topography observations and current-voltage characteristics, it is clarified that the degradation mode for early failure is caused by the concentration of electric field or a microplasma at the edge of p-n junction. The condition for screening the devices likely to fail early without a bias-temperature test is determined by investigating the degradation mode. From optical beam induced current images, it is clarified that wear-out degradation, which governs the lifetime of WGPD´s, occurs at the p-n junction perimeter on a cleaved facet. Estimation of activation energy, extrapolated lifetime under a practical use condition, and failure rates for wear-out and random failure show that the WGPD has sufficient reliability for optical subscriber systems