Detection and localization of degradation damaged regions in 1.3 μm laser diodes on InP using low-coherence reflectometry

We report here on the high potential of low-coherence reflectometry, a basically nondestructive technique, to detect and to localize spatially the degradation damaged regions in ∼1.3 μm laser diodes on InP. Using ∼1.3 μm low-coherence probe, three Fabry–Perot lasers with identical active regions (compressively strained multi-quantum wells) and exhibiting different degradation behaviors are investigated. The degradation induced modifications in the optical and electrical activity of the laser cavities are monitored by recording reflectograms both with and without carrier injection. This methodology gave precise information to detect and spatially localize the damaged regions in the cavities of degraded lasers.