Failure mechanism analysis for a state-convertible SLD failure mode

Abstract

Super luminescent diodes (SLDs) have wide spectrum and high output optical power, which are widely used in area of optical fiber sensing, optical coherence tomography (OCT) and fiber optic gyroscope (FOG), etc. As a high power light source, its failure analysis is of great significance to improve its reliability especially for field use. In this paper, we introduced a special failure mode we found in a nondestructive failure analysis process for failed SLDs, and our mechanism analysis about it. When we used an adjustable constant current source circuit to perform an electrical test on two failed SLDs, a state-convertible SLD failure mode was found. The failure mode can be represented by voltage-current and voltage-time curve of the SLDs. The failed SLDs show to have two different failure states, i.e. resistive state and illuminating state. And the SLDs can transfer from one state to another state by applying certain voltages. To explain this phenomenon we proposed a failure mechanism based on assumption of movable ions in crystal defect and induced-channel effect.