Laser reliability assurance strategies: Part I: Discussion of the background, assumptions, and purposes of the proposed strategies.

We examine various strategies designed to assure the reliability of semiconductor lasers intended for an application in which the design lifetime is long, replacement of redundancy is impractical and the failure of even a few lasers could be crippling. The object is primarily to produce, by some screening procedure, a population of devices whose degradation is exclusively controlled by a tolerably slow-acting mechanism; the object is not how to build reliable lasers. A critical examination of the well- known bathtub and statistical approaches to establish reliability assurance has shown them to be less than optimum for assuring the reliability of a new semiconductor laser structure. We propose an alternative approach which we discuss in schematic form in this paper.