Reliability evaluation on 100W QCW-AlGaAs/GaAs 808nm cm-bars

Abstract

ABSTRACT Degradation performance and lifetimes of high power laser diodes are important issues for laser manufacturers and end users. To fully understand these issues we have set up a computer controlled diode array reliability experiment which can automated monitor the laser bars 24 hours a day. Subsequent two different temperatures aging tests were completed, according to the aging results we obtained an acceleration factor 1.88 of resulting in a thermal activation energy of E a =0.21eV. Finally, the detailed failure analysis for the failed devices and its influence on reliability were reported on this paper. Keywords: Laser diodes, reliability, degradation, aging test, failure analysis 1. INTRODUCTION The broad industrial application of high power laser diode ar rays started more than ten years ago. Laser diode arrays are used directly in materials processing, medicine, display, or printing systems, but also as pump sources for various rod, disk, and fiber lasers. In the last few years we see an increasing demand in high power laser diode arrays and a constant development towards high output powers per laser bar. For industrial applications, the reliability is rated as the key parameter deciding about the more or less extensive use of high power laser diode arrays in future. Its importance is even higher than the achievement of new records in the optical output power of laser bars. Evaluation of the reliability of a laser diode arrays has a cost associated with it. The most common method used to evaluate the lifetime of high power laser diodes is to perform aging tests, which is consist of checking, for example, the percentage decrease in the optical output power over a number of operating hours and determining or extrapolating when the lase r bar will die. This method requires vast costs. The possibilit y of reducing the number and duration of aging tests or even avoiding them toge ther is of great interest because it would allow significant cost reductions. In this paper, we present the results of long-time aging tests, acceleration factors, and ther mal activation energies for high power 808nm laser bar. Extensive studies have been done to understand some main failure mechanisms such as mechanical stress damage, facet degradation and solder migration. We will discuss these mechanisms including their causes, failure characteristics and its influence on device reliability. Based on this, we discuss the failure prediction methods of high power laser bars.