Packaging and performance of high power semiconductor lasers of high heat flux up to 2000 W/cm/sup 2/

Abstract

High power broad area semiconductor lasers have found increasing applications. Compared to low power narrow-stripe semiconductor lasers, packaging including the assembly design, process and thermal management, has much higher impact on the output power and reliability of high power broad area lasers which generate more heat and have high heat flux. In this paper, we first introduce the package structures and assembling process of high power broad area lasers. We report two types of high power broad area laser assemblies. One is a microchannel liquid cooled assembly and the other is a conduction cooled CT-mount assembly. The performances including output power, thermal behavior and far fields are presented. The measurement results showed that excellent thermal management through package structure design as well as quality die attachment is the key in not only improving output power, but also significantly improving beam divergence and far field distribution. The reliability of indium solder bonded and AuSn solder bonded CT mount assemblies were evaluated. The results showed that the die attach solder can significant impact the reliability of high power broad area lasers and that indium solder is not suitable for high power laser applications due to electromigration at high current densities and high temperatures.