Low thermal expansion coefficient cooler for diode-laser bar

摘要

A heat sink for cooling a diode-laser bar on a gallium arsenide (GaAs) substrate includes a water-cooled copper body. A layer of a metal having a coefficient of expansion (CTE) about equal to or greater than that of gallium arsenide but less than that of copper is bonded to each of two opposite surfaces of the body. A layer of copper is bonded each of the lower-CTE layers. The copper layers each have a thickness less than that of the lower-CTE layers and are under tensile strain. This provides that when a GaAs diode-laser bar is soldered to the heat sink the copper layers do not expand any more than the lower-CTE layers differential expansion between the copper and the lower CTE material merely reduces the tensile strain in the layers.