Precise Facet Temperature Distribution of High Power Laser Diodes: Unpumped Window Effect

A thermoreflectance technique is used to evaluate the temperature variations at the output facet of high power GaAs-based laser diodes emitting at 980nm. Two kinds of diodes with different unpumped windows (UPW) are studied to determine the influence of the UPW length on the temperature variation. We show that in the vicinity of the active region, where a catastrophic optical damage (COD) is most susceptible to occur, the short UPW diode heats much more (up to 40%) than the long UPW one.