a first embodiment of a semiconductor laser diode array in accordance with the present invention is illustrated the semiconductor laser diode array generally identified with the reference numeral 20 includes a plurality of submounts 22 formed from an electrically conductive and thermally conductive material as shown the semiconductor laser diode array 20 includes four laser diode bars generally identified with the reference numeral 24 as shown in fig1 each of the laser diode bars 24 is carried and electrically connected along one surface to a submount 22 forming a subassembly in order to reduce stress between the subassemblies flexible compliant or expansion matched spacers 28 are disposed between each of the subassemblies the spacers 28 are flexible compliant or expansion matched and formed from an electrically conductive material as shown the spacer 28 is shown as a foil tube formed from a soft ductile material that is preferably non oxidizing in air such as gold au or other precious metals an additional submount 30 as well as an additional spacer 32 may be provided on the end of the array 20 so that the length of the array matches the length of commercially available backplane coolers in accordance with an important aspect of the invention electrical connection among the various components in the array 20 are by.