Abstract: An improved semiconductor injection laser diode array having reduced interaction between the elements of the array. The array comprises a substrate, an active layer and a capping layer with a separate electrical contact to the capping layer for each element of the array and a common electrical contact to the substrate. The reduced interaction is obtained by regions of higher electrical conductivity extending through the substrate towards the p-n junction from those portions of the substrate surface opposed to the contacts to the capping layer and by separate electrical contacts to each of these higher conductivity regions. The higher conductivity regions provide a lower resistivity path for current flowing through the p-n junction, thus reducing current spreading.