Integration of laser sources into optoelectronic integrated circuits requires that the laser do not operate using two cleaved end facets. Unfortunately, replacing of one of the end facets results by either a dry etched mirror or by a corner reflectors results in undesirable performance of the laser source since a gain coefficient for the laser source is lower than that for a dual cleaved end facet laser source. A modified waveguide is thus proposed which serves to reduce the undesirable effects found when a corner reflector is used by providing an improved waveguide region between the cleaved end facet and the corner reflector that facilitates excitation of a single optical mode within a laser cavity formed between the corner reflector and the cleaved end facet.