Abstract: A heterostructure laser diode is provided with an active region that includes a ternary or quaternary semiconductor compound. The composition of the semiconductor compound forming the active region is modulated resulting in an active region with a modulated strain profile (.increment.a/a), e.g., a triangular sawtooth-like strain profile, perpendicular to the laser diodes epitaxial layers, i.e., parallel to the z-axis. This permits the present invention to increase strain and avoid formation of misfit dislocations by compensation, i.e., by inserting strained layers having opposing strains.