Strain-engineered cladding layer for optimized active region strain and improved laser diode performance

A laser diode, comprising:

• a semiconductor substrate having a material composition with a first lattice constant;
• and
• a plurality of epitaxy layers formed on the semiconductor substrate, the plurality of epitaxy layers including a waveguide layer and cladding layers, wherein the waveguide layer includes an active region having a material composition associated with a target optical wavelength, wherein a second lattice constant of the material composition of the active region is different than the first lattice constant, and wherein the cladding layers consist essentially of Al, Ga, As, and P;
• wherein a material composition of an individual one of the cladding layers imparts a stress field on the active region;
• wherein the individual one of the cladding layers includes a strain adjusting material, and
• wherein the individual one of the cladding layers includes two or more sublayers in which an average concentration of the strain adjusting material in one of the sublayers is different than an average concentration of the strain adjusting material in a different one of the sublayers.