Semiconductor optical device

A semiconductor optical device, comprising:

• a substrate of a first conductivity type;
• a first optical confinement layer of the first conductivity type arranged above the substrate;
• a multi quantum well layer arranged above the first optical confinement layer,
• wherein the multi quantum well layer comprises a plurality of well layers and a plurality of barrier layers;
• a second optical confinement layer of a second conductivity type arranged on the multi quantum well layer;
• and
• a photoluminescence (PL) stabilization layer arranged between the substrate and the multi quantum well layer,
• the PL stabilization layer having a thickness that is half a thickness of the multi quantum well layer or more,
• the PL stabilization layer having a consistent band gap throughout the thickness of the PL stabilization layer, and
• an entirety of the PL stabilization layer having a composition wavelength that is shorter than a composition wavelength of the plurality of well layers, and is longer than a composition wavelength of the first optical confinement layer.