Patent ID: 7230276

Claim:
A semiconductor optical device comprising: a first semiconductor layer of a first conductivity type which is formed on a semiconductor substrate and includes one or more material layers; a second semiconductor layer which is formed on the first semiconductor layer and includes one or more material layers; and a third semiconductor layer of a second conductivity type which is formed on the second semiconductor layer and includes one or more material layers, wherein one or more layers among the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer have a mesa structure, a lateral portion of at least one of the material layers constituting the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer is recessed, and the recess is partially or wholly filled with an oxide layer, a nitride layer or a combination of them, and the first semiconductor layer and the third semiconductor layer serve as confinement-conducting regions, and a layer including a tunnel junction is further formed in one of the confinement-conducting regions.