Patent ID: 7394104

Claim:
A semiconductor optical device comprising: confinement-conducting regions having semiconductor layers, each of the confinement-conducting regions including one or more material layers; and a gain region having a semiconductor layer, which is formed between the confinement-conducting regions and includes one or more material layers, wherein the confinement-conducting regions and the gain region have a mesa structure, and a lateral portion of at least one of the material layers constituting the semiconductor layers of the confinement-conducting regions and the gain region is recessed, and the recess is formed by selectively etching the lateral portion of at least one of the material layers and the material layers surrounding the recess have different etching rates compared to at least one of the material layers constituting the semiconductor layer of the gain region, and the recess is partially or wholly filled by deposition with an oxide layer, a nitride layer or a combination of them, wherein at least one reflecting mirror is further formed so as to be parallel with the confinement-conducting regions and the gain region such that output light is perpendicular to the confinement-conducting regions and the gain region.