Patent ID: 8457451

Claim:
A semiconductor optical device comprising: a semiconductor substrate having a surface; a mesa structure supported by the surface of the semiconductor substrate and having, in a plan view perpendicular to the surface of the semiconductor substrate, a rectangular shape, with two longer sides, two shorter sides, and four corners, each corner being located at an intersection of one of the shorter sides and one of the longer sides; and four extended mesas supported by the surface of the semiconductor substrate, wherein each extended mesa extends from a corresponding corner of the mesa and is at least partially transverse to the longer sides of the mesa, and the mesa and the extended mesas are continuous and have the same composition; and first and second outside mesas supported by the surface of the semiconductor substrate and located opposite and spaced from respective longer sides of the mesa wherein each of the first and second outside mesas is joined to two of the extended mesas, and the mesas, the extended mesa, and the outside mesas are continuous and have the same composition.