Semiconductor optical device and method of manufacturing the same

Abstract

A semiconductor optical device includes a substrate having an optical waveguide, a gain section formed of a compound semiconductor having an optical gain and bonded to an upper surface of the substrate, the gain section having a first mesa, and a first wiring line electrically connected to the gain section. The first mesa of the gain section is optically coupled to the optical waveguide. The substrate includes a first layer, a second layer, and a third layer. The first layer has a higher thermal conductivity than the second layer. The second layer is stacked on the first layer. The third layer is stacked on the second layer. A recess provided in the substrate extends through the third layer to the second layer in the thickness direction. The first wiring line extends from the first mesa of the gain section to the recess.