Semiconductor optical amplifier

Abstract

A semiconductor optical amplifier includes a substrate including a silicon layer, and a gain section formed of a III-V compound semiconductor and having an optical gain, the gain section being bonded to the silicon layer. The silicon layer has a waveguide. The gain section has a mesa at a position overlapping the waveguide. The mesa protrudes in a direction away from the substrate and is located over the waveguide. In a portion of the waveguide overlapping the mesa, a portion of the waveguide close to an input end of the gain section has a smaller cross-sectional area, and a portion of the waveguide close to an output end of the gain section has a larger cross-sectional area.

Dependencies are inferred from the claim text.