Patent ID: 7561765

Claim:
An optical integrated circuit comprising: a planar lightwave circuit in which an optical waveguide is formed on a first substrate; and a semiconductor element in which at least one element having a semiconductor waveguide is formed on a second substrate, wherein the planar lightwave circuit and the semiconductor element are fixed at one contact surface, and an end of the optical waveguide and an end of the semiconductor waveguide are optically coupled with each other at the contact surface, and an input semiconductor waveguide and an output semiconductor waveguide are formed at an input side and an output side of the element having the semiconductor waveguide, respectively, one of the input and the output semiconductor waveguides has a turnaround portion turned around on the second substrate, and an end of the input semiconductor waveguide and an end of the output semiconductor waveguide are optically coupled at the contact surface with an end of an input side optical waveguide and an end of an output side optical waveguide formed on the first substrate, respectively.