Patent ID: 8805131

Claim:
An optical module comprising: an optical waveguide that transmits and outputs signal light; a circuit board that transmits the signal light output from the optical waveguide, and includes a low refractive-index portion that neighbors and surrounds a transmissive portion and has a lower refractive index than the transmissive portion, which transmits the signal light; and a light-receiving element that includes, on a side toward the circuit board, a light-receiving portion that receives the signal light that has transmitted through the circuit board, wherein the signal light is reflected toward the light-receiving element at a boundary surface between the transmissive portion and the low refractive-index portion, the circuit board includes a ground electrode at a surface on a side opposite of a circuit board surface toward the light-receiving element, the low refractive-index portion is provided up to a bottom of the circuit board, and the transmissive portion is fixed by the ground electrode provided on the circuit board.