Optical module

An optical module comprising:

• an electric circuit board comprising a light-permeable resin substrate and an electric circuit provided on a front surface of the light-permeable resin substrate;
• and
• an optical element joined onto a front surface of the electric circuit board,
• with a light-emitting or light-receiving portion of the optical element facing an electric circuit surface side of the electric circuit board, the optical element is joined to the electric circuit board via a bump,
• wherein a space between the light-emitting or light-receiving portion of the optical element and the light-permeable resin substrate is filled with a light-permeable resin cured material so that the entire surface of the bump is covered with the light-permeable resin cured material,
• wherein a relative refractive index difference between the light-permeable resin cured material and the light-permeable resin substrate is not greater than 20%,
• wherein an optical waveguide is provided on a back surface of the light-permeable resin substrate opposite from a surface thereof to which the optical element is joined,
• wherein the optical waveguide comprises a first cladding layer, a core, and a second cladding layer,
• wherein a first end portion of the optical waveguide corresponding to the optical element is formed into a light reflecting surface, and
• wherein the light-emitting portion or the light-receiving portion of the optical element is optically coupled to the core by using the light reflecting surface of the optical waveguide.