Optical waveguide and method of manufacturing the same, and method of manufacturing optical/electrical hybrid substrate

A method of manufacturing an optical waveguide including an optical waveguide main body having a first region for transmitting a light signal, and a second region arranged on both sides of the first region and not contributing to a transmission of the light signal, the method comprising:

• (a) forming a first cladding layer on a metal plate in the first region;
• (b) forming a metal film on the metal plate in the second region such that a thickness of the metal film is substantially equal to a thickness of the first cladding layer;
• (c) forming a core material to cover upper surfaces of the first cladding layer and the metal film;
• (d) forming simultaneously a core portion, alignment marks and a first through hole by patterning the core material, said first through hole passing through the core material in the second region;
• (e) forming inclined surfaces on the core portion by cutting the core portion based on the alignment marks;
• (f) forming mirrors on the inclined surfaces of the core portion;
• (g) forming a second cladding layer having a second through hole opposing to the first through hole;
• (h) removing the metal plate and the metal film;
• and
• (i) forming through vias in the first through hole and the second through hole, said through vias being connected to a terminal of a light emitting element and a terminal of a light receiving element.

A method of manufacturing an optical/electrical hybrid substrate including an optical waveguide and a built-up structure including an insulating layer, vias and wirings, said optical waveguide including an optical waveguide main body having a first region for transmitting a light signal, and a second region arranged on both sides of the first region and not contributing to a transmission of the light signal, the method comprising:

• (a) forming a first cladding layer on a metal plate in the first region;
• (b) forming a metal film on the metal plate in the second region such that a thickness of the metal film is substantially equal to a thickness of the first cladding layer;
• (c) forming a core material to cover upper surfaces of the first cladding layer and the metal film;
• (d) forming simultaneously a core portion, alignment marks and a first through hole by patterning the core material, said first through hole passing through the core material in the second region;
• (e) forming inclined surfaces on the core portion by cutting the core portion based on the alignment marks;
• (f) forming mirrors on the inclined surfaces of the core portion;
• (g) forming a second cladding layer having a second through hole opposing to the first through hole;
• (h) forming through vias in the first through hole and the second through hole, said through vias being connected to a terminal of a light emitting element and a terminal of a light receiving element.
• (i) forming the built-up structure on the optical waveguide;
• and
• (j) removing the metal plate and the metal film.

An optical waveguide, comprising:

• an optical waveguide main body comprising:
• a first cladding layer facing at least one of a light emitting element and a light receiving element;
• a second cladding layer;
• and
• a core portion for transmitting a light signal and provided between the first cladding layer and the second cladding layer;
• and
• mirrors for reflecting the light signal;
• and
• wherein the optical waveguide main body has:
• a first region in which the core portion and the mirrors are arranged and the light signal is transmitted;
• and
• a second region arranged on both sides of the first region and not contributing to a transmission of the light signal,
• wherein through vias that pass through the optical waveguide main body are provided in the second region, and the through vias are connected to a terminal of the light emitting element or a terminal of the light receiving element,
• wherein the first region on a side that faces the light emitting element or the light receiving element is protruded larger than the second region on a side that faces the light emitting element or the light receiving element, and
• wherein the through vias are directly connected to a terminal of the light emitting element or a terminal of the light receiving element.