Optical waveguide and optical module using the same
An optical waveguide contains a core layer in which light is transferred, and a cladding layer that clads the core layer. The core layer has an inclined end surface across a direction where the core layer extends. The inclined end surface reflects light from the core layer to outside or light from the outside to the core layer. The cladding layer has an end portion that extends to the inclined surface of the core layer. The cladding layer includes a system that prevents an adhesive agent from flowing out.
1. An optical waveguide comprising:
a core layer through which light is transferred;
an inclined edge at an end of said core layer the inclined edge reflecting light from the core layer to outside or light from the outside to the core layer; and
a cladding layer comprising a buffer-cladding layer, an undercladding layer and an overcladding layer that clads the core layer,
wherein,
said cladding layer has at least one fiber guide groove,
an optical fiber inserted in said fiber guide groove and aligned with said core layer, and
said overcladding layer includes an end portion which extends to the inclined edge of said core layer and along the incline surface forming a stepwise portion having a height equal to or greater than a projected portion of said optical fiber that prevents an adhesive agent from flowing out of an upper surface of said overcladding layer.
2. The optical waveguide according to claim 1 wherein the stepwise portion has a width of about 30 μm.
3. The optical waveguide according to claim 1 wherein the optical waveguide is made of polymer material.
4. An optical module comprising a board and an optical waveguide on the board, said optical waveguide further comprising:
a core layer through which light is transferred;
an inclined edge at an end of said core layer, the inclined edge reflecting light from the core layer to outside or light from the outside to the core layer; a cladding layer comprising a buffer-cladding layer, an undercladding layer and an overcladding layer that clads the core layer;
an optical element that receives or emits the light on the board under the optical waveguide opposite to the inclined edge of the core layer in the optical waveguide; and
a holding member that holds the optical waveguide; and
an adhesive agent that bonds said holding member to said cladding layer,
wherein,
said cladding layer has at least one fiber guide groove,
an optical fiber inserted in said fiber guide groove and aligned with said core layer, and
said overcladding layer includes an end portion which extends to the inclined edge of said core layer and along the incline surface forming a stepwise portion having a height equal to or greater than a projected portion of said optical fiber that prevents an adhesive agent from flowing out of an upper surface of said overcladding layer.
5. The optical module according to claim 4 wherein the holding member covers the optical fiber that is inserted into the fiber guide groove,
the optical waveguide touches said optical fiber and is close to the inclined edge of the core layer in the optical waveguide.
6. The optical module according to claim 4 wherein the optical waveguide is made of polymer material.