Abstract: In a multiple optical waveguide device, a transparent plate is bonded or joined on the top surface of a clad with which optical circuits and quartz glass substrates are covered, and optical reflection film is provided on the fringing area or the whole area of a joint surface of the transparent plate with the clad. Optical circuits or waveguide patterns can be recognized easily by visual inspection.

Abstract: A waveguide type optical branching device having: two input ports; two output ports; optical waveguides extending from the input ports and the output ports respectively; and a coupling portion formed allowing the optical waveguides from the input ports and the output ports to gradually approach each other in a direction toward the output ports. The device is operable such that, in a direction from the input ports to an output end of the coupling portion, when light is inputted to one input port of the two input ports, an even more is predominantly excited, and when light is inputted to the other input port of the two input ports, an odd mode is predominantly excited. The optical waveguides in the coupling portion have a core width that is larger at a middle position in a height direction thereof than at an upper surface of the core.

Abstract: A waveguide type optical branching device having: two input ports; two output ports; optical waveguides extending from the input ports and the output ports respectively; and a coupling portion formed allowing the optical waveguides from the input ports and the output ports to gradually approach each other in a direction toward the output ports. The device is operable such that, in a direction from the input ports to an output end of the coupling portion, when light is inputted to one input port of the two input ports, an even more is predominantly excited, and when light is inputted to the other input port of the two input ports, an odd mode is predominantly excited. The optical waveguides in the coupling portion have a core width that is larger at a middle position in a height direction thereof than at an upper surface of the core.

Abstract: In a multiple optical waveguide device, a transparent plate is bonded on the top surface of a clad with which optical circuits and quartz glass substrates are covered, and optical reflection film is provided on the fringing area or the whole area of the transparent plate. Optical circuits or waveguide patterns can be recognized easily by visual inspection.