Patent ID: 7302140

Claim:
An optical switch comprising: a substrate which has at least partial conductivity; an optical waveguide layer which is formed on the substrate, the optical waveguide layer including an incident-side channel waveguide, having a centerline and an outgoing side, on which a light signal is incident and a plurality of outgoing-side channel waveguides, each having a centerline and an incident side, and branching from the incident-side channel waveguide; and a control electrode having a waveguide side which is formed on a crossover portion of the plurality of the outgoing-side channel waveguides of the optical waveguide layer, the control electrode forming, near the crossover portion of the plurality of outgoing-side channel waveguides, a reflection plane which reflects the incident light signal by applying a voltage to the optical waveguide layer to control the refractive index of the optical waveguide layer, and the control electrode switches propagation paths of the light signal, wherein a taper portion which broadens out in the propagation direction of the light signal is formed on the outgoing side of the incident-side channel waveguide, and the taper portion is connected to the incident side of the plurality of the outgoing-side channel waveguides through a coupling portion, wherein a reverse taper portion which narrows in the propagation direction of the light signal is formed on the incident side of the plurality of the outgoing-side channel waveguides.