Patent ID: 7263251

Claim:
An optical switch having a branched-type interferometer structure, comprising: a photonic crystal structure having at least first and second optical media with different refractive indices where the second optical medium is regularly arranged in the first optical medium to form a alternately structure at least on a two-dimensional plane, wherein the photonic crystal structure has a region as a waveguide where the second optical medium is replaced by the first optical medium for a width of at least a single line, and wherein the single waveguide extending from the input end branches into two branch waveguides at a first Y-shaped junction, which are recombined into a single waveguide again at a second Y-shaped junction and extends to the output end, each branch waveguide having an electrode, and wherein the refractive index of the photonic crystal structure changes and the output of an optical signal of the light incident to the input end is switched on and off by making the optical signals between the two waveguides to be in phase or by causing phase difference therebetween by subjecting the electrodes corresponding to the two branch waveguides of the optical paths to current injection, application of a reverse bias voltage or radiation of control light other than the incident light.