Patent ID: 7668409

Claim:
An optical device comprising: a substrate which has electro-optical effect; an optical waveguide which is formed in the substrate; a branching section which branches an input light to the optical waveguide; a phase controller which controls a phase relation between a first light and a second light, which are branched by the branching section; a coupler which couples the first light and the second light after the control of the phase relation, the coupler outputting a third signal light in which intensity is periodically changed and a fourth signal light in which the intensity is periodically changed and a signal phase of the fourth signal light is different from that of the third signal light; a phase adjuster which gives propagation distance difference to the third signal light and the fourth signal light to adjust the signal phase of the third signal light and the signal phase of the fourth signal light to the same phase, the phase adjuster outputting a fifth phase adjusted light and a sixth phase adjusted light; an optical modulator which performs modulation using the fifth phase adjusted light and the sixth phase adjusted light; and a electrodes that make up the phase controller, the phase adjuster, and the optical modulator.