| 摘要 |
There is provided an optical circuit including a plurality of optical wave guides each composed of electro-optic crystal such as LiNbO3, or LiTaO3 and each designed to have a domain orientation different from each other. In accordance with the present invention, a portion of an optical device is inverted with respect to a domain. For instance, in an optical wave guide having a domain-inverted portion, if electric fields having the same orientation are applied to a plurality of portions which are to vary an index of refraction thereof, indexes of refraction are caused to vary in opposite polarities. Hence, it is possible to lower a voltage at which an optical device operates. For instance, if the present invention is applied to a Mach-Zehnder type phase shifter, it would be possible to accomplish push-pull operation, only if an electric field having one orientation is applied thereto. In addition, it is possible to further lower a voltage at which the phase shifter operates, by making a difference in an index of refraction between two optical wave guides.
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