| 摘要 |
PROBLEM TO BE SOLVED: To suppress discharge of electric charge accumulated in a substrate of an optical modulator or in the vicinity thereof.SOLUTION: An optical modulator comprises: a ferroelectric substrate on which first and second branch optical waveguides are formed; a signal electrode formed in the vicinity of at least one of the first and second branch optical waveguides; a first electrode formed in the vicinity of the first branch optical waveguide, to which a first DC voltage is applied; a second electrode formed in the vicinity of the second branch optical waveguide, to which a second DC voltage is applied; a third electrode electrically connected to the first electrode and formed at both sides of the second electrode; and a fourth electrode electrically connected to the second electrode and formed at both sides of the first electrode. A first gap between the first electrode and the fourth electrode is almost the same with a second gap between the second electrode and the third electrode. A gap between the third electrode and the fourth electrode is one amount or 2-5 times as large as the first gap.SELECTED DRAWING: Figure 7 |
