| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical modulator of high efficiency, which can be mounted on an optical communication system. SOLUTION: The optical modulator is formed of a substrate 31 with an electro-optic effect, and is equipped with: an optical waveguide 32 equipped with two branching optical waveguides 32a/b; a modulating electrode 33 having first to third conductor lines 33a-c which are coupled together electromagnetically, and applying a modulating electric field to the optical waveguide; a grounding conductive layer 34 forming first to third microstrip lines with the first to third conductor lines; and an electric signal input section 35 supplying a high frequency signal for optical modulation to the modulating electrode. An inner side edge of the first conductor line 33a is placed directly above the branching optical waveguide 32a, an edge out of edges of the third conductor line 33c opposite to the second conductor line 33b is placed directly above the branching optical waveguide 32b. Electric potentials of identical signs are applied to the first/second conductor lines 33a/b, and an electric potential with a sign different from those of the electric potentials applied to the first/second conductor lines is applied to the third conductor line 33c. COPYRIGHT: (C)2007,JPO&INPIT |
