| 摘要 |
The purpose of the present invention is to provide an optical modulator in which, even in a case where optical waveguides and a control electrode are highly integrated, strain due to stress acting on the optical waveguides from the disposed wiring of signal electrodes is mitigated, and the generation of temperature drift and the like is suppressed. Provided is an optical modulator comprising a substrate 1 which has an electro-optical effect, optical waveguides (L1-L4) which are formed on the substrate and which include at least one Mach-Zehnder optical waveguide, and a control electrode for controlling optical waves propagated along the optical waveguides, wherein the optical modulator is characterized by the following: the control electrode is constituted by signal electrodes (S1, S2) and ground electrodes (G1-G3); the signal electrodes are provided with input/output pads (S1P, S2P) which are electrically connected to electrical circuits that are disposed outside of the substrate, a reciprocal-action section (arrow R1) in which an electric field is caused to act on the optical waveguides, and a wiring section which connects the pads and the reciprocal-action section; in the extending direction (width direction in fig. 3) of the Mach-Zehnder optical waveguide, a portion of the wiring is disposed parallel to such extending direction, within the range (arrow R2) in which present are two branching waveguides that constitute the Mach-Zehnder optical waveguide; and at a position which has line symmetry with a portion of the wiring, with respect to the central axis of symmetry of the extending direction of the Mach-Zehnder optical waveguide, formed is a portion of the reciprocal-action section, another portion of the wiring, or a stress-relieving structure for the ground electrodes. |
