| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide device capable of reducing propagation loss of optical waves and preventing optical response properties from deteriorating in a high frequency range using propagation loss reduction means while suppressing an increase in drive voltage.SOLUTION: A Mach-Zehnder optical waveguide has control electrodes comprising a signal electrode 3 and a ground electrode 321-323. When the ground electrode is installed over and across input and output sections, optical loss reduction means is provided on the ground electrode on at least one of the input section and the output section. The optical loss reduction means is a portion of the ground electrode that bridges over the input and output sections and is configured such that the distance to the signal electrode therefrom is similar to the distance between a portion of the ground electrode on each side of the input and output sections and the signal electrode. Width of the portion of the ground electrode bridging over the input and output sections is narrower than that of the portion of the ground electrode on each side of the input and output sections and is no less than the width of the signal electrode and no more than 75 μm. The distance between the portion of the ground electrode on one side of the input and output sections and the portion of the ground electrode on the other side is no more than 200 μm. |
