| 主权项 |
1. An optical control device comprising:
a substrate having an electro-optical effect; an optical waveguide formed in the substrate; and a modulation electrode modulating optical waves propagating in the optical waveguide, wherein the optical waveguide is a nested type optical waveguide in which a first sub Mach-Zehnder type optical waveguide and a second sub Mach-Zehnder type optical waveguide are inserted into a main Mach-Zehnder type optical waveguide in an embedded form, the modulation electrode comprises ground electrodes and at least two separate signal electrodes, at least a first one of the separate signal electrodes is arranged to modulate optical waves propagating in the first sub Mach-Zehnder type optical waveguide, the ground electrodes include a first ground electrode and a second ground electrode with the first sub Mach-Zehnder type optical waveguide interposed therebetween, the second ground electrode is arranged to be interposed between the first sub Mach-Zehnder type optical waveguide and the second sub Mach-Zehnder type optical waveguide, a first electrical connection member electrically connects the first ground electrode to the second ground electrode, and the first electrical connection member is disposed to cross over the first sub Mach-Zehnder type optical waveguide and said first separate signal electrode that modulates optical waves propagating in the first sub Mach-Zehnder type optical waveguide, at least a second one of the separate signal electrodes is arranged to modulate optical waves propagating in the second sub Mach-Zehnder type optical waveguide, the ground electrodes further comprise a third ground electrode, and the second sub Mach-Zehnder type optical waveguide is interposed between the second ground electrode and the third ground electrode, a second electrical connection member electrically connects the second ground electrode to the third ground electrode, and the second electrical connection member is disposed to cross over the second sub Mach-Zehnder type optical waveguide and said second separate signal electrode that modulates optical waves propagating in the second sub Mach-Zehnder type optical waveguide, at least one of the first electrical connection member and the second electrical connection member is comprised of a plurality of conductive members formed of conductive wire or conductive ribbon, and a gap between the conductive members is set to a half wavelength or less of a modulating electrical signal propagating in the signal electrode over which the conductive members cross. |
