Patent ID: 7035488
Filing Date: 2006-04-25
Classification: G02F

Abstract:
1. An optical waveguide element comprising a substrate made of a material with electro-optical effect, a Mach-Zehnder type optical waveguide formed at the main surface of the substrate, and a modulating electrode to control an optical wave through the Mach-Zehnder type optical waveguide, the Mach-Zehnder type optical waveguide including a first branched optical waveguide and a second branched optical waveguide, the modulating electrode including a signal electrode to modulate an optical wave through the first branched optical waveguide of the Mach-Zehnder type optical waveguide and a ground electrode serving as an opposed electrode for the signal electrode, the ground electrode being composed of a first ground electrode and a second ground electrode which are opposed each other with sandwiching the signal electrode, the first branched optical waveguide being disposed under the signal electrode or in between the first ground electrode and the signal electrode, the second branched optical electrode being disposed under the second ground electrode, the second ground electrode being partially cut away along the long direction and divided into three parts, the divided first part being disposed on the almost center line between the first and the second branched optical waveguides, the divided second part and the divided third part being almost the same as the signal electrode and the first ground electrode in figuration and dimension, respectively, to substantially symmetrize the modulating electrode composed of the signal electrode, the first and the second ground electrodes on the center line between the first and the second branched optical waveguides, the width W