Patent ID: 9291838
Filing Date: 2016-03-22
CPC Classification: G02F

Claim Text:
1. An optical waveguide element comprising: a substrate having an electro-optical effect; optical waveguides formed in the substrate; a buffer layer formed on the substrate; and modulation electrodes comprising a signal electrode and a ground electrode that are formed on the buffer layer and that modulate optical waves propagating through the optical waveguides, wherein a charge diffusion layer that diffuses charges generated in the substrate is formed between the substrate and the buffer layer, the charge diffusion layer is comprised of low-refractive index material having a lower refractive index than a refractive index of the optical waveguide, a part of the charge diffusion layer is under the signal electrode and a part of the charge diffusion layer is under the ground electrode separately at least in a mutual action region in which an electric field formed by the modulation electrodes is applied to the optical waveguides, the part of the charge diffusion layer under the ground electrode is electrically connected with the ground electrode, the part of the charge diffusion layer under the signal electrode and the part of the charge diffusion layer under the ground electrode are electrically connected with each other through a member having a higher resistance value than the charge diffusion layer.