Patent ID: 7492975

Claim:
A broad-band optical modulator comprising: a substrate including a material of at least one of KTa x Nb 1-x O 3 (0<x<1) and K x Li 1-x Ta y Nb 1-y O 3 (0<x<1, 0<y<1); a three-dimensional optical waveguide including a material of at least one of KTa x Nb 1-x O 3 and K x Li 1-x Ta y Nb 1-y O 3 ; and a plurality of electrodes each consisting of a progressive wave electrode matching the speed of a microwave with that of a light wave, wherein the plurality of electrodes have a first electrode structure for forming an electric field in a direction parallel to TE direction of a propagating light and a second electrode structure for forming an electric field in a direction parallel to TM direction of a propagating light, the first electrode structure includes two electrodes arranged opposite each other and parallel to each other across the three-dimensional optical waveguide, and the second electrode structure includes two electrodes arranged opposite each other and parallel to each other across the three-dimensional optical waveguide, and one electrode placed on the three-dimensional optical waveguide.