Patent ID: 7409114

Claim:
An optical modulator comprising: an X-cut or Y-cut thin plate made of a material having an electrooptic effect; an optical waveguide formed in a top surface or a bottom surface of the thin plate; and a control electrode formed on the top surface of the thin plate to modulate light which propagates in the optical waveguide, wherein the thin plate has a portion having a thickness of 20 μm or less, an attenuating means which absorbs light having a specific polarization plane of a light wave which propagates in the optical waveguide is disposed in the vicinity of the optical waveguide, and the attenuating means comprises light absorbing members which are disposed at a gap which is 0.5 to 2 times the mode-field diameter of the light wave which propagates in the optical waveguide, with the optical waveguide interposed therebetween.