Patent ID: 7809218

Claim:
An optical modulator comprising: a substrate comprising an electro-optical material; a plurality of modulation electrodes on the substrate; and a plurality of optical waveguides on or in the substrate, wherein: light propagating through the plurality of optical waveguides is modulated when applying a modulation voltage on the plurality of modulation electrodes; at least a part of each of the plurality of modulation electrodes comprises a base formed on the substrate and a projection part having a width narrower than that of the base; each of the plurality of modulation electrodes comprises a pair of a signal electrode and a ground electrode; a first gap is formed between the projection part of a first signal electrode and the projection part of a first ground electrode of a first modulation electrode; a second gap is formed between the projection part of a second signal electrode and the projection part of a second ground electrode of a second modulation electrode; a third gap is formed between the first modulation electrode and the second modulation electrode; and first and second of the plurality of optical waveguides are disposed in the first gap and in the second gap, respectively, wherein the second gap is wider than the first gap.