Patent ID: 7245788

Claim:
An optical modulator comprising: a substrate with an electro-optic effect, an optical waveguide section formed on the substrate, and a modulation electrode for modulating light passing through the optical waveguide section, wherein the optical waveguide section is a double nested Mach-Zehnder type optical waveguide where two sub Mach-Zehnder type optical waveguides are incorporated into branch waveguides of a main Mach-Zehnder type optical waveguide, the modulation electrode comprises a plurality of modulation electrodes for modulating lights passing through the two sub Mach-Zehnder type optical waveguides, a branch element for branching a modulation signal into a plurality of modulation signals having identical waveforms is formed, a delay line for generating a specific phase difference between the plurality of modulation signals is interposed between a plurality of signal lines for applying the plurality of modulation signals branched by the branch element into the plurality of modulation electrodes, and the plurality of modulation signals having the identical waveforms and the specific phase difference are applied into the lights passing through the two sub Mach-Zehnder type optical waveguides.