Patent ID: 7340114

Claim:
An optical modulator comprising: a substrate having an electro-optical effect; a plurality of Mach-Zehnder type optical waveguides formed in series on said substrate; a plurality of electrodes provided independently of each other and individually for said plurality of Mach-Zehnder type optical waveguides, wherein said plurality of electrodes includes a respective electrode supplying a clock signal to one of said plurality of Mach-Zehnder type optical waveguides, and a different respective electrode supplying a data signal to a different one of said plurality of Mach-Zehnder type optical waveguides; and a plurality of light detectors corresponding, respectively, to said plurality of Mach-Zehnder type optical waveguides, for detecting the intensity of light emitted from said plurality of Mach-Zehnder type optical waveguides, respectively, wherein each light detector detects the intensity of the light emitted from the corresponding Mach-Zehnder type optical waveguide without the detected light having been passed through a Mach-Zehnder type optical waveguide positioned downstream of said corresponding Mach-Zehnder type optical waveguide in the series.