Patent ID: 7911675

Claim:
An optical modulation device comprising: an optical splitter for splitting input light into a first input beam and a second input beam; an optical intensity modulator for modulating intensity of the first input beam in response to a modulating signal; a variable optical phase shifter for shifting phase of the second input beam, wherein, said variable optical phase shifter has a waveguide and includes one of a semiconductor laser and a semiconductor optical amplifier, the second input beam travels through said waveguide, and said waveguide has a refractive index that varies with current injected into said variable optical phase shifter; and an optical combiner for combining an output beam of said optical intensity modulator and an output beam of said variable optical phase shifter into a combined beam and outputting the combined beam, wherein the phase shift produced by said variable optical phase shifter is controlled by the current that is externally injected into said variable optical phase shifter of said optical modulation device.