Patent ID: 7869668

Claim:
A method for generating a carrier residual signal, comprising the steps of: causing a light wave having a specific wavelength to enter into an optical modulating unit comprising an SSB optical modulator formed on a substrate and a bypass optical waveguide that is me same substrate and that connects an input part of the SSB optical modulator to an output part of the SSB optical modulator; providing carrier component related to a zero-order Bessel function in the bypass optical waveguide; providing a specific signal component related to a specific high-order Bessel function while suppressing signal components other than the specific signal component related to the specific high-order Bessel function in the SSB optical modulator: causing to be included in a light wave emitted from the optical modulating unit the carrier component and the specific signal component; and setting a ratio of optical intensity between the carrier component and the specific signal component substantially to 1.