Patent ID: 7660030

Claim:
A reciprocating optical modulation system comprising: an optical modulator modulating an output light by controlling one of an intensity, a phase and a frequency of an input light; a first fiber grating transmitting a light of a first predetermined frequency domain, the light being outputted from the optical modulator and being inputted into the first fiber grating, the first fiber grating being configured to reflect lights of other frequencies than the first predetermined frequency domain; a second fiber grating transmitting a light of a second predetermined frequency domain, the light being outputted from the optical modulator and being inputted into the second fiber grating, the second fiber grating being configured to reflect lights of other frequencies than the second predetermined frequency domain; and a signal source generating a modulating signal to be inputted to the optical modulator, wherein both of the first fiber grating and the second fiber grating are chirp gratings, the gratings of the two chirp gratings being configured to be symmetrical with respect to the optical modulator.