Proposal for Optical FSK Modulator Utilizing Polarization-Reversed Structure

We propose a novel optical frequency-shift-keying (FSK) modulator with polarization-reversed structure. Using the three-branch waveguide interferometer, one optical side-band generated by RF modulation signal is enhanced but the optical carrier and the other optical side-band are suppressed at the same time. The enhanced optical side-band can be switched by the binary data-signal, therefore the optical FSK signal is generated.