Phase-locked all-optical differential polarization demodulation

A novel scheme of differential polarization demodulation is presented and demonstrated based on a polarized asymmetrical Mach-Zehnder interferometer configuration with polarization control. To enhance the stability of the demodulator, a phase-lock device is designed, and it is composed of a symmetric 3×3 coupler and a feedback circuit. For further establishing a differential polarization-shift keying (DPolSK) transmission system, we successfully carry out the demodulation experiments on 10-Gb/s DPolSK optical signals for the first time. Due to the all-optical structure with phase-lock, our scheme is available to realize the DPolSK optical communication in practical optical fiber systems.