All-optical NRZ-DPSK clock recovery using linearly chirped fiber Bragg grating induced clock tone

All-optical clock recovery (CR) from 10 Gbps nonreturn-to-zero differential phase-shift-keying (NRZ-DPSK) signal is experimentally demonstrated, by introducing the chromatic dispersion induced clock tone into a free-running semiconductor optical amplifier (SOA) based fiber ring laser for achieving mode-locking. Since no special component is required for NRZ-DPSK demodulation, our proposed method is very promising because of its simple configuration and better stability. The good performance of our proposed configuration is fulfilled with a linearly chirped fiber Bragg grating (LCFBG) to regenerate clock tone of the NRZ-DPSK signal. The recovered clock signal with the extinction ratio of 17 dB and the root-mean-square timing jitter of 540 fs is achieved under 231−1 pseudorandom binary sequence NRZ-DPSK signals measurement. Due to the same operation principle, our configuration has the potential to implement all-optical CR for NRZ-DPSK signal with data rate up to 40 Gbps.