Characterization of All-Optical Clock Recovery for 40 Gb/s RZ-OOK and RZ-DPSK Data Using Mode-Locked Semiconductor Lasers

We investigate the characteristics of all-optical clock recovery for return-to-zero differential phase-shift keying (RZ-DPSK) and return-to-zero on-off keying (RZ-OOK) signals at 40 Gb/s using mode-locked semiconductor lasers. Two mode-locked lasers with different configurations, a bulk active layer distributed Bragg reflector laser and a quantum-dot active layer Fabry-Perot laser, are used in the experimental investigation. The results reveal the implications of the input signal power, beat spectrum linewidth of the mode-locked laser, and intensity modulation on the jitter characteristics of the recovered clock signal.