40 Gbit/s all-optical clock recovery based on the injection mode-locked fiber ring laser

Abstract

All-optical clock recovery is a key technology in all-optical 3R (Re-timing, Re-shaping, Re-amplifying) regeneration. In this paper, we demonstrate an all-optical clock recovery circuit based on injection mode-locked fiber laser. We have successfully extracted 40 GHz optical clock pulse from 40 Gb/s pseudorandom signal. Before the injected signal goes into the ring cavity, we make it pass a Mach–Zender interferometer (MZI) firstly. And thereby the clock component in the injected signal has been increased relatively, which is benefit to the clock recovery. We obtain firstly 10 GHz clock signal with perfect waveform from 10 Gb/s pseudorandom data stream, and then we extract 40 GHz clock signal from 40 Gb/s pseudorandom signal.