Dispersion-managed ring laser using SOA and dispersion-compensating fibre for pulse reshaping and clock recovery

Using semiconductor optical amplifier (SOA) as gain medium and active mode-locker, and a dispersion-compensating fibre (DCF) to manage cavity dispersion as well as to control and remedy pulse shape, we report an all-optical clock recovery device capable of continuously recovering the clock frequency of optical return-to-zero (RZ) signals with 10 to 12.5 GHz repetition rate. The recovered clock is chirp-free Gaussians at diffraction limit with low timing jitter of ~200 fs. We employ intra-cavity DCF in order to eliminate chirp and asymmetry of SOA-amplified pulses. This SOA+DCF ring configuration allows us to recover easily the clock over 40 nm tuning range corresponding to the SOA gain bandwidth.