Combination of comb-like filter and SOA for preprocessing to reduce the pattern effect in the clock recovery

A comb-like filter and a semiconductor optical amplifier (SOA) were combined to preprocess the data signals before clock recovery utilizing injection mode-locked laser based on SOA. The amplitude fluctuation and timing jitters caused by the pattern effect in clock pulses were greatly reduced experimentally with this technology. Furthermore, it also demonstrated that clock could be recovered from the very degraded signals.