Ultrahigh-speed clock recovery with optical phase lock loop based on four-wave-mixing in a semiconductor optical amplifier

A new phase lock loop (PLL) is proposed and demonstrated for clock recovery from 40 Gbps time-division-multiplexed (TDM) optical signal using simple o ptical phase lock loop circuit. The proposed clock recovery scheme improves the jitter effect in PLL circuit from the clock pulse laser of harmonicall y-mode locked fiber laser. The cross-correlation component between the opti cal signal and an optical clock pulse train is detected as a four-wave-mixi ng (FWM) signal generated in SOA. The lock-in frequency range of the clock recovery is found to be within 10 KHz. (C) 2000 Elsevier Science B.V. All r ights reserved.