Phase-locked timing extraction from 40 Gbps optical signal using harmonically mode-locked Er-doped fiber ring laser

Abstract

A prescaled 10 GHz clock recovery from a 40 Gbps time-division-multiplexed (TDM) optical signal has been demonstrated with a low-frequency-oscillator-free phase-locked loop (PLL) circuit based on four-wave-mixing in a semiconductor optical amplifier, 40 GHz optical PLL using a 10 GHz mode-locked fiber ring laser as a clock pulse was stable over 5 h within 10 KHz lock-in frequency detuning of 40 GHz TDM optical signal.