Analysis of all-optical clock recovery using a mode-locked fiber laser

We analyze and numerically simulate a model of an all-optical clock-recovery scheme in which an input data stream is used to mode-lock a fiber laser. The mode-locking is due to cross-phase modulation in a length of fiber through which the data and the laser pulses propagate simultaneously. We examine the situation when the laser pulses are close to optical solitons, so that the effect of the data stream on the laser pulses can be predicted using soliton perturbation theory. In our numerical simulations, both periodic and pseudo-random input streams are considered. The results show that for both types of data the timing jitter in the recovered clock is reduced significantly from that present in the input data. Walk-off between the two signals is included in the model and is shown to have an important role in the timing jitter reduction.