Synchronization technique for optical OOK receivers

The authors present a purely digital timing recovery scheme for optical OOK receivers, which offers the advantages of low hardware complexity and low jitter. In this technique, the computation of the timing function is based on symbol-rate samples of the received signal. A gain scheduling strategy is used for the timing updates; a short training set of symbols accompanied by large gain for the timing updates is followed by data symbols and low gain for the timing updates. This allows the use of large correction step sizes during training, leading to fast convergence. It is particularly suitable for an all digital optical system