Frame synchronization in a photonic network of time multiplexed space switches via a feedback scheme

A method for frame synchronization in a photonic network of time multiplexed space switches is presented. The method, which is based on a feedback scheme, is first introduced for frame synchronization in a single-switch configuration. The feedback scheme is then extended to both hierarchical (tree topology) and nonhierarchical (general topology) multiswitch configurations. Using this feedback scheme has the advantage of providing a mechanism for frame synchronization to be achieved initially, without the need for accurate transmission time measurements, and allowing synchronization to be maintained within very tight bounds. The methods presented require additional electronics at the switches, but electronics only for control purposes, not in the path of the information bits. However, optical delay elements are needed in the path of information bits on some links of the network. The proposed schemes also reduce the amount of synchronization equipment needed, compared to other methods