All-optical packet synchronizer for slotted core/metropolitan networks

In the framework of synchronous optical packet networks, a cost-effective all-optical synchronizer is an important building block to effectively switch the packets through an optical router. In striking difference to its time-division multiplexing-based electronic counterparts requiring bit level synchronization, an optical router can operate effectively with a much coarser synchronization at packet level. Such a synchronizer is proposed, which can compensate for the time variations between packets transported over several wavelengths. The requested synchronization is achieved with a resolution that is a fraction of the packet duration, which is a process that is adequate to compensate for the delays due to thermal variations between the transport fibers. Because this WDM synchronizer is constructed using slowly reconfigurable and mainly passive components, it is potentially a cost-effective solution. The principle of operation of this synchronizer is described in the context of synchronous slotted optical networks; the functionality of the various building blocks is analyzed, and practical implementation issues of various subsystems for a 80 Gbit/s synchronizer are discussed. Finally, an experimental validation of the proposed synchronizer is made demonstrating the viability of the method.