Optical Cross-Connects and Optical Packet Switches : concepts and technologies

With the data traffic boom, the backbone telecommunication networks require higher and higher capacity. Optical transmission with wavelength multiplexing division (WDM) can meet this capacity increase, up to multi-Tbit/s transmission in one single fibre. The next point for the optical networks is the implementation of a new generation of optical nodes based on wavelength routing or optical packet switching. But one must have in mind to reduce the complexity of such nodes to be cost effective. For wavelength routing, one recent approach is the multi-granularity concept which consists in routing wavelengths, bands and fibres. This approach proves to be efficient in reducing the number of switching ports of optical cross-connect architectures. Another way is to reduce the number of required wavelengths through a better sharing of the optical bandwidth. This can be done by using optical packet switching, which is studied in the frame of the IST DAVID project. The optical nodes require key technologies which are optical switches and optical filtering components. Some of these technologies have been / are studied in ACTS/IST projects (ACTS LOIS, ACTS PELICAN, IST DAVID) and French RNRT projects (RNRT CRISTO). In this talk we will present both the concepts of multi-granularity optical cross-connects and the concept of optical packet switching, illustrated with some key results of some enabling technologies involved in these systems.