rk based on optical SOAs. We have made no attempt to optimize the various schemes and to evaluate their performances. A large number of different schemes for the various subsystems have been proposed in lit- erature, based on optical fibers [69,70], or on other types of different nonlinear materials [71,72]. A large amount of research has also been devoted to switch architecture in order to fulfill the requirements of a modern packet switched network, and to adapt it as much as possible to the possibilities of all-optical components [73-75]. Even the network architecture and the methods to optimize the network design, if a particular version of packet switching technique and a particular switch architecture are used, have been the object of a great research effort [76,77]. Discussing the collocation of the T-OPN into a global network architecture, several ideas have been proposed, from a statistical multiplexing transport layer (like the so-called opti- cal burst network [78]) to a network layer simply integrating the physical layer with layer 2. However, up to now, all this work has had no impact on the telecommunication business, and with the passing time the fact that electronics goes ahead faster and faster decreases the probability that all-optical packet switching will become a real network technology. Nevertheless, the results of all these researches have been numerous, and they were useful in specific applications, sometimes beyond the intentions of the research group that generated them. Not only have several elements regarding the design and the possibilities of optical com- ponents and subsystems been discovered that are precious also in other applications, but digital optics, if not in telecommunication networks, is also founding several applications in the field of radars and in general microwave and millimeter wave applications [79,80]. Perhaps, if all the research on all-optical packet switching was not available, these appli- cations would have much more difficulties, or they would not be born. To