Advanced devices and their features for future optical networks

Nowadays, optical networks are composed of point-to-point links with electronically switching and routing functions in the network nodes (SDH-, ATM-hierarchy). The evolution of the network will go to more advanced nodes, where the signal will stay in the optical domain and will be switched, routed and processed by all-optical signal processing methods. The vision is a packet-switched optical network, where optical packets find their path through the network by self-routing through the optical nodes. For some selected functions like all-optical high-speed switching, wavelength conversion and 3R-regeneration all-optical signal processing devices are investigated in system experiments and have shown their merits. They can be modified and combined to optical circuits to perform more complex signal processing functions needed for future all optical networks. Among these functions are: 3R-regeneration, wavelength conversion, parity checking, add-drop multiplexing, signal comparison, header recognition, format conversion. We discuss the key optical signal processing devices, which are the main building blocks of the all-optical network. Further we discuss in which way we can use these basic devices at an early stage.