Optical Label Switched Networks – the FP5-IST STOLAS project

Within the STOLAS project, an EC-funded project in the 5th Framework Programme which has recently been concluded, an orthogonal optical labeling scheme using Frequency Shift Keying modulation for the 155 Mbit/s label and intensity modulation for the 10 Gbit/s payload data has been explored. This scheme enables to improve the throughput of packet-switched networks by efficient label processing, and by optical routing of the payload of the packet bursts. The label-swapping is done in intensity-driven wavelength converters, deploying cross-phase modulation in SOAs implemented in an MZI configuration. The packet bursts are switched by means of passive waveguide routers, as a function of their wavelength. The paper addresses the networking aspects of this FSK/IM orthogonal labeling scheme, and discusses the advantages and disadvantages when comparing it with alternative schemes. The key components for implementing an orthogonal label-controlled router node are addressed, as well as the node architecture, its economical aspects, and experimental results obtained. The impact of these results on the upgradability and the scalability of a network deploying orthogonal labeling are discussed, and the prospects for application in future high-capacity optical packet-switched networks. A first deployment of this labeling technique may be made in hybrid circuit-packet-switched networks, e.g. for routing of overspill packets. 1