Routes towards enabling Optical Packet Networks M. Ogazi†‡, R. I. Killey‡ and A. Rafel† †BTexact Technologies, ‡University College London Abstract: All-optical-networks (AON) could one day be a reality, enabling the transport of high bit rate signals transparently and hence allowing multi-services over a single network infrastructure. The bottleneck in optical networks today is the mismatch between the current electronic processing speed and the optical line rates in WDM transmission networks. Wavelength routed networks have been shown to simplify routing and processing functions in WDM networks by providing end-to-end optical links (lightpaths), but still lack the necessary functionality for the envisioned AON. This paper assesses one of the key technologies, tunable lasers, required for optical packet transport network, and outlines the work that will be carried out to define an architecture with the functionality required to realise practical all-optical packet network. 1. Introduction It is estimated that bandwidth usage of the Internet is doubling every 6-12 months. It has also been well documented that data traffic is surpassing voice traffic, and the growing demand for network bandwidth is expected to continue in the coming years. Optical fibres employed within networks have made available huge amounts of bandwidth through the introduction of WDM technology. However, this is causing a bottleneck at the switching nodes due to the mismatch between the current electronic processing speed and the optical lines rates which are currently at 10 Gb/s and are expected to exceed 160 Gb/s in the future. Research into wavelength routed optical networks (WRON’s) has shown that such routing architectures could potentially simplify routing and processing functions in high-capacity, high bit-rate WDM networks by providing end-to-end optical channels, known as lightpaths [1]. However, wavelength routed networks lack the necessary functionality required in future flexible transport networks such as increased bandwidth granularity, the possibility of statistical multiplexing and Traffic Engineering (traffic grooming and load balancing). Optical packet- switched networks may offer these whilst delivering the advantages of optical technology such as potentially higher node capacities, less optical-electrical-optical conversions, and therefore lower network costs Such a network should still be able to provide circuit-switched services and datagram services, much like what is provided by ATM and IP networks. The essence of such a network would be to provide “packet-switching capabilities at rates that cannot be contemplated using electronic packet switching” [2]. However, the difficulties in achieving all-optical packet networks lie in the complexity of building fast enough all-optical devices suitable for packet switches, as well as processing functions to cope with the ever increasing transmission line rates and node throughputs. Some of the most important underlying technologies that would make this possible are tunable transmitters (tunable lasers), which would enable network operators to provision connections through the network dynamically when and where required, wavelength conversion which would enable flexible networks and ease control and management, and semiconductor optical amplifiers (SOA), tunable filters and space switches which are essential in reconfigurable transport networks. The aim of the UCL Adastral Park project on optical packet switching (OPS) is to study the pros and cons of different network architectures for optical packet switching in metro and