Optical transparent 100Gbit/s ring-LAN employing OTDM

In order to meet the bandwidth requirements of high-end workstations and fast databases an optically transparent 100Gbit/s LAN with a ring topology employing the OTDM (Optical Time-Division Multiplexing) technique shall be designed and - in the long-term-implemented. The architecture of the LAN shall be based on the slotted ring protocol with destination release for its advantages in terms of optical transparency, bandwidth efficiency and delays. Due to the optical transparency expensive stations with high bit-rate processing can coexist with low-cost stations operating at low data rates. In particular, we intend to investigate the following topics within the proposed project: modelling of the required photonic components simulation of the complete ring-LAN at the signal transmission level design of suitable MAC-protocols for the ring-LAN and other topologies using the OTDM technique performance evaluation of the proposed MAC-protocol by means of analytical methods and extensive simulations preliminary work on the implementation of the ring-LAN in the laboratory.

The fast growth of aggregated Internet traffic and new bandwidth-intensive telecommunication applications such as supercomputer interconnections, interactive TV, multimedia as well as telemedicine applications are subject to a tremendous bandwidth demand. This demand can only be satisfied by the use of single-mode optical fibers and photonic, i.e. all-optical, networks. The OTDM technology can be used to maximize the utilization of the optical fiber by circumventing the electronic bottleneck, thereby providing high-speed access to the optical fiber. Within the scope of this project, a high bit rate packet-switched optical network based on Optical Time Division Multiplexing (OTDM) has been investigated. To the best of our knowledge, this is the first project in Austria in which an OTDM network has been researched. The studies conducted in this project concentrate primarily on an optimal node architecture, which allows further network performance improvements. The systems for fast medium access are explored in particular. New methods, like all-optical compression/decompression and new all-optical address recognition have been proposed. Furthermore, a new ultrafast all-optical demultiplexer based on an UNI- architecture (Ultrafast Nonlinear Interferometer) has been investigated. The new technologies, which are applicable in OTDM systems, have been investigated and compared in detail. Thereby, particular attention is dedicated to the new packet compression-decompression method, which was developed at the institute. This method has been examined concerning the cascadability, allowed packet length and requirements for synchronization. It allows compression of optical packets at very high bit-rates (> 100 Gbit/s) and with few limitations concerning packet size and compression rate. Several improvements in network performance were achieved and analytically demonstrated using these techniques. High speed protocols for OTDM ring networks were investigated as well. A new all-optical address recognition method which enables fast packet switching has also been analysed with simulations. Differences between incoming and local address signals, e.g. different signal powers, different pulse widths, and synchronisation mismatch have been considered particularly. The project results can be used for further theoretical and experimental research in high-speed access to the optical media.