Contention Resolution in Optical Packet-Switched Cross-Connects

Dit proefschrift is goedgekeurd door de promotoren: Contention resolution in optical packet-switched cross-connects / by Ronelle Geldenhuys. – Eindhoven : Technische Universiteit Eindhoven, 2007. Subject headings: photonic switching systems / optical information processing / semiconductor optical amplifiers / buffer storage. SUMMARY This thesis considers optical contention resolution in both all-optical and electro-optic implementations. After an introduction to the relevant all-optical technology developed within the COBRA research group in Chapter 2, the unique contributions of this thesis are the following: 1. In Chapter 3 various all-optical cross-connect architectures are analysed with respect to contention resolution in terms of a buffering architecture. Because an all-optical implementation is considered, this implies various necessary assumptions due to the limitations of the available technology, such as very limited signal processing, simplified header processing, and the utilisation of very simple algorithms for contention resolution. In order to obtain a realistic picture of the technology required and implementation limitations of an all-optical approach, a realistic bursty traffic model was used, the wavelength dimension was exploited in the cross-connect, and the physical amount of fibre required for the fibre delay lines was analysed. 2. The buffer requirements for the all-optical approach as outlined in Chapter 3 are compared to estimated buffer requirements based on Transmission Control Protocol (TCP) dynamics in Chapter 4. 3. A novel design for an optical threshold function based on nonlinear polarisation rotation in a single semiconductor optical amplifier (SOA) is introduced in Chapter 5. Optical threshold functions provide an all-optical way of implementing simple decisions in various applications. The method investigated in this research has the advantage of being reliant on a single active element, and being able to switch with a relatively low power optical control signal. The experimental results are supported by simulation results based on the SOA rate equations. 4. Due to the implementation challenges associated with all-optical contention resolution schemes, hybrid electro-optic solutions currently still seem to be more feasible. The second part of this thesis describes optical buffer implementations using a novel ultra-fast electro-optic switch, the CrossPoint switch. The CrossPoint switch improves on other electro-optic switches such as LiNbO 3 switches, and was used to investigate implementation challenges of a recirculating buffer, which is the buffering configuration requiring the least amount of physical fibre, and providing the most flexibility. The CrossPoint facilitates a recirculating buffer architecture with electronic control that results in a very small processing delay, and in …