The hardware and the communication protocol of a scalable optical ring have been designed. A hardware routing has been achieved on the network interface card to minimize data packet communication latency and a simplified communication protocol has been designed to reduce communication overheads. To reduce the data packet bilking probability and have a more efficient usage of the data link layer bandwidth, a virtual multi-channel transmission mechanism has been achieved. The network supports a maximum of 16 virtual channels for each physical data link. Time slots can be dynamically assigned to each virtual channel. Zero wait time has been achieved for the switching between different virtual channels.

A broadband optical rotary joint (BORJ) was designed using Clenses. Its insertion loss was less than 2 dB at both the 1300nm and 1550nm wavelength windows. Wavelength division multiplexing (WDM) technique was adopted to increase the number of data transmission channels. Hundreds of wavelength channels can be accommodated for data transmission through relatively rotating interfaces using this BORJ. The total data transmission rate through this BORJ can be more than 200 Gbit/s. By using Dove prism, both space division multiplexing (SDM) and WDM techniques can be implemented simultaneously in the design of BORJ with C-lenses. This structure of BORJ has a low cost. It can be used for optical data transmission and optical sensing.

distributed polarization coupling in high birefringence fibres. Detailed theoretical analysis of the measurement accuracy of the testing system is presented. The main part is a Michelson interferometer with a scanning arm driven by a stepping motor. The minimum polarization coupling intensity detectable by this system is-77 dB. The maximum fibre length that can be tested under this design is more than 1 km, and the spatial resolution is better than 50mm. The influence of the opto-electro-mechanical devices on measurement accuracy has been analysed in order to improve the performance-to-cost ratio. This testing system can also be used in coherence division multiplexing optical fibre sensors.

White light interferometry has been adopted to measure distributed polarization coupling in high-birefringence waveguides. Since the coupling mode is weak compared to the exciting mode, the contrast ratio of the interferogram is very low. This will increase the difficulty of direct detection of the polarization coupling intensity. By rotating the angle between the polarization eigenmodes and the principal axis of the linear polarizer from 45

A new structure for bit synchronization in a tera-bit/s optical interconnection network has been designed using micro-electro-mechanical system (MEMS) technique. Link multiplexing has been adopted to reduce data packet communication latency. To eliminate link set-up time, adjustable optical delay lines (AODLs) have been adopted to shift the phases of the distributed optical clock signals for bit synchronization. By changing the optical path distance of the optical clock signal, the phase of the clock signal can be shifted at a very high resolution. A phase-shift resolution of 0.1 ps can be easily achieved with 30-μm alternation of theoptical path length in vacuum.