A novel structure has been designed for bit synchronization in a terabit-per-second optical interconnection network with adjustable optical delay lines, The two-stage network consists of 1024 optical links connected to a central switching module. A distributed optical clock network is designed for bit synchronization at each node computer. Zero link setup time can be achieved by precisely atching the phases of each pair of clock and signal. The link-to-link switching time can be reduced to less than 20 ns in the two-stage network. Even in a three-stage network that can accommodate 32,768 optical links, the link switching time can be maintained below 30 ns. At the same time, a tetal bidirectional band width of 98.304 Tbit/s can be obtained. Since bit synchronization is achieved entirely in the optical domain, this structure is independent of link transmission rates.

Piezo-electronic transducer is used in combination with mechanical scanning devices to improve measurement accuracy in a distributed polarization coupling detection system. For mechanical scanning range of 150mm with 200-nm resolution, the measurement error of polarization-coupling intensity can be improved from 38% to 2% in combination with a 20-nm resolution piezo-electronic transducer.

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.

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.