A broadband optical rotary joint (BORJ) was designed using Clenses. Its insertion loss was less than 2dB 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 200Gbit/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.

A novel structure has been designed for bit synchronization in a terabit-per-second optical interconnection network with adjustable op tical delay lines, The two-stage network consists of 1024 optical links connected to a central switching module. A distributed optical clock net-work is designed for bit synchronization at each node computer. Zero link setup time can be achieved by precisely matching 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 30ns. At the same time, a total bidirectional band-width of 98304Tbit/s can be obtained. Since bit synchronization is achieved entirely in the optical domain, this structure is independent of link transmission rates.

The insertion loss of a fiber optcalirotary joiot depends on the mechenical misalgnments of the collimating lenses To achieve 3-dB or less Insertion loss, the lateral nusanment of the graded index (GRIN) lenses should be less than 100μm, and the angular tilt at these lenses is limoted to 0.1 deg These requirements cauee a high mechanical fabrication and assemciy cost. To solve this problem, we design a single-channel optica1 rotary joint using a bulk optical detector The requirement on lateral misalignment is relaxed to 500μm, and the angular tilting is relaxed to 2 deg. Using this method, the cost of Ihe oplical rotary joint can be dramatically reduced

In this paper, a new scheme has been proposed to achieve high-performance local area network adoptii/g 5～15nm separdted eosrse wavelength division multiplexing (CWDM) technique. Using this scheme, the current single-wavelength gigabit Ethernet can be sesmlessly upgrdded to multi-wavelength network. Not only can the network bandwidth be broadeneds but also wavelength routing can be achieved among different sub-networks. The dam packet communication latency can be reduced one-to-two magnitudes in comparison with that of the current gigabit Ethernet. To expand the network scale, multi-wavelength-window CWDM teehifique can be adopted. Two kinds of network interface cards have been designed using opto-electronics devieosst the 850nm and 1300nm wavelength windows, respectively. Experiment.s indicate that the two kinds of CWDM signals can be selectively received at the corresponding optical detectors. By introducing two optical droppiing devices in the network, multi-wavelength-window (850nm, 1300nm and 1550nm) CWDM system can be achieved.

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 contrastratio 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˚ to 85˚, the contrast ratio of the interferogram can be improved more than 10 times. As a result, the measurement sensitivity can be improved more than 100 times.