White light interferometry has been adopted to measure the distributed polarization coupling in high bireffingence thers A supoduminescent diode is adopted as the optical source in the white light interierometer To enlarge the reasorement range, the light beam in the scanning arm of the Micbelson interferometer is reflected three limes. Thus descanning range of the interferometer is doubled The full-width half-maximum spectrum of the SLD is 50nm, and cesenal wavelength is 1300mm. If the modal birefdngence of the I-IBF is 5

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

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 0.1ps can be easily achieved with 30-μm alternation of the optical path length in vacuum.

A mugichannel ring is designed. Each sublayer network is connected to the dng with an access node (AN), which can transmit data at every wavelength with a tunable laser diode. The data transmission speed at each wavmength is 1.25Gbit/s. With eight wavelengths, a total bandwidth of 10Gbg/s can be obtained With a bandpass filter, the de-sired optical signal can be dropped down at the access node On receiving a data packet, the optical signal is split into two parts. One part is converted to an electrical signal and its destination address is extracted and vedtied. If the data packet belongs to the local subnatwork, it is received. Otherwise. it is retransmitted to the next access node with a selected wavelength. So pipelining data transmlssien can be achieved among different wavelengths. And this natwodt is a multipipeline structure. The data processing time is less than 30Ons, and all of the processing procedure is implemented via a fieid programmable gate array (FPGA). So the communication latency and communication overheads can be decreased. Meanwhile, the ring topology has good sca/ability. More wavelengths can he adopted for a large-scale network with more access nodes.

The hardware and the communimtion protocol of a statable optical ring have been designed. A hoxdware routing has been achieved on the network interface card to minimize data paeket communieation 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 umgn of the data link layer bandwidth, a virtuaI multi channel transmimion mechanism has been achieved. The network supports a maximum of 16 virtual channds 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.