Low Loss Graded Index Polymer Optical Fiber for Local Networking

Current and future communication and computer networks require affordable, high performance interconnecting wires and cables to take advantage of ultra high-speed communication transmission lines and computational hardware. Existing singlemode optical fiber interconnects are expensive and difficult to install by local users and consumers. To address this problem, NanoSonic is developing low-cost, easily handled polymer optical fibers with bandwidth-distance products greater than 1GHz.km. Short length interconnects of such fibers would allow the transmission of 10 Gb/sec data tens of meters with negligible degradation. During Phase I, NanoSonic demonstrated the feasibility of fabricating graded index polymer optical fibers using its patented molecular-level self-assembly nanotechnology manufacturing processes. Grading the index of the fiber allows higher bandwidth-distance product, as well as dispersion shifting and dispersion flattening important to maximize the number of parallel channels in dense wavelength division multiplexed (DWDM) systems. Polymer fibers made using conventional methods do not allow the type of index modifications required to achieve such performance. Polymer optical fiber preforms were made by self-assembly, and preforms were collapsed and drawn to create prototype optical fibers. Initial measurements indicated performance close to that modeled. During Phase II, NanoSonic would work with the Polymicro subsidiary of Molex Inc., a major U.S. manufacturer of optical fiber cables and interconnects, to fabricate and evaluate improved polymer fiber prototypes. First, Phase I manufacturing equipment would be redesigned and reconstructed to incorporate proportional-integral-derivative (PID) feedback control. This would reduce errors in fiber diameter control over long lengths encountered during Phase I, allow the continuous production of kilometers of fiber that meets specifications, and maximize output per unit time while minimizing waste. Polymicro would assist with equipment design based on many years experience manufacturing specialized glass optical fiber products. Second, multiple groups, including Virginia Techs campus communication and computer network, DOE Berkeley and Oak Ridge laboratories, a regional telephone cooperative, a multi-school system data network, and two large U.S. technology companies, would perform beta site testing of short length polymer fiber interconnects. Beta test sites would potentially include GENI and ESnet hardware. Commercial Applications: The primary application of the graded index polymer fibers produced through this program would be as short length interconnects in high speed communication and computer networks - in other words, as low cost jumper cables up to a few hundred feet in length. Extended applications could include use as fibers with dispersion flattened spectral response that allows increased DWDM channel capacity; complex index grading enabled by self-assembly permits the fabrication of such waveguides.