*** 9632281 Roark This STTR Phase I project will demonstrate a novel approach for the fabrication of highly efficient Faraday-active optical waveguide structures. Faraday-active waveguides are presently of great interest as their development is the critical enabling technology associated with the demonstration of all-fiber optical circulators. Such devices, which may be characterized as multiport nonreciprocal polarization rotators, provide a means by which the telecommunications rate may be immediately doubled on the existing optical fiber carrier infrastructure. Successful implementation will lead to full-duplex operation over "long haul" fiber carriers. The suggested circulator approach is passive, and does not therefore require external clocking controls. Separation of the signals is based only upon propagation direction; no additional losses are imposed on transmitted signals, as in the case of conventional directional couplers. The investigators propose the use of advanced thin film techniques in the development of optical fiber segments. These processes have been previously shown to promote the introduction of photonically-active dopant species at dopant levels which are orders of magnitude greater than may be produced by conventional means. The proposed technology will replace conventional bulk optics technologies, as waveguide structures with dramatically improved figures of merit will be developed characterized during the initial Phase 1 period. The Phase 1 program also includes analysis of integrated permanent magnet structures, and a design assessment for optical circulator prototype development. The development of high Verdet constant materials offers the potential for achieving optical elements which double the throughput of fiber communications links. In addition, numerous other commercial uses exist for these materials. ***
