High Faraday Rotation Optical Waveguides for Application in Optical Circulators for Telecommunications

The fabrication of highly efficient Faraday-active optical waveguide structures is proposed. Faraday-active waveguides are presently of great interest as their development is the critical enabling technology associated with the demonstration of an all-fiber optical circulator. Such devices, which may be characterized as multiport nonreciprocal polarization rotators, provide a means by which the telecommunications rate may be immediately doubled on existing optical fiber carrier infrastructure. Successful implementation will lead to full-duplex operation over 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. We propose the use of advanced thin film techniques in the development of optical fiber segments that exhibit Faraday rotation through the introduction of high Verdet constant materials. The proposed technology will replace conventional bulk optics technologies, as waveguide structures with dramatically- improved figures of merit will be developed and characterized during the initial Phase I period. The Phase I program also includes the advancement of fiber fabrication methods and a design assessment for optical circulator prototype development.