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Semiconductor sensor for optically measuring polarization rotation of optical wavefronts using rare earth iron garnets

United States Patent

August 20, 2002
View the Complete Patent at the US Patent & Trademark Office
Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.
Duncan; Paul G. (Vienna, VA)
09/ 583,901
June 1, 2000
This invention was made with Government support under No. DE-FG02-99ER86100 awarded by the Department of Energy. The Government has certain rights in this invention.