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

Abstract

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.

Inventors:

Duncan, Paul G ^[1]

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1. 8544 Electric Ave., Vienna, VA 22182

Issue Date:

2002-01-01

Research Org.:

Airak, Inc. (US)

OSTI Identifier:

874673

Patent Number(s):

6437885

Assignee:

Duncan; Paul G. (8544 Electric Ave., Vienna, VA 22182)

Patent Classifications (CPCs):

G - PHYSICS G01 - MEASURING G01R - MEASURING ELECTRIC VARIABLES

G - PHYSICS G02 - OPTICS G02B - OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS

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G - PHYSICS G01 - MEASURING G01R - MEASURING ELECTRIC VARIABLES

G01R15/245 - {using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect}
G01R15/246 - {based on the Faraday, i.e. linear magneto-optic, effect}
G01R33/0322 - {using the Faraday or Voigt effect}

G - PHYSICS G02 - OPTICS G02B - OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS

G02B6/42 - Coupling light guides with opto-electronic elements
G02B6/4207 - {with optical elements reducing the sensitivity to optical feedback
G02B6/4214 - {the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device
G02B6/4216 - {incorporating polarisation-maintaining fibres

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DOE Contract Number:  

FG02-99ER86100

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

semiconductor; sensor; optically; measuring; polarization; rotation; optical; wavefronts; rare; earth; iron; garnets; described; design; garnet; element; methods; interrogating; coupling; waveguide; electrical; processing; monitoring; linearly; polarized; wavefront; undergoing; external; modulation; due; magnetic; field; current; fluctuation; faraday; effect; intrinsic; property; rare-earth; materials; rotate; light; presence; coated; thin-film; mirror; effectively; double; path; length; providing; twice; sensitivity; strength; temperature; change; magnetic field; rare earth; electrical current; optical path; optical sensor; sensor element; optical method; optical wave; /359/324/