Accession Number : ADA274120

Title :   Detection of Low-Intensity Magnetic Fields with a Magnetostrictive Fiber Optic Sensor.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Picon, Laura L.

Report Date : DEC 1993

Pagination or Media Count : 262

Abstract : This thesis presents the fabrication, evaluation, and performance results of a magnetostrictive fiber optic sensor. The sensor was fabricated using a Mach-Zehnder interferometric arrangement. Four classes of sensing arms were fabricate as: ribbons, cylinders, sandwiches, and sputter coated sheaths. The four classes of sensing arms were evaluated using MetglasTM, nickel, and a combination of MetglasTM and nickel. Optimization techniques were applied to the sensor to maximize its sensitivity. These techniques included: annealing the magnetostrictive material, operating the magnetic field at a range of frequencies, enclosing the sensor in a shielded chamber, and fabricating the sensing arms with polarization maintaining fiber optic cable. The lowest magnetic flux density that could be detected was 0.3 mG. This was achieved using a Metglas ribbon-fiber configuration with the ribbon's magnetization direction aligned perpendicularly with the applied 52 kHz AC magnetic field with a 5 volt DC bias. When operating this configuration at a 10 Hz AC magnetic field with a 5 volt DC bias, the lowest magnetic flux density that could be achieved was 8.9 mG. Fiber optic sensor, Magnetostrictive fiber optic sensor, Metglas, metallic glass, Mach-Zehnder interferometric sensor, magnetometer

Descriptors :   *FIBER OPTICS, *MAGNETIC FIELDS, *MAGNETOSTRICTION, *OPTICAL DETECTORS, ANNEALING, BIAS, CABLES, CONFIGURATIONS, DENSITY, FABRICATION, FLUX DENSITY, FREQUENCY, GLASS, MAGNETIZATION, MAGNETOMETERS, NICKEL, OPTIMIZATION, POLARIZATION, SENSITIVITY, THESES, INTERFEROMETERS.

Subject Categories : Optical Detection and Detectors
      Fiber Optics and Integrated Optics
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE