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Proceedings Paper

Metallic-glass-coated optical fibers as magnetic-field sensors
Author(s): Donald C. Larson; Yu Wang Bibby; Sanjay Tyagi
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Paper Abstract

MetglasTM 2605 SC cast alloy was deposited directly onto single-mode optical fibers. Very thick amorphous films of 5 to 15 micrometers thickness were produced by triode-magnetron sputtering. The coated fibers were used as magnetic field sensing elements in one arm of a Mach-Zehnder interferometer. In the reference arm a section of fiber was wound around a piezoelectric (PZT) cylinder which was driven by a feedback correction signal to keep the sensor operating at quadrature. The sensing element was placed inside a chamber containing Helmholtz coils which produced both a dc field and an ac dither field. The magnetostructure response of the coating and the resulting phase shift in the optical fiber are dependent upon both of these fields. The phase shifts were measured as a function of the magnitudes of the dc and ac fields and the frequency of the ac field. The magnetostrictive responses had maximum values at discrete resonance frequencies. Experimental values of the magnetostriction parameter were obtained using experimental values of the phase shifts along with theoretical calculations of the magnetostrictive response. These calculations were based on a model of coherent rotation of magnetization and also an elastic model of the magnetostrictive strains for a cylindrical geometry. The maximum values of the magnetostriction parameter for the coated- fiber FOMS at resonance was estimated to be 10-5/Oe2 in comparison with non-resonant values of 5X10-5/Oe2 and 1X10-6/Oe2 for amorphous metal wire transducers and Metglas strip transducers, respectively, and 5X10-6/Oe2 for resonant Metglas cylindrical transducers.

Paper Details

Date Published: 1 August 1991
PDF: 6 pages
Proc. SPIE 1572, International Conference on Optical Fibre Sensors in China OFS(C) '91, (1 August 1991); doi: 10.1117/12.50013
Show Author Affiliations
Donald C. Larson, Drexel Univ. (United States)
Yu Wang Bibby, Wilkes Univ. (United States)
Sanjay Tyagi, Drexel Univ. (United States)

Published in SPIE Proceedings Vol. 1572:
International Conference on Optical Fibre Sensors in China OFS(C) '91
Brian Culshaw; Yanbiao Liao, Editor(s)

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