Electricity: measuring and testing – Magnetic – Magnetometers
Patent
1984-08-17
1986-05-27
Strecker, Gerard R.
Electricity: measuring and testing
Magnetic
Magnetometers
324 96, 324260, 350375, 356345, G01R 33022, G01R 33023, G01B 902
Patent
active
045917868
ABSTRACT:
A fiber optic magnetic gradiometer for measuring both ac and dc magnetic field gradients. The gradiometer utilizes an optical interferometer with magnetostrictive magnetic field sensing elements in each of the interferometer arms. Ac and dc magnetic field biasing is achieved by disposing each of the magnetic field sensing elements within its own magnetic field coil and utilizing a variable dc current source for applying dc current to each magnetic coil. An ac current source at frequency w.sub.o connected across the circuits for the dc current sources is used in conjunction with a variable attenuator to control the ac bias to the respective magnetic coils. The detected output from the interferometer is processed either by bandpass filters or a spectrum analyzer to obtain the signal component at w.sub.o, which is proportional to the external dc gradient magnetic field, and at w.sub.o +w.sub.s, (where w.sub.s is external ac magnetic field frequency), which is proportional to the external ac magnetic field gradient.
REFERENCES:
patent: 4112367 (1978-09-01), Hepner et al.
patent: 4147979 (1979-04-01), Banes et al.
patent: 4264126 (1981-04-01), Sheem
patent: 4368430 (1983-01-01), Dale et al.
patent: 4376248 (1983-03-01), Giallorenzi et al.
patent: 4471219 (1984-09-01), Giallorenzi
patent: 4529876 (1985-07-01), Walker
K. P. Koo and G. H. Sigel, Jr., A Fiber-Optic Magnetic Gradiometer, Journal f Lightwave Tech., vol. LT-1, No. 3, Sep. 1983, pp. 506-513.
K. P. Koo and G. H. Sigel, Jr., Characteristics of Fiber-Optic Magnetic-Field Sensors Employing Metallic Glasses, Optic Letters, vol. 7, No. 7, Jul. 1982, pp. 334-336.
K. P. Koo, A. B. Tveten, and A. Dandridge, Passive Stabilization Scheme for Fiber Interferometers Using (3.times.3) Fiber Directional Couplers, Applied Phys. Lett. 41(7), Oct. 1, 1982, pp. 616-618.
D. A. Jackson, R. Priest, A. Dandridge, and A. B. Tveten, Elimination of Drift in a Single-Mode Optical Fiber Interferometer Using a Piezoelectrically Stretched Coiled Fiber, Applied Optics, vol. 19, Sep. 1, 1980, pp. 2926-2929.
Koo Kee P.
Sigel, Jr. George H.
Beers Robert F.
Edmonds Warren S.
Ellis William T.
Sheinbein Sol
Strecker Gerard R.
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