Apparatus for measuring electrical or magnetic fields by absorption spectrum change
AssigneeASEA Aktiebolag
InventorsTorgny Brogardh, Olof Engstrom
Life of this patent
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Abstract
A fiber optical measuring device for measuring a magnetic or electric field comprises an optical modulator influenced by the field. The optical properties of the modulator are dependent on the magnetic or electric field acting on the modulator. The optical property which is made use of is the field dependence of at least one absorption edge of the radiation absorption spectrum of the modulator material. Optical fibers may be used for feeding light into the modulator and for leading away light that has passed through the modulator.
Claims25
An optical measuring device for measuring magnetic fields, comprising:
- at least one radiation modulator consisting of a material having spectral properties dependent on said field;
- means for measuring said spectral properties by radiation in a given wavelength range passing through said modulator, said modulator, in said given wavelength range, having at least one absorption edge in the absorption sprectrum of said material being modified by application of said field, said field dependence being caused by changes in the Landau levels in a magnetic field;
- at least one optical fiber for conducting light to and from the modulator;
- and
- said material having a specific resistivity at least as great as that of a semiconductor material.
An optical measuring device for measuring electrical fields, comprising:
- at least one radiation modulator consisting of a material having spectral properties dependent on said field;
- means for measuring said spectral properties by radiation in a given wavelength range passing through said modulator, said modulator, in said given wavelength range, having at least one absorption edge in the absorption spectrum of said material being modified by application of said field, said field dependence being caused by changes in the Franz-Keldysh effect of an electric field;
- at least one optical fiber for conducting light to and from the modulator;
- and
- said material having a specific resistivity at least as great as that of a semiconductor material.
Dependencies are inferred from the claim text.