US 2003/0146748 A1Published application

Sensor for optically measuring magnetic fields

AssigneeAirak, Inc.

InventorsPaul Grems Duncan, John Alan Schroeder

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Abstract

Described are improved transmissive magneto-optical sensors that may be used to determine the magnitude and phase of a magnetic field surrounding a conductor, and when in contact with the conductor, the surface temperature of the conductor. The magneto-optical sensor may be made to be symmetric around the direction of propagation of the internal light, enabling ease of manufacturing as well as automated assembly and calibration. The magneto-optical sensor may also be made to be symmetric about the plane determined by the Faraday rotator material, thus enabling reciprocating optical paths for increased vibration and birefringence immunity. The disclosed sensors preferably include cylindrically symmetrical components, thereby making the sensor readily mass-producible.

Claims29

Dependent claims

A magneto-optic sensor comprising:

(a) a Faraday rotator material with a specified defect-free aperture area;
(b) a rotationally symmetric cylindrical carrier with an internal Faraday rotator material retaining area sized to securely hold the Faraday rotator material and an exterior circumferential marking corresponding to the plane defined by the internal Faraday rotator material retaining area;
(c) two spacers with minimum inner hole diameters corresponding to the aperture circular area of the Faraday rotator material;
(d) two polarizing films such that the film aperture exceeds the defect free aperture area of the Faraday rotator material;
(e) a rotationally symmetric retainer/adjuster assembly with a through center bore such that the bore diameter is greater than the defect free aperture area of the Faraday rotator material;
(f) two angle-polished graded-index lens assemblies having diameters larger than the Faraday rotator material defect-free aperture area;
(g) two optical fibers with a specified outer diameter;
(h) two angle-polished capillary tubes such that the angle on a single capillary tube is a complimentary angle of the said graded index angle and such that the inner bore diameter matches the specified diameter of said optical fiber;
(i) two hollow core tubes such that inner bore diameter matches the diameter of said graded index lens and said capillary tubes;
(j) two collimator outer housings such that the inner diameter of the housings matches the outer diameter of said hollow core tubes;
(k) a sensor housing with a through bore such that the inner diameter of the housing matches the outer diameter of the said collimator outer housings, and
(l) that said sensor housing with a radial alignment hole located in a position corresponding to the positional center of the sensor housing, and
(m) that said sensor housing has two sensor housing tensioning screws.

10 more elements

A magneto-optic sensor comprising:

(a) a Faraday rotator material with a specified defect-free aperture area, with a thin-film polarizer deposited on one side of said Faraday rotator material and a second thin-film polarizer deposited on the opposing side of the Faraday rotator;
(b) a rotationally symmetric cylindrical carrier with an internal Faraday rotator material retaining area sized to securely hold the Faraday rotator material and an exterior circumferential marking corresponding to the plane defined by the internal Faraday rotator material retaining area;
(c) two spacers with minimum inner hole diameters corresponding to the aperture circular area of the Faraday rotator material;
(d) two angle-polished graded-index lens assemblies such that the diameter of the assemblies is larger than the Faraday rotator material defect-free aperture area;
(e) two optical fibers with a specified outer diameter;
(f) two angle-polished capillary tubes such that the angle on a single capillary tube is a complimentary angle of the said graded index angle and such that the inner bore diameter matches the specified diameter of said optical fiber;
(g) two hollow core tubes such that inner bore diameter matches the diameter of said graded index lens and said capillary tubes;
(h) two collimator outer housings such that the inner diameter of the housings matches the outer diameter of said hollow core tubes;
(i) a sensor housing with a through bore such that the inner diameter of the housing matches the outer diameter of the said collimator outer housings, and
(j) that said sensor housing with a radial alignment hole located in a position corresponding to the positional center of the sensor housing, and
(k) that said sensor housing has two sensor housing tensioning screws.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/294,905Filed 15 Nov 2002
Priority: 15 Nov 2001
Published: 7 Aug 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01R 15/245
Using light-modulating devices: using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect
G01R 15/246
Using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect: based on the Faraday, i.e. linear magneto-optic, effect
G01R 33/0322
Using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect: using the Faraday or Voigt effect
G01R
Measuring electric variables