Single-polarization fiber optics magnetic sensor
First Claim
1. In a single-polarization fiber optics magnetic sensor comprising:
- a light source;
a Faraday rotation element;
a photo-detector; and
optical waveguide means for optically coupling together said light source, Faraday rotation element and photo-detector;
the improvement wherein;
said optical waveguide means comprises polarization-maintaining optical fibers coupled to opposite sides of said Faraday rotation element without a polarizer and without an an analyzer interposed between said Faraday rotation element and said respective polarization-maintaining optical fibers, said optical fibers serving only as an optical waveguide for transmitting optical signals.
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Accused Products
Abstract
In a single-polarization fiber optics magnetic sensor comprising a light source, a Faraday rotation element, a photodetector, and optical waveguide means for optically coupling them; according to a first embodiment, the optical waveguide means comprises upstream and downstream polarization-maintaining optical fibers coupled to the entrance and exit of the Faraday rotation element without a polarizer or an analyzer interposed therebetween; according to a second embodiment, in addition thereto, the axis of polarization of the downstream polarization-maintaining optical fiber is at an angle of about 45 degrees with respect to the orientation of the linearly polarized light exiting from the Faraday rotation element at a magnetic field intensity H equal to 0; and according to a third embodiment, in addition thereto, a polarization beam splitter is located in alignment with the orientation of polarization of the exit light from the downstream polarization-maintaining optical fiber, and two polarized light beams produced by said beam splitter are received by two photo-detectors for subsequent signal computation.
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Citations
9 Claims
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1. In a single-polarization fiber optics magnetic sensor comprising:
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a light source;
a Faraday rotation element;
a photo-detector; and
optical waveguide means for optically coupling together said light source, Faraday rotation element and photo-detector;the improvement wherein; said optical waveguide means comprises polarization-maintaining optical fibers coupled to opposite sides of said Faraday rotation element without a polarizer and without an an analyzer interposed between said Faraday rotation element and said respective polarization-maintaining optical fibers, said optical fibers serving only as an optical waveguide for transmitting optical signals.
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2. In a single-polarization fiber optics magnetic sensor comprising:
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a light source;
a Faraday rotation element having an entrance and an exit;
a photo-detector; and
optical waveguide means for optically coupling together said light source, Faraday rotation element and photo-detector;the improvement wherein; said optical waveguide means comprises upstream and downstream polarization-maintaining optical fibers respectively coupled to said entrance and exit of said Faraday rotation element without a polarizer and without an analyzer interposed said Faraday rotation element and said respective polarization-maintaining optical fibers, said optical fibers serving only as an optical waveguide for transmitting optical signals; and said downstream polarization-maintaining optical fiber has an axis of polarization which is at an angle of substantially 45 degrees with respect to the orientation of linearly polarized light exiting from said Faraday rotation element at a magnetic field intensity H equal to 0. - View Dependent Claims (3, 4, 5)
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6. In a single-polarization fiber optics magnetic sensor comprising:
a light source;
a Faraday rotation element having an entrance and an exit;
a photo-detector; and
optical waveguide means for optically coupling together said light source, Faraday rotation element and photo-detector;
the improvement wherein;said optical waveguide means comprises upstream and downstream polarization-maintaining optical fibers respectively coupled to said entrance and exit of said Faraday rotation element without a polarizer and without an analyzer interposed between said Faraday rotation element and said respective polarization-maintaining optical fibers, said optical fibers serving only as an optical waveguide for transmitting optical signals; said downstream polarization-maintaining optical fiber has an axis of polarization which is at an angle of substantially 45 degrees with respect to the orientation of linearly polarized light exiting from said Faraday rotation element at a magnetic field intensity H equals to 0; a polarization beam splitter is provided and is arranged in alignment with the orientation of polarization of light exiting from said downstream polarization-maintaining optical fiber, said polarization beam splitter producing two polarized light beams; and two photo-detectors are coupled to respectively detect said two polarized light beams and to deliver resultant detection signals to a computation means. - View Dependent Claims (7, 8, 9)
Specification
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- Resources
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Current AssigneeHitachi Cable Limited (Proterial Ltd.)
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Original AssigneeHitachi Cable Limited (Proterial Ltd.)
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InventorsKajioka, Hiroshi, Iizuka, Hisao
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Primary Examiner(s)Westin, Edward P.
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Application NumberUS06/558,941Time in Patent Office867 DaysField of Search250/227, 250/231 R, 350/96.29, 350/96.30, 350/96.31, 324/96, 356/365US Class Current250/227.21CPC Class CodesG01R 33/0322 using the Faraday or Voigt ...
