Tapered fiber optic strain gauge using cavity ring-down spectroscopy
First Claim
1. An apparatus for use with a coherent source of radiation in order to measure a strain induced into a substrate, the apparatus comprising:
- a passive fiber optic ring;
at least one sensor having a predetermined shape and in line with the fiber optic ring, the at least one sensor coupled to the substrate;
coupling means for i) introducing a portion of radiation emitted by the coherent source into the passive fiber optic ring and ii) receiving a portion of the radiation resonant in the passive fiber optic ring;
a detector for detecting a level of the radiation received by the coupling means and generating a signal responsive thereto; and
a processor coupled to the detector for determining a level of the strain inducing into the substrate based on a rate of decay of the radiation in the passive fiber optic ring.
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Accused Products
Abstract
An apparatus for measurement of strain in a material. The apparatus comprises a passive fiber optic ring; at least one sensor having a predetermined shape and in line with the fiber optic ring, the at least one sensor coupled to the substrate; coupling means for i) introducing a portion of radiation emitted by the coherent source to the passive fiber optic ring and ii) receiving a portion of the radiation resonant in the passive fiber optic ring; a detector for detecting a level of the radiation received by the coupling means and generating a signal responsive thereto; and a processor coupled to the detector for determining a level of the strain inducing into the substrate based on a rate of decay of the signal generated by the detector.
44 Citations
50 Claims
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1. An apparatus for use with a coherent source of radiation in order to measure a strain induced into a substrate, the apparatus comprising:
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a passive fiber optic ring;
at least one sensor having a predetermined shape and in line with the fiber optic ring, the at least one sensor coupled to the substrate;
coupling means for i) introducing a portion of radiation emitted by the coherent source into the passive fiber optic ring and ii) receiving a portion of the radiation resonant in the passive fiber optic ring;
a detector for detecting a level of the radiation received by the coupling means and generating a signal responsive thereto; and
a processor coupled to the detector for determining a level of the strain inducing into the substrate based on a rate of decay of the radiation in the passive fiber optic ring. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. An apparatus for measurement of strain comprising:
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a passive resonant fiber optic ring;
at least one sensor in line with the fiber optic ring, each of the at least one sensor having a tapered portion;
a coherent source emitting radiation;
a first optical coupler to provide at least a portion of the radiation emitted by the coherent source to a first section of the passive resonant fiber ring;
a second optical coupler for receiving a portion of the radiation in the passive resonant fiber ring from a second section of the resonant fiber ring; and
a processor coupled to the second optical coupler for determining a level of the strain based on a rate of decay of the radiation received by the second optical coupler. - View Dependent Claims (43, 44, 45, 46, 47)
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48. A method for measuring a strain in a material, the method comprising:
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forming a sensor from an optical fiber by tapering a portion the optical fiber;
coupling the sensor to the material such that a portion between the ends of the sensor has a predetermined amount of slack;
exposing the material to a strain;
emitting radiation from a coherent source;
coupling at least a portion of the radiation emitted from the coherent source into the fiber optic ring;
receiving a portion of the radiation traveling in the fiber optic ring; and
determining a level of strain based on a first rate of decay of the radiation within the fiber optic ring. - View Dependent Claims (49, 50)
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Specification