US4659923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber optic interferometer transducer
Assignee: Polaroid Corp
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Filing: 1983-11-09
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Granted: 1987-04-21
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Expires: 2003-11-09
Abstract
Abstract A sensor or transducer having a dual path optical fiber, such as a single mode, two polarization state, waveguide fiber, utilizes the relative change in propagation constant of the paths to sense and transduce an applied force to an interference variation and ultimately an electrical signal. In this arrangement, in-phase light is introduced to both polarized states or paths in the fiber and transmitted therealong past a stress area of birefringement inducing force and ultimately combined, thereby producing in the combined beam a variation in interference which is related to the applied force. Specific structures are provided for converting isotropic forces such as pressure and temperature to anisotropic forces on the fiber to thereby produce birefringement and to also magnify the latter effect.
Inventors
- 👤 John W. Hicks, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:13
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/344; G01L; G01L1/00; G01L1/24; G01L1/242; G01L1/243
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
141 words
A transducer comprising: an optical fiber having at least two different optical paths extending over a given length with the propagation constant of at least one of said paths being variable in response to an environmental factor applied to at least a portion of said given length; means for introducing light energy of fixed phase relationship into both said paths at one end of said length of optical fiber; means for combining the light energy transmitted along each said path so as to provide interference therebetween; evaluating means for evaluating said interference and for providing an output related thereto; and reflective means adjoining the other end of said fiber length for reflecting said light energy transmitted along both said paths back toward said one end, and said introducing means located at said one end includes means for combining the reflected energy.
Claim 2
Dependent Claim
141 words
A transducer comprising: an optical fiber having at least two different optical paths extending over a given length with the propagation constant of at least one of said paths being variable in response to an environmental factor applied to at least a portion of said given length; means for introducing light energy of fixed phase relationship into both said paths at one end of said length of optical fiber; means for combining the light energy transmitted along each said path so as to provide interference therebetween; evaluating means for evaluating said interference and for providing an output related thereto; and reflective means adjoining the other end of said fiber length for reflecting said light energy transmitted along both said paths back toward said one end, and said introducing means located at said one end includes means for combining the reflected energy.
Claim 3
Dependent Claim
39 words
The invention of claim 1 wherein said introducing means includes a polarizer for introducing light to said paths, and said polarizer operating as an analyzer for light reflected back from said other end to combine said light for interference.
Claim 4
Dependent Claim
29 words
The invention of claim 1 wherein said optical fiber is a single mode optical waveguide fiber having a single mode with two polarization states which define said different paths.
Claim 5
Dependent Claim
33 words
The invention of claim 3 wherein said combining means comprises means for polarizing the light energy transmitted along both said paths to a plane polarized state at an angle to both said paths.
Claim 6
Dependent Claim
43 words
The invention of claim 3 wherein said introducing means includes a plane polarizer illuminated with coherent radiation, with the polarization plane of said polarizer being oriented at an angle to both said paths so as to introduce light energy into each said path.
Claim 7
Dependent Claim
23 words
The invention of claim 5 wherein said polarizer is oriented to introduce approximately equal amounts of light energy into each of said paths.
Claim 8
Dependent Claim
46 words
The invention of claim 1 wherein said optical fiber comprises a tubing member having an optical fiber arrangement extending longitudinally along said tubing in a wall section thereof so as to amplify the effect on said fiber arrangement of the environmental factor applied to said member.
Claim 9
Dependent Claim
40 words
The invention of claim 7 wherein said tubing is elongated in one of its cross-sectional dimensions, so as to provide at least a pair of laterally elongated walls, and said fiber is carried within one of said laterally elongated walls.
Claim 10
Dependent Claim
46 words
The invention of claim 1 wherein said introducing means includes introducing light energy of at least two different wavelengths to both said paths, and said evaluating means includes means for separately evaluating and comparing the combined light energy of each of each of said combined wavelengths.
Claim 11
Dependent Claim
29 words
The invention of claim 9 wherein said optical fiber is a single mode optical waveguide fiber having a single mode with two polarization states which define said different paths.
Claim 12
Dependent Claim
100 words
A transducer comprising: an optical fiber arrangement including a single mode optical waveguide fiber having at least two mutually orthogonal polarization states extending over a given length with the propagation constant of at least one of said states being variable in response to an environmental factor applied to at least a portion of said given length, and a structural member adapted for amplifying the effect on said propagation constant of the environmental factor applied to said structural menber, said fiber being embedded within said structural member; means for introducing light energy of fixed phase relationship into both said polarization states.
Claim 13
Dependent Claim
100 words
A transducer comprising: an optical fiber arrangement including a single mode optical waveguide fiber having at least two mutually orthogonal polarization states extending over a given length with the propagation constant of at least one of said states being variable in response to an environmental factor applied to at least a portion of said given length, and a structural member adapted for amplifying the effect on said propagation constant of the environmental factor applied to said structural menber, said fiber being embedded within said structural member; means for introducing light energy of fixed phase relationship into both said polarization states.
Claim 14
Dependent Claim
33 words
means for combining the light energy transmitted along said fiber in said states so as to provide interference therebetween; and evaluating means for evaluating said interference and for providing an output related thereto.
Claim 15
Dependent Claim
33 words
means for combining the light energy transmitted along said fiber in said states so as to provide interference therebetween; and evaluating means for evaluating said interference and for providing an output related thereto.
Claim 16
Dependent Claim
26 words
The invention of claim 11 wherein said fiber arrangement forms a single mode waveguide fiber, and said two paths are the polarization states of said fiber.
Claim 17
Dependent Claim
26 words
The invention of claim 11 wherein said structural member is adapted to convert an isotropic stress on said member to an anisotropic stress on said fiber.
Claim 18
Dependent Claim
25 words
The invention of claim 13 wherein said fiber is a single mode waveguide fiber and said two paths are the polarization states of said fiber.
Claim 19
Dependent Claim
53 words
The invention of claim 14 wherein said fiber is embedded within one portion of said structural member having a different thermal coefficient of expansion than other portions thereof so that said structural member produces birefringing stress on said fiber arrangement due to thermal variations applied to said member thereby providing a temperature tranducer.
Claim 20
Dependent Claim
29 words
The invention of claim 15 wherein said member is an elongated rod member having an outer sleeve forming said one portion and an inner cylinder forming said other portion.
Claim 21
Dependent Claim
35 words
The invention of claim 15 wherein said member comprises an elonqated hollow tube member having a plate portion extending across its interior, said plate forming said one member and said tube forming said other member.
Claim 22
Dependent Claim
24 words
The invention of claim 11 wherein said structural member is a tubing having a fiber portion extending longitudinally therealong in a wall section thereof.
Claim 23
Dependent Claim
41 words
The invention of claim 18 wherein said tubing is elongated in one of its cross-sectional dimensions so as to provide at least a pair of laterally elongated walls, and said fiber portion is carried within one of said laterally extended walls.
Claim 24
Dependent Claim
17 words
The invention of claim 19 wherein said one wall extends across the inner diameter of said tubing.
Claim 25
Dependent Claim
23 words
The invention of claim 19 wherein said tubing is elliptical in cross-section and said one wall extends along one axis of the ellipse.
Claim 26
Dependent Claim
46 words
The invention of claim 11 wherein said structural member is a tubing elongated in one of its cross-sectional dimensions, and said fiber is carried within the opening of and extended longitudinally along said tubing in contact with opposing walls of the narrow dimension of said cross-section.
Claim 27
Dependent Claim
55 words
The invention of claim 11 wherein said fiber and said structural member include an elongated glass cylinder having a glass fiber optics core extending longitudinally therein at the surface thereof, with an overlying layer of birefringent sensitive material, and said cylinder and said layer having an index of refraction lower than that of said core.
Claim 28
Dependent Claim
21 words
The invention of claim 23 wherein the thickness of said layer is two to three times the diameter of said core.
Claim 29
Dependent Claim
20 words
The invention of claim 25 wherein said layer has an index of refraction slightly lower than that of said cylinder.
Claim 30
Dependent Claim
11 words
The invention of claim 23 wherein said layer is plastic material.
Claim 31
Dependent Claim
39 words
The invention of claim 23 wherein said structural member is coiled about a solid mandrel with the fiber bearinq portion thereof adjoining said mandrel, and further including a flexible casing surrounding said coiled member for transmitting external pressure thereto.
Claim 32
Dependent Claim
75 words
A transducer comprising: an optical fiber arrangement having at least two different optical paths extending over a given length of said fiber with the propagation constant of at least one of said paths being variable in response to force applied to at least a portion of said given length, said optical fiber arrangement being exbedded within a structural member adapted to convert an isotropic stress on said member to an anisotropic stress on said fiber.
Claim 33
Dependent Claim
75 words
A transducer comprising: an optical fiber arrangement having at least two different optical paths extending over a given length of said fiber with the propagation constant of at least one of said paths being variable in response to force applied to at least a portion of said given length, said optical fiber arrangement being exbedded within a structural member adapted to convert an isotropic stress on said member to an anisotropic stress on said fiber.
Claim 34
Dependent Claim
25 words
The invention of claim 28 wherein said fiber is a single mode waveguide fiber and said two paths are the polarization states of said fiber.
Claim 35
Dependent Claim
53 words
The invention of claim 28 wherein said fiber is imbedded within one portion of said structural member having different thermal coefficient of expansion than other portions thereof so that said structural member produces birefringent stress on said fiber arrangement due to thermal variations applied to said member thereby providing a temperature responsive transducer.
Claim 36
Dependent Claim
23 words
The invention of claim 28 wherein said structural member is a tubing having a fiber portion extending longitudinally along a wall section thereof.
Claim 37
Dependent Claim
27 words
The invention of claim 28 wherein said tubing is elongated in one of its cross-sectionoal dimensions and said fiber portion is carried within an elongated wall thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |