US4329058A
Expired / Lapsed
US
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Method and apparatus for a Fabry-Perot multiple beam fringe sensor
Assignee: Boeing North American Inc
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Filing: 1979-01-22
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Granted: 1982-05-11
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Expires: 1999-01-22
Abstract
Abstract A method and the resulting apparatus for implementing a unique multiple beam fringe sensor that is adapted to be interfaced with a low cost, compact fiber optic transmission system in order to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a Fabry-Perot gap formed between the ends of two mated optical fibers. By examining the optical characteristics of light that is transmitted through the Fabry-Perot sensor gap, an indication of gap width can be ascertained. Accordingly, a change in Fabry-Perot sensor gap width is related to a change in the particular physical parameter to be measured.
Inventors
- 👤 Kenneth A. James
- 👤 William H. Quick
- 👤 Virgil H. Strahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:07
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/284; G01; G01D; G01D5/00; G01D5/26; G01D5/266; G01D5/268; G01K; G01K11/00; G01K11/12; G02B6/00; G02B6/24; G02B6/26; G02B6/262; G02B6/28; G02B6/293; G02B6/29346; G02B6/29358; G02B6/29359
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
153 words
A method for making an apparatus for optically sensing a physical parameter, said method comprising the steps of: forming optically flat surfaces on one end of each of a pair of optical fibers, forming a raised contact means on the flat end surface of a first of said pair of optical fibers, applying a first spacer means around said raised contact means, shortening said raised contact means, so that said contact means is recessed with respect to said first spacer means, mating said first spacer means of said first optical fiber to the flat end surface of the second of said pair of optical fibers, so that a Fabry-Perot gap is formed between said recessed contact means and the flat end surface of said second optical fiber, and transmitting light through said Fabry-Perot gap and examining the optical characteristics of said light for providing an indication of the physical parameter to be sensed.
Claim 2
Independent Claim
153 words
A method for making an apparatus for optically sensing a physical parameter, said method comprising the steps of: forming optically flat surfaces on one end of each of a pair of optical fibers, forming a raised contact means on the flat end surface of a first of said pair of optical fibers, applying a first spacer means around said raised contact means, shortening said raised contact means, so that said contact means is recessed with respect to said first spacer means, mating said first spacer means of said first optical fiber to the flat end surface of the second of said pair of optical fibers, so that a Fabry-Perot gap is formed between said recessed contact means and the flat end surface of said second optical fiber, and transmitting light through said Fabry-Perot gap and examining the optical characteristics of said light for providing an indication of the physical parameter to be sensed.
Claim 3
Dependent Claim
33 words
The method recited in claim 1, including the additional step of shortening said raised contact means at a lower temperature than any of those to which said sensing apparatus is to be exposed.
Claim 4
Dependent Claim
35 words
The method recited in claim 1, including the additional step of forming said raised contact means from a material having a temperature coefficient of expansion that is different from that of said first spacer means.
Claim 5
Dependent Claim
32 words
The method recited in claim 1 including the additional step of vapor depositing said first spacer means onto the end surface of said first optical fiber and around said raised contact means.
Claim 6
Dependent Claim
28 words
The method recited in claim 1, including the additional step of forming said optically flat surfaces by hemispherically terminating the first ends of said pair of optical fibers.
Claim 7
Dependent Claim
82 words
The method recited in claim 1, including the additional steps of applying a second spacer means around the outer periphery of the flat end surface of said second optical fiber, so that a central depression is formed within said second spacer means, and mating the first spacer means of said first optical fiber to the second spacer means of said second optical fiber and aligning said contact means with the depression of said second spacer means to form the Fabry-Perot gap therebetween.
Claim 8
Dependent Claim
30 words
The method recited in claim 6, including the additional step of vapor depositing said second spacer means around the periphery of the flat end surface of said second optical fiber.
Claim 9
Dependent Claim
153 words
A Fabry-Perot optical sensor for sensing a physical parameter, said sensor comprising: first and second optical fibers, each of said optical fibers having a first optically flat end thereof, source means to provide one of said optical fibers with a supply of light, raised contact means connected to the first end of said first optical fiber, and spacer means positioned on the first end of said first optical fiber and around said raised contact means, said spacer means being particularly dimensioned so that said contact means is recessed with respect thereto, said spacer means adapted to be mated to the first end of said second optical fiber to form a Fabry-Perot gap between said raised contact means and the first end of said second optical fiber, the optical characteristics of light being transmitted from said source means through said Fabry-Perot gap via said optical fibers being indicative of the parameter to be sensed.
Claim 10
Dependent Claim
153 words
A Fabry-Perot optical sensor for sensing a physical parameter, said sensor comprising: first and second optical fibers, each of said optical fibers having a first optically flat end thereof, source means to provide one of said optical fibers with a supply of light, raised contact means connected to the first end of said first optical fiber, and spacer means positioned on the first end of said first optical fiber and around said raised contact means, said spacer means being particularly dimensioned so that said contact means is recessed with respect thereto, said spacer means adapted to be mated to the first end of said second optical fiber to form a Fabry-Perot gap between said raised contact means and the first end of said second optical fiber, the optical characteristics of light being transmitted from said source means through said Fabry-Perot gap via said optical fibers being indicative of the parameter to be sensed.
Claim 11
Dependent Claim
28 words
The Fabry-Perot optical sensor recited in claim 8, wherein said raised contact means and said spacer means are formed from respective materials having different temperature coefficients of expansion.
Claim 12
Dependent Claim
41 words
The Fabry-Perot optical sensor recited in claim 8, wherein said raised contact means has a cylndrical configuration, the respective ends of said contact means and said second optical fiber that form said Fabry-Perot gap being in parallel alignment with one another.
Claim 13
Dependent Claim
37 words
The Fabry-Perot optical sensor recited in claim 8, wherein said source means comprises a source of white light interfaced with the second end of said first optical fiber in order to supply light to said Fabry-Perot gap.
Claim 14
Dependent Claim
54 words
The Fabry-Perot optical sensor recited in claim 8, further including photo-electric detection means interfaced with the second end of said second optical fiber and responsive to the optical signals that are transmitted thereto from said Fabry-Perot gap via said second optical fiber, so that an electrical equivalent of said physical parameter can be provided.
Claim 15
Dependent Claim
41 words
The Fabry-Perot optical sensor recited in claim 12, further including decoder means, said decoder means adapted to receive the electrical equivalent of the physical parameter from said photo-electric detector in order that a digital representation of said parameter can be provided.
Claim 16
Dependent Claim
142 words
An optical transducer for sensing a physical parameter, said transducer comprising: light source means, first and second light transmitting means, Fabry-Perot gap means formed between first ends of said first and second light transmitting means, each of said first ends having a partially reflective surface, said Fabry-Perot gap means receiving incident light signals from said source means via said first light transmitting means and supplying output light signals to said second light transmitting means, said Fabry-Perot gap means having a dimension that is sensitive to a parameter change, the spectral characteristics of the output light signals being transmitted through said Fabry-Perot gap means providing an indication of the dimension of said gap means and, accordingly, the physical parameter to be sensed, and means for detecting the spectral characteristics of said output light signals so as to provide the indication of said parameter.
Claim 17
Dependent Claim
142 words
An optical transducer for sensing a physical parameter, said transducer comprising: light source means, first and second light transmitting means, Fabry-Perot gap means formed between first ends of said first and second light transmitting means, each of said first ends having a partially reflective surface, said Fabry-Perot gap means receiving incident light signals from said source means via said first light transmitting means and supplying output light signals to said second light transmitting means, said Fabry-Perot gap means having a dimension that is sensitive to a parameter change, the spectral characteristics of the output light signals being transmitted through said Fabry-Perot gap means providing an indication of the dimension of said gap means and, accordingly, the physical parameter to be sensed, and means for detecting the spectral characteristics of said output light signals so as to provide the indication of said parameter.
Claim 18
Dependent Claim
180 words
An optical transducer for sensing a physical parameter, said transducer comprising: light source means, first and second light transmitting means, Fabry-Perot gap means formed between first ends of said first and second light transmitting means, said Fabry-Perot gap means receiving incident light signals from said source means via said first light transmitting means and supplying output light signals to said second light transmitting means, said Fabry-Perot gap means having a dimension that is sensitive to a parameter change, the optical characteristics of the light signals being transmitted through said Fabry-Perot gap means providing an indication of the dimension of said gap means and, accordingly, the physical parameter to be sensed, and spacer means positioned between the first ends of said first and second light transmitting means to form said Fabry-Perot gap means, said spacer means being fabricated from a material that is responsive to a parameter change for causing corresponding changes in the dimensions of said spacer means and said Fabry-Perot gap means, so as to alter the optical characteristics of the light signals being transmitted through said gap means.
Claim 19
Dependent Claim
180 words
An optical transducer for sensing a physical parameter, said transducer comprising: light source means, first and second light transmitting means, Fabry-Perot gap means formed between first ends of said first and second light transmitting means, said Fabry-Perot gap means receiving incident light signals from said source means via said first light transmitting means and supplying output light signals to said second light transmitting means, said Fabry-Perot gap means having a dimension that is sensitive to a parameter change, the optical characteristics of the light signals being transmitted through said Fabry-Perot gap means providing an indication of the dimension of said gap means and, accordingly, the physical parameter to be sensed, and spacer means positioned between the first ends of said first and second light transmitting means to form said Fabry-Perot gap means, said spacer means being fabricated from a material that is responsive to a parameter change for causing corresponding changes in the dimensions of said spacer means and said Fabry-Perot gap means, so as to alter the optical characteristics of the light signals being transmitted through said gap means.
Claim 20
Dependent Claim
39 words
The optical transducer recited in claim 15, wherein each of said first and second light transmitting means is an optical fiber, said optical fibers and said spacer means being fabricated from respective materials having different temperature coefficients of expansion.
Claim 21
Dependent Claim
27 words
The optical transducer recited in claim 15, wherein the first ends of said first and second light transmitting means are in substantially parallel alignment with one another.
References Cited (Backward Citations)
US4171915A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-10 | 1985-11-09 | 1986-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-10 | 1989-11-09 | 1990-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-10 | 1993-11-09 | 1994-05-11 | $7700.00 | Window Closed / Lapsed |