US4342907A
Expired / Lapsed
US
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Optical sensing apparatus and method
Assignee: Individual
•
Filing: 1980-02-01
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Granted: 1982-08-03
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Expires: 2000-02-01
Abstract
Abstract A sensor for measuring stress, temperature, pressure, sound, etc. comprising an optical waveguide, preferably an optical fiber waveguide, a light source which injects light into one end of the waveguide, a deformer contacting and deforming the waveguide to cause light to couple from originally excited modes to other modes, and an optical detector to detect the change in light coupling caused by deformation of the waveguide.
Inventors
- 👤 Pedro B. Macedo
- 👤 Theodore A. Litovitz
- 👤 Nicholas Lagakos
- 👤 Robert K. Mohr
- 👤 Robert Meister
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:19
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2852; G01; G01B; G01B11/00; G01B11/16; G01B11/18; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/353; G01D5/35338; G01D5/35341; G01D5/35345; G01D5/3537; G01D5/35377; G01K; G01K1/00; G01K1/02; G01K1/024; G01L; G01L11/00; G01L11/02; G01L11/025; G02B6/10; G02B6/14; Y; Y10; Y10S; Y10S177/00; Y10S177/06
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
140 words
A sensor comprising an optical waveguide having means for transmitting light in at least two groups of modes denoted A and B, an optical light source means for injecting light into said waveguide so that light transmitted at least initially along said waveguide will be substantially in one of said groups, deformer means responsive to an external stress for deforming a region of said waveguide with such deformation being effective to change the character of the transmission of at least a portion of the light in the vicinity of the deformation from said one group to the said other group of modes, the change being approximately a linear function of the change in the external stress, and an optical detector having means to detect a change in the light in said other group only and thereby monitor said external stress.
Claim 2
Dependent Claim
140 words
A sensor comprising an optical waveguide having means for transmitting light in at least two groups of modes denoted A and B, an optical light source means for injecting light into said waveguide so that light transmitted at least initially along said waveguide will be substantially in one of said groups, deformer means responsive to an external stress for deforming a region of said waveguide with such deformation being effective to change the character of the transmission of at least a portion of the light in the vicinity of the deformation from said one group to the said other group of modes, the change being approximately a linear function of the change in the external stress, and an optical detector having means to detect a change in the light in said other group only and thereby monitor said external stress.
Claim 3
Dependent Claim
27 words
A sensor as claimed in claim 1 wherein said waveguide has two cores and modes A are in one core and modes B are in another core.
Claim 4
Dependent Claim
97 words
A sensing device as claimed in claim 1 wherein a plurality of deformer means are provided each spaced apart along spaced regions of said waveguide and wherein each said deformer means has associated therewith a connecting optical waveguide each connected to a common return optical waveguide, said optical detector's means to detect a change in the light in said other group being associated with said common return waveguide so that a time delay introduced by the spatial separation between said plurality of deformer means will serve to differentiate the external stresses experienced by each said deformer means.
Claim 5
Dependent Claim
26 words
A sensor according to claim 1 wherein said A modes are lower order bound core modes and said B modes are higher order bound core modes.
Claim 6
Dependent Claim
22 words
A sensor according to claim 1 wherein said A modes are bound core modes and said B modes are leaky core modes.
Claim 7
Dependent Claim
21 words
A sensor according to claim 1 wherein said A modes are bound core modes and said B modes are clad modes.
Claim 8
Dependent Claim
17 words
A sensor according to claim 6 wherein said bound core modes are high order bound core modes.
Claim 9
Dependent Claim
23 words
A sensor according to claim 1 wherein said A modes are bound and leaky core modes and said B modes are clad modes.
Claim 10
Dependent Claim
22 words
A sensor according to claim 1 wherein said A modes are leaky core modes and said B modes are bound core modes.
Claim 11
Dependent Claim
21 words
A sensor according to claim 1 wherein said A modes are leaky core modes and said B modes are clad modes.
Claim 12
Dependent Claim
21 words
A sensor according to claim 1 wherein said A modes are clad modes and said B modes are bound core modes.
Claim 13
Dependent Claim
21 words
A sensor according to claim 1 wherein said A modes are clad modes and said B modes are leaky core modes.
Claim 14
Dependent Claim
23 words
A sensor according to claim 1 wherein said A modes are clad modes and said B modes are leaky and bound core modes.
Claim 15
Dependent Claim
43 words
A sensor according to claim 1 further comprising means to remove light from said B modes before entering said region so that the amount of light in said B modes in said region is less than 1% of that in said A modes.
Claim 16
Dependent Claim
20 words
A sensor according to claim 1 wherein said deformer means comprise at least two objects in contact with the waveguide.
Claim 17
Dependent Claim
22 words
A sensor according to claim 15 wherein at least one of said objects has a rough surface in contact with the waveguide.
Claim 18
Dependent Claim
26 words
A sensor according to claim 15 wherein at least one of said objects has at least one ridge on its surface in contact with the waveguide.
Claim 19
Dependent Claim
23 words
A sensor according to claim 17 in which each of said objects has a set of ridges and said sets interleave each other.
Claim 20
Dependent Claim
23 words
A sensor according to claim 1 wherein said deformer means is a deformable object attached to at least two points of the waveguide.
Claim 21
Dependent Claim
42 words
A sensor according to claim 1 further comprising a pressure sensitive enclosure connected to said deformer means so that a change in pressure at the enclosure causes a change in deformation of said region of said waveguide whereby said sensor measures pressure.
Claim 22
Dependent Claim
75 words
A sensor according to claim 20 further comprising a low frequency pressure transmitting device extending through the wall of the enclosure which allows the pressure inside the enclosure to be essentially equilibrated with low frequency components of the pressure external to the enclosure so that the change in deformation of the waveguide is determined only by high frequency components of said external pressure, whereby said sensor measures the high frequency component of the external pressure.
Claim 23
Dependent Claim
26 words
A sensor according to claim 21 wherein said low frequency components are less than 1 Hertz, and said high frequency components are greater than 20 Hertz.
Claim 24
Dependent Claim
13 words
A pressure sensor according to claim 20 wherein said sensor is a hydrophone.
Claim 25
Dependent Claim
24 words
A sensor according to claim 15 in further comprising means connected to said object such that deformation of said region is proportional to acceleration.
Claim 26
Dependent Claim
46 words
A sensor according to claim 1 wherein the deformer means comprises at least two materials having dissimilar thermal expansion coefficients and configured to cause a change in deformation of said region of said waveguide upon change in temperature, whereby said sensor is used to measure temperature.
Claim 27
Dependent Claim
13 words
A sensor according to claim 1 in which the optical waveguide is predeformed.
Claim 28
Dependent Claim
19 words
A sensor according to claim 1 which further comprises means to cause said light source to be amplitude modulated.
Claim 29
Dependent Claim
15 words
A sensor according to claim 1 wherein said optical light source is a semi-conductor laser.
Claim 30
Dependent Claim
39 words
A sensor according to claim 1 wherein said A modes in said region are bound core modes, and wherein said optical means maintains the numerical aperture of the light entering said region below the numerical aperture of said region.
Claim 31
Dependent Claim
42 words
A sensor according to claim 1 wherein said A modes in said region are low order bound core modes, and wherein said optical means maintains the numerical aperture of the light entering said region substantially below the numerical aperture of said region.
Claim 32
Dependent Claim
47 words
A sensor according to claim 1 wherein said waveguide is an optical fiber waveguide, said A modes in said region are bound and leaky core modes, and said optical means includes a reduced diameter portion of said optical fiber waveguide between said light source and said region.
Claim 33
Dependent Claim
58 words
A sensor according to claim 1 wherein said A modes in said region are bound and leaky core modes, said waveguide is an optical fiber waveguide, and said optical means include means causing the numerical aperture of the light to be greater than the numerical aperture of said optical fiber waveguide, and means for removal of clad modes.
Claim 34
Dependent Claim
44 words
A sensor according to claim 14 wherein the means to remove enough light from said B modes comprises a medium surrounding the waveguide, said medium having an index of refraction greater than or equal to the index of the outer surface of said waveguide.
Claim 35
Dependent Claim
26 words
A sensor according to claim 1 wherein said light source is separated from said region by an optical fiber waveguide at least 10 meters in length.
Claim 36
Dependent Claim
26 words
A sensor according to claim 1 wherein said optical detector is separated from said region by an optical fiber waveguide at least 10 meters in length.
Claim 37
Dependent Claim
16 words
A sensor according to claim 1 wherein said optical detector is a silicon diode optical detector.
Claim 38
Dependent Claim
52 words
A sensor according to claim 1 wherein said means to detect the light in said B modes allow light to radiate from the end of the waveguide, said optical detector being positioned in such a fashion as to detect only certain angular components of the light from the end of the waveguide.
Claim 39
Dependent Claim
48 words
A sensor according to claim 1 wherein said means to detect the light in said B modes comprise optical means for imaging in a plane the light from the end of said waveguide, and means to detect light only in certain regions of the image on said plane.
Claim 40
Dependent Claim
50 words
A sensor according to claim 1 wherein said B modes are clad modes, and said optical detector comprises a medium surrounding said waveguide and having an index of refraction equal to or greater than that of the outer surface of said waveguide providing means to detect light leaving said clad.
Claim 41
Dependent Claim
33 words
A sensor according to claim 1 further comprising a section of an optical fiber waveguide for transmitting light from said B modes connected to and extending between said waveguide and said optical detector.
Claim 42
Dependent Claim
30 words
A sensor according to claim 1 comprising one said optical light source, more than one said region, more than one said deformer means, and more than one said optical detector.
Claim 43
Dependent Claim
27 words
The sensor as claimed in claim 1 wherein said waveguide is an optical fiber having a core and at least one clad material completely encircling said core.
Claim 44
Dependent Claim
26 words
A sensor according to claim 3 wherein said waveguide comprises an optical fiber waveguide extending from said light source and including each of said light regions.
Claim 45
Dependent Claim
36 words
A sensor according to claim 3 wherein at least one said region and the respective deformer means is sensitive to pressure, and at least one said region and the respective deformer means is sensitive to temperature.
Claim 46
Independent Claim
105 words
A method comprising injecting light into an optical waveguide having at least two groups of modes A and B each grojup containing at least one mode, deforming a region of the waveguide by application of an external stress, the deformation producing a change in the coupling of light between A modes and B modes, causing light entering said region to be substantially in A modes, the deformation producing a change in the light power in B modes which change is a linear function of the change in said external stress, and optically detecting said light in B modes only and thereby monitoring said external stress.
Claim 47
Independent Claim
105 words
A method comprising injecting light into an optical waveguide having at least two groups of modes A and B each grojup containing at least one mode, deforming a region of the waveguide by application of an external stress, the deformation producing a change in the coupling of light between A modes and B modes, causing light entering said region to be substantially in A modes, the deformation producing a change in the light power in B modes which change is a linear function of the change in said external stress, and optically detecting said light in B modes only and thereby monitoring said external stress.
Claim 48
Dependent Claim
41 words
A method as in claim 45 further comprising removing light from said B modes before entering said region so that the amount of light in said B modes in said region is less than 1% of that in said A modes.
Claim 49
Dependent Claim
26 words
A method as in claim 45 wherein stress is applied by compressing the waveguide between two objects at least one of which has a rough surface.
Claim 50
Dependent Claim
36 words
A method as in claim 45 further comprising enclosing said region of the wave guide with a pressure sensitive enclosure which allows the external pressure to cause the deformation of said region whereby pressure is measured.
Claim 51
Dependent Claim
31 words
A method as in claim 48 further comprising equilibrating the low frequency components of the external and internal pressure whereby only the high frequency components of the external pressure are measured.
Claim 52
Dependent Claim
13 words
A method as in claim 48 where the pressure is measured in water.
Claim 53
Dependent Claim
57 words
A method according to claim 45 wherein stress is applied to more than one said region of said waveguide for the purpose of making a plurality of measurements, passing the light from said regions to a common detector and utilizing time delay introduced by the spatial separation of said regions to monitor separately each of said regions.
Claim 54
Dependent Claim
29 words
The sensing device as claimed in claim 3 wherein each said waveguide is an optical fiber having a core and at least one clad material completely encircling said core.
Claim 55
Dependent Claim
32 words
The sensing device as claimed in claim 1 wherein said waveguide is an optical fiber having a core and said core has a plurality of clads concentrically disposed to enclose said core.
Claim 56
Dependent Claim
34 words
The sensor as claimed in claim 3 wherein each said waveguide is an optical fiber having a core surrounded by a first clad material and a second clad material surrounding said first clad material.
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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) | 1985-08-02 | 1986-02-01 | 1986-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-02 | 1990-02-01 | 1990-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-02 | 1994-02-01 | 1994-08-03 | $7700.00 | Window Closed / Lapsed |