US4994668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Planar fiber-optic interferometric acoustic sensor
Assignee: United States Department of the Navy
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Filing: 1989-09-01
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Granted: 1991-02-19
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Expires: 2009-09-01
Abstract
Abstract A sensing portion for an interferometric acousto-optic sensor and a sensor using that sensing fiber are disclosed. The sensor fiber has an outer coating of a material having a low bulk modulus. This coating greatly enhances the sensitivity of the sensor fiber. In a preferred embodiment, the material of low bulk modulus embeds the sensor fiber and any included reference fiber. Most preferably, the material having a low bulk modulus is a polymer such as polyurethane. The sensing portions made according to the present invention will usually be incorporated into sensors used for underwater exploration.
Inventors
- 👤 Nicholas Lagakos
- 👤 Joseph A. Bucaro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:12
CPC Classifications
G; G01; G01H; G01H9/00; G01H9/004
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
89 words
A sensing portion for an interferometric acousto-optic sensor portion, comprising: a concentrically wound or snaked sensor fiber having a solid light-transmitting core and a clad layer surrounding said core; and a layer of a material within which said sensor fiber is embedded, said material having a bulk modulus of no greater than about 5(10 10 ) dyn/cm 2 at 1 MHz at its ambient temperature of use, said layer being sufficiently thick to significantly increase the pressure sensitivity of said fiber within a frequency range of about 250-2500 Hz.
Claim 2
Dependent Claim
89 words
A sensing portion for an interferometric acousto-optic sensor portion, comprising: a concentrically wound or snaked sensor fiber having a solid light-transmitting core and a clad layer surrounding said core; and a layer of a material within which said sensor fiber is embedded, said material having a bulk modulus of no greater than about 5(10 10 ) dyn/cm 2 at 1 MHz at its ambient temperature of use, said layer being sufficiently thick to significantly increase the pressure sensitivity of said fiber within a frequency range of about 250-2500 Hz.
Claim 3
Dependent Claim
33 words
The sensing portion of claim 1, further comprising a buffer layer between said clad and said layer of material, and a hard plastic layer between said buffer layer and said layer of material.
Claim 4
Dependent Claim
15 words
The sensing portion of claim 1, wherein said core and clad are made of glass.
Claim 5
Dependent Claim
12 words
The sensing portion of claim 1, wherein said material is a polymer.
Claim 6
Dependent Claim
11 words
The sensing portion of claim 4, wherein said polymer is polyurethane.
Claim 7
Dependent Claim
18 words
The sensing portion of claim 1, wherein said layer of material has a thickness of about 1-20 mm.
Claim 8
Dependent Claim
119 words
An acousto-optic interferometric sensor comprising: a light source; a detector; a sensing portion including: a concentrically wound or snaked sensor fiber having a solid light-transmitting core and a clad layer surrounding said core; and a layer of a material within which said sensor fiber is embedded, said material having a bulk modulus of no greater than about 5(10 10 ) dyn/cm 2 at 1 MHz at its ambient temperature of use, said layer being sufficiently thick to significantly increase the pressure sensitivity of said fiber within a frequency range of about 250-2500 Hz; a first lead fiber extending between said light source and said sensing portion; and a second lead fiber extending between said sensing portion and said detector.
Claim 9
Dependent Claim
119 words
An acousto-optic interferometric sensor comprising: a light source; a detector; a sensing portion including: a concentrically wound or snaked sensor fiber having a solid light-transmitting core and a clad layer surrounding said core; and a layer of a material within which said sensor fiber is embedded, said material having a bulk modulus of no greater than about 5(10 10 ) dyn/cm 2 at 1 MHz at its ambient temperature of use, said layer being sufficiently thick to significantly increase the pressure sensitivity of said fiber within a frequency range of about 250-2500 Hz; a first lead fiber extending between said light source and said sensing portion; and a second lead fiber extending between said sensing portion and said detector.
Claim 10
Dependent Claim
25 words
An acousto-optic sensor according to claim 7, wherein said sensing portion further comprises a pressure-insensitive reference fiber connected to said first and second lead fibers.
Claim 11
Dependent Claim
18 words
An acousto-optic sensor according to claim 8, wherein said reference fiber is embedded within said layer of material.
Claim 12
Dependent Claim
13 words
An acousto-optic sensor according to claim 9, wherein said sensor fiber is coiled.
Claim 13
Dependent Claim
20 words
An acousto-optic sensor according to claim 10, wherein said reference fiber is coiled concentrically with respect to said sensor fiber.
Claim 14
Dependent Claim
19 words
An acousto-optic sensor according to claim 10 wherein said sensor fiber is coiled in the form of a spiral.
Claim 15
Dependent Claim
17 words
An acousto-optic fiber according to claim 10, wherein said sensor fiber is coiled into a polygonal shape.
Claim 16
Dependent Claim
17 words
An acousto-optic sensor according to claim 10, wherein said sensor fiber is coiled into an elliptical shape.
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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) | 1994-02-18 | 1994-08-20 | 1995-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-18 | 1998-08-20 | 1999-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-18 | 2002-08-20 | 2003-02-19 | $7700.00 | Window Closed / Lapsed |