CA2069579A1 - Transducers - Google Patents
TransducersInfo
- Publication number
- CA2069579A1 CA2069579A1 CA 2069579 CA2069579A CA2069579A1 CA 2069579 A1 CA2069579 A1 CA 2069579A1 CA 2069579 CA2069579 CA 2069579 CA 2069579 A CA2069579 A CA 2069579A CA 2069579 A1 CA2069579 A1 CA 2069579A1
- Authority
- CA
- Canada
- Prior art keywords
- coils
- transducer
- optical
- fibre
- optical fibre
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000013307 optical fiber Substances 0.000 claims abstract description 13
- 239000011343 solid material Substances 0.000 claims description 2
- 239000000835 fiber Substances 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 7
- 229920002635 polyurethane Polymers 0.000 abstract 1
- 239000004814 polyurethane Substances 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 description 13
- 239000003822 epoxy resin Substances 0.000 description 4
- 229920000647 polyepoxide Polymers 0.000 description 4
- 238000004804 winding Methods 0.000 description 3
- 238000003491 array Methods 0.000 description 1
- 239000013536 elastomeric material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
ABSTRACT
A large area hydrophone is described using optical fibre as the sensing medium, consisting of four small coils of fibre joined together serially, each coil wound on a mandrel and the whole assembly encapsulated in an appropriate material such a polyurethane.
Figure 3
A large area hydrophone is described using optical fibre as the sensing medium, consisting of four small coils of fibre joined together serially, each coil wound on a mandrel and the whole assembly encapsulated in an appropriate material such a polyurethane.
Figure 3
Description
P/8699~P48/CA
2~6~7~
-- 1 .
Improvements Relatin~ to Transducers This invention relates to transducers (e.g.
hydrophones) and relates more specifically to transducers comprising optical fibres forming part of an array.
Arrays o~ large area hydrophones require large numbers o~ individual transducers.
Large area hydrophones are currently in use or proposed for sonar systems which need large filled apertures and which required good rejection at high acoustic wavenumbers in order to reject flow noise~
Optical flbre transducers for use in hydrophones are known, for example in~our co-pending patent application No.
GB2126820A.
:
This invention was intended to provide a transducer elQment useable in an array. Although GB2126820A d als mainly with multiplexed systems it was intended to produce an element useable in any system whether multiplexed or not.
The invention provides a transducer comprising a , .~ , . . .
2 ~ 7 9 plurality of coils of optical fibre optically linked to form a single light path and encapsulated together within a solid material.
This provides a transducer element with improved rejection at high acoustic wavenumbers.
; The invention will now be descri*ed by way of example only with reference to the accompanying diagrammat:ic figures in which~
Figure 1 shows a known transducer element;
~: Figure 2 shows an array of transducer elements;
Figure 3 shows a first transducer element according to the~invention;
Figure 4 shows a second transducer element according to the:invention.
Referring to Figure 1 a known optical fibre pressure ~ sensor eLement is shown. This comprises a coil of optical ; ~: fibre 1 encapsulated with an encapsulating material 2 such as an epoxy resin. Where the sensor is to be included in a :
. , . : .-: : - . ~; -: . - : . ~ :
2~S9~79 hydrophone array extra encapsulating material can be added to overpot the coil and form a square tile 3. Optical signals can pass into the coil along ~ree end lA o~ the optical fibre 1, and out of the coil along free end lB of the optical fibre 1. As is well known, such a sensor operates by changes in acoustic pressure altering the optical path length of the fibre coil and thus altering the time taken ~or light to pass through the coil.
Such a sensor element can be produced by winding the optical fibre onto a mandrel and then removing the mandrel and encapsulating the coil in epoxy resin.
Although a hydrophone array can be formed by a plurality of such sensor elements linked in optical series they give poor rejection at high acoustic wavenu~bers.
A typical array of hydrophone sensor elements 3 is shown in Figuxe 2 where a plurality of sensor element 3 are towed~behind a ship 14 on a buoyant cable 15. In order to reduc~ the loads on the cable 15 the hydrophones 3 are constructed to be neutrally buoyant. The cable 15 carries a fibre op~ic cable to link all of the coils 1 as well as securing the sensor elements 3 to the ship 14.
:, ., : ~ - ; : ....
: : i ~, ..
20~79 :
It has been realised that the rej~ction of low noise by a pressure sensor element could be i.mproved by replacing the single coil with several smaller coplanar coils as shown in Figure 3~
Four coils 4 are arranged in a coplanar group with their axes of symmetry 4E parallel to form a single sensor element. The coils 4 are arranged in a sguare array in a :plane perpendicular to their axes of symmetry 4E. Each coil 4 consists of a coiled optical fibre 4A encapsulated by an epoxy resin 4B~ Of course another suitable encapsulating material could be used instead of epoxy resin. All ~our coils 4 are linked to a splicer box 5 by free ends o~ their respective coiled optica} fibre 4A. A free end 4C of one o~
the coiled optical fibres 4A in~one o~ the coils 4 acts as an optical ~input for the sensor element, and a ~ree end 4D
::
: ~ ` of the coiled optical fibre 4A in another one of the coils 4 : a~ts as an optical output for the sensor element.
Al1 four coils 4, the splicer box 5 and a11 of the free ~ibre ends are encapsulated in suitable material 6 to form a ~quare tile 7.
The input and output fibre ends 4C and 4D are each covered by a layer of armour 8 to protect them, the ends 8A
~: :
' 1 "~ ~ " , ' . , :~ . " ~ : . , .
.: ~ -: . . , , , ~ :, ~ .
. .: :, . .. . .. .
: :. . ~ : . -~ -:: ~. . :. : . :.
` 2~9579 P/8699~P48/CA
of this armour g are also encapsulated by the elastomeric material 6.
Tha splicer box 5 contains couplers to link all four coils 4 together optically in series and allows any strain acting on the tile 7 to be relieved without placing strain on the optical fibres 4A by allowing relative movement of ~ibres 4A and a reflective splice as described in GB2126820A. Alternatively the reflective splice could be incorporated outside the structure shown.
It has also been reaLised that another method of improving the rejectîon of flow noise: would be to replace the siDgle: coil: with a plurality of paraLlel coils:as shown~
, in~Figure 4.
: Four :coils: 10 are arranged side by side with their ~: : ~ : : : :
axes of symmetry lOF ~ in paralLeL ~and coplanar to form a single sensor element.
All four coiLs 10 are formed by a single optical fibre lOC which:links~:them into~a slngle optical struc~ure and has a first free end lOD ~orming:an optical input line, and a , second free end loE forming an optical output lin , both ~ ~ .
; ~ free ends lOD and lOE are protected by armoured sheaths 11.
:: ~ :
::
..
:, ,: , .
- : - : . ~:: . :, . , , :, :: . :
:;: , - . . . .
206~7~
P/8699/P~8/C~
The coils 10 and sheath 11 are encapsulated in an acoustically compatible material 12 to form a square tile ~3.
Although four coils are shown in both examples any number could be used.
The coils in the example of Figure 4 can be formed by winding an optical fibre onto a single mandrel and then splittiny the mandrel to produce four separate coils linked by a single fibre.
The use or not of a splicer box is an option whose desirability depends on the application for which the hydr~phone is to be used, thus the example in Figure 4 could use separate coils linked~by~a splicer box, similarly the example shown in Figure~3 could be formed by one continuous fibre by winding an optical fibre onto a mandrel as :
described above.
:: :
In all cases the mandrels could be left within the coils and enoapsulated with them.
:
The systems shown are transmissive with separate input - :
., ~ - :
: . .. .; ~ , :
2~6~579 and output fibres, the invention would be equally applicable to reflective systems having a single input and output ~ibre.
In all cases the encapsulating material forming the square tiles 13 could contain internal sti~ening to ensure that all resonance frequencies of the structure are ~utside the operating band of the hydrophone system~
: ~ ~ .:. . ., :.: .. , : . ~, - ,, .
-- 1 .
Improvements Relatin~ to Transducers This invention relates to transducers (e.g.
hydrophones) and relates more specifically to transducers comprising optical fibres forming part of an array.
Arrays o~ large area hydrophones require large numbers o~ individual transducers.
Large area hydrophones are currently in use or proposed for sonar systems which need large filled apertures and which required good rejection at high acoustic wavenumbers in order to reject flow noise~
Optical flbre transducers for use in hydrophones are known, for example in~our co-pending patent application No.
GB2126820A.
:
This invention was intended to provide a transducer elQment useable in an array. Although GB2126820A d als mainly with multiplexed systems it was intended to produce an element useable in any system whether multiplexed or not.
The invention provides a transducer comprising a , .~ , . . .
2 ~ 7 9 plurality of coils of optical fibre optically linked to form a single light path and encapsulated together within a solid material.
This provides a transducer element with improved rejection at high acoustic wavenumbers.
; The invention will now be descri*ed by way of example only with reference to the accompanying diagrammat:ic figures in which~
Figure 1 shows a known transducer element;
~: Figure 2 shows an array of transducer elements;
Figure 3 shows a first transducer element according to the~invention;
Figure 4 shows a second transducer element according to the:invention.
Referring to Figure 1 a known optical fibre pressure ~ sensor eLement is shown. This comprises a coil of optical ; ~: fibre 1 encapsulated with an encapsulating material 2 such as an epoxy resin. Where the sensor is to be included in a :
. , . : .-: : - . ~; -: . - : . ~ :
2~S9~79 hydrophone array extra encapsulating material can be added to overpot the coil and form a square tile 3. Optical signals can pass into the coil along ~ree end lA o~ the optical fibre 1, and out of the coil along free end lB of the optical fibre 1. As is well known, such a sensor operates by changes in acoustic pressure altering the optical path length of the fibre coil and thus altering the time taken ~or light to pass through the coil.
Such a sensor element can be produced by winding the optical fibre onto a mandrel and then removing the mandrel and encapsulating the coil in epoxy resin.
Although a hydrophone array can be formed by a plurality of such sensor elements linked in optical series they give poor rejection at high acoustic wavenu~bers.
A typical array of hydrophone sensor elements 3 is shown in Figuxe 2 where a plurality of sensor element 3 are towed~behind a ship 14 on a buoyant cable 15. In order to reduc~ the loads on the cable 15 the hydrophones 3 are constructed to be neutrally buoyant. The cable 15 carries a fibre op~ic cable to link all of the coils 1 as well as securing the sensor elements 3 to the ship 14.
:, ., : ~ - ; : ....
: : i ~, ..
20~79 :
It has been realised that the rej~ction of low noise by a pressure sensor element could be i.mproved by replacing the single coil with several smaller coplanar coils as shown in Figure 3~
Four coils 4 are arranged in a coplanar group with their axes of symmetry 4E parallel to form a single sensor element. The coils 4 are arranged in a sguare array in a :plane perpendicular to their axes of symmetry 4E. Each coil 4 consists of a coiled optical fibre 4A encapsulated by an epoxy resin 4B~ Of course another suitable encapsulating material could be used instead of epoxy resin. All ~our coils 4 are linked to a splicer box 5 by free ends o~ their respective coiled optica} fibre 4A. A free end 4C of one o~
the coiled optical fibres 4A in~one o~ the coils 4 acts as an optical ~input for the sensor element, and a ~ree end 4D
::
: ~ ` of the coiled optical fibre 4A in another one of the coils 4 : a~ts as an optical output for the sensor element.
Al1 four coils 4, the splicer box 5 and a11 of the free ~ibre ends are encapsulated in suitable material 6 to form a ~quare tile 7.
The input and output fibre ends 4C and 4D are each covered by a layer of armour 8 to protect them, the ends 8A
~: :
' 1 "~ ~ " , ' . , :~ . " ~ : . , .
.: ~ -: . . , , , ~ :, ~ .
. .: :, . .. . .. .
: :. . ~ : . -~ -:: ~. . :. : . :.
` 2~9579 P/8699~P48/CA
of this armour g are also encapsulated by the elastomeric material 6.
Tha splicer box 5 contains couplers to link all four coils 4 together optically in series and allows any strain acting on the tile 7 to be relieved without placing strain on the optical fibres 4A by allowing relative movement of ~ibres 4A and a reflective splice as described in GB2126820A. Alternatively the reflective splice could be incorporated outside the structure shown.
It has also been reaLised that another method of improving the rejectîon of flow noise: would be to replace the siDgle: coil: with a plurality of paraLlel coils:as shown~
, in~Figure 4.
: Four :coils: 10 are arranged side by side with their ~: : ~ : : : :
axes of symmetry lOF ~ in paralLeL ~and coplanar to form a single sensor element.
All four coiLs 10 are formed by a single optical fibre lOC which:links~:them into~a slngle optical struc~ure and has a first free end lOD ~orming:an optical input line, and a , second free end loE forming an optical output lin , both ~ ~ .
; ~ free ends lOD and lOE are protected by armoured sheaths 11.
:: ~ :
::
..
:, ,: , .
- : - : . ~:: . :, . , , :, :: . :
:;: , - . . . .
206~7~
P/8699/P~8/C~
The coils 10 and sheath 11 are encapsulated in an acoustically compatible material 12 to form a square tile ~3.
Although four coils are shown in both examples any number could be used.
The coils in the example of Figure 4 can be formed by winding an optical fibre onto a single mandrel and then splittiny the mandrel to produce four separate coils linked by a single fibre.
The use or not of a splicer box is an option whose desirability depends on the application for which the hydr~phone is to be used, thus the example in Figure 4 could use separate coils linked~by~a splicer box, similarly the example shown in Figure~3 could be formed by one continuous fibre by winding an optical fibre onto a mandrel as :
described above.
:: :
In all cases the mandrels could be left within the coils and enoapsulated with them.
:
The systems shown are transmissive with separate input - :
., ~ - :
: . .. .; ~ , :
2~6~579 and output fibres, the invention would be equally applicable to reflective systems having a single input and output ~ibre.
In all cases the encapsulating material forming the square tiles 13 could contain internal sti~ening to ensure that all resonance frequencies of the structure are ~utside the operating band of the hydrophone system~
: ~ ~ .:. . ., :.: .. , : . ~, - ,, .
Claims (6)
1. A transducer comprising a plurality of coils of optical fibre optically linked to form a single light path and encapsulated together with a solid material.
2. A transducer as claimed in claim 1 where the coils are cylindrical and have parallel axes of symmetry.
3. A transducer as claimed in claim 1 or claim 2 where the coils are arranged to form an array in a plane perpendicular to their axes of symmetry.
4. A transducer as claimed in claim 1 or claim 2 where the coils; are arranged with their axes of symmetry coplanar.
5. A transducer as claimed in any preceding claim where there are four transducers.
6. A transducer as claimed in any preceding claim where all of the coils are formed from and linked by a single continuous optical fibre.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9112106.1 | 1991-06-05 | ||
| GB919112106A GB9112106D0 (en) | 1991-06-05 | 1991-06-05 | Improvements relating to transducers |
| GB9208862.4 | 1992-04-24 | ||
| GB9208862A GB2256561A (en) | 1991-06-05 | 1992-04-24 | Large area optical fibre hydrophone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2069579A1 true CA2069579A1 (en) | 1992-12-06 |
Family
ID=26299016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2069579 Abandoned CA2069579A1 (en) | 1991-06-05 | 1992-05-26 | Transducers |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2069579A1 (en) |
| FR (1) | FR2681495A1 (en) |
| GB (1) | GB2256561A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426054B (en) * | 2011-10-29 | 2013-01-16 | 中北大学 | Monolithic integration composite range vector hydrophone |
| CN105300505A (en) * | 2015-10-14 | 2016-02-03 | 中国船舶重工集团公司第七一五研究所 | Wide-band high-sensitivity planar optical fiber vector hydrophone |
| CN106323439B (en) * | 2016-08-01 | 2020-07-14 | 北京航天控制仪器研究所 | Time-delay optical fiber and reference optical fiber packaging structure for optical fiber hydrophone modulation system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4311391A (en) * | 1979-12-27 | 1982-01-19 | Westinghouse Electric Corp. | Passive fiber optic sonar system |
| US4534222A (en) * | 1983-08-08 | 1985-08-13 | Mcdonnell Douglas Corporation | Fiber-optic seismic sensor |
| US4639138A (en) * | 1984-10-29 | 1987-01-27 | Martin Marietta Corporation | Fiber-optic rotation rate sensor having dual interferometer loops |
| US5051965A (en) * | 1985-04-19 | 1991-09-24 | Western Atlas International, Inc. | Acousto-optical marine sensor array |
| US4799752A (en) * | 1987-09-21 | 1989-01-24 | Litton Systems, Inc. | Fiber optic gradient hydrophone and method of using same |
| US5012088A (en) * | 1989-03-31 | 1991-04-30 | Cole James H | High performance fiber optic sensor |
| US4994668A (en) * | 1989-09-01 | 1991-02-19 | The United States Of America As Represented By The Secretary Of The Navy | Planar fiber-optic interferometric acoustic sensor |
| US5074665A (en) * | 1989-12-21 | 1991-12-24 | Andrew Corporation | Fiber optic gyroscope using dual-section counter-wound coil |
-
1992
- 1992-04-24 GB GB9208862A patent/GB2256561A/en not_active Withdrawn
- 1992-05-26 CA CA 2069579 patent/CA2069579A1/en not_active Abandoned
- 1992-06-04 FR FR9206793A patent/FR2681495A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB9208862D0 (en) | 1992-06-10 |
| GB2256561A (en) | 1992-12-09 |
| FR2681495A1 (en) | 1993-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU748184B2 (en) | Fiber optic sensor system and method | |
| US6211964B1 (en) | Method and structure for incorporating fiber optic acoustic sensors in a seismic array | |
| US8988968B2 (en) | Seismic cable structure | |
| US6195162B1 (en) | Seismic sensor with interferometric sensing apparatus | |
| US6108267A (en) | Non-liquid filled streamer cable with a novel hydrophone | |
| US6188645B1 (en) | Seismic sensor array with electrical-to optical transformers | |
| US5600608A (en) | Hydrophone carrier | |
| AU2008202686B2 (en) | Seismic streamer having longitudinally symmetrically sensitive sensors to reduce effects of longitudinally traveling waves | |
| US6346985B1 (en) | Optical method for the transduction of remote arrays of electromechanical sensors | |
| US20120227504A1 (en) | Fiber optic acoustic sensor arrays and systems, and methods of fabricating the same | |
| US5883857A (en) | Non-liquid filled streamer cable with a novel hydrophone | |
| EP0066493A1 (en) | Pressure wave fiber optic transducer cable | |
| EP0765485A1 (en) | Semi-dry marine seismic streamer cable section | |
| EP1546773A2 (en) | Rugged fiber optic array | |
| US4524436A (en) | Pressure wave fiber optic transducer cable | |
| US6256588B1 (en) | Seismic sensor array with electrical to optical transformers | |
| CN100349026C (en) | Rugged fiber optic array | |
| EP1481225B1 (en) | Optical fibre sensor assembly | |
| CA2069579A1 (en) | Transducers | |
| US6661741B1 (en) | Optical hydrophone and array using bubble resonance for detecting acoustic signals | |
| AU680489B2 (en) | Hydrophone carrier | |
| US20200073069A1 (en) | Fiber optic sensor and system including a fiber of an optical cable as a sensor fiber | |
| GB2137767A (en) | Optical fibre transducer | |
| JPS61151485A (en) | Optical fiber hydrophone | |
| MXPA00007196A (en) | Fiber optic sensor system and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |