GB2447966A - Optical fibre chemical sensor - Google Patents
Optical fibre chemical sensor Download PDFInfo
- Publication number
- GB2447966A GB2447966A GB0706202A GB0706202A GB2447966A GB 2447966 A GB2447966 A GB 2447966A GB 0706202 A GB0706202 A GB 0706202A GB 0706202 A GB0706202 A GB 0706202A GB 2447966 A GB2447966 A GB 2447966A
- Authority
- GB
- United Kingdom
- Prior art keywords
- optical
- chemically responsive
- chemical sensor
- sensor according
- chemical
- 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.)
- Granted
Links
- 239000000126 substance Substances 0.000 title claims abstract description 64
- 239000013307 optical fiber Substances 0.000 title claims abstract description 25
- 230000003287 optical effect Effects 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims abstract description 32
- 238000005253 cladding Methods 0.000 claims abstract description 17
- 229920000642 polymer Polymers 0.000 claims abstract description 16
- 239000011159 matrix material Substances 0.000 claims abstract description 12
- 239000002245 particle Substances 0.000 claims abstract description 12
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000002105 nanoparticle Substances 0.000 claims abstract description 9
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 3
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 3
- 239000010948 rhodium Substances 0.000 claims abstract description 3
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims abstract description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000000835 fiber Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 5
- 238000005459 micromachining Methods 0.000 claims description 5
- 230000009977 dual effect Effects 0.000 claims description 2
- 239000004814 polyurethane Substances 0.000 claims description 2
- 229920002635 polyurethane Polymers 0.000 claims description 2
- 230000003993 interaction Effects 0.000 claims 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims 1
- 239000004926 polymethyl methacrylate Substances 0.000 claims 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000000253 optical time-domain reflectometry Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013626 chemical specie Substances 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- -1 palladium hydride Chemical class 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/7703—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides
- G01N21/774—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides the reagent being on a grating or periodic structure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/7703—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y15/00—Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/7703—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator using reagent-clad optical fibres or optical waveguides
- G01N2021/7706—Reagent provision
- G01N2021/773—Porous polymer jacket; Polymer matrix with indicator
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/12—Circuits of general importance; Signal processing
- G01N2201/121—Correction signals
- G01N2201/1211—Correction signals for temperature
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Analytical Chemistry (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Nanotechnology (AREA)
- Molecular Biology (AREA)
- Crystallography & Structural Chemistry (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
Abstract
An optical chemical sensor comprising: an optical fibre having a core and a cladding layer (3) and a recess (4) in the cladding layer (3) containing chemically responsive material; the recess (4) being arranged so that at least part of the chemically responsive material interacts with the evanescent field of light passing along the optical fibre; the chemically responsive material having a bulk refractive index close to a refractive index of the core and comprising a polymer matrix loaded with chemically responsive particles, such that the chemically responsive particles respond to the presence of a particular chemical by changing the optical properties of the chemically responsive material. The chemically responsive material may be a nanoparticle of titanium oxide, palladium, platinum or rhodium embedded in a polymer matrix such as an interpenetrating polymer network (IPN).
Description
* I 2447966 Improved Optical Chemical Sensor The present invention
relates to improvements to optical chemical sensors, and in particular to fibre optic chemical sensors.
The use of optical fibres to carry optical signals from sensors to equipment responding to the conditions detected by the sensors, such as automatic control devices or user displays is well known, as are the many advantages over the use of electrical signals such as immunity to electrical interference, rapid response, remote control, distributed multipoint sensing and fire safety.
Currently, sensors that are intended to detect chemicals are electrical in nature. These electrical sensors are typically relatively large in size, and have a complex mode of operation.
Further, they require a power supply close to the sensing location.
In order to overcome this problem the present invention was intended to provide a cheap and simple chemical sensor which indicates sensing of specific chemicals by an optical signal, is passive in nature, and does not require any power supply at the sensing location.
In a first aspect this invention provides: an optical chemical sensor comprising: an optical fibre having a core and a cladding layer and a recess in the cladding layer containing chemically responsive material; the recess being arranged so that at least part of the chemically responsive material interacts with the evanescent field of light passing along the optical fibre; the chemically responsive material having a bulk refractive index close to a refractive index of the core and comprising a polymer matrix loaded with chemically responsive particles, such that the chemically responsive particles respond to the presence of a particular chemical by changing the optical properties of the chemically responsive material.
The change in optical properties can preferably be a change of bulk refractive index or a change in optical absorption properties. Such changes will in turn effect the light transmission in the core of the fiber by either absorption or change in refractive index.
In a second aspect, the invention provides a method of producing an optical chemical sensor according to th eflrst aspect in which the or each recess is formed by laser micromachining.
The chemical sensor according to the present invention is cheap, robust and simple to manufacture and allows sensing of specific chemicals by change in optical signals Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic figures, in which: Figure 1 shows a general view of an optical fibre; Figure 2 shows a sectional view of an optical fibre with a recess accessing the evanescent
field;
Figure 3 shows a perspective view of the optical fibre of figure 2; Figure 4 shows a sectional view of a first optical chemical sensor according to the invention; Figure 5 shows a ftirther sectional view of the optical chemical sensor of figure 4; Figure 6 shows a sectional view of a second optical chemical sensor according to the invention; and Figure 7 shows a view of the optical chemical sensor of figure 4 in more detail.
A cross section through an optical fibre suitable for use in the present invention is shown in figure 1. The optical fibre 1 comprises a fibre core 2 surrounded by a cladding layer 3. The fibre 1 acts as a dielectric waveguide for optical signals passing along the fibre I and with an evanescent field or decaying field which extends into the cladding layer 3 from the fibre core 2. If a part of the cladding layer 3 is removed to form a recess so that the evanescent field can be accessed, it is then possible to change the properties of the light passing along the fibre I by changing the conditions encountered by the exposed part of the evanescent field within the recess.
The characteristic of the light which is affected will depend on the precise characteristics of the optical fibre I, the degree of exposure of the evanescent field and the changes made in the conditions experienced by the evanescent field. Typically the light level or the polarisation of light transmitted along the core or the amount of light reflected back along the fibre] will be changed.
One typical example of an optical fibre 1 has a core 2 about 10 microns in diameter surrounded by a cladding layer 3 with a thickness of about 125 microns. When light passes along the fibre I the evanescent field will typically extend from the core 2 about I or 2 microns into the cladding layer 3.
This example is purely illustrative and use of these specific dimensions is not essential.
As shown in figures 2 and 3, one or more recesses 4 are opened in the cladding layer 3 of the fibre 1, the recesses 4 having sufficient depth to expose the evanescent field of light passing along the fibre 1.
Preferably the recesses 4 in the cladding 3 of the fibre I are formed by laser micro machining to form recesses of a desired shape and size. However, other methods of removing cladding material to expose the evanescent field are known, for example grinding and polishing the optical fibre 1. The use of laser micro machining is generally preferred in order to increase repeatability and yield and to allow recesses 4 with a defined shape and size to be provided.
Laser micro machining allows a large number of small recesses 4 to be formed, increasing the sensitivity and versatility of the sensor. Use of a laser micro machine method according to G2407055B is particularly preferred.
In order to cause a recess 4 to act as a chemical sensor responsive to the presence of a desired chemical the recess 4 is at least partially filled with a layer 5 of a chemically responsive material, as shown in figure 4. The chemically responsive material comprises a matrix of polymer material loaded or impregnated with nanoparticles formed of a material reactive to the presence of the chemical species desired to be sensed.
The refractive indexes of the polymer matrix and the nanoparticles and the loading quantity of the nanoparticles are selected so that the loaded polymer matrix forming the chemically responsive material has a bulk or average refractive index similar to or matching the refractive index of the cladding layer 3 of the optical fibre 1. When the chemical to be sensed by the sensor is present the nanoparticles react, changing the average refractive index of the chemically responsive material. This change in refractive index effects the evanescent field of optical signals passing along the optical fibre 1, producing a change in the intensity or polarisation of the transmitted and/or reflected optical signals which can be detected in order to sense the presence of the chemical. If the starting refractive index of the polymer matrix is matched to the core of the optical fiber, when the refractive index of the loaded polymer matrix changes in response to the presence of the chemical to be detected, a large change in the optical signal transmitted in the fiber will be observed.
One example of a chemical sensor according to the invention is a chemical sensor to detect hydrogen. This has a chemically responsive material formed from a mixture of polyurethane and polymethyImethacry1t formed as an interpenetrating polymer network (IPN). An IPN comprises two or more polymer networks that are partially interlaced on a molecular scale but are not covalently bonded to one another. The two networks cannot be separated without breaking chemical bonds. The IPN is loaded with nanoparticles of palladium a few tens of micrometers across in order to make it sensitive to hydrogen.
When hydrogen is present the palladium of the palladium nanoparticles is converted to palladium hydride, changing the refractive index of the loaded polymer matrix,changing the refractive index of the chemically responsive material, and so producing a measurable change in the optical transmission properties of the optical fibre indicating the presence of hydrogen.
Other polymers having suitable optical properties could also be used. The nanopartjcles could be formed of other materials, such as titanium oxide, platinum or rhodium for example, or mixtures of materials, to detect different chemicals. The size and shape of the nanopartjcles can be varied depending on the material or materials they are formed from and how this reacts to the chemical intended to be detected in order to best translate this reaction into a change in refractive index of the chemically responsive material. The nanoparticles can respond to the presence of the chemical by changing their chemical or physical structure.
lithe chemical sensors are distributed along the optical fibre, the location at which the chemical has been sensed, that is the location of the sensor detecting the chemical, can be determined, This can for example be carried out by known techniques such as optical time domain reflectometry (OTDR).
One possibility is to form sensors with different chemically responsive materials to detect different chemicals distributed along an optical fibre. By using OTDR to determine where a change in refractive index, polarisatjon or absorption has taken place, the reacting sensor, and thus the identity of the chemical being detected, can be determined.
in order to compensate for changes in the optical properties of the sensor caused by temperae changes the arrangement shown in figure 6 can be used. This uses a dual core optical fibre 10 with a first core 11 and a second core 12, both surrounded by a common cladding layer 13.
The cladding layer 13 has recesses 14 used to form chemical sensors accessing the evanescent field of the first core 11 only. The second core 12 has Bragg gratings 15 written onto it by laser adjacent to the chemical sensors of the first core 11.
Changes in temperature cause material of the first and second cores 11 and 12 to expand and contract, causing the spacing between the elements of the Bragg gratings 15 to change. This change in spacing can be remotely optically measured to determine the temperature at a chemical sensor apparently detecting chemicals so that any changes in optical properties caused by changes in temperature can be compensated for.
The embodimenis and examples of the invention described above are not intended to be exhaustive and the scope of the invention is set out in the appended claims.
Claims (1)
- Claims 1. An optical chemical sensor comprising: an optical fibrehaving a core and a cladding layer and a recess in the cladding layer containing chemically responsive material; the recess being arranged so that at least part of the chemically responsive material interacts with the evanescent field of light passing along the optical fibre; the chemically responsive material having a bulk refractive index close to a refractive index of the core and comprising a polymer matrix loaded with chemically responsive particles, such that the chemically responsive particles respond to the presence of a particular chemical by changing the optical properties of the chemically responsive material 2. The optical chemical sensor according to claim 1, in which the chemically responsive particles respond to the presence of a particular chemical by changing the bulk refractive index of the chemically responsive material 3. The optical chemical sensor according to claim I, in which the chemically responsive particles respond to the presence of a particular chemical by changing the optical absorbtion properties of the chemically responsive material 4. The optical chemical sensor according to any preceding claim, in which the chemically responsive particles are nanoparticles.5. The optical chemical sensor according to any preceding claim, in which the chemically responsive particles respond to the presence of a particular chemical by changing their chemical structure.6 The optical chemical sensor according to any one of claims I to 5, in which the chemically responsive particles respond to the presence of a particular chemical by changijg their physical structure 7. The optical chemical sensor according to any preceding claim, in which the bulk refractive index of the chemically responsive material matches the refractive index of the core.8. The optical chemical sensor according to any preceding claim, in which the -chemically responsive particles are formed of one of: titanium oxide, palladium, platinum or rhodium.9. The optical chemical sensor according to any preceding claim, in which the polymer matrix comprises an interpenetrating polymer network.10. The optical chemical sensor according to claim 6, in which the polymer matrix is formed by polyurethane and polymethylmethacrylate 811. The optical chemical sensor according to any preceding claim, in which the optical fibre is a dual core fibre and the second core has a Bragg grating located adjacent the chemical sensor.12 The optical chemical sensor according to any preceding claim, in which the change in properties of the chemically responsive material is detected by evanescent field interactions in the optical fiber.13. A plurality of chemical sensors according to any preceding claim spaced along a single optical fibre.I 4.The plurality of optical chemical sensors according to claim 12, in which different ones of the chemical sensors respond to different particular chemicals.IS A method of producing an optical chemical sensor according to any preceding claim in which the or each recess is formed by laser micromachining.16. An optical chemical sensor substantially as shown in or as described with reference to any of figures 4 to 7 of the drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0706202A GB2447966B8 (en) | 2007-03-29 | 2007-03-29 | Improved optical chemical sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0706202A GB2447966B8 (en) | 2007-03-29 | 2007-03-29 | Improved optical chemical sensor |
Publications (4)
| Publication Number | Publication Date |
|---|---|
| GB0706202D0 GB0706202D0 (en) | 2007-05-09 |
| GB2447966A true GB2447966A (en) | 2008-10-01 |
| GB2447966B GB2447966B (en) | 2012-01-25 |
| GB2447966B8 GB2447966B8 (en) | 2012-02-08 |
Family
ID=38050515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0706202A Expired - Fee Related GB2447966B8 (en) | 2007-03-29 | 2007-03-29 | Improved optical chemical sensor |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2447966B8 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279438A (en) * | 2011-07-25 | 2011-12-14 | 中国科学院光电技术研究所 | Optical fiber evanescent field sensing optical fiber with novel micro-nano structure |
| FR3011940A1 (en) * | 2013-10-16 | 2015-04-17 | Andra | OPTICAL FIBER, METHOD FOR MANUFACTURING SUCH AN OPTICAL FIBER, AND MEASURING DEVICE FOR DETECTION OF HYDROGEN EQUIPPED WITH SUCH AN OPTICAL FIBER |
| WO2016050895A1 (en) * | 2014-10-02 | 2016-04-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for determining a refractive index |
| WO2019116035A1 (en) * | 2017-12-12 | 2019-06-20 | Oxford Caresense Ltd. | Sensor including an optical fibre and its use in wetness monitoring |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4600310A (en) * | 1981-03-30 | 1986-07-15 | Imperial Chemical Industries Plc | Optical fibre sensor |
| WO1986005589A1 (en) * | 1985-03-20 | 1986-09-25 | Monash University | Fibre optic chemical sensor |
| EP0234928A2 (en) * | 1986-02-27 | 1987-09-02 | Eli Lilly And Company | Optical fiber apparatus |
| US5747348A (en) * | 1995-07-05 | 1998-05-05 | The Aerospace Corporation | Diode laser interrogated fiber optic hydrazine-fuel sensor |
| US6328932B1 (en) * | 1997-05-08 | 2001-12-11 | Eltron Research, Inc. | Devices and methods for the detection of basic gases |
| US6531097B1 (en) * | 1997-11-03 | 2003-03-11 | Cancer Research Campaign Technology, Ltd. | Measuring the concentration of a substance |
| WO2003071235A1 (en) * | 2002-02-20 | 2003-08-28 | Institut National D'optique | Packaged optical sensors on the side of optical fibres |
| WO2006116590A1 (en) * | 2005-04-28 | 2006-11-02 | Claudio Oliveira Egalon | Improved reversible, low cost, distributed optical fiber sensor with high spatial resolution |
-
2007
- 2007-03-29 GB GB0706202A patent/GB2447966B8/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4600310A (en) * | 1981-03-30 | 1986-07-15 | Imperial Chemical Industries Plc | Optical fibre sensor |
| WO1986005589A1 (en) * | 1985-03-20 | 1986-09-25 | Monash University | Fibre optic chemical sensor |
| EP0234928A2 (en) * | 1986-02-27 | 1987-09-02 | Eli Lilly And Company | Optical fiber apparatus |
| US5747348A (en) * | 1995-07-05 | 1998-05-05 | The Aerospace Corporation | Diode laser interrogated fiber optic hydrazine-fuel sensor |
| US6328932B1 (en) * | 1997-05-08 | 2001-12-11 | Eltron Research, Inc. | Devices and methods for the detection of basic gases |
| US6531097B1 (en) * | 1997-11-03 | 2003-03-11 | Cancer Research Campaign Technology, Ltd. | Measuring the concentration of a substance |
| WO2003071235A1 (en) * | 2002-02-20 | 2003-08-28 | Institut National D'optique | Packaged optical sensors on the side of optical fibres |
| WO2006116590A1 (en) * | 2005-04-28 | 2006-11-02 | Claudio Oliveira Egalon | Improved reversible, low cost, distributed optical fiber sensor with high spatial resolution |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279438A (en) * | 2011-07-25 | 2011-12-14 | 中国科学院光电技术研究所 | Optical fiber evanescent field sensing optical fiber with novel micro-nano structure |
| CN102279438B (en) * | 2011-07-25 | 2013-04-03 | 中国科学院光电技术研究所 | Optical fiber evanescent field sensing optical fiber with micro-nano structure |
| FR3011940A1 (en) * | 2013-10-16 | 2015-04-17 | Andra | OPTICAL FIBER, METHOD FOR MANUFACTURING SUCH AN OPTICAL FIBER, AND MEASURING DEVICE FOR DETECTION OF HYDROGEN EQUIPPED WITH SUCH AN OPTICAL FIBER |
| WO2015055593A1 (en) * | 2013-10-16 | 2015-04-23 | Agence Nationale Pour La Gestion Des Déchets Radioactifs | Optical fibre, process for manufacturing such an optical fibre and measuring device equipped with such an optical fibre and intended to detect hydrogen |
| WO2016050895A1 (en) * | 2014-10-02 | 2016-04-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for determining a refractive index |
| US10184888B2 (en) | 2014-10-02 | 2019-01-22 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for determining a refractive index |
| WO2019116035A1 (en) * | 2017-12-12 | 2019-06-20 | Oxford Caresense Ltd. | Sensor including an optical fibre and its use in wetness monitoring |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0706202D0 (en) | 2007-05-09 |
| GB2447966B (en) | 2012-01-25 |
| GB2447966B8 (en) | 2012-02-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) |
Free format text: REGISTERED BETWEEN 20090723 AND 20090729 |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20170329 |