WO2021187972A1 - Capteur électromagnétique distribué à base de fibre optique et son procédé de fabrication - Google Patents

Capteur électromagnétique distribué à base de fibre optique et son procédé de fabrication Download PDF

Info

Publication number
WO2021187972A1
WO2021187972A1 PCT/MY2021/050017 MY2021050017W WO2021187972A1 WO 2021187972 A1 WO2021187972 A1 WO 2021187972A1 MY 2021050017 W MY2021050017 W MY 2021050017W WO 2021187972 A1 WO2021187972 A1 WO 2021187972A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical fiber
core
magnetostrictive materials
length
fiber sensor
Prior art date
Application number
PCT/MY2021/050017
Other languages
English (en)
Inventor
Ahmad Riza GHAZALI
M Faizal A RAHIM
Mohd Fahmi AZMAN
Hairul Azhar AB RASHID
M Hafizal MD ZAHIR
Mohd Ridzuan MOKHTAR
Original Assignee
Petroliam Nasional Berhad (Petronas)
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Petroliam Nasional Berhad (Petronas) filed Critical Petroliam Nasional Berhad (Petronas)
Publication of WO2021187972A1 publication Critical patent/WO2021187972A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
    • G02B6/03694—Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/026—Drawing fibres reinforced with a metal wire or with other non-glass material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
    • G01R29/0878—Sensors; antennas; probes; detectors
    • G01R29/0885—Sensors; antennas; probes; detectors using optical probes, e.g. electro-optical, luminescent, glow discharge, or optical interferometers

Definitions

  • the present invention relates to an optical fiber sensor, more particularly, to an optical fiber based distributed electromagnetic sensor capable of electromagnetic signal measurements along a length of the fiber.
  • optical fiber sensors operating based on the analysis of backscattered light have been developed for providing information about environmental conditions including temperature, pressure, force, strain, and other parameters in harsh environments such as oil and gas pipes or subterranean oil wells.
  • Optical fibers operating based on the same backscattered light principle can also be used for electromagnetic sensing in oil and gas pipes and subterranean oil wells.
  • There are two different types of optical fiber based electromagnetic sensors which are point type or quasi-distributed optical fiber based electromagnetic sensors and distributed optical fiber based electromagnetic sensors.
  • the point type or quasi-distributed optical fiber based electromagnetic sensor is provided with a magnetic material attached to the fiber at specific locations to detect localized electromagnetic signals near the magnetic material.
  • the existing distributed optical fiber based electromagnetic sensor includes a sensing fiber and a reference fiber, the pair of fibers running alongside each other to detect the electromagnetic signals along a length of the fiber using interferometric sensing principle.
  • the electromagnetic measurements obtained using the interferometric sensing principle may not be accurate as it is susceptible to input power fluctuations.
  • a typical optical fiber electromagnetic sensor includes a fiber optic cable structure having an optical fiber disposed within at least one jacket layer.
  • a conductive wire comprising a conductive core is arranged within the jacket layer of the fiber optical cable structure.
  • the conductive wire may comprise a magnetostrictive material, for instance nickel or steel that runs along a significant length of the optical fiber.
  • Each sensing portion in the fiber optic sensor generates a measurement signal indicative of the variation in the backscattered radiation corresponding with the electric current applied for that sensing portion, providing a distributed environmental fibre optic sensor.
  • the fiber optic sensor is susceptible to input power fluctuations and has minimal electromagnetic sensitivity as it includes only a single conductive wire running alongside the optical fiber.
  • optical fiber electromagnetic sensor includes an optically conductive fiber core, surrounded by a fiber cladding, an electrically conductive layer and an outer magnetostrictive layer electroplated onto the electrically conductive layer.
  • the magnetostrictive layer is a continuous layer of nickel alloy arranged concentrically around the central core. The sensing principle is based on the analysis of backscattered optical radiation from within the optical fiber. However, the multiple layers around the core increases the size of the optical fiber sensor.
  • An aim of the invention therefore is to provide an optical fiber based distributed electromagnetic sensor with size similar to a standard optical fiber and capable of electromagnetic signal measurements with high sensitivity along a length of the fiber.
  • an optical fiber sensor for measuring distributed electromagnetic signals along a length of the optical fiber, comprising: a core for guiding optical signals along a length of the core; and a cladding layer including a plurality of magnetostrictive materials disposed around the core; characterized in that the plurality of magnetostrictive materials are disposed parallel to and concentric with the core to induce strain upon magnetization of the magnetostrictive materials causing a frequency shift in Rayleigh backscattered signal through the core.
  • the plurality of magnetostrictive materials arranged in the cladding layer can expand or contract upon magnetization.
  • the expansion or contraction of the magnetostrictive materials causes frequency shift in the optical signal through the core which helps in measuring distributed electromagnetic signals along a length of the optical fiber.
  • a plurality of packing rods is disposed between the core and the magnetostrictive materials.
  • the cladding layer has a higher melting point compared to the magnetostrictive material arranged in the cladding layer.
  • this helps in fabrication of the optical fiber sensor without air gaps between the magnetostrictive material and the cladding layer.
  • the magnetostrictive materials are disposed in the cladding layer, parallel to and symmetrically around the core along the length of the optical fiber.
  • this helps in increased strain and distributed electromagnetic signal sensitivity anywhere along the length of the entire optical fiber.
  • the magnetostrictive material is provided together with an acrylic coating along a length of the optical fiber.
  • this functions as a protective layer for the optical fiber.
  • the optical fiber sensor can be used for distributed sensing of electromagnetic signals along the length of the optical fiber installed in subterranean regions, oil wells and other harsh environments.
  • a method of fabricating an optical fiber sensor for measuring distributed electromagnetic signals along a length of the optical fiber comprising: forming a multimode preform comprising a central core surrounded by a cladding layer; stacking a plurality of magnetostrictive materials around the multimode preform parallel to and concentric with the core along the length thereof to form a precursor fiber; heating the precursor fiber at a temperature exceeding the melting point of the magnetostrictive material; drawing the precursor fiber to an outer diameter of around 2-3mm while continuously applying vacuum to the top thereof; and further drawing the precursor fiber to an outer diameter of around 120-130pm to form the optical fiber sensor.
  • the precursor fiber has an outer diameter of about 2.5mm.
  • the optical fiber sensor has an outer diameter of about 125pm.
  • a plurality of packing rods is stacked around the multimode preform prior to the plurality of magnetostrictive materials being disposed therearound.
  • this helps to melt fill the voids during fabrication of the optical fiber sensor from the precursor fiber.
  • the magnetostrictive materials include nickel wires.
  • the cladding layer is silica based.
  • this helps in the fabrication of the multimode preform at temperatures exceeding 1400°C which melt fills the nickel wires within silica tube jackets.
  • the nickel wire has a lower melting temperature than the surrounding silica material, so pushing the nickel wires into the silica tube jackets while continuously applying vacuum to a top of the precursor fiber fills the melted nickel within the silica tube jackets without forming any air gaps.
  • the application of vacuum to the top of the precursor fiber during fabrication of the optical fiber sensor completely compress and close the interstitial holes between the silica cladding layer and the magnetostrictive materials placed around the multimode preform.
  • the plurality of magnetostrictive materials disposed in the cladding layer parallel to and around the core and extending along the length of the fiber also functions as a protective layer for the optical fiber sensor.
  • optical fiber sensor for measuring distributed electromagnetic signals is a single optical fiber with standard optical fiber size of 125pm diameter.
  • Figure 1(a) illustrates a schematic sectional view of a precursor fiber for fabrication of an optical fiber sensor according to an embodiment of the invention.
  • Figure 1(b) illustrates a schematic sectional view of an optical fiber sensor for measuring distributed electromagnetic signals along a length of the fiber according to an embodiment of the invention.
  • Figure 2 illustrates a flow diagram showing the steps involved in a method of fabricating the optical fiber sensor shown in Figure 1(b) for measuring distributed electromagnetic signals along a length of the fiber according to an embodiment of the invention.
  • Figures 3(a)-(c) illustrate schematic views of forced melt filling of magnetostrictive materials into the silica tube jackets according to an embodiment of the invention.
  • FIG. 1(a) there is illustrated a precursor fiber 20 with a plurality of components stacked around a multimode preform 22 for fabrication of an optical fiber sensor according to an embodiment of the invention.
  • the multimode preform 22 includes a central core 12 which is positioned at a centre of the precursor fiber 20.
  • the plurality of components stacked around the multimode preform 22 include a plurality of packing rods 24 and a plurality of magnetostrictive materials 16.
  • Each of the magnetostrictive materials 16 is inserted into a silica tube jacket 26 to prevent diffusion of the melted magnetostrictive material 16 into a structure of the optical fiber sensor during the fabrication process.
  • the plurality of components stacked around the multimode preform 22 are held in position using a special jig and polytetrafluoroethylene (PTFE) tape.
  • PTFE polytetrafluoroethylene
  • the precursor fiber 20 is first drawn to form an optical fiber cane with a size of approximately 2.5mm in outer diameter while continuously applying vacuum to a top of the precursor fiber 20 which completely compresses and closes the interstitial holes between the silica and the stacked components around the multimode preform 22.
  • the application of vacuum during the fabrication further helps to fix the magnetostrictive materials 16 inserted into the silica tube jacket 26.
  • the optical fiber cane is further drawn to an outer diameter of around 125 pm to form the optical fiber sensor which can be utilized for measuring distributed electromagnetic signals along the length of the fiber.
  • the two-stage fabrication of the optical fiber sensor helps to prevent the structural defects during the drawing process.
  • the optical fiber sensor 10 for measuring distributed electromagnetic signals along a length of the fiber according to an embodiment of the invention.
  • the optical fiber sensor 10 comprises a core 12 for guiding optical signals along a length of the core 12 and a cladding layer 14 including the plurality of magnetostrictive materials 16 disposed around the core 12.
  • the plurality of magnetostrictive materials 16 are disposed in the cladding layer 14, parallel to and concentric with the core 12 to induce intensified strain upon magnetization of the optical fiber.
  • the magnetization of the optical fiber expands or contracts the magnetostrictive materials 16 disposed in the cladding layer 14 inducing intensified strain on the optical fiber thereby causing a frequency shift in Rayleigh backscattered signal through the core 12.
  • the core 12 is fabricated from germanium doped silica glass (GeCh + S1O2) having a refractive index n x.
  • the core 12 is surrounded by the cladding layer 14 fabricated from silica (S1O2) having a refractive index of n 2 , (n 1 > n 2 ).
  • the plurality of magnetostrictive materials 16 disposed in the cladding layer 14 is fabricated from nickel wires.
  • the plurality of magnetostrictive materials 16 made from nickel wires and arranged in the cladding layer 14 can expand or contract upon magnetization.
  • the expansion or contraction of the magnetostrictive materials 16 causes frequency shift in the optical signal through the core 12 which helps in measuring distributed electromagnetic signals along a length of the optical fiber.
  • the magnetostrictive materials 16 are disposed in the cladding layer 14, parallel to and symmetrically around the core 12 along the length of the optical fiber.
  • the symmetric arrangement of the magnetostrictive materials 16 in the cladding layer 14 helps to induce increased strain on the optical fiber when magnetic field is applied.
  • the increased strain on the optical fiber further improves the sensitivity of the distributed electromagnetic signal measurements anywhere along the length of the entire optical fiber.
  • the magnetostrictive material 16 is provided together with an acrylic coating along a length of the optical fiber sensor 10.
  • the magnetostrictive material 16 along with the acrylic coating function as a protective layer for the optical fiber sensor 10.
  • the optical fiber sensor 10 can be used for distributed sensing of electromagnetic signals along the length of the optical fiber installed in subterranean regions, oil wells and other harsh environments. Magnetization of the optical fiber causes expansion or contraction of the nickel based magnetostrictive material 16 arranged in the cladding layer 14, which induces strain on the optical fiber causing a frequency shift in Rayleigh backscattered signal through the core 12. The frequency shift in Rayleigh backscattered signal through a selected portion of the core 12 is analysed to measure the distributed electromagnetic signal strength in that particular portion of the optical fiber.
  • FIG. 2 there is illustrated a flow diagram showing the steps involved in a method of fabricating the optical fiber sensor 10 for measuring distributed electromagnetic signals along the length of the fiber according to an embodiment of the invention.
  • the method of fabricating the optical fiber sensor 10 include the steps of forming a multimode preform 22 comprising a central core 12 surrounded by a cladding layer 14, as shown in block 100.
  • a plurality of magnetostrictive materials 16 are stacked around the multimode preform 22 parallel to and concentric with the core 12 along the length of the multimode preform 22 to form a precursor fiber 20 as in block 102.
  • a plurality of packing rods 24 are stacked around the multimode preform 22 parallel to and concentric with the core 12 prior to the arrangement of the magnetostrictive materials 16 along a length of the multimode preform 22.
  • the stacked magnetostrictive materials 16 and the packing rods 24 around the multimode preform 22 are held in position using a special jig and polytetrafluoroethylene (PTFE) tape.
  • PTFE polytetrafluoroethylene
  • Each of the plurality of magnetostrictive materials 16 stacked around the multimode preform 22 is disposed in a silica tube jacket 26 to prevent the melted magnetostrictive material 16 from diffusing into the fiber structure.
  • the precursor fiber 20 is heated at a temperature exceeding the melting point of the magnetostrictive material 16, as in block 104.
  • the heated precursor fiber 20 is first drawn to form an optical fiber cane with an outer diameter of approximately 2.5mm while continuously applying vacuum to the top of the precursor fiber 20, which is shown in block 106.
  • the application of vacuum to the top of the precursor fiber 20 during fabrication completely compresses and closes the interstitial holes between the silica cladding layer, and also to fixes the magnetostrictive material wire 16 in the silica tube jacket 26.
  • the application of vacuum helps to fill the packing rods 24 into the voids during fabrication of the optical fiber sensor 10 from the precursor fiber 20.
  • the optical fiber cane is further drawn to an outer diameter of around 125pm to form the optical fiber sensor 10.
  • the two-stage drawing helps to prevent structural defects in the optical fiber during the fabrication of the optical fiber sensor 10 which can be used for measuring distributed electromagnetic signals along the length of the fiber. Furthermore, the two-stage drawing during the fabrication of the optical fiber sensor 10 helps in the inspection of the cross-sections of the optical fiber cane samples to ensure formation of the optical fiber sensor 10 with uniform structure.
  • the plurality of magnetostrictive materials 16 disposed in the precursor fiber 20 include nickel wires which has a melting point of 1400°C and are placed in the silica tube jackets 26 disposed around the multimode preform 22, parallel to and around the core 12.
  • the silica material in the precursor fiber 20 has a melting point of 2100°C.
  • the optical fiber sensor 10 helps in the fabrication of the optical fiber sensor 10 from the precursor fiber 20 which is heated at temperatures exceeding 1400°C, at which the nickel wires melt fills within the silica tube jackets 26. Additional nickel wires are fed into the silica tube jackets 26 while continuously applying vacuum to the top of the precursor fiber 20 to completely compress and close the interstitial holes between the silica, and also to fix the nickel wires in the silica tube jackets 26.
  • the optical fiber sensor 10 thus formed for measuring distributed electromagnetic signals is a single optical fiber with standard optical fiber size of around 125pm in diameter.
  • FIGs 3(a)-(c) there is illustrated schematic views of melt filling of the magnetostrictive materials 16 into the silica tube jackets 26 provided around the multimode preform 22 of the precursor fiber 20 while continuously applying vacuum to the top of the precursor fiber 20 according to an embodiment of the invention.
  • pure silica tubes having 17-25mm diameter are drawn to form the multimode preform 22 having an approximate diameter of 10 mm having a central core 12 of the multimode preform 22 with an approximate diameter of 1.6 mm.
  • a number of magnetostrictive materials 16, each having diameter of around 1 mm inserted within the silica tube jackets 26 are disposed around the multimode preform 22, symmetrical and parallel to the core 12, as illustrated in Figure 3(a).
  • the precursor fiber 20 with the magnetostrictive materials 16 is heated at temperatures above the melting point of the magnetostrictive materials 16 to melt fill the nickel magnetostrictive materials 16 in the silica tube jackets 26.
  • additional magnetostrictive material 16 wires are continuously force filled into the silica tube jackets 26 as the magnetostrictive material 16 wires gets melted while continuously applying vacuum to the top of the precursor fiber 20, which further prevents the formation of air gaps between the silica and the magnetostrictive materials 16.
  • the vacuum also helps to fix the magnetostrictive materials 16 in the silica tube jackets 26 and completely fills the silica tube jackets 26 as illustrated in Figure 3(c).
  • the plurality of magnetostrictive materials 16 disposed in the cladding layer 14 parallel to and around the core 12 can be of cylindrical or polygonal shape and extends along the complete length of the fiber. Magnetization of the optical fiber causes expansion or contraction of the magnetostrictive materials 16 causing intensified strain on the fiber resulting in frequency shift in Rayleigh backscattered signal through the core 12. The frequency shift is measured to determine the electromagnetic signal strength anywhere along the length of the fiber.
  • the present invention may also include further additional modifications made to the magnetostrictive materials 16 to improve sensitivity which does not affect the overall functioning of the fiber or method.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Optical Transform (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un capteur à fibre optique (10) pour mesurer des signaux électromagnétiques comprenant un noyau (12) pour guider des signaux optiques le long d'une longueur du noyau (12) et une couche de gainage (14) comprenant une pluralité de matériaux magnétostrictifs (16) disposés parallèlement au noyau (12) et autour de celui-ci. La pluralité de matériaux magnétostrictifs (16) disposés parallèlement au noyau (12) et autour de celui-ci induisent magnétiquement une contrainte lors de l'expansion ou de la contraction des matériaux magnétostrictifs (16) provoquant un décalage de fréquence dans le signal rétrodiffusé de Rayleigh à travers le noyau (12). Le décalage de fréquence dans le signal rétrodiffusé de Rayleigh est mesuré pour déterminer l'intensité des signaux électromagnétiques sur la longueur de la fibre optique.
PCT/MY2021/050017 2020-03-19 2021-03-19 Capteur électromagnétique distribué à base de fibre optique et son procédé de fabrication WO2021187972A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MYUI2020001513 2020-03-19
MYUI2020001513 2020-03-19

Publications (1)

Publication Number Publication Date
WO2021187972A1 true WO2021187972A1 (fr) 2021-09-23

Family

ID=77771791

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/MY2021/050017 WO2021187972A1 (fr) 2020-03-19 2021-03-19 Capteur électromagnétique distribué à base de fibre optique et son procédé de fabrication

Country Status (1)

Country Link
WO (1) WO2021187972A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5627921A (en) * 1993-10-14 1997-05-06 Telefonaktiebolaget Lm Ericsson Optical fiber for sensors including holes in cladding
US20120086443A1 (en) * 2010-10-08 2012-04-12 Bazzone Michael L Generator Operation Monitoring
US9459329B2 (en) * 2010-09-01 2016-10-04 Optasense Holdings Limited Magnetic field detector
WO2019036706A1 (fr) * 2017-08-18 2019-02-21 Corning Incorporated Guides d'ondes optiques térahertz à base de verre et leurs procédés de formation
US11002594B2 (en) * 2015-11-20 2021-05-11 Sentek Instrument, Llc Method and apparatus for distributed sensing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5627921A (en) * 1993-10-14 1997-05-06 Telefonaktiebolaget Lm Ericsson Optical fiber for sensors including holes in cladding
US9459329B2 (en) * 2010-09-01 2016-10-04 Optasense Holdings Limited Magnetic field detector
US20120086443A1 (en) * 2010-10-08 2012-04-12 Bazzone Michael L Generator Operation Monitoring
US11002594B2 (en) * 2015-11-20 2021-05-11 Sentek Instrument, Llc Method and apparatus for distributed sensing
WO2019036706A1 (fr) * 2017-08-18 2019-02-21 Corning Incorporated Guides d'ondes optiques térahertz à base de verre et leurs procédés de formation

Similar Documents

Publication Publication Date Title
CA2964508C (fr) Methode et systeme de detection de temperature de reseau
US11320291B2 (en) Multi-parameter distributed fiber optic sensor system and methods of sensor manufacturing
US4151747A (en) Monitoring arrangement utilizing fiber optics
FI71842B (fi) Fiberoptisk spaenningssensor
US5627921A (en) Optical fiber for sensors including holes in cladding
US10712149B2 (en) Fiber optic cable for measuring pressure, temperature, and strain distributions
GB2401940A (en) Fibre optical cable for monitoring temperature and strain
Zhou et al. An optical fiber sensor based on lateral-offset spliced seven-core fiber for bending and stretching strain measurement
US10612947B2 (en) Distributed pressure, temperature, strain sensing cable using metal wires with slot grooves and optical fibers in the slot grooves
CN101738269A (zh) 一种光纤布拉格光栅温度传感器封装方法
US9770862B2 (en) Method of making adhesion between an optical waveguide structure and thermoplastic polymers
CN213398986U (zh) 一种通信和传感全能光缆
CN112833928B (zh) 级联宏弯曲和交替单模-多模光纤结构温度折射率传感器
WO2021187972A1 (fr) Capteur électromagnétique distribué à base de fibre optique et son procédé de fabrication
Rajinikumar et al. Design parameter evaluation of a metal recoated fiber Bragg grating sensors for measurement of cryogenic temperature or stress in superconducting devices
CN207147663U (zh) 一种极端环境下多点测量的光纤光栅温度传感器
Yan et al. Fabrication and experiment of a FBG strain sensor in high temperature environment
CN113640930B (zh) 一种opgw光缆传感光纤光单元及其制作方法和光缆
CN107290076B (zh) 一种极端环境下多点测量的光纤光栅温度传感器
CN109668652A (zh) 一种玻璃管填充的光纤温度测量装置
US20230160765A1 (en) Optical fiber pressure sensor and method of sensing thereof
CN112729377B (zh) 粗锥干涉结构、制备方法及温度浓度双参数测量方法
JPH11144937A (ja) 荷重支持体
WO2023118859A1 (fr) Capteur optique
CN117090064A (zh) 一种光栅智慧预应力钢绞线及其制作方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21772483

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205 DATED 15/02/2024)