WO2018048326A1 - Capteur à fibre optique à répartition allongé - Google Patents

Capteur à fibre optique à répartition allongé Download PDF

Info

Publication number
WO2018048326A1
WO2018048326A1 PCT/RU2017/000620 RU2017000620W WO2018048326A1 WO 2018048326 A1 WO2018048326 A1 WO 2018048326A1 RU 2017000620 W RU2017000620 W RU 2017000620W WO 2018048326 A1 WO2018048326 A1 WO 2018048326A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
radiation
sensitive
optical fiber
source
Prior art date
Application number
PCT/RU2017/000620
Other languages
English (en)
Russian (ru)
Inventor
Владимир Николаевич БУРОВ
Вячеслав Владимирович СЕМЕНЮГА
Яна Владимировна ЗЕНКИНА
Дмитрий Борисович ЗАХАРОВ
Вячеслав Иванович ПЕРЕДЕРИЙ
Вадим Анатольевич ЯКОВЛЕВ
Original Assignee
Общество с ограниченной ответственностью "ТСТ Инжиниринг"
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 Общество с ограниченной ответственностью "ТСТ Инжиниринг" filed Critical Общество с ограниченной ответственностью "ТСТ Инжиниринг"
Priority to DE212017000210.7U priority Critical patent/DE212017000210U1/de
Publication of WO2018048326A1 publication Critical patent/WO2018048326A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
    • G01B11/18—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge using photoelastic elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection
    • G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
    • G01D5/35364—Sensor working in reflection using backscattering to detect the measured quantity using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering

Definitions

  • the utility model relates to distributed fiber-optic sensors based on the Brillouin light scattering phenomenon, using optical fiber as a sensitive element and can be used to measure the distribution of mechanical stresses and / or temperature with high accuracy and high spatial resolution.
  • Fiber optic sensors are known for measuring the distribution of physical quantities, such as temperature, strain and hydrostatic pressure along a sensitive optical fiber, which use methods based on recording the distribution of the fine structure parameters of scattered radiation, namely Brillouin scattering, also called Mandelstam-Brillouin scattering.
  • the location at which the physical parameter is measured is based on recalculating the delay time from sensing to recording the scattering signal to a distance that corresponds to the path of light radiation along the optical fiber from the analyzer to the scattering point and vice versa.
  • the delay time can be measured directly, as, for example, in the well-known fiber-optic Brillouin analyzer (RF patent for utility model 140707, published on 05.20.2014).
  • the well-known analyzer uses the Brillouin optical analysis method in the time representation (BOTDA, Brillouin Optical Time Domain Analysis), which uses the principles of optical reflectometry in the time representation (OTDR, Optical Time Domain Reflectometry).
  • BOTDA Brillouin Optical Time Domain Analysis
  • OTDR Optical Time Domain Reflectometry
  • the delay time is measured between the optical radiation pulse participating in Brillouin scattering and the signal detected by the photodetector, attributed to the Brillouin scattering phenomenon, which propagates in the optical fiber in the opposite direction to the pulse.
  • Brillouin scattering in an optical fiber can be considered as diffraction of light by a moving refractive index grating created by an acoustic wave.
  • the signal reflected from the grating experiences a Doppler frequency shift, since the grating moves with the speed of sound.
  • the speed of sound is directly related to the density of the material and depends both on its temperature and on internal mechanical stress (deformation).
  • the magnitude of the Brillouin frequency shift carries information about the temperature and strain at the scattering point.
  • Accurate determination of the strain requires temperature measurement and subtraction of the temperature contribution to the Brillouin frequency shift, i.e., thermal compensation.
  • the Brillouin shift depends solely on temperature.
  • the measurement of the Brillouin frequency shift allows the measurement of temperature and strain.
  • the closest technical solution is a well-known distributed fiber optic sensor for measuring strain and / or temperature (see RF Patent N ° 2346235, published July 27, 2008), which uses a method based on the Brillouin scattering phenomenon.
  • the known sensor comprises a source of stepwise optical light (optical) radiation for generating an optical pulse having a stepwise distribution of light intensity increasing toward the center, and a source of continuous light radiation for generating continuous light radiation.
  • the sensor also contains a sensitive optical fiber onto which an optical pulse is incident as the sounding light of the sensing, and the continuous light is incident as the light of the pump, so as to cause the Brillouin scattering between the light of the sounding and the light of the pump, and a Brillouin scattering detector in the time domain for determining the Brillouin attenuation spectrum or the Brillouin gain spectrum from light radiation, the output arising from a sensitive optical fiber and the attributed phenomenon of Brillouin scattering.
  • the measurement of the strain caused inside the sensitive optical fiber and / or the temperature of the sensitive optical fiber is made on the basis of a certain Brillouin attenuation spectrum or Brillouin gain spectrum.
  • a disadvantage of the known sensor is that it does not allow to limit the portion of the optical fiber where the Brillouin scattering phenomenon occurs, so that a signal attributed to the Brillouin scattering phenomenon that occurs throughout the sensitive optical fiber, which leads to an increase in the measurement time, is incident on the detector. signal-to-noise ratio and limits the distance from light sources and the detector to the most remote portion of the sensitive optical wave window.
  • the problem solved by the claimed sensor is the improvement of technical and operational characteristics and the provision of the possibility of measurements at a sufficiently large distance from demanding conditions placement of sensor components - optical radiation sources and detector.
  • the technical result that was obtained by performing the claimed sensor was an increase in the distance from the sources of optical radiation and the detector to the most remote portion of the sensitive optical fiber, a decrease in the measurement duration, and an increase in the signal-to-noise ratio.
  • the distributed fiber-optic sensor for measuring strain and / or temperature using the Brillouin scattering phenomenon comprising a source of first optical radiation, a source of second optical radiation, a sensitive optical fiber and an optical radiation detector, the first end of the sensitive the optical fiber is connected to the source of the first optical radiation, the second end of the sensitive optical fiber is connected to the source the eyelid of the second optical radiation, in order to thereby cause the Brillouin scattering phenomenon between the first and second optical radiations, and the detector is connected to the first end of the sensitive optical fiber for detecting radiation coming out of the sensitive optical fiber and attributed to the Brillouin scattering phenomenon, it is equipped with a linear path of the optical fiber line transmission, through which the source of the second optical radiation is connected to a sensitive optical fiber, eynogo tract is at least half the length of the sensing optical fiber line path and is equipped with a device to prevent it from entering the optical radiation from sensitive optical fiber.
  • a device that prevents optical radiation from entering a sensitive optical fiber into the linear path can be made in the form of an optical insulator.
  • connection of the sensitive optical fiber to the source of the first optical radiation and the detector can be performed by means of an optical circulator.
  • Deformation and / or temperature can be measured based on a specific Brillouin attenuation spectrum.
  • the strain and / or temperature can be measured based on a specific Brillouin gain spectrum.
  • the source of the first optical radiation, the source of the second optical radiation and the detector of optical radiation can be located in a common housing.
  • FIG. 1 depicts a generalized functional diagram of the claimed distributed fiber optic sensor for measuring strain and / or temperature using the Brillouin scattering phenomenon.
  • the distributed fiber-optic sensor (Fig. 1) for measuring strain and / or temperature using the Brillouin scattering phenomenon comprises a first optical radiation source 1, a second optical radiation source 2, a sensitive optical fiber 3 and an optical radiation detector 4.
  • the first end of the sensitive optical fiber 3 is connected to a source 1 of the first optical radiation and an optical radiation detector 4.
  • the connection can be made using an optical circulator 5.
  • the second optical radiation source 2 is connected to the second end of the sensitive optical fiber 3 through a linear path 6 of the optical fiber transmission line, the length of which is at least half the length of the sensitive optical fiber.
  • the linear path 6 is equipped with a device 7 that prevents optical radiation from entering into it from a sensitive optical fiber 3.
  • a device 7 that prevents optical radiation from entering a linear path from a sensitive optical fiber can be made in the form of an optical insulator.
  • the source 1 of the first optical radiation, the source 2 of the second optical radiation and the detector 4 of the optical radiation can be located in a common housing 8, for example, in the same way as in the prior art distributed fiber optic sensors.
  • the distributed fiber optic sensor (Fig. 1) operates as follows.
  • the source 1 emits a first optical radiation that enters and propagates into the sensitive optical fiber 3.
  • the source 2 emits a second optical radiation, which through the linear path 6 of the fiber optic transmission line and the insulator 7 will fall into the sensitive optical fiber 3 and propagates in it towards the first optical radiation.
  • the linear path 6 provides the transmission of the second optical radiation with the desired characteristics without distortion.
  • Source 1 and source 2 have characteristics that ensure their applicability to the corresponding Brillouin optical analysis method.
  • a Brillouin scattering phenomenon occurs between the first and second optical radiations, which generates a signal attributed to the Brillouin scattering phenomenon, which propagates through the sensitive optical fiber 3 and enters the detector 4.
  • Connecting the sensitive optical fiber 3 to the source 1 of the first optical radiation and the detector 4 can be performed by means of an optical circulator 5.
  • the circulator 5 directs the first optical radiation from and point 1 into the sensitive optical fiber 3, and the radiation from the sensitive optical fiber 3 to the detector 4.
  • the use of the circulator 5 prevents the first optical radiation from parasitically entering the detector 4, and also prevents the radiation from the sensitive optical fiber 3 from reaching the source 1.
  • Using the circulator 5 also provides the transmission of radiation from a sensitive optical fiber 3 to the detector 4 with low loss.
  • Optical circulators are standard components and are commercially available (see, for example, URL: https://www.thorlabs.com/newgrouppage9.cfm7obiectgroup id— 373, accessed 05/13/2016).
  • Detector 4 measures the Brillouin attenuation spectrum or the Brillouin gain spectrum from optical radiation emerging from the sensitive optical fiber 3 and attributed to the Brillouin scattering phenomenon, and determines the deformation and / or temperature of the sensitive optical fiber 3 based on a specific Brillouin attenuation spectrum or the Brillouin amplification spectrum.
  • the spatial distribution of the measured value along the sensitive optical fiber is determined by methods known from the prior art.
  • the Brillouin optical analysis method in time representation BOTDA
  • the optical radiation detector detects radiation emerging from the sensitive optical fiber and attributed to the Brillouin scattering phenomenon depending on the delay time relative to the pulse of the first optical radiation .
  • the distance to the measurement point is calculated based on the conversion of the corresponding delay time.
  • sources 1, 2 and detector 4 can be performed in the same way as in the closest technical solution (prototype).
  • the inventive sensor can also use the Brillouin optical analysis method in the frequency representation (BOFDA), when the first optical radiation is harmonically modulated in amplitude and the optical radiation detector detects the phase and amplitude of the radiation emerging from the sensitive optical fiber and attributed to the Brillouin scattering phenomenon, depending on the frequency modulation of the first optical radiation.
  • sources 1, 2 and detector 4 can be performed in the same way as in the commercially available system based on the Brillouin light scattering phenomenon (see URL: http://www.fibristerre.de/products-and -services /, accessed 05/13/2016).
  • Fiber optic transmission lines are widely used to transmit and receive an optical signal.
  • Fiber-optic transmission line is a combination of linear paths of fiber-optic transmission systems having a common optical cable, linear structures and devices for their maintenance within the limits of action service devices.
  • Mandatory channel-forming elements of a fiber optic transmission line are optical fibers.
  • Optical fibers are characterized by the attenuation parameter of the optical signal and dispersion characteristics. Typical attenuation of radiation with a wavelength of 1550 nm in a single-mode coupled optical fiber is 0.19-0.22 dB / km and the chromatic dispersion is about 20 ps / (nm km).
  • the amplitude of the optical signal decreases due to attenuation, and the temporal shape of the signal may be distorted due to the contribution of chromatic dispersion.
  • optical amplifiers widely used in the communications industry can be used, for example, Erbium or Raman amplifiers, which are installed at a certain distance so that the gain compensates for the total attenuation and loss of optical power in the previous section.
  • a typical length of a linear path section without amplifiers is 50 km, which corresponds to a 10 dB loss in optical signal power.
  • spectral optical filters can be used in the linear path 6, which filter the optical useful signal from the spectral noise of optical amplifiers, for example, from spontaneous emission of an Erbium amplifier, by the wavelength spectrum.
  • dispersion compensators fiber or semiconductor
  • the use of optical fibers supporting the state of polarization of the signal allows one to get rid of the polarization-mode dispersion and reduce distortion in the transmission line.
  • the combination of an optical amplifier with a dispersion compensator sequentially installed behind it in the linear path is a repeater, the use of which allows you to restore the shape of the signal transmitted along the linear path 6 to the original state, that is, repeat the signal.
  • the device 7 can be made in the form of an optical isolator.
  • Optical isolators are standard components and commercially available (see, for example, URL: https://www.go4fiber.com/laboratorv-and- component / isolator, accessed 05/13/2016).
  • the device 7 prevents the first optical radiation from entering the linear path 6 of the fiber-optic transmission line, preventing unwanted non-linear interactions (in particular, the Brillouin scattering phenomenon) of the first optical radiation and the second optical radiation, which can lead to a change in the amplitude and phase of the first optical radiation in linear tract 6 of a fiber optic transmission line.
  • the device 7 limits the region where the Brillouin scattering phenomenon occurs to the sensitive optical fiber 3.
  • the length of the linear path 6 of the optical fiber transmission line is chosen to be at least half the length of the sensitive optical fiber 3. Denote the length of the sensitive optical fiber 3 by L.
  • L / 2 half the length of the sensitive optical fiber 3
  • a reduction in the measurement duration is achieved for sensors when it is necessary to make measurements at a distance from the optical radiation sources 1, 2 and detector 4 due to the fact that the Brillouin scattering phenomenon does not occur in the linear path 6, so that the fiber section analyzed by optical reflectometry is reduced to sensitive optical fiber 3, which reduces the measurement time in accordance with a decrease in the propagation time of optical radiation from source 1 through a sensitive optical fiber Well, 3 to device 7 and back to detector 4.
  • the typical maximum permissible length of the sensitive optical fiber does not exceed 50 km, so that the length of the linear path 6 of the optical fiber transmission line is not less than half the length of the sensitive optical fiber 3 is easily implemented using standard solutions in the communications industry.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

Ce capteur relève du domaine des capteurs à fibre optique à répartition qui sont à l'origine de la diffusion de Brillouin de la lumière et que l'on utilise en qualité d'élément sensible de fibre optique, et peut être utilisé pour mesurer la distribution d'une tension mécanique et/ou de la température avec une grande précision et une résolution spatiale élevée. Ce capteur à fibre optique à répartition pour mesurer la déformation et/ou la température dans le cadre de la diffusion de Brillouin comprend deux sources de rayonnement optique, une fibre optique sensible et un détecteur de rayonnement optique; la première extrémité de la fibre optique sensible est connectée à la première source et la seconde extrémité à la seconde source. Le détecteur est connecté à la première extrémité de la fibre optique sensible pour enregistrer un signal. La seconde source est connectée à la fibre optique sensible par une piste linéaire d'une ligne de transmission à fibre optique dont la longueur représente au moins la moitié de la longueur de la fibre optique sensible, la piste linéaire comportant également un dispositif empêchant la pénétration dans celle-ci du rayonnement optique depuis la la fibre optique sensible. Le résultat technique consiste en une plus grande distance jusqu'aux sections à mesurer éloignées, en une diminution de la durée de mesure, et en une amélioration du rapport signal/bruit.
PCT/RU2017/000620 2016-09-06 2017-08-25 Capteur à fibre optique à répartition allongé WO2018048326A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE212017000210.7U DE212017000210U1 (de) 2016-09-06 2017-08-25 Verteilter gestreckter faseroptischer Sensor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RU2016135836 2016-09-06
RU2016135836 2016-09-06

Publications (1)

Publication Number Publication Date
WO2018048326A1 true WO2018048326A1 (fr) 2018-03-15

Family

ID=61562777

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/RU2017/000620 WO2018048326A1 (fr) 2016-09-06 2017-08-25 Capteur à fibre optique à répartition allongé

Country Status (2)

Country Link
DE (1) DE212017000210U1 (fr)
WO (1) WO2018048326A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2735910C1 (ru) * 2020-02-07 2020-11-10 Открытое акционерное общество Всероссийский научно-исследовательский, проектно-конструкторский и технологический институт кабельной промышленности (ВНИИ КП) Способ определения срока сохраняемости оптического кабеля

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2485454C2 (ru) * 2011-06-24 2013-06-20 Общество с ограниченной ответственностью "Инновационное предприятие "НЦВО-ФОТОНИКА" (ООО ИП "НЦВО-Фотоника") Распределенная волоконно-оптическая система регистрации виброакустических сигналов
RU136660U1 (ru) * 2013-07-18 2014-01-10 Андрей Андреевич Катанович Оптический рефлектометр
US8699009B2 (en) * 2008-11-27 2014-04-15 Neubrex Co., Ltd. Distributed optical fiber sensor
WO2015170355A1 (fr) * 2014-05-05 2015-11-12 Filippo Bastianini Appareil d'interrogation de capteurs répartis à fibre optique faisant appel à un interféromètre dans le domaine fréquentiel optique à diffusion brillouin stimulée

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008019150B4 (de) 2008-04-16 2010-07-08 BAM Bundesanstalt für Materialforschung und -prüfung Vorrichtung und Verfahren zur Brillouin-Frequenzbereichsanalyse
RU140707U1 (ru) 2012-02-02 2014-05-20 Общество с ограниченной ответственностью "ПетроФайбер" Волоконно-оптический бриллюэновский анализатор

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8699009B2 (en) * 2008-11-27 2014-04-15 Neubrex Co., Ltd. Distributed optical fiber sensor
RU2485454C2 (ru) * 2011-06-24 2013-06-20 Общество с ограниченной ответственностью "Инновационное предприятие "НЦВО-ФОТОНИКА" (ООО ИП "НЦВО-Фотоника") Распределенная волоконно-оптическая система регистрации виброакустических сигналов
RU136660U1 (ru) * 2013-07-18 2014-01-10 Андрей Андреевич Катанович Оптический рефлектометр
WO2015170355A1 (fr) * 2014-05-05 2015-11-12 Filippo Bastianini Appareil d'interrogation de capteurs répartis à fibre optique faisant appel à un interféromètre dans le domaine fréquentiel optique à diffusion brillouin stimulée

Also Published As

Publication number Publication date
DE212017000210U1 (de) 2019-04-15

Similar Documents

Publication Publication Date Title
EP2183624B1 (fr) Système de détection réparti par fibre optique
AU2018343339B2 (en) Tailor distributed amplification for fiber sensing
US9599460B2 (en) Hybrid Raman and Brillouin scattering in few-mode fibers
CA2563597C (fr) Mesure directe de frequence brillouin dans des systemes de detection optiques repartis
EP1338876A2 (fr) Réflectrométrie optique temporelle
CN102639966A (zh) 光学传感器及使用方法
US8734011B2 (en) Distributed optical fiber temperature sensor based on optical fiber delay
KR101633954B1 (ko) 광섬유의 다이내믹 레인지를 향상시키고 측정 불확실성을 감소시키기 위한 시스템
KR101310783B1 (ko) 브릴루앙 이득 및 손실 동시 측정을 이용한 분포형 광섬유 센서 및 센싱 방법
Uyar et al. A direct detection fiber optic distributed acoustic sensor with a mean SNR of 7.3 dB at 102.7 km
US7693358B2 (en) Fiber optic distributed sensor apparatus
WO2018048326A1 (fr) Capteur à fibre optique à répartition allongé
Yang et al. Thousands of fiber grating sensor array based on draw tower: a new platform for fiber-optic sensing
WO2018048327A1 (fr) Capteur à fibre optique distribué
RU170925U1 (ru) Протяженный распределенный волоконно-оптический датчик
RU170943U1 (ru) Распределенный волоконно-оптический датчик
CN113091783B (zh) 基于二级布里渊散射的高灵敏传感装置及方法
CN113670353B (zh) 一种基于少模光纤模式复用的布里渊光时域分析仪
CN113670354B (zh) 基于少模光纤模式复用的布里渊光时域反射仪
Sandah et al. Spectral Shadowing Compensation in Double-pulse FBG-assisted φ-OTDR
RU186277U1 (ru) Оптический бриллюэновский рефлектометр для систем мониторинга оптических волокон
KR102644918B1 (ko) 감도 향상형 광섬유 음향 분포센서
Allousch et al. Extended range of repeaterless distributed acoustic sensing with coherent OTDR interrogators utilising optical amplification
Brown et al. Combined Raman and Brillouin scattering sensor for simultaneous high-resolution measurement of temperature and strain
RU2550768C1 (ru) Устройство для мониторинга виброакустической характеристики протяженного объекта

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: 17849190

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17849190

Country of ref document: EP

Kind code of ref document: A1