An armored DSS cable includes: an inner layer part including a first rope helically wound; and a surface layer part including an optical fiber module and a plurality of third ropes, the optical fiber module having an optical fiber and a plurality of second ropes helically surrounding the optical fiber and having a smaller outer diameter than the first rope, the third ropes having a larger outer diameter than the first rope, such that the optical fiber module and the third ropes are arranged on an identical circle and helically wound, wherein the inner layer part and the surface layer part are formed concentrically.
A fiber optic cable includes a braided core defining a plurality of helical grooves, and one or more optical fibers disposed along one or more of the helical grooves of the braided core. The elongated structures braided to form the braided core are composed of braided ropes or monolithic wires. An outer layer disposed over an outer surface of the braided core is composed of a metal layer or a flexible plastic layer.
NISHI NIPPON ELECTRIC WIRE & CABLE CO., LTD. (Japan)
Inventor
Kishida, Kinzo
Yamauchi, Yoshiaki
Kawabata, Junichi
Seno, Shoji
Nagatani, Hideki
Imai, Michio
Hamada, Yukihiro
Watanabe, Kazumitu
Abstract
A distributed position detection rope includes: basic optical elements each including an optical fiber, tensile strength bodies, and a sheath material and the tensile strength bodies; a cylindrical inner sheath layer having a first optical element formed by arranging a plurality of the basic optical elements which are arranged at positions on the same circle and are helically wound at a predetermined pitch along the axial direction of the axis; and a cylindrical outer sheath layer on the outer side of the inner sheath layer and having a second optical element which are arranged at positions on the same circle and are helically wound along the axial direction so as to have a placement angle different from that of the basic optical elements of the first optical element.
G01D 5/353 - 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 using optical 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
4.
Method and system for detecting and identifying vibration on basis of optical fiber signal feature to determine time-space
A method for detecting and specifying a vibration on the basis of a feature of a fiber-optic signal to determine a time and a spatial location of the present invention includes: Step 1 of acquiring a feature-expanded function vector and C-number of vibration categories by expanding a feature of initial data of a vibration signal from a distributed fiber-optic sensor; Step 2 of calculating a dimensionality reduction matrix based on the feature-expanded function vector; Step 3 of acquiring a dimensionality-reduced feature function by operating the dimensionality reduction matrix to the initial data and the feature-expanded function vector; Step 4 of acquiring a primary classification result of the vibration signal by performing a classification with reference to primary classification parameter acquired from a parameter database; and Step 5 of acquiring and outputting a secondary classification result of the vibration signal by performing removal of a wrong detection result and correction of a wrong classification result of the primary classification result.
G01H 9/00 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
G06N 20/10 - Machine learning using kernel methods, e.g. support vector machines [SVM]
G06F 18/22 - Matching criteria, e.g. proximity measures
G06F 18/214 - Generating training patterns; Bootstrap methods, e.g. bagging or boosting
G06F 18/2135 - Feature extraction, e.g. by transforming the feature space; Summarisation; Mappings, e.g. subspace methods based on approximation criteria, e.g. principal component analysis
G06F 18/2413 - Classification techniques relating to the classification model, e.g. parametric or non-parametric approaches based on distances to training or reference patterns
G06F 18/243 - Classification techniques relating to the number of classes
An oil well production method in which a plurality of producers are arranged in a horizontal direction, includes boring a monitor well adjacent to one of the producers in the horizontal direction, installing a measurement optical fiber cable in the monitor well, performing Brillouin measurement and Rayleigh measurement for a strain distribution, a pressure distribution, and a temperature distribution of the monitor well along the measurement optical fiber cable over a period in which a fracture occurs hydraulically in the producers and an oil producing period, analyzing data measured through the Brillouin measurement and the Rayleigh measurement, and determining an arrangement interval of the producers in the horizontal direction and a hydraulic fracturing parameter.
E21B 43/30 - Specific pattern of wells, e.g. optimizing the spacing of wells
E21B 49/00 - Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
G01V 1/22 - Transmitting seismic signals to recording or processing apparatus
G01V 1/42 - Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators in one well and receivers elsewhere or vice-versa
E21B 43/267 - Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
A monitoring humidity measurement system includes: a humidity measurement optical fiber including a first optical fiber and a humidity detection layer provided so as to annularly cover the first optical fiber; a reference optical fiber including a second optical fiber; a plurality of optical communication cables; and a signal processing device configured to, with a laser beam entering into the first and second optical fibers, calculate and obtain Brillouin frequency shift and Rayleigh frequency shift of backscatter light from the first and second optical fibers based on the entering laser beam, and store predetermined constants, wherein reference data and target data are measured from the Rayleigh frequency shift and an initial humidity value calculated from the Brillouin frequency shift, and the value of humidity at the present time is calculated on the basis of Rayleigh frequency shift per unit humidity calculated from a difference between the above two data.
G01D 5/353 - 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 using optical 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
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01K 11/322 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres using Brillouin scattering
7.
Distributed fibre sensing system and vibration detection and positioning method therefor
A distributed fibre sensing system and a vibration detection and positioning method therefor are disclosed. The system comprises: a signal generating module, a light source module, an optical frequency comb generating module, a frequency sweeping and pulse generating module, an optical circulator, a sensing fibre, an interference module, a photoelectric conversion module and a detection and position module. The method comprises: obtaining a plurality of Rayleigh backscattering signals of the sensing fibre; performing a fading elimination processing on the Rayleigh backscattering signals, thereby obtaining a plurality of averaged Rayleigh backscattering signals of non-interference fading and polarization fading; performing a phase processing on the averaged Rayleigh backscattering signals, thereby obtaining phase variance curves; and determining a vibration point according to variances in the phase variance curves, and finally obtaining a position and a vibration waveform of the vibration point.
G01H 9/00 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
G01D 5/353 - 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 using optical 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
8.
Brillouin scattering measurement method and Brillouin scattering measurement device
In a measurement requiring a high space resolution using S-BOTDR, a pulse train composed of a plurality of pulses having the interval between the pulses longer than the phonon lifetime is interpulse-code-modulated. A Golay code is used for the interpulse code modulation to eliminate the sidelobes of the correlation in using a technique of correlation. In a technique without using correlation, an Hadamard matrix is used for the interpulse code modulation and the resultant matrix is inverted in the signal processing.
G01N 21/63 - Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01D 5/353 - 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 using optical 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
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01K 11/322 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres using Brillouin scattering
9.
Fiber optic cable for measuring pressure, temperature, and strain distributions
A DPTSS fiber optic cable includes an optical fiber sheathing cylindrical metal tube accommodating a pressure sensor optical fiber and having a plurality of through holes formed therein; and pressure blocking sections formed at intervals in the axial direction of the cable.
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01D 5/353 - 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 using optical 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
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
G01L 11/02 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group or by optical means
G02B 6/44 - Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
10.
Rayleigh measurement system and Rayleigh measurement method
Initial data and target data are frequency-analyzed to obtain an initial Rayleigh-scattering spectrum (RSS) and a target RSS, respectively. A distance correction is performed for the target RSS by comparing the target RSS with the initial RSS, and a Rayleigh spectrum shift is determined on the basis of a correlation coefficient between the initial RSS and the target RSS after distance-corrected.
G01D 5/353 - 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 using optical 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
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
11.
Frequency synthesis-based optical frequency domain reflectometry method and system
Frequency synthesis-based optical frequency domain reflectometry method and system are disclosed. The method is to implement optical frequency reflectometry and comprises: performing an electro-optic modulation and an acousto-optic modulation on a local light to obtain an optical pulse; inputting the optical pulse as a detection pulse optical signal to a test optical fiber; and detecting an obtained Rayleigh backscattered optical signal under coherent detection with the local light, and then performing a photoelectric conversion and a demodulation, wherein: the electro-optic modulation is performed by using a single frequency signal; the acousto-optic modulation is performed by using a pulse signal; and the optical pulse is obtained by simultaneously sweeping multiple frequency components of an optical comb signal which is obtained by the electro-optic modulation.
H04B 10/071 - Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
12.
Distributed pressure, temperature, strain sensing cable using metal wires with slot grooves and optical fibers in the slot grooves
A distributed pressure, temperature, strain (DPTS) sensing cable includes at least two slotted fiber optic metal wires each having a slot groove extended along in an outer circumference of the wires to encapsulate optical fibers in the slot grooves. The two slotted fiber optic metal wires have characteristics different from each other.
G01D 5/353 - 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 using optical 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
G02B 6/44 - Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
G01D 5/26 - 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 using optical means, i.e. using infrared, visible or ultraviolet light
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01H 9/00 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
G01V 1/00 - Seismology; Seismic or acoustic prospecting or detecting
G01V 1/42 - Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators in one well and receivers elsewhere or vice-versa
G01V 1/22 - Transmitting seismic signals to recording or processing apparatus
14.
Brillouin scattering measurement method and brillouin scattering measurement system
A Brillouin backscattered spectrum is obtained in such a way that two optical pulse pairs each composed of two pulses of different durations and of the same phase and Π phase difference are launched into a sensing optical fiber; Brillouin backscattered lights produced by the optical pulse pairs are detected into signals for the respective optical pulse pairs; the signals are sampled with two window functions whose time widths are equal to respective pulse durations of the optical pulse pair and whose delay time is variable; each sampled signal is transformed with a predetermined transformation; products of the transformed signals are calculated; and subtraction between the products is performed.
G01D 5/353 - 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 using optical 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
H01S 5/12 - Construction or shape of the optical resonator the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
A fiber optic biodiagnostic sensor system includes a blood vessel insertable pressure distribution measurement device to be inserted in vivo into a blood vessel to measure distributions of temperature and pressure of an object to be measured along a predetermined site, the device having an SM optical fiber deformable by temperature and strain, a structural member being in contact with a portion of the optical fiber to convert pressure of the to-be-measured object to strain of the optical fiber; and an outer layer converting the optical fiber and the structural member. The sensor system further includes a measurement unit emitting laser light into the SM optical fiber, detecting a frequency shift produced in the scattered light, and calculating a blood pressure at a given position of the optical fiber from a pressure change and a strain change of the SM optical fiber that are calculated from the frequency shift.
A61B 5/0215 - Measuring pressure in heart or blood vessels by means inserted into the body
A61B 5/1459 - Measuring characteristics of blood in vivo, e.g. gas concentration, pH-value using optical sensors, e.g. spectral photometrical oximeters invasive, e.g. introduced into the body by a catheter
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
G01D 5/353 - 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 using optical 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
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01K 13/00 - Thermometers specially adapted for specific purposes
A61B 5/00 - Measuring for diagnostic purposes ; Identification of persons
RESEARCH INSTITUTE OF INNOVATIVE TECHNOLOGY FOR THE EARTH (Japan)
NEUBREX CO., LTD. (Japan)
Inventor
Xue, Ziqiu
Kishida, Kinzo
Yamauchi, Yoshiaki
Suzaki, Shinzo
Abstract
In an optical fiber cable that includes an optical fiber core for measuring pressure and a multilayer armor cable for measuring temperature, an annular clearance space having a desired thickness is formed between the optical fiber core and the multilayer armor cable and fixing members for fixing the optical fiber core and the multilayer armor cable are provided at predetermined intervals in the axial direction of the optical fiber cable.
G02B 6/00 - Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
G01D 5/353 - 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 using optical 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
G02B 6/44 - Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
A plurality of optical fibers is helically embedded in tubular installation layers on the outer circumferential surface of a shaped body having a circular cross section. A three-dimensional position of the shaped body after deformed produced by bend, torsion, or stretch due to external force is measured by utilizing frequency change or phase change of pulse laser light emitted into the optical fibers caused by Brillouin scattering and/or Rayleigh scattering occurring in the optical fiber deformed in accordance with the shaped body deformation.
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01D 5/353 - 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 using optical 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
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
RESEARCH INSTITUTE OF INNOVATIVE TECHNOLOGY FOR TH (Japan)
NEUBREX CO., LTD. (Japan)
Inventor
Xue, Ziqiu
Yamauchi, Yoshiaki
Kishida, Kinzo
Abstract
Under a known pressure is externally applied to a reference member to which an optical fiber is fixed, test light is allowed to enter the optical fiber, and at least one of a reference Brillouin measurement for determining a reference Brillouin frequency shift amount based on the Brillouin scattering phenomenon, and a reference Rayleigh measurement for determining a reference Rayleigh frequency shift amount based on the Rayleigh scattering phenomenon is performed. A Brillouin measurement coefficient or a Rayleigh measurement coefficient is determined from these calculation results. An optical fiber is fixed to a sample member, the volumetric change of which is unknown, and the same sample Brillouin measurement or sample Rayleigh measurement is performed to determine the frequency shift amount. The volumetric change of the sample member is determined from the sample Brillouin or the sample Rayleigh frequency shift amount, and from the Brillouin or the Rayleigh measurement coefficient.
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01B 11/24 - Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
G01D 5/353 - 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 using optical 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
G01F 17/00 - Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies
G01D 18/00 - Testing or calibrating apparatus or arrangements provided for in groups
G01D 5/26 - 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 using optical means, i.e. using infrared, visible or ultraviolet light
G01V 8/16 - Detecting, e.g. by using light barriers using one transmitter and one receiver using optical fibres
G01B 21/04 - Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness by measuring coordinates of points
19.
Distribution measurement system for pressure, temperature, strain of material, monitoring method for carbon dioxide geological sequestration, assessing method for impact of carbon dioxide injection on integrity of strata, and monitoring method for freezing using same
RESEARCH INSTITUTE OF INNOVATIVE TECHNOLOGY FOR THE EARTH (Japan)
NEUBREX CO., LTD. (Japan)
Inventor
Xue, Ziqiu
Yamauchi, Yoshiaki
Kishida, Kinzo
Abstract
Distributions of a Brillouin frequency shift and a Rayleigh frequency shift in optical fibers set up in a material are measured from scattered waves of pulse laser light entered into the optical fibers, and distributions of pressure, temperature, and strain of the material along the optical fibers at a measurement time point are analyzed using coefficients that are inherent to the set up optical fibers and correlate pressure, temperature, and strain of material with the Brillouin frequency shift and the Rayleigh frequency shift.
G01N 21/00 - Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
G01D 5/353 - 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 using optical 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
B01J 19/00 - Chemical, physical or physico-chemical processes in general; Their relevant apparatus
G01K 11/12 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in colour, translucency or reflectance
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01K 11/32 - Measuring temperature based on physical or chemical changes not covered by group , , , or using changes in transmittance, scattering or luminescence in optical fibres
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
G01L 19/00 - MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE - Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
A distributed optical fiber sound wave detection device is provided with an optical pulse emission unit that causes an optical pulse to be incident into the optical fiber, and a Rayleigh scattered light reception unit that receives Rayleigh scattered light produced inside the optical fiber. The optical pulse emission unit outputs the optical pulse that is modulated using a code sequence which has a predetermined length and by which the optical pulse is divided into a plurality of cells. The Rayleigh scattered light reception unit includes a phase variation derivation unit that performs demodulation corresponding to the modulation in the optical pulse emission unit on the Rayleigh scattered light and determines a phase variation thereof from the demodulated Rayleigh scattered light, and a sound wave detection unit that determines a sound wave that has struck the optical fiber from the phase variation determined by the phase variation derivation unit.
H04B 10/08 - Equipment for monitoring, testing or fault measuring
H04B 10/071 - Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
G01H 9/00 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
The present invention provides a distributed optical fiber sensor capable of measuring the strain and temperature of an object to be measured simultaneously and independently with high spatial resolution. A distributed optical fiber sensor FS is a distributed optical fiber sensor which uses an optical fiber 15 as a sensor, and a strain and temperature detector 14 measures a Brillouin frequency shift amount caused by a strain and a temperature generated in the optical fiber 15 by using a Brillouin scattering phenomenon, measures a Rayleigh frequency shift amount caused by the strain and temperature generated in the optical fiber 15 by using a Rayleigh scattering phenomenon, and calculates the strain and temperature generated in the optical fiber 15 from the measured Brillouin frequency shift amount and Rayleigh frequency shift amount.
G01B 11/16 - Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
G01L 1/24 - Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis
A structure monitor system comprising a measuring unit 3 for measuring distortions of the structure S at respective points on a boundary by using an optical fiber sensor 2 laid on the boundary of the structure, numerical analysis unit 5 for calculating a distortion at a specified point on the structure S by a numerical analysis method with distortions measured by the measuring unit as a boundary condition, and a display unit 6 for displaying information on an analysis distortion by the numerical analysis unit 5 in a association with a position on the structure S.
G01B 5/30 - Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge
A distributed optical fiber sensor uses a Brillouin scattering phenomenon to avoid manual adjustment and to measure strain and/or temperature with high accuracy and high spatial resolution. A stepwise optical light source generates an optical pulse having a stepwise distribution of intensity to increase toward the center, and a continuous light source generates continuous light on. The optical pulse is incident on a sensing optical fiber as probe light and the continuous light is incident as pump light to cause a Brillouin scattering phenomenon between the probe light and the pump light. A Brillouin time domain detector determines a Brillouin loss or gain spectrum from the light emerging from the sensing optical fiber and attributed to the Brillouin scattering phenomenon, and measures strain in and/or temperature of the sensing optical fiber in the longitudinal direction thereof based on the determined Brillouin loss or gain spectrum.
patents
