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WO2010136365A1 - Procédé et dispositif pour déterminer l'allongement ou le refoulement d'un réseau à fibres optiques - Google Patents

Procédé et dispositif pour déterminer l'allongement ou le refoulement d'un réseau à fibres optiques Download PDF

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Publication number
WO2010136365A1
WO2010136365A1 PCT/EP2010/056883 EP2010056883W WO2010136365A1 WO 2010136365 A1 WO2010136365 A1 WO 2010136365A1 EP 2010056883 W EP2010056883 W EP 2010056883W WO 2010136365 A1 WO2010136365 A1 WO 2010136365A1
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WO
WIPO (PCT)
Prior art keywords
fiber bragg
bragg grating
fiber
light
grating
Prior art date
Application number
PCT/EP2010/056883
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German (de)
English (en)
Inventor
Jens Bliedtner
Stephan Rinck
Original Assignee
Fachhochschule Jena
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Publication date
Application filed by Fachhochschule Jena filed Critical Fachhochschule Jena
Publication of WO2010136365A1 publication Critical patent/WO2010136365A1/fr

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    • 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
    • G01D5/35303—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 a reference fibre, e.g. interferometric devices
    • 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
    • G01D5/35306—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 an interferometer arrangement
    • G01D5/35309—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 an interferometer arrangement using multiple waves interferometer
    • G01D5/35316—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 an interferometer arrangement using multiple waves interferometer using a Bragg gratings
    • 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

Definitions

  • the invention relates to a method for determining the elongation or compression of a fiber optic grating, preferably in connection with the measurement of changes in length, such as in the evaluation of the vibration or deformation of an object.
  • the invention further relates to a fiber grid deformation sensor operating according to this method.
  • Fiber optic gratings of the type used here are known as fiber Bragg gratings.
  • Fiber Bragg gratings are interference fringes inscribed in optical fibers which act as narrow band filters, reflecting back a certain wavelength from the light incident on the fiber. This wavelength is dependent on the grating period of the interference grating and the refractive index of the optical fiber. If a fiber Bragg grating is firmly connected to an object to be examined for changes in length, for example in the form of expansions or compressions, the elongation or compression of this object also causes an expansion or compression of the optical fiber, thereby changing the grating period of the fiber -Bragg grid and thereby also the Wei- wavelength of the reflected light.
  • the strain or compression of the fiber Bragg grating or the change in the lattice constant caused thereby is referred to in the context of the following description of the invention as a deflection of the fiber Bragg grating.
  • WO 2006/108468 A1 describes the use of a fiber Bragg grating in a spot welding arrangement for joining workpieces.
  • the deformation of welding tongs elements is measured with the fiber Bragg grating, and conclusions are derived from the measurement results on the welding spot quality and thus also on the quality of the welded joint.
  • a disadvantage of the previously known arrangements for determining the elongation or compression of objects by means of fiber optic gratings is the high technical and therefore costly effort for signal conversion, which is required to determine from the wavelength of the reflected light, the change in length and display. This signal conversion has hitherto been carried out by means of spectrometers and is therefore associated with relatively high costs.
  • the object of the invention is to further develop the method known per se with regard to possible cost reduction.
  • the object of the invention is to specify at least one fiber grating deformation sensor operating according to the improved method.
  • the fiber Bragg gratings have the same characteristics, in particular the same center wavelength.
  • the fiber Bragg grating S operates according to the invention in the sense of a sensor. If the fiber Bragg grating S is firmly connected to an object to be examined for unacceptable change in length, the grating period of the fiber Bragg grating S and thus the wavelength ⁇ S, which serves as sensor wavelength, changes with the deformation of the object.
  • the fiber Bragg grating M operates according to the invention in the sense of a modulator. With the periodic stretching and compression or deflection of the fiber Bragg grating M it is achieved that the wavelength ⁇ M, which serves as the modulation wavelength, changes with the same periodic sequence.
  • the method according to the invention can generally be used to control or measure physical quantities, the variation of which, in conjunction with a fiber Bragg grating, results in a change in the wavelength ⁇ S as sensor wavelength.
  • the invention also includes a procedure in which, instead of the periodic deflection of the fiber Bragg grating M, the two selective wavelengths ⁇ M and ⁇ S are kept identical, by the deflection of the fiber Bragg grating M being continuous with the deflection of the fiber Bragg grating S is tracked and closed by measuring the deflection of the fiber Bragg grating M, the modulator, to the position of the fiber Bragg grating S, the sensor.
  • Embodiments of the invention are expressly considered to be equivalent, in which, with a fiber Bragg grating S from the wavelength range ⁇ L, first the wavelength ⁇ S as the sensor wavelength and only then with another fiber Bragg grating M from the remaining spectrum the wavelength ⁇ M as the modulation wavelength is selected. Again, after selection of the wavelengths ⁇ M and ⁇ S, the intensity of the remaining radiation component is evaluated as already described.
  • the invention further relates to a fiber grating deformation sensor operating according to the method described above.
  • the fiber grating deformation sensor according to the invention comprises in its general structure: a light source emitting light with a wavelength range ⁇ L, at least one fiber Bragg grating M for selecting a wavelength ⁇ M from the coupled-in light, at least one fiber Bragg grating S for Selection of a wavelength ⁇ S from the injected light, wherein the coupling of the light with the wavelength range .DELTA. ⁇ L is first provided in the fiber Bragg grating M and then in the fiber Bragg grating S or, conversely, first in the fiber Bragg grating S and then in the fiber Bragg grating M.
  • At least one detector to which the remaining radiation component is directed after selection of the wavelengths ⁇ M and ⁇ S, and whose signal output is connected to a control and evaluation circuit, wherein the control and evaluation circuit is designed for periodic or continuous comparison of the detector output in Dependent on the deviation of the intensity at ⁇ M ⁇ ⁇ S of a given intensity at ⁇ M ⁇ S applied signal and for outputting information about an equal or unequal expansion or compression of the fiber Bragg grating S, wherein each fiber Bragg grating M with a device for generating mechanical vibrations and thus coupled to the periodic deflection.
  • the fiber grating deformation sensor is equipped with a calibration device which is designed to convert the wavelength ⁇ M into the desired physical variable.
  • the desired physical variable can then be measured at the location of the fiber Bragg grating S, the sensor, by comparing the selective wavelengths ⁇ M and ⁇ S.
  • a piezoelectric actuator or a voice coil system is provided for generating the mechanical vibrations.
  • the light source is designed as a broadband fiber optic light source that emits light with a spectral range of 50 nm at a constant intensity.
  • the detector may be formed, for example, as a photodiode.
  • a device instead of the device for generating mechanical vibrations, a device is provided by which the deflection of the fiber ⁇ selected for selection of the wavelength ⁇ M Bragg grating M continuously the deflection of the fiber Bragg grating S. is tracked so that the two wavelengths ⁇ M and ⁇ S are kept identical.
  • the drive and evaluation circuit for measuring the deflection of the fiber Bragg grating M and thus to the determination of the current deflection of the fiber Bragg grating S and the conversion of this deflection is formed in the physical quantity to be determined.
  • FIG. 1 shows an exemplary embodiment of the fiber grating deformation sensor according to the invention, in which the light reflected back from a fiber Bragg grating S is coupled into a fiber Bragg grating M,
  • FIG. 2 shows an embodiment in which the light emitted by the light source polychromatic light passes first a fiber Bragg grating M and then coupled into a fiber Bragg grating S,
  • FIG. 3 shows an embodiment of the fiber grating deformation sensor according to the invention, in which the light emitted by a light source polychromatic light is coupled into a plurality of successively arranged in series fiber Bragg grating S
  • Figure 4 shows an embodiment which is substantially the embodiment of FIG .3, but with an additional detector connected via a separate branch, which provides a reference signal
  • 5 shows an exemplary embodiment in which the light passing through a fiber Bragg grating M is coupled into a fiber Bragg grating S and the light passing through the fiber Bragg grating S is directed onto a detector
  • FIG. 6 shows an exemplary embodiment in which the polychromatic light emitted by the light source is coupled into a plurality of fiber Bragg gratings S which are arranged successively as sensors in series,
  • FIG 7 shows an embodiment of the fiber grating deformation sensor according to the invention, in which the light passing through a fiber Bragg grating M is branched, wherein in each case a fiber Bragg grating S is arranged in several parallel branches, FIG the light emitted by a light source polychromatic light is coupled into a fiber Bragg grating M and the light reflected from the fiber Bragg grating M light is branched, wherein in each case a fiber Bragg grating S is arranged in several parallel branches.
  • FIG. 1 shows a first embodiment of the fiber grating deformation sensor according to the invention.
  • a light source L for example a regulated, fiber-coupled SLED.
  • the wavelength range ⁇ L corresponds to the maximum strain or compression of the fiber Bragg grating M.
  • the light is coupled into a coupling point Y1 of a Y-junction.
  • the coupling point Y3 of the Y-junction the light arrives at about 50% of the intensity and is guided from here via an optical waveguide fiber to a fiber Bragg grating S which is connected to an object to be monitored (not shown in the drawing). is bound.
  • the fiber Bragg grating M and the fiber Bragg grating S have the same center wavelength.
  • the fiber Bragg grating S reflects a wavelength ⁇ S from the light coupled in with the wavelength range ⁇ L.
  • the wavelength ⁇ S is dependent on the actual strain or compression the fiber Bragg grating S, that is, it varies with the extent of the strain or compression of the fiber Bragg grating S and is thereby a measure of the strain or compression of the object positively connected to the fiber Bragg grating S.
  • the wavelength range ⁇ S corresponds to the maximum deflection of the fiber Bragg grating S. The remaining, non-reflected portion of the light passes through the fiber Bragg grating S and is of no importance in connection with the invention described herein.
  • the light of the wavelength ⁇ S reflected by the fiber Bragg grating S returns via the coupling point Y3 back into the Y-branch, now passes through it in the opposite direction and is split due to the branching to the two coupling points Y1 and Y2. Only the radiation component emerging at the coupling point Y2 is further used and guided to a fiber Bragg grating M.
  • M stands here as well as in the embodiments described below, mutatis mutandis, for "modulator".
  • the fiber Bragg grating M is exposed to a mechanical vibration S M of frequency F M and thereby excited to periodic stretching and compression.
  • This is preferably a harmonic oscillation S M.
  • the oscillation S M is generated in the exemplary embodiment described here with a piezoelectric actuator P, which is controlled by an electrical signal coming from a control and evaluation circuit AAS.
  • the amplitude of the oscillation S M must be greater than that expected at the fiber Bragg grating S maximum strain or compression, hereinafter referred to as the maximum deflection.
  • the wavelength range ⁇ S lies within the wavelength range ⁇ M.
  • the fiber Bragg grating M reflects a wavelength ⁇ M oscillating at the frequency F M about the center wavelength of the fiber Bragg grating M, that is, the wavelength ⁇ M varies depending on the amount of strain or compression of the fiber
  • the non-reflected portion of the light comprising the remaining wavelengths of the wavelength range ⁇ L passes through the fiber Bragg grating M and is guided onto an optoelectronic transducer in the form of a detector D, for example a photodiode.
  • the fiber Bragg grating S and the fiber Bragg grating M are in the same displacement. Exactly then the same wavelength is reflected by the fiber Bragg grating M, which is also reflected by the fiber Bragg grating S. That is, if the fiber Bragg grating S and the fiber Bragg grating M are in the same displacement, ⁇ S is equal to ⁇ M. However, as already explained, the fiber Bragg grating S only light with a wavelength ⁇ S comes, and the fiber Bragg grating M only allows light to pass that does not have the wavelength ⁇ M, no light passes through the fiber Bragg grating M if the condition ⁇ S equal to ⁇ M is satisfied.
  • the detector D provides a zero output signal twice per period of the oscillation S M , namely, when the deflection of the fiber Bragg grating S is equal to the deflection of the fiber Bragg grating M, and then, respectively at the fiber Bragg grating S to be measured physical size of the deflection of the fiber Bragg grating S corresponds.
  • the signal output of the detector D is applied to the drive and evaluation circuit AAS, which is designed to measure the times of these zero levels, to compare with the phase position of the oscillation S M and in a relative position of the deflection of the fiber Bragg grating S to convert to the deflection of the fiber Bragg grating M.
  • the deflection of the fiber Bragg grating S or the physical quantity to be measured is determined twice per period of oscillation S M.
  • the further development according to the invention offers the advantage that it is possible to dispense with a technically complex and expensive spectral analysis.
  • the fiber grating deformation sensor it is also possible to obtain absolute position information in the form of physical variables by calibrating this fiber grating deformation sensor with the aid of length measurements or length normal.
  • calibrations based on length measurements or length standards are common in the art and therefore need not be explained in detail here.
  • the light emitted by the light source L first passes into a fiber Bragg grating M.
  • the fiber Bragg grating M with a mechanical, preferably harmonic oscillation S M frequency F M driven and thus excited to a periodic strain and compression. This is done, for example, again with the aid of a piezo actuator P, which is connected via a control line to the drive and evaluation circuit AAS.
  • the amplitude of the oscillation S M is greater here than the maximum deflection to be expected at the fiber Bragg grating S.
  • the fiber Bragg grating M due to the oscillation S M from the wavelength range ⁇ L of the light emitted by the light source L, reflects a wavelength ⁇ M oscillating about its center wavelength at the frequency F M.
  • the light passing through the fiber Bragg grating M thus lacks twice the wavelength ⁇ M changing with the oscillation S M per oscillation period.
  • the light guided through the fiber Bragg grating M is coupled into the coupling point Y1 of a Y-branching element.
  • the light emerging via the coupling point Y3 from the Y-junction with approximately 50% intensity is, again advantageously via an optical fiber LWL, guided to a fiber Bragg grating S.
  • the fiber Bragg grating M and the fiber Bragg grating S also have the same center wavelength.
  • the fiber Bragg grating S reflects a wavelength ⁇ S, which depends on the extent of the strain or compression of the fiber Bragg grating S. If the wavelength ⁇ S is absent in the spectrum of the light incident in the fiber Bragg grating S, the fiber Bragg grating S can not reflect light. Since the light coming from the fiber Bragg grating M and incident into the fiber Bragg grating S lacks all wavelengths within the wavelength range ⁇ L twice per period of the oscillation S M , the wavelength ⁇ S reflected by the fiber Bragg grating S is also missing twice per period.
  • the light reflected by the fiber Bragg grating S with the remaining wavelengths of the wavelength range ⁇ L gets back to the coupling point Y3 of the Y-branch, passes through the Y-branch in the reverse direction and is split. Again, only the radiation component emerging at the coupling point Y3 is used and guided to the detector D.
  • the detector D also supplies an output signal that goes to zero twice per period of the oscillation S M , namely when the excursion of the fiber Bragg grating S is equal to the deflection of the fiber Bragg grating M.
  • the drive and evaluation circuit AAS works here as well as in the embodiment of Figure 1.
  • each fiber Bragg grating S to be provided as a sensor is assigned a fiber Bragg grating M as a modulator and a detector D, as will be shown below with reference to further exemplary embodiments.
  • a fiber Bragg grating M as a modulator and a detector D
  • the polychromatic light emitted by the light source L is in the wavelength range ⁇ L for coupling into a plurality of fiber Bragg gratings (S1, S2,. provided as sensors with different center wavelengths.
  • the light reflected by the fiber Bragg gratings (S1, S2,... Sn) is branched, whereby in each case a fiber Bragg grating (M1, M2,. ..Mn) is present as a modulator.
  • Each of the fiber Bragg gratings (M1, M2, ... Mn) has in common the same center wavelength with one of the fiber Bragg gratings (S1, S2, ... Sn).
  • the light passing through the fiber Bragg gratings (M1, M2, ... Mn) is directed to an associated detector (D1, D2, ... Dn).
  • This variant is suitable for the simultaneous evaluation of several fiber Bragg gratings (S1, S2, ... Sn).
  • the center wavelengths of the fiber Bragg gratings (S1, S2,... Sn) are so different from one another that their wavelength ranges ⁇ M1, ⁇ M2... ⁇ Mn do not overlap but lie within the wavelength range ⁇ L.
  • the evaluation of the signals applied by the detectors (D1, D2, ... Dn) to the drive and evaluation circuit AAS takes place separately for each fiber Bragg grating (M1, M2,... Mn).
  • the light reflected from the fiber Bragg gratings (S1, S2, ... Sn) is divided by means of a splitter, each branch (Z1, Z2, ... Zn) becoming one of the fiber Bragg gratings (M1, M2, ... Mn) leads.
  • the fiber Bragg gratings (M1, M2,... Mn) are also driven here with a preferably harmonic oscillation S M of the frequency F M and thus excited to periodic stretching and compression, for example by means of a fiber which is available for all -Bragg grating (M1, M2, ... Mn) shared piezo actuator P.
  • the amplitude of the oscillation S M is also greater than that at all fiber Bragg gratings (S1, S2, ... Sn) expected maximum deflections.
  • the wavelength ranges ⁇ S1, ⁇ S2 ... ⁇ Sn in which the fiber Bragg gratings (S1, S2,... Sn) are deflected are thereby small. or equal to the wavelength ranges ⁇ M1, ⁇ M2 ... ⁇ Mn in which fiber Bragg gratings (M1, M2, ... Mn) operate.
  • the signal strength which decreases in relation to this with a higher number of fiber Bragg gratings can be compensated for by higher light output of the light source L.
  • FIG. 4 essentially corresponds to the exemplary embodiment according to FIG. 3, but here an additional detector R connected via a separate branch ZR is present, which supplies a reference signal.
  • an additional detector R connected via a separate branch ZR is present, which supplies a reference signal.
  • the light passing through a fiber Bragg grating M is provided for coupling into a fiber Bragg grating S, and the light passing through the fiber Bragg grating S is directed onto a detector D.
  • the light emitted by the light source L polychromatic light with the wavelength range .DELTA. ⁇ L is guided through a series arranged fiber Bragg grating M as a modulator and fiber Bragg grating S as a sensor. If the deflection in the fiber Bragg grating M differs from the deflection in the fiber Bragg grating S, two spectral components, namely the wavelengths ⁇ M and ⁇ S, are taken from the light.
  • the intensity measured at the following detector D is slightly lower than in the case of the same deflection in both fiber Bragg gratings M and S with ⁇ M equal to ⁇ S.
  • the intensity maxima are here evaluated analogously to the intensity minima in the previously described design variants.
  • the order of sensor and modulator is immaterial to the function.
  • the reflected back to the light source L radiation component is relatively high in this arrangement, therefore, the light source L should be operated with a corresponding decoupling. This also applies to the exemplary embodiments described below with reference to FIGS. 2, 6 and 7.
  • the polychromatic light radiated by the light source L is provided for coupling into a plurality of fiber Bragg gratings (S1, S2,... Sn) arranged successively as sensors in series, which differ from one another Have center wavelengths.
  • the fiber Bragg grating (S1, S2, ... Sn) passing light used and is to this Branched purpose, wherein in several parallel branches (Z1, Z2, ... Zn) each have a fiber Bragg grating (M1, M2, ... Mn) is present as a modulator.
  • Mn has the same center wavelength with a corresponding fiber Bragg grating (S1, S2, ... Sn).
  • the light passing through the fiber Bragg gratings (M1, M2,... Mn) is in each case directed separately to an associated detector (D1, D2,... Dn).
  • an additional detector R connected via a separate branch ZR can also be present.
  • the light passing through the fiber Bragg grating M is branched, with fiber Bragg gratings (S1, S2 , ... Sn) are arranged with mutually equal center wavelengths.
  • the light passing through the fiber Bragg gratings (S1, S2, ... Sn) is directed separately to associated detectors (D1, D2, ... Dn).
  • the polychromatic light emitted by the light source L is coupled into a fiber Bragg grating M.
  • the light reflected by the fiber Bragg grating M is branched, wherein in several parallel branches (Z1, Z2,... Zn) fiber Bragg gratings (S1, S2,... Sn) are arranged with mutually equal center wavelengths ,
  • the light passing through the fiber Bragg gratings (S1, S2, ... Sn) is directed separately to associated detectors (D1, D2, ... Dn).
  • the deflections of several fiber Bragg gratings (S1, S2,... Sn) used as sensors are measured using only one fiber Bragg grating M as modulator.
  • the feedback to the light source L is advantageously relatively low.
  • the evaluation of the signals emitted by the detectors is carried out according to the embodiment of Figure 1 on the basis of the negative signal peaks in between the fiber Bragg grating M and the individual fiber Bragg gratings (S1, S2, ... Sn) coincident deflection.
  • an additional detector R connected via a separate branch ZR should be present as a reference detector.

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  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un procédé pour déterminer l'allongement ou le refoulement d'un réseau à fibres optiques. L'invention concerne également un capteur de déformation de réseau à fibres travaillant selon ce procédé. Les étapes de procédé suivantes sont prévues : - à partir de la plage de longueurs d'onde ??L émise par une source de lumière, on sélectionne au moyen d'un réseau de Bragg à fibres M une longueur d'onde ?M dépendante de sa déviation actuelle, on sélectionne à partir du spectre restant une longueur d'onde ?S dépendante de sa déviation actuelle au moyen d'un autre réseau de Bragg à fibres S, et - après la sélection des longueurs d'onde ?M et ?S, on analyse l'intensité de la fraction de rayonnement restante et on déduit une déviation égale ou inégale des deux réseaux de Bragg à fibres M et S. Dans le cas présent, le réseau de Bragg à fibres M déterminé pour la sélection de la longueur d'onde ?M est dévié périodiquement selon l'invention, de sorte que la longueur d'onde ?M a une valeur changeant périodiquement, ou bien - la déviation du réseau de Bragg à fibres M déterminé pour la sélection de la longueur d'onde ?M suit en continu la déviation du réseau de Bragg à fibres S, de sorte que les longueurs d'onde ?M et ?S sont maintenues identiques.
PCT/EP2010/056883 2009-05-26 2010-05-19 Procédé et dispositif pour déterminer l'allongement ou le refoulement d'un réseau à fibres optiques WO2010136365A1 (fr)

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DE102009022953.1 2009-05-26
DE102009022953A DE102009022953A1 (de) 2009-05-26 2009-05-26 Verfahren und Anordnung zum Ermitteln der Dehnung oder Stauchung eines faseroptischen Gitters

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104330414A (zh) * 2014-11-19 2015-02-04 柳州市骏信金属制品有限责任公司 自动感应检知装置
CN114353686A (zh) * 2021-09-10 2022-04-15 重庆交通大学 隧道衬砌的曲率分布智能获取方法及相关装置
CN116295835A (zh) * 2021-12-20 2023-06-23 上海近观科技有限责任公司 基于端面耦合的空间拉曼光谱仪
CN119509941A (zh) * 2024-11-12 2025-02-25 南京航空航天大学 一种大型空间展开机构振动智能预测方法及系统

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015206903A1 (de) * 2015-04-16 2016-10-20 Siemens Aktiengesellschaft Bragg-Gitter-Sensor
GB201713281D0 (en) * 2017-08-18 2017-10-04 Univ Coventry Coriolis flow meter
CN108279037B (zh) * 2017-12-28 2020-05-19 北京交通大学 一种地铁轨道结构实时监测系统的布置方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2268581A (en) * 1992-07-03 1994-01-12 Marconi Gec Ltd Optical fibre diffraction grating sensor
US5380995A (en) * 1992-10-20 1995-01-10 Mcdonnell Douglas Corporation Fiber optic grating sensor systems for sensing environmental effects
US6018160A (en) * 1997-03-22 2000-01-25 British Aerospace Public Limited Company Apparatus for sensing temperature and/or strain in an object with optical fiber Bragg gratings

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1262407B (it) * 1993-09-06 1996-06-19 Finmeccanica Spa Strumentazione utilizzante componenti in ottica integrata per la diagnostica di parti con sensori a fibra ottica inclusi o fissati sulla superficie.
US5410404A (en) * 1993-11-30 1995-04-25 The United States Of America As Represented By The Secretary Of The Navy Fiber grating-based detection system for wavelength encoded fiber sensors
DE19916571A1 (de) * 1999-04-13 2000-11-23 Siemens Ag Einstellbares Bragg-Gitter-Filtermodul
US7109471B2 (en) * 2004-06-04 2006-09-19 Weatherford/Lamb, Inc. Optical wavelength determination using multiple measurable features
DE102005017797B4 (de) 2005-04-13 2010-10-28 Fachhochschule Jena Schweissanordnung, insbesondere zum Verbinden von Werkstücken durch Widerstands- oder Pressschweissen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2268581A (en) * 1992-07-03 1994-01-12 Marconi Gec Ltd Optical fibre diffraction grating sensor
US5380995A (en) * 1992-10-20 1995-01-10 Mcdonnell Douglas Corporation Fiber optic grating sensor systems for sensing environmental effects
US6018160A (en) * 1997-03-22 2000-01-25 British Aerospace Public Limited Company Apparatus for sensing temperature and/or strain in an object with optical fiber Bragg gratings

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
J. ROTHS, C. SUDAN, R. KUTTLER, C. GERZ: "High Precision, Low-Cost Interrogation System for Fiber Bragg Grating Sensors", DGAO PROCEEDINGS, 106 TAGUNG, 20 May 2005 (2005-05-20), XP002596249, ISSN: 1614-8436, Retrieved from the Internet <URL:http://www.dgao-proceedings.de/download/106/106_p8.pdf> [retrieved on 20100812] *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104330414A (zh) * 2014-11-19 2015-02-04 柳州市骏信金属制品有限责任公司 自动感应检知装置
CN114353686A (zh) * 2021-09-10 2022-04-15 重庆交通大学 隧道衬砌的曲率分布智能获取方法及相关装置
CN114353686B (zh) * 2021-09-10 2023-10-20 重庆交通大学 隧道衬砌的曲率分布智能获取方法及相关装置
CN116295835A (zh) * 2021-12-20 2023-06-23 上海近观科技有限责任公司 基于端面耦合的空间拉曼光谱仪
CN116295835B (zh) * 2021-12-20 2023-12-22 上海近观科技有限责任公司 基于端面耦合的空间拉曼光谱仪
CN119509941A (zh) * 2024-11-12 2025-02-25 南京航空航天大学 一种大型空间展开机构振动智能预测方法及系统

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