WO2021192717A1 - Physical quantity measurement device - Google Patents

Physical quantity measurement device Download PDF

Info

Publication number
WO2021192717A1
WO2021192717A1 PCT/JP2021/005422 JP2021005422W WO2021192717A1 WO 2021192717 A1 WO2021192717 A1 WO 2021192717A1 JP 2021005422 W JP2021005422 W JP 2021005422W WO 2021192717 A1 WO2021192717 A1 WO 2021192717A1
Authority
WO
WIPO (PCT)
Prior art keywords
physical quantity
light
measuring device
wavelength
optical sensor
Prior art date
Application number
PCT/JP2021/005422
Other languages
French (fr)
Japanese (ja)
Inventor
顕 小川
圭一 藤田
山手　勉
Original Assignee
長野計器株式会社
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 長野計器株式会社 filed Critical 長野計器株式会社
Publication of WO2021192717A1 publication Critical patent/WO2021192717A1/en

Links

Images

Classifications

    • 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

Definitions

  • the present invention relates to a physical quantity measuring device.
  • a physical quantity measuring device including an optical fiber sensor having a Fabry-Perot etalon composed of a pair of FBGs (fiber bragg gratings) is known (for example, Patent Document 1).
  • the light emitted from the broadband light source is incident on an optical fiber sensor composed of Fabry-Perot etalon by a fiber Bragg grating pair, and the transmitted light of the optical fiber sensor is the wavelength of the transmitted light. It is incident on the interferometer through a bandpass filter centered on the peak.
  • the half-value full width of the transmission spectrum of the optical fiber sensor can be made smaller than the half-value full width of the reflection spectrum of the optical fiber sensor using the conventional FBG, and the coherence length of light becomes long.
  • the difference in optical path length of the interferometer can be made larger than that. Therefore, the measurement resolution can be improved.
  • Patent Document 1 since only the phase information is measured as the output of the interferometer, there is a problem that the absolute value of the wavelength of the optical fiber sensor cannot be obtained and cannot be used for static measurement. ..
  • An object of the present invention is to provide a physical quantity measuring device capable of improving measurement resolution and obtaining an absolute value of wavelength.
  • the physical quantity measuring device of the present invention has a wavelength-variable light source configured so that the wavelength of the emitted light can be changed, and the light emitted from the wavelength-variable light source is incident, depending on the physical quantity acting on the object to be measured.
  • the optical sensor emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved and the information of the absolute value of the output wavelength of the optical sensor can be obtained. Further, since the light is incident on the optical sensor while changing the wavelength of the light, the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a WDM filter required for multiplexing in Patent Document 1 and a bandpass filter required for obtaining narrow-band light of transmitted light can be eliminated.
  • the physical quantity measuring device of the present invention incidents a wideband light source that emits wideband light and the light emitted from the wideband light source, and emits output light having a small half-value and full width according to the physical quantity acting on the object to be measured.
  • An optical sensor that emits light, an interferometer that emits interfering light by incident the output light emitted from the optical sensor, a spectroscope that disperses the interfering light emitted from the interferometer, and the spectroscope. It is characterized by including an optical detection unit for detecting the interference light dispersed by the above.
  • the interfering light emitted from the interferometer is separated by a spectroscope to obtain the wavelength spectrum information of the interfering light, and the phase information of the interferometer output is analyzed using the output light intensity of the optical sensor.
  • the optical sensor emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved and the information of the absolute value of the output wavelength of the optical sensor can be obtained.
  • the interference light is separated and introduced into the detection unit, it is possible to cut a wavelength region unnecessary for detection by analyzing the spectrum of the interference light. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
  • the optical sensor has a measuring sensor element that constitutes Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other.
  • the optical sensor since the optical sensor has a measurement sensor element that constitutes Fabry-Perot Etalon from a pair of fiber Bragg gratings that are arranged close to each other, the half-value full width of the spectrum of light emitted from the measurement sensor element can be reduced. , The measurement resolution can be improved.
  • the optical sensor has a Fizeau interference type measuring sensor element.
  • the optical sensor since the optical sensor has a Fizeau interferometer type measurement sensor element, the half-value full width of the spectrum of the light emitted from the measurement sensor element can be reduced, and the measurement resolution can be improved.
  • the optical sensors having different centers of wavelength peaks are provided.
  • this configuration by arranging a plurality of optical sensors having different center wavelengths in the measured portion, changes in physical quantities at different positions of the object to be measured and changes in different physical quantities such as pressure and temperature can be accurately measured. Can be done.
  • the plurality of optical sensors are provided at the same location on the object to be measured.
  • changes in different physical quantities such as pressure and temperature can be accurately measured at the same location on the object to be measured.
  • the plurality of optical sensors are provided at different locations on the object to be measured.
  • changes in physical quantities at different positions on the object to be measured can be accurately measured.
  • FIG. 6 is an enlarged view of a part of the spectrum of FIG. The figure which superposed the three spectra of FIG.
  • FIG. 1 is a diagram showing a schematic configuration of the physical quantity measuring device 1 of the first embodiment.
  • the physical quantity measuring device 1 is configured to be capable of measuring physical quantities such as pressure, acceleration, displacement, and inclination.
  • the physical quantity measuring device 1 includes a variable wavelength light source 10, a circulator 20, a coupler 30, an isolator 40, an optical sensor 50, a beam splitter 60, an interferometer 70, and a light detection unit 80. And.
  • the wavelength tunable light source 10 is configured so that the wavelength of the emitted light can be changed.
  • the tunable light source 10 is composed of, for example, a tunable laser capable of sweeping a wide band, and is configured to be capable of emitting light having a wavelength of 1200 nm to 1600 nm.
  • the tunable light source 10 may be configured to be capable of emitting light in a wavelength region wider than the illustrated wavelength region, or may be configured to be capable of emitting light in a wavelength region narrower than the exemplified wavelength region. You may.
  • the circulator 20 incidents the light emitted from the tunable light source 10 and sends it to the optical sensor 50 via the coupler 30 and the isolator 40. Further, the circulator 20 incidents the transmitted light output from the optical sensor 50 and sends it to the interferometer 70 via the beam splitter 60.
  • the circulator 20 is not limited to the above configuration, and may be composed of, for example, a beam splitter.
  • the coupler 30 is an optical element that sends the light emitted from the circulator 20 to the optical sensor 50 via the isolator 40 and sends the transmitted light output from the optical sensor 50 to the circulator 20.
  • the coupler 30 is not limited to the above configuration, and may be composed of, for example, a beam splitter.
  • the isolator 40 transmits the light emitted from the coupler 30 and sends it to the optical sensor 50. Further, the isolator 40 blocks a part of the reflected light of the light incident on the optical sensor 50. That is, the isolator 40 transmits only light in the direction from the coupler 30 toward the optical sensor 50.
  • the optical sensor 50 is arranged on an object to be measured (not shown), and is configured to be capable of emitting output light having a small full width at half maximum according to a physical quantity acting on the object to be measured.
  • the optical sensor 50 has a measurement sensor element 51 that injects the light emitted from the coupler 30 via the isolator 40 and outputs the transmitted light to the coupler 30.
  • the measurement sensor element 51 is composed of a pair of fiber Bragg gratings arranged close to each other to form a Fabry-Perot Etalon. Specifically, the pair of fiber Bragg gratings constituting the measurement sensor element 51 are formed at a predetermined distance, and each of them serves as a mirror. Then, the pair of fiber Bragg gratings reflect light in a predetermined wavelength region. As a result, the pair of fiber Bragg gratings constitutes a Fabry-Perot Etalon. In the present embodiment, as described above, the measurement sensor element 51 outputs transmitted light to the coupler 30.
  • the beam splitter 60 is an optical element that splits incident light into a plurality of lights at a predetermined division ratio or combines the plurality of lights.
  • the beam splitter 60 includes a first beam splitter 61 and a second beam splitter 62.
  • the first beam splitter 61 is arranged between the circulator 20 and the interferometer 70. Then, the first beam splitter 61 splits the light emitted from the circulator 20 into two lights and causes them to enter the interferometer 70.
  • the second beam splitter 62 is arranged between the interferometer 70 and the photodetector 80. Then, the second beam splitter 62 causes interference by combining the two lights emitted from the interferometer 70, and splits the interference light into three to incident on the photodetector 80.
  • the three interference lights demultiplexed by the second beam splitter 62 are different in phase by 2 ⁇ / 3.
  • the interferometer 70 causes the two lights emitted from the first beam splitter 61 to interfere with each other and outputs the interferometric light.
  • the interferometer 70 is composed of a so-called Mach-Zehnder type interferometer, and has two optical paths 71 and 72 for providing an optical path length difference.
  • the light detection unit 80 is configured to be able to detect the interference light emitted from the interferometer 70.
  • the photodetector 80 includes a photoelectric converter 81, an amplifier 82, an AD converter 83, and an MPU 84.
  • the photoelectric converter 81 incidents the interference light emitted from the interferometer 70 and converts it into an electric signal.
  • three photoelectric converters 81 are provided corresponding to the three interference lights demultiplexed by the second beam splitter 62.
  • the amplifier 82 amplifies the electric signal converted by the photoelectric converter 81.
  • three amplifiers 82 are provided according to the photoelectric converter 81.
  • the AD converter 83 converts the electric signal amplified by the amplifier 82 into a digital signal and causes the MPU 84 to input the electric signal.
  • three AD converters 83 are provided according to the amplifier 82.
  • the MPU 84 is a so-called Micro Processing Unit, and calculates a physical quantity acting on an object to be measured by performing a predetermined calculation based on a digital signal output from the AD converter 83. The method of calculating the physical quantity by the MPU 84 will be described later.
  • the MPU 84 is not limited to the above configuration, and may be composed of, for example, a CPU (Central Processing Unit).
  • FIG. 2 is a diagram showing the relationship between the spectrum transmitted from the optical sensor 50 and the wavelength
  • FIG. 3 is an enlarged view of the peak portion of the spectrum of FIG. 2, and FIG. It is the figure which superposed the spectrum.
  • the wavelength spectrum information of the interference light as shown in FIGS. 2 and 3 can be obtained by sweeping the wavelength of the light emitted by the tunable light source 10.
  • the three wavelength spectrum information shown in FIG. 2 correspond to the electric signals amplified by the three amplifiers 82, respectively.
  • the spectral information shown in FIG. 4 can be obtained by superimposing the electric signals amplified by these three amplifiers 82. As shown in FIG.
  • the transmittance is almost 0 over a predetermined wavelength band on both sides of the side, and further, the transmittance increases from that wavelength band toward both the short wavelength and the long wavelength, and then is attenuated.
  • the center wavelength ⁇ of the optical sensor 50 is an example, and an optical sensor 50 having a center wavelength different from the above may be used.
  • the light intensity detected by the photoelectric converter 81 draws a sine wave as the wavelength of the optical sensor 50 changes.
  • the phase change ⁇ of this sine wave can be expressed by the mathematical formula (1).
  • Equation (1) lambda is the wavelength of the optical sensor 50, n e is the effective refractive index of the core of the optical fiber, d represents the difference in optical path length of the two optical paths 71, 72 of the interferometer 70, [Delta] [lambda] is the optical sensor 50 It is the amount of change in wavelength of.
  • the amount of wavelength change can be calculated conversely.
  • Demodulation of the phase change is performed using the output voltage of the amplifier 82.
  • the output voltage V n of the three amplifiers 82 can be expressed by the mathematical formula (2).
  • ⁇ n is a constant representing the signal amplitude of each of the three amplifiers 82 due to the path loss of light, individual differences of the photoelectric converter 81, etc.
  • C is the dark current of the photoelectric converter 81 and the amplifier 82.
  • V 1 is the voltage value of the first amplifier 82 of the three amplifiers 82.
  • the amount of phase change can be calculated from the outputs of these three amplifiers 82 using the equation (3).
  • ⁇ n is a disturbance component due to a transient intensity change of light
  • ⁇ 2 is a disturbance due to a transient intensity change of light contained in the signal output from the second amplifier 82. It is a component
  • ⁇ 3 is a disturbance component due to a transient intensity change of light contained in the signal output from the third amplifier 82.
  • the transient intensity change of light occurs in common with ⁇ 2 and ⁇ 3 , so the calculation is performed by simply inserting the constant 1. This changes due to fluctuations in the light intensity of the light source and fluctuations in the optical fiber loss due to disturbance factors (stress fluctuations, temperature fluctuations) applied to the optical fibers in the path.
  • the amount of change in wavelength can be calculated by performing the calculation of the formula (3) with the MPU 84, calculating the amount of phase change from the three outputs of the amplifier 82, and then performing the calculation of the formula (1).
  • the optical sensor 50 mounted so as to be affected by the change in the physical quantity of the object to be measured outputs the change in the physical quantity of the object to be measured as a change in the peak wavelength. Since the amount of change in wavelength and the amount of change in physical quantity are usually in a proportional relationship, the physical quantity can be obtained.
  • the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved. Further, the portion of the spectrum other than the signal obtained by the optical sensor 50 has a trigonometric waveform generated by the interferometer 70 as shown in the mathematical formula (4). Then, from the spectral information shown in FIGS. 2 and 3, the optical path length difference d of the interferometer 70 can be obtained by using a technique such as curve fitting.
  • the absolute value information ⁇ C of the wavelength can also be calculated by the following mathematical formula (5).
  • the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
  • the phase information of the output of the interferometer 70 is obtained from the output light intensity of the optical sensor 50 while obtaining the wavelength spectrum information of the interference light. It can be obtained by analysis using. Further, the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved, and information on the absolute value of the output wavelength of the optical sensor 50 can be obtained. Further, since the light is incident on the optical sensor 50 while changing the wavelength of the light, the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
  • the optical sensor 50 since the optical sensor 50 has a measurement sensor element 51 that constitutes a Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other, the light emitted from the measurement sensor element 51 The half-value full width of the spectrum can be reduced, and the measurement resolution can be improved.
  • the physical quantity measuring device 1A according to the second embodiment of the present invention will be described with reference to the drawings.
  • the second embodiment is different from the first embodiment in that the optical sensor 50A has a measurement sensor element 51A that reflects the light incident from the circulator 20A and outputs the reflected light to the circulator 20A.
  • the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
  • FIG. 5 is a diagram showing a schematic configuration of the physical quantity measuring device 1A of the second embodiment.
  • the physical quantity measuring device 1A includes a wavelength variable light source 10, a circulator 20A, an optical sensor 50A, a beam splitter 60, an interferometer 70, and a light detection unit 80.
  • the circulator 20A is configured in the same manner as the circulator 20 of the first embodiment. Then, in the present embodiment, the circulator 20A incidents the light emitted from the tunable light source 10 and sends it to the optical sensor 50A. Further, the circulator 20A incidents the reflected light output from the optical sensor 50A and sends it to the interferometer 70 via the beam splitter 60.
  • the circulator 20A may be composed of, for example, a beam splitter as in the first embodiment.
  • optical sensor 50A The optical sensor 50A is arranged on the object to be measured (not shown) as in the first embodiment described above, and is configured to be capable of emitting output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. ing.
  • the optical sensor 50A has a measurement sensor element 51A that incidents the light emitted from the circulator 20A and outputs the reflected light to the circulator 20A.
  • the measurement sensor element 51A is composed of a pair of fiber Bragg gratings arranged close to each other, and constitutes a Fabry-Perot Etalon, as in the first embodiment described above. In the present embodiment, as described above, the measurement sensor element 51A outputs the reflected light to the circulator 20A.
  • FIG. 6 is a diagram showing the relationship between the spectrum reflected from the optical sensor 50A and the wavelength
  • FIG. 7 is an enlarged view of a part of the spectrum of FIG. 6, and FIG. It is the figure which superposed the spectrum.
  • the wavelength spectrum information of the interference light as shown in FIGS. 6 and 7 can be obtained by sweeping the wavelength of the light emitted by the tunable light source 10 as in the first embodiment described above. ..
  • the three wavelength spectrum information shown in FIG. 6 correspond to the electric signals amplified by the three amplifiers 82, respectively. Further, the spectral information shown in FIG.
  • the reflectance is about 0.7 over a predetermined wavelength band on both sides, and the reflectance is further attenuated from that wavelength band toward both the short wavelength and the long wavelength. That is, the tendency is completely opposite to the spectrum of the transmitted light of the first embodiment described above.
  • the center wavelength ⁇ of the optical sensor 50A is an example, and an optical sensor 50A having a center wavelength different from the above may be used.
  • the intensity I m of the reflected light detected by the photoelectric converter 81, except for the part of a very narrow band is cut by the Fabry-Perot interferometer, it can be represented by Equation (6).
  • S m the actual relative measured signal S m of the photoelectric converter 81 (S m -I m) curve fitting, such as 2 becomes minimum, A m , A, b, d can be obtained.
  • Equation (7) by subtracting the measured signal S m from I m obtained in Equation (6), the output voltage V has a meaning similar to the first embodiment using the transmitted light n can be calculated.
  • the amount of phase change can be calculated from the outputs of the three amplifiers 82 using the mathematical formula (3) as in the first embodiment described above. Therefore, the wavelength change amount can be calculated by performing the calculation of the formula (3) with the MPU 84, calculating the phase change amount from the three outputs of the amplifier 82, and then performing the calculation of the formula (1).
  • the optical sensor 50A mounted so as to be affected by a change in the physical quantity of the object to be measured outputs the change in the physical quantity of the object to be measured as a change in peak wavelength. Since the amount of change in wavelength and the amount of change in physical quantity are usually in a proportional relationship, the physical quantity can be obtained. Further, similarly to the first embodiment described above, the absolute value information ⁇ C of the wavelength can also be calculated by the mathematical formula (5).
  • the third embodiment is different from the first and second embodiments in that the wideband light source 11 is used as the light source and the spectroscope 90 is arranged on the secondary side of the interferometer 70.
  • the same components as those in the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.
  • FIG. 9 is a diagram showing a schematic configuration of the physical quantity measuring device 1B of the third embodiment.
  • the physical quantity measuring device 1B includes a broadband light source 11, a circulator 20, a coupler 30, an isolator 40, an optical sensor 50, a beam splitter 60, an interferometer 70, a spectroscope 90, and the like. It is provided with an optical detection unit 80.
  • the wideband light source 11 is a light source that emits light having a wide band wavelength.
  • the wideband light source 11 is, for example, an SC (Super Continuum) light source, and is configured to be capable of emitting light in a wavelength region of 1250 nm to 1650 nm.
  • the broadband light source 11 is not limited to the above configuration, and may be a combination of an ASE (Amplified Spontaneous Emission) light source, an SLD (Super Luminescent Diode) light source, or the like.
  • the wideband light source 11 may be configured to be capable of emitting light in a wavelength region wider than the illustrated wavelength region, or may be configured to be capable of emitting light in a wavelength region narrower than the illustrated wavelength region. May be good.
  • the spectroscope 90 injects and disperses the interference light emitted from the interferometer 70.
  • three spectroscopes 90 are provided corresponding to the three interference lights demultiplexed by the second beam splitter 62.
  • the physical quantity acting on the object to be measured is measured by analyzing the interference light in which the transmitted light of the optical sensor 50 is interfered with by the interference meter 70.
  • the wavelength spectrum information of the interference light can be obtained by splitting the interference light with the spectroscope 90. Therefore, the absolute value information ⁇ C of the output wavelength of the optical sensor 50 can be obtained as in the first embodiment described above.
  • the interference light emitted from the interference meter 70 is separated by the spectroscope 90, so that the phase information of the interference meter output is output from the optical sensor 50 while obtaining the wavelength spectrum information of the interference light. It can be obtained by analysis using light intensity. Further, the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved, and information on the absolute value of the output wavelength of the optical sensor 50 can be obtained. Further, since the interference light is separated and introduced into the detection unit, it is possible to cut a wavelength region unnecessary for detection by analyzing the spectrum of the interference light. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
  • the physical quantity measuring device 1C according to the fourth embodiment of the present invention will be described with reference to the drawings.
  • the fourth embodiment is different from the third embodiment in that the optical sensor 50A has a measurement sensor element 51A that reflects the light incident from the circulator 20A and outputs the reflected light to the circulator 20A.
  • the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
  • FIG. 10 is a diagram showing a schematic configuration of the physical quantity measuring device 1C of the fourth embodiment.
  • the physical quantity measuring device 1C includes a broadband light source 11, a circulator 20A, an optical sensor 50A, a beam splitter 60, an interferometer 70, a spectroscope 90, and a light detection unit 80.
  • the physical quantity acting on the object to be measured is measured by analyzing the interference light in which the reflected light of the optical sensor 50A is interfered with by the interference meter 70.
  • the wavelength spectrum information of the interference light can be obtained by splitting the interference light with the spectroscope 90. Therefore, the absolute value information ⁇ C of the output wavelength of the optical sensor 50A can be obtained as in the second embodiment described above.
  • the optical sensors 50 and 50A are configured to include measurement sensor elements 51 and 51A constituting Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other.
  • the optical sensor may be configured to include a Fizeau interference type measurement sensor element.
  • the interferometer 70 was composed of a Mach-Zehnder type interferometer, but the present invention is not limited to this.
  • the interferometer may be composed of a Michaelson type interferometer.
  • the physical quantity measuring devices 1, 1A, 1B, and 1C are provided with one optical sensor 50, 50A, but the present invention is not limited to this.
  • the physical quantity measuring device may be provided with a plurality of optical sensors having different centers of wavelength peaks.
  • the plurality of optical sensors may be provided at the same location on the object to be measured. With this configuration, changes in different physical quantities such as pressure and temperature can be accurately measured at the same location of the object to be measured. Further, the plurality of optical sensors may be provided at different locations on the object to be measured. With this configuration, changes in physical quantities at different positions of the object to be measured can be accurately measured.
  • the physical quantity measuring devices 1 and 1C are configured to include the coupler 30 and the isolator 40, but the present invention is not limited thereto.
  • the physical quantity measuring devices 1 and 1C may be configured to include a circulator instead of the coupler 30 and the isolator 40.
  • 1,1A, 1B, 1C Physical quantity measuring device, 10 ... Variable wavelength light source, 11 ... Wideband light source, 20,20A ... Circulator, 30 ... Coupler, 40 ... Isolator, 50,50A ... Optical sensor, 51,51A ... For measurement Sensor element, 60 ... beam splitter, 61 ... first beam splitter, 62 ... second beam splitter, 70 ... interferometer, 71 ... optical path, 72 ... optical path, 80 ... optical detector, 81 ... photoelectric converter, 82 ... amplifier , 83 ... AD converter, 84 ... MPU, 90 ... spectroscope.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)

Abstract

A physical quantity measurement device (1) comprises: a variable-wavelength light source (10) configured so that the wavelength of light emitted thereby can be modified; an optical sensor (50) on which light emitted from the variable-wavelength light source (10) is incident, and which emits output light having a small full width at half maximum in accordance with a physical quantity acting on a substance to be measured; an interferometer (70) on which the output light emitted from the optical sensor (50) is incident, and which emits interference light; and a light detector (80) that detects the interference light emitted from the interferometer (70).

Description

物理量測定装置Physical quantity measuring device
　本発明は、物理量測定装置に関する。 The present invention relates to a physical quantity measuring device.
　一対となるＦＢＧ（ファイバブラッググレーティング）から構成されたファブリペローエタロンを有する光ファイバセンサを備える物理量測定装置が知られている（例えば、特許文献１など）。 A physical quantity measuring device including an optical fiber sensor having a Fabry-Perot etalon composed of a pair of FBGs (fiber bragg gratings) is known (for example, Patent Document 1).
　特許文献１の物理量測定装置では、広帯域光源から出射される光をファイバブラッググレーティング対によるファブリペローエタロンで構成された光ファイバセンサに入射し、当該光ファイバセンサの透過光を、当該透過光の波長ピークを中心とするバンドパスフィルタを介して、干渉計に入射させている。
　これにより、光ファイバセンサの透過スペクトルの半値全幅を、従来のＦＢＧを用いた光ファイバセンサの反射スペクトルの半値全幅よりも小さくでき、光のコヒーレンス長が長くなるため、従来のＦＢＧを用いた場合よりも干渉計の光路長差を大きくすることができる。このため、測定分解能を向上することができる。 In the physical quantity measuring device of Patent Document 1, the light emitted from the broadband light source is incident on an optical fiber sensor composed of Fabry-Perot etalon by a fiber Bragg grating pair, and the transmitted light of the optical fiber sensor is the wavelength of the transmitted light. It is incident on the interferometer through a bandpass filter centered on the peak.
As a result, the half-value full width of the transmission spectrum of the optical fiber sensor can be made smaller than the half-value full width of the reflection spectrum of the optical fiber sensor using the conventional FBG, and the coherence length of light becomes long. The difference in optical path length of the interferometer can be made larger than that. Therefore, the measurement resolution can be improved.
特開２０１１－１４９８７６号公報Japanese Unexamined Patent Publication No. 2011-149876
　しかしながら、特許文献１では、干渉計の出力として位相情報のみを測定しているため、光ファイバセンサの波長の絶対値を得ることができず、静的な測定に用いることができないといった問題がある。 However, in Patent Document 1, since only the phase information is measured as the output of the interferometer, there is a problem that the absolute value of the wavelength of the optical fiber sensor cannot be obtained and cannot be used for static measurement. ..
　本発明の目的は、測定分解能を向上でき、かつ、波長の絶対値を得ることができる物理量測定装置を提供することにある。 An object of the present invention is to provide a physical quantity measuring device capable of improving measurement resolution and obtaining an absolute value of wavelength.
　本発明の物理量測定装置は、出射する光の波長を変更可能に構成された波長可変光源と、前記波長可変光源から出射される前記光を入射して、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する光学センサと、前記光学センサから出射された前記出力光を入射して、干渉光を出射する干渉計と、前記干渉計から出射される前記干渉光を検出する光検出部と、を備えることを特徴とする。 The physical quantity measuring device of the present invention has a wavelength-variable light source configured so that the wavelength of the emitted light can be changed, and the light emitted from the wavelength-variable light source is incident, depending on the physical quantity acting on the object to be measured. Detects an optical sensor that emits output light having a small half-value full width, an interferometer that emits interfering light by injecting the output light emitted from the optical sensor, and the interfering light emitted from the interferometer. It is characterized in that it includes an optical detection unit.
　本発明では、波長可変光源が出射する光の波長を掃引することで、干渉光の波長スペクトル情報を得ながら、干渉計出力の位相情報を光学センサの出力光強度を用いた解析により得ることができる。また、光学センサは、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する。そのため、測定分解能を向上でき、かつ、光学センサの出力波長の絶対値の情報を得ることができる。
　さらに、光の波長を変更しながら光学センサに入射させるので、干渉光を時間的に解析することにより、検出に不要な波長領域をカットすることができる。そのため、波長領域をカットするための光学機器、例えば、特許文献１において多重化に必要なＷＤＭフィルタや、透過光の狭帯域光を得るのに必要なバンドパスフィルタを不要にできる。 In the present invention, by sweeping the wavelength of the light emitted by the variable wavelength light source, it is possible to obtain the phase information of the output of the interferometer by analysis using the output light intensity of the optical sensor while obtaining the wavelength spectrum information of the interference light. can. Further, the optical sensor emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved and the information of the absolute value of the output wavelength of the optical sensor can be obtained.
Further, since the light is incident on the optical sensor while changing the wavelength of the light, the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a WDM filter required for multiplexing in Patent Document 1 and a bandpass filter required for obtaining narrow-band light of transmitted light can be eliminated.
　本発明の物理量測定装置は、広帯域の光を出射する広帯域光源と、前記広帯域光源から出射される前記光を入射して、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する光学センサと、前記光学センサから出射された前記出力光を入射して、干渉光を出射する干渉計と、前記干渉計から出射される前記干渉光を分光する分光器と、前記分光器により分光された前記干渉光を検出する光検出部と、を備えることを特徴とする。 The physical quantity measuring device of the present invention incidents a wideband light source that emits wideband light and the light emitted from the wideband light source, and emits output light having a small half-value and full width according to the physical quantity acting on the object to be measured. An optical sensor that emits light, an interferometer that emits interfering light by incident the output light emitted from the optical sensor, a spectroscope that disperses the interfering light emitted from the interferometer, and the spectroscope. It is characterized by including an optical detection unit for detecting the interference light dispersed by the above.
　本発明では、干渉計から出射される干渉光を分光器にて分光することで、干渉光の波長スペクトル情報を得ながら、干渉計出力の位相情報を光学センサの出力光強度を用いた解析により得ることができる。また、光学センサは、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する。そのため、測定分解能を向上でき、かつ、光学センサの出力波長の絶対値の情報を得ることができる。
　さらに、干渉光を分光して検出部に導入させるので、干渉光のスペクトルを解析することにより、検出に不要な波長領域をカットすることができる。そのため、波長領域をカットするための光学機器、例えば、バンドパスフィルタを不要にできる。 In the present invention, the interfering light emitted from the interferometer is separated by a spectroscope to obtain the wavelength spectrum information of the interfering light, and the phase information of the interferometer output is analyzed using the output light intensity of the optical sensor. Obtainable. Further, the optical sensor emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved and the information of the absolute value of the output wavelength of the optical sensor can be obtained.
Further, since the interference light is separated and introduced into the detection unit, it is possible to cut a wavelength region unnecessary for detection by analyzing the spectrum of the interference light. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
　本発明の物理量測定装置において、前記光学センサは、互いに近接配置された一対のファイバブラッググレーティングからファブリペローエタロンを構成する測定用センサ素子を有することが好ましい。
　この構成では、光学センサは、互いに近接配置された一対のファイバブラッググレーティングからファブリペローエタロンを構成する測定用センサ素子を有するので、測定用センサ素子から出射される光のスペクトルの半値全幅を小さくでき、測定分解能を向上させることができる。 In the physical quantity measuring device of the present invention, it is preferable that the optical sensor has a measuring sensor element that constitutes Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other.
In this configuration, since the optical sensor has a measurement sensor element that constitutes Fabry-Perot Etalon from a pair of fiber Bragg gratings that are arranged close to each other, the half-value full width of the spectrum of light emitted from the measurement sensor element can be reduced. , The measurement resolution can be improved.
　本発明の物理量測定装置において、前記光学センサは、フィゾー干渉型の測定用センサ素子を有することが好ましい。
　この構成では、光学センサは、フィゾー干渉型の測定用センサ素子を有するので、測定用センサ素子から出射される光のスペクトルの半値全幅を小さくでき、測定分解能を向上させることができる。 In the physical quantity measuring device of the present invention, it is preferable that the optical sensor has a Fizeau interference type measuring sensor element.
In this configuration, since the optical sensor has a Fizeau interferometer type measurement sensor element, the half-value full width of the spectrum of the light emitted from the measurement sensor element can be reduced, and the measurement resolution can be improved.
　本発明の物理量測定装置において、波長ピークの中心がそれぞれ異なる複数の前記光学センサが設けられることが好ましい。
　この構成では、中心波長が異なる光学センサを被測定部に複数配置することで、被測定物の異なる位置での物理量の変化や、例えば、圧力および温度といった異なる物理量の変化を正確に測定することができる。 In the physical quantity measuring device of the present invention, it is preferable that a plurality of the optical sensors having different centers of wavelength peaks are provided.
In this configuration, by arranging a plurality of optical sensors having different center wavelengths in the measured portion, changes in physical quantities at different positions of the object to be measured and changes in different physical quantities such as pressure and temperature can be accurately measured. Can be done.
　本発明の物理量測定装置において、複数の前記光学センサは、被測定物における同じ箇所に設けられることが好ましい。
　この構成では、複数の光学センサが被測定物における同じ箇所に設けられるので、被測定物の同じ箇所において、例えば、圧力および温度といった異なる物理量の変化を正確に測定することができる。 In the physical quantity measuring device of the present invention, it is preferable that the plurality of optical sensors are provided at the same location on the object to be measured.
In this configuration, since a plurality of optical sensors are provided at the same location on the object to be measured, changes in different physical quantities such as pressure and temperature can be accurately measured at the same location on the object to be measured.
　本発明の物理量測定装置において、複数の前記光学センサは、被測定物における異なる箇所にそれぞれ設けられることが好ましい。
　この構成では、複数の光学センサが被測定物における異なる箇所にそれぞれ設けられるので、被測定物の異なる位置での物理量の変化を正確に測定することができる。 In the physical quantity measuring device of the present invention, it is preferable that the plurality of optical sensors are provided at different locations on the object to be measured.
In this configuration, since a plurality of optical sensors are provided at different locations on the object to be measured, changes in physical quantities at different positions on the object to be measured can be accurately measured.
第１実施形態に係る物理量測定装置の概略構成を示す図。The figure which shows the schematic structure of the physical quantity measuring apparatus which concerns on 1st Embodiment. 第１実施形態の光学センサの透過光のスペクトルと波長との関係を示す図。The figure which shows the relationship between the spectrum and the wavelength of the transmitted light of the optical sensor of 1st Embodiment. 図２のスペクトルのピーク部を拡大した図。The figure which enlarged the peak part of the spectrum of FIG. 図２の３つのスペクトルを重ね合わせた図。The figure which superposed the three spectra of FIG. 第２実施形態に係る物理量測定装置の概略構成を示す図。The figure which shows the schematic structure of the physical quantity measuring apparatus which concerns on 2nd Embodiment. 第２実施形態の光学センサの反射光のスペクトルと波長との関係を示す図。The figure which shows the relationship between the spectrum and the wavelength of the reflected light of the optical sensor of 2nd Embodiment. 図６のスペクトルの一部を拡大した図。FIG. 6 is an enlarged view of a part of the spectrum of FIG. 図６の３つのスペクトルを重ね合わせた図。The figure which superposed the three spectra of FIG. 第３実施形態に係る物理量測定装置の概略構成を示す図。The figure which shows the schematic structure of the physical quantity measuring apparatus which concerns on 3rd Embodiment. 第４実施形態に係る物理量測定装置の概略構成を示す図。The figure which shows the schematic structure of the physical quantity measuring apparatus which concerns on 4th Embodiment.
　［第１実施形態］
　本発明の第１実施形態の物理量測定装置１を図面に基づいて説明する。
　図１は、第１実施形態の物理量測定装置１の概略構成を示す図である。なお、物理量測定装置１は、圧力、加速度、変位、傾斜などの物理量を測定可能に構成されている。
　図１に示すように、物理量測定装置１は、波長可変光源１０と、サーキュレータ２０と、カプラ３０と、アイソレータ４０と、光学センサ５０と、ビームスプリッタ６０と、干渉計７０と、光検出部８０とを備える。 [First Embodiment]
The physical quantity measuring device 1 of the first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of the physical quantity measuring device 1 of the first embodiment. The physical quantity measuring device 1 is configured to be capable of measuring physical quantities such as pressure, acceleration, displacement, and inclination.
As shown in FIG. 1, the physical quantity measuring device 1 includes a variable wavelength light source 10, a circulator 20, a coupler 30, an isolator 40, an optical sensor 50, a beam splitter 60, an interferometer 70, and a light detection unit 80. And.
　［波長可変光源１０］
　波長可変光源１０は、出射する光の波長を変更可能に構成されている。本実施形態では、波長可変光源１０は、例えば、広帯域を掃引可能なチューナブルレーザにより構成されており、１２００ｎｍ～１６００ｎｍの波長の光を出射可能に構成されている。
　なお、波長可変光源１０は、例示した波長領域よりも広い波長領域の光を出射可能に構成されていてもよく、あるいは、例示した波長領域よりも狭い波長領域の光を出射可能に構成されていてもよい。 [Tunable light source 10]
The wavelength tunable light source 10 is configured so that the wavelength of the emitted light can be changed. In the present embodiment, the tunable light source 10 is composed of, for example, a tunable laser capable of sweeping a wide band, and is configured to be capable of emitting light having a wavelength of 1200 nm to 1600 nm.
The tunable light source 10 may be configured to be capable of emitting light in a wavelength region wider than the illustrated wavelength region, or may be configured to be capable of emitting light in a wavelength region narrower than the exemplified wavelength region. You may.
　［サーキュレータ２０］
　サーキュレータ２０は、波長可変光源１０から出射された光を入射して、カプラ３０およびアイソレータ４０を介して光学センサ５０に送る。さらに、サーキュレータ２０は、光学センサ５０から出力された透過光を入射して、ビームスプリッタ６０を介して干渉計７０に送る。
　なお、サーキュレータ２０は、上記構成に限られず、例えば、ビームスプリッタから構成されていてもよい。 [Circulator 20]
The circulator 20 incidents the light emitted from the tunable light source 10 and sends it to the optical sensor 50 via the coupler 30 and the isolator 40. Further, the circulator 20 incidents the transmitted light output from the optical sensor 50 and sends it to the interferometer 70 via the beam splitter 60.
The circulator 20 is not limited to the above configuration, and may be composed of, for example, a beam splitter.
　［カプラ３０］
　カプラ３０は、サーキュレータ２０から出射された光を、アイソレータ４０を介して光学センサ５０に送るとともに、光学センサ５０から出力された透過光をサーキュレータ２０に送る光学素子である。
　なお、カプラ３０は、上記構成に限られるものではなく、例えば、ビームスプリッタから構成されていてもよい。 [Coupler 30]
The coupler 30 is an optical element that sends the light emitted from the circulator 20 to the optical sensor 50 via the isolator 40 and sends the transmitted light output from the optical sensor 50 to the circulator 20.
The coupler 30 is not limited to the above configuration, and may be composed of, for example, a beam splitter.
　［アイソレータ４０］
　アイソレータ４０は、カプラ３０から出射された光を透過して、光学センサ５０に送る。また、アイソレータ４０は、光学センサ５０に入射された光のうち、反射された一部の光を遮断する。すなわち、アイソレータ４０は、カプラ３０から光学センサ５０に向かう方向の光のみを透過させる。 [Isolator 40]
The isolator 40 transmits the light emitted from the coupler 30 and sends it to the optical sensor 50. Further, the isolator 40 blocks a part of the reflected light of the light incident on the optical sensor 50. That is, the isolator 40 transmits only light in the direction from the coupler 30 toward the optical sensor 50.
　［光学センサ５０］
　光学センサ５０は、図示略の被測定物に配置されており、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射可能に構成されている。本実施形態では、光学センサ５０は、アイソレータ４０を介してカプラ３０から出射された光を入射して、その透過光をカプラ３０に出力する測定用センサ素子５１を有する。 [Optical sensor 50]
The optical sensor 50 is arranged on an object to be measured (not shown), and is configured to be capable of emitting output light having a small full width at half maximum according to a physical quantity acting on the object to be measured. In the present embodiment, the optical sensor 50 has a measurement sensor element 51 that injects the light emitted from the coupler 30 via the isolator 40 and outputs the transmitted light to the coupler 30.
　測定用センサ素子５１は、互いに近接配置された一対のファイバブラッググレーティングから構成され、ファブリペローエタロンを構成する。具体的には、測定用センサ素子５１を構成する一対のファイバブラッググレーティングは、所定の距離を隔てて形成されており、それぞれミラーの役割を有する。そして、一対のファイバブラッググレーティングは、所定の波長領域の光を反射する。これにより、当該一対のファイバブラッググレーティングは、ファブリペローエタロンを構成する。本実施形態では、前述したように、測定用センサ素子５１は、透過光をカプラ３０に出力する。 The measurement sensor element 51 is composed of a pair of fiber Bragg gratings arranged close to each other to form a Fabry-Perot Etalon. Specifically, the pair of fiber Bragg gratings constituting the measurement sensor element 51 are formed at a predetermined distance, and each of them serves as a mirror. Then, the pair of fiber Bragg gratings reflect light in a predetermined wavelength region. As a result, the pair of fiber Bragg gratings constitutes a Fabry-Perot Etalon. In the present embodiment, as described above, the measurement sensor element 51 outputs transmitted light to the coupler 30.
　［ビームスプリッタ６０］
　ビームスプリッタ６０は、入射した光を所定の分割比で複数の光に分波する、または、複数の光を合波する光学素子である。本実施形態では、ビームスプリッタ６０は、第１ビームスプリッタ６１と、第２ビームスプリッタ６２とを有する。 [Beam Splitter 60]
The beam splitter 60 is an optical element that splits incident light into a plurality of lights at a predetermined division ratio or combines the plurality of lights. In this embodiment, the beam splitter 60 includes a first beam splitter 61 and a second beam splitter 62.
　第１ビームスプリッタ６１は、サーキュレータ２０と干渉計７０との間に配置される。そして、第１ビームスプリッタ６１は、サーキュレータ２０から出射された光を２つの光に分波して、干渉計７０に入射させる。
　第２ビームスプリッタ６２は、干渉計７０と光検出部８０との間に配置される。そして、第２ビームスプリッタ６２は、干渉計７０から出射された２つの光を合波させることで干渉させるとともに、当該干渉光を３つに分波して、光検出部８０に入射させる。なお、第２ビームスプリッタ６２により分波された３つの干渉光は、それぞれ位相が２π／３ずつ異なっている。 The first beam splitter 61 is arranged between the circulator 20 and the interferometer 70. Then, the first beam splitter 61 splits the light emitted from the circulator 20 into two lights and causes them to enter the interferometer 70.
The second beam splitter 62 is arranged between the interferometer 70 and the photodetector 80. Then, the second beam splitter 62 causes interference by combining the two lights emitted from the interferometer 70, and splits the interference light into three to incident on the photodetector 80. The three interference lights demultiplexed by the second beam splitter 62 are different in phase by 2π / 3.
　［干渉計７０］
　干渉計７０は、第１ビームスプリッタ６１から出射された２つの光を干渉させて、干渉光を出力する。本実施形態では、干渉計７０は、所謂マッハツェンダー型干渉計により構成されており、光路長差を設けるための２つの光路７１，７２を有する。 [Interferometer 70]
The interferometer 70 causes the two lights emitted from the first beam splitter 61 to interfere with each other and outputs the interferometric light. In the present embodiment, the interferometer 70 is composed of a so-called Mach-Zehnder type interferometer, and has two optical paths 71 and 72 for providing an optical path length difference.
　［光検出部８０］
　光検出部８０は、干渉計７０から出射された干渉光を検出可能に構成されている。
本実施形態では、光検出部８０は、光電変換器８１と、増幅器８２と、ＡＤ変換器８３と、ＭＰＵ８４とを備える。 [Light detection unit 80]
The light detection unit 80 is configured to be able to detect the interference light emitted from the interferometer 70.
In the present embodiment, the photodetector 80 includes a photoelectric converter 81, an amplifier 82, an AD converter 83, and an MPU 84.
　光電変換器８１は、干渉計７０から出射された干渉光を入射して、電気信号に変換する。本実施形態では、第２ビームスプリッタ６２により分波された３つの干渉光に対応して、光電変換器８１が３つ設けられている。
　増幅器８２は、光電変換器８１にて変換された電気信号を増幅させる。本実施形態では、増幅器８２は、光電変換器８１に応じて３つ設けられている。
　ＡＤ変換器８３は、増幅器８２によって増幅された電気信号をデジタル信号に変換して、ＭＰＵ８４に入力させる。本実施形態では、ＡＤ変換器８３は、増幅器８２に応じて３つ設けられている。
　ＭＰＵ８４は、所謂Micro Processing Unitであり、ＡＤ変換器８３から出力されたデジタル信号に基づいて所定の演算を行うことにより、被測定物に作用する物理量を算出する。ＭＰＵ８４による物理量の算出方法については、後述する。なお、ＭＰＵ８４は、上記構成に限られるものではなく、例えば、ＣＰＵ（Central Processing Unit）から構成されていてもよい。 The photoelectric converter 81 incidents the interference light emitted from the interferometer 70 and converts it into an electric signal. In this embodiment, three photoelectric converters 81 are provided corresponding to the three interference lights demultiplexed by the second beam splitter 62.
The amplifier 82 amplifies the electric signal converted by the photoelectric converter 81. In this embodiment, three amplifiers 82 are provided according to the photoelectric converter 81.
The AD converter 83 converts the electric signal amplified by the amplifier 82 into a digital signal and causes the MPU 84 to input the electric signal. In this embodiment, three AD converters 83 are provided according to the amplifier 82.
The MPU 84 is a so-called Micro Processing Unit, and calculates a physical quantity acting on an object to be measured by performing a predetermined calculation based on a digital signal output from the AD converter 83. The method of calculating the physical quantity by the MPU 84 will be described later. The MPU 84 is not limited to the above configuration, and may be composed of, for example, a CPU (Central Processing Unit).
　［物理量の測定方法について］
　次に、被測定物に作用する物理量の測定方法について説明する。
　図２は、光学センサ５０から透過されるスペクトルと波長との関係を示す図であり、図３は、図２のスペクトルのピーク部を拡大した図であり、図４は、図２の３つのスペクトルを重ね合わせた図である。本実施形態では、波長可変光源１０が出射する光の波長を掃引することで、図２、３に示すような干渉光の波長スペクトル情報を得ることができる。なお、図２に示す３つの波長スペクトル情報は、それぞれ３つの増幅器８２によって増幅された電気信号に対応するものである。また、これらの３つの増幅器８２によって増幅された電気信号を重ね合わせることによって、図４に示すスペクトル情報を得ることができる。
　図４に示すように、光学センサ５０の測定用センサ素子５１から透過される透過光は、中心波長λ（λ＝１５５２ｎｍ付近）を透過率のピークとし、そのピーク値の短波長側と長波長側の両側に所定の波長帯域に渡り透過率がほぼ０となり、さらに、その波長帯域から短波長と長波長の両側にむけて透過率が上昇した後、減衰している。なお、光学センサ５０の上記中心波長λは例示であり、中心波長が上記と異なる光学センサ５０を用いてもよい。
　ここで、光電変換器８１で検出される光強度は、光学センサ５０の波長変化に伴い正弦波を描くことになる。この正弦波の位相変化Δφは数式（１）で示すことができる。 [How to measure physical quantities]
Next, a method for measuring the physical quantity acting on the object to be measured will be described.
FIG. 2 is a diagram showing the relationship between the spectrum transmitted from the optical sensor 50 and the wavelength, FIG. 3 is an enlarged view of the peak portion of the spectrum of FIG. 2, and FIG. It is the figure which superposed the spectrum. In the present embodiment, the wavelength spectrum information of the interference light as shown in FIGS. 2 and 3 can be obtained by sweeping the wavelength of the light emitted by the tunable light source 10. The three wavelength spectrum information shown in FIG. 2 correspond to the electric signals amplified by the three amplifiers 82, respectively. Further, the spectral information shown in FIG. 4 can be obtained by superimposing the electric signals amplified by these three amplifiers 82.
As shown in FIG. 4, the transmitted light transmitted from the measurement sensor element 51 of the optical sensor 50 has a center wavelength λ (around λ = 1552 nm) as a transmittance peak, and the short wavelength side and the long wavelength of the peak value. The transmittance is almost 0 over a predetermined wavelength band on both sides of the side, and further, the transmittance increases from that wavelength band toward both the short wavelength and the long wavelength, and then is attenuated. The center wavelength λ of the optical sensor 50 is an example, and an optical sensor 50 having a center wavelength different from the above may be used.
Here, the light intensity detected by the photoelectric converter 81 draws a sine wave as the wavelength of the optical sensor 50 changes. The phase change Δφ of this sine wave can be expressed by the mathematical formula (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　数式（１）において、λは光学センサ５０の波長、ｎｅは光ファイバのコアの実効屈折率、ｄは干渉計７０の２本の光路７１，７２の光路長の差、Δλは光学センサ５０の波長変化量である。
　この数式（１）からわかる通り、位相変化がわかれば、逆に波長変化量を計算することができる。位相変化の復調は、増幅器８２の出力電圧を用いて行われる。３つの増幅器８２の出力電圧Ｖｎは数式（２）で表すことができる。 In Equation (1), lambda is the wavelength of the optical sensor 50, n e is the effective refractive index of the core of the optical fiber, d represents the difference in optical path length of the two optical paths 71, 72 of the interferometer 70, [Delta] [lambda] is the optical sensor 50 It is the amount of change in wavelength of.
As can be seen from this mathematical formula (1), if the phase change is known, the amount of wavelength change can be calculated conversely. Demodulation of the phase change is performed using the output voltage of the amplifier 82. The output voltage V n of the three amplifiers 82 can be expressed by the mathematical formula (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　数式（２）では、αｎは光の経路損失や光電変換器８１の個体差等に起因する３つの増幅器８２それぞれの信号振幅を表す定数、Ｃは光電変換器８１の暗電流と増幅器８２のＤＣ成分とが合算された数値、ｎは３つの増幅器８２の番号を示し、ｎ＝１～３である。例えば、Ｖ１は３つの増幅器８２のうちの１番目の増幅器８２電圧値である。数式（３）を用いてこの３つの増幅器８２の出力から位相変化量を算出できる。ここで、αｎは光の過渡的な強度変化による外乱成分であり、数式（３）において、α２は２番目の増幅器８２から出力された信号に含まれる光の過渡的な強度変化による外乱成分であり、α３は３番目の増幅器８２から出力された信号に含まれる光の過渡的な強度変化による外乱成分である。通常、光の過渡的な強度変化はα２およびα３に共通して発生するために、単に定数の１を入れて演算を行う。これは、光源の光強度揺らぎ、経路中の光ファイバに加わる外乱因子（応力変動、温度変動）による光ファイバ損失変動によって変化する。 In equation (2), α n is a constant representing the signal amplitude of each of the three amplifiers 82 due to the path loss of light, individual differences of the photoelectric converter 81, etc., and C is the dark current of the photoelectric converter 81 and the amplifier 82. The value obtained by adding the DC components and n indicates the numbers of the three amplifiers 82, and n = 1 to 3. For example, V 1 is the voltage value of the first amplifier 82 of the three amplifiers 82. The amount of phase change can be calculated from the outputs of these three amplifiers 82 using the equation (3). Here, α n is a disturbance component due to a transient intensity change of light, and in equation (3), α 2 is a disturbance due to a transient intensity change of light contained in the signal output from the second amplifier 82. It is a component, and α 3 is a disturbance component due to a transient intensity change of light contained in the signal output from the third amplifier 82. Normally, the transient intensity change of light occurs in common with α 2 and α 3 , so the calculation is performed by simply inserting the constant 1. This changes due to fluctuations in the light intensity of the light source and fluctuations in the optical fiber loss due to disturbance factors (stress fluctuations, temperature fluctuations) applied to the optical fibers in the path.
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　したがって、ＭＰＵ８４で数式（３）の演算を行い、増幅器８２の３つの出力から位相変化量を算出し、続いて数式（１）の演算を行うことで、波長変化量を算出することができる。被測定物の物理量の変化の影響を受けるように取り付けられた光学センサ５０は、被測定物の物理量変化を出力するピーク波長の変化として出力する。この波長の変化量と物理量の変化量とは通常比例関係にあるため、物理量を求めることができる。 Therefore, the amount of change in wavelength can be calculated by performing the calculation of the formula (3) with the MPU 84, calculating the amount of phase change from the three outputs of the amplifier 82, and then performing the calculation of the formula (1). The optical sensor 50 mounted so as to be affected by the change in the physical quantity of the object to be measured outputs the change in the physical quantity of the object to be measured as a change in the peak wavelength. Since the amount of change in wavelength and the amount of change in physical quantity are usually in a proportional relationship, the physical quantity can be obtained.
　ここで、本実施形態では、図４に示すように、光学センサ５０は、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する。そのため、測定分解能を向上できる。
　さらに、スペクトルのうち光学センサ５０による信号以外の部分は、数式（４）に示すように、干渉計７０によって生じる三角関数状の波形となっている。そして、図２、３に示されるスペクトル情報から、カーブフィット等の手法を用いて干渉計７０の光路長差ｄを求めることができる。 Here, in the present embodiment, as shown in FIG. 4, the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved.
Further, the portion of the spectrum other than the signal obtained by the optical sensor 50 has a trigonometric waveform generated by the interferometer 70 as shown in the mathematical formula (4). Then, from the spectral information shown in FIGS. 2 and 3, the optical path length difference d of the interferometer 70 can be obtained by using a technique such as curve fitting.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　数式（４）で求めた干渉計７０の光路長差ｄと、数式(３)とを用いて、以下の数式（５）により、波長の絶対値情報λＣも算出することができる。 Using the optical path length difference d of the interferometer 70 obtained by the mathematical formula (4) and the mathematical formula (3), the absolute value information λ C of the wavelength can also be calculated by the following mathematical formula (5).
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　さらに、光の波長を掃引しながら光学センサ５０に入射させるので、干渉光を時間的に解析することにより、検出に不要な波長領域をカットすることができる。そのため、波長領域をカットするための光学機器、例えば、バンドパスフィルタを不要にできる。 Further, since the light wavelength is swept and incident on the optical sensor 50, the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
　［第１実施形態の効果］
　以上のような第１実施形態では、次の効果を奏することができる。
（１）本実施形態では、波長可変光源１０が出射する光の波長を掃引することで、干渉光の波長スペクトル情報を得ながら、干渉計７０の出力の位相情報を光学センサ５０の出力光強度を用いた解析により得ることができる。また、光学センサ５０は、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する。そのため、測定分解能を向上でき、かつ、光学センサ５０の出力波長の絶対値の情報を得ることができる。
　さらに、光の波長を変更しながら光学センサ５０に入射させるので、干渉光を時間的に解析することにより、検出に不要な波長領域をカットすることができる。そのため、波長領域をカットするための光学機器、例えば、バンドパスフィルタを不要にできる。 [Effect of the first embodiment]
In the first embodiment as described above, the following effects can be obtained.
(1) In the present embodiment, by sweeping the wavelength of the light emitted by the variable wavelength light source 10, the phase information of the output of the interferometer 70 is obtained from the output light intensity of the optical sensor 50 while obtaining the wavelength spectrum information of the interference light. It can be obtained by analysis using. Further, the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved, and information on the absolute value of the output wavelength of the optical sensor 50 can be obtained.
Further, since the light is incident on the optical sensor 50 while changing the wavelength of the light, the wavelength region unnecessary for detection can be cut by analyzing the interference light in time. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
（２）本実施形態では、光学センサ５０は、互いに近接配置された一対のファイバブラッググレーティングからファブリペローエタロンを構成する測定用センサ素子５１を有するので、測定用センサ素子５１から出射される光のスペクトルの半値全幅を小さくでき、測定分解能を向上させることができる。 (2) In the present embodiment, since the optical sensor 50 has a measurement sensor element 51 that constitutes a Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other, the light emitted from the measurement sensor element 51 The half-value full width of the spectrum can be reduced, and the measurement resolution can be improved.
　［第２実施形態］
　次に、本発明の第２実施形態の物理量測定装置１Ａについて図面に基づいて説明する。
　第２実施形態では、光学センサ５０Ａは、サーキュレータ２０Ａから入射した光を反射して、その反射光をサーキュレータ２０Ａに出力する測定用センサ素子５１Ａを有する点で第１実施形態と異なる。第２実施形態の説明において、第１実施形態の構成と同一のものは、同一符号を付して説明を省略する。 [Second Embodiment]
Next, the physical quantity measuring device 1A according to the second embodiment of the present invention will be described with reference to the drawings.
The second embodiment is different from the first embodiment in that the optical sensor 50A has a measurement sensor element 51A that reflects the light incident from the circulator 20A and outputs the reflected light to the circulator 20A. In the description of the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
　図５は、第２実施形態の物理量測定装置１Ａの概略構成を示す図である。
　図５に示すように、物理量測定装置１Ａは、波長可変光源１０と、サーキュレータ２０Ａと、光学センサ５０Ａと、ビームスプリッタ６０と、干渉計７０と、光検出部８０とを備える。 FIG. 5 is a diagram showing a schematic configuration of the physical quantity measuring device 1A of the second embodiment.
As shown in FIG. 5, the physical quantity measuring device 1A includes a wavelength variable light source 10, a circulator 20A, an optical sensor 50A, a beam splitter 60, an interferometer 70, and a light detection unit 80.
　［サーキュレータ２０Ａ］
　サーキュレータ２０Ａは、第１実施形態のサーキュレータ２０と同様に構成されている。そして、本実施形態では、サーキュレータ２０Ａは、波長可変光源１０から出射された光を入射して、光学センサ５０Ａに送る。さらに、サーキュレータ２０Ａは、光学センサ５０Ａから出力された反射光を入射して、ビームスプリッタ６０を介して干渉計７０に送る。
　なお、サーキュレータ２０Ａは、第１実施形態と同様に、例えば、ビームスプリッタから構成されていてもよい。 [Circulator 20A]
The circulator 20A is configured in the same manner as the circulator 20 of the first embodiment. Then, in the present embodiment, the circulator 20A incidents the light emitted from the tunable light source 10 and sends it to the optical sensor 50A. Further, the circulator 20A incidents the reflected light output from the optical sensor 50A and sends it to the interferometer 70 via the beam splitter 60.
The circulator 20A may be composed of, for example, a beam splitter as in the first embodiment.
　［光学センサ５０Ａ］
　光学センサ５０Ａは、前述した第１実施形態と同様に、図示略の被測定物に配置されており、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射可能に構成されている。本実施形態では、光学センサ５０Ａは、サーキュレータ２０Ａから出射された光を入射して、その反射光をサーキュレータ２０Ａに出力する測定用センサ素子５１Ａを有する。 [Optical sensor 50A]
The optical sensor 50A is arranged on the object to be measured (not shown) as in the first embodiment described above, and is configured to be capable of emitting output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. ing. In the present embodiment, the optical sensor 50A has a measurement sensor element 51A that incidents the light emitted from the circulator 20A and outputs the reflected light to the circulator 20A.
　測定用センサ素子５１Ａは、前述した第１実施形態と同様に、互いに近接配置された一対のファイバブラッググレーティングから構成され、ファブリペローエタロンを構成する。本実施形態では、前述したように、測定用センサ素子５１Ａは、反射光をサーキュレータ２０Ａに出力する。 The measurement sensor element 51A is composed of a pair of fiber Bragg gratings arranged close to each other, and constitutes a Fabry-Perot Etalon, as in the first embodiment described above. In the present embodiment, as described above, the measurement sensor element 51A outputs the reflected light to the circulator 20A.
　［物理量の測定方法について］
　次に、被測定物に作用する物理量の測定方法について説明する。
　図６は、光学センサ５０Ａから反射されるスペクトルと波長との関係を示す図であり、図７は、図６のスペクトルの一部を拡大した図であり、図８は、図６の３つのスペクトルを重ね合わせた図である。本実施形態では、前述した第１実施形態と同様に、波長可変光源１０が出射する光の波長を掃引することで、図６、７に示すような干渉光の波長スペクトル情報を得ることができる。なお、図６に示す３つの波長スペクトル情報は、それぞれ３つの増幅器８２によって増幅された電気信号に対応するものである。また、これらの３つの増幅器８２によって増幅された電気信号を重ね合わせることによって、図８に示すスペクトル情報を得ることができる。
　図８に示すように、光学センサ５０Ａの測定用センサ素子５１Ａから反射される反射光は、中心波長λ（λ＝１５５３ｎｍ付近）において反射率がほぼ０となり、その短波長側と長波長側の両側に所定の波長帯域に渡り反射率が０．７程度となり、さらに、その波長帯域から短波長と長波長の両側にむけて反射率が減衰している。つまり、前述した第１実施形態の透過光のスペクトルと、全く反対の傾向となっている。なお、光学センサ５０Ａの上記中心波長λは例示であり、中心波長が上記と異なる光学センサ５０Ａを用いてもよい。
　ここで、光電変換器８１で検出される反射光の強度Ｉｍは、ファブリペロー干渉によって切り取られるごく狭帯域の部分を除いて、数式（６）で示すことができる。 [How to measure physical quantities]
Next, a method for measuring the physical quantity acting on the object to be measured will be described.
FIG. 6 is a diagram showing the relationship between the spectrum reflected from the optical sensor 50A and the wavelength, FIG. 7 is an enlarged view of a part of the spectrum of FIG. 6, and FIG. It is the figure which superposed the spectrum. In the present embodiment, the wavelength spectrum information of the interference light as shown in FIGS. 6 and 7 can be obtained by sweeping the wavelength of the light emitted by the tunable light source 10 as in the first embodiment described above. .. The three wavelength spectrum information shown in FIG. 6 correspond to the electric signals amplified by the three amplifiers 82, respectively. Further, the spectral information shown in FIG. 8 can be obtained by superimposing the electric signals amplified by these three amplifiers 82.
As shown in FIG. 8, the reflected light reflected from the measurement sensor element 51A of the optical sensor 50A has a reflectance of almost 0 at the center wavelength λ (around λ = 1553 nm), and has a reflectance on the short wavelength side and the long wavelength side thereof. The reflectance is about 0.7 over a predetermined wavelength band on both sides, and the reflectance is further attenuated from that wavelength band toward both the short wavelength and the long wavelength. That is, the tendency is completely opposite to the spectrum of the transmitted light of the first embodiment described above. The center wavelength λ of the optical sensor 50A is an example, and an optical sensor 50A having a center wavelength different from the above may be used.
Here, the intensity I m of the reflected light detected by the photoelectric converter 81, except for the part of a very narrow band is cut by the Fabry-Perot interferometer, it can be represented by Equation (6).
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　数式（６）では、ｍは３つの光電変換器８１の番号を示し、ｍ＝１～３である。そして、図６、７に示されるスペクトル情報から、実際の光電変換器８１の実測信号Ｓｍに対して（Ｓｍ－Ｉｍ）２が最小となるようなカーブフィッティングを行うことにより、Ａｍ、ａ、ｂ、ｄを求めることができる。
　ここで、数式（７）に示すように、数式（６）で求めたＩｍから実測信号Ｓｍを差し引くことで、透過光を用いた上記第１実施形態と同様の意味を持つ出力電圧Ｖｎを算出することができる。 In the mathematical formula (6), m indicates the number of the three photoelectric converters 81, and m = 1 to 3. By performing the spectral information shown in FIGS. 6 and 7, the actual relative measured signal S m of the photoelectric converter 81 (S m -I m) curve fitting, such as 2 becomes minimum, A m , A, b, d can be obtained.
Here, as shown in Equation (7), by subtracting the measured signal S m from I m obtained in Equation (6), the output voltage V has a meaning similar to the first embodiment using the transmitted light n can be calculated.
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000007
　これにより、前述した第１実施形態と同様に、数式（３）を用いてこの３つの増幅器８２の出力から位相変化量を算出できる。
　したがって、ＭＰＵ８４で数式（３）の演算を行い、増幅器８２の３つの出力から位相変化量を算出し、続いて数式（１）の演算を行うことで、波長変化量を算出することができる。被測定物の物理量の変化の影響を受けるように取り付けられた光学センサ５０Ａは、被測定物の物理量変化を出力するピーク波長の変化として出力する。この波長の変化量と物理量の変化量とは通常比例関係にあるため、物理量を求めることができる。
　さらに、前述した第１実施形態と同様に、数式（５）により、波長の絶対値情報λＣも算出することができる。 As a result, the amount of phase change can be calculated from the outputs of the three amplifiers 82 using the mathematical formula (3) as in the first embodiment described above.
Therefore, the wavelength change amount can be calculated by performing the calculation of the formula (3) with the MPU 84, calculating the phase change amount from the three outputs of the amplifier 82, and then performing the calculation of the formula (1). The optical sensor 50A mounted so as to be affected by a change in the physical quantity of the object to be measured outputs the change in the physical quantity of the object to be measured as a change in peak wavelength. Since the amount of change in wavelength and the amount of change in physical quantity are usually in a proportional relationship, the physical quantity can be obtained.
Further, similarly to the first embodiment described above, the absolute value information λ C of the wavelength can also be calculated by the mathematical formula (5).
　［第２実施形態の効果］
　以上のような第２実施形態では、上記（１）、（２）と同様の効果を奏することができるほか、次の効果を奏することができる。
（３）本実施形態では、光学センサ５０Ａの反射光を、サーキュレータ２０Ａを介して干渉計７０に入射させる。そのため、光学センサの透過光を干渉計に入射させる場合に比べて、カプラやアイソレータを不要にでき、物理量測定装置１Ａの構成を簡素化することができる。 [Effect of the second embodiment]
In the second embodiment as described above, the same effects as those in (1) and (2) above can be obtained, and the following effects can be obtained.
(3) In the present embodiment, the reflected light of the optical sensor 50A is incident on the interferometer 70 via the circulator 20A. Therefore, as compared with the case where the transmitted light of the optical sensor is incident on the interferometer, the coupler and the isolator can be eliminated, and the configuration of the physical quantity measuring device 1A can be simplified.
　［第３実施形態］
　次に、本発明の第３実施形態の物理量測定装置１Ｂについて図面に基づいて説明する。
　第３実施形態では、光源として、広帯域光源１１が用いられ、干渉計７０の二次側に分光器９０が配置される点で第１、２実施形態と異なる。第３実施形態において、第１、２実施形態の構成と同一のものは、同一符号を付して説明を省略する。 [Third Embodiment]
Next, the physical quantity measuring device 1B according to the third embodiment of the present invention will be described with reference to the drawings.
The third embodiment is different from the first and second embodiments in that the wideband light source 11 is used as the light source and the spectroscope 90 is arranged on the secondary side of the interferometer 70. In the third embodiment, the same components as those in the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.
　図９は、第３実施形態の物理量測定装置１Ｂの概略構成を示す図である。
　図９に示すように、物理量測定装置１Ｂは、広帯域光源１１と、サーキュレータ２０と、カプラ３０と、アイソレータ４０と、光学センサ５０と、ビームスプリッタ６０と、干渉計７０と、分光器９０と、光検出部８０とを備える。 FIG. 9 is a diagram showing a schematic configuration of the physical quantity measuring device 1B of the third embodiment.
As shown in FIG. 9, the physical quantity measuring device 1B includes a broadband light source 11, a circulator 20, a coupler 30, an isolator 40, an optical sensor 50, a beam splitter 60, an interferometer 70, a spectroscope 90, and the like. It is provided with an optical detection unit 80.
　［広帯域光源１１］
　広帯域光源１１は、広帯域な波長の光を放出する光源である。広帯域光源１１は、例えば、ＳＣ（Super Continuum）光源であり、１２５０ｎｍ～１６５０ｎｍの波長領域の光を放出可能に構成されている。なお、広帯域光源１１は、上記構成に限られるものではなく、ＡＳＥ（Amplified Spontaneous Emission）光源やＳＬＤ（Super Luminescent Diode）光源等を組み合わせたものであってもよい。さらに、広帯域光源１１は、例示した波長領域よりも広い波長領域の光を放出可能に構成されていてもよく、あるいは、例示した波長領域よりも狭い波長領域の光を放出可能に構成されていてもよい。 [Wideband light source 11]
The wideband light source 11 is a light source that emits light having a wide band wavelength. The wideband light source 11 is, for example, an SC (Super Continuum) light source, and is configured to be capable of emitting light in a wavelength region of 1250 nm to 1650 nm. The broadband light source 11 is not limited to the above configuration, and may be a combination of an ASE (Amplified Spontaneous Emission) light source, an SLD (Super Luminescent Diode) light source, or the like. Further, the wideband light source 11 may be configured to be capable of emitting light in a wavelength region wider than the illustrated wavelength region, or may be configured to be capable of emitting light in a wavelength region narrower than the illustrated wavelength region. May be good.
　［分光器９０］
　分光器９０は、干渉計７０から出射された干渉光を入射して分光する。本実施形態では、第２ビームスプリッタ６２により分波された３つの干渉光に対応して、分光器９０が３つ設けられている。 [Spectroscope 90]
The spectroscope 90 injects and disperses the interference light emitted from the interferometer 70. In this embodiment, three spectroscopes 90 are provided corresponding to the three interference lights demultiplexed by the second beam splitter 62.
　［物理量の測定方法について］
　本実施形態では、前述した第１実施形態と同様に、光学センサ５０の透過光を干渉計７０にて干渉させた干渉光を解析することにより、被測定物に作用した物理量を測定する。この際、本実施形態では、前述した第１実施形態とは異なり、干渉光を分光器９０にて分光することにより、干渉光の波長スペクトル情報を得ることができる。そのため、前述した第１実施形態と同様に、光学センサ５０の出力波長の絶対値情報λＣを得ることができる。 [How to measure physical quantities]
In the present embodiment, similarly to the first embodiment described above, the physical quantity acting on the object to be measured is measured by analyzing the interference light in which the transmitted light of the optical sensor 50 is interfered with by the interference meter 70. At this time, in the present embodiment, unlike the first embodiment described above, the wavelength spectrum information of the interference light can be obtained by splitting the interference light with the spectroscope 90. Therefore, the absolute value information λ C of the output wavelength of the optical sensor 50 can be obtained as in the first embodiment described above.
　［第３実施形態の効果］
　以上のような第３実施形態では、上記（２）と同様の効果を奏することができるほか、次の効果を奏することができる。
（４）本実施形態では、干渉計７０から出射される干渉光を分光器９０にて分光することで、干渉光の波長スペクトル情報を得ながら、干渉計出力の位相情報を光学センサ５０の出力光強度を用いた解析により得ることができる。また、光学センサ５０は、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する。そのため、測定分解能を向上でき、かつ、光学センサ５０の出力波長の絶対値の情報を得ることができる。
　さらに、干渉光を分光して検出部に導入させるので、干渉光のスペクトルを解析することにより、検出に不要な波長領域をカットすることができる。そのため、波長領域をカットするための光学機器、例えば、バンドパスフィルタを不要にできる。 [Effect of Third Embodiment]
In the third embodiment as described above, in addition to being able to achieve the same effect as in (2) above, the following effects can be achieved.
(4) In the present embodiment, the interference light emitted from the interference meter 70 is separated by the spectroscope 90, so that the phase information of the interference meter output is output from the optical sensor 50 while obtaining the wavelength spectrum information of the interference light. It can be obtained by analysis using light intensity. Further, the optical sensor 50 emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured. Therefore, the measurement resolution can be improved, and information on the absolute value of the output wavelength of the optical sensor 50 can be obtained.
Further, since the interference light is separated and introduced into the detection unit, it is possible to cut a wavelength region unnecessary for detection by analyzing the spectrum of the interference light. Therefore, an optical device for cutting the wavelength region, for example, a bandpass filter can be eliminated.
　［第４実施形態］
　次に、本発明の第４実施形態の物理量測定装置１Ｃについて図面に基づいて説明する。
　第４実施形態では、光学センサ５０Ａは、サーキュレータ２０Ａから入射した光を反射して、その反射光をサーキュレータ２０Ａに出力する測定用センサ素子５１Ａを有する点で第３実施形態と異なる。第４実施形態の説明において、第１実施形態の構成と同一のものは、同一符号を付して説明を省略する。 [Fourth Embodiment]
Next, the physical quantity measuring device 1C according to the fourth embodiment of the present invention will be described with reference to the drawings.
The fourth embodiment is different from the third embodiment in that the optical sensor 50A has a measurement sensor element 51A that reflects the light incident from the circulator 20A and outputs the reflected light to the circulator 20A. In the description of the fourth embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
　図１０は、第４実施形態の物理量測定装置１Ｃの概略構成を示す図である。
　図１０に示すように、物理量測定装置１Ｃは、広帯域光源１１と、サーキュレータ２０Ａと、光学センサ５０Ａと、ビームスプリッタ６０と、干渉計７０と、分光器９０と、光検出部８０とを備える。 FIG. 10 is a diagram showing a schematic configuration of the physical quantity measuring device 1C of the fourth embodiment.
As shown in FIG. 10, the physical quantity measuring device 1C includes a broadband light source 11, a circulator 20A, an optical sensor 50A, a beam splitter 60, an interferometer 70, a spectroscope 90, and a light detection unit 80.
　［物理量の測定方法について］
　本実施形態では、前述した第２実施形態と同様に、光学センサ５０Ａの反射光を干渉計７０にて干渉させた干渉光を解析することにより、被測定物に作用した物理量を測定する。この際、本実施形態では、前述した第２実施形態とは異なり、干渉光を分光器９０にて分光することにより、干渉光の波長スペクトル情報を得ることができる。そのため、前述した第２実施形態と同様に、光学センサ５０Ａの出力波長の絶対値情報λＣを得ることができる。 [How to measure physical quantities]
In the present embodiment, similarly to the second embodiment described above, the physical quantity acting on the object to be measured is measured by analyzing the interference light in which the reflected light of the optical sensor 50A is interfered with by the interference meter 70. At this time, in the present embodiment, unlike the second embodiment described above, the wavelength spectrum information of the interference light can be obtained by splitting the interference light with the spectroscope 90. Therefore, the absolute value information λ C of the output wavelength of the optical sensor 50A can be obtained as in the second embodiment described above.
　［第４実施形態の効果］
　以上のような第３実施形態では、上記（２）～（４）と同様の効果を奏することができる。 [Effect of Fourth Embodiment]
In the third embodiment as described above, the same effects as those in (2) to (4) above can be obtained.
　［変形例］
　なお、本発明は前述の各実施形態に限定されるものではなく、本発明の目的を達成できる範囲での変形、改良等は本発明に含まれるものである。
　前述した第１～第４実施形態では、光学センサ５０，５０Ａは、互いに近接配置された一対のファイバブラッググレーティングからファブリペローエタロンを構成する測定用センサ素子５１，５１Ａを有して構成されていたが、これに限定されない。例えば、光学センサは、フィゾー干渉型の測定用センサ素子を有して構成されていてもよい。 [Modification example]
The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
In the first to fourth embodiments described above, the optical sensors 50 and 50A are configured to include measurement sensor elements 51 and 51A constituting Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other. However, it is not limited to this. For example, the optical sensor may be configured to include a Fizeau interference type measurement sensor element.
　前述した第１～第４実施形態では、干渉計７０は、マッハツェンダー型干渉計により構成されていたが、これに限定されない。例えば、干渉計は、マイケルソン型干渉計により構成されていてもよい。 In the first to fourth embodiments described above, the interferometer 70 was composed of a Mach-Zehnder type interferometer, but the present invention is not limited to this. For example, the interferometer may be composed of a Michaelson type interferometer.
　前述した第１～第４実施形態では、物理量測定装置１，１Ａ，１Ｂ，１Ｃには、光学センサ５０，５０Ａが１個設けられていたが、これに限定されない。例えば、物理量測定装置には、波長ピークの中心がそれぞれ異なる複数の光学センサが設けられていてもよい。
　この場合、複数の光学センサは、被測定物における同じ箇所に設けられていてもよい。このように構成することで、被測定物の同じ箇所において、例えば、圧力および温度といった異なる物理量の変化を正確に測定することができる。
　また、複数の光学センサは、被測定物における異なる箇所にそれぞれ設けられていてもよい。このように構成することで、被測定物の異なる位置での物理量の変化を正確に測定することができる。 In the first to fourth embodiments described above, the physical quantity measuring devices 1, 1A, 1B, and 1C are provided with one optical sensor 50, 50A, but the present invention is not limited to this. For example, the physical quantity measuring device may be provided with a plurality of optical sensors having different centers of wavelength peaks.
In this case, the plurality of optical sensors may be provided at the same location on the object to be measured. With this configuration, changes in different physical quantities such as pressure and temperature can be accurately measured at the same location of the object to be measured.
Further, the plurality of optical sensors may be provided at different locations on the object to be measured. With this configuration, changes in physical quantities at different positions of the object to be measured can be accurately measured.
　前述した第１、第３実施形態では、物理量測定装置１，１Ｃは、カプラ３０およびアイソレータ４０を備えて構成されていたが、これに限定されない。例えば、物理量測定装置１，１Ｃは、カプラ３０およびアイソレータ４０に代えてサーキュレータを備えて構成されていてもよい。 In the first and third embodiments described above, the physical quantity measuring devices 1 and 1C are configured to include the coupler 30 and the isolator 40, but the present invention is not limited thereto. For example, the physical quantity measuring devices 1 and 1C may be configured to include a circulator instead of the coupler 30 and the isolator 40.
　１，１Ａ，１Ｂ，１Ｃ…物理量測定装置、１０…波長可変光源、１１…広帯域光源、２０，２０Ａ…サーキュレータ、３０…カプラ，４０…アイソレータ，５０，５０Ａ…光学センサ、５１，５１Ａ…測定用センサ素子、６０…ビームスプリッタ、６１…第１ビームスプリッタ、６２…第２ビームスプリッタ、７０…干渉計、７１…光路、７２…光路、８０…光検出部、８１…光電変換器、８２…増幅器、８３…ＡＤ変換器、８４…ＭＰＵ、９０…分光器。 1,1A, 1B, 1C ... Physical quantity measuring device, 10 ... Variable wavelength light source, 11 ... Wideband light source, 20,20A ... Circulator, 30 ... Coupler, 40 ... Isolator, 50,50A ... Optical sensor, 51,51A ... For measurement Sensor element, 60 ... beam splitter, 61 ... first beam splitter, 62 ... second beam splitter, 70 ... interferometer, 71 ... optical path, 72 ... optical path, 80 ... optical detector, 81 ... photoelectric converter, 82 ... amplifier , 83 ... AD converter, 84 ... MPU, 90 ... spectroscope.

Claims (7)

  1. 　出射する光の波長を変更可能に構成された波長可変光源と、
    　前記波長可変光源から出射される前記光を入射して、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する光学センサと、
    　前記光学センサから出射された前記出力光を入射して、干渉光を出射する干渉計と、
    　前記干渉計から出射される前記干渉光を検出する光検出部と、を備える
    　ことを特徴とする物理量測定装置。     A tunable light source configured to change the wavelength of the emitted light,
    An optical sensor that incidents the light emitted from the wavelength variable light source and emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured.
    An interferometer that injects the output light emitted from the optical sensor and emits interference light,
    A physical quantity measuring device including a photodetector for detecting the interference light emitted from the interferometer.
  2. 　広帯域の光を出射する広帯域光源と、
    　前記広帯域光源から出射される前記光を入射して、被測定物に作用する物理量に応じて、半値全幅の小さい出力光を出射する光学センサと、
    　前記光学センサから出射された前記出力光を入射して、干渉光を出射する干渉計と、
    　前記干渉計から出射される前記干渉光を分光する分光器と、
    　前記分光器により分光された前記干渉光を検出する光検出部と、を備える
    　ことを特徴とする物理量測定装置。     A wideband light source that emits wideband light,
    An optical sensor that injects the light emitted from the wideband light source and emits output light having a small full width at half maximum according to the physical quantity acting on the object to be measured.
    An interferometer that injects the output light emitted from the optical sensor and emits interference light,
    A spectroscope that disperses the interferometric light emitted from the interferometer, and
    A physical quantity measuring device including a photodetector for detecting the interference light dispersed by the spectroscope.
  3. 　請求項１または請求項２に記載の物理量測定装置において、
    　前記光学センサは、互いに近接配置された一対のファイバブラッググレーティングからファブリペローエタロンを構成する測定用センサ素子を有する
    　ことを特徴とする物理量測定装置。     In the physical quantity measuring device according to claim 1 or 2.
    The optical sensor is a physical quantity measuring device including a measuring sensor element constituting a Fabry-Perot Etalon from a pair of fiber Bragg gratings arranged close to each other.
  4. 　請求項１または請求項２に記載の物理量測定装置において、
    　前記光学センサは、フィゾー干渉型の測定用センサ素子を有する
    　ことを特徴とする物理量測定装置。     In the physical quantity measuring device according to claim 1 or 2.
    The optical sensor is a physical quantity measuring device characterized by having a Fizeau interference type measuring sensor element.
  5. 　請求項１から請求項４のいずれか一項に記載の物理量測定装置において、
    　波長ピークの中心がそれぞれ異なる複数の前記光学センサが設けられる
    　ことを特徴とする物理量測定装置。     In the physical quantity measuring device according to any one of claims 1 to 4.
    A physical quantity measuring device characterized in that a plurality of the optical sensors having different centers of wavelength peaks are provided.
  6. 　請求項５に記載の物理量測定装置において、
    　複数の前記光学センサは、被測定物における同じ箇所に設けられる
    　ことを特徴とする物理量測定装置。     In the physical quantity measuring device according to claim 5.
    A physical quantity measuring device characterized in that a plurality of the optical sensors are provided at the same location on an object to be measured.
  7. 　請求項５に記載の物理量測定装置において、
    　複数の前記光学センサは、被測定物における異なる箇所にそれぞれ設けられる
    　ことを特徴とする物理量測定装置。     In the physical quantity measuring device according to claim 5.
    A physical quantity measuring device characterized in that a plurality of the optical sensors are provided at different locations on an object to be measured.
PCT/JP2021/005422 2020-03-27 2021-02-15 Physical quantity measurement device WO2021192717A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020058244A JP2021156771A (en) 2020-03-27 2020-03-27 Physical quantity measurement device
JP2020-058244 2020-03-27

Publications (1)

Publication Number Publication Date
WO2021192717A1 true WO2021192717A1 (en) 2021-09-30

Family

ID=77891195

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/005422 WO2021192717A1 (en) 2020-03-27 2021-02-15 Physical quantity measurement device

Country Status (2)

Country Link
JP (1) JP2021156771A (en)
WO (1) WO2021192717A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004163155A (en) * 2002-11-11 2004-06-10 Fuji Electric Systems Co Ltd Wavelength-measuring apparatus
JP2006003197A (en) * 2004-06-17 2006-01-05 Hitachi Cable Ltd Optical cable for fbg sensor
US20100085572A1 (en) * 2008-10-06 2010-04-08 Schlumberger Technology Corporation Time domain multiplexing of interferometric sensors
JP2011149875A (en) * 2010-01-22 2011-08-04 Institute Of National Colleges Of Technology Japan Wavelength detection type optical fiber sensor system
JP2013148475A (en) * 2012-01-19 2013-08-01 Nagano Keiki Co Ltd Physical quantity measurement device and physical quantity measurement method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004163155A (en) * 2002-11-11 2004-06-10 Fuji Electric Systems Co Ltd Wavelength-measuring apparatus
JP2006003197A (en) * 2004-06-17 2006-01-05 Hitachi Cable Ltd Optical cable for fbg sensor
US20100085572A1 (en) * 2008-10-06 2010-04-08 Schlumberger Technology Corporation Time domain multiplexing of interferometric sensors
JP2011149875A (en) * 2010-01-22 2011-08-04 Institute Of National Colleges Of Technology Japan Wavelength detection type optical fiber sensor system
JP2013148475A (en) * 2012-01-19 2013-08-01 Nagano Keiki Co Ltd Physical quantity measurement device and physical quantity measurement method

Also Published As

Publication number Publication date
JP2021156771A (en) 2021-10-07

Similar Documents

Publication Publication Date Title
US6525308B1 (en) Apparatus and method for wavelength detection with fiber bragg grating sensors
US6137565A (en) Bragg grating temperature/strain fiber sensor having combination interferometer/spectrometer output arrangement
US6888125B2 (en) Fiber optic sensing systems and method of use thereof
US7324714B1 (en) Multicore fiber curvature sensor
EP2839554B1 (en) Frequency tunable laser system
JP5322238B2 (en) Physical quantity measuring device
US20080204759A1 (en) Method for demodulating signals from a dispersive white light interferometric sensor and its application to remote optical sensing
Lee et al. Interrogation techniques for fiber grating sensors and the theory of fiber gratings
JP6290798B2 (en) OFDR device
EP3710787B1 (en) A fibre optic sensing device
Lo In-fiber Bragg grating sensors using interferometric interrogations for passive quadrature signal processing
KR100275521B1 (en) Optical signal wavelength measurement device and optical fiber Bragg grating sensor device and method using wavelength selective photodetector
WO2021192717A1 (en) Physical quantity measurement device
JP2014149190A (en) Measuring device, measuring method, light source device, and article manufacturing method
US5333045A (en) Process and apparatus for absolute interferometric measurement of physical magnitudes utilizing a variable center frequency pass-band filter located downstream of a light beam source
Hlubina Measuring a spectral bandpass of a fibre-optic spectrometer using time-domain and spectral-domain two-beam interference
WO2020213466A1 (en) Physical quantity measurement device
CN115031824B (en) Low noise white light PMDI signal detection and multiplexing system and method
JP2002116087A (en) Wavelength-measuring apparatus
US20220326069A1 (en) Demodulation Of Fiber Optic Sensors
Poiana et al. Compact system of dispersion spectroscopy for interrogating fiber Bragg grating sensors using multi-wavelength phase shift interferometry
JP2004163154A (en) Wavelength-measuring apparatus
JP2010096597A (en) Optical sensor measuring device and optical sensor measuring method
JP3632825B2 (en) Wavelength measuring device
JP2021043050A (en) Optical sensor and physical amount measurement device

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: 21777143

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21777143

Country of ref document: EP

Kind code of ref document: A1