WO2020194856A1 - Capteur cohérent optique et procédé de détection cohérente optique - Google Patents

Capteur cohérent optique et procédé de détection cohérente optique Download PDF

Info

Publication number
WO2020194856A1
WO2020194856A1 PCT/JP2019/045776 JP2019045776W WO2020194856A1 WO 2020194856 A1 WO2020194856 A1 WO 2020194856A1 JP 2019045776 W JP2019045776 W JP 2019045776W WO 2020194856 A1 WO2020194856 A1 WO 2020194856A1
Authority
WO
WIPO (PCT)
Prior art keywords
time
light
optical
respect
phase
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/JP2019/045776
Other languages
English (en)
Japanese (ja)
Inventor
直毅 山城
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oki Electric Industry Co Ltd
Original Assignee
Oki Electric Industry Co Ltd
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 Oki Electric Industry Co Ltd filed Critical Oki Electric Industry Co Ltd
Publication of WO2020194856A1 publication Critical patent/WO2020194856A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for

Definitions

  • the present invention relates to, for example, an optical coherent sensor and an optical coherent sensing method applicable to a distributed vibration sensor using an optical fiber.
  • This OTDR is also applied to optical sensors such as distributed measurement of vibration transmitted to optical fibers.
  • vibration When vibration is applied to the optical fiber, the phase of the backscattered light generated near the position where the vibration is applied changes. Therefore, by observing the phase change of the backscattered light obtained by the OTDR, it is possible to obtain information on the vibration applied to the optical fiber in a distributed manner.
  • a distributed vibration sensor DAS: Distributed Vibration Sensor
  • DAS Distributed Acoustic Sensor
  • the phase of the backscattered light changes due to the vibration applied to the optical fiber from the outside, but it also depends on the phase of the probe light.
  • the phase of the probe light changes due to the vibration received before reaching the backscattered light generation position (observation point). Therefore, in order to measure the vibration at each position, a means for measuring the phase difference of the backscattered light generated at two different points on the optical fiber is usually adopted. Generally, the distance between these two points is called the gauge length.
  • a vibration waveform can be obtained from the obtained time change of the phase difference.
  • the OTDR waveform obtained by using a high coherence laser as a light source of probe light is obtained as a result of interference of backward scattered light from a plurality of scattering centers generated during the propagation of an optical pulse. Therefore, the intensity of the backscattered light varies irregularly with respect to the generation position. This phenomenon is called fading and affects the vibration measurement results.
  • the present invention has been made in view of the above-mentioned problems, and an object of the present invention is an optical coherent sensor and an optical sensor that avoids deterioration of accuracy due to fading by signal processing without introducing an expensive device.
  • the purpose is to provide a coherent sensing method.
  • the optical coherent sensor of the present invention coherently detects a light source unit that generates an optical pulse as probe light and a signal light generated by a measurement object by the probe light to generate a beat signal. It is configured to include a light receiving unit and a calculation unit into which a beat signal is input.
  • the calculation unit includes optical information acquisition means, accuracy deterioration avoidance means, and phase difference information acquisition means.
  • the optical information acquisition means acquires the distribution of the intensity I (tj) and the phase P (tj) of the signal light from the beat signal with respect to the reception time tj of the signal light for each optical pulse.
  • the accuracy deterioration avoiding means sets the reference time ST.
  • the phase difference information acquisition means determines the phase difference of the signal light with respect to the light receiving time tj, the difference between the phase P (tk) with respect to the light receiving time tk and the phase P (ti) with respect to the light receiving time ti, P (tk) ⁇ P (ti). And the distribution of the phase difference with respect to the reception time of the signal light is acquired.
  • the difference between tk and ti is the reference time ST.
  • the accuracy deterioration avoiding means changes the first time ⁇ t1 with respect to the reference time ST0 in the initial state, and a plurality of lights for each first time ⁇ t1.
  • the minimum value of the intensity I (tk + ⁇ t1) in the pulse is acquired, and the maximum first time ⁇ t1max at which this minimum value is maximum is acquired.
  • the second time ⁇ t2 is changed with respect to the reference time ST0 in the initial state, and the minimum value of the intensity I (ti ⁇ t2) in each of a plurality of optical pulses is obtained for each second time ⁇ t2, and this minimum value is obtained.
  • the maximum second time ⁇ t2max at which the value becomes the maximum is acquired. After that, ST0 + ⁇ t1max + ⁇ t2max is set as the reference time ST.
  • the optical coherent sensing method of the present invention is configured to include the following processes. First, an optical pulse is generated as probe light. Next, the signal light generated in the object to be measured by the probe light is coherently detected to generate a beat signal. Next, for each optical pulse, the distribution of the intensity I (tj) and the phase P (tj) of the signal light with respect to the light reception time tj of the signal light is acquired from the beat signal. Next, the reference time ST is set. Next, the phase difference of the signal light with respect to the light receiving time tj is acquired as the difference between the phase P (tk) with respect to the light receiving time tk and the phase P (ti) with respect to the light receiving time ti, P (tk) ⁇ P (ti). Acquire the distribution of the phase difference with respect to the reception time of the signal light.
  • the first time ⁇ t1 is changed with respect to the reference time ST0 in the initial state, and each first time ⁇ t1
  • the minimum value of the intensity I (tk + ⁇ t1) in each of the plurality of optical pulses is acquired, and the maximum first time ⁇ t1max at which this minimum value is maximum is acquired.
  • the second time ⁇ t2 is changed with respect to the reference time ST0 in the initial state, and the minimum value of the intensity I (ti ⁇ t2) in each of a plurality of optical pulses is obtained for each second time ⁇ t2, and this minimum value is obtained.
  • the maximum second time ⁇ t2max at which the value becomes the maximum is acquired.
  • ST0 + ⁇ t1max + ⁇ t2max is set as the reference time ST.
  • the optical coherent sensor and the optical coherent sensing method of the present invention in obtaining the phase difference, the first time ⁇ t1 and the second time ⁇ t2 are changed so that the intensity I of the signal light from the two points becomes large.
  • the reference time ST By setting the reference time ST, it is possible to avoid deterioration of accuracy due to fading.
  • FIG. 1 is a schematic diagram for explaining the optical coherent sensor of the present invention.
  • a vibration detection optical fiber sensor will be described as a configuration example of the optical coherent sensor.
  • the vibration detection optical fiber sensor includes a light source unit 10, an optical circulator 20, an optical fiber 30, a light receiving unit 50, and a calculation unit 60. This vibration detection optical fiber sensor is used for OTDR.
  • the light source unit 10 periodically generates an optical pulse as probe light. That is, the light source unit 10 generates an optical pulse train.
  • the spatial resolution of the vibration detection optical fiber sensor depends on the width of this optical pulse. Further, the measurement distance of the vibration detection optical fiber sensor depends on the repetition frequency of the optical pulse. It takes 5 ns for the optical pulse to propagate 1 m through the optical fiber 30 which is the object to be measured. When observing the backscattered light generated by the optical fiber 30 as the signal light, it takes a round trip time of the forward propagation and the reverse propagation, so that a delay of 10 ns per 1 m occurs. For example, when the pulse width is 100 ns and the repetition frequency is 5 kHz, the spatial resolution is 10 m and the maximum measurement distance is 20 km.
  • the light source unit 10 includes, for example, a laser light source 12, a fiber coupler 13, an intensity modulator 14, a function generator 16, and an optical amplifier 18.
  • the laser light source 12 generates laser light as continuous light in the communication wavelength band.
  • the laser light source 12 it is preferable to use a so-called narrow line width laser having a line width of 10 kHz or less.
  • this vibration detection optical fiber sensor can be used for a phase sensitive OTDR.
  • the wavelength of the laser beam may be arbitrary, but it is preferable to use a standard single-mode optical fiber with a low loss of 1550 nm.
  • the laser beam generated by the laser light source 12 is sent to the fiber coupler 13.
  • the fiber coupler 13 splits the laser beam into two. One of the two branches is sent to the intensity modulator 14. The other bifurcated light is sent to the light receiving unit 50 as reference light.
  • the function generator 16 generates a rectangular electric pulse. This electric pulse is sent to the intensity modulator 14.
  • the electric pulse generated by the function generator 16 has, for example, a pulse width of 100 ns width and a repetition frequency of 5 kHz.
  • the output of the function generator 16 is also sent to the analog-to-digital (A / D) converter 56, which will be described later, and is used as a trigger signal.
  • the intensity modulator 14 converts the laser beam into an optical pulse with an electric pulse to generate an optical pulse.
  • This optical pulse is sent to the optical amplifier 18.
  • the pulse width and repetition frequency of the optical pulse generated by the intensity modulator 14 are both the same as the electric pulse generated by the function generator 16.
  • the optical pulse has a pulse width of 100 ns and a repetition frequency of 5 kHz.
  • an acousto-optic modulator (AOM: Acoustic Modulator) is used.
  • AOM Acoustic Modulator
  • the frequency of the optical pulse generated by the intensity modulator 14 changes from the frequency of the laser beam input to the intensity modulator 14 due to the optical Doppler effect. For this reason, heterodyne detection is often performed during coherent detection by the light receiving unit 50.
  • the optical pulse generated by the intensity modulator 14 receives a predetermined amplification by the optical amplifier 18. This is because the stronger the intensity of the optical pulse, the stronger the intensity of the backscattered light in the optical fiber 30.
  • the optical pulse amplified by the optical amplifier 18 is sent to the optical fiber 30 as probe light via the optical circulator 20. Although illustration and description are omitted here, a bandpass filter (BPF) is generally used after the optical amplifier 18.
  • BPF removes noise of spontaneous emission light (ASE: Amplified Spontaneous Emission) generated by the optical amplifier 18.
  • the probe light sent to the optical fiber 30 propagates through the optical fiber 30, and backscattered light is generated along with the propagation of the probe light.
  • This backscattered light is sent to the light receiving unit 50 as signal light via the optical circulator 20.
  • an optical amplifier and a BPF are often provided in front of the light receiving unit 50 in order to amplify the backscattered light.
  • the light receiving unit 50 coherently detects the backscattered light generated in the optical fiber 30 by the probe light and generates an electric signal.
  • the light receiving unit 50 includes a coherent receiver 52, a balanced photodiode (PD) 54, and an analog-to-digital (A / D) converter 56.
  • the coherent receiver 52 uses the reference light to perform coherent detection of backscattered light.
  • the coherent receiver 52 for example, an optical 90 ° hybrid coupler can be used.
  • the output from the coherent receiver 52 is sent to the balanced PD 54.
  • the balanced PD54 balance-detects the output from the coherent receiver 52.
  • I-phase (cos wave) and Q-phase (sine wave) beat signals having information on the intensity and phase of backscattered light are generated.
  • the I-phase and Q-phase beat signals are sent to the A / D converter 56.
  • the A / D converter 56 converts the I-phase and Q-phase beat signals into digital signals.
  • the I-phase and Q-phase beat signals converted into digital signals are input to the arithmetic unit 60.
  • the arithmetic unit 60 for example, a commercially available personal computer (PC) can be used.
  • the arithmetic unit 60 will be described as being configured to include a CPU (Central Processing Unit) 70, a RAM (Random Access Memory) 62, a ROM (Read Only Memory) 64, and a storage means 66.
  • the CPU 70 realizes each functional means described later by executing a program stored in the ROM 64.
  • the processing result of each functional means is temporarily stored in the RAM 62.
  • Functional means included in the calculation unit 60 includes optical information acquisition means 72, phase difference information acquisition means 74, and accuracy deterioration avoidance means 76.
  • the optical information acquisition means 72 sends the distribution of the intensity I (t) and the phase P (t) of the backscattered light with respect to the light receiving time t of the backscattered light from the A / D converter 56 for each light pulse. Obtained from the beat signal.
  • the optical information acquisition means 72 In acquiring the intensity I (t) and the phase P (t), the optical information acquisition means 72 first generates a complex amplitude of backscattered light from the beat signals of the I phase and the Q phase.
  • the complex amplitude of this backscattered light is also a beat signal, it is necessary to down-convert it. Therefore, next, the complex amplitude of the backscattered light is down-converted.
  • a method of this down-conversion for example, a method of integrating the complex amplitude of reverse rotation having a beat frequency with the complex amplitude of backscattered light and operating a low-pass filter (LPF) is used.
  • LPF low-pass filter
  • the distribution of the intensity I (t) of the backscattered light with respect to the reception time t of the backscattered light can be obtained.
  • the distribution of the phase P (t) of the backscattered light can also be obtained by calculating the phase of the complex amplitude.
  • the distribution of the intensity I (t) and the phase P (t) is stored in the storage means 66.
  • the storage means 66 stores the distribution of the intensity I (t) and the phase P (t) for a number of optical pulses determined according to the capacitance of the storage means 66.
  • the phase difference information acquisition means 74 sets the phase difference ⁇ P (tj) of the backward scattered light with respect to the light receiving time tj, the phase P (tk) with respect to the light receiving time tk, and the phase P (ti) with respect to the light receiving time ti. )
  • the difference P (tk) ⁇ P (ti) and the distribution of the phase difference ⁇ P (tj) with respect to the reception time tj of the signal light is acquired.
  • the difference between tk and ti is the reference time ST.
  • the phase difference information acquisition means 74 acquires vibration information at each position of the optical fiber 30 from the distribution of the phase difference ⁇ P (x) by any suitable conventionally known method.
  • the accuracy deterioration avoiding means 76 sets the reference time ST, and sends the set reference time ST to the phase difference information acquisition means 74.
  • the accuracy deterioration avoiding means 76 acquires the minimum value min ( ⁇ t1) of the intensity I (tk + ⁇ t1) in the plurality of optical pulses stored in the storage means 66 with respect to the reference time ST0 in the initial state and the first time ⁇ t1. To do. Further, by changing the first time ⁇ t1, among the minimum values min ( ⁇ t1) obtained for each first time ⁇ t1, the first time ⁇ t1 at which the minimum value min ( ⁇ t1) is the maximum is set to the maximum first time ⁇ t1max. Get as.
  • the accuracy deterioration avoiding means 76 has a minimum value min (ti ⁇ t2) of the intensity I (ti ⁇ t2) in a plurality of optical pulses stored in the storage means 66 with respect to the reference time ST0 in the initial state and the second time ⁇ t2. ⁇ t2) is acquired. Further, by changing the second time ⁇ t2, among the minimum values min ( ⁇ t2) obtained for each second time ⁇ t2, the second time ⁇ t2 at which the minimum value min ( ⁇ t2) is the maximum is set to the maximum second time ⁇ t2max. Get as.
  • the variable width of the first time ⁇ t1 and the second time ⁇ t2, that is, the variable width of the reference time ST can be set arbitrarily and preferably. For example, when the reference time ST is increased, the ability to avoid accuracy deterioration due to fading increases, but the spatial resolution decreases. On the other hand, when the reference time ST is reduced, the degree of increase in the ability to avoid accuracy deterioration due to fading is not large, but the decrease in spatial resolution can be suppressed. In the characteristic test described later, it is shown that the influence of accuracy deterioration can be reduced by making the reference time ST variable in the range of, for example, about ST0 to ST0 + ST0 / 2.
  • the accuracy deterioration avoiding means 76 has a gauge length GL0 in the initial state and a minimum value min (d1) of the intensity I (xk + d1) in a plurality of optical pulses stored in the storage means 66 with respect to the first distance d1. ) To get. Further, by changing the first distance d1, among the minimum values min (d1) obtained for each first distance d1, the first distance d1 at which the minimum value min (d1) is the maximum is set to the maximum first distance d1max. Get as.
  • the accuracy deterioration avoiding means 76 has a gauge length GL0 in the initial state and a minimum value min of the intensity I (xi ⁇ d2) in a plurality of optical pulses stored in the storage means 66 with respect to the second distance d2. Acquire d2). Further, by changing the second distance d2, among the minimum values min (d2) obtained for each second distance d2, the second distance d2 at which the minimum value min (d2) is the maximum is set to the maximum second distance d2max. Get as.
  • GL0 + d1max + d2max is set as the gauge length GL.
  • the variable width of the first distance d1 and the second distance d2, that is, the variable width of the gauge length GL can be set arbitrarily and preferably.
  • the gauge length GL may be made variable in the range of, for example, about GL0 to GL0 + GL0 / 2.
  • FIG. 2 is a diagram showing the results of a characteristic test of a vibration detection optical fiber sensor.
  • FIG. 2 (A) shows the result when the gauge length GL is fixed (comparative example)
  • FIG. 2 (B) shows the result when the gauge length GL is adapted (example).
  • the horizontal axis represents the distance [km] from the input end of the optical fiber
  • the vertical axis represents the time [ms].
  • the shading indicates the phase.
  • the length of the optical fiber 30 is set to 12 km.
  • a fiber stretcher was used to vibrate the optical fiber 30 over a length of 40 m.
  • the laser light source 12 a narrow line width laser having a line width of 3 kHz is used.
  • FIG. 2 (A) shows the result when the gauge length GL is fixed at 80 m. At a position 1 km from the input end of the optical fiber 30, the phase change due to the applied vibration can be confirmed. In FIG. 2A, a large phase change is observed near the position of 2.5 km, 2.8 km, and 4.8 km from the input end of the optical fiber 30. These phase changes are not due to the applied vibration, but due to the deterioration of accuracy due to fading.
  • FIG. 2B shows the result when the gauge length GL is changed within the range of 80 m to 120 m.
  • the phase change due to the applied vibration can be confirmed.
  • no large phase change was observed in the vicinity of the positions 2.5 km, 2.8 km, and 4.8 km from the input end of the optical fiber 30 seen in FIG. 2 (A). That is, it can be seen that the accuracy deterioration due to fading can be reduced by making the gauge length GL variable.
  • an optical coherent sensor capable of reducing accuracy deterioration due to fading has been described by taking a vibration detection optical fiber sensor as an example, but the present invention is not limited to this.
  • the present invention can be applied to any optical coherent sensor that utilizes the phase difference between two points.
  • the homodyne detection may be used.
  • an intensity modulator 16 having no frequency shift may be used, or a frequency shifter that shifts the frequency of the reference light between the fiber coupler 14 and the coherent receiver 52 may be used.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

Sans incorporer un dispositif coûteux, la présente invention utilise un traitement de signal pour empêcher un évanouissement de provoquer une dégradation de précision. La présente invention comprend : une unité de source de lumière qui produit des impulsions optiques en tant que lumière de sonde, une unité de réception de lumière qui produit un signal de battement par détection cohérente de la lumière de signal produite par un objet de mesure en résultat de la lumière de sonde, et une unité de calcul qui reçoit le signal de battement. L'unité de calcul comprend des moyens d'acquisition d'informations de lumière, des moyens de prévention de dégradation de précision et des moyens d'acquisition d'informations de différence de phase. Pour chaque impulsion optique, les moyens d'acquisition d'informations de lumière acquièrent, à partir du signal de battement, la distribution de l'intensité I(tj) et la phase P(tj) de la lumière de signal par rapport au temps de réception de lumière tj de la lumière de signal. Les moyens de prévention de dégradation de précision règlent un temps de référence ST Les moyens d'acquisition d'informations de différence de phase acquièrent une différence de phase pour le temps de réception de lumière tj de la lumière de signal en tant que différence de phase P(tk) - P(ti) entre le temps tk de réception de lumière, où tk > ti et la différence entre tk et ti est le temps de référence ST, et le temps de réception de lumière ti et acquièrent la distribution de la différence de phase par rapport au temps de réception de lumière de la lumière de signal.
PCT/JP2019/045776 2019-03-27 2019-11-22 Capteur cohérent optique et procédé de détection cohérente optique Ceased WO2020194856A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-060661 2019-03-27
JP2019060661A JP7156132B2 (ja) 2019-03-27 2019-03-27 光コヒーレントセンサ及び光コヒーレントセンシング方法

Publications (1)

Publication Number Publication Date
WO2020194856A1 true WO2020194856A1 (fr) 2020-10-01

Family

ID=72611319

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2019/045776 Ceased WO2020194856A1 (fr) 2019-03-27 2019-11-22 Capteur cohérent optique et procédé de détection cohérente optique

Country Status (2)

Country Link
JP (1) JP7156132B2 (fr)
WO (1) WO2020194856A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023053263A1 (fr) * 2021-09-29 2023-04-06 日本電信電話株式会社 Procédé et dispositif de test d'impulsion optique
JP2025517778A (ja) * 2022-05-19 2025-06-10 エヌイーシー ラボラトリーズ アメリカ インク コヒーレントｏｔｄｒを使用した自動ファイバ損失検出

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7298471B2 (ja) * 2019-12-25 2023-06-27 沖電気工業株式会社 光コヒーレントセンサ及び光コヒーレントセンシング方法
JP2024017862A (ja) * 2022-07-28 2024-02-08 沖電気工業株式会社 光ファイバセンサ及び光ファイバセンシング方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002267537A (ja) * 2001-03-12 2002-09-18 Hitachi Cable Ltd 回折格子反射波長計測方法及びその装置並びに物理量計測方法及びその装置
JP2007086008A (ja) * 2005-09-26 2007-04-05 Nippon Telegr & Teleph Corp <Ntt> 分岐を有する光ファイバの試験方法及び装置
JP2010175502A (ja) * 2009-02-02 2010-08-12 Sumitomo Electric Ind Ltd 光線路監視装置および光線路監視システム
JP2011038839A (ja) * 2009-08-07 2011-02-24 Nippon Telegr & Teleph Corp <Ntt> 光周波数領域反射測定方法及び光周波数領域反射測定装置
JP2011164075A (ja) * 2010-02-15 2011-08-25 Nippon Telegr & Teleph Corp <Ntt> 光パルス試験方法及び光パルス試験装置
JP2017044504A (ja) * 2015-08-24 2017-03-02 沖電気工業株式会社 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
JP2018048917A (ja) * 2016-09-21 2018-03-29 日本電信電話株式会社 光ファイバ試験装置及び光ファイバ試験方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002267537A (ja) * 2001-03-12 2002-09-18 Hitachi Cable Ltd 回折格子反射波長計測方法及びその装置並びに物理量計測方法及びその装置
JP2007086008A (ja) * 2005-09-26 2007-04-05 Nippon Telegr & Teleph Corp <Ntt> 分岐を有する光ファイバの試験方法及び装置
JP2010175502A (ja) * 2009-02-02 2010-08-12 Sumitomo Electric Ind Ltd 光線路監視装置および光線路監視システム
JP2011038839A (ja) * 2009-08-07 2011-02-24 Nippon Telegr & Teleph Corp <Ntt> 光周波数領域反射測定方法及び光周波数領域反射測定装置
JP2011164075A (ja) * 2010-02-15 2011-08-25 Nippon Telegr & Teleph Corp <Ntt> 光パルス試験方法及び光パルス試験装置
JP2017044504A (ja) * 2015-08-24 2017-03-02 沖電気工業株式会社 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
JP2018048917A (ja) * 2016-09-21 2018-03-29 日本電信電話株式会社 光ファイバ試験装置及び光ファイバ試験方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023053263A1 (fr) * 2021-09-29 2023-04-06 日本電信電話株式会社 Procédé et dispositif de test d'impulsion optique
JPWO2023053263A1 (fr) * 2021-09-29 2023-04-06
JP7586337B2 (ja) 2021-09-29 2024-11-19 日本電信電話株式会社 光パルス試験方法及び光パルス試験装置
JP2025517778A (ja) * 2022-05-19 2025-06-10 エヌイーシー ラボラトリーズ アメリカ インク コヒーレントｏｔｄｒを使用した自動ファイバ損失検出

Also Published As

Publication number Publication date
JP2020159915A (ja) 2020-10-01
JP7156132B2 (ja) 2022-10-19

Similar Documents

Publication Publication Date Title
JP6308160B2 (ja) 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
JP6358277B2 (ja) 光ファイバ歪み及び温度測定装置並びに光ファイバ歪み及び温度測定方法
US20140268110A1 (en) Measuring brillouin backscatter from an optical fibre using digitisation
JP2018054551A (ja) 光ファイバ歪み及び温度測定装置
US9784567B2 (en) Distributed brillouin sensing using correlation
WO2020194856A1 (fr) Capteur cohérent optique et procédé de détection cohérente optique
JP7286994B2 (ja) 光ファイバ歪み及び温度測定装置並びに光ファイバ歪み及び温度測定方法
CN101410696A (zh) 干扰位置的估计
JP6308184B2 (ja) 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
JP6308183B2 (ja) 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
CN108827447B (zh) 一种异频双脉冲cotdr传感装置和方法
JP2019060743A (ja) 光ファイバ歪み及び温度測定装置並びに光ファイバ歪み及び温度測定方法
KR20180010049A (ko) 유효 측정점 개수가 확대된 공간선택적 브릴루앙 분포형 광섬유 센서 및 브릴루앙 산란을 이용한 센싱 방법
JPWO2020084825A1 (ja) 光パルス試験装置及び光パルス試験方法
JP7040386B2 (ja) 光ファイバ歪み及び温度測定装置並びに光ファイバ歪み及び温度測定方法
KR102875025B1 (ko) 분포형 음향 센서에서 진동 신호 추출을 위한 위상 검출기 및 위상 검출 방법
WO2022259437A1 (fr) Dispositif et procédé de mesure de vibrations
JP2022040695A (ja) 光ファイバ歪み測定装置及びブリルアン周波数シフトオフセットの調整方法
JP7396382B2 (ja) 光ファイバセンサ及びブリルアン周波数シフト測定方法
JP7424250B2 (ja) 光ファイバ歪測定装置及び光ファイバ歪測定方法
JP7298471B2 (ja) 光コヒーレントセンサ及び光コヒーレントセンシング方法
US12270688B2 (en) Optical fiber sensor and Brillouin frequency shift measurement method
CN116707628A (zh) 一种传输信号的方法和装置
JP2019035724A (ja) 光ファイバ歪み測定装置及び光ファイバ歪み測定方法
JP7351365B1 (ja) 光ファイバセンサ及びブリルアン周波数シフト測定方法

Legal Events

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

Ref document number: 19922017

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: 19922017

Country of ref document: EP

Kind code of ref document: A1