CN115235367A - High-precision dual-frequency optical frequency domain reflectometer with large strain measurement range - Google Patents
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/161—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by interferometric means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
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- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
- G01D5/35387—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques using wavelength division multiplexing
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Abstract
The invention discloses a high-precision double-frequency optical frequency domain reflectometer with a large strain measurement range, which comprises: the light modulation module is used for combining the continuous light into beams and modulating the dual-frequency continuous light into sweep-frequency continuous light; the optical interference module is used for interfering the backward scattering light emitted by the optical fiber to be detected with the sweep frequency continuous light and adjusting the polarization state of the backward scattering light to obtain interference light; the photoelectric conversion module is used for converting the interference light into an electric signal; and the acquisition and processing module is connected with the photoelectric conversion module and is used for acquiring data and analyzing and processing the data. The double-frequency optical frequency domain reflectometer utilizes the phase difference of two frequency light waves to carry out strain measurement, solves the problem that the maximum dynamic strain measurable by a single-frequency optical system is limited by the optical frequency under the condition that the frequency sweeping repetition frequency and the applied strain vibration frequency are not changed, and keeps high-precision measurement.
Description
Technical Field
This patent belongs to the optical fiber sensing field, specifically is a high accuracy dual-frenquency optical frequency domain reflectometer of big measurement of strain scope.
Background
The distributed optical fiber sensing technology has the advantages of electromagnetic interference resistance, high sensitivity, easiness in implementation and the like, and is widely applied to the fields of perimeter security, structural health monitoring, seismic wave detection and the like. When the optical fiber to be measured is disturbed by the external environment (such as dynamic strain), the length, the core diameter and the refractive index characteristics of the optical fiber will be changed, so that the amplitude and the phase of the Rayleigh scattering light in the optical fiber are changed; the detection of the disturbance signals is realized by analyzing the Rayleigh scattering signals before and after the disturbance event. In early sensing systems, one could locate the disturbance event based only on the relative change in rayleigh scattering signal intensity, and could not achieve quantitative measurements. Further research shows that the variation of the phase of the rayleigh scattering signal is linear with the strain applied to the optical fiber, so that the magnitude of the dynamic strain can be quantitatively measured by demodulating the phase variation of the probe light.
Among many detection methods, the phase-sensitive optical frequency domain reflectometer has attracted much attention because of its advantages such as high resolution and high sensitivity. The optical frequency domain reflection technology utilizes frequency modulation continuous waves as detection light, the spatial resolution of the optical frequency domain reflection technology depends on the sweep frequency range, and the problem that the spatial resolution and the detection distance are mutually restricted in a pulse detection mode is solved. The phase-sensitive optical frequency domain reflectometer demodulates the phase spectrum of the Rayleigh scattering signal, and performs phase difference before and after a strain event to acquire the phase change, so as to demodulate the dynamic strain applied to the optical fiber.
In the process of measuring dynamic strain by using a phase-sensitive optical frequency domain reflectometer, a phase measurement value needs to be unfolded by using a unwrapping algorithm so as to make the phase continuous. However, a prerequisite for correct demodulation using the unwrapping algorithm is that the absolute value of the phase change of adjacent measurement points cannot exceed pi (pi threshold condition), which limits the maximum range of measurable dynamic strain. Assuming that the applied dynamic strain is a single-frequency sinusoidal signal, the measurable dynamic strain of the system can be obtained according to the pi threshold condition:
in the formula (f) p Frequency sweep repetition frequency, f, for optical frequency domain reflectometers ε Is the frequency of vibration at which strain is applied. In the prior art, a phase-sensitive optical frequency domain reflection system detects single-frequency light with the optical wavelength near 1550nm (optical frequency-193.5 THz), and as can be seen from the above formula, the maximum measurable dynamic strain is limited by the optical frequency v under the condition that the frequency sweeping repetition frequency and the applied strain vibration frequency are not changed.
Disclosure of Invention
In order to solve the problem that the maximum measurable dynamic strain is limited by the optical frequency v under the condition that the frequency sweeping repetition frequency and the applied strain vibration frequency are not changed, the invention provides a high-precision double-frequency optical frequency domain reflectometer which utilizes the phase difference of two frequency optical waves to measure the strain. The method is equivalent to forming a low-frequency carrier in a measuring system, and the measuring range of the strain is enlarged; the measurement system adopts Fourier phase spectrum to demodulate, and guides single-frequency light phase unwrapping by means of phase difference between double-frequency light, thereby realizing high-precision measurement in a large dynamic strain range.
In order to achieve the purpose, the invention provides the following scheme: a high-precision dual-frequency optical frequency domain reflectometer with a large strain measurement range, comprising:
the light modulation module is used for combining the continuous light emitted by the laser into dual-frequency continuous light and modulating the dual-frequency continuous light into sweep-frequency continuous light;
the optical interference module is used for interfering the backward scattering light emitted by the optical fiber to be detected with the sweep frequency continuous light and adjusting the polarization state of the backward scattering light to obtain interference light;
the photoelectric conversion module is used for converting the interference light into an electric signal;
and the acquisition and processing module is connected with the photoelectric conversion module and is used for analyzing and processing the electric signals.
Preferably, the light modulation module and the light interference module are connected through a first optical coupler;
the optical interference module is connected with the photoelectric conversion module through a second optical coupler;
the first optical coupler and the second optical coupler are used for splitting light.
Preferably, the light modulation module comprises a beam combination unit and a conversion unit;
the beam combination unit is used for combining continuous light into dual-frequency continuous light;
the conversion unit is used for modulating the dual-frequency continuous light into sweep frequency continuous light.
Preferably, the beam combining unit comprises a narrow linewidth laser and a first wavelength division multiplexer;
the narrow linewidth laser comprises a first narrow linewidth laser and a second narrow linewidth laser;
the first narrow linewidth laser is used for emitting continuous light of a first optical frequency;
the second narrow linewidth laser is used for emitting continuous light of a second light frequency;
the first wavelength division multiplexer is configured to combine the continuous light of the first light frequency and the continuous light of the second light frequency.
Preferably, the conversion unit comprises an arbitrary waveform generator, a radio frequency amplifier and a modulator;
the arbitrary waveform generator is used for sending a frequency sweeping signal;
the radio frequency amplifier is connected with the arbitrary waveform generator and is used for amplifying the sweep frequency signal;
and the modulator is connected with the radio frequency amplifier and is used for modulating the dual-frequency continuous light into sweep frequency continuous light.
Preferably, the optical interference module comprises a first optical coupler, an optical amplifier, an optical fiber to be tested, an optical circulator, a polarization controller and a second optical coupler;
the first optical coupler is used for splitting light waves, wherein one path is a detection path, and the other path is a reference path;
the optical amplifier is connected with the first optical coupler and used for increasing the fiber-incoming optical power;
the optical fiber to be detected is used for generating backward Rayleigh scattering light;
the optical circulator is respectively connected with the optical amplifier, the optical fiber to be detected and the polarization controller, and is used for injecting light waves into the optical fiber to be detected, receiving backward Rayleigh scattering light generated by the optical fiber to be detected and emitting the backward Rayleigh scattering light to the polarization controller;
the polarization controller is used for adjusting the polarization state.
And the second optical coupler is used for interfering the optical combined beams of the detection path and the reference path.
Preferably, the photoelectric conversion module includes a second wavelength division multiplexer, a third wavelength division multiplexer, a first photodetector, and a second photodetector;
the second wavelength division multiplexer and the third wavelength division multiplexer are connected with the second optical coupler and are used for wavelength division demultiplexing;
the first photoelectric detector is respectively connected with the second wavelength division multiplexer and the third wavelength division multiplexer and used for receiving beat frequency signals of a first optical frequency;
and the second photoelectric detector is respectively connected with the second wavelength division multiplexer and the third wavelength division multiplexer and is used for receiving beat frequency signals of a second optical frequency.
The invention discloses the following technical effects:
1. the phase-sensitive optical frequency domain reflectometer can adjust the sweep frequency range, obtain high spatial resolution and solve the problem that the spatial resolution and the detection distance cannot be considered in a pulse detection mode; and the frequency domain Fourier phase is adopted for demodulation, so that the method has the advantage of high sensitivity.
2. By adopting the double-frequency measurement system provided by the invention, the phase difference between two frequencies is utilized for demodulation, and compared with the traditional single-frequency optical detection mode, the measurement range of dynamic strain is greatly improved. By using continuous light with the first frequency and the second frequency for detection, the measurable dynamic strain of the dual-frequency measurement system is increased to the value obtained by dividing the first frequency by the frequency difference (or dividing the second frequency by the frequency difference) in the single-frequency measurement system.
3. In order to improve the measurement accuracy, the phase difference between the double-frequency light is used for guiding the single-frequency light phase to be unwound during phase demodulation, so that the measurement accuracy of the double-frequency light system is improved to the level of the single-frequency light system. The high-precision double-frequency optical frequency domain reflectometer provided by the invention provides an effective detection means for application scenes with large strain and high vibration frequency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a system architecture of a dual-frequency optical frequency domain reflectometer according to an embodiment of the present invention;
in the figure: the device comprises a first narrow linewidth laser 1, a second narrow linewidth laser 2, a first wavelength division multiplexer 3, a modulator 4, an arbitrary waveform generator 5, a radio frequency amplifier 6, a first optical coupler 7, an optical amplifier 8, an optical circulator 9, an optical fiber to be tested 10, a polarization controller 11, a second optical coupler 12, a second wavelength division multiplexer 13, a third wavelength division multiplexer 14, a first photodetector 15, a second photodetector 16 and a data acquisition and processor 17.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1, the present invention provides a high-precision dual-frequency optical frequency domain reflectometer with a large strain measurement range, and the system structure thereof is as follows: the first narrow linewidth laser 1 and the second narrow linewidth laser 2 respectively emit frequenciesV is 1 V and v 2 The continuous light is combined by a first wavelength division multiplexer 3, and the first wavelength division multiplexer 3 is connected with an optical input port of a modulator 4; the arbitrary waveform generator 5 is connected with a radio frequency amplifier 6, the output end of the radio frequency amplifier 6 is connected with the radio frequency input end of a modulator 4, the combined beam light is modulated into sweep frequency continuous light, the light output port of the modulator 4 is connected with a first optical coupler 7, the first optical coupler 7 is divided into two paths, one path is a detection path and is sequentially connected with an optical amplifier 8 and a port a of an optical circulator 9, a port b of the optical circulator 9 is connected with an optical fiber 10 to be detected, and a port c is connected with a polarization controller 11; the other output of the first optical coupler 7 is used as a reference path. The detection path and the reference path are connected with a second optical coupler 12, two output ports of the second optical coupler 12 are respectively connected with a second wavelength division multiplexer 13 and a third wavelength division multiplexer 14, and the two wavelength division multiplexers enable the frequency to be v 1 V and v 2 The continuous light is divided, and then the first photoelectric detector 15 and the second photoelectric detector 16 are respectively connected, and after the optical signal is converted into an electric signal, the electric signal is accessed into the data acquisition and processor 17.
Further optimizing the scheme, the optical frequency v of the first narrow linewidth laser 1 And optical frequency v of a second narrow linewidth laser 2 Can differ by several hundred GHz to several THz.
Further optimization, the splitting ratio of the first optical coupler 7 is 90; the splitting ratio of the second optical coupler 12 is 50.
Further, the scheme is optimized, and the optical fiber 10 to be measured can be a common single mode optical fiber, a polarization maintaining optical fiber, an FBG optical fiber, a rayleigh scattering enhanced optical fiber and the like.
Further optimizing the scheme, the demodulation method of the signal is as follows:
firstly, time domain beat frequency signals acquired by each sweep frequency period are subjected to Fourier transform to a frequency domain for analysis, wherein the beat frequency size reflects the position information of an optical fiber, and the Fourier phase under a certain frequency reflects the phase information at a corresponding position;
secondly, extracting Fourier phase information of the frequency domain signals in each sweep frequency period under the two single frequencies, and solving the two single frequencies at each moment through the difference on a distance axis and a slowly-varying time axisThe winding values of the phase changes caused by the strain are respectively
And
thirdly, calculating the phase difference of the two single-frequency lights
Comprises the following steps:
wherein n is the refractive index of the optical fiber, κ is the strain coefficient of the optical fiber, L is the length of the strain region, ε is the magnitude of the strain, and c is the speed of light in vacuum. Wherein Δ ν = ν 1 -ν 2 The frequency difference between the two optical waves. From the above formula, compared with single-frequency light, the phase change caused by the same strain magnitude in the dual-frequency measurement system
Reduced and thus a greater range of dynamic strains can be measured. Using frequency v 1 V and v 2 When continuous light is detected, the measurable dynamic strain of the double-frequency measurement system is increased to a single frequency v 1 V under measurement system 1 V times of/delta v (or single frequency v) 2 V under measuring system 2 V times/Δ);
fourthly, in order to improve the measurement precision under the dual-frequency system, the phase difference between the dual-frequency light is utilized
Single frequency optical phase unwrapping is directed. At a frequency v 1 Taking single-frequency light as an example, the phase change after single-frequency photolytic winding caused by strain
To wind phase
Plus an integer multiple of 2 pi, i.e.
Unwinding into an unwinding integer k 1 A value of (d); let the scale factor M 1 ＝ν 1 V, [ delta ] v, according to formula
Solving an integer k 1 Is further demodulated to obtain
The accuracy under single-frequency light measurement is maintained;
and fifthly, obtaining the strain magnitude epsilon according to the linear relation between the phase change and the strain, and corresponding the strain magnitude epsilon obtained by demodulating each moment to a slow-varying time axis to obtain a strain curve which is caused by vibration and changes along with time.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (7)
1. A high-precision dual-frequency optical frequency domain reflectometer with a large strain measurement range is characterized by comprising:
the light modulation module is used for combining continuous light emitted by the laser into dual-frequency continuous light and modulating the dual-frequency continuous light into sweep frequency continuous light;
the optical interference module is used for interfering the backward scattering light emitted by the optical fiber to be detected with the sweep frequency continuous light and adjusting the polarization state of the backward scattering light to obtain interference light;
the photoelectric conversion module is used for converting the interference light into an electric signal;
and the acquisition and processing module is connected with the photoelectric conversion module and is used for analyzing and processing the electric signals.
2. The large strain measurement range high precision dual frequency optical frequency domain reflectometer as in claim 1,
the light modulation module is connected with the light interference module through a first optical coupler;
the optical interference module is connected with the photoelectric conversion module through a second optical coupler.
3. The large-strain-measurement-range high-precision dual-frequency optical frequency domain reflectometer as in claim 1,
the light modulation module comprises a beam combination unit and a conversion unit;
the beam combination unit is used for combining the continuous light into dual-frequency continuous light;
the conversion unit is used for modulating the dual-frequency continuous light into sweep frequency continuous light.
4. The large strain measurement range high precision dual frequency optical frequency domain reflectometer as in claim 3,
the beam combining unit comprises a narrow linewidth laser and a first wavelength division multiplexer;
the narrow linewidth laser comprises a first narrow linewidth laser and a second narrow linewidth laser;
the first narrow linewidth laser is used for emitting continuous light of a first optical frequency;
the second narrow linewidth laser is used for emitting continuous light of a second optical frequency;
the first wavelength division multiplexer is used for combining the continuous light of the first light frequency and the continuous light of the second light frequency.
5. The large strain measurement range high precision dual frequency optical frequency domain reflectometer as in claim 3,
the conversion unit comprises an arbitrary waveform generator, a radio frequency amplifier and a modulator;
the arbitrary waveform generator is used for sending out a frequency sweeping signal;
the radio frequency amplifier is connected with the arbitrary waveform generator and is used for amplifying the sweep frequency signal;
and the modulator is connected with the radio frequency amplifier and is used for modulating the dual-frequency continuous light into sweep frequency continuous light.
6. The large-strain-measurement-range high-precision dual-frequency optical frequency domain reflectometer as in claim 1,
the optical interference module comprises a first optical coupler, an optical amplifier, an optical fiber to be tested, an optical circulator, a polarization controller and a second optical coupler;
the first optical coupler is used for splitting light waves, wherein one path is a detection path, and the other path is a reference path;
the optical amplifier is connected with the first optical coupler and used for increasing the fiber-incoming optical power;
the optical fiber to be detected is used for generating backward Rayleigh scattering light;
the optical circulator is respectively connected with the optical amplifier, the optical fiber to be detected and the polarization controller, and is used for injecting light waves into the optical fiber to be detected, receiving backward Rayleigh scattered light generated by the optical fiber to be detected and then emitting the backward Rayleigh scattered light to the polarization controller;
the polarization controller is used for adjusting the polarization state;
and the second optical coupler is used for interfering the optical combined beams of the detection path and the reference path.
7. The large-strain-measurement-range high-precision dual-frequency optical frequency domain reflectometer as in claim 1,
the photoelectric conversion module comprises a second wavelength division multiplexer, a third wavelength division multiplexer, a first photoelectric detector and a second photoelectric detector;
the second wavelength division multiplexer and the third wavelength division multiplexer are connected with the second optical coupler and are used for wavelength division demultiplexing;
the first photoelectric detector is respectively connected with the second wavelength division multiplexer and the third wavelength division multiplexer and used for receiving beat frequency signals of a first optical frequency;
and the second photoelectric detector is respectively connected with the second wavelength division multiplexer and the third wavelength division multiplexer and is used for receiving beat frequency signals of a second optical frequency.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1145927A (en) * | 1981-10-23 | 1983-05-10 | Marc Bage | Method and apparatus for optical fiber fault location |
| JPH09218130A (en) * | 1996-02-09 | 1997-08-19 | Nippon Telegr & Teleph Corp <Ntt> | Method and circuit for detecting frequency sweep error, optical frequency sweep light source, and optical frequency area reflection measuring circuit |
| US20070171402A1 (en) * | 2004-05-01 | 2007-07-26 | Sensornet Limited | Direct measurement of brillouin frequency in destributed optical sensing systems |
| CN103984184A (en) * | 2014-05-19 | 2014-08-13 | 上海交通大学 | Light pulse compression reflecting device |
| CN205453695U (en) * | 2016-01-05 | 2016-08-10 | 上海交通大学 | Optical frequency territory reflect meter based on frequency synthesis |
| CN107990997A (en) * | 2017-11-20 | 2018-05-04 | 大连理工大学 | A kind of double light source self-correction formula fiber optic Distributed Temperature Fast measurement systems and method |
| CN110375779A (en) * | 2019-07-29 | 2019-10-25 | 武汉隽龙科技股份有限公司 | The device and method for improving OFDR frequency domain sample rate |
| CN110914645A (en) * | 2017-07-26 | 2020-03-24 | 特拉15私人有限公司 | Distributed optical sensing system and method |
| CN113654679A (en) * | 2021-07-30 | 2021-11-16 | 太原理工大学 | Distributed optical fiber temperature and strain simultaneous sensing system |
| US20210364385A1 (en) * | 2020-05-25 | 2021-11-25 | Aragon Photonics Labs S.L.U. | Method and system for interrogating optical fibers |
| US20220149934A1 (en) * | 2019-02-12 | 2022-05-12 | Nippon Telegraph And Telephone Corporation | Device for measuring optical frequency reflection and measurement method thereof |
-
2022
- 2022-07-26 CN CN202210886933.XA patent/CN115235367B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1145927A (en) * | 1981-10-23 | 1983-05-10 | Marc Bage | Method and apparatus for optical fiber fault location |
| JPH09218130A (en) * | 1996-02-09 | 1997-08-19 | Nippon Telegr & Teleph Corp <Ntt> | Method and circuit for detecting frequency sweep error, optical frequency sweep light source, and optical frequency area reflection measuring circuit |
| US20070171402A1 (en) * | 2004-05-01 | 2007-07-26 | Sensornet Limited | Direct measurement of brillouin frequency in destributed optical sensing systems |
| CN103984184A (en) * | 2014-05-19 | 2014-08-13 | 上海交通大学 | Light pulse compression reflecting device |
| CN205453695U (en) * | 2016-01-05 | 2016-08-10 | 上海交通大学 | Optical frequency territory reflect meter based on frequency synthesis |
| CN110914645A (en) * | 2017-07-26 | 2020-03-24 | 特拉15私人有限公司 | Distributed optical sensing system and method |
| CN107990997A (en) * | 2017-11-20 | 2018-05-04 | 大连理工大学 | A kind of double light source self-correction formula fiber optic Distributed Temperature Fast measurement systems and method |
| US20220149934A1 (en) * | 2019-02-12 | 2022-05-12 | Nippon Telegraph And Telephone Corporation | Device for measuring optical frequency reflection and measurement method thereof |
| CN110375779A (en) * | 2019-07-29 | 2019-10-25 | 武汉隽龙科技股份有限公司 | The device and method for improving OFDR frequency domain sample rate |
| US20210364385A1 (en) * | 2020-05-25 | 2021-11-25 | Aragon Photonics Labs S.L.U. | Method and system for interrogating optical fibers |
| CN113654679A (en) * | 2021-07-30 | 2021-11-16 | 太原理工大学 | Distributed optical fiber temperature and strain simultaneous sensing system |
Non-Patent Citations (3)
| Title |
|---|
| A.H.HARTOG: "The use of multi-frequency acquisition to aignificantly improve the quality of fibre-optic-distributed vibration sensing" * |
| WEIWEN ZOU: "Range Elongation of Distributed Discrimination of Strain and Temperature in Brillouin Optical Correlation-Domain Analysis Based on Dual Frequency Modulations" * |
| 董毅: "延迟自外差锁相控制的激光线性扫频技术及其应用" * |
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