CN108286992B - Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation - Google Patents
Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation Download PDFInfo
- Publication number
- CN108286992B CN108286992B CN201810012818.3A CN201810012818A CN108286992B CN 108286992 B CN108286992 B CN 108286992B CN 201810012818 A CN201810012818 A CN 201810012818A CN 108286992 B CN108286992 B CN 108286992B
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- polarization
- polarization direction
- signal
- light
- 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.)
- Active
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 223
- 238000000034 method Methods 0.000 title claims abstract description 13
- 230000010287 polarization Effects 0.000 claims abstract description 185
- 230000003287 optical effect Effects 0.000 claims abstract description 46
- 238000001514 detection method Methods 0.000 claims abstract description 34
- 230000009471 action Effects 0.000 claims abstract description 4
- 238000010586 diagram Methods 0.000 claims description 9
- 238000010408 sweeping Methods 0.000 claims description 8
- 238000001228 spectrum Methods 0.000 claims description 4
- 238000000605 extraction Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 230000003595 spectral effect Effects 0.000 claims description 2
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 239000000835 fiber Substances 0.000 description 10
- 230000001427 coherent effect Effects 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 230000005611 electricity Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 230000007123 defense Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
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
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
- G01D5/35329—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using interferometer with two arms in transmission, e.g. Mach-Zender interferometer
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Optical Communication System (AREA)
Abstract
The invention discloses a distributed optical fiber acoustic sensing device and a method based on digital double-chirp pulse modulation, which are used for long-distance distributed acoustic detection, and are characterized in that a double-polarization four-parallel Mach-Zehnder electro-optic modulator is used for carrying out chirp pulse modulation in X and Y polarization directions respectively, chirp pulse light signals in the X polarization direction are used as detection light pulses, the detection light pulses are injected into a sensing optical fiber after being amplified by an erbium-doped optical fiber amplifier, chirp pulse light signals in a continuous equal sweep frequency range in the Y polarization direction are used as reference light, the detection light pulses are mixed with backscattering chirp pulse light signals carrying optical phase and frequency information at each position of the sensing optical fiber through an optical coupler, the interfered optical signals are separated to two polarization directions by two optical fiber polarization beam splitters for detection and reception, and the phase, the amplitude and the frequency of the acoustic action position of the sensing. The invention combines optical fiber sensing and transmission into a whole, and solves the difficult problem that the long distance and high resolution of optical fiber distributed acoustic signal sensing are difficult to reconcile.
Description
Technical Field
The invention belongs to the field of distributed optical fiber sound sensing detection, and particularly relates to a distributed sound sensing device and method based on digital double-chirp pulse modulation, which can be used for detection in the fields of oceans, aviation, petroleum, rock and soil and the like.
Background
The sound wave detection technology has wide application and requirements in the fields of petroleum/mineral exploration based on seismic wave detection, anti-submarine battles based on underwater sound detection, air sound-based flyer monitoring, vibration-based perimeter safety monitoring, battlefield reconnaissance and the like. The traditional sound wave detection technology mainly adopts a microphone array constructed based on an electric microphone to collect and receive sound field signals, and is mainly characterized by a discrete structure and strict synchronous collection requirements, so that the microphone array is greatly limited in scale and is influenced by severe working environments such as electromagnetic interference, high temperature and high humidity and the like. In recent years, a distributed optical fiber sensing technology is concerned, but in a coherent domain reflection technology of a synthetic coherent function light, the measurement range is limited and is generally thousands of meters, wherein the influence of the modulation rate of a light source frequency is applied to the technology; for the traditional phase optical time domain reflection technology, the optical pulse width and the pulse energy need to be considered in a compromise mode, the synchronous improvement of the spatial resolution, the signal-to-noise ratio and the dynamic range is limited, and the real acoustic wave distribution sensing requirement is difficult to meet. In order to overcome the problem, a digital double-chirp pulse modulation distributed optical fiber acoustic sensing device and a method are provided, and the technology provides an efficient and low-cost technical scheme for the fields of oil and gas exploration, production monitoring and national defense safety and has good application prospects.
Disclosure of Invention
The invention aims to provide a distributed optical fiber acoustic sensing device and a method based on digital double-chirp pulse modulation, which combine the sensing and transmission functions of an optical fiber into a whole, have the advantages of no electromagnetic interference, no electricity and no source, small volume and the like, and realize distributed measurement to greatly expand the scale of sensing monitoring points.
A distributed optical fiber acoustic sensing device based on digital double-chirp pulse modulation is used for long-distance distributed acoustic detection and comprises a light source 1, a polarization-maintaining optical fiber isolator 2, a double-polarization four-parallel Mach-Zehnder electro-optic modulator 3, an arbitrary waveform generator 4 for driving the X polarization direction, an arbitrary waveform generator 5 for driving the Y polarization direction, an electro-optic modulator bias voltage control board 6, a 1X 2 polarization-maintaining optical fiber coupler 7, a first optical fiber polarization beam splitter 8, an erbium-doped optical fiber amplifier 9, an optical fiber filter 10, an optical fiber circulator 11, a sensing optical fiber 12, a 2X 2 optical fiber coupler 13, a second optical fiber polarization beam splitter 14, a third optical fiber polarization beam splitter 15, an X polarization direction balancing photoelectric detector 16, a Y polarization direction balancing photoelectric detector 17, a data acquisition card 18 and a processing unit 19; wherein:
the continuous laser output end of the light source 1 is connected with the input end of the polarization maintaining optical fiber isolator 2; the output end of the polarization-maintaining optical fiber isolator 2 is connected with the input end of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator 3, and is connected with the 1 x 2 polarization-maintaining optical fiber coupler 7 through the output end of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator 3; one output end of the 1 x 2 polarization-maintaining optical fiber coupler 7 is connected with the input end of a photoelectric detector on the bias control board 6 of the electro-optical modulator, and the other output end is connected with the input end of a first optical fiber polarization beam splitter 8; the output end of the first optical fiber polarization beam splitter 8 is sequentially connected with an erbium-doped optical fiber amplifier 9, an optical fiber filter 10 and an optical fiber circulator 11, one output end of the optical fiber circulator 11 is injected into a sensing optical fiber 12, and the other output end of the optical fiber circulator is connected with a 2 x 2 optical fiber coupler 13; one output end of the 2X 2 optical fiber coupler 13 is connected to a second optical fiber polarization beam splitter 14, an output end of the second optical fiber polarization beam splitter 14 is connected to an input end of an X polarization direction balancing photodetector 16, the other output end of the 2X 2 optical fiber coupler 13 is connected to an input end of a third optical fiber polarization beam splitter 15, and an output end of the third optical fiber polarization beam splitter 15 is connected to a Y polarization direction balancing photodetector 17; the output end of the X polarization direction balancing photodetector 16 and the output end of the Y polarization direction balancing photodetector 17 are respectively used as the input ends electrically connected to the data acquisition card 18, and the data acquisition card 18 transmits data to the processing unit 19 for processing; chirp pulse digital signals which are generated by the arbitrary waveform generator 4 for driving the X polarization direction and the arbitrary waveform generator 5 for driving the Y polarization direction and have the same linear chirp range and the same frequency sweep rate are respectively loaded to the X polarization direction and the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator 3; the chirp pulse light signal in the X polarization direction is used as a detection light pulse, and the chirp pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as a reference light;
the polarization maintaining optical fiber isolator 2 is used for isolating laser reflected back from the optical fiber and avoiding interference and damage caused by the laser entering the optical fiber;
the dual-polarization four-parallel Mach-Zehnder electro-optic modulator 3 is used for carrying out I/Q modulation on laser in the X polarization direction and the Y polarization direction respectively;
the X polarization direction driving arbitrary waveform generator 4 is used for generating chirped pulse waveforms, the range of frequency sweeping signals is 0.1-20 GHz, and the output signals of the I path and the Q path respectively drive the X polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the Y polarization direction driving arbitrary waveform generator 5 is used for generating chirped pulse waveforms, the range of frequency sweeping signals is 0.1-20 GHz, and the output signals of the I path and the Q path respectively drive the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the bias control board 6 of the electro-optical modulator automatically adjusts the polarization control point according to the feedback light intensity, so that the polarization control point is stabilized in a set working mode;
one output optical fiber of the 1 × 2 polarization maintaining optical fiber coupler 7 is connected with a photoelectric detector on a bias control board of the electro-optical modulator, and is used for extracting and feeding back the modulated chirped pulse optical signal;
the first optical fiber polarization beam splitter 8 is configured to split an optical signal into light with two polarization directions, namely X and Y;
the erbium-doped optical fiber amplifier 9 is used for amplifying signal light generated through modulation, has gain of 10-30 dB, and meets the requirement of long-distance detection.
The optical fiber filter 10 is used for performing band-pass filtering on the optical signal amplified by the erbium-doped optical fiber amplifier to eliminate ASE noise.
The optical fiber circulator 11 inputs the detected scattered chirped pulse light into the sensing optical fiber and inputs the backscattered chirped pulse light into the demodulation optical path;
the sensing optical fiber 12 is used for transmitting and detecting a scattered chirped pulse optical signal and a back scattered chirped pulse optical signal and sensing a to-be-measured value;
2, an optical fiber coupler 13 for combining the reference chirped pulse light and the backscattered chirped pulse light in the sensing optical fiber to generate interference;
the second optical fiber polarization beam splitter 14 is configured to split one path of interference optical signal output by the 2X 2 optical fiber coupler into light in two polarization directions of X and Y;
the third optical fiber polarization beam splitter 15 is configured to split another path of interference optical signal output by the 2X 2 optical fiber coupler into light in two polarization directions of X and Y;
the X polarization direction balancing photodetector 16 is configured to convert an X component part of an optical interference signal generated by the reference chirped pulse light and the backscattered chirped pulse light in the sensing fiber into an electrical signal;
the Y polarization direction balancing photodetector 17 is configured to convert a Y component part of an optical interference signal generated by the reference chirped pulse light and the backscattered chirped pulse light in the sensing fiber into an electrical signal;
the data acquisition card 18 is used for acquiring and receiving the voltage analog signal converted by the balanced photoelectric detector;
the processing unit 19 is used for controlling signal generation and signal reception, and receiving and demodulating signals of the photoelectric detector to obtain phase, amplitude and frequency information of the position of the sensing optical fiber acted by the sound wave, and the implementation form includes a computer and an embedded computing system.
The invention discloses a distributed optical fiber acoustic sensing method based on digital double-chirp pulse modulation, which is used for long-distance distributed acoustic detection and comprises the following specific processes:
first, the light frequency emitted by the light source is omega0The continuous laser light enters a dual-polarization four-parallel Mach-Zehnder electro-optic modulator after passing through a polarization-maintaining optical fiber isolator; two arbitrary waveform generators, namely an arbitrary waveform generator for driving in the X polarization direction and the Y polarization direction, respectively generate chirp pulse digital signals with the same linear chirp range and the same frequency sweeping rate, and respectively load the chirp pulse digital signals into the X polarization direction and the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator; the chirp pulse light signal in the X polarization direction is used as a detection light pulse, and the chirp pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as a reference light;
secondly, dividing the chirped pulse light signal modulated by the dual-polarization four-parallel Mach-Zehnder electro-optic modulator into two parts through a 1-to-2 polarization-maintaining optical fiber coupler, wherein one path of output optical fiber is connected with a photoelectric detector on a bias control board of the electro-optic modulator and is used for extracting and feeding back the modulated chirped pulse light signal so as to keep the chirped pulse light signal in a stable working state for a long time; the other path of the chirped pulse light signal is split into an X polarization direction and a Y polarization direction through a first optical fiber polarization beam splitter, the chirped pulse light signal in the X polarization direction as a detection light pulse signal is amplified by an erbium-doped optical fiber amplifier, is injected into a sensing optical fiber after passing through an optical fiber filter and an optical fiber circulator, and is subjected to backward Rayleigh scattering in passing optical fibers, and the backward scattered chirped pulse light returns to a demodulation optical path along the optical fibers; the back scattering chirp pulse light containing the linear frequency sweep light used for demodulating phase information phi (t) and for demodulating optical frequency information I (omega) is subjected to mixed interference with the chirp pulse light signal in the continuous equal frequency sweep range of the Y polarization direction;
thirdly, outputting the backscattered chirped pulse light signal and the local reference chirped pulse light signal after interference in a 2X 2 optical fiber coupler, wherein one path of interference light signal is divided into light in X and Y polarization directions by a second optical fiber polarization beam splitter, and the other path of interference light signal is divided into light in X and Y polarization directions by a third optical fiber polarization beam splitter; the X component part and the Y component part of the interference signal are respectively converted into electric signals through an X polarization direction balancing photoelectric detector and a Y polarization direction balancing photoelectric detector, fast Fourier transform is respectively carried out on the two paths of signals to obtain FFT (X) signals and FFT (Y) signals, and each position in the sensing optical fiber is sequentially selected by using a moving window; then the distance domain information FFT (X) of the ith section of the sensing optical fiber selected by using the moving windowi) And FFT (Y)i) Performing an inverse Fourier transform to the optical frequency domain to obtain a corresponding XiAnd YiAnd summing the two to obtain the sum at t1Rayleigh scattering spectral information S (t) at time1)＝Xi+YiRemoving the direct current term; at the next time t2Calculating and obtaining Rayleigh scattering spectrum information S (t) at the same position of the sensing optical fiber according to the first two steps2)＝Xi+YiFor S (t)1) And S (t)2) And performing cross-correlation operation to obtain a cross-correlation coefficient and the noise level of the correlation diagram, and obtaining whether the sensing optical fiber has the acoustic wave action and the acoustic wave intensity at the position according to the cross-correlation peak coefficient and the noise level of the correlation diagram.
Step four, calculating the spatial resolution of the system
Wherein tau is the chirp pulse width, and gamma is the chirp pulse scanning speed; the detection of the vibration frequency, amplitude and phase information of the sound source is realized through a phase extraction algorithm; the spatial resolution is determined by the frequency sweep range of the chirped pulse and is inversely related to the frequency sweep range.
Compared with the prior art, the invention has the following effects:
1. the invention utilizes the function of integrating optical fiber sensing and transmission, has the advantages of no electromagnetic interference, no electricity source, small volume, high temperature and high humidity resistance and other severe working environments, and greatly expands the scale of the sensing monitoring point by realizing distributed measurement.
2. The detection light signal and the local reference light signal are respectively modulated into independent linear frequency chirp pulse light, and the position of a reflection point on an optical fiber is determined according to the time delay of a driving signal for generating two paths of pulses; the time delay is independent of the waveform of the modulation signal, so that the position of coherent detection is independent of the modulation signal.
3. The invention does not need high-speed data acquisition equipment and a complex data processing process, and the whole data processing is relatively simple. In the technical scheme, an optical delay line is not needed, the measurement distance is not influenced by the distance between coherent peaks in the traditional coherent domain reflection system, and the difficult problem that the long distance and high resolution of optical fiber distributed acoustic signal sensing are difficult to reconcile is solved.
Drawings
FIG. 1 is a schematic diagram of a distributed fiber optic acoustic sensing device based on digital double chirp pulse modulation according to the present invention;
fig. 2 is a schematic diagram of the modulation results of the chirped pulse signal detection and the local reference chirped pulse signal in the present invention;
fig. 3 is a schematic diagram of the coherence of the backscattered chirped pulse light signal and the local reference chirped pulse light signal at different reflection points on the optical fiber according to the present invention.
Reference numerals: 1. the optical fiber polarization splitter comprises a light source, a polarization maintaining optical fiber isolator, a double-polarization four-parallel Mach-Zehnder electro-optic modulator, an X polarization direction driving arbitrary waveform generator, a Y polarization direction driving arbitrary waveform generator, a 6 electro-optic modulator bias control board, a 7, 1, 2 polarization maintaining optical fiber coupler, a 8, a first optical fiber polarization beam splitter, a 9, an erbium-doped optical fiber amplifier, a 10, an optical fiber filter, a 11, an optical fiber circulator, a 12, a sensing optical fiber, a 13, 2, an optical fiber coupler, a 14, a second optical fiber polarization beam splitter, a 15, a third optical fiber polarization beam splitter, a 16, X polarization direction balancing photoelectric detector, a 17, Y polarization direction balancing photoelectric detector, a 18, a data acquisition card, a 19 and a processing unit.
Detailed Description
Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
Example 1: distributed optical fiber acoustic sensing device based on digital double chirp pulse modulation:
as shown in fig. 1, the distributed optical fiber acoustic sensing device based on digital double-chirp pulse modulation of the present invention includes 19 components, namely, a light source 1, a polarization-maintaining optical fiber isolator 2, a double-polarization four-parallel mach-zehnder electro-optic modulator 3, an arbitrary waveform generator 4 for driving the X polarization direction, an arbitrary waveform generator 5 for driving the Y polarization direction, a bias control board 6 of the electro-optic modulator, a 1X 2 polarization-maintaining optical fiber coupler 7, a first optical fiber polarization beam splitter 8, an erbium-doped optical fiber amplifier 9, an optical fiber filter 10, an optical fiber circulator 11, a sensing optical fiber 12, a 2X 2 optical fiber coupler 13, a second optical fiber polarization beam splitter 14, a third optical fiber polarization beam splitter 15, an X polarization direction balancing photoelectric detector 16, a Y polarization direction balancing photoelectric detector 17, a data acquisition card 18, and a processing unit 19;
the light source 1 emits light with frequency omega0The continuous laser passes through a polarization maintaining fiber isolator 2 and then enters into dual-polarization four-parallel MachA Zehnder electro-optic modulator 3. Chirp pulse digital signals having the same linear chirp range and the same frequency sweep rate are generated by two arbitrary waveform generators (an arbitrary waveform generator 4 for X-polarization direction driving and an arbitrary waveform generator 5 for Y-polarization direction driving), respectively, and are loaded to the two polarization directions X and Y of the dual-polarization four-parallel mach-zehnder electro-optic modulator, respectively. The chirped pulse light signal in the X polarization direction is used as a detection light pulse, and the chirped pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as reference light. The chirped pulse light signal modulated by the dual-polarization four-parallel Mach-Zehnder electro-optic modulator is divided into two parts by the 1-to-2 polarization-maintaining optical fiber coupler 7, wherein one path of output optical fiber is connected with the photoelectric detector on the bias control board 6 of the electro-optic modulator and is used for extracting and feeding back the modulated chirped pulse light signal so as to keep the chirped pulse light signal in a stable working state for a long time. And the other path of the chirped pulse light signal is split into an X polarization direction and a Y polarization direction through a first optical fiber polarization beam splitter 8, the chirped pulse light signal in the X polarization direction as the detection light pulse signal is amplified by an erbium-doped optical fiber amplifier 9, is injected into a sensing optical fiber 12 after passing through an optical fiber filter 10 and an optical fiber circulator 11, and is subjected to backward Rayleigh scattering in the passing optical fiber, and the backward scattered chirped pulse light returns to a demodulation optical path along the optical fiber. The back scattering chirp pulse light containing the linear frequency sweep light for demodulating the phase information phi (t) and for demodulating the optical frequency information I (omega) and the chirp pulse light signal of the continuous equal frequency sweep range in the Y polarization direction are interfered in the 2X 2 optical fiber coupler 13 and then output, one path of interference light signal is divided into light in two polarization directions of X and Y by the second optical fiber polarization beam splitter 14, and the other path of interference light signal is divided into light in two polarization directions of X and Y by the third optical fiber polarization beam splitter 15. The X-component part and the Y-component part of the interference signal are converted into electrical signals by the X-polarization direction and the Y-polarization direction balancing photodetectors 16 and 17, respectively, and then the data are transmitted to the processing unit 19 for processing by the data acquisition card 18.
Wherein:
the light source 1 adopts a narrow linewidth continuous laser with the linewidth of 0.1-100 kHz, and the output power is 1-50 mW. A laser output for providing a long coherence length required by the system;
the polarization maintaining optical fiber isolator 2 is used for isolating laser reflected back from the optical fiber and avoiding interference and damage caused by the laser entering the optical fiber;
the dual-polarization four-parallel Mach-Zehnder electro-optic modulator 3 is used for carrying out I/Q modulation on laser in the X polarization direction and the Y polarization direction respectively, generating chirp pulses in the X polarization direction, wherein the pulse width is 1-100 ns, the pulse period is 1-20 kHz, and the modulation frequency range is 0.1-20 GHz. Generating continuous chirped pulses in the Y polarization direction, wherein the pulse width is 1-100 ns, and the modulation frequency range is 0.1-20 GHz;
the X polarization direction driving arbitrary waveform generator 4 is used for generating a chirped pulse waveform, the range of a frequency sweeping signal is 0.1-20 GHz, and the output signals of the I path and the Q path respectively drive the X polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the Y polarization direction driving arbitrary waveform generator 5 is used for generating a chirped pulse waveform, the range of a frequency sweeping signal is 0.1-20 GHz, and the output signals of the I path and the Q path respectively drive the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the bias control board 6 of the electro-optical modulator can automatically adjust the polarization control point according to the feedback light intensity, so that the polarization control point is stabilized in a set working mode;
1 x 2 polarization maintaining fiber coupler 7, wherein one output fiber is connected with a photoelectric detector on a bias control board of the electric light modulator, and is used for extracting and feeding back the modulated chirp pulse light signal;
a first optical fiber polarization beam splitter 8 for splitting the optical signal into light of two polarization directions of X and Y;
the erbium-doped optical fiber amplifier 9 is used for amplifying signal light generated through modulation, has gain of 10-30 dB, and meets the requirement of long-distance detection.
And the optical fiber filter 10 is used for performing band-pass filtering on the optical signal amplified by the erbium-doped optical fiber amplifier and eliminating ASE noise.
The optical fiber circulator 11 inputs the detected scattered chirped pulse light into the sensing optical fiber and inputs the backscattered chirped pulse light into the demodulation optical path;
the sensing optical fiber 12 is used for transmitting and detecting a scattered chirped pulse optical signal and a back scattered chirped pulse optical signal and sensing a to-be-measured value;
2, an optical fiber coupler 13 for combining the reference chirped pulse light and the backscattered chirped pulse light in the sensing optical fiber to generate interference;
the second optical fiber polarization beam splitter 14 is used for splitting one path of interference optical signal output by the 2X 2 optical fiber coupler into light in two polarization directions of X and Y;
the third optical fiber polarization beam splitter 15 is used for splitting the other path of interference optical signal output by the 2X 2 optical fiber coupler into light in two polarization directions of X and Y;
an X-polarization direction balancing photodetector 16 for converting an X-component part of an optical interference signal generated by the reference chirped pulse light and the backscattered chirped pulse light in the sensing fiber into an electrical signal;
a Y polarization direction balancing photodetector 17 for converting a Y component part of an optical interference signal generated by the reference chirped pulse light and the backscattered chirped pulse light in the sensing fiber into an electrical signal;
the data acquisition card 18 is used for acquiring and receiving the voltage analog signal converted by the balanced photoelectric detector;
and the processing unit 19 is used for controlling signal generation and signal reception, and receiving and demodulating signals of the photoelectric detector, and the implementation forms include a computer and an embedded computing system.
Example 2: a distributed optical fiber acoustic sensing method based on digital double chirp pulse modulation comprises the following steps:
the specific method of the distributed optical fiber acoustic sensing device based on digital double chirp pulse modulation is as follows:
the light source in FIG. 1 emits light at a frequency of ω0The continuous laser light enters a dual-polarization four-parallel Mach-Zehnder electro-optic modulator after passing through a polarization-maintaining fiber isolator. Chirp pulse digital signals having the same linear chirp range and the same frequency sweep rate are respectively generated by two arbitrary waveform generators (an arbitrary waveform generator for driving in the X-polarization direction and an arbitrary waveform generator for driving in the Y-polarization direction) and are respectively applied toThe dual-polarization four-parallel Mach-Zehnder electro-optic modulator has two polarization directions of X and Y. The chirped pulse light signal in the X polarization direction is used as a detection light pulse, and the chirped pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as reference light. The chirped pulse light signal modulated by the dual-polarization four-parallel Mach-Zehnder electro-optic modulator is divided into two parts by a 1-to-2 polarization-maintaining optical fiber coupler, wherein one path of output optical fiber is connected with the photoelectric detector on the bias control board of the electro-optic modulator and is used for extracting and feeding back the modulated chirped pulse light signal so as to keep the chirped pulse light signal in a stable working state for a long time. And the other path of the chirped pulse light signal is split into X polarization and Y polarization directions through a first optical fiber polarization beam splitter, the chirped pulse light signal in the X polarization direction as the detection light pulse signal is amplified by an erbium-doped optical fiber amplifier, is injected into the sensing optical fiber after passing through an optical fiber filter and an optical fiber circulator, and is subjected to backward Rayleigh scattering in the passing optical fiber, and the backward scattered chirped pulse light returns to a demodulation optical path along the optical fiber. The back scattering chirp pulse light containing the linear frequency sweep light used for demodulating phase information phi (t) and for demodulating optical frequency information I (omega) and the chirp pulse light signal of continuous equal frequency sweep range in the Y polarization direction are interfered in a 2X 2 optical fiber coupler and then output, one path of interference light signal is divided into light in X and Y polarization directions by a second optical fiber polarization beam splitter, and the other path of interference light signal is divided into light in X and Y polarization directions by a third optical fiber polarization beam splitter. The X component part and the Y component part of the interference signal are converted into electric signals through the X polarization direction balancing photoelectric detector and the Y polarization direction balancing photoelectric detector respectively, fast Fourier transform is carried out on the two paths of signals respectively to obtain FFT (X) signals and FFT (Y) signals, and each position in the sensing optical fiber is sequentially selected through a moving window. Then, the distance domain information FFT (xi) and FFT (Yi) of the section i of the sensing fiber selected by the moving window are subjected to inverse Fourier transform to the optical frequency domain to obtain XiAnd YiSumming the two to obtain Rayleigh scattering spectrum information S (t1) which is Xi + Yi at the time t1, and removing a direct current term; at the next time t2Calculating and obtaining Rayleigh scattering spectrum information S (t) at the same position of the sensing optical fiber according to the first two steps2) Xi + Yi, for S (t)1) And S (t)2) And performing cross-correlation operation to obtain a cross-correlation coefficient and the noise level of the correlation diagram, and obtaining whether the sensing optical fiber has the acoustic wave action and the acoustic wave intensity at the position according to the cross-correlation peak coefficient and the noise level of the correlation diagram. The spatial resolution of the scheme is determined by the frequency sweep range of the chirped pulse and is in inverse proportion to the frequency sweep range. Spatial resolution of a system
Where τ is the chirp width and γ is the chirp scan speed. And the detection of the vibration frequency, amplitude and phase information of the sound source is realized through a phase extraction algorithm.
Claims (2)
1. The distributed optical fiber acoustic sensing device based on digital double-chirp pulse modulation is used for long-distance distributed acoustic detection and is characterized by comprising a light source (1), a polarization-maintaining optical fiber isolator (2), a double-polarization four-parallel Mach-Zehnder electro-optic modulator (3), an optional waveform generator (4) for driving in the X polarization direction, an optional waveform generator (5) for driving in the Y polarization direction, an electro-optic modulator bias control board (6), a 1X 2 polarization-maintaining optical fiber coupler (7), a first optical fiber polarization beam splitter (8), an erbium-doped optical fiber amplifier (9), an optical fiber filter (10), an optical fiber circulator (11), sensing optical fibers (12), a 2X 2 optical fiber coupler (13), a second optical fiber polarization beam splitter (14), a third optical fiber polarization beam splitter (15), and an X polarization direction balance photoelectric detector (16), A Y polarization direction balancing photoelectric detector (17), a data acquisition card (18) and a processing unit (19); wherein:
the continuous laser output end of the light source (1) is connected with the input end of the polarization maintaining optical fiber isolator (2); the output end of the polarization-maintaining optical fiber isolator (2) is connected with the input end of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator (3), and is connected with the 1 x 2 polarization-maintaining optical fiber coupler (7) through the output end of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator (3); one output end of the 1 x 2 polarization-maintaining optical fiber coupler (7) is connected with the input end of a photoelectric detector on the bias control board (6) of the electro-optical modulator, and the other output end of the 1 x 2 polarization-maintaining optical fiber coupler is connected with the input end of a first optical fiber polarization beam splitter (8); the output end of the first optical fiber polarization beam splitter (8) is sequentially connected with an erbium-doped optical fiber amplifier (9), an optical fiber filter (10) and an optical fiber circulator (11), one output end of the optical fiber circulator (11) is injected into a sensing optical fiber (12), and the other output end of the optical fiber circulator is connected with a 2 x 2 optical fiber coupler (13); one output end of the 2X 2 optical fiber coupler (13) is connected to a second optical fiber polarization beam splitter (14), the output end of the second optical fiber polarization beam splitter (14) is connected to the input end of the X polarization direction balancing photoelectric detector (16), the other output end of the 2X 2 optical fiber coupler (13) is connected to the input end of a third optical fiber polarization beam splitter (15), and the output end of the third optical fiber polarization beam splitter (15) is connected to the Y polarization direction balancing photoelectric detector (17); the output end of the X polarization direction balancing photoelectric detector (16) and the output end of the Y polarization direction balancing photoelectric detector (17) are respectively used as the input ends electrically connected with a data acquisition card (18), and the data acquisition card (18) transmits data to a processing unit (19) for processing; chirp pulse digital signals which are generated by the arbitrary waveform generator (4) for driving the X polarization direction and the arbitrary waveform generator (5) for driving the Y polarization direction and have the same linear chirp range and the same frequency sweep rate are respectively loaded to the X polarization direction and the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator (3); the chirp pulse light signal in the X polarization direction is used as a detection light pulse, and the chirp pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as a reference light;
the polarization maintaining optical fiber isolator (2) is used for isolating laser reflected back from the optical fiber and avoiding interference and damage caused by the laser;
the dual-polarization four-parallel Mach-Zehnder electro-optic modulator (3) is used for carrying out I/Q modulation on laser in the X polarization direction and the Y polarization direction respectively;
the X polarization direction driving arbitrary waveform generator (4) is used for generating chirped pulse waveforms, the range of frequency sweeping signals is 0.1-20 GHz, and the output signals I and Q respectively drive the X polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the Y polarization direction driving arbitrary waveform generator (5) is used for generating chirped pulse waveforms, the range of frequency sweeping signals is 0.1-20 GHz, and the output signals I and Q respectively drive the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator;
the bias control board (6) of the electro-optical modulator automatically adjusts the polarization control point according to the feedback light intensity to enable the polarization control point to be stabilized in a set working mode;
one output optical fiber of the 1 x 2 polarization-maintaining optical fiber coupler (7) is connected with a photoelectric detector on a bias voltage control board of the electro-optical modulator and is used for extracting and feeding back the modulated chirped pulse optical signal;
the first optical fiber polarization beam splitter (8) is used for splitting the optical signal into light with X and Y polarization directions;
the erbium-doped optical fiber amplifier (9) is used for amplifying the signal light generated by modulation and meeting the requirement of long-distance detection;
the optical fiber filter (10) is used for carrying out band-pass filtering on the optical signal amplified by the erbium-doped optical fiber amplifier and eliminating ASE noise;
the optical fiber circulator (11) inputs the detected scattered chirped pulse light into the sensing optical fiber and inputs the backscattered chirped pulse light into the demodulation optical path;
the sensing optical fiber (12) is used for transmitting and detecting a scattered chirped pulse optical signal and a back scattered chirped pulse optical signal and sensing a to-be-measured value;
the 2 x 2 optical fiber coupler (13) is used for combining the reference chirped pulse light and the backscattered chirped pulse light in the sensing optical fiber to generate interference;
the second optical fiber polarization beam splitter (14) is used for splitting one path of interference optical signal output by the 2X 2 optical fiber coupler into light in X and Y polarization directions;
the third optical fiber polarization beam splitter (15) is used for splitting the other path of interference optical signal output by the 2X 2 optical fiber coupler into light in X and Y polarization directions;
the X polarization direction balance photoelectric detector (16) is used for converting an X component part of an optical interference signal generated by the reference chirped pulse light and the backscattered chirped pulse light in the sensing optical fiber into an electric signal;
the Y polarization direction balance photoelectric detector (17) is used for converting a Y component part of an optical interference signal generated by the reference chirped pulse light and the back scattering chirped pulse light in the sensing optical fiber into an electric signal;
the data acquisition card (18) is used for acquiring and receiving the voltage analog signal converted by the balanced photoelectric detector;
and the processing unit (19) is used for controlling signal generation and signal reception, receiving and demodulating signals of the photoelectric detector and obtaining phase, amplitude and frequency information of the position of the sensing optical fiber acted by sound waves, and the implementation form comprises a computer and an embedded computing system.
2. The distributed optical fiber acoustic sensing method based on digital double-chirp pulse modulation, which is realized by the distributed optical fiber acoustic sensing device based on digital double-chirp pulse modulation according to claim 1, is used for long-distance distributed acoustic detection, and is characterized by comprising the following specific processes:
first, the light frequency emitted by the light source is omega0The continuous laser light enters a dual-polarization four-parallel Mach-Zehnder electro-optic modulator after passing through a polarization-maintaining optical fiber isolator; two arbitrary waveform generators, namely an arbitrary waveform generator for driving in the X polarization direction and the Y polarization direction, respectively generate chirp pulse digital signals with the same linear chirp range and the same frequency sweeping rate, and respectively load the chirp pulse digital signals into the X polarization direction and the Y polarization direction of the dual-polarization four-parallel Mach-Zehnder electro-optic modulator; the chirp pulse light signal in the X polarization direction is used as a detection light pulse, and the chirp pulse light signal in the continuous equal sweep frequency range in the Y polarization direction is used as a reference light;
secondly, dividing the chirped pulse light signal modulated by the dual-polarization four-parallel Mach-Zehnder electro-optic modulator into two parts through a 1-to-2 polarization-maintaining optical fiber coupler, wherein one path of output optical fiber is connected with a photoelectric detector on a bias control board of the electro-optic modulator and is used for extracting and feeding back the modulated chirped pulse light signal so as to keep the chirped pulse light signal in a stable working state for a long time; the other path of the chirped pulse light signal is split into an X polarization direction and a Y polarization direction through a first optical fiber polarization beam splitter, the chirped pulse light signal in the X polarization direction as a detection light pulse signal is amplified by an erbium-doped optical fiber amplifier, is injected into a sensing optical fiber after passing through an optical fiber filter and an optical fiber circulator, and is subjected to backward Rayleigh scattering in passing optical fibers, and the backward scattered chirped pulse light returns to a demodulation optical path along the optical fibers; the back scattering chirp pulse light containing the linear frequency sweep light used for demodulating phase information phi (t) and for demodulating optical frequency information I (omega) is subjected to mixed interference with the chirp pulse light signal in the continuous equal frequency sweep range of the Y polarization direction;
thirdly, outputting the backscattered chirped pulse light signal and the local reference chirped pulse light signal after interference in a 2X 2 optical fiber coupler, wherein one path of interference light signal is divided into light in X and Y polarization directions by a second optical fiber polarization beam splitter, and the other path of interference light signal is divided into light in X and Y polarization directions by a third optical fiber polarization beam splitter; the X component part and the Y component part of the interference signal are respectively converted into electric signals through an X polarization direction balancing photoelectric detector and a Y polarization direction balancing photoelectric detector, fast Fourier transform is respectively carried out on the two paths of signals to obtain FFT (X) signals and FFT (Y) signals, and each position in the sensing optical fiber is sequentially selected by using a moving window; then the distance domain information FFT (X) of the ith section of the sensing optical fiber selected by using the moving windowi) And FFT (Y)i) Performing an inverse Fourier transform to the optical frequency domain to obtain a corresponding XiAnd YiAnd summing the two to obtain the sum at t1Rayleigh scattering spectral information S (t) at time1)＝Xi+YiRemoving the direct current term; at the next time t2Calculating and obtaining Rayleigh scattering spectrum information S (t) at the same position of the sensing optical fiber according to the first two steps2)＝Xi+YiFor S (t)1) And S (t)2) Performing cross-correlation operation to obtain a cross-correlation coefficient and a noise level of a correlation diagram, and obtaining whether the sensing optical fiber has an acoustic wave action and an acoustic wave intensity at the position according to the cross-correlation peak coefficient and the noise level of the correlation diagram;
step four, calculating the spatial resolution of the system
Wherein tau is the chirp pulse width, and gamma is the chirp pulse scanning speed; the detection of the vibration frequency, amplitude and phase information of the sound source is realized through a phase extraction algorithm; the spatial resolution is determined by the frequency sweep range of the chirped pulse and is inversely related to the frequency sweep range.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810012818.3A CN108286992B (en) | 2018-01-06 | 2018-01-06 | Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation |
| PCT/CN2018/084084 WO2019134302A1 (en) | 2018-01-06 | 2018-04-23 | Distributed fiber-optical acoustic sensing device and method based on digital dual-chirped pulse modulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810012818.3A CN108286992B (en) | 2018-01-06 | 2018-01-06 | Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108286992A CN108286992A (en) | 2018-07-17 |
| CN108286992B true CN108286992B (en) | 2020-04-17 |
Family
ID=62834944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810012818.3A Active CN108286992B (en) | 2018-01-06 | 2018-01-06 | Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN108286992B (en) |
| WO (1) | WO2019134302A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110220540A (en) * | 2019-05-10 | 2019-09-10 | 中国船舶重工集团公司第七一五研究所 | A kind of detection light generation system applied to distributive fiber optic strain demodulation |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109088670B (en) * | 2018-08-10 | 2019-12-24 | 华中科技大学 | Method and system for determining sound wave signal |
| CN109217919A (en) * | 2018-11-01 | 2019-01-15 | 哈尔滨工业大学 | Based on the matched phase sensitivity type optical time domain reflectometer in time domain-airspace and measurement method |
| CN110108346B (en) * | 2019-04-22 | 2021-05-04 | 中国科学院上海光学精密机械研究所 | Optical fiber vibration sensor based on delay phase modulation chirp pulse pair |
| CN110864797B (en) * | 2019-11-13 | 2023-10-31 | 天津大学 | Differential COTDR distributed acoustic sensing device and method for heterogeneous double-sideband chirped pulses |
| CN113218494A (en) * | 2020-01-21 | 2021-08-06 | 中国科学院上海光学精密机械研究所 | Distributed optical fiber acoustic sensing system and signal processing method |
| CN111609919B (en) * | 2020-06-09 | 2021-06-01 | 重庆大学 | Optical fiber distributed vibration and loss simultaneous detection system |
| CN111609875B (en) * | 2020-06-10 | 2021-12-28 | 电子科技大学 | Digital domain adjustable distributed optical fiber sensing system and method based on chirp continuous light |
| CN112713929B (en) * | 2020-12-02 | 2022-02-18 | 广东工业大学 | Optical time domain reflectometer based on chirped pulses |
| CN112532337B (en) * | 2020-12-07 | 2022-10-18 | 无锡科晟光子科技有限公司 | Distributed high-precision optical fiber vibration invasion and online monitoring detector |
| CN112636837B (en) * | 2020-12-21 | 2022-10-18 | 中国科学院半导体研究所 | Dual-waveband dual-chirp microwave signal generation and transmission device and method |
| CN112880711B (en) * | 2021-01-18 | 2023-07-04 | 合肥工业大学 | Distributed optical fiber sensing method and system based on double pulse modulation |
| CN112985639B (en) * | 2021-02-06 | 2022-02-15 | 电子科技大学 | Distributed optical fiber sensing method based on chirp removal and time domain sub-chirp pulse extraction |
| CN113206705B (en) * | 2021-03-25 | 2022-06-21 | 中国人民解放军空军工程大学 | Self-interference elimination method based on optical fiber dispersion effect and digital algorithm |
| CN113447110B (en) * | 2021-06-10 | 2022-08-30 | 天津大学 | Distributed optical fiber vibration sensing system and phase carrier demodulation method thereof |
| CN113541787B (en) * | 2021-06-23 | 2022-06-17 | 中国人民解放军空军工程大学 | Functional flexible photonics auxiliary frequency measuring method and device |
| CN113810098B (en) * | 2021-07-20 | 2022-09-16 | 广东工业大学 | Optical time domain reflectometer based on double-sideband chirp pulse modulation |
| CN113810099B (en) * | 2021-08-20 | 2022-10-14 | 广东工业大学 | Optical time domain reflectometer based on asymmetric double-sideband chirped pulse modulation |
| CN114279569B (en) * | 2021-11-17 | 2023-10-03 | 中山大学 | Feedback control method for multi-carrier tracking detection light interference type sensor spectrum |
| US20230283385A1 (en) * | 2022-02-18 | 2023-09-07 | Nec Laboratories America, Inc | Data transmission-tolerant distributed acoustic sensing using chirped-pulses with time-domain roll off |
| CN114878141B (en) * | 2022-04-22 | 2023-08-04 | 成都飞机工业（集团）有限责任公司 | Airborne optical cable connection fault positioning method and system |
| CN115549790B (en) * | 2022-11-29 | 2023-03-24 | 湖北经济学院 | Optical signal modulation system and transmission system of modulated optical signal generated by same |
| CN115790814B (en) * | 2023-01-05 | 2023-05-23 | 之江实验室 | Optical fiber vibration detection system and method thereof |
| CN116907627B (en) * | 2023-09-13 | 2023-12-19 | 之江实验室 | Optical path difference auxiliary-based large dynamic range distributed phase sensing method and device |
| CN117109646B (en) * | 2023-10-25 | 2024-02-23 | 杭州奕力科技有限公司 | Sensing demodulation method of linear chirped fiber grating |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102759371A (en) * | 2012-07-19 | 2012-10-31 | 南京大学 | COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer |
| CN105628063A (en) * | 2015-12-31 | 2016-06-01 | 中国人民解放军国防科学技术大学 | Brillouin light time domain analysis device and method based on dual-wavelength polarization orthogonal light |
| CN107289978A (en) * | 2017-06-09 | 2017-10-24 | 南京大学 | A kind of system and method for the survey disturbance based on POTDR |
| CN107402029A (en) * | 2017-08-08 | 2017-11-28 | 电子科技大学 | The method and system of distributing optical fiber sensing measuring speed are improved using orthogonal signalling |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020044712A1 (en) * | 2000-10-16 | 2002-04-18 | Henry Hung | Apparatus for adding wavelength components in wavelength division multiplexed optical signals using mach-zehnder interferometer |
| US7499176B2 (en) * | 2007-02-13 | 2009-03-03 | Future Fibre Technologies Pty Ltd | Apparatus and method for using a counter-propagating signal method for locating events |
| JP5412209B2 (en) * | 2009-08-07 | 2014-02-12 | 日本電信電話株式会社 | Optical frequency domain reflection measurement method and optical frequency domain reflection measurement apparatus |
| CN102636196B (en) * | 2012-04-09 | 2014-09-17 | 天津大学 | Distributed disturbance sensor on basis of Rayleigh scattering spectrum related coefficient and demodulating method thereof |
| CN104596632A (en) * | 2013-10-31 | 2015-05-06 | 上海华魏光纤传感技术有限公司 | Distributed optical fiber vibration sensor for enhancing long-distance detection, and method of distributed optical fiber vibration sensor |
| CN103595482B (en) * | 2013-11-08 | 2015-12-30 | 武汉邮电科学研究院 | Be applicable to bias control device and the method for dual-polarization I/Q modulator |
| CN105092014B (en) * | 2015-05-12 | 2018-05-25 | 天津大学 | Distribution type fiber-optic acoustic detection device and detection method based on Wave beam forming |
| CN107014409B (en) * | 2017-03-26 | 2019-05-28 | 天津大学 | A kind of long range optical frequency domain reflection-based optical fiber Distributed Multi destabilization sensing method |
-
2018
- 2018-01-06 CN CN201810012818.3A patent/CN108286992B/en active Active
- 2018-04-23 WO PCT/CN2018/084084 patent/WO2019134302A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102759371A (en) * | 2012-07-19 | 2012-10-31 | 南京大学 | COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer |
| CN105628063A (en) * | 2015-12-31 | 2016-06-01 | 中国人民解放军国防科学技术大学 | Brillouin light time domain analysis device and method based on dual-wavelength polarization orthogonal light |
| CN107289978A (en) * | 2017-06-09 | 2017-10-24 | 南京大学 | A kind of system and method for the survey disturbance based on POTDR |
| CN107402029A (en) * | 2017-08-08 | 2017-11-28 | 电子科技大学 | The method and system of distributing optical fiber sensing measuring speed are improved using orthogonal signalling |
Non-Patent Citations (3)
| Title |
|---|
| COTDR技术在地铁隧道施工安全监测中的应用;刘敏杰;《交通科技》;20161231(第6期);第55-56页 * |
| 偏振光时域反射技术对多点扰动检测的研究进展;王峰等;《集成技术》;20160930;第5卷(第5期);第1-10页 * |
| 基于双平行马赫曾德尔调制器和受激布里渊散射效应的十倍频毫米波信号生成;耿红建等;《光电子.激光》;20150430;第26卷(第4期);第695-699页 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110220540A (en) * | 2019-05-10 | 2019-09-10 | 中国船舶重工集团公司第七一五研究所 | A kind of detection light generation system applied to distributive fiber optic strain demodulation |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019134302A1 (en) | 2019-07-11 |
| CN108286992A (en) | 2018-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108286992B (en) | Distributed optical fiber acoustic sensing device and method based on digital double-chirp pulse modulation | |
| US20220283021A1 (en) | Differential cotdr distributed acoustic sensing device and method based on heterogeneous double-sideband chirped-pulses | |
| CN108507663B (en) | Distributed optical fiber acoustic sensing device and method based on dual-polarization dual-sideband modulation | |
| CN107576392B (en) | A kind of identification device of the chaotic laser light exocoel time delay based on coherent field | |
| CN108507662B (en) | Optical fiber distributed sensing method and device based on multi-wavelength double-optical pulse | |
| CN111157101A (en) | Weak grating array distributed vibration sensing system and method | |
| CN102571200A (en) | Method and device of multi-frequency detecting-light coherent light time-domain reflectometer | |
| CN105606196A (en) | High-frequency vibration measurement distributed fiber sensing system based on frequency division multiplexing technology | |
| CN101893475B (en) | A kind of distributed optical fiber vibration sensing system based on fiber delay line | |
| CN102412894A (en) | Multifrequency probe light time division multiplexing coherent light time domain reflectometer method and apparatus thereof | |
| CN103837165A (en) | Brillouin time-domain analysis system based on Brillouin laser and automatic heterodyne detection | |
| CN111928938A (en) | Long-distance distributed optical fiber vibration detection system | |
| CN115913378B (en) | Common-frequency shared optical fiber communication sensing integrated system | |
| CN114279476B (en) | Distributed optical fiber sensing device based on phase type chaotic laser and measuring method thereof | |
| CN113607277B (en) | Demodulation method of narrow linewidth laser linewidth measurement system | |
| Zhao et al. | Interferometric fiber-optic hydrophone system based on linear frequency modulation | |
| CN218728071U (en) | Microseism monitoring system in shale gas hydraulic fracturing | |
| CN115235367B (en) | High-precision double-frequency optical frequency domain reflectometer with large strain measurement range | |
| CN117968823B (en) | Distributed optical fiber sound sensing device and sound detection method | |
| CN112683312B (en) | Brillouin optical time domain reflectometer based on multimode optical fiber | |
| CN112033521B (en) | Local noise self-filtering hybrid optical fiber vibration sensing system | |
| Li et al. | Signal to Noise Ratio Enhancement in Multimode Fiber Based Phase Sensitive Optical Time Domain Reflectometry | |
| Xiao et al. | Fading Suppression and Enhanced Signal-to-noise Ratio in Multicore Fiber Integrated Ф-OTDR System | |
| Xu et al. | Research on Bandwidth suppression based on dual-channel time-sharing detection | |
| Cai et al. | Suppression of fading in Ф-OTDR systems based on phase-modulated optical frequency combs |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |