CN111750912A - High-spatial-resolution high-capacity grating array OTDR differential demodulation method and system - Google Patents
High-spatial-resolution high-capacity grating array OTDR differential demodulation method and system Download PDFInfo
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- 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
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- G01D5/35367—Sensor working in reflection using reflected light other than backscattered to detect the measured quantity
Abstract
The invention provides a high-spatial-resolution large-capacity grating array OTDR differential demodulation method, which comprises the following steps of: modulating continuous sweep frequency light emitted by a light source into pulse light, and emitting the pulse light with different pulse widths in two continuous periods, wherein the difference values of adjacent pulse widths are equal; the pulse light is reflected by the high-density fiber bragg grating array to be detected, the reflected light is converted into an electric signal, and sampling is carried out; carrying out differential operation on sampling data of pulse light with pulse widths of two adjacent periods every time the pulse width is stepped, and respectively obtaining a reflection signal of each grating; and if the stepping value is N, obtaining N groups of reflection signals by each grating, and carrying out N-order averaging on the N groups of reflection signals to be used as the final reflection signal of each grating. The invention can improve the spatial resolution of the demodulation signal of the OTDR system under the condition of not adding any device.
Description
Technical Field
The invention relates to the field of fiber grating sensing, in particular to an OTDR differential demodulation method and system capable of providing high spatial resolution for a large-capacity grating array sensing system.
Background
A large-capacity grating array sensing system is a novel optical fiber sensing system which is rapidly developed in recent years, tens of thousands of sensing gratings can be continuously written on one optical fiber, the minimum writing interval reaches 10 cm., but the space resolution of the current demodulation by the OTDR technology cannot reach the level of 10cm, the space resolution of the OTDR demodulation system is related to two indexes, namely the pulse width of a light source, and the speed of light propagating in the optical fiber is 2.0 × 108m/s, the spatial resolution reaches 10cm, and the pulse width must reach 0.1m × 2/2.0 × 108The m/s is 1ns, limited by the current hardware level, the rising edge of an optical pulse is generally about 2ns, the pulse width can only reach 5-10 ns, if the pulse width reaches 1ns, the rising edge time must be about 0.1ns, a very high hardware bandwidth and a very fast response speed are required, and thus the cost is greatly increased. Another factor influencing the spatial resolution is the sampling frequency, according to the nyquist sampling law, if a signal with a pulse width of 1ns needs to be accurately restored, the sampling frequency is at least 2 times as high, namely 2/1ns is approximately equal to 2GHz, and the current data acquisition card with the frequency of more than 2GHz is relatively common and has moderate price. Therefore, the main factor that currently limits the spatial resolution of the OTDR demodulation system is the pulse width of the light source, so that the invention of an OTDR demodulation method with low cost and high spatial resolution is urgent.
Disclosure of Invention
The invention aims to improve the spatial resolution of the fiber grating array demodulation under the condition of not adding any device.
The technical scheme adopted by the invention for achieving the purpose is as follows:
a high-spatial-resolution large-capacity grating array OTDR differential demodulation method is provided, which comprises the following steps:
modulating continuous sweep frequency light emitted by a light source into pulse light, and emitting the pulse light with different pulse widths in two continuous periods, wherein the difference values of adjacent pulse widths are equal;
the pulse light is reflected by the high-density fiber bragg grating array to be detected, the reflected light is converted into an electric signal, and sampling is carried out;
carrying out differential operation on sampling data of pulse light with pulse widths of two adjacent periods every time the pulse width is stepped, and respectively obtaining a reflection signal of each grating;
and if the stepping value is N, obtaining N groups of reflection signals by each grating, and carrying out N-order averaging on the N groups of reflection signals to be used as the final reflection signal of each grating.
According to the technical scheme, the high-density fiber grating to be detected comprises a grating to be detected and a light channel to be detected, wherein the distance between the grating to be detected and the light channel to be detected is 0.1m, the grating to be detected is a semi-transparent and semi-reflective optical sensor, light with the wavelength coincident with that of the grating is reflected after wide-spectrum light enters, and light with other wavelengths can penetrate through the grating.
According to the technical scheme, one pulse width of adjacent periods is i, the other pulse width is j, and the difference value of the pulse widths is 1ns, so that the pulse with the pulse width i acquires data:
the first sample data is denoted as D1,iThe information carried by it is a raster G1～G10The sum of the reflected light intensities;
the second sample data is denoted as D2,iWith the first data D1,iAt intervals of 0.5ns, the information carried by the grating is grating G1～G10+0.05m；
By D1,i、D2,iTwo sampling points restore G1～G10The reflection spectrum of each grating;
the third sample data is denoted as D3,iWith the first data D1,iAt intervals of 1ns, the information carried by the grating is grating G2～G11Sum of reflected light intensity, which is equal to D4,iReduction to G2～G11The reflection spectrum of each grating;
……
among the data collected for the pulse with pulse width j:
the first sample data is denoted as D1,jThe information carried by it is a raster G1～G11Sum of reflected light intensity, which is equal to D2,jReduction to G1～G11The reflection spectrum of each grating;
the third sample data is denoted as D3,jThe information carried by it is a raster G2～G12Sum of reflected light intensity, which is equal to D4,jReduction to G2～G12The reflection spectrum of each grating;
……
reflection signal G of nth gratingnFrom D2n-1,j-D2n,i，D2n,j-D2n+1,iBoth data are restored.
In connection with the above technical scheme, when the step value is N, N sets of differential arrays (D) can be obtained2n-1,j-D2n,i，D2n,j-D2n+1,i) Obtaining N groups G according to the m groups of difference arraysnTo GnAnd carrying out N-order averaging.
The invention also provides a system of the large-capacity grating array OTDR differential demodulation method with spatial resolution, which comprises the following steps:
a light source emitting continuous sweep light;
the pulse modulation unit modulates the continuous sweep frequency light into pulse light which emits different pulse widths in two continuous periods, and the difference values of the adjacent pulse widths are the same;
the high-density fiber grating array to be detected comprises a grating to be detected and an optical channel to be detected, wherein the grating to be detected is a semi-transparent and semi-reflective optical sensor, wide-spectrum light is reflected after entering the optical sensor, light with the wavelength coincident with that of the grating is reflected, light with other wavelengths is transmitted, and the optical channel to be detected is connected with the grating to be detected;
the photoelectric conversion module is used for converting an optical signal returned by the optical channel to be detected into an electric signal for the data acquisition module to acquire;
the data acquisition module comprises an A/D sampling chip and an FPGA control chip, wherein the A/D sampling chip performs A/D conversion on an analog signal output by the photoelectric conversion module and then is acquired by the FPGA control chip, and the FPGA control chip performs difference on data acquired under different pulse widths and uploads the data to the data processing module;
and the data processing module is used for carrying out difference on the data acquired under different pulse widths to obtain a high-spatial resolution signal, and carrying out filtering demodulation on the signal to obtain the final grating wavelength.
According to the technical scheme, the wavelength of the grating to be measured does not exceed the spectral coverage range of the light source.
In connection with the above technical solution, the photoelectric conversion module includes a photoelectric conversion probe and an operational amplifier.
According to the technical scheme, data are transmitted between the data acquisition module and the data processing module through the USB3.0 high-speed interface.
According to the technical scheme, the difference value of the lengths of the adjacent pulse widths is 1ns of optical path, and the sampling frequency is not lower than 2 GHz.
The invention has the following beneficial effects: the invention can obtain the demodulation signal with ultrahigh resolution of the OTDR system under the condition of lower hardware cost without adding any device, and can obtain the demodulation signal with any spatial resolution of the OTDR system through different pulse width combinations, thereby providing possibility for a low-cost scheme of detecting with ultrahigh spatial resolution, such as temperature monitoring of a storage battery electrode.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a system block diagram of a large-capacity grating array OTDR differential demodulation system with spatial resolution according to an embodiment of the present invention.
Fig. 2 is a flowchart of a large-capacity grating array OTDR differential demodulation method of spatial resolution according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of sampling at two different pulse widths according to the present invention.
In fig. 1, a light source 1, a pulse modulation unit 2, a high-density grating 3 to be detected, a photoelectric conversion module 4, a data acquisition module 5, and a data processing module 6.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Fig. 1 shows a block diagram of an OTDR differential demodulation system of a large-capacity grating array with spatial resolution according to an embodiment of the present invention. The system comprises a light source 1, a pulse modulation unit 2, a high-density grating 3 to be detected, a photoelectric conversion module 4, a data acquisition module 5 and a data processing module 6.
The light source 1 modulates continuous light into pulsed light by the pulse modulation unit 2 by emitting continuous frequency-sweeping light, wherein the width of the pulsed light is controlled by the unit, and two continuous periods emit pulsed light with different pulse widths, for example, one period of the pulsed light is 10ns, and the other period of the pulsed light is 11 ns. Pulse light passes through the high-density grating 3 to be detected, the grating interval of the high-density grating 3 to be detected is 0.1m, the pulse light enters the photoelectric conversion module 4 after being reflected by the grating, the module converts a returned optical signal into an electric signal and is collected by the data collection module 5, collected data are transmitted to the data processing module 6 through the USB3.0 high-speed interface, and the data collected in two periods are subjected to differential demodulation by the module to obtain final data.
The light source 1 provides an original continuous frequency sweeping light signal for the system, and the spectral bandwidth is 8nm in the embodiment of the invention, and the output spectral range of the light source should not exceed the modulation range of the pulse modulation unit 2.
The pulse modulation unit 2 provides a pulse light signal for the system, modulates continuous light into pulse light with the width of several ns, and changes the pulse widths of two continuous demodulation periods through program control, and the difference value of the two pulse widths determines the spatial resolution of the system.
The high-density grating 3 to be measured is composed of a grating to be measured with a spacing of 0.1m and a light channel to be measured, wherein the grating to be measured is a semi-transparent semi-reflective optical sensor, light with the wavelength coincident with that of the grating is reflected after the wide-spectrum light enters, and light with other wavelengths can penetrate through the grating. The light channel to be measured can be connected with the grating to be measured, and the wavelength of the grating to be measured cannot exceed the spectral coverage of the light source 1.
The photoelectric conversion module 4 converts the optical signal returned by the channel to be detected into an electric signal for the data acquisition module 5 to acquire. The photoelectric conversion module 4 includes devices such as a photoelectric conversion probe and an operational amplifier.
The data acquisition module 5 comprises an A/D sampling chip and an FPGA control chip, the A/D chip performs A/D conversion on analog signals output by the photoelectric conversion module 4 and then is acquired by the FPGA chip, the FPGA performs difference on the acquired data under different pulse widths, the acquisition frequency is not lower than 2GHz, and the acquired data are uploaded to the data processing module 6.
The data processing module 6 performs difference on the data acquired under different pulse widths to obtain a signal with high spatial resolution, and performs filtering demodulation on the signal to obtain the final wavelength.
The method for realizing the high-spatial-resolution large-capacity grating array OTDR differential demodulation by using the system comprises the following steps as shown in FIG. 2:
s1, modulating continuous sweep frequency light emitted by a light source into pulse light, and emitting the pulse light with different pulse widths in two continuous periods, wherein the difference of adjacent pulse width lengths is 1 ns;
s2, reflecting the pulse light by the high-density fiber bragg grating array to be detected, converting the reflected light into an electric signal, and sampling, wherein the sampling frequency is not lower than 2 GHz;
s3, carrying out differential operation on the sampling data of the pulse light with the pulse width of two adjacent periods every time the pulse width is stepped, and respectively obtaining the reflection signal of each grating;
and S4, if the stepping value is N, obtaining N groups of reflection signals by each grating, and carrying out N-order averaging on the N groups of reflection signals to obtain the final reflection signal of each grating.
Determining N +1 pulse width values T according to the step value N1～Tn+1The difference between the pulse widths is △ T if T is the same1Is 10ns, then T2Is 10ns + △ T, … … Tn+110ns + N △ t. target spatial resolution x △ t × 108m (the speed of the light propagating in the optical fiber is 2.0 × 108m/s) when △ T is 1ns, T1Is 10ns, then T2Is 11ns, … … Tn+1Is (10+ N) ns, the target is nullThe intermediate resolution x is 0.1 m.
In an embodiment of the present invention, the pulse width of the pulsed light is controlled by a frequency synthesis clock generation chip AD9833BRMZ, the chip can obtain an ns-level pulse signal through the difference of high-frequency clock signals, two periods of the system respectively emit optical pulses with different pulse widths, for example, 11ns and 10 ns. modulated pulse signals enter a high-density grating 3 to be measured, and the high-density grating 3 to be measured reflects an optical signal, as shown in fig. 3, when the light with 11ns pulse width is reflected back to the photoelectric probe through the grating, the range of the carried grating signal is 11 × 10-9s×2×108The m/s × 0.5.5 is 1.1m, namely 11 gratings are covered, the range corresponding to the pulse width of 10ns is 1m, namely 10 gratings are covered, the reflected signal enters the photoelectric module 4 to convert the optical signal into an electric signal and is subjected to A/D acquisition by the acquisition module 5, the acquired data is stored in an FPGA chip and is uploaded to the data processing module 6, the two groups of signals are subjected to subtraction, namely the signals covering the 11 gratings are subtracted from the signals covering the 10 gratings, signals of 1 grating can be obtained, the spatial resolution reaches 0.1m, and finally the signals are subjected to filtering demodulation to obtain the final wavelength.
In this embodiment, a tunable narrow-band laser is used as a light source. A switch type semiconductor SOA ring laser is selected as a pulse modulator, and a frequency synthesis clock generation chip AD9833BRMZ is selected as a driving chip. The high-density grating to be detected is a self-made grating array, an intensive grating array sensing optical cable is manufactured by adopting a unique and internationally advanced on-line fiber grating inscription technology of a drawing tower in China, a single sensing optical cable can be used for continuously inscribing tens of thousands of grating measuring points in an industrial automatic manner, the consistency is good, and the mechanical strength is high; the photoelectric conversion module adopts a self-developed high-bandwidth photoelectric conversion circuit.
The system work flow is as follows: the tunable narrow-band laser 1 emits continuous light of varying wavelength. The method comprises the steps of entering a pulse width modulation system 2 consisting of a switch type semiconductor SOA ring laser and a frequency synthesis clock generating chip, automatically generating pulse sequences with different pulse widths by the frequency synthesis clock generating chip according to expected spatial resolution and stepping values set by a user, and selecting a narrow pulse width sequence as far as possible as the pulse width is wider and the rising edge time is longer. For example, a signal with a spatial resolution of 0.1m is expected to be obtained, and the step value is 5 times, then the frequency synthesis clock generation chip will generate a pulse sequence of 10 ns-15 ns, the sampling frequency is 2GHz, that is, 0.5ns, and one data is acquired, and in the data acquired by the 10ns pulse:
the first sample data is denoted as D1,10The information carried by the grating is 1-10 (G)1～G10) The sum of the reflected light intensities.
The second sample data is denoted as D2,10With the first data D1,10At an interval of 0.5ns, the information carried by the grating is 1-10 (G)1～G10)+0.5×10-9s×2×108m/s × 0.5 ═ gratings 1-10 (G)1～G10) +0.05m of information carried;
by D1,10、D2,10G can be recovered by two sampling points1～G10The reflection spectrum of each grating, e.g. by averaging the first sampled data and the second sampled data, is taken as G1～G10The reflection spectrum of each grating.
By analogy with that
The third sample data is denoted as D3,10With the first data D1,10At intervals of 1ns, the information carried by the grating is 1-10 (G)1～G10)+1×10-9s×2×108m/s × 0.5 ═ gratings 1-10 (G)1～G10) +0.1m ═ gratings 2-11 (G)2～G11) Sum of reflected light intensity, which is equal to D4,10Can reduce to G2～G11The reflection spectrum of each grating.
In the data collected by the 11ns pulse:
the first sample data is denoted as D1,11The information carried by the grating is 1-11 (G)1～G11) Sum of reflected light intensity, which is equal to D2,11Can reduce to G1～G11The reflection spectrum of each grating.
The third sample data is denoted as D3,11The information carried by the grating is 2-12 (G)2～G12) Reflected backSum of light intensity, it and D4,11Can reduce to G2～G12The reflection spectrum of each grating.
……
To sum up, the reflection signal G of the nth gratingnCan be composed of2n-1,11-D2n,10，D2n,11-D2n+1,10The two data are restored … …, and if the step value is 5, 5 sets of difference arrays (D) are obtained2n-1,11-D2n,10，D2n,11-D2n+1,10) Where n is 1,2,3,4,5 groups G can be obtained from 5 groups of difference arraysnTo Gn5-order averaging can improve the signal-to-noise ratio of the final result
And (4) doubling.
In addition, it is also possible to obtain demodulated signals of any spatial resolution of the OTDR system by different pulse width combinations, such as pulse width combinations spaced 2ns apart, but with a reduced spatial resolution compared to pulse width combinations spaced 1ns apart.
The invention can obtain the demodulation signal with ultrahigh resolution of the OTDR system under the condition of lower hardware cost without adding any device. The invention can obtain the demodulation signal with any space resolution of the OTDR system through different pulse width combinations. The invention provides the possibility of a low-cost solution for ultra-high spatial resolution detection, such as temperature monitoring of battery electrodes.
It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.
Claims (9)
1. A high-spatial-resolution large-capacity grating array OTDR differential demodulation method is characterized by comprising the following steps:
modulating continuous sweep frequency light emitted by a light source into pulse light, and emitting the pulse light with different pulse widths in two continuous periods, wherein the difference values of adjacent pulse widths are equal;
the pulse light is reflected by the high-density fiber bragg grating array to be detected, the reflected light is converted into an electric signal, and sampling is carried out;
carrying out differential operation on sampling data of pulse light with pulse widths of two adjacent periods every time the pulse width is stepped, and respectively obtaining a reflection signal of each grating;
and if the stepping value is N, obtaining N groups of reflection signals by each grating, and carrying out N-order averaging on the N groups of reflection signals to be used as the final reflection signal of each grating.
2. The high-spatial-resolution high-capacity optical grating array OTDR differential demodulation method of claim 1, wherein said high-density optical fiber grating to be measured includes a grating to be measured and an optical channel to be measured, the distance between which is 0.1m, wherein the grating to be measured is a half-transparent and half-reflective optical sensor, the light of the wide-spectrum light that is coincident with the wavelength of the grating is reflected after entering, and the light of other wavelengths is transmitted.
3. The OTDR differential demodulation method of large capacity grating array with spatial resolution of claim 1, characterized in that, if one pulse width of adjacent periods is i, another pulse width is j, and the difference of pulse widths is 1ns, then the pulse with pulse width i acquires data that:
the first sample data is denoted as D1,iThe information carried by it is a raster G1～G10The sum of the reflected light intensities;
the second sample data is denoted as D2,iWith the first data D1,iAt intervals of 0.5ns, the information carried by the grating is grating G1～G10+0.05m；
By D1,i、D2,iTwo sampling points restore G1～G10The reflection spectrum of each grating;
the third sample data is denoted as D3,iWith the first data D1,iAt intervals of 1ns, the information carried by the grating is grating G2～G11Sum of reflected light intensity, which is equal to D4,iReduction to G2～G11The reflection spectrum of each grating;
……
among the data collected for the pulse with pulse width j:
the first sample data is denoted as D1,jThe information carried by it is a raster G1～G11Sum of reflected light intensity, which is equal to D2,jReduction to G1～G11The reflection spectrum of each grating;
the third sample data is denoted as D3,j，The information it carries is a grating G2～G12Sum of reflected light intensity, which is equal to D4,jReduction to G2～G12The reflection spectrum of each grating;
……
reflection signal G of nth gratingnFrom D2n-1,j- D2n,i， D2n,j- D2n+1,iBoth data are restored.
4. A spatial resolution high capacity grating array OTDR differential demodulation method according to claim 3, wherein when the step value is N, m sets of differential arrays (D) are obtained2n-1,j- D2n,i， D2n,j- D2n+1,i) Obtaining N groups G according to the N groups of difference arraysnTo GnAnd carrying out N-order averaging.
5. A system of large capacity grating array OTDR differential demodulation method based on spatial resolution of claim 1, characterized by comprising:
a light source emitting continuous sweep light;
the pulse modulation unit modulates the continuous sweep frequency light into pulse light which emits different pulse widths in two continuous periods, and the difference values of the adjacent pulse widths are the same;
the high-density fiber grating array to be detected comprises a grating to be detected and an optical channel to be detected, wherein the grating to be detected is a semi-transparent and semi-reflective optical sensor, wide-spectrum light is reflected after entering the optical sensor, light with the wavelength coincident with that of the grating is reflected, light with other wavelengths is transmitted, and the optical channel to be detected is connected with the grating to be detected;
the photoelectric conversion module is used for converting an optical signal returned by the optical channel to be detected into an electric signal for the data acquisition module to acquire;
the data acquisition module comprises an A/D sampling chip and an FPGA control chip, wherein the A/D sampling chip performs A/D conversion on an analog signal output by the photoelectric conversion module and then is acquired by the FPGA control chip, and the FPGA control chip performs difference on data acquired under different pulse widths and uploads the data to the data processing module;
and the data processing module is used for carrying out difference on the data acquired under different pulse widths to obtain a high-spatial resolution signal, and carrying out filtering demodulation on the signal to obtain the final grating wavelength.
6. The system of claim 5, wherein the wavelength of the grating under test does not exceed the spectral coverage of the light source.
7. The system of claim 5, wherein the photoelectric conversion module comprises a photoelectric conversion probe and an operational amplifier.
8. The system of claim 5, wherein the data acquisition module and the data processing module transmit data through a USB3.0 high-speed interface.
9. The system according to any one of claims 5-8, wherein the difference between adjacent pulse widths is 1ns and the sampling frequency is not lower than 2 GHz.
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Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001041849A (en) * | 1999-08-02 | 2001-02-16 | Advantest Corp | Otdr measuring instrument |
| JP2005030890A (en) * | 2003-07-11 | 2005-02-03 | Toshiba Corp | Method and apparatus for measuring fiber bragg grating physical quantity |
| CN1661333A (en) * | 2004-02-25 | 2005-08-31 | 韩国科学技术院 | Physical quantity measuring method using brillouin optical fiber sensor |
| JP2007033183A (en) * | 2005-07-26 | 2007-02-08 | Shibaura Institute Of Technology | Method for measuring brillouin spectrum of optical fiber and apparatus using this method |
| EP1912049A1 (en) * | 2006-10-13 | 2008-04-16 | AT&T Corp. | Method and apparatus for acoustic sensing using multiple optical pulses |
| CN103808342A (en) * | 2014-03-05 | 2014-05-21 | 武汉理工大学 | High-speed demodulation method and device for high-capacity weak grating sensing network |
| CN106066203A (en) * | 2016-05-25 | 2016-11-02 | 武汉理工大学 | Distributed highly sensitive vibration-detection system based on ultrashort optical fiber optical grating array and method |
| CN106525091A (en) * | 2016-10-25 | 2017-03-22 | 华中科技大学 | Fiber grating array sensing demodulation system based on multi-wavelength pulse differential modulation |
| CN106525092A (en) * | 2016-11-03 | 2017-03-22 | 华南理工大学 | High-spatial resolution long-distance distributed optical fiber temperature strain sensing system |
| CN107835001A (en) * | 2017-10-27 | 2018-03-23 | 上海辰竹仪表有限公司 | Processing method, system, signal processing apparatus and the medium of pulse width modulation wave |
| CN108180930A (en) * | 2017-12-29 | 2018-06-19 | 武汉理工光科股份有限公司 | Long range arrayed optical fiber grating sensing demodulation method and device |
| CN109000694A (en) * | 2018-10-19 | 2018-12-14 | 武汉烽理光电技术有限公司 | Grating prepares on-line monitoring method and system |
| CN109506686A (en) * | 2018-12-19 | 2019-03-22 | 武汉理工光科股份有限公司 | A method of it improves entirely with optical fiber Grating examinations performance |
| CN110855371A (en) * | 2019-11-08 | 2020-02-28 | 武汉理工光科股份有限公司 | Method and system for improving optical fiber sensing detection spatial resolution |
-
2020
- 2020-06-23 CN CN202010582634.8A patent/CN111750912B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001041849A (en) * | 1999-08-02 | 2001-02-16 | Advantest Corp | Otdr measuring instrument |
| JP2005030890A (en) * | 2003-07-11 | 2005-02-03 | Toshiba Corp | Method and apparatus for measuring fiber bragg grating physical quantity |
| CN1661333A (en) * | 2004-02-25 | 2005-08-31 | 韩国科学技术院 | Physical quantity measuring method using brillouin optical fiber sensor |
| JP2007033183A (en) * | 2005-07-26 | 2007-02-08 | Shibaura Institute Of Technology | Method for measuring brillouin spectrum of optical fiber and apparatus using this method |
| EP1912049A1 (en) * | 2006-10-13 | 2008-04-16 | AT&T Corp. | Method and apparatus for acoustic sensing using multiple optical pulses |
| CN103808342A (en) * | 2014-03-05 | 2014-05-21 | 武汉理工大学 | High-speed demodulation method and device for high-capacity weak grating sensing network |
| CN106066203A (en) * | 2016-05-25 | 2016-11-02 | 武汉理工大学 | Distributed highly sensitive vibration-detection system based on ultrashort optical fiber optical grating array and method |
| CN106525091A (en) * | 2016-10-25 | 2017-03-22 | 华中科技大学 | Fiber grating array sensing demodulation system based on multi-wavelength pulse differential modulation |
| CN106525092A (en) * | 2016-11-03 | 2017-03-22 | 华南理工大学 | High-spatial resolution long-distance distributed optical fiber temperature strain sensing system |
| CN107835001A (en) * | 2017-10-27 | 2018-03-23 | 上海辰竹仪表有限公司 | Processing method, system, signal processing apparatus and the medium of pulse width modulation wave |
| CN108180930A (en) * | 2017-12-29 | 2018-06-19 | 武汉理工光科股份有限公司 | Long range arrayed optical fiber grating sensing demodulation method and device |
| CN109000694A (en) * | 2018-10-19 | 2018-12-14 | 武汉烽理光电技术有限公司 | Grating prepares on-line monitoring method and system |
| CN109506686A (en) * | 2018-12-19 | 2019-03-22 | 武汉理工光科股份有限公司 | A method of it improves entirely with optical fiber Grating examinations performance |
| CN110855371A (en) * | 2019-11-08 | 2020-02-28 | 武汉理工光科股份有限公司 | Method and system for improving optical fiber sensing detection spatial resolution |
Non-Patent Citations (3)
| Title |
|---|
| QIZHONG YAN ET.AL: "Coherent Φ-OTDR based on polarization-diversity integrated coherent receiver and heterodyne detection", 《2017 25TH OPTICAL FIBER SENSORS CONFERENCE》 * |
| TAO LIU ET.AL: "Simulation of the performance of phase-sensitive OTDR based on Ultra-weak FBG array using double pulses", 《2017 16TH INTERNATIONAL CONFERENCE ON OPTICAL COMMUNICATIONS AND NETWORKS》 * |
| 陶鑫等: "基于弱光栅阵列低成本大长周界系统及其报警机制", 《中国激光》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113654579A (en) * | 2021-08-26 | 2021-11-16 | 暨南大学 | Optical sensor digital demodulation device and method based on sweep frequency light source |
| CN113654579B (en) * | 2021-08-26 | 2024-01-09 | 暨南大学 | Optical sensor digital demodulation device and method based on sweep frequency light source |
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