CN101598574A - A kind of fiber-optic grating sensor - Google Patents
A kind of fiber-optic grating sensor Download PDFInfo
- Publication number
- CN101598574A CN101598574A CNA200810100061XA CN200810100061A CN101598574A CN 101598574 A CN101598574 A CN 101598574A CN A200810100061X A CNA200810100061X A CN A200810100061XA CN 200810100061 A CN200810100061 A CN 200810100061A CN 101598574 A CN101598574 A CN 101598574A
- Authority
- CN
- China
- Prior art keywords
- wavelength
- fiber
- light signal
- physical quantity
- grating
- 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.)
- Pending
Links
Images
Landscapes
- Optical Transform (AREA)
Abstract
The present invention relates to a kind of fiber-optic grating sensor, comprise light source, optical fiber, detector and the fiber grating that is used to monitor the physical quantity variation that is positioned at measurement point that is placed on the optical fiber, it is characterized in that: the detection light signal of light source output injects from the optical fiber input end, survey light wavelength not in the selectively acting wavelength band of fiber grating, and have the preset wavelength difference with the selectively acting wavelength, one when monitored physical quantity variation reaches certain value, be positioned at the preset wavelength difference that the selectively acting wavelength band of the fiber grating of measurement point has drifted about above-mentioned at least, thereby make the selectively acting wavelength band and survey wavelength of optical signal band juxtaposition, at this moment, the fiber grating of this measurement point is just to certain reflection or dissipation of having surveyed light signal generating, detector detects the variation that exit end is surveyed light signal strength, thereby detects the variation of described physical quantity.
Description
Affiliated technical field
The present invention relates to a kind of fiber-optic grating sensor, is the sensor of surveying by optical fiber and fiber grating, surveys the method that physical quantity changes, and this physical quantity can be temperature or the like, and this method belongs to field of sensing technologies.
Background technology
We know that optical fiber is the passage of light conducting signal, because its design feature, optical fiber is very responsive to residing environment, as variation of temperature, optical fiber are shunk, and the result causes it that the variation that detects easily takes place, as the decay increase of light signal.When optical fiber is subjected to mechanical stress, pressure variation, electric field or changes of magnetic field, also above-mentioned variation can take place, therefore, many known sensors are with the variation of fiber-optic probe physical quantity.In this sensor of a part, use fiber grating, relatively be typically Bragg grating.Below we are called Bragg grating with fiber grating, but be not that application of the present invention is only only limited to Bragg grating.
Bragg grating is selected reverberator as a kind of wavelength, the wavelength of reflectance spectrum (being the reflection wavelength band) can be subjected to the influence of STRESS VARIATION and produce mobile, by the monitoring of reflection wavelength Tape movement promptly being known the situation of change of physical quantity.Existing Bragg grating proving installation is to utilize wideband light source to be injected into Bragg grating, and the measurement of the reflected light signal wavelength change of light source being carried out according to Bragg grating, but this method needs expensive instrument that reflection wavelength is carried out demodulation to be determined, this device comprises wideband light source and complicated Wavelength demodulation device, make this device Yin Gaoang in practical engineering application cost and be restricted.
Summary of the invention
The objective of the invention is to formulate the sensor of a kind of use fiber grating (as Bragg grating), to avoid above-mentioned defective.
For this reason, the present invention proposes a kind of fiber-optic grating sensor, comprise light source, optical fiber, detector and be placed on the optical fiber be positioned at measurement point be used to monitor the fiber grating that physical quantity changes, it is characterized in that:
The detection light signal of one light source output injects from an end that is called the incident end of optical fiber, and the wavelength of surveying light signal and has the preset wavelength difference with described selectively acting wavelength not in the selectively acting wavelength band of fiber grating,
One when monitored physical quantity variation reaches certain value, be positioned at the preset wavelength difference that the selectively acting wavelength band of the fiber grating of measurement point has drifted about above-mentioned at least, thereby make this selectively acting wavelength band cover the part of described detection wavelength of optical signal band at least, at this moment, the fiber grating of this measurement point is just to certain reflection or dissipation of having surveyed light signal generating, promptly survey the part reflection or the dissipation of light signal, thereby other end exit end at the incident end of optical fiber, then detect the variation of transmitted light, thereby detect the variation of described physical quantity.
The present invention surveys to be monitored a kind of fiber-optic grating sensor that physical quantity changes, it is the variation that has utilized optical signal transmissive, determine the variation of the physical quantity of described measurement point: if variation has taken place near the physical quantity of being monitored a fiber grating, and the variation that takes place has reached the degree that we are concerned about, at this moment the selectively acting wavelength band of the fiber grating preset wavelength difference of having drifted about at least, thereby make this selectively acting wavelength band cover a part of surveying the wavelength of optical signal band at least, at this moment, the fiber grating of this measurement point is just to certain reflection or dissipation of having surveyed light signal generating, promptly survey the part reflection of light signal or dissipate, detector detects the variation of transmitted light, this explanation has stress to exist, thereby may detect the variation of respective physical amount.
In actual engineering, we usually only need obtain the data that a part of physical quantity changes, just can reach our target, in the fire temperature warning system, we press for understanding to the state of temperature below 25 ℃ the time, we only need to set a monitoring, alarming temperature, as 65 ℃, then as the fiber grating on the optical fiber of sensor, measure this fiber grating in the time of 65 ℃ the selectively acting wavelength band and choose a wavelength as the wavelength of surveying light signal, select light source according to this wavelength then, described fiber grating is when normal temperature (as 20 ℃), its selectively acting wavelength band has wavelength difference with the wavelength of the detection light signal of selecting, this sensor is installed in the place of monitoring, as warehouse etc., under normal conditions, environment temperature generally can not reach 65 ℃, so the detection light signal of injection sensor fiber is at less optical fiber and the fiber grating of having passed through of loss, can record intensity at the detector of the exit end of optical fiber through light signal, and as benchmark, have only when the temperature of measurement point near or when reaching 65 ℃, the fiber grating selectively acting wavelength band of this measurement point will drift about and with the wavelength band juxtaposition of surveying light signal, and to surveying suitable reflection or the dissipation of light signal generating, at this moment, can monitor obvious variation on the detector through the intensity of light signal, thereby triggered the fire temperature alert if, reached the purpose of monitoring.
Above-mentioned example, also can realize with the system that wide light source and complicated Wavelength demodulation device are formed, this system data of all fiber gratings under the continuous substantially temperature between can obtaining from normal temperature to the alarm temperature, then the temperature of measurement point near or report to the police when reaching alarm temperature, this system testing has obtained the data that have little significance in a large number as can be seen, and expensive instrument also is higher to maintenance requirement.So in similarity,, obviously be uneconomic with respect to the monitoring system that adopts the inventive method with the monitoring system that wide light source and complicated Wavelength demodulation device are formed.
Under actual engineering specifications, a value of only monitoring physical quantity usually is not enough, so the different a plurality of detection light signals of wavelength can be set, just can monitor a plurality of values of physical quantity, the trend that changes of measurement point physical quantity as can be seen simultaneously is so that better monitoring.
Description of drawings:
Fig. 1 is the reflectance spectrum of a Bragg grating of expression, the spectrum of a detection light signal and both graphs of a relation;
Fig. 2 is the transmitted spectrum of a long period fiber grating of expression, the spectrum of a detection light signal and both graphs of a relation;
Fig. 3 is the structured flowchart of the fiber-optic grating sensor of relevant first embodiment of the present invention of expression;
Fig. 4 is the structured flowchart of the fiber-optic grating sensor of relevant second embodiment of the present invention of expression;
Fig. 5 is the structured flowchart of the fiber-optic grating sensor of relevant the 3rd embodiment of the present invention of expression;
Among the figure: 3,3a, 3b, 3n one light source,
9a, 9b one optical branching device,
5 one fiber gratings
6,6a, 6b, 6n one photo-detector,
7 one optical fiber,
8 one photoswitches,
10a, 10b, 10n one fixed wave filter.
Embodiment
Curve 1 among Fig. 1 has schematically shown the reflectance spectrum of a Bragg grating, λ
1And λ
2Be respectively the lower limit and the upper limit wavelength of this Bragg grating reflection wavelength, all wavelength all are the wavelength that Bragg grating can reflect in these two wavelength, are called the reflection wavelength band here.Curve 2 has schematically shown a spectrum of surveying light signal, λ
3And λ
4Be respectively the lower edge and the upper edge wavelength of this detection light signal, λ
2And λ
3Between distance be exactly that described preset wavelength is poor.
Curve 11 among Fig. 2 has schematically shown the transmitted spectrum of a long period fiber grating, λ
1And λ
2Be respectively the lower limit and the upper limit wavelength of this long period fiber grating coupling attenuation wavelength, long period fiber grating all has decay to all wavelength in these two wavelength, is called the dissipation wavelength band here.Curve 2 has schematically shown a spectrum of surveying light signal, λ
3And λ
4Be respectively the lower edge and the upper edge wavelength of this detection light signal, λ
2And λ
3Between distance be exactly that described preset wavelength is poor.
First embodiment
Fig. 3 is the structured flowchart of the fiber-optic grating sensor of expression first embodiment.The fiber-optic grating sensor of first embodiment by light source 3, photo-detector 6, be positioned at measurement point and be used to monitor fiber grating 5 and the optical fiber 7 that physical quantity changes and constitute.Connect with optical fiber between each parts.
Detection light signal from light source 3 outputs, the wavelength of surveying light signal is not in the selectively acting wavelength band of fiber grating 5, and default wavelength difference arranged with it, survey light signal by optical fiber 7 and fiber grating 5, and detect the intensity of surveying light signals by photo-detector 6, at monitored physical quantity no change or change when not reaching the degree that we are concerned about, the wavelength of surveying light signal is not at the selectively acting wavelength band of the fiber grating 5 that is positioned at measurement point, be that fiber grating 5 is not to surveying light signal reflection or consume, at this moment to detect be zero-decrement substantially light signal to photo-detector 6, and with this intensity as benchmark, when the physical quantity of monitored point changes to the degree of our care, the selectively acting wavelength band that is positioned at the fiber grating 5 of the described measurement point described preset wavelength difference of having drifted about at least, at this moment described selectively acting wavelength band has covered a part of surveying the wavelength of optical signal band at least, this fiber grating 5 is just to suitable reflection or the dissipation of having surveyed light signal generating, at this moment photo-detector 6 detects the intensity of surveying light signal obvious variation, thereby detects the variation of physical quantity.
Second embodiment
Fig. 4 is the structured flowchart of the fiber-optic grating sensor of expression second embodiment.The fiber-optic grating sensor of second embodiment by light source 3a, light source 3b, light source 3n, photo-detector 6, photoswitch 8, be positioned at measurement point and be used to monitor fiber grating 5 and the optical fiber 7 that physical quantity changes and constitute.Connect with optical fiber between each parts.
From light source 3a, light source 3b, the detection light signal of the different wave length of light source 3n output, the wavelength of surveying light signal is not all in the selectively acting wavelength band of fiber grating 5, and different preset wavelength differences arranged with it, photoswitch 8 can select the detection light signal of Different Light by optical fiber 7 and fiber grating 5, arrive photo-detector 6, at this moment to detect be zero-decrement substantially light signal to photo-detector 6, and with this intensity as benchmark, the variation of monitored physical quantity can cause the drift of the selectively acting wavelength band of fiber grating 5, when preset wavelength difference that the selectively acting wavelength band has drifted about different, we can detect the Strength Changes of the different detection light signal of input, so just can detect a plurality of values that physical quantity changes.
The 3rd embodiment
Fig. 5 is the structured flowchart of the fiber-optic grating sensor of expression the 3rd embodiment.The fiber-optic grating sensor of the 3rd embodiment by light source 3a, light source 3b, light source 3n, wave filter 10a, wave filter 10b, wave filter 10n, photo-detector 6a, photo-detector 6b, photo-detector 6n, optical branching device 9a, optical branching device 9b, be positioned at measurement point and be used to monitor fiber grating 5 and the optical fiber 7 that physical quantity changes and constitute.Connect with optical fiber between each parts.
From light source 3a, light source 3b, the detection light signal of the different wave length of light source 3n output, the wavelength of surveying light signal is not all in the selectively acting wavelength band of fiber grating 5, and different preset wavelength differences arranged with it, survey light signal by optical branching device 9a, again by optical fiber 7, fiber grating 5 and optical branching device 9b, enter into different detectors by different wave filters respectively, each wave filter and light source are one to one, and only allow the detection light signal of corresponding wavelength to pass through, other detection filtered optical signal is fallen, and when physical quantity do not changed each intensity of surveying light signal as benchmark, the variation of monitored physical quantity can cause the drift of the selectively acting wavelength band of fiber grating 5, when the selectively acting wavelength band has drifted about described different preset wavelength difference, will cause the variation of different detection light signal strengths, all detection light signals see through optical fiber 7 and optical branching device 9b, enter into different detectors by different wave filters respectively, detector will be at this moment each intensity of surveying light signal and corresponding benchmark strength ratio, we just can detect a plurality of values of physical quantity variation like this.
As seen, the method according to detection of the present invention is simpler than the method for prior art.
Certainly, the present invention is not limited to the embodiment that the front is introduced, and we can replace whole device with another kind of equivalent arrangements, and do not exceed scope of the present invention.
Claims (2)
1. fiber-optic grating sensor, comprise light source, optical fiber, detector and be placed on the optical fiber be positioned at measurement point be used to monitor the fiber grating that physical quantity changes, it is characterized in that:
The detection light signal of one light source output injects from an end that is called the incident end of optical fiber, and the wavelength of surveying light signal and has the preset wavelength difference with described selectively acting wavelength not in the selectively acting wavelength band of fiber grating,
One when monitored physical quantity variation reaches certain value, be positioned at the preset wavelength difference that the selectively acting wavelength band of the fiber grating of measurement point has drifted about above-mentioned at least, thereby make this selectively acting wavelength band cover the part of described detection wavelength of optical signal band at least, at this moment, the fiber grating of this measurement point is just to certain reflection or dissipation of having surveyed light signal generating, promptly survey the part reflection of light signal or dissipate, detector detects the variation that the optical fiber exit end is surveyed light signal strength, thereby detects the variation of described physical quantity.
2. a kind of fiber-optic grating sensor according to claim 1, it is characterized in that: a plurality of light sources inject a plurality of detection light signals from an end that is called the incident end of optical fiber, its wavelength is not all in described reflection wavelength band, and have different preset wavelength differences, thereby can detect a plurality of values that the measurement point physical quantity changes with reflection wavelength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200810100061XA CN101598574A (en) | 2008-06-03 | 2008-06-03 | A kind of fiber-optic grating sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200810100061XA CN101598574A (en) | 2008-06-03 | 2008-06-03 | A kind of fiber-optic grating sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101598574A true CN101598574A (en) | 2009-12-09 |
Family
ID=41420093
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA200810100061XA Pending CN101598574A (en) | 2008-06-03 | 2008-06-03 | A kind of fiber-optic grating sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101598574A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110954143A (en) * | 2018-09-27 | 2020-04-03 | 冲电气工业株式会社 | Optical fiber sensor device and optical fiber sensor system |
-
2008
- 2008-06-03 CN CNA200810100061XA patent/CN101598574A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110954143A (en) * | 2018-09-27 | 2020-04-03 | 冲电气工业株式会社 | Optical fiber sensor device and optical fiber sensor system |
| CN110954143B (en) * | 2018-09-27 | 2022-03-08 | 冲电气工业株式会社 | Optical fiber sensor device and optical fiber sensor system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2010308572C1 (en) | Stimulated brillouin system with multiple FBG's | |
| US7418171B2 (en) | Fibre Bragg grating sensors | |
| US7129470B2 (en) | Optical sensor using a long period grating suitable for dynamic interrogation | |
| US9599460B2 (en) | Hybrid Raman and Brillouin scattering in few-mode fibers | |
| CN103542925B (en) | Quasi-distributed optical vibrating sensing device | |
| EP2795260B1 (en) | Fiber sensing system based on a bragg grating and optical time domain reflectometry | |
| CN101603841A (en) | A kind of fiber-optic grating sensor | |
| CO5730013A1 (en) | SYSTEM FOR MEASUREMENT AND DATA ACQUISITION FOR OPTICAL FIBER SENSORS | |
| KR101474068B1 (en) | The nuclear power plant monitering system for environment using the fiber bragg grating | |
| CN101424631A (en) | Optical fibre grating sensor | |
| CN101424626A (en) | Optical fibre grating sensor | |
| CN101603842A (en) | A kind of fiber-optic grating sensor | |
| CN101598574A (en) | A kind of fiber-optic grating sensor | |
| KR102036260B1 (en) | Submergence detection sensor using optical fiber grating | |
| CN101424621A (en) | Optical fibre grating sensor | |
| CN101598577A (en) | A kind of fiber-optic grating sensor | |
| CN101813496A (en) | Fiber Bragg grating sensor and Raman sensor-fused sensing system | |
| CN101598576A (en) | Survey the method for physical quantity with linear sensor | |
| CN101424632A (en) | Optical fibre grating sensor | |
| CN101424630A (en) | Optical fibre grating sensor | |
| CN101598575A (en) | Survey the method for physical quantity with linear sensor | |
| CN101424625A (en) | Optical fibre grating sensor | |
| Jinachandran et al. | Fibre Bragg grating based acoustic emission measurement system for structural health monitoring applications, Materials, 2021, vol. 14 | |
| CN101424624A (en) | Optical fibre grating sensor | |
| CN101424628A (en) | Optical fibre grating sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| DD01 | Delivery of document by public notice |
Addressee: Xi'an Jinhe Optical Technology Co., Ltd. Document name: Notification of Patent Invention Entering into Substantive Examination Stage |
|
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20091209 |