CN100507455C - Intensity modulation type optical fiber sensor multiplexing method - Google Patents
Intensity modulation type optical fiber sensor multiplexing method Download PDFInfo
- Publication number
- CN100507455C CN100507455C CNB200710177834XA CN200710177834A CN100507455C CN 100507455 C CN100507455 C CN 100507455C CN B200710177834X A CNB200710177834X A CN B200710177834XA CN 200710177834 A CN200710177834 A CN 200710177834A CN 100507455 C CN100507455 C CN 100507455C
- Authority
- CN
- China
- Prior art keywords
- sensor
- wavelength
- light
- fiber
- spectrum
- 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.)
- Expired - Fee Related
Links
Images
Abstract
The invention relates to a repeated use method for an adjustable strength optical fiber sensor. A board band light source (1) is changed into wave length scanning light through an adjustable Fabry-Perot filter (3). One branch of the board band light source enters into a sensor array after being divided through a coupler 4, and the reflective light is detected through detectors(7 and 8); while the other branch is detected through a detector 6 as reference light. Each sensor component comprises two optical fiber gratings (12 and 14) with different wave lengths, and an adjustable strength optical fiber sensor (13). The two optical fiber gratings are respectively connected with the two ends of the strength sensor in series. The method comprises the steps as follows: eliminating the influence of uneven light source through a reference channel (6), measuring the change of the light strength of the strength sensor (13), and achieving the repeated use of the strength sensor through the optical fiber gratings with different wave lengths. Besides, the invention can achieve the large-scale repeated use and array of the adjustable strength optical fiber sensor by further increasing the quantity of the coupling.
Description
Technical field
The invention belongs to the fiber optic sensor technology field, particularly a kind of multiplexing method of intensity modulation optical fiber sensor and the technology that realizes this method.
Background technology
The multiplex technique of intensity modulation optical fiber sensor commonly used mainly is based on the back-scattering light of optical fiber or the light time territory Distributed Detection method of forward scattering optical loss time domain detection technique at present.The distributed typical case representative of time domain is based on the sensor multiplexing monitoring of optical time domain reflectometer (OTDR) and based on the multiplexing method of Brillouin light time-domain reflectomer (BOTDR).Sensor based on optical time domain reflectometer (OTDR) has one section blind area in use all the time, and the pad value of measuring from the optical fiber two ends has difference, and the resolution that can reach is not high enough.And very little based on the sensor of Brillouin light time-domain reflectomer (BOTDR) owing to Brillouin shift, and its live width is very narrow, and this just requires laser instrument to have high frequency stability and extremely narrow (about kHz) adjustable live width, and optical filter is also had high requirement.Therefore this system is making and is using not only complexity but also costliness.
Summary of the invention
The objective of the invention is to overcome deficiency of the prior art, propose the multiplexing method of a kind of intensity modulation optical fiber sensor, the technology that realizes this method is provided simultaneously.This method is low to the light source performance requirement, and antijamming capability is strong, and there is not the blind area of similar OTDR system in the Measurement Resolution height.
Technical scheme of the present invention
(1) select for use wavelength coverage to cover the light source of fiber grating reflectance spectrum; Incident light enters tunable F-P wave filter through isolator; Incident light enters first coupling mechanism, and is divided into two-beam through behind the tunable F-P filter filtering, and wherein a branch of received and deliver on the signal acquiring processing system by photodetector, obtains the spectral shape of original light source; Another Shu Guang is divided into the aplanatic light of two bundles after through second coupling mechanism again, and this two-beam also enters two sensor groups passages through the 3rd coupling mechanism and the 4th coupling mechanism respectively;
(2) fiber grating will be positioned at the fiber grating central wavelength lambda
11λ
12λ
N1λ
N2The light reflected back coupling mechanism at place, reflected light are sent on the signal acquiring processing system after being received by photodetector, obtain signal spectrum;
(3) signal spectrum and original spectrum are divided by, and get rid of the inhomogeneous influence to measuring of spectral profile, obtain spectrum in wavelength X
11λ
12λ
N1λ
N2The loss at place, and by measuring wavelength X
11With λ
12, λ
21With λ
N2λ
N1With λ
N2Between loss difference, promptly obtain the loss of each corresponding Fibre Optical Sensor position.
In each sensor groups, two fiber grating and intensity modulation optical fiber sensors that wavelength is adjacent are arranged, the fiber grating in each sensor groups is connected on the two ends of intensity modulation type sensor respectively.The light that enters the sensor groups passage obtains discrete spectrum through the reflection back, and wavelength is respectively λ
11λ
12λ
N1λ
N2Wherein two optic fiber grating wavelengths in same sensor groups are inequality, wherein in first sensor groups, and the light λ of a wavelength
11Directly reflected by fiber grating, and another wavelength X
12Just reflected after then having passed through sensor by fiber grating, so wavelength X
12Carried the intensity modulated information of sensor, and wavelength X
11Then be as a contrast wavelength.Because light source light spectrum is not uniformly, therefore need be with the wavelength X that collects
11λ
12Signal spectrum and original light source light spectrum are divided by, and get rid of the uneven influence of light source light spectrum, and wavelength X
11λ
12Between loss difference be exactly the loss of its respective sensor position.Same, wavelength is λ
21λ
22λ
N1λ
N2Also can handle, obtain the loss of respective sensor by above method.And, do not have interference between the different sensor groups, relevant because the loss of sensor only changes with the light intensity contrast of the fiber grating reflected back at its two ends, and irrelevant with the state of other sensor groups.So this method can realize the independent distribution formula of intensity modulation type sensor and measure, and factors such as temperature to external world, humidity have very strong anti-interference.
The equipment of realizing such scheme is: wideband light source links to each other with the input end of tunable F-P wave filter through behind the isolator, the output terminal of tunable F-P wave filter is connected with an end light signal of first fiber coupler, and another output terminal of first fiber coupler links to each other with second fiber coupler with photodetector 6 respectively.The output terminal of photodetector 6 is connected on the signal acquiring processing system.Two output terminals of second fiber coupler link to each other with the input end of the 3rd fiber coupler with the 4th fiber coupler respectively.Another road input end of the 3rd fiber coupler and the 4th fiber coupler is connected on the signal acquiring processing system through photodetector 7,8.The 3rd fiber coupler and the 4th fiber coupler a plurality of sensor groups of connecting respectively.Comprise in each sensor groups two wavelength near but fiber grating inequality, and intensity modulation type sensor, wherein fiber grating is connected on the two ends of intensity modulation type sensor respectively.
Beneficial effect of the present invention
The present invention is mainly used in the multiplexing and multiplexed of a plurality of intensity modulation optical fiber sensors.Because optic fiber grating wavelength is stable, utilize the measuring method of the loss contrast between this two different wave lengths, when realization is multiplexing, can reach very high precision and resolution.And temperature to external world, factors such as humidity have very strong anti-interference.
Description of drawings
Fig. 1 is an one-piece construction synoptic diagram of the present invention, wherein: 1-wideband light source, 2-isolator 3-tunable F-P wave filter 4-the first fiber coupler 5-the second fiber coupler 6-photodetector 7,8-photodetector, 9-signal acquiring processing system, 10-the three fiber coupler, 11-the four fiber coupler 12,14-fiber grating, 13-intensity modulation type sensor;
The spectrum synoptic diagram that Fig. 2 sends for light source;
Fig. 3 is for being example with one group of sensor, original light source scan light spectrogram;
Fig. 4 is for being example with one group of sensor, the spectrum when the intensity modulation type sensor is lossless (normalization spectrum);
Fig. 5 is for being example with one group of sensor, the spectrum when the intensity modulation type sensor is lossy.
Embodiment
As shown in Figure 1, be example with one group of sensor groups, wideband light source 1 (as the ASE light source) enters tunable F-P wave filter 3 through isolator 2.Through behind the filter filtering, the light of output is connected to the input end of first fiber coupler 4, and the output terminal of first fiber coupler 4 connects the photodetector 6 and second fiber coupler 5 respectively.The output terminal of photodetector 6 is connected on the signal acquiring processing system 9.Two output terminals of second fiber coupler 5 link to each other with the input end of the 3rd fiber coupler 10 and the 4th fiber coupler 11 respectively.The 3rd fiber coupler 10 and the 4th fiber coupler 11 another road input ends are connected on the signal acquiring processing system 9 through photodetector 7,8.The output terminal of the 3rd fiber coupler 10 and the 4th fiber coupler 11 is connected with sensor groups.Comprise in the sensor groups two centre wavelengths near but fiber grating 12 and 14 inequality, and intensity modulation type sensor 13, fiber grating is connected on the two ends of intensity modulation type sensor respectively.The sensor group is placed in the environment to be measured, and other parts can be placed on outside monitoring center.
Select for use wavelength coverage to cover the ASE light source 1 of fiber grating reflectance spectrum, former spectral shape as shown in Figure 2; Behind wave filter 3, become length scanning formula spectrum, as shown in Figure 3.After this light signal enters sensor groups, reflected by the fiber grating of different centre wavelengths.The reflected signal that sensor groups reflects comprises two wavelength optical signals, and the signal that wherein is placed on the optical grating reflection before the sensing head is as the reference signal, and the signal that is placed on the optical grating reflection behind the sensing head has then carried heat transfer agent.These two wavelength optical signals are divided by normalization with the original signal that photodetector 6 receives after receiving through detector.If sensing head is lossless, then the variable power at two wavelength places should be identical after the normalization, as shown in Figure 4; If the sensing head place is lossy, then the variable power of two wavelength has a difference after the normalization, and this difference is exactly the loss that the sensing head place produces, as shown in Figure 5.Just can monitor by the variation of observing the sensing head loss the variation of its residing environmental physics amount.
Because two differences that stop position is placed in the sensor groups, the loss information that causes one of the light signal of reflected back not carry sensing head, another has then reflected the loss situation at sensing head place.Therefore can be with the signal of loss information that do not carry sensing head as the reference signal, and another is as transducing signal.In addition, because the instability of original light source need be carried out normalization with two signals, the loss difference between two reflectance spectrums after the normalization is only the real loss that has reflected that the sensing head place produces.
As seen from Figure 1, adopt this structure, can not have the problem that interferes with each other between the sensor groups, and other factors are to the influence of grating to external world, as temperature, humidity is vibrated or the like, and very strong anti-interference is all arranged.So the method can realize the extensive multiplexing and distributed measurement of intensity modulation type sensor, and has the sensing accuracy height, advantage such as it is low to make complexity, and the signal demodulation is simple.
Claims (2)
1. the multiplexing method of an intensity modulation optical fiber sensor is characterized in that the method includes the steps of:
(1) select for use wavelength coverage to cover the light source of fiber grating reflectance spectrum; Incident light enters tunable F-P wave filter through isolator; Incident light enters first coupling mechanism (4), and is divided into two-beam through behind the tunable F-P filter filtering, and wherein a branch of received and deliver on the signal acquiring processing system by photodetector, obtains the spectral shape of original light source; Another Shu Guang is divided into the aplanatic light of two bundles after through second coupling mechanism (5) again, and this two-beam also enters two sensor groups passages through the 3rd coupling mechanism (10) and the 4th coupling mechanism (11) respectively;
(2) fiber grating will be positioned at the fiber grating central wavelength lambda
11λ
12λ
N1λ
N2The light reflected back coupling mechanism at place, reflected light are sent on the signal acquiring processing system after being received by photodetector, obtain signal spectrum;
(3) signal spectrum and original spectrum are divided by, and obtain spectrum in wavelength X
11λ
12λ
N1λ
N2The loss at place, and by measuring wavelength X
11With λ
12, λ
21With λ
22..., λ
N1With λ
N2Between loss difference, promptly obtain the loss of each corresponding Fibre Optical Sensor position;
In each sensor groups, two fiber grating and intensity modulation optical fiber sensors that wavelength is adjacent are arranged, the fiber grating in each sensor groups is connected on the two ends of intensity modulation type sensor respectively; The light that enters the sensor groups passage obtains discrete spectrum through the reflection back, and wavelength is respectively λ
11λ
12λ
N1λ
N2Wherein two optic fiber grating wavelengths in same sensor groups are inequality, wherein in first sensor groups, and the light λ of a wavelength
11Directly reflected by fiber grating, and another wavelength X
12Just reflected after then having passed through sensor by fiber grating, so wavelength X
12Carried the intensity modulated information of sensor, and wavelength X
11Then be as a contrast wavelength; Because light source light spectrum is not uniformly, therefore need be with the wavelength X that collects
11λ
12Signal spectrum and original light source light spectrum are divided by, and get rid of the uneven influence of light source light spectrum, and wavelength X
11λ
12Between loss difference be exactly the loss of its respective sensor position; Same, wavelength is λ
21λ
22λ
N1λ
N2Also can handle, obtain the loss of respective sensor by above method; And, do not have interference between the different sensor groups, relevant because the loss of sensor only changes with the light intensity contrast of the fiber grating reflected back at its two ends, and irrelevant with the state of other sensor groups; So this method can realize the independent distribution formula of intensity modulation type sensor and measure, and temperature to external world, humidity factor have very strong anti-interference.
2. adopt the employed equipment of claim 1 method, it is characterized in that: wideband light source in this equipment (1) connects the input port of optoisolator (2), the output of optoisolator (2) connects the input port of first fiber coupler (4) by tunable method amber wave filter (3) filtering, and one tunnel output of first fiber coupler (4) is connected on the signal acquiring processing system (9) through photodetector (6); Another road output of first fiber coupler (4) then is connected to the input port of second fiber coupler (5); Two output terminals of second fiber coupler (5) link to each other with the input end of the 3rd fiber coupler (10) with the 4th fiber coupler (11) respectively; Another road input end of the 3rd fiber coupler (10) and the 4th fiber coupler (11) is connected on the signal acquiring processing system (9) through photodetector (7,8); The 3rd fiber coupler (10) and the 4th fiber coupler (11) a plurality of sensor groups of connecting respectively; Comprise two fiber gratings that wavelength is inequality in each sensor groups, and an intensity modulation type sensor, wherein two fiber gratings are connected on the two ends of intensity sensor respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200710177834XA CN100507455C (en) | 2007-11-21 | 2007-11-21 | Intensity modulation type optical fiber sensor multiplexing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200710177834XA CN100507455C (en) | 2007-11-21 | 2007-11-21 | Intensity modulation type optical fiber sensor multiplexing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101169334A CN101169334A (en) | 2008-04-30 |
| CN100507455C true CN100507455C (en) | 2009-07-01 |
Family
ID=39390030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200710177834XA Expired - Fee Related CN100507455C (en) | 2007-11-21 | 2007-11-21 | Intensity modulation type optical fiber sensor multiplexing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100507455C (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102104421B (en) * | 2009-12-16 | 2015-03-25 | 华为技术有限公司 | Branched optical fiber failure detection method and device for optical network, and optical network |
| CN101915593A (en) * | 2010-07-16 | 2010-12-15 | 山东大学 | Device for demodulating fiber bragg grating reflection wavelength by utilizing ASE light source light spectrum failing edge |
| CN102207458A (en) * | 2011-04-08 | 2011-10-05 | 东北大学 | Signal demodulation method for fiber grating-based near-infrared absorption type concentration sensor |
| CN102506917A (en) * | 2011-12-03 | 2012-06-20 | 太原理工大学 | Optical fiber sensing device for optical fiber chaos laser device and method thereof |
| CN102589588A (en) * | 2012-02-17 | 2012-07-18 | 南京师范大学 | Method for demodulating cavity length of Fabry-Perot cavity by utilizing fiber Bragg gratings |
| CN103557984B (en) * | 2013-11-04 | 2015-10-07 | 贵州大学 | A kind of method for packing of differential pressure pick-up probe and structure |
| CN103557986B (en) * | 2013-11-04 | 2015-08-12 | 贵州大学 | A kind of differential pressure pick-up intensity compensation method and device |
| CN103557985B (en) * | 2013-11-04 | 2015-09-23 | 贵州大学 | A kind of differential pressure method for sensing and sensor thereof |
| CN103776475A (en) * | 2014-01-28 | 2014-05-07 | 浙江大学 | Optical fiber sensor and sensing method based on linear filter and photoelectric detector |
| CN109087476A (en) * | 2018-02-06 | 2018-12-25 | 上海光栅信息技术有限公司 | A kind of fiber grating line-type heat detector demodulation process operation method |
| CN112082581B (en) * | 2020-06-05 | 2022-12-13 | 哈尔滨工业大学 | Quasi-distributed physical quantity measuring method, device and system based on distributed feedback laser array |
-
2007
- 2007-11-21 CN CNB200710177834XA patent/CN100507455C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101169334A (en) | 2008-04-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100507455C (en) | Intensity modulation type optical fiber sensor multiplexing method | |
| CN201476800U (en) | High-speed multi-channel fiber grating sensor demodulating system based on AWG | |
| US7157693B2 (en) | Optical wavelength interrogator | |
| US6680472B1 (en) | Device for measuring of optical wavelengths | |
| CN101881634A (en) | High-speed multi-channel fiber bragg grating (FBG) sensing demodulation system based on AWG (Arrayed Waveguide Grating) and method | |
| JP2001525938A (en) | Distributed detection system | |
| CN102494801B (en) | Distributed optical delay optical fiber temperature sensor | |
| CN101000267A (en) | Parallel distribution optical fibre raster temp. sensing method and its system | |
| GB2332272A (en) | Wavelength detection with fibre Bragg grating sensors | |
| CN102661755A (en) | Fiber Bragg grating-based extensible distributed sensing system | |
| CN103245369A (en) | Novel fiber bragg grating demodulation method and system thereof based on multi-longitudinal mode F-P laser device | |
| CN104215605A (en) | Method for fast dynamic-calibration of fiber bragg grating (FBG) demodulation system | |
| CN111397851A (en) | OFDR multi-path optical fiber sensing system and method based on optical frequency comb technology | |
| JP2004233070A (en) | Fbg sensing system | |
| CN100406938C (en) | Coherent multiplexing method for optical fiber Bragg raster sensor and apparatus thereof | |
| Nureev et al. | Distributed Raman sensor system with point spots for downhole telemetry | |
| WO2020245893A1 (en) | Determination device and determination method | |
| CN205642638U (en) | Simple and easy low -cost real -time measuring device of wavelength | |
| AU2020103490A4 (en) | A multiplexing optical fiber interferometer and its nesting construction method | |
| JP3317281B2 (en) | Optical path length measuring device for arrayed waveguide diffraction grating | |
| US6417926B1 (en) | Wavelength measuring system | |
| JP2022544522A (en) | Method and system for interrogating a fiber Bragg grating type fiber optic sensor using a tunable optical bandpass filter | |
| CN100393015C (en) | Multi-wavelength light source generator and the optical amplifier testing method therewith | |
| CN220982299U (en) | Environment state monitoring system | |
| CN211425533U (en) | City piping lane multi-parameter optical fiber distributed measuring device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090701 Termination date: 20131121 |