CN101458100A - Demodulation system of FBG sensor and demodulation method thereof - Google Patents
Demodulation system of FBG sensor and demodulation method thereof Download PDFInfo
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- CN101458100A CN101458100A CNA2009103001607A CN200910300160A CN101458100A CN 101458100 A CN101458100 A CN 101458100A CN A2009103001607 A CNA2009103001607 A CN A2009103001607A CN 200910300160 A CN200910300160 A CN 200910300160A CN 101458100 A CN101458100 A CN 101458100A
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Abstract
The invention provides a demodulating system of an FBG sensor and a demodulating method thereof; wherein, the system has low requirement on uniformity of FBG central wave length and low cost and is easy to be realized. The demodulating system of the FGB sensor is characterized in that a light-pulse generator, a circulator or a coupler and a coupler are connected in sequence, and then one route is connected with a sideband filter and a photoelectric pickoff in sequence, the other route is connected with the photoelectric pickoff, and finally the two routes are connected with a divider and a sensor signal response processing module in sequence. The invention has the advantage that the central wave length of the FBG sensor in the invention only needs to be within the bandwidth range of a filter, thus having low production requirement; in addition, the demodulating system has simple structure, low cost, good stability, and high resolution; as the system is not restricted by light sources, ordinary broadband light resources or laser light resources are applicable, thus reducing the cost. With the combination of the time-domain reflection technology and the edge filtering method, the invention can realize multiplex of the FBG sensor, wave length demodulation and space orientation with low cost, therefore, the system is easy to be realized.
Description
Technical field
The present invention relates to field of sensing technologies, particularly relate to the demodulating system and the demodulation method thereof of a kind of FBG (fibber bragg gratting) sensor.
Background technology
Along with the FBG sensor moves towards practical application, FBG Wavelength demodulation technology becomes key point.With the sensor-based system of optical fiber optical grating constitution, serve as modulation number because the sensing amount mainly is a small wavelength variations with wavelength, so the accurate wavelength or the pick-up unit of wavelength variations should be arranged in the sensor-based system.The measuring accuracy of wavelengt demodulator has directly limited the accuracy of detection of total system.
For a FBG Wavelength demodulation device must consider following some: the output of the signal of the stability of detuner wavelength resolution, the long-term non-stop run of detuner, the price of detuner, detuner is readable.Application number is 02115542.9 to disclose a kind of temp monitoring and alarming system with identity optical fibre raster, but this system is because the grid of sharing the same light of will demanding perfection, the bad realization of actual fabrication, and this method can not realize the space orientation of the numerical measuring and the FBG of FBG wavelength in addition; Application number is 200610124955.3 to disclose a kind of high speed optic fiber grating wavelength demodulating system, the fiber grating of this system requirements different wave length, cost height.
Present most of optical fiber grating regulating system all respectively has own relative merits, is difficult to problems such as multiplexing, the Wavelength demodulation of solution sensor comprehensively and space orientation.
Summary of the invention
Technical matters to be solved by this invention provides a kind of demodulating system and demodulation method thereof of FBG sensor, this system is not high to FBG centre wavelength coherence request, can realize multiplexing, the Wavelength demodulation and the space orientation of FBG sensor, and low being easy to of cost realized.
The technical scheme that technical solution problem of the present invention is adopted is: the demodulating system of FBG sensor, this system is connected with light source, circulator or coupling mechanism, coupling mechanism according to this, one tunnel fillet band filter and photodetector according to this then, another road connects photodetector, and last two-way is connected with the transducing signal response processing module with divider more according to this.
The demodulation method of FBG sensor, this method may further comprise the steps: after 1) common wideband light source process external modulation or LASER Light Source become light pulse through internal modulation, be sent to the FBG sensor by circulator or coupling mechanism; 2) FBG sensor Time Domain Reflectometry reflected signal uses coupling mechanism to be divided into 2 the tunnel to handle respectively, and one the tunnel directly passes through photodetector, and photodetector is passed through again through behind sideband filter in another road; 3) with divider this two paths of signals is divided by at last, the otdr signal after being divided by draws the place of wavelength variations generation and the size after the wavelength variations after the transducing signal response processing module is handled.
The invention has the beneficial effects as follows: the centre wavelength of FBG sensor of the present invention only needs in the sideband filter bandwidth range, and is less demanding to making; Demodulating system is simple, has characteristics such as cost is low, good stability, resolution height; Light source is unrestricted, can adopt common wideband light source or LASER Light Source, has further reduced cost.Multiplexing, Wavelength demodulation and space orientation that the present invention combines and can realize the FBG sensor by Time Domain Reflectometry technology and edge filter method, low being easy to of cost realized.
Description of drawings
Fig. 1 is a system chart of the present invention.
Fig. 2 is the system chart of another kind of structure of the present invention.
Embodiment
As depicted in figs. 1 and 2, the present invention adopts common wideband light source or LASER Light Source, after common wideband light source process external modulation or LASER Light Source become light pulse through internal modulation, be sent to the FBG sensor by circulator or coupling mechanism, the centre wavelength of FBG sensor changes with variations such as ambient temperature or stress, can realize sensing.The otdr signal that the FBG sensor reflects uses coupling mechanism to be divided into 2 the tunnel and handles respectively, and one the tunnel directly passes through photodetector, and photodetector is passed through again through behind the sideband filter in another road, with divider this two paths of signals is divided by at last.Otdr signal after being divided by is after the transducing signal response processing module is handled, by analyzing the Time Domain Reflectometry waveform, utilize OTDR (Optical Time Domain Reflectometer optical time domain reflectometer) principle can draw the place that wavelength variations takes place, analyze the result of divider, draw the size after the wavelength variations.
The centre wavelength scope of the bandwidth of above-mentioned sideband filter and FBG sensor is consistent; The bandwidth of above-mentioned light source has covered the wavelength variation range of FBG sensor greater than the bandwidth of FBG sensor.
The present invention has realized the multiplexing of sensor, if use the lower FBG sensor of reflectivity, and a sense line a plurality of FBG sensors of can connecting, distance sensing increases, and most transducing signal can not be reflected, and signal intensity is stronger; If use the higher FBG sensor of reflectivity, the number of sensors of series connection will be subjected to certain restriction.
Claims (5)
- The demodulating system of [claim 1] FBG sensor, it is characterized in that: this system is connected with light-pulse generator, circulator or coupling mechanism, coupling mechanism according to this, one tunnel fillet band filter and photodetector according to this then, another road connects photodetector, and last two-way is connected with the transducing signal response processing module with divider more according to this.
- The demodulating system of [claim 2] FBG sensor as claimed in claim 1 is characterized in that: the centre wavelength scope of the bandwidth of described sideband filter and FBG is consistent.
- The demodulation method of [claim 3] FBG sensor is characterized in that: this method may further comprise the steps: after 1) common wideband light source process external modulation or LASER Light Source become light pulse through internal modulation, be sent to the FBG sensor by circulator or coupling mechanism; 2) FBG sensor otdr signal uses coupling mechanism to be divided into 2 the tunnel to handle respectively, and one the tunnel directly passes through photodetector, and photodetector is passed through again through behind sideband filter in another road; 3) with divider this two paths of signals is divided by at last, the otdr signal after being divided by draws the place of wavelength variations generation and the size after the wavelength variations after the transducing signal response processing module is handled.
- The demodulation method of [claim 4] FBG sensor as claimed in claim 3 is characterized in that: the bandwidth of described light source has covered the wavelength variation range of FBG sensor greater than the bandwidth of FBG sensor.
- The demodulation method of [claim 5] FBG sensor as claimed in claim 3 is characterized in that: the centre wavelength scope of the bandwidth of described sideband filter and FBG is consistent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CNA2009103001607A CN101458100A (en) | 2009-01-13 | 2009-01-13 | Demodulation system of FBG sensor and demodulation method thereof |
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| CNA2009103001607A CN101458100A (en) | 2009-01-13 | 2009-01-13 | Demodulation system of FBG sensor and demodulation method thereof |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101813496A (en) * | 2010-04-15 | 2010-08-25 | 电子科技大学 | Fiber Bragg grating sensor and Raman sensor-fused sensing system |
| CN104154935A (en) * | 2014-08-14 | 2014-11-19 | 哈尔滨理工大学 | Method for improving sensitivity of FBG demodulation system based on sideband filtering |
| CN104864911A (en) * | 2015-05-29 | 2015-08-26 | 北京航空航天大学 | High-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement |
| CN105352446A (en) * | 2015-11-30 | 2016-02-24 | 上海交通大学 | Sub-nano strain level multi-point multiplexing fiber grating quasi static strain sensor system |
| CN111521206A (en) * | 2020-07-03 | 2020-08-11 | 武汉智慧地铁科技有限公司 | Wavelength demodulation method for fiber grating edge superposition filtering |
| CN113624267A (en) * | 2021-07-21 | 2021-11-09 | 浙江理工大学 | Fiber grating center wavelength demodulation system and demodulation instrument based on edge filtering |
-
2009
- 2009-01-13 CN CNA2009103001607A patent/CN101458100A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101813496A (en) * | 2010-04-15 | 2010-08-25 | 电子科技大学 | Fiber Bragg grating sensor and Raman sensor-fused sensing system |
| CN104154935A (en) * | 2014-08-14 | 2014-11-19 | 哈尔滨理工大学 | Method for improving sensitivity of FBG demodulation system based on sideband filtering |
| CN104154935B (en) * | 2014-08-14 | 2016-08-24 | 哈尔滨理工大学 | Raising method based on linear filter FBG demodulating system sensitivity |
| CN104864911A (en) * | 2015-05-29 | 2015-08-26 | 北京航空航天大学 | High-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement |
| CN105352446A (en) * | 2015-11-30 | 2016-02-24 | 上海交通大学 | Sub-nano strain level multi-point multiplexing fiber grating quasi static strain sensor system |
| CN105352446B (en) * | 2015-11-30 | 2018-01-30 | 上海交通大学 | Levels of strain multipoint multiplexing fiber grating quasistatic strain sensing system is received in Asia |
| CN111521206A (en) * | 2020-07-03 | 2020-08-11 | 武汉智慧地铁科技有限公司 | Wavelength demodulation method for fiber grating edge superposition filtering |
| CN111521206B (en) * | 2020-07-03 | 2020-10-13 | 武汉智慧地铁科技有限公司 | Wavelength demodulation method for fiber grating edge superposition filtering |
| CN113624267A (en) * | 2021-07-21 | 2021-11-09 | 浙江理工大学 | Fiber grating center wavelength demodulation system and demodulation instrument based on edge filtering |
| CN113624267B (en) * | 2021-07-21 | 2024-05-03 | 浙江理工大学 | Fiber bragg grating center wavelength demodulation system and demodulator based on edge filtering |
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Open date: 20090617 |