CN102012281A - Single-ended dual-wavelength high-precision distributed optical fiber temperature sensor - Google Patents
Single-ended dual-wavelength high-precision distributed optical fiber temperature sensor Download PDFInfo
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- CN102012281A CN102012281A CN2010105261476A CN201010526147A CN102012281A CN 102012281 A CN102012281 A CN 102012281A CN 2010105261476 A CN2010105261476 A CN 2010105261476A CN 201010526147 A CN201010526147 A CN 201010526147A CN 102012281 A CN102012281 A CN 102012281A
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Abstract
The invention discloses a single-ended dual-wavelength high-precision distributed optical fiber temperature sensor, and belongs to the technical field of optical fiber sensing. In the single-ended dual-wavelength high-precision distributed optical fiber temperature sensor, two light sources with different wavelengths are connected to a pulse driver to ensure that the required precision of spatial resolution is achieved while the required pulse light energy is provided by utilizing the pulse widths of the two light sources. Therefore, the problem that the spatial resolution cannot meet the required precision in the prior art is solved, and the single-ended dual-wavelength high-precision distributed optical fiber temperature sensor is suitable for places with high precision requirement, such as petrochemical pipelines, electric high-voltage switches and the like.
Description
Technical field
The present invention relates to the light field of sensing technologies, specifically a kind of design proposal of single light source both-end input detecting distributed optical fiber temperature sensor.
Background technology
Distributed optical fiber temperature sensor occurred many commercially produced products so far, yet the index that is reached can not meet the demands still under many occasions since coming out.Especially the measuring accuracy of distributed optical fiber temperature sensor and defence area spatial resolution, measuring accuracy and the defence area the highest index level of spatial resolution correspond to 1 ℃ and 0.1m at present, and still are in development mostly.
The ultimate principle of Fibre Optical Sensor is: the light that is sent by light source enters modulator zone through optical fiber, under the effect of measurand, variation has taken place in optical properties such as light intensity, wavelength, frequency, phase place, polarization state, make the signal that it becomes modulated, send into photo-detector and electric signal process unit through optical fiber again, finally obtain the information of object to be measured.
Usually, for being less than, the spatial resolution technology that makes the distributed optical fiber Raman temperature sensor product equals 1m, light source need produce the pulsed light smaller or equal to 10ns, and single wavelength light pulse can not be too big, otherwise non-linear phenomena will take place in Raman diffused light, thereby cause scattered light signal very weak, so there is great difficulty in the way by super burst pulse (less than 10ns) light source directly is provided when photodetection.
In recent years; the spatial resolution technology of distributed optical fiber Raman temperature sensor product has reached 1m; but can't satisfy the application requirements that the spatial resolution of decimeter grade is realized in fields such as pipelines and petrochemical pipelines, power high voltage switch and the protection of power cable heat; though can adopt the probe thermometric of optical fiber winding; but the randomness of heat affected zone can't be estimated.The temperature measurement accuracy of distributed optical fiber Raman temperature sensor product has been less than 1 ℃ on the other hand, but does not also satisfy the needs of 0.1 ℃ of petrochemical industry reaction.
Summary of the invention
In order to solve problems of the prior art, the invention provides a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor, its technical scheme that adopts is: pulse driver connects two light sources that wavelength is different, the light that two light sources send is combined into a branch of through a wave multiplexer, enter sensor fibre from optical branching device; Optical branching device connects two wave filters, is used for afterwards being separated into anti-Stokes (Anti-stokes) light that carries temperature signal to what sensor fibre produced and as Stokes (Stokes) light with reference to signal to Raman diffused light.
The present invention adopts two light sources that wavelength is different, by the pulse driver synchro control, send the different pulsed light of two beam pulse width, utilize the first group pulse light, compare with the back scattering light signal that second light-pulse generator produces, at this moment, by the difference of the pulse width of synchronously driven each light-pulse generator of pulse driver and each pulse width be the principal element of decision spatial resolution.Difference in pulse width is more little, and corresponding spatial resolution is high more, and contrast is obtained respectively organizes Raman diffused light, thereby can measure physical quantities.According to this measure physical quantities, thereby measure detection signal in can be between very short fiber region, thus, can significantly improve spatial resolution.
Adopt the backscatter sounding method, by the synchronous narrow light pulse that produces two different pulse width t1 and t2 of pulse driver, i.e. probe pulse launched.The stand out of two probe pulse launched has been determined the spatial resolution of distributed optical fiber temperature sensing system, photo-detector is the contribution summation of the back scattering luminous energy of the one section optical fiber corresponding with light impulse length in the luminous energy that detects sometime, therefore just determined a spatial resolution by the light impulse length difference, the narrow light pulse of such two different pulse width t1 and t2 can be selected wideer light pulse for use, and the spatial resolution of system is only determined by light impulse length poor (t1-t2), can improve laser pulse width and obtain better signal to noise ratio (S/N ratio) under same spatial resolution, the reduction that single peak-power of laser pulse is required can prevent fiber nonlinear effect again effectively.。
Single-ended dual wavelength high precision distributed optical fiber temperature sensor of the present invention, utilize the light source of the different light impulse lengths of two different wave lengths to produce spontaneous Raman scattering effect and optical time domain reflection principle synchronously, utilize the wavelength of wave multiplexer to divide the actinic light function, dexterously back scattering anti-Stokes (Anti-stokes) light, Stokes (Stokes) light are merged, strengthened the Raman scattering light intensity of the temperature information that carries in the optical fiber; Improved the signal to noise ratio (S/N ratio) of sensing system, made the measuring accuracy of system temperature improve, spatial resolution is higher.
Neither with light pulse through the incident end of Optical Fiber Transmission to wave multiplexer, enter sensor fibre through optical branching device, the rear orientation light that produces in sensor fibre enters two wave filters via optical branching device again, the anti-Stokes Raman scattering that obtains carrying temperature signal after the separation is closed the glistening light of waves and as the stokes scattering light with reference to signal, has just been finished the extraction work of light signal since then.
Further, the anti-Stokes Raman scattering that obtains carrying temperature signal after the separation is closed the glistening light of waves and as the stokes scattering light with reference to signal, insert high-speed, high precision distributed temperature measuring processing host again and carry out Photoelectric Signal Processing, analytical calculation, just finally obtain the temperature field information of corresponding point.
Described wave multiplexer is that wavelength division multiplexer etc. has the components and parts that close wave energy; Described optical branching device is the components and parts that fiber coupler or optical fiber circulator etc. have the beam split function
Further, described pulse driver also comprises synchronous signal output end, with the synchronizing signal delivery outlet output of synchronizing signal via crust of the device.Described synchronizing signal is and the light pulse of the laser instrument output electric impulse signal of output synchronously, it can notify high-speed, high precision distributed temperature measuring processing host begin A the D signals collecting.
The invention has the advantages that: by connecting two wavelength and pulse width light source inequality on the pulse driver, utilize the difference in pulse width of two-beam signal more little, the relation that the spatial resolution of system is low more, the difference in pulse width of two-beam signal is set as required, make system under the nondecreasing prerequisite of incident optical signal energy, obtain enough little difference in pulse width, thereby obtain the spatial resolution of needs; Improved the measuring accuracy of system greatly.This invention efficiently solves traditional fiber districution temperature sensor and " improves spatial resolution-reduction signal to noise ratio (S/N ratio), improve signal to noise ratio (S/N ratio)-reduction spatial resolution or increase Measuring Time " this contradiction, has improved temperature measurement accuracy.Can be applicable to the profile fiber temperature-sensing system of very-long-range, high spatial resolution.
Description of drawings
Fig. 1 is a general structure synoptic diagram of the present invention;
Embodiment
Embodiment 1: pulse driver 3 connects light source 1 and light source 2, light source 1 is connected wavelength division multiplexer 4 simultaneously with light source 2, wavelength division multiplexer 4 connects a fiber coupler 5, one end of fiber coupler 5 connects sensor fibre 6, and two output terminals of fiber coupler 5 connect wavelength division multiplexer 7 and wavelength division multiplexer 8; Two wavelength division multiplexers are connected on the high-speed, high precision distributed temperature measuring processing host 9.
In the present embodiment, light source 1 sends the pulsed optical signals that pulse width is 10nm, light source 2 sends the pulsed optical signals that pulse width is 9nm, two pulsed light width are 1nm, two ways of optical signals enters an Optical Fiber Transmission through wavelength division multiplexer 4, after enter into sensor fibre 6 through fiber coupler 5, the back can take place to Raman scattering in pulsed optical signals when transmitting in sensor fibre, the back is separated into the anti-Stokes Raman scattering of carrying temperature signal through wavelength division multiplexer 7 and wavelength division multiplexer 8 with Raman diffused light to Raman diffused light and closes the glistening light of waves and as the stokes scattering light with reference to signal, just finished the extraction work of light signal since then.
The anti-Stokes Raman scattering that obtains carrying temperature signal after the separation is closed the glistening light of waves and as the stokes scattering light with reference to signal, insert high-speed, high precision distributed temperature measuring processing host 9 again and carry out Photoelectric Signal Processing, analytical calculation, just finally obtain the temperature field information of corresponding point.
Described pulse driver 3 also comprises synchronous signal output end, with the synchronizing signal delivery outlet output of synchronizing signal via crust of the device.Described synchronizing signal is and the light pulse of the laser instrument output electric impulse signal of output synchronously, it can notify high-speed, high precision distributed temperature measuring processing host 9 beginning A the D signals collecting.
In the present embodiment, the pulsed light width of two pulsed optical signals is 1nm, and the spatial resolution of corresponding system is about 0.1m, and temperature measurement accuracy belongs to the most accurate measuring system in the present distributed optical fiber temperature sensor for 0.1 ℃.
Here description of the invention and application is illustrative, is not to want with scope restriction of the present invention in the above-described embodiments.Here the distortion of disclosed embodiment and change are possible, and the various parts of the replacement of embodiment and equivalence are known for those those of ordinary skill in the art.Those skilled in the art are noted that under the situation that does not break away from spirit of the present invention or essential characteristic, and the present invention can be with other forms, structure, layout, ratio, and realize with other elements, material and parts.Under the situation that does not break away from the scope of the invention and spirit, can carry out other distortion and change here to disclosed embodiment.
Claims (6)
1. single-ended dual wavelength high precision distributed optical fiber temperature sensor is characterized in that: connect two light sources that wavelength is different on the pulse driver, the light that two light sources send is combined into a branch of through a wave multiplexer, enter sensor fibre from optical branching device; Optical branching device connects two wave filters, and the rear orientation light that produces in the sensor fibre passes through wave filter the required anti-Stokes light that carries temperature signal is afterwards imported processing host with separating as the stokes light with reference to signal.
2. a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor according to claim 1, it is characterized in that: the optical signal pulses width that described two light sources send can be controlled by pulse driver.
3. a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor according to claim 1 is characterized in that: described wave multiplexer comprises that wavelength division multiplexer etc. has the components and parts that close wave energy.
4. a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor according to claim 1, it is characterized in that: described shunt refers to that fiber coupler or optical fiber circulator etc. have the components and parts of beam split function.
5. a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor according to claim 1 is characterized in that: described wave filter refers to the components and parts that wavelength division multiplexer or filter plate etc. can filtered light signal.
6. a kind of single-ended dual wavelength high precision distributed optical fiber temperature sensor according to claim 1, it is characterized in that: described pulse driver also comprises synchronous signal output end, with the synchronizing signal delivery outlet output of synchronizing signal via crust of the device.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106525279A (en) * | 2016-11-11 | 2017-03-22 | 武汉理工光科股份有限公司 | Multi-wavelength-light-source-based method for increasing working distance of distributed spontaneous Raman scattering temperature sensing system |
| CN111896137A (en) * | 2020-06-29 | 2020-11-06 | 太原理工大学 | Centimeter-level spatial resolution distributed optical fiber Raman sensing device and method |
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2010
- 2010-10-29 CN CN2010105261476A patent/CN102012281A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106525279A (en) * | 2016-11-11 | 2017-03-22 | 武汉理工光科股份有限公司 | Multi-wavelength-light-source-based method for increasing working distance of distributed spontaneous Raman scattering temperature sensing system |
| CN111896137A (en) * | 2020-06-29 | 2020-11-06 | 太原理工大学 | Centimeter-level spatial resolution distributed optical fiber Raman sensing device and method |
| CN111896137B (en) * | 2020-06-29 | 2022-02-18 | 太原理工大学 | Centimeter-level spatial resolution distributed optical fiber Raman sensing device and method |
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Application publication date: 20110413 |