CN112964387B - Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer - Google Patents
Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer Download PDFInfo
- Publication number
- CN112964387B CN112964387B CN202110229892.2A CN202110229892A CN112964387B CN 112964387 B CN112964387 B CN 112964387B CN 202110229892 A CN202110229892 A CN 202110229892A CN 112964387 B CN112964387 B CN 112964387B
- Authority
- CN
- China
- Prior art keywords
- temperature
- stokes
- optical fiber
- measured
- optical
- 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.)
- Active
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 89
- 238000001069 Raman spectroscopy Methods 0.000 title claims abstract description 45
- 230000003287 optical effect Effects 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000000835 fiber Substances 0.000 claims abstract description 35
- 238000005259 measurement Methods 0.000 claims abstract description 11
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 238000011088 calibration curve Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000253 optical time-domain reflectometry Methods 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K15/00—Testing or calibrating of thermometers
- G01K15/002—Calibrated temperature sources, temperature standards therefor
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
本发明公开了一种拉曼光时域反射计中光纤沿线温度的解调方法，通过获取不同参考温度下参考光纤的反斯托克斯与斯托克斯光强度比，根据不同参考温度下参考光纤的反斯托克斯与斯托克斯光强度比拟合得到不同参考温度下参考光纤的反斯托克斯与斯托克斯光强度比曲线，确定转换参考温度的比例系数，利用特定参考温度及其拉曼强度比，将待测段强度比及比例系数代入特定解调公式，结合标定公式计算待测光纤的温度，所获得的待测光纤温度具有较高的准确性；其中利用参考光纤的数据计算，提高了测量结果的准确性与稳定性，且参考光纤处不需要恒温，降低系统成本，提高系统的适用范围。
The invention discloses a method for demodulating the temperature along an optical fiber in a Raman optical time domain reflectometer. The anti-Stokes and Stokes light intensity ratio of the reference fiber is fitted to obtain the anti-Stokes and Stokes light intensity ratio curves of the reference fiber at different reference temperatures, and the proportional coefficient for converting the reference temperature is determined by using For a specific reference temperature and its Raman intensity ratio, the intensity ratio and proportional coefficient of the segment to be measured are substituted into the specific demodulation formula, and the temperature of the optical fiber to be measured is calculated in combination with the calibration formula, and the obtained temperature of the optical fiber to be measured has high accuracy; Using the data calculation of the reference fiber improves the accuracy and stability of the measurement results, and does not require constant temperature at the reference fiber, reduces the cost of the system, and increases the scope of application of the system.
Description
Technical Field
The invention relates to the technical field of optical fiber sensing, in particular to a method for demodulating the temperature along an optical fiber in a Raman optical time domain reflectometer.
Background
The distributed optical fiber sensing technology is a sensing technology that has appeared along with the development of optical fiber and optical communication technologies, and the ROTDR, i.e., Raman optical time domain reflectometer, is a technology for temperature measurement using a combination of two technologies, Raman (Raman) scattering effect and Optical Time Domain Reflectometer (OTDR).
Raman scattering, also known as the raman effect, refers to the phenomenon in which incident light interacts with a propagation medium to cause a change in the frequency of the light. Raman scattering is used for distributed fiber sensing, and the principle is that after laser is injected into an optical fiber, the laser generates inelastic scattering with molecules and atoms of a fiber medium, and causes the incident photons to emit or absorb high-frequency phonons related to the vibration of the molecules and atoms of the medium, wherein the former is called Stokes (Stokes) photons, and the latter is called anti-Stokes (anti. In the ROTDR, the anti-stokes light is more sensitive to temperature change than the stokes light, generally speaking, the temperature and raman scattering intensity ratio, that is, the ratio of the anti-stokes light divided by the stokes light intensity is in a linear relationship, a fixed temperature T0 is used as a reference to obtain a temperature calibration curve, then the intensities of the anti-stokes light and the stokes light signals at different temperatures are measured to obtain the raman intensity ratio at the temperature, and finally the actual temperature is calculated through the temperature calibration curve.
However, in the application of the actual environment, since attenuation and loss occur when the laser light propagates in the optical fiber, the temperature calculation result obtained by directly demodulating the acquired raman intensity ratio by using the temperature calibration curve is not accurate. Therefore, a temperature calibration curve is usually used first, and then an empirical formula is used to obtain the actual temperature. However, the empirical formula is usually only applicable to a certain reference temperature, and once the temperature at the reference fiber changes, the result obtained by using the empirical formula and the temperature calibration curve will have errors. In order to solve the problems, the conventional scheme is to place the reference optical fiber into the constant temperature box and ensure the accuracy of the demodulation result by keeping the temperature of the reference optical fiber constant. And the measured signals under the same reference and temperature to be measured are also changed by the problems of laser, acquisition card, optical fiber winding and the like.
Disclosure of Invention
Aiming at the problems, the invention provides a method for demodulating the temperature along the optical fiber in a Raman optical time domain reflectometer, which is characterized in that a standard reference temperature and a reference optical fiber are set in the Raman optical time domain reflectometer, a reference temperature conversion coefficient is obtained by utilizing a reference section temperature-Raman intensity ratio curve and the position temperature, and the temperature distribution along the optical fiber is demodulated by combining a temperature calibration curve, so that the problem of deviation of a demodulation temperature result under different reference temperatures caused by light attenuation, unstable devices and the like is solved, and the accuracy and the stability of an optical time domain reflectometer system are improved.
In order to achieve the purpose of the invention, the invention provides a method for demodulating the temperature along the optical fiber in the Raman optical time domain reflectometer, which comprises the following steps:
s10, setting a certain section of the optical fibers as a reference optical fiber, installing a thermometer on the section, and setting the rest optical fibers as sections to be tested;
s20, placing the reference optical fiber in a thermostat with a specific reference temperature, placing the optical fiber to be measured in another thermostat, and adjusting the temperature of the thermostat of the section to be measured to obtain the anti-Stokes and Stokes light intensity ratios of the two sections at different temperatures to be measured;
s30, adjusting the temperature of the thermostat at the reference fiber to obtain the anti-Stokes and Stokes light intensity ratio of the reference fiber at different reference temperatures;
s50, fitting according to the anti-Stokes and Stokes light intensity ratios of the reference optical fibers at different reference temperatures to obtain anti-Stokes and Stokes light intensity ratio curves of the reference optical fibers at different reference temperatures;
s70, determining a proportionality coefficient of the conversion reference temperature according to the thermometer result, the optical signal intensity ratio and the anti-Stokes-to-Stokes light intensity ratio at the reference optical fiber;
and S80, substituting the intensity ratio and the proportionality coefficient of the section to be measured into a specific demodulation formula by using the specific reference temperature and the Raman intensity ratio thereof, and calculating the temperature of the optical fiber to be measured by combining a calibration formula.
In one embodiment, after step S30, the method further includes:
and S40, obtaining a calibration formula at the specific reference temperature by using the calibration formula and the known temperature to be measured.
Specifically, the original formula includes:
the calibration formula comprises:
T＝1.0917T1-10.792，
wherein, T0Indicating a specific reference temperature, T indicating the true temperature of the section to be measured, T1The temperature of the section to be measured which is calculated by using a demodulation formula below and is not calibrated in the last step is represented, h represents a Planck constant, c represents an optical speed, k represents a Boltzmann constant, v represents a Raman frequency shift, R (T) represents the anti-Stokes-to-Stokes light intensity ratio of the optical fiber of the section to be measured, and R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
In one embodiment, the specific demodulation formula includes:
wherein, T0Denotes a specific reference temperature, h denotes a Planckian constant, c denotes an optical speed, k denotes a Boltzmann constant, v denotes a Raman frequency shift, R (T)1) Representing the anti-Stokes to Stokes light intensity ratio, T, of the section of fibre to be measured1Representing the temperature of the section to be measured calculated by using a demodulation formula, which needs to be further calibrated to obtain the final real temperature of the section to be measured, x representing the proportionality coefficient of the conversion reference temperature, R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
In one embodiment, after step S50, the method further includes:
s60, performing field measurement to obtain the anti-stokes optical signal intensity ratio and the temperature at the reference fiber.
The demodulation method for the temperature along the optical fiber in the Raman optical time domain reflectometer has the following technical effects:
1. and the accuracy and stability of the measurement result are improved by using the data calculation of the reference optical fiber.
2. The reference optical fiber does not need to be constant in temperature, so that the system cost is reduced, and the application range of the system is widened.
Drawings
FIG. 1 is a flowchart of a method for demodulating the temperature of an optical fiber along a line in a Raman optical time domain reflectometer according to an embodiment;
FIG. 2 is a schematic diagram of a ROTDR structure of an embodiment;
FIG. 3 is a flowchart of a method for demodulating the temperature of an optical fiber along the line in a Raman optical time domain reflectometer according to another embodiment;
FIG. 4 is a graphical comparison of temperature results obtained using a calibration equation for one embodiment at a particular temperature;
FIG. 5 is a diagram illustrating the calibration relationship of the temperature demodulation result at a reference temperature of 16 ℃ according to an embodiment;
FIG. 6 is a graphical representation of the results of directly using a particular temperature calibration equation at different reference temperatures for one embodiment;
FIG. 7 is a diagram illustrating a calculation result of a segment under test using the method provided in the present application according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application 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 present application and are not intended to limit the present application.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
Referring to fig. 1, fig. 1 is a flowchart of a demodulation method of temperature along a fiber in a raman optical time domain reflectometer according to an embodiment, including the following steps:
s10, a certain section of the optical fibers is set as a reference optical fiber, a thermometer is installed in the section, and the remaining optical fibers are set as a section to be measured.
S20, placing the reference optical fiber in a thermostat with a specific reference temperature, placing the optical fiber to be measured in another thermostat, and adjusting the temperature of the thermostat of the section to be measured to obtain the anti-Stokes and Stokes light intensity ratio of the two sections at different temperatures to be measured.
The steps can realize calibration, and a calibration curve is made according to the anti-Stokes and Stokes light intensity ratios of the two sections at different temperatures to be measured for correcting results in subsequent measurement.
And S30, adjusting the temperature of the thermostat at the reference fiber to obtain the anti-Stokes and Stokes light intensity ratio of the reference fiber at different reference temperatures.
And S50, fitting according to the anti-Stokes and Stokes light intensity ratios of the reference optical fibers at different reference temperatures to obtain anti-Stokes and Stokes light intensity ratio curves of the reference optical fibers at different reference temperatures.
And S70, determining a proportionality coefficient of the conversion reference temperature according to the thermometer result, the optical signal intensity ratio and the anti-Stokes-to-Stokes light intensity ratio at the reference optical fiber.
Specifically, the anti-stokes and stokes light intensity ratios of the reference fiber at different reference temperatures of the reference segment (reference fiber) are obtained in step S30, and a temperature-light intensity ratio curve is obtained after fitting. The light intensity ratio of the corresponding temperature in step S30 is divided by the actually measured light intensity ratio, so that the proportionality coefficient of the conversion reference temperature can be obtained.
And S80, substituting the intensity ratio and the proportionality coefficient of the section to be measured into a specific demodulation formula by using the specific reference temperature and the Raman intensity ratio thereof, and calculating the temperature of the optical fiber to be measured by combining a calibration formula.
This step sets the specific reference temperature T0And the anti-Stokes to Stokes light intensity ratio R (T) of the reference section fiber0) And the calculated proportionality coefficient x and the Stokes light and anti-Stokes light intensity ratio R (T) of the segment to be measured1) Substituting into a specific demodulation formula to obtain the calculated temperature T1And finally, obtaining the measured temperature T by using a calibration formula.
In this embodiment, the raman optical time domain reflectometer includes a laser, a photodetector, a wavelength division multiplexer, an optical fiber, and a collection card, where the wavelength division multiplexer is configured to separate stokes light and anti-stokes light and transmit the separated stokes light and anti-stokes light to the photodetector in two paths, and the separated stokes light and anti-stokes light are collected by the collection card.
The demodulation method of the temperature along the optical fiber in the Raman optical time domain reflectometer comprises the steps of setting a certain section of the optical fiber as a reference optical fiber, installing a thermometer on the section, setting the rest optical fibers as sections to be detected, placing the reference optical fiber in a constant temperature box with a specific reference temperature, placing the optical fiber to be detected in another constant temperature box, adjusting the temperature of the constant temperature box at the section to be detected to obtain the anti-Stokes and Stokes light intensity ratios of the two sections at different temperatures to be detected, adjusting the temperature of the constant temperature box at the reference optical fiber to obtain the anti-Stokes and Stokes light intensity ratios of the reference optical fiber at different reference temperatures, fitting the anti-Stokes and Stokes light intensity ratios of the reference optical fiber at different reference temperatures to obtain anti-Stokes and Stokes light intensity ratio curves of the reference optical fiber at different reference temperatures, and fitting the anti-Stokes and Stokes light intensity ratios according to the thermometer result, the optical signal intensity ratio and the anti-Stokes and Stokes light intensity ratios at the reference optical fiber, determining a proportional coefficient of the conversion reference temperature, substituting the specific reference temperature and the Raman intensity ratio thereof into a specific demodulation formula, and calculating the temperature of the optical fiber to be measured by combining a calibration formula, wherein the obtained temperature of the optical fiber to be measured has higher accuracy; the data calculation of the reference optical fiber is utilized, the accuracy and the stability of the measuring result are improved, the reference optical fiber does not need to be constant in temperature, the system cost is reduced, and the application range of the system is widened.
In one embodiment, after step S30, the method further includes:
and S40, obtaining a calibration formula at the specific reference temperature by using the calibration formula and the known temperature to be measured.
Specifically, the calculation process mentioned in step S70 is to first obtain the proportionality coefficient x of the conversion reference temperature by using the reference segment real temperature and the anti-stokes and stokes light intensity ratio curves at different reference temperatures calculated in step S40.
Specifically, the original formula includes:
the calibration formula comprises:
T＝1.0917T1-10.792，
wherein, T0Indicating a specific reference temperature, T indicating the true temperature of the section to be measured, T1The temperature of the section to be measured which is calculated by using a demodulation formula and is not calibrated is represented, h represents a Planck constant, c represents an optical speed, k represents a Boltzmann constant, v represents a Raman frequency shift, R (T) represents the anti-Stokes-to-Stokes light intensity ratio of the section to be measured, and R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
In one embodiment, the specific demodulation formula includes:
wherein, T0Denotes a specific reference temperature, h denotes a Planckian constant, c denotes an optical speed, k denotes a Boltzmann constant, v denotes a Raman frequency shift, R (T)1) Representing the anti-Stokes to Stokes light intensity ratio, T, of the segment to be measured1Expressing the temperature of the section to be measured obtained by using a demodulation formula, x expressing the proportionality coefficient of the conversion reference temperature, R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
In one embodiment, after step S50, the method further includes:
s60, performing field measurement to obtain the anti-stokes optical signal intensity ratio and the temperature at the reference fiber.
In an embodiment, the ROTDR structure diagram can be shown in fig. 2, and the ROTDR system is a distributed optical fiber temperature sensing system based on raman effect and optical time domain reflectometry, and includes optoelectronic devices such as a laser, a wavelength division multiplexer, an optical-to-electrical converter, an acquisition card, and an optical fiber. The working principle is that a laser emits pulse laser, a Raman scattering effect occurs when the pulse laser is transmitted in an optical fiber, Stokes light and anti-Stokes light are generated, the Stokes light and the anti-Stokes light are separated by a wavelength division multiplexer, light intensity data are collected through a photoelectric converter and a collection card, the Raman intensity ratio of the Stokes light divided by the anti-Stokes light is calculated, and the temperature along the optical fiber can be obtained through demodulation by combining a temperature calibration curve under a reference temperature T0. The demodulation formula is:
wherein, T0Representing reference temperature, T representing temperature to be measured, h, c, k and v representing Planck constant, light speed, Boltzmann constant and Raman frequency shift, R (T) representing anti-Stokes and Stokes light intensity ratio of optical fiber to be measured, and R (T)0) And represents the anti-stokes and stokes light intensity ratio of the reference section fiber to the reference section fiber.
In practical application, due to attenuation and loss of light propagating in the optical fiber, parameter offset of devices such as a laser and an acquisition card during long-time operation, and the like, the temperature result obtained by directly demodulating the optical signal by using the formula is not accurate. Some processing of the temperature calculation results is usually required using calibration equations, however, the calibration equations are not the same at different reference temperatures. Therefore, once the reference fiber of the calibration formula is determined, the reference fiber must be placed in an incubator, otherwise, the demodulated result has deviation, which limits the use of the raman optical time domain reflectometer and reduces the accuracy of measurement. The demodulation method for the temperature along the optical fiber in the raman optical time domain reflectometer provided in this embodiment is to solve this problem, and reference may be made to fig. 3 for a corresponding working flow.
After the ROTDR system is constructed, the reference fiber and the fiber to be measured are respectively placed in two thermostats, if the temperature of the reference fiber is 16 ℃ and the temperature of the fiber to be measured is 60 ℃, after the collected optical signal is measured, T0 is 16 ℃, and R (T) and R (T0) are substituted into the original formula, and the result is shown in fig. 4(a), wherein about the first 300 meters in the figure are the reference section, and 300 and 500 meters are the sections to be measured, and the following figures are the same. It can be seen that the accuracy of the measurement result is poorer than the actual temperature of 60 ℃. And changing the temperature of the optical fiber to be measured, for example, measuring the temperature once every 5 ℃ or 10 ℃ within the range of 20 ℃ to 900 ℃, obtaining the original formula calculation value and the real temperature value under different temperatures, and obtaining a linear calibration formula, as shown in fig. 5. Wherein T is the true temperature, T1Temperature calculated for direct demodulation: 1.0917T1-10.792。
The temperature of the thermostat of the section to be measured is changed again, for example, 70 ℃, the calculation is carried out by using the original formula and the calibration formula, and the obtained result is shown in fig. 4(b), so that the calibration formula is effective at the reference temperature of 16 ℃.
If the temperature of the reference optical fiber is changed to 25 ℃ and the temperature of the optical fiber to be measured is set to 60 ℃, the temperature of the two thermostats is measured again, the original calibration formula is still used for demodulation to obtain a result as shown in fig. 6, the accuracy of the result is reduced, and the experimental formula obtained under the condition of 16 ℃ is proved to be not suitable for the condition that the reference temperature is 25 ℃.
And changing the temperature of the constant temperature box of the reference section to obtain the anti-Stokes and Stokes light intensity ratio of the reference section at different reference temperatures, for example, measuring every 5 ℃ within the range of 15 ℃ to 40 ℃, and fitting the anti-Stokes and Stokes light intensity ratio curves of the points, as shown in figure 7.
Performing actual measurement, for example, measuring the known reference temperature of 25 deg.C and its anti-Stokes-to-Stokes light intensity ratio, combining the reference segment anti-Stokes-to-Stokes light intensity ratio curve, and calculating the light intensity ratio of the corresponding temperature in the curve at 25 deg.C to the actual temperatureThe ratio of the measured light intensity ratio, i.e. the value of the corresponding point in the curve is divided by the value obtained by measurement, so as to obtain the proportionality coefficient x of the conversion reference temperature which is 1.032:
and then the obtained x and the collected anti-Stokes light intensity ratio R (T) of the segment to be measured to the Stokes light intensity ratio R1) A specific reference temperature T016 ℃ and R (T)0) Calculating the temperature T1The result of the section to be measured can be obtained by combining a calibration formula as shown in FIG. 6, and the accuracy can be seen to be higher.
The demodulation method for the temperature along the optical fiber in the Raman optical time domain reflectometer provided by the embodiment has the following technical effects:
1. and the accuracy and stability of the measurement result are improved by using the data calculation of the reference optical fiber.
2. The reference optical fiber does not need to be constant in temperature, so that the system cost is reduced, and the application range of the system is widened.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
It should be noted that the terms "first \ second \ third" referred to in the embodiments of the present application merely distinguish similar objects, and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may exchange a specific order or sequence when allowed. It should be understood that "first \ second \ third" distinct objects may be interchanged under appropriate circumstances such that the embodiments of the application described herein may be implemented in an order other than those illustrated or described herein.
The terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device that comprises a list of steps or modules is not limited to the listed steps or modules but may alternatively include other steps or modules not listed or inherent to such process, method, product, or device.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (5)
1. A demodulation method for the temperature along the optical fiber in a Raman optical time domain reflectometer is characterized by comprising the following steps:
s10, setting a certain section of the optical fibers as a reference optical fiber, installing a thermometer on the section, and setting the rest optical fibers as sections to be tested;
s20, placing the reference optical fiber in a thermostat with a specific reference temperature, placing the optical fiber to be measured in another thermostat, and adjusting the temperature of the thermostat of the section to be measured to obtain the anti-Stokes and Stokes light intensity ratios of the two sections at different temperatures to be measured;
s30, adjusting the temperature of the thermostat at the reference fiber to obtain the anti-Stokes and Stokes light intensity ratio of the reference fiber at different reference temperatures;
s50, fitting according to the anti-Stokes and Stokes light intensity ratios of the reference optical fibers at different reference temperatures to obtain anti-Stokes and Stokes light intensity ratio curves of the reference optical fibers at different reference temperatures;
s70, determining a proportionality coefficient of the conversion reference temperature according to the thermometer result, the optical signal intensity ratio and the anti-Stokes-to-Stokes light intensity ratio at the reference optical fiber;
s80, substituting the strength ratio and the proportionality coefficient of the section to be measured into a specific demodulation formula by using the specific reference temperature and the Raman strength ratio thereof, and calculating the temperature of the optical fiber to be measured by combining a calibration formula;
the calibration formula comprises:
T＝1.0917T1-10.792，
wherein T represents the real temperature of the section to be measured, T1The temperature of the section to be measured calculated by using a demodulation formula is shown.
2. The method for demodulating the temperature of the optical fiber along the optical fiber in the raman optical time domain reflectometer according to claim 1, further comprising, after the step S30:
and S40, obtaining a calibration formula at the specific reference temperature by using the known temperature to be measured.
3. The method for demodulating the temperature of the optical fiber along the optical fiber in the Raman optical time domain reflectometer as recited in claim 2, wherein the original formula comprises:
wherein, T0Representing a specific reference temperature, h representing a Planck constant, c representing an optical speed, k representing a Boltzmann constant, v representing a Raman frequency shift, R (T) representing an anti-Stokes to Stokes light intensity ratio of the section of the optical fiber to be measured, and R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
4. The method of claim 1, wherein the specific demodulation formula comprises:
wherein, T0Denotes a specific reference temperature, h denotes a Planckian constant, c denotes an optical speed, k denotes a Boltzmann constant, v denotes a Raman frequency shift, R (T)1) Representing anti-stokes and stokes of optical fiber segment to be detectedIntensity ratio of light, T1Representing the temperature of the section to be measured calculated using a demodulation formula, x representing the proportionality coefficient of the conversion reference temperature, R (T)0) Representing the anti-stokes to stokes light intensity ratio of the reference segment fiber.
5. The method for demodulating the temperature of the optical fiber along the optical fiber in the Raman optical time domain reflectometer according to any one of claims 1 to 4, further comprising, after step S50:
s60, performing field measurement to obtain the anti-stokes optical signal intensity ratio and the temperature at the reference fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110229892.2A CN112964387B (en) | 2021-03-02 | 2021-03-02 | Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110229892.2A CN112964387B (en) | 2021-03-02 | 2021-03-02 | Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112964387A CN112964387A (en) | 2021-06-15 |
| CN112964387B true CN112964387B (en) | 2022-03-15 |
Family
ID=76276362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110229892.2A Active CN112964387B (en) | 2021-03-02 | 2021-03-02 | Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112964387B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113654683B (en) * | 2021-08-16 | 2023-12-05 | 许昌许继软件技术有限公司 | A calibration method and device for a distributed optical fiber temperature measurement system |
| CN114485981B (en) * | 2022-01-27 | 2025-01-17 | 宁波杭州湾新材料研究院 | A temperature measurement method and temperature measurement device based on diamond first-order Raman spectroscopy |
| CN114942087B (en) * | 2022-04-29 | 2024-06-25 | 合肥师范学院 | Raman-Stokes light intensity dynamic self-calibration distributed temperature detection system and method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279062A (en) * | 2011-07-19 | 2011-12-14 | 国电南京自动化股份有限公司 | Temperature calibration and demodulation method for distributed optical fiber sensing temperature measurement system |
| CN104535223A (en) * | 2014-12-16 | 2015-04-22 | 武汉理工光科股份有限公司 | Temperature curve self-correcting algorithm and system for distributed optical fiber temperature sensing system |
| CN109060191A (en) * | 2018-08-20 | 2018-12-21 | 北京中彤节能技术有限公司 | A kind of optical fiber temperature measurement system parameter calibration method, device and parameter system |
| CN109900382A (en) * | 2019-04-17 | 2019-06-18 | 广州市晟安测控科技有限公司 | Fiber temperature signal demodulation method, device and fiber optic temperature (FBG) demodulator |
| CN111006788A (en) * | 2019-11-22 | 2020-04-14 | 太原理工大学 | High-precision optical fiber Raman temperature detection method based on anti-Stokes optical self-demodulation |
| CN112033572A (en) * | 2020-09-02 | 2020-12-04 | 南京大学 | A Method for Compensating Bending Loss and Stokes Light and Anti-Stokes Light Attenuation in Optical Time Domain Reflectometer |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2350587A2 (en) * | 2008-09-27 | 2011-08-03 | Sensortran, Inc. | Auto-correcting or self-calibrating dts temperature sensing sytems and methods |
-
2021
- 2021-03-02 CN CN202110229892.2A patent/CN112964387B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279062A (en) * | 2011-07-19 | 2011-12-14 | 国电南京自动化股份有限公司 | Temperature calibration and demodulation method for distributed optical fiber sensing temperature measurement system |
| CN104535223A (en) * | 2014-12-16 | 2015-04-22 | 武汉理工光科股份有限公司 | Temperature curve self-correcting algorithm and system for distributed optical fiber temperature sensing system |
| CN109060191A (en) * | 2018-08-20 | 2018-12-21 | 北京中彤节能技术有限公司 | A kind of optical fiber temperature measurement system parameter calibration method, device and parameter system |
| CN109900382A (en) * | 2019-04-17 | 2019-06-18 | 广州市晟安测控科技有限公司 | Fiber temperature signal demodulation method, device and fiber optic temperature (FBG) demodulator |
| CN111006788A (en) * | 2019-11-22 | 2020-04-14 | 太原理工大学 | High-precision optical fiber Raman temperature detection method based on anti-Stokes optical self-demodulation |
| CN112033572A (en) * | 2020-09-02 | 2020-12-04 | 南京大学 | A Method for Compensating Bending Loss and Stokes Light and Anti-Stokes Light Attenuation in Optical Time Domain Reflectometer |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112964387A (en) | 2021-06-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112964387B (en) | Demodulation method for temperature along optical fiber in Raman optical time domain reflectometer | |
| EP2587238B1 (en) | Optical fibre temperature distribution measurement apparatus | |
| CN108458814B (en) | Self-calibration detection device and temperature demodulation method for optical fiber Raman temperature sensing system | |
| WO2020034558A1 (en) | High-precision temperature demodulation method oriented toward distributed fiber raman sensor | |
| US8734011B2 (en) | Distributed optical fiber temperature sensor based on optical fiber delay | |
| CN109029769A (en) | High-precision temperature demodulation method based on distributed fiber Raman sensing technology | |
| CN109029770B (en) | Distributed optical fiber Raman temperature and strain demodulation method based on loop demodulation | |
| CN104792436B (en) | A kind of distributed optical fiber temperature measuring method | |
| CN102967389A (en) | Distributed optical fiber temperature measuring device for real-time calibration and calibration method | |
| CN103017934A (en) | Self-correction method capable of eliminating wavelength dispersion of distributed Raman temperature measurement system | |
| CN107843357A (en) | Distributed fiber optic temperature and strain detecting method based on Raman scattering | |
| CN103364112A (en) | Parameter calibration and automatic correction method for distributed optical fiber temperature measurement system | |
| CN109580033A (en) | A kind of concrete dam distributed optical fiber temperature measurement data error compensation method | |
| CN101256098A (en) | Method for measuring temperature of distributed optical fiber temperature transducer system | |
| JP2008249515A (en) | Temperature distribution measuring system and temperature distribution measuring method | |
| CN210981350U (en) | Distributed optical fiber humidity and temperature simultaneous detection device | |
| CN103353359B (en) | Distributed temperature-sensitive optical fiber one-point calibration method | |
| CN113654683B (en) | A calibration method and device for a distributed optical fiber temperature measurement system | |
| CN110887527B (en) | Device and method for simultaneously detecting humidity and temperature of distributed optical fibers | |
| CN202631153U (en) | Single-port distributed optic fiber temperature sensor with automatic compensation function | |
| JP7468638B2 (en) | Brillouin optical sensing device and optical sensing method | |
| CN201251668Y (en) | Reuse and demodulation long period optical fiber grating array device | |
| CN104568228B (en) | Calibration method when attenuation coefficients of DTS are different | |
| Huang et al. | A Quasi-Distributed Fiber-Optic Temperature Sensor With a Resolution of 0.07$^{\circ} $ C Based on Fresnel Reflection | |
| Gunday et al. | Analysis of effects of Young modulus variations on Brillouin power and Brillouin frequency shift changes in optical fibers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |