CN120403919B - Multi-point grating optical cable temperature calibration device and calibration method - Google Patents

Abstract

Translated fromChinese

本发明公开一种多点光栅光缆温度定标装置及定标方法，包括第一光缆盘，用于缠绕放置待定标的多点光栅光缆；第二光缆盘，用于接收从第一光缆盘释放且穿过恒温箱的多点光栅光缆，释放后的多点光栅光缆缠绕设置在第二光缆盘上；恒温箱，至少在相对的两侧开设有通孔，使得多点光栅光缆能够从一个通孔穿入箱体，从另一个通孔穿出箱体；光栅解调仪，连接多点光栅光缆，用于实时采集多点光栅光缆中所有光栅的反射光谱或中心波长随时间的变化数据；计算机，计算获得所有的多点光栅光缆的光栅的温度灵敏度和热时间常数。因此，本发明能够一次性完成光缆中每个光栅的温度灵敏度和热时间常数的定标，提供了更全面光栅温度响应特性参数。

The present invention discloses a multi-point grating optical cable temperature calibration device and calibration method, comprising a first optical cable reel for winding and placing a multi-point grating optical cable to be calibrated; a second optical cable reel for receiving the multi-point grating optical cable released from the first optical cable reel and passing through a constant temperature box, and the released multi-point grating optical cable being wound and arranged on the second optical cable reel; a constant temperature box having through holes on at least two opposite sides, allowing the multi-point grating optical cable to pass through one through hole into the box and pass through the other through hole out of the box; a grating demodulator connected to the multi-point grating optical cable for real-time acquisition of reflection spectrum or central wavelength variation data over time of all gratings in the multi-point grating optical cable; and a computer for calculating and obtaining the temperature sensitivity and thermal time constant of all gratings in the multi-point grating optical cable. Therefore, the present invention can complete the calibration of the temperature sensitivity and thermal time constant of each grating in the optical cable at one time, providing more comprehensive grating temperature response characteristic parameters.

Description

Multi-point grating optical cable temperature calibration device and calibration method

Technical Field

The invention relates to a multi-point grating optical cable temperature calibration device and a calibration method, and relates to the technical field of optical fiber sensing.

Background

Optical cables comprising a plurality of fiber bragg gratings (Fiber Bragg Grating, FBG) have wide application in the field of temperature monitoring. To ensure accurate temperature measurements, it is necessary to temperature-sensitively scale each FBG in the fiber optic cable, i.e. determine the relationship of FBG center wavelength as a function of temperature (temperature sensitivity). Furthermore, when measuring rapidly changing temperatures, the structure and materials of the fiber optic cable can affect the speed at which the temperature is transferred to the FBG in the fiber, thereby affecting the response time of the FBG. Characterization of such thermodynamic response characteristics typically uses a thermal time constant. In some applications (such as real-time monitoring of temperature transients), accurate knowledge and compensation of thermal time constants is critical to improving measurement accuracy.

Existing FBG temperature sensitivity calibration is typically performed in the laboratory using a thermostatic device (such as an incubator or a water bath). The optical cable to be calibrated is placed in a constant temperature environment, the environment temperature is changed, the stable value of the FBG center wavelength after the FBG center wavelength reaches the thermal balance is recorded, and then linear fitting is performed to obtain the temperature sensitivity. However, for a cable containing a large number of FBGs and having a long length, it is very difficult to put the whole into a thermostatic device for calibration. If segmented calibration is used, the optical cable needs to be coiled and then placed in a small incubator, which is not only inefficient, but also the stress generated by coiling may affect the accuracy of the calibration result.

For measurement of thermal time constants, it is often necessary to place the FBG rapidly in a temperature step environment, record the change curve of its center wavelength over time, and then fit according to an exponential response model. Such temperature step response measurements and thermal time constants are obtained independently for each FBG in a long-distance fiber optic cable, also faced with inefficiency and complex operation. Furthermore, coiling the fiber optic cable for thermal time constant measurements, the fiber optic cable structure of the coiled portion may differ from the heat transfer characteristics at the time of straightened deployment, affecting the accuracy of the measurement results.

Accordingly, the prior art lacks an apparatus and method capable of efficiently and accurately simultaneously calibrating the temperature sensitivity and thermal time constant of each FBG for a long-distance optical cable including a plurality of FBGs.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, in view of the above problems, an object of the present invention is to provide a multi-point grating optical cable temperature calibration device and calibration method, so as to solve the problems of low temperature sensitivity and thermal time constant calibration efficiency, complex operation and possible inaccuracy of the result in the prior art for a long-distance optical cable including a plurality of FBGs, and to achieve accurate calibration of the temperature sensitivity and thermal dynamic response characteristics of each FBG in the multi-point grating optical cable.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

in a first aspect, the invention provides a multi-point grating optical cable temperature calibration device, which comprises a first optical cable reel, a second optical cable reel, an incubator, a grating demodulator, a multi-point grating optical cable and a computer, wherein:

the first optical cable reel is used for winding and placing a multi-point grating optical cable to be calibrated;

the second optical cable reel is used for receiving the multi-point grating optical cable released from the first optical cable reel and passing through the constant temperature box, and the released multi-point grating optical cable is wound on the second optical cable reel;

the thermostat is provided with through holes at least at two opposite sides, so that the multi-point grating optical cable can penetrate into the case from one through hole and penetrate out of the case from the other through hole;

The grating demodulator is connected with the multi-point grating optical cable and is used for collecting the change data of the reflection spectrums or the center wavelengths of all gratings in the multi-point grating optical cable along with time in real time;

the computer is used for acquiring the data acquired by the grating demodulator and carrying out fitting processing on the acquired data to obtain the temperature sensitivity and the thermal time constant of the gratings of all the multi-point grating optical cable.

In some possible embodiments, the incubator has an accurate temperature control capability, and can stabilize the temperature inside the incubator at a plurality of preset target temperature points, wherein a plurality of incubators are arranged, and a plurality of incubators are arranged in series, so that different temperatures can be respectively set to realize a more complex temperature profile or faster temperature change.

In some possible implementations, the grating demodulator is fixed on the side wall of the first optical cable tray, rotates synchronously with the first optical cable tray, the head end of the multi-point grating optical cable extends to the side wall through a hole on the roller in the first optical cable tray to be connected with the grating demodulator, and the grating demodulator sends the collected data to the computer in a wired or wireless mode.

In some possible embodiments, the through hole is further sealed by a flexible sealing material, so that heat dissipation is reduced.

In some possible embodiments, the first and second reels each use motorized reels or manual reels in combination with length metering devices to achieve precise movement and grating positioning of the multi-point grating cable.

In a second aspect, the present invention also provides a calibration method of a multi-point grating optical cable temperature calibration device, including:

All devices of the multi-point grating optical cable temperature calibration device are installed and fixed according to requirements;

Setting the temperature of the incubator to be a first target temperature T₁, waiting for the temperature in the incubator to be stable, and acquiring the change data of the reflection spectrum or the center wavelength of the grating positioned in the incubator along with time in real time by the grating demodulator; setting the temperature of the incubator to be the next target temperature T₂, reversely rotating the optical cable disc to release the multi-point grating optical cable from the second optical cable disc and pass through the incubator after waiting for stabilization, and so on, setting a plurality of target temperature points T_N, and repeatedly measuring for each target temperature to obtain time-dependent change data of reflection spectrums or center wavelengths of all gratings at a plurality of target temperatures;

Performing single-point single-temperature wavelength-time curve fitting based on the collected time-dependent change data of the reflection spectrum or the central wavelength of each grating at a plurality of target temperatures to obtain fitting coefficients [ b (T₁),b(T₂),……,b(T_N) ] and [ c (T₁),c(T₂),……,c(T_N) ];

for each grating, linear fitting is carried out by taking [ T₁,T₂,……,T_N ] as an independent variable and a fitting coefficient [ c (T₁),c(T₂),……,c(T_N) ] as an dependent variable to obtain the temperature sensitivity of the grating;

for each grating, the thermal time constant τ of that grating is calculated based on the fitting coefficient [ b (T₁),b(T₂),……,b(T_N) ] and the measured temperature point [ T₁,T₂,……,T_N ].

In some possible embodiments, all devices of the multi-point grating optical cable temperature calibration device are installed and fixed, including:

The method comprises the steps that a multi-point grating optical cable winding disc to be calibrated is placed on a first optical cable disc, the head end of the multi-point grating optical cable extends to the side wall through a hole in a roller in the first optical cable disc, a grating demodulator is fixed on the side wall of the first optical cable disc, the head end of the multi-point grating optical cable is connected with the grating demodulator, and the tail end of the multi-point grating optical cable is released from the first optical cable disc and penetrates through an incubator to be connected to a second optical cable disc.

In some possible embodiments, single-point single-temperature wavelength-time curve fitting is performed based on collected time-dependent variation data of reflection spectra or center wavelengths at a plurality of target temperatures of each grating, so as to obtain fitting coefficients, which are specifically:

Wherein lambda_B (T, T) represents the central wavelength of the grating at constant temperature T and time T, a (T), b (T) and c (T) are fitting coefficients at constant temperature T, and fitting coefficients of each grating at target temperature [ a (T₁),a(T₂),……,a(T_N)]、[b(T₁),b(T₂),……,b(T_N) ] and [ c (T₁),c(T₂),……,c(T_N) ] can be obtained through fitting.

In some possible embodiments, for each grating, the temperature sensitivity of the grating is obtained by linear fitting with [ T₁,T₂,……,T_N ] as an independent variable and a fitting coefficient [ c (T₁),c(T₂),……,c(T_N) ] as an dependent variable, and the specific formula is:

;

where S is the temperature sensitivity of the grating and K is a constant.

In some possible embodiments, for each grating, the thermal time constant τ of the grating is calculated based on the fitting coefficient [ b (T₁),b(T₂),……,b(T_N) ] and the measured temperature point [ T₁,T₂,……,T_N ], with the specific formula:

;

where N is the number of measured temperature points and T_i is the measured temperature point.

The invention adopts the technical proposal and has the following characteristics:

1. Meanwhile, the temperature sensitivity and the thermal time constant are calibrated, the calibration of the temperature sensitivity and the thermal time constant of each FBG in the optical cable can be completed at one time, and more comprehensive FBG temperature response characteristic parameters are provided.

2. The invention can efficiently scale the long-distance optical cable containing a plurality of FBGs in batches by adopting a double-optical cable reel cable guiding mode, thereby greatly saving time and manpower.

3. The invention can calibrate in the controlled incubator environment, avoid the interference of complex factors of the field environment, and the straightened optical cable state is closer to the actual deployment condition (compared with coiling), and the obtained sensitivity and time constant are more accurate.

4. The invention can accurately measure the thermal time constant influenced by the optical cable structure, is beneficial to data compensation in dynamic temperature measurement application and improves measurement accuracy.

5. The whole calibration process can realize automatic control, including rotation of the optical cable reel, temperature setting of the incubator, data acquisition and data processing.

In summary, the invention has wide application range and can be widely applied to the temperature characteristic calibration of various long-distance optical cables containing FBG.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Like parts are designated with like reference numerals throughout the drawings. In the drawings:

FIG. 1 is a schematic diagram of a temperature scaling device for a multi-point grating optical cable according to an embodiment of the present invention.

FIG. 2 is a flow chart of a multi-point grating fiber optic cable temperature calibration method according to an embodiment of the present invention.

FIG. 3 is a graph showing the result of the FBG center wavelength-temperature acquisition and fitting in accordance with an embodiment of the invention.

FIG. 4 is a graph showing the result of fitting the temperature sensitivity of the grating according to the embodiment of the present invention.

Detailed Description

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "includes," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is explicitly stated. It should also be appreciated that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For ease of description, spatially relative terms, such as "inner," "outer," "lower," "upper," and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

Because the prior art lacks a method to be able to efficiently and accurately simultaneously scale the temperature sensitivity and thermal time constant of each FBG for long-distance fiber optic cables comprising multiple FBGs. The invention provides a multi-point grating optical cable temperature calibration device and a calibration method, wherein the device comprises a first optical cable reel, a second optical cable reel, a constant temperature box, a grating demodulator, a multi-point grating optical cable and a computer, wherein the first optical cable reel is used for winding and placing the multi-point grating optical cable to be calibrated, the second optical cable reel is used for receiving the multi-point grating optical cable which is released from the first optical cable reel and passes through the constant temperature box, the released multi-point grating optical cable is wound and arranged on the second optical cable reel, the constant temperature box is provided with through holes at least at two opposite sides, so that the multi-point grating optical cable can penetrate into a box body from one through hole and penetrate out of the box body from the other through hole, the grating demodulator is connected with the multi-point grating optical cable, and the computer is used for acquiring the reflection spectrum or central wavelength change data of all gratings in the multi-point grating optical cable along with time, fitting data acquired by the grating demodulator and processing the acquired data to acquire the temperature sensitivity and the thermal time constant of all gratings of the multi-point grating optical cable. Therefore, the invention can complete the calibration of the temperature sensitivity and the thermal time constant of each FBG in the optical cable at one time, and provides more comprehensive FBG temperature response characteristic parameters.

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The first embodiment is as shown in fig. 1, and the multi-point grating optical cable temperature calibration device provided by the embodiment comprises a first optical cable reel 1, a second optical cable reel 2, an incubator 3, a grating demodulator 4, a multi-point grating optical cable 5 and a computer 6, wherein:

A first optical cable reel 1 for winding and placing a multi-point grating optical cable 5 to be calibrated;

A second optical fiber reel 2 for receiving the multi-point grating optical fiber cable 5 released from the first optical fiber reel 1 and passing through the oven 3, and the released multi-point grating optical fiber cable 5 is wound on the second optical fiber reel 2.

The oven 3 is provided with through holes at least at two opposite sides, so that the multi-point grating optical cable 5 can penetrate into the oven body from one through hole and penetrate out of the oven body from the other through hole, wherein the oven 3 can stabilize the temperature inside the oven body at a plurality of preset target temperature points.

The grating demodulator 4 is connected with the multi-point grating optical cable 5 and is used for collecting the data of the change of the reflection spectrums or the central wavelengths of all FBGs in the multi-point grating optical cable 5 along with time at a high speed in real time.

And the computer 6 is used for acquiring data acquired by the grating demodulator 4 and fitting the acquired data of the change of the FBG reflection spectrum or the central wavelength along with time to acquire the temperature sensitivity and the thermal time constant of each FBG.

In a preferred embodiment of the present invention, both the first spool 1 and the second spool 2 may use either an electric spool or a manual spool in combination with a length metering device to achieve precise movement of the multi-point grating fiber optic cable 5 and FBG positioning.

In a preferred embodiment of the invention, the incubator 3 may use a high-low temperature tank, a water bath tank or a temperature control device capable of realizing a rapid temperature step, i.e. ensuring that the incubator 3 needs to have accurate temperature control capability.

Further, the number of the thermostats 3 may be set to be plural, and when plural thermostats 3 are provided, plural thermostats 3 may be set to different temperatures respectively by being set in series, so as to achieve a more complicated temperature profile or a faster temperature change.

Further, the dimensions of the oven 3 do not require any requirement, but it is necessary to ensure that at least one grating is located within the oven 3 during each time period.

Further, measures should be taken at the through hole of the incubator 3 to reduce heat dissipation, such as pore sealing using a flexible sealing material.

In a preferred embodiment of the present invention, the grating demodulator 4 can collect the center wavelength of all FBGs in the multi-point grating optical cable 5, the data collection frequency of which is selected depending on the thermal time constant of the cable, since the thermal time constants are related to the temperature gradient, e.g. the thermal time constant is different from 20 degrees to 30 degrees and from 20 degrees to 40 degrees, the relatively suitable data collection frequency is set to capture the details of the thermal response.

In a preferred embodiment of the invention, the grating demodulator 4 is fixed to the side wall of the first cable tray 1 and rotates synchronously with the first cable tray 1. The head end of the multi-point grating light 5 cable is connected to the grating demodulator 4 through the hole on the roller in the first optical cable tray 1 and extends to the side wall.

Further, the grating demodulator 4 sends the collected data to the computer 6 in real time in a wireless manner such as bluetooth or WiFi, and the grating demodulator 4 can also be connected with the computer 6 in a wired manner through an electrical slip ring and send the collected data to the computer 6 in real time.

In a second embodiment, as shown in fig. 2, the present embodiment further provides a method for calibrating the temperature of a multi-point grating optical cable, including:

S1, device connection and preparation.

In this embodiment, the multi-point grating optical cable 5 to be calibrated is wound on the first optical cable reel 1, the head end of the multi-point grating optical cable 5 extends to the side wall through the hole on the roller in the first optical cable reel 1, the grating demodulator 4 is fixed on the side wall of the first optical cable reel 1, the head end of the multi-point grating optical cable 5 is connected with the grating demodulator 4, and the tail end of the multi-point grating optical cable 5 is released from the first optical cable reel 1 and passes through the incubator 3 to be connected to the second optical cable reel 2.

S2, setting a first target temperature and stabilizing.

In the present embodiment, the temperature of the oven 3 is set to a first target temperature T₁ (for example, 30 ℃) and the temperature in the oven is waited for to stabilize, the temperature fluctuation is ensured to be within the allowable range, and the current target temperature T₁ is recorded.

S3, optical cable rotation and data acquisition.

In this embodiment, the optical cable rotation and data acquisition includes:

The second optical cable reel 2 is rotated to take up the multi-point grating optical cable 5, which is released from the first optical cable reel 1 and enters the incubator 3, the first FBG is placed in the incubator 3, then the grating demodulator 4 is turned on to record the center wavelength of the FBG (for example, but not limited to, one center wavelength is recorded every 1 second), and a sufficient time (for example, 2 times or more of the estimated maximum thermal time constant) is recorded to ensure that the FBG reaches the thermal balance, wherein the thermal balance means that the temperature of the optical cable has reached the temperature inside the incubator, for example, the ambient temperature is 20 degrees, the temperature of the optical cable is 20 degrees when the optical cable is just placed in the incubator, the incubator is set to 30 degrees, and the optical cable starts to heat up, and the thermal balance is reached when the temperature of the optical cable reaches 30 degrees.

The second optical cable reel 2 is rotated to take up the cable, so that the second FBG enters the incubator 3, and then the data acquisition process is repeated, so that all FBGs on the optical cable are acquired by data.

S4, repeating the temperature step and the data acquisition.

In this embodiment, the repeated temperature step and data acquisition includes:

First, the temperature of the oven 3 is set to the next target temperature T₂ (for example, 40 ℃) and stabilization is waited for.

Then, by reversely rotating the reels (e.g., rotating the first reel 1 to pay out the multi-point grating optical cable 5 from the second reel 2 and passing through the oven 3, repeating the data collection process of step S3, a plurality of target temperature points T₁,T₂,……,T_N (e.g., covering the use temperature range of the optical cable) may be set, and steps S2 and S3 may be repeated for each target temperature.

In this embodiment, besides the foregoing heating measurement of the FBG in the incubator 3, the FBG may be moved out of the incubator 3 to measure the dynamic response of the cooling process, which is not described herein.

S5, single-point single-temperature wavelength-time curve fitting.

In this embodiment, for each FBG collected from room temperature to one temperature stable process (e.g. from room temperature to T₁ or from room temperature to T₂, etc.), the change of its central wavelength with time is curve-fitted, e.g. from room temperature to T₁, the grating demodulator records a set of central wavelength data every 1 second, the central wavelength is λ_B(T₁,t₁ at time T₁, the central wavelength is λ_B(T₂,t₂ at time T₂), and so on, these data are curve-fitted, the time T is an independent variable, and λ_B (T, T) is a dependent variable, fitting is performed using the following formula:

;

Where λ_B (T, T) represents the FBG center wavelength at constant temperature T and time T, and a (T), b (T), and c (T) are fitting coefficients at constant temperature T. By fitting, the fitting coefficient of each FBG at a specific temperature can be obtained:

[ a (T₁),a(T₂),……,a(T_N)]、[b(T₁),b(T₂),……,b(T_N) ] and [ c (T₁),c(T₂),……,c(T_N) ].

S6, calibrating the grating temperature sensitivity.

In this embodiment, for each FBG, the stable center wavelength value c (T) after it reaches thermal equilibrium at different target temperatures is extracted, and the following linear fitting is performed with [ T₁,T₂,……,T_N ] as independent variable and [ c (T₁),c(T₂),……,c(T_N) ] as dependent variable:

;

where S is the temperature sensitivity of the FBG and K is a constant. By fitting each FBG, the temperature sensitivity of each FBG can be obtained.

S7, calibrating a thermal time constant.

In this embodiment, for a particular FBG, its thermal time constant τ is calculated by:

;

Where N is the number of measured temperature points, b (T_i) is the fitting coefficient of equation (1), and T_i is the measured temperature points.

The center wavelength data points and the linear fitting curves of certain FBGs after reaching thermal equilibrium at different target temperatures are shown in FIG. 3. A set of data was collected every 30 seconds, with thermostats stabilizing at 29.5 ℃, 39.0 ℃ and 48.6 ℃, respectively. The results of the parameter fitting are shown in table 1.

The coefficient C is fitted using equation (2), as shown in fig. 4, so that the temperature sensitivity of the grating is 10.1 pm/°c. The thermal time constant of the grating can be calculated to be 6.79 s/°c according to the coefficient b and formula (3).

In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In the description of the present specification, reference to the terms "one preferred embodiment," "further," "specifically," "in the present embodiment," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present specification. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present invention.

Claims (10)

Translated fromChinese

1.一种多点光栅光缆温度定标装置，其特征在于，该装置包括第一光缆盘、第二光缆盘、恒温箱、光栅解调仪、多点光栅光缆和计算机，其中：1. A multi-point grating optical cable temperature calibration device, characterized in that the device includes a first optical cable reel, a second optical cable reel, a constant temperature box, a grating demodulator, a multi-point grating optical cable and a computer, wherein:所述第一光缆盘，用于缠绕放置待定标的多点光栅光缆；The first optical cable reel is used for winding and placing the multi-point grating optical cable to be calibrated;所述第二光缆盘，用于接收从所述第一光缆盘释放且穿过所述恒温箱的多点光栅光缆，释放后的所述多点光栅光缆缠绕设置在所述第二光缆盘上；The second optical cable drum is used to receive the multi-point grating optical cable released from the first optical cable drum and passing through the constant temperature box, and the released multi-point grating optical cable is wound and arranged on the second optical cable drum;所述恒温箱，至少在相对的两侧开设有通孔，使得所述多点光栅光缆能够从一个通孔穿入箱体，从另一个通孔穿出箱体；The constant temperature box is provided with through holes on at least two opposite sides, so that the multi-point grating optical cable can pass through the box through one through hole and pass through the box through the other through hole;所述光栅解调仪，连接所述多点光栅光缆，用于实时采集所述多点光栅光缆中所有光栅的反射光谱或中心波长随时间的变化数据；The grating demodulator is connected to the multi-point grating optical cable and is used to collect the reflection spectrum or central wavelength change data of all gratings in the multi-point grating optical cable over time in real time;所述计算机，用于获取所述光栅解调仪采集的数据，并对采集数据进行拟合处理，获得所有的所述多点光栅光缆的光栅的温度灵敏度和热时间常数，具体为：The computer is used to obtain the data collected by the grating demodulator and perform fitting processing on the collected data to obtain the temperature sensitivity and thermal time constant of the gratings of all the multi-point grating cables, specifically:基于采集到的每个光栅若干目标温度下的反射光谱或中心波长的随时间的变化数据进行单点单温度波长-时间曲线拟合，得到拟合系数[b(T₁),b(T₂),……,b(T_N)]和[c(T₁),c(T₂),……,c(T_N)]；Based on the collected data of the reflection spectrum or central wavelength variation over time at several target temperatures of each grating, a single-point single-temperature wavelength-time curve fitting is performed to obtain the fitting coefficients [b(T₁ ), b(T₂ ), …, b(_TN )] and [c(T₁ ), c(T₂ ), …, c(_TN )];对于每个光栅，以恒温箱设定的若干目标温度[T₁,T₂,……,T_N]为自变量、拟合系数[c(T₁),c(T₂),……,c(T_N)]为因变量进行线性拟合得到该光栅的温度灵敏度，具体公式为：For each grating, a linear fit is performed with several target temperatures [T₁ , T₂ , …, T_N ] set in the constant temperature box as independent variables and fitting coefficients [c(T₁ ), c(T₂ ), …, c(T_N )] as dependent variables to obtain the temperature sensitivity of the grating. The specific formula is:式中，S为该光栅的温度灵敏度，K为常数；Where S is the temperature sensitivity of the grating, and K is a constant;对于每个光栅，基于拟合系数[b(T₁),b(T₂),……,b(T_N)]和测量的温度点[T₁,T₂,……,T_N]，计算得到该光栅的热时间常数τ，具体公式为：For each grating, the thermal time constant τ of the grating is calculated based on the fitting coefficients [b(T₁ ), b(T₂ ), …, b(_TN )] and the measured temperature points [T₁ , T₂ , …,_TN ]. The specific formula is:； ;式中，N为测量的温度点数量，T_i为测量的温度点。Where N is the number of measured temperature points and_Ti is the measured temperature point.2.根据权利要求1所述的多点光栅光缆温度定标装置，其特征在于，所述恒温箱具有精确的温度控制能力，能够将箱体内部温度稳定在多个预设的目标温度点，其中所述恒温箱的数量设置有多个，多个所述恒温箱通过串联设置，能够分别设定不同的温度，以实现更复杂的温度剖面或更快的温度变化。2. The multi-point grating optical cable temperature calibration device according to claim 1 is characterized in that the constant temperature box has precise temperature control capabilities and can stabilize the temperature inside the box at multiple preset target temperature points, wherein there are multiple constant temperature boxes, and the multiple constant temperature boxes are arranged in series to set different temperatures respectively to achieve more complex temperature profiles or faster temperature changes.3.根据权利要求1所述的多点光栅光缆温度定标装置，其特征在于，所述光栅解调仪固定在所述第一光缆盘的侧壁上，随所述第一光缆盘同步转动，所述多点光栅光缆的首端通过所述第一光缆盘内滚筒上的孔伸出到侧壁处连接所述光栅解调仪上，所述光栅解调仪通过有线或无线方式将采集的数据发送到所述计算机。3. The multi-point grating optical cable temperature calibration device according to claim 1 is characterized in that the grating interrogator is fixed to the side wall of the first optical cable drum and rotates synchronously with the first optical cable drum. The head end of the multi-point grating optical cable extends out to the side wall through the hole on the inner drum of the first optical cable drum and is connected to the grating interrogator. The grating interrogator sends the collected data to the computer via wired or wireless means.4.根据权利要求1所述的多点光栅光缆温度定标装置，其特征在于，所述通孔处还使用柔性密封材料进行空隙密封，减少热量散失。4. The multi-point grating optical cable temperature calibration device according to claim 1, characterized in that a flexible sealing material is used to seal the gap at the through hole to reduce heat loss.5.根据权利要求1所述的多点光栅光缆温度定标装置，其特征在于，所述第一光缆盘和第二光缆盘均使用电动光缆盘或手动光缆盘配合长度计量装置来实现所述多点光栅光缆的精确移动和光栅定位。5. The multi-point grating optical cable temperature calibration device according to claim 1 is characterized in that the first optical cable reel and the second optical cable reel both use electric optical cable reels or manual optical cable reels in conjunction with a length measuring device to achieve precise movement and grating positioning of the multi-point grating optical cable.6.一种基于权利要求1～5任一项所述的多点光栅光缆温度定标装置的定标方法，其特征在于，包括：6. A calibration method based on the multi-point grating cable temperature calibration device according to any one of claims 1 to 5, characterized by comprising:将所述多点光栅光缆温度定标装置的所有器件按照要求进行安装固定；Install and fix all components of the multi-point grating cable temperature calibration device as required;将所述恒温箱的温度设定为第一个目标温度T₁，并等待所述恒温箱的箱体内温度稳定，所述光栅解调仪实时采集位于所述恒温箱内的光栅的反射光谱或中心波长随时间的变化数据；转动所述第二光缆盘收缆，使所述多点光栅光缆从所述第一光缆盘释放出并穿过所述恒温箱；将所述恒温箱的温度设定为下一个目标温度T₂，等待稳定后，反向转动光缆盘使所述多点光栅光缆从所述第二光缆盘释放出并穿过所述恒温箱，以此类推，设定多个目标温度点T_N，并针对每个目标温度重复测量，得到若干目标温度下的所有光栅的反射光谱或中心波长的随时间的变化数据；The temperature of the constant temperature box is set to a first target temperature T₁ , and the temperature inside the constant temperature box is waited for stabilization, and the grating interrogator collects the reflection spectrum or central wavelength variation data of the grating located in the constant temperature box in real time; the second optical cable drum is rotated to reel in the cable, so that the multi-point grating optical cable is released from the first optical cable drum and passes through the constant temperature box; the temperature of the constant temperature box is set to the next target temperature T₂ , and after stabilization, the optical cable drum is rotated in the opposite direction so that the multi-point grating optical cable is released from the second optical cable drum and passes through the constant temperature box. Similarly, multiple target temperature points T_N are set, and the measurement is repeated for each target temperature to obtain the reflection spectrum or central wavelength variation data of all gratings at the target temperatures.基于采集到的每个光栅若干目标温度下的反射光谱或中心波长的随时间的变化数据进行单点单温度波长-时间曲线拟合，得到拟合系数[b(T₁),b(T₂),……,b(T_N)]和[c(T₁),c(T₂),……,c(T_N)]；Based on the collected data of the reflection spectrum or central wavelength variation over time at several target temperatures of each grating, a single-point single-temperature wavelength-time curve fitting is performed to obtain the fitting coefficients [b(T₁ ), b(T₂ ), …, b(_TN )] and [c(T₁ ), c(T₂ ), …, c(_TN )];对于每个光栅，以[T₁,T₂,……,T_N]为自变量、拟合系数[c(T₁),c(T₂),……,c(T_N)]为因变量进行线性拟合得到该光栅的温度灵敏度；For each grating, a linear fit is performed with [T₁ , T₂ , …, T_N ] as the independent variable and the fitting coefficient [c(T₁ ), c(T₂ ), …, c(T_N )] as the dependent variable to obtain the temperature sensitivity of the grating;对于每个光栅，基于拟合系数[b(T₁),b(T₂),……,b(T_N)]和测量的温度点[T₁,T₂,……,T_N]，计算得到该光栅的热时间常数τ。For each grating, the thermal time constant τ of the grating is calculated based on the fitting coefficients [b(T₁ ), b(T₂ ), ..., b(_TN )] and the measured temperature points [T₁ , T₂ , ...,_TN ].7.根据权利要求6所述的定标方法，其特征在于，将多点光栅光缆温度定标装置的所有器件进行安装固定，包括：7. The calibration method according to claim 6, characterized in that all components of the multi-point grating cable temperature calibration device are installed and fixed, comprising:将待定标的所述多点光栅光缆缠绕盘放在所述第一光缆盘上，所述多点光栅光缆的首端通过所述第一光缆盘内滚筒上的孔伸出到侧壁处，所述光栅解调仪固定在所述第一光缆盘的侧壁上，将所述多点光栅光缆的首端与所述光栅解调仪连接，将所述多点光栅光缆的尾端从所述第一光缆盘上释放并穿过所述恒温箱连接到所述第二光缆盘。The multi-point grating optical cable winding reel to be calibrated is placed on the first optical cable reel. The head end of the multi-point grating optical cable extends to the side wall through the hole on the inner drum of the first optical cable reel. The grating demodulator is fixed on the side wall of the first optical cable reel. The head end of the multi-point grating optical cable is connected to the grating demodulator. The tail end of the multi-point grating optical cable is released from the first optical cable reel and connected to the second optical cable reel through the constant temperature box.8.根据权利要求6所述的定标方法，其特征在于，基于采集到的每个光栅若干目标温度下的反射光谱或中心波长的随时间的变化数据进行单点单温度波长-时间曲线拟合，得到拟合系数，具体为：8. The calibration method according to claim 6, characterized in that a single-point single-temperature wavelength-time curve fitting is performed based on the collected data of the reflection spectrum or central wavelength variation over time at several target temperatures of each grating to obtain a fitting coefficient, specifically:式中，λ_B(T,t)表示恒温T、时刻t的光栅中心波长，a(T)、b(T)、c(T)为恒温T下的拟合系数，通过拟合能够获得每个光栅在目标温度下的拟合系数：[a(T₁),a(T₂),……,a(T_N)]、[b(T₁),b(T₂),……,b(T_N)]和[c(T₁),c(T₂),……,c(T_N)]。where λ_B (T, t) represents the central wavelength of the grating at constant temperature T and time t, a(T), b(T), and c(T) are the fitting coefficients at constant temperature T. The fitting coefficients of each grating at the target temperature can be obtained by fitting: [a(T₁ ), a(T₂ ), …, a(_TN )], [b(T₁ ), b(T₂ ), …, b(_TN )], and [c(T₁ ), c(T₂ ), …, c(_TN )].9.根据权利要求8所述的定标方法，其特征在于，对于每个光栅，以[T₁,T₂,……,T_N]为自变量、拟合系数[c(T₁),c(T₂),……,c(T_N)]为因变量进行线性拟合得到该光栅的温度灵敏度，具体公式为：9. The calibration method according to claim 8, characterized in that for each grating, a linear fit is performed with [T₁ , T₂ , ..., T_N ] as the independent variable and the fitting coefficient [c(T₁ ), c(T₂ ), ..., c(T_N )] as the dependent variable to obtain the temperature sensitivity of the grating, and the specific formula is:式中，S为该光栅的温度灵敏度，K为常数。Where S is the temperature sensitivity of the grating and K is a constant.10.根据权利要求9所述的定标方法，其特征在于，对于每个光栅，基于拟合系数[b(T₁),b(T₂),……,b(T_N)]和测量的温度点[T₁,T₂,……,T_N]，计算得到该光栅的热时间常数τ，具体公式为：10. The calibration method according to claim 9, characterized in that for each grating, the thermal time constant τ of the grating is calculated based on the fitting coefficients [b(T₁ ), b(T₂ ), ..., b(_TN )] and the measured temperature points [T₁ , T₂ , ...,_TN ], and the specific formula is:； ;式中，N为测量的温度点数量，T_i为测量的温度点。Where N is the number of measured temperature points and_Ti is the measured temperature point.