Collective distributed fiber optic sensor

Abstract

This disclosure relates to a distributed optical fiber sensor, in which a beam splitting coupling unit is used to: split the light emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to a temperature source, and transmit a first modulated signal obtained by modulating the first optical signal by the temperature source to a first photoelectric processing unit; transmit the second optical signal to a strain source, and transmit a second modulated signal obtained by modulating the second optical signal by the strain source to a second photoelectric processing unit; and then a data analysis unit determines the temperature data of the temperature source and the strain data of the strain source. This improves the accuracy of the optical fiber sensor in detecting temperature and strain.

Description

Technical Field

[0001] This disclosure relates to the field of fiber optic sensing technology, and more particularly to a distributed fiber optic sensor. Background Technology

[0002] With the rapid development of industrial automation and intelligent monitoring, the demand for accurate and real-time monitoring of physical quantities such as temperature and strain is becoming increasingly urgent. Fiber optic sensors, due to their significant advantages such as resistance to electromagnetic interference, corrosion resistance, small size, light weight, and the ability to achieve distributed measurement, have been widely used in many fields such as bridges, buildings, power equipment, and petrochemicals.

[0003] Currently, in scenarios requiring simultaneous monitoring of temperature and strain, the common approach is to deploy separate temperature fiber optic sensors and strain fiber optic sensors. While this separate monitoring solution can achieve basic measurement functions, it has several drawbacks: Firstly, the two independent sensor systems require separate configurations of light sources, photoelectric processing components, etc., resulting in a larger overall equipment size and more complex structure, increasing installation space requirements and deployment difficulty; secondly, the cost of independent systems is high, and time deviations are prone to occur during synchronous acquisition and data correlation analysis, affecting the consistency and accuracy of measurements.

[0004] Furthermore, some existing integrated fiber optic sensing solutions suffer from suboptimal design in optical signal distribution and processing, often resulting in significant optical signal loss and low signal-to-noise ratio, which in turn affects measurement accuracy. Simultaneously, their photoelectric processing units lack sufficient signal preprocessing capabilities, making it difficult to effectively filter out noise interference, thus reducing the reliability of subsequent data analysis results.

[0005] Therefore, how to improve the accuracy of fiber optic sensors in detecting temperature and strain has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, in order to solve some or all of the above-mentioned technical problems, this disclosure provides a distributed optical fiber sensor.

[0007] In a first aspect, embodiments of this disclosure provide a modular fiber optic sensor, comprising a light source emitting unit, a beam splitting and coupling unit, a first photoelectric processing unit, a second photoelectric processing unit, and a data analysis unit; the beam splitting and coupling unit is connected to the light source emitting unit, the first photoelectric processing unit, and the second photoelectric processing unit respectively via single-mode optical fiber; the data analysis unit is electrically connected to the first photoelectric processing unit and the second photoelectric processing unit respectively; wherein:

[0008] The beam splitting coupling unit is used to: split the light source emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to a temperature source, and transmit a first modulated signal obtained by modulating the first optical signal by the temperature source to a first photoelectric processing unit; transmit the second optical signal to a strain source, and transmit a second modulated signal obtained by modulating the second optical signal by the strain source to a second photoelectric processing unit.

[0009] The first photoelectric processing unit is used to: preprocess the first modulation signal to obtain a first preprocessed signal; and transmit the first preprocessed signal to the data analysis unit.

[0010] The second photoelectric processing unit is used to: preprocess the second modulation signal to obtain a second preprocessed signal; and transmit the second preprocessed signal to the data analysis unit.

[0011] The data analysis unit is used to: determine the temperature data of the temperature source based on the first preprocessed signal; and determine the strain data of the strain source based on the second preprocessed signal.

[0012] In some possible implementations, the optical splitting coupling unit includes a first subunit, a second subunit, and a third subunit;

[0013] The first subunit is connected to the light source emitting unit and the second subunit respectively;

[0014] The second subunit is also connected to the temperature source and the first photoelectric processing unit;

[0015] The third subunit is also connected to the strain source and the second photoelectric processing unit;

[0016] The first subunit is used to: split the light source emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to the second subunit; and transmit the second optical signal to the third subunit.

[0017] The second subunit is used to: transmit the first optical signal to the temperature source, and transmit the first modulated signal obtained by the temperature source modulating the first optical signal to the first photoelectric processing unit.

[0018] The third subunit is used to: transmit the second optical signal to the strain source, and transmit the second modulated signal obtained by modulating the second optical signal by the strain source to the second photoelectric processing unit.

[0019] In some possible implementations,

[0020] The first subunit includes a first beam splitter, a first coupler, a second coupler, and a third coupler;

[0021] The second subunit includes a second beam splitter, a fourth coupler, a fifth coupler, and a sixth coupler;

[0022] The third subunit includes the third beam splitter, the seventh coupler, the eighth coupler, and the ninth coupler;

[0023] The first end of the first beam splitter is connected to the light source emitting unit through the first coupler, the second end of the first beam splitter is connected to the fourth coupler through the second coupler, and the third end of the first beam splitter is connected to the seventh coupler through the third coupler.

[0024] The first end of the second beam splitter is connected to the fourth coupler, the second end of the second beam splitter is connected to the temperature source through the fifth coupler, and the third end of the second beam splitter is connected to the first photoelectric processing unit through the sixth coupler.

[0025] The first end of the third beam splitter is connected to the seventh coupler, the second end of the third beam splitter is connected to the strain source through the eighth coupler, and the third end of the third beam splitter is connected to the second photoelectric processing unit through the ninth coupler.

[0026] In some possible implementations, the first preprocessed signal includes the Stokes intensity and anti-Stokes intensity of the back-scattered Raman light; and

[0027] The data analysis unit is used for:

[0028] Determine the ratio of Stokes intensity to anti-Stokes intensity;

[0029] Temperature data of the temperature source is determined based on the ratio.

[0030] In some possible implementations, the second preprocessed signal includes a wavelength shift of the backscattered Rayleigh light; and

[0031] The data analysis unit is used for:

[0032] Based on wavelength shift, the strain data of the strain source is determined.

[0033] In some possible implementations,

[0034] The first optoelectronic processing unit includes a first photodiode, a first driver board for the first photodiode, a first voltage amplifier, and a first development board connected in sequence.

[0035] The second optoelectronic processing unit includes a second photodiode, a second driver board for the second photodiode, a second voltage amplifier, and a second development board connected in sequence.

[0036] The first photodiode is used to: convert the first modulation signal into a first electrical signal; and transmit the first electrical signal to the first voltage amplifier via the first driver board.

[0037] The first voltage amplifier is used to: amplify the first electrical signal to obtain a first amplified signal; and transmit the first amplified signal to the first development board.

[0038] The first development board is used to: extract the Stokes intensity and anti-Stokes intensity of the backscattered Raman light from the first amplified signal; and generate a first preprocessed signal based on the Stokes intensity and anti-Stokes intensity.

[0039] The second photodiode is used to: convert the second modulation signal into a second electrical signal; and transmit the second electrical signal to the second voltage amplifier via the second driver board.

[0040] The second voltage amplifier is used to: amplify the second electrical signal to obtain a second amplified signal; and transmit the second amplified signal to the second development board.

[0041] The second development board is used to: extract the wavelength shift of the backscattered Rayleigh light from the second amplified signal; and generate a second preprocessed signal based on the wavelength shift.

[0042] In some possible implementations, the first photodiode, the first driving board, the second photodiode, and the second driving board are disposed in a dark box.

[0043] In some possible implementations, the first photodiode, the first driver board, the first voltage amplifier, the second photodiode, the second driver board, and the second voltage amplifier are disposed in a constant temperature chamber.

[0044] In some possible implementations, the first voltage amplifier and the second voltage amplifier have an input impedance of 5 megohms and an output impedance of 100 ohms, respectively.

[0045] In some possible implementations, the light source emitting unit is used to emit a light source with a wavelength of 1550 nanometers in a preset constant temperature environment.

[0046] The integrated fiber optic sensor provided in this disclosure includes a light source emitting unit, a beam splitting coupling unit, a first photoelectric processing unit, a second photoelectric processing unit, and a data analysis unit. The beam splitting coupling unit is connected to the light source emitting unit, the first photoelectric processing unit, and the second photoelectric processing unit via single-mode optical fibers. The data analysis unit is electrically connected to both the first and second photoelectric processing units. The beam splitting coupling unit is used to: split the light emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to a temperature source; and transmit a first modulated signal obtained by modulating the first optical signal with the temperature source to a first... The system includes a photoelectric processing unit; a first photoelectric processing unit transmits a second optical signal to a strain source, and a second modulated signal obtained by modulating the second optical signal by the strain source is transmitted to a second photoelectric processing unit. The first photoelectric processing unit preprocesses the first modulated signal to obtain a first preprocessed signal and transmits the first preprocessed signal to a data analysis unit. The second photoelectric processing unit preprocesses the second modulated signal to obtain a second preprocessed signal and transmits the second preprocessed signal to the data analysis unit. The data analysis unit determines the temperature data of the temperature source based on the first preprocessed signal and determines the strain data of the strain source based on the second preprocessed signal. Therefore, the light emitted by the same light source emitting unit can be split into two optical signals, transmitted via single-mode fiber, and modulated by the temperature source and strain source, then preprocessed separately by independent photoelectric processing units. Finally, the data analysis unit determines the temperature data of the temperature source and the strain data of the strain source, thereby improving the accuracy of the fiber optic sensor in detecting temperature and strain. Attached Figure Description

[0047] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0048] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0050] Figure 1 This is a schematic diagram of the structure of an integrated fiber optic sensor provided in an embodiment of the present disclosure;

[0051] Figure 2 A schematic diagram of the scattering spectrum in an integrated fiber optic sensor provided in an embodiment of this disclosure;

[0052] Figure 3 A schematic diagram showing the connection of a photodiode, a driver board, a voltage amplifier, and a development board in an integrated fiber optic sensor provided in this embodiment of the disclosure;

[0053] Figure 4 This is a schematic diagram of another integrated fiber optic sensor provided in an embodiment of the present disclosure. Detailed Implementation

[0054] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It is obvious that the described embodiments are only a part of, and not all, of the embodiments described herein. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0055] Those skilled in the art will understand that the terms "first" and "second" in the embodiments of this disclosure are only used to distinguish different steps, devices or modules, and do not represent any specific technical meaning, nor do they indicate the logical order between them.

[0056] It should also be understood that in this embodiment, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0057] It should also be understood that any component, data or structure mentioned in the embodiments of this disclosure can generally be understood as one or more unless expressly defined or given to the contrary in the context.

[0058] Furthermore, the term "and / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0059] It should also be understood that the description of the various embodiments in this disclosure emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0060] The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit the scope of this disclosure or its application or use.

[0061] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0062] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. To facilitate understanding of the embodiments of this disclosure, the disclosure will be described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0064] To address the technical problem of how to improve the accuracy of fiber optic sensors in detecting temperature and strain in the prior art, this disclosure provides a collection of distributed fiber optic sensors that can improve the accuracy of fiber optic sensors in detecting temperature and strain.

[0065] Figure 1 This is a schematic diagram of a structure for an integrated distributed optical fiber sensor provided in an embodiment of this disclosure. Figure 1 As shown, the integrated fiber optic sensor includes a light source emitting unit 10, a beam splitting coupling unit 20, a first photoelectric processing unit 30, a second photoelectric processing unit 40, and a data analysis unit 50.

[0066] The beam splitting coupling unit 20 is connected to the light source emitting unit 10, the first photoelectric processing unit 30, and the second photoelectric processing unit 40 via single-mode optical fibers.

[0067] The data analysis unit 50 is electrically connected to the first photoelectric processing unit 30 and the second photoelectric processing unit 40, respectively.

[0068] The light source emitting unit 10 is used to emit a light source.

[0069] In some cases, the light source emitting unit 10 can be used to emit a light source of a preset wavelength.

[0070] The beam splitting coupling unit 20 is used to: split the light emitted by the light source emitting unit 10 into a first optical signal and a second optical signal; transmit the first optical signal to the temperature source 60; and transmit a first modulated signal obtained by the temperature source 60 modulating the first optical signal to the first photoelectric processing unit 30. The second optical signal is transmitted to the strain source 70; and the second modulated signal obtained by the strain source 70 modulating the second optical signal is transmitted to the second photoelectric processing unit 40.

[0071] The first photoelectric processing unit 30 is used to: preprocess the first modulation signal to obtain a first preprocessed signal; and transmit the first preprocessed signal to the data analysis unit 50.

[0072] The second photoelectric processing unit 40 is used to: preprocess the second modulation signal to obtain a second preprocessed signal; and transmit the second preprocessed signal to the data analysis unit 50.

[0073] The data analysis unit 50 is used to: determine the temperature data of the temperature source 60 based on the first preprocessed signal; and determine the strain data of the strain source 70 based on the second preprocessed signal.

[0074] The light source emitting unit 10 is a device capable of emitting specific optical signals, which can provide an optical signal source for the entire system. For example, the light source emitting unit 10 can be a distributed feedback laser (DFBLaser).

[0075] The beam splitting coupling unit 20 is used to distribute and transmit optical signals. It can split the light source into two optical signals and transmit them, while simultaneously transmitting the modulated signal to the corresponding optoelectronic processing unit.

[0076] The first optoelectronic processing unit 30 can process and convert the received optical signal, converting it into an electrical signal and performing preprocessing. Here, the first optoelectronic processing unit 30 can process (e.g., amplify, convert analog to digital, denoise, etc.) the first modulation signal from the temperature source. In some cases, the first optoelectronic processing unit 30 can also receive and process the first optical signal.

[0077] The function of the second optoelectronic processing unit 40 is similar to that of the first optoelectronic processing unit 30. Its main processing (e.g., amplification, analog-to-digital conversion, noise reduction, etc.) is the second modulation signal from the strain source. In some cases, the second optoelectronic processing unit 40 can also receive and process a second optical signal.

[0078] The data analysis unit 50 can analyze and calculate the received electrical signals (e.g., the first preprocessed signal, the second preprocessed signal, the first optical signal, and the second optical signal) to obtain the required physical quantity data, such as Stokes intensity, anti-Stokes intensity, and wavelength shift. As an example, the data analysis unit 50 can be a computer.

[0079] Single-mode fiber (SMF) is a type of optical fiber that can only transmit optical signals in one mode. It can be used for optical signal transmission between units, ensuring the stability and accuracy of optical signal transmission.

[0080] Temperature source 60 is an object or environment capable of generating temperature changes and modulating the first optical signal. In this scheme, the characteristics of the first optical signal will change due to temperature changes when it passes through the temperature source. For example, temperature source 60 can be a high-temperature reactor, indoor air, etc.

[0081] The strain source 70 is an object or structure capable of generating strain and modulating the second optical signal. When the second optical signal passes through the strain source, its characteristics change due to the deformation of the object. For example, the strain source 70 can be a bridge beam, a mechanical drive shaft, etc.

[0082] here, Figure 1 Temperature source 60 and strain source 70, represented by dashed lines, do not belong to the distributed fiber optic sensor cluster.

[0083] The first optical signal is a light signal split off from the light source emitted by the light source emitting unit 10 by the beam splitting coupling unit 20, and is specifically used to transmit to the temperature source for temperature-related modulation.

[0084] The second optical signal is an optical signal split off by another optical splitting coupling unit 20, which is used to transmit to the strain source for strain-related modulation.

[0085] The first modulation signal is the optical signal whose characteristics are changed by temperature after the first optical signal passes through the temperature source.

[0086] The second modulation signal is the optical signal whose characteristics are changed by the strain after the second optical signal passes through the strain source.

[0087] The first preprocessed signal is the signal obtained by the first photoelectric processing unit 30 after processing the first modulated signal (e.g., signal amplification, noise reduction, extraction of Stokes intensity and anti-Stokes intensity of backscattered Raman light, etc.), which provides the basis for temperature calculation for the data analysis unit 50.

[0088] The second preprocessed signal is the signal obtained after the second photoelectric processing unit 40 processes the second modulated signal (e.g., signal amplification, noise reduction, extraction of wavelength shift of back Rayleigh scattering light, etc.), providing the basis for strain calculation for the data analysis unit 50.

[0089] Temperature data characterizes the magnitude of the temperature source.

[0090] Strain data characterizes the magnitude of strain at the strain source.

[0091] Here, the beam splitting coupling unit 20 can split the incident light into two beams in a certain proportion through the optical structure inside the beam splitter, such as a prism or grating, thereby obtaining the first optical signal and the second optical signal.

[0092] Furthermore, in a temperature source, temperature changes can alter the refractive index and other properties of a single-mode fiber, thereby modulating the intensity and phase of the first optical signal; in a strain source, deformation of an object can stretch or compress a single-mode fiber, thereby modulating the wavelength of the second optical signal.

[0093] Preprocessing may include, for example, removing noise by using filtering methods, such as using a bandpass filter to retain optical signals of a specific wavelength; and signal amplification, which enhances weak optical signals through an amplifier for subsequent processing.

[0094] Here, the temperature data of the temperature source can be obtained by looking up the signal characteristics of the first preprocessed signal in a preset first table (e.g., Table 1); or the temperature data of the temperature source can be calculated based on the signal parameters of the first preprocessed signal by substituting the parameters into a calculation formula (e.g., Formula 1). Furthermore, the strain value of the strain source can be obtained by looking up the strain values ​​of the second preprocessed signal in a preset second table (e.g., Table 2).

[0095] Therefore, this scheme uses a beam splitting coupling unit to split the same light source into two optical signals, one for temperature and one for strain measurement, sharing a single light source emission unit and data analysis unit. This eliminates the need for separate light source emission units and data analysis units for each parameter, simplifying the structure, reducing size, and lowering cost. Furthermore, since both signals originate from the same light source and are processed synchronously, time deviations caused by different light sources and processing units are avoided, thus improving measurement consistency and accuracy. In this way, this scheme enables simultaneous temperature and strain measurement, simplifying the equipment structure, reducing size, lowering cost, and improving measurement consistency and accuracy.

[0096] In some optional implementations of this embodiment, the optical splitting coupling unit 20 includes a first subunit, a second subunit, and a third subunit.

[0097] The first subunit is connected to the light source emitting unit 10 and the second subunit, respectively.

[0098] The second subunit is also connected to the temperature source 60 and the first photoelectric processing unit 30.

[0099] The third subunit is also connected to the strain source 70 and the second photoelectric processing unit 40.

[0100] The first subunit is used to: split the light source emitted by the light source emitting unit 10 into a first optical signal and a second optical signal; transmit the first optical signal to the second subunit; and transmit the second optical signal to the third subunit.

[0101] The second subunit is used to: transmit the first optical signal to the temperature source 60, and transmit the first modulated signal obtained by the temperature source 60 modulating the first optical signal to the first photoelectric processing unit 30.

[0102] The third subunit is used to: transmit the second optical signal to the strain source 70, and transmit the second modulated signal obtained by the strain source 70 modulating the second optical signal to the second photoelectric processing unit 40.

[0103] The first subunit is the part of the beam splitting coupling unit 20 responsible for splitting the light source into two optical signals and transmitting them to the second and third subunits respectively. It can play the role of initial beam splitting and signal distribution.

[0104] The second subunit connects the first subunit, the temperature source 60, and the first photoelectric processing unit 30, and is responsible for the transmission of the first optical signal and the feedback of the first modulation signal. Here, the second subunit ensures the orderly transmission of temperature measurement-related optical signals.

[0105] The third subunit connects the first subunit, the strain source 70, and the second photoelectric processing unit 40, and is responsible for the transmission of the second optical signal and the feedback of the second modulation signal. Here, it can ensure the orderly transmission of the optical signals related to strain measurement.

[0106] Here, fixed connections between units can be achieved through fiber optic fusion splicing to ensure low loss in optical signal transmission; alternatively, detachable connections can be made through fiber optic connectors to facilitate equipment maintenance and replacement.

[0107] In addition to using a beam splitter, the principle of light interference can also be utilized to split the light signal into different optical path signals using an interferometer.

[0108] It is understood that in the above optional implementation methods, the beam splitting coupling unit includes three sub-units, and each sub-unit has a clear division of labor. The first sub-unit is responsible for the initial beam splitting, and the second and third sub-units are responsible for the signal transmission of the temperature and strain branches, respectively. This structured design makes the distribution and transmission path of optical signals clear, reduces signal interference and loss, and thus improves the accuracy and stability of optical signal distribution and transmission.

[0109] Please continue reading Figure 4 , Figure 4 This is a schematic diagram of another integrated fiber optic sensor provided in an embodiment of the present disclosure.

[0110] In some application scenarios of the above optional implementation methods, the first sub-unit includes a first beam splitter 211, a first coupler 221, a second coupler 222, and a third coupler 223.

[0111] The second subunit includes a second beam splitter 212, a fourth coupler 224, a fifth coupler 225, and a sixth coupler 226.

[0112] The third subunit includes a third beam splitter 213, a seventh coupler 227, an eighth coupler 228, and a ninth coupler 229.

[0113] The first end of the first beam splitter 211 is connected to the light source emitting unit 10 through the first coupler 221, the second end of the first beam splitter 211 is connected to the fourth coupler 224 through the second coupler 222, and the third end of the first beam splitter 211 is connected to the seventh coupler 227 through the third coupler 223.

[0114] The first end of the second beam splitter 212 is connected to the fourth coupler 224, the second end of the second beam splitter 212 is connected to the temperature source 60 through the fifth coupler 225, and the third end of the second beam splitter 212 is connected to the first photoelectric processing unit 30 through the sixth coupler 226.

[0115] The first end of the third beam splitter 213 is connected to the seventh coupler 227, the second end of the third beam splitter 213 is connected to the strain source 70 through the eighth coupler 228, and the third end of the third beam splitter 213 is connected to the second photoelectric processing unit 40 through the ninth coupler 229.

[0116] The first beam splitter 211 is an optical device that can distribute a single optical signal to multiple outputs in a certain ratio (e.g., 1:1). Here, the first beam splitter 211 is responsible for splitting the light source from the light source emitting unit 10 into two paths, which are then sent to the second sub-unit and the third sub-unit, respectively, to provide the basic optical signal for subsequent synchronous measurement of temperature and strain.

[0117] The second beam splitter 212 is mainly used in the second subunit to further distribute and control the transmission of the first optical signal transmitted from the first subunit. It can transmit the first optical signal to the temperature source 60 and the first photoelectric processing unit 30 respectively, ensuring the smooth operation of the temperature measurement optical path.

[0118] The third beam splitter 213 is applied to the third sub-unit and is responsible for distributing the second optical signal transmitted from the first sub-unit to the strain source 70 and the second photoelectric processing unit 40 respectively, so as to ensure the stability of the strain measurement optical path.

[0119] First coupler 221, second coupler 222, third coupler 223, fourth coupler 224, fifth coupler 225, sixth coupler 226, seventh coupler 227, eighth coupler 228, and ninth coupler 229 are devices that enable the coupling and transmission of optical signals between different optical fibers. They can be used for optical signal connections between various optical splitters and other components, reducing optical signal loss during transmission and ensuring efficient optical signal transmission.

[0120] Here, fiber optic fusion splicing technology can be used, which melts the end faces of optical fibers at high temperatures and then connects them together. This method has low connection loss and high stability. Alternatively, fiber optic movable connectors can be used, which can be connected by plugging and unplugging, making it easier to maintain and replace the equipment.

[0121] Optical signals are mainly transmitted through single-mode optical fibers, utilizing the principle of total internal reflection to transmit within the fiber.

[0122] Understandably, in the above application scenarios, the structure of the beam splitting and coupling unit is clear and highly feasible. Each beam splitter and coupler has a clearly defined function, and the optical signal transmission path is fixed, reducing the loss and interference of optical signals during transmission. This ensures the stability and efficiency of optical signal distribution and transmission, further improving the overall performance of the sensor.

[0123] In some optional implementations of this embodiment, the first preprocessed signal includes the Stokes intensity and the anti-Stokes intensity of the backscattered Raman light.

[0124] See Figure 2 , Figure 2 This is a schematic diagram of the scattering spectrum in an integrated fiber optic sensor provided in an embodiment of this disclosure. The spectra of backscattered Raman light, backscattered Rayleigh light, and Brillouin scattering are shown in the figure.

[0125] The data analysis unit 50 is used to: determine the ratio of Stokes light intensity to anti-Stokes light intensity; and determine the temperature data of the temperature source 60 based on the ratio.

[0126] Backscattered Raman light is scattered light produced when photons exchange energy during the interaction of light with molecules in matter, resulting in a change in its frequency. Here, backscattered Raman light carries temperature information, and temperature data can be obtained through its analysis.

[0127] In Raman scattering, the Stokes intensity is the intensity of the scattered light produced when a photon loses energy and its frequency decreases. The anti-Stokes intensity is the intensity of the scattered light produced when a photon gains energy and its frequency increases.

[0128] Here, the corresponding temperature data can be found by referring to the pre-established table of the correspondence between ratio and temperature (see Table 1); or the temperature data can be calculated by substituting the values ​​into a preset formula (see Formula 1).

[0129] Specifically, Stokes intensity I S With anti-Stokes intensity I AS The relationship between the ratio and absolute temperature T is as follows: .

[0130] Where exp() represents the exponential function; K represents the energy change of a photon, which is the product of Planck's constant and the frequency of light; B This represents the Boltzmann constant.

[0131] In practical applications, the relationship is approximately linear (within a certain temperature range) through experimental fitting: Where a and c are The fitting parameters are determined from the experimental data.

[0132] Therefore, the temperature data of the temperature source can be determined based on the above ratios using Table 1.

[0133] Temperature (°C) <![CDATA[Stokes light intensity I S (relative value)]]> <![CDATA[Anti-Stokes light intensity I AS (relative value)]]> <![CDATA[Ratio I AS / I S > 15 186 37.2 0.200 20 189 40.1 0.212 25 192 43.5 0.226 30 195 46.8 0.240 35 198 49.9 0.252 40 201 53.3 0.265

[0134] The light intensity mentioned above is a relative measurement.

[0135] In some cases, the first photoelectric processing unit 30 can also preprocess the first optical signal to obtain a third preprocessed signal. Therefore, the data analysis unit 50 can also be used to determine the temperature data of the temperature source 60 based on the first and third preprocessed signals.

[0136] Specifically, the Brillouin frequency shift of the third preprocessed signal relative to the first preprocessed signal can be determined. Determine the ratio I of the Stokes intensity to the anti-Stokes intensity in the first preprocessed signal. S / I AS Determine the peak wavelength of thermal radiation in the first preprocessed signal. .

[0137] Subsequently, based on the signal-to-noise ratio of Brillouin frequency shift, the signal-to-noise ratio of the ratio of Stokes light intensity to anti-Stokes light intensity, and the signal-to-noise ratio of the peak wavelength of thermal radiation, the weights corresponding to the Brillouin frequency shift, the ratio of Stokes light intensity to anti-Stokes light intensity, and the peak wavelength of thermal radiation are dynamically determined.

[0138] Then, based on the Brillouin frequency shift, the ratio of Stokes intensity to anti-Stokes intensity, the peak wavelength of thermal radiation, the weight corresponding to the Brillouin frequency shift, the weight corresponding to the ratio of Stokes intensity to anti-Stokes intensity, and the weight corresponding to the peak wavelength of thermal radiation, the temperature data of the temperature source is determined.

[0139] As an example, the temperature data of temperature source 60 can be determined based on the following formula 1. Formula 1

[0140] Where T represents temperature data (in Kelvin); w1 represents the weight of the Brillouin term; w2 represents the weight of the Raman term; w3 represents the weight of the thermal radiation term; w1 + w2 + w3 = 1, and... SNR i SNR j The signal-to-noise ratio represents the parameter. , This represents the standard deviation of the measurement, where i takes values ​​of 1, 2, or 3. This represents the Brillouin frequency shift (in GHz); α and β are preset calibration parameters. This represents the ratio of Stokes intensity to anti-Stokes intensity; Represents the Boltzmann factor. denoted as Raman displacement (in Hz), h as Planck's constant, and k as Boltzmann's constant; Indicates the peak wavelength of thermal radiation; This represents Wien's displacement constant.

[0141] Therefore, by using Formula 1, the temperature of a temperature source can be determined by combining three independent physical parameters: phonon dynamics (Brillouin), molecular vibrational energy levels (Raman), and blackbody radiation (thermodynamics), thus overcoming the limitations of a single parameter. Furthermore, the weights of each parameter can dynamically change with the real-time signal-to-noise ratio, thereby improving the robustness of temperature data determination and making it suitable for temperature monitoring in extreme scenarios.

[0142] It is understood that in the above optional implementation methods, the first preprocessed signal includes the Stokes intensity and anti-Stokes intensity of the back-Raman scattered light, and the data analysis unit determines the temperature data by the ratio of the two. The characteristics of the back-Raman scattered light are closely related to the temperature. This temperature determination method based on this characteristic has high sensitivity and accuracy, thus improving the accuracy of temperature measurement.

[0143] In some optional implementations of this embodiment, the second preprocessed signal includes a wavelength shift of the backscattered Rayleigh light.

[0144] See Figure 2 , Figure 2This is a schematic diagram of the scattering spectrum in an integrated fiber optic sensor provided in an embodiment of this disclosure. The spectra of backscattered Raman light, backscattered Rayleigh light, and Brillouin scattering are shown in the figure.

[0145] The data analysis unit 50 is used to determine the strain data of the strain source 70 based on the wavelength shift.

[0146] Rayleigh scattering light is the scattered light produced when light interacts with molecules or particles in matter, without energy exchange between the photons and the light, only a change in the direction of propagation.

[0147] Wavelength shift refers to the amount of change in the wavelength of the scattered light relative to the wavelength of the incident light (e.g., a second optical signal).

[0148] Here, strain data can be calculated based on the known ratio between wavelength shift and strain; alternatively, the strain data can be calculated after correcting and compensating the wavelength shift signal.

[0149] Specifically, the wavelength shift of the backscattered Rayleigh light is closely related to the strain state of the optical fiber. By monitoring these minute wavelength changes, the strain data experienced by the optical fiber can be accurately obtained.

[0150] Wavelength shift With strain data The relationship can be represented as:

[0151] Wherein, K is the strain sensitivity (K is approximately 0.0005~0.001nm for single-mode fiber at 1550nm).

[0152] Therefore, based on the wavelength shift, the strain data of the strain source can be determined using Table 2.

[0153]

[0154] The wavelength offset mentioned above includes a measurement fluctuation of ±0.02 pm.

[0155] In some cases, the second photoelectric processing unit 40 can also preprocess the second optical signal to obtain a fourth preprocessed signal. Therefore, the data analysis unit 50 can also be used to determine the strain data of the strain source 70 based on the second and fourth preprocessed signals.

[0156] Specifically, the Raman shift, Brillouin shift, and Rayleigh scattering shift of the second preprocessed signal relative to the fourth preprocessed signal can be determined.

[0157] Subsequently, the first stress data of the stress source can be determined based on the Raman frequency shift, the second stress data of the stress source can be determined based on the Brillouin frequency shift, and the third stress data of the stress source can be determined based on the Rayleigh scattering shift.

[0158] Then, determine the mean and standard deviation of the first stress data, the second stress data, and the third stress data.

[0159] Subsequently, for each stress data point in the first, second, and third stress data sets, it is determined whether the absolute value of the difference between that stress data point and the average value is greater than a preset multiple (e.g., 3 times) of the standard deviation. If it is greater, the stress data point is classified as an abnormal stress data point; otherwise, it is classified as a normal stress data point.

[0160] Finally, the average value of the normal stress data in the first stress data, second stress data, and third stress data is determined as the final strain data of the strain source.

[0161] It is understood that in the above optional implementation methods, the second preprocessing signal is clearly defined as the wavelength shift of the backscattered Rayleigh light, and the data analysis unit determines the strain data based on this. The wavelength shift of the backscattered Rayleigh light has a definite correlation with the strain. This strain determination method based on this characteristic can accurately reflect the magnitude of the strain, thus improving the accuracy of strain measurement.

[0162] In some optional implementations of this embodiment, the first photoelectric processing unit 30 includes a first photodiode 311, a first driving board 312 of the first photodiode 311, a first voltage amplifier 313, and a first development board 314 connected in sequence.

[0163] The second optoelectronic processing unit 40 includes a second photodiode 411, a second driving board 412 for the second photodiode 411, a second voltage amplifier 413, and a second development board 414 connected in sequence.

[0164] The first photodiode 311 is used to: convert the first modulation signal into a first electrical signal; and transmit the first electrical signal to the first voltage amplifier 313 via the first driver board 312.

[0165] The first voltage amplifier 313 is used to: amplify the first electrical signal to obtain a first amplified signal; and transmit the first amplified signal to the first development board 314.

[0166] The first development board 314 is used to: extract the Stokes intensity and anti-Stokes intensity of the backscattered Raman light from the first amplified signal; and generate a first preprocessed signal based on the Stokes intensity and anti-Stokes intensity.

[0167] The second photodiode 411 is used to: convert the second modulation signal into a second electrical signal; and transmit the second electrical signal to the second voltage amplifier 413 via the second driver board 412.

[0168] The second voltage amplifier 413 is used to: amplify the second electrical signal to obtain a second amplified signal; and transmit the second amplified signal to the second development board 414.

[0169] The second development board 414 is used to: extract the wavelength shift of the backscattered Rayleigh light from the second amplified signal; and generate a second preprocessed signal based on the wavelength shift.

[0170] The first photodiode 311 and the second photodiode 411 are semiconductor devices that can convert optical signals into electrical signals, and their working principle is based on the photovoltaic effect. Here, the first photodiode 311 converts the first modulation signal (optical signal) into the first electrical signal, and the second photodiode 411 converts the second modulation signal (optical signal) into the second electrical signal, and are the key components for optical signal to electrical signal conversion.

[0171] The first driver board 312 and the second driver board 412 are circuit boards that provide stable operating voltage and current for the photodiodes. They can provide appropriate voltages to the corresponding photodiodes to ensure their normal operation, and simultaneously transmit the electrical signals output by the photodiodes stably to the voltage amplifier.

[0172] The first voltage amplifier 313 and the second voltage amplifier 413 are electronic devices that amplify weak voltage signals to the required amplitude. They amplify the weak electrical signals output by the corresponding photodiodes for subsequent signal processing and analysis on the development board.

[0173] The first development board 314 and the second development board 414 are circuit boards that integrate microprocessors, input / output interfaces, etc., and can be used for data acquisition, processing, and control. The first development board 314 extracts the characteristic parameters of the backscattered Raman light from the amplified first electrical signal and generates a first preprocessed signal, and the second development board 414 extracts the characteristic parameters of the backscattered Rayleigh light from the amplified second electrical signal and generates a second preprocessed signal.

[0174] The first electrical signal is the electrical signal obtained by converting the first modulation signal into a first electrical signal by the first photodiode 311, which carries temperature-related information.

[0175] The second electrical signal is the electrical signal obtained by converting the second modulation signal into a second signal by the second photodiode 411, which carries strain-related information.

[0176] The first amplified signal is the signal obtained by amplifying the first electrical signal by the first voltage amplifier 313.

[0177] The second amplified signal is the signal obtained after the second voltage amplifier 413 amplifies the second electrical signal.

[0178] It is understandable that in the above optional implementation methods, photoelectric conversion is achieved through photodiodes, weak signals are amplified by voltage amplifiers, and feature parameters are extracted by the development board and preprocessed signals are generated. Each step processes the signal in a targeted manner, reducing signal loss and noise interference, thereby improving the quality and efficiency of signal processing and providing reliable input signals for the data analysis unit.

[0179] In some application scenarios of the above-mentioned optional implementation methods, the first photodiode 311, the first driving board 312, the second photodiode 411, and the second driving board 412 are disposed in a dark box. Figure 4 In the dark box 315, the first photodiode 311 and the first driving board 312 are disposed in the dark box 315, and the second photodiode 411 and the second driving board 412 are disposed in the dark box 415.

[0180] A dark box is a light-shielding enclosure that effectively blocks external light from entering. It provides a dark or low-light environment for photodiodes and driver boards, preventing ambient light from interfering with the photodiode's optical signal detection.

[0181] Here, the photodiode and driver board can be fixed inside the dark box using screws or a bracket; alternatively, they can be glued to the appropriate position on the inner wall of the dark box.

[0182] The interior of the dark chamber uses the same black adhesive coating as the inside of blackout curtains. This coating, made of a black adhesive material (such as acrylate, polyurethane, or other polymers), is typically applied in multiple layers to enhance its light-blocking effect. This black adhesive coating is low-cost and provides strong light-blocking performance. It can absorb over 99% of incident light, creating a near-light-free environment inside the dark chamber, which is crucial for maintaining the stability of the photodiode detection signal. The structure of the dark chamber is carefully designed to accommodate the size of the photodiode and provide the necessary installation and mounting space, while maintaining excellent sealing performance to prevent any external light from penetrating. By using the dark chamber, experimental errors caused by fluctuations in ambient light can be significantly reduced under different environmental conditions, thereby improving the accuracy and reliability of measurement data.

[0183] It is understandable that in the above application scenario, since the first photodiode, the second photodiode and their driving board are placed in a dark box, the dark box can effectively block the entry of external ambient light, avoid the interference of ambient light on the photodiode detection light signal, reduce the noise in the electrical signal, and make the photoelectric conversion process more stable and accurate, thereby improving the quality of subsequent signal processing and measurement accuracy.

[0184] In some application scenarios of the above-mentioned optional implementations, the first voltage amplifier 313 and the second voltage amplifier 413 have an input impedance of 5 megohms and an output impedance of 100 ohms, respectively.

[0185] Input impedance refers to the impedance presented by a circuit or device to a signal source at its input terminal. Here, a high input impedance of 5 megohms can reduce the shunting of the voltage amplifier to the output signal of the preamplifier, ensuring that more signal energy enters the amplifier and reducing signal loss.

[0186] Output impedance refers to the impedance presented by a circuit or device at its output terminal. Here, a low output impedance of 100 ohms enhances the load-driving capability of the voltage amplifier, ensuring stable transmission of the amplified signal to the subsequent development board and reducing signal distortion during transmission.

[0187] Understandably, in the above application scenario, the first and second voltage amplifiers have an input impedance of 5 megohms and an output impedance of 100 ohms. The high input impedance reduces the shunting of the preceding signal, ensuring more signal enters the amplifier; the low output impedance enhances the load-carrying capacity, enabling stable signal transmission to the subsequent development board. This reduces signal loss and distortion during transmission, improves the quality of signal amplification, and provides a more reliable signal for the subsequent development board to extract characteristic parameters, thereby improving the sensor's measurement accuracy. The aforementioned voltage amplifiers effectively amplify the weak voltage signals output by the photodiode, typically only a few microvolts to a few millivolts, to a level of 0-5 volts. This process significantly improves the signal-to-noise ratio, ensuring signal stability and reliability during transmission. The amplified voltage signal is then transmitted to the development board, enabling it to accurately read and process these signals. This design not only optimizes signal transmission efficiency but also provides a solid foundation for subsequent data acquisition and analysis, thereby improving the performance and accuracy of the entire sensor system when measuring temperature and strain.

[0188] In some application scenarios of the above-mentioned optional implementation methods, the first photodiode 311, the first driving board 312, the first voltage amplifier 313, the second photodiode 411, the second driving board 412, and the second voltage amplifier 413 are disposed in a constant temperature chamber.

[0189] A constant temperature chamber is a device that maintains a constant internal temperature by using methods such as heating and cooling to control the internal temperature within a preset range. Here, a stable temperature environment is provided for photodiodes, driver boards, and voltage amplifiers, preventing changes in ambient temperature from affecting their performance.

[0190] It is understandable that in the above application scenarios, because the photodiode, driver board and voltage amplifier are placed in a constant temperature chamber, the constant temperature chamber can maintain a constant temperature environment, avoiding the impact of ambient temperature changes on the performance of these electronic devices, such as preventing device parameter drift caused by temperature changes, ensuring that they work under stable conditions, thereby improving the stability of signal processing and measurement accuracy.

[0191] In some optional implementations of this embodiment, the light source emitting unit 10 is used to emit a light source with a wavelength of 1550 nanometers in a preset constant temperature environment.

[0192] A preset constant temperature environment refers to an environment with a pre-defined constant temperature. This provides a stable operating temperature for the light source emitting unit, reducing the impact of ambient temperature changes on the wavelength stability of the light source. To achieve constant temperature operation of the light source, the emitting unit can be installed in a constant temperature module equipped with a temperature sensor and heating / cooling device, maintaining a constant temperature through feedback control; alternatively, a thermoelectric cooler can be integrated with the light source to adjust its temperature in real time and keep it stable.

[0193] It is understandable that in the above-mentioned optional implementation methods, since the light source emitting unit operates in a preset constant temperature environment, the impact of ambient temperature changes on the light source wavelength is reduced, ensuring the stability of the light source wavelength; at the same time, the 1550 nm wavelength light source has low transmission loss in single-mode fiber and is suitable for temperature and strain measurement. The stable light source wavelength makes the beam splitting coupling, signal modulation, and detection processes more stable, reducing measurement errors caused by light source fluctuations, thereby improving the consistency and accuracy of sensor measurements.

[0194] In some cases, the distance between the temperature source and / or strain source and the data analysis unit is greater than or equal to 10 kilometers.

[0195] It should be noted that, where there is no conflict, the technical features described in different alternative implementations can be included in the same embodiment. For the sake of brevity, they will not be elaborated here.

[0196] The integrated fiber optic sensor provided in this disclosure includes a light source emitting unit, a beam splitting coupling unit, a first photoelectric processing unit, a second photoelectric processing unit, and a data analysis unit. The beam splitting coupling unit is connected to the light source emitting unit, the first photoelectric processing unit, and the second photoelectric processing unit via single-mode optical fibers. The data analysis unit is electrically connected to both the first and second photoelectric processing units. The beam splitting coupling unit is used to: split the light emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to a temperature source; and transmit a first modulated signal obtained by modulating the first optical signal with the temperature source to a first... The system includes a photoelectric processing unit; a first photoelectric processing unit transmits a second optical signal to a strain source, and a second modulated signal obtained by modulating the second optical signal by the strain source is transmitted to a second photoelectric processing unit. The first photoelectric processing unit preprocesses the first modulated signal to obtain a first preprocessed signal and transmits the first preprocessed signal to a data analysis unit. The second photoelectric processing unit preprocesses the second modulated signal to obtain a second preprocessed signal and transmits the second preprocessed signal to the data analysis unit. The data analysis unit determines the temperature data of the temperature source based on the first preprocessed signal and determines the strain data of the strain source based on the second preprocessed signal. Therefore, the light emitted by the same light source emitting unit can be split into two optical signals, transmitted via single-mode fiber, and modulated by the temperature source and strain source, then preprocessed separately by independent photoelectric processing units. Finally, the data analysis unit determines the temperature data of the temperature source and the strain data of the strain source, thereby improving the accuracy of the fiber optic sensor in detecting temperature and strain.

[0197] The following describes the embodiments of this disclosure by way of example. However, it should be noted that the following content is only used to understand the technical solutions of the embodiments of this disclosure and does not constitute a limitation on the protection scope of the embodiments of this disclosure.

[0198] Since its emergence in the 1970s, fiber optic sensing technology has gradually demonstrated significant application value in fields such as communications, medicine, aerospace, and structural health monitoring due to its unique advantages, such as resistance to electromagnetic interference, corrosion resistance, and ability to operate in harsh environments. Distributed fiber optic sensors, as an important branch of fiber optic sensing technology, have become a research and application hotspot because they can perform continuous measurements along the entire length of the fiber, offering continuity and wide coverage that traditional point sensors cannot match.

[0199] Distributed fiber optic sensors face numerous challenges in signal analysis and processing. Scattered light signals are typically weak and susceptible to noise, requiring complex algorithms to extract useful information. Existing signal processing techniques often suffer from high computational demands, poor real-time performance, and insufficient accuracy, all of which affect the sensor's performance in practical applications.

[0200] To overcome these challenges, technologies capable of accurately monitoring and analyzing the characteristics of scattered light are needed. This includes improving the detection sensitivity of scattered light signals, optimizing signal processing algorithms, and reducing the influence of environmental factors. Furthermore, to verify the stability and reliability of the sensor, long-term monitoring of scattered light characteristics and extensive testing under different environments and conditions are required to ensure that the sensor can provide accurate data in practical applications.

[0201] This scheme employs time-division multiplexing technology, allowing the two scattered light signals to be detected within different time windows, thus avoiding interference between signals and improving the accuracy and reliability of the measurement. Extremely weak scattered light signals are detected using a highly sensitive photodiode.

[0202] Furthermore, it can be used with a dedicated voltage amplifier (including the first voltage amplifier and the second voltage amplifier mentioned above) to amplify the voltage signal converted by the photodiode (including the first photodiode and the second photodiode) to a level suitable for the Arduino development board (including the first development board and the second development board mentioned above) to receive. The low-noise design of the amplifier ensures the clarity and stability of the signal.

[0203] This solution employs an integrated design, combining photodiodes, driver boards, voltage amplifiers, and development boards into a compact measurement system. The modular design facilitates sensor maintenance and upgrades, enhancing system flexibility and scalability.

[0204] To adapt to different environmental conditions, this solution optimizes the sensor for environmental adaptability, including anti-corrosion treatment of optical fibers, design of temperature compensation circuit, and adoption of anti-vibration measures.

[0205] The anti-corrosion treatment of optical fibers mainly focuses on optimizing their outer protective structure, with the core objective of isolating them from external corrosive media (such as moisture, chemical reagents, salt spray, etc.). Since this experiment involves cutting optical fibers, multiple protective coatings are applied to the surface of the bare fiber (made of quartz glass, which is susceptible to chemical corrosion). The inner layer is a buffer layer (such as silicone rubber) to absorb stress, and the outer layer is a corrosion-resistant coating (such as polyimide) to enhance resistance to chemical environments.

[0206] Temperature compensation circuits and anti-vibration measures are used in the strain branch and temperature branch, respectively, so that the influence of temperature can be eliminated when measuring strain, and the influence of strain can be eliminated when measuring temperature.

[0207] The core of the temperature compensation circuit is to eliminate the impact of temperature changes on the sensor's measurement accuracy (mainly for strain measurement branches, as fiber optic temperatures inevitably change due to friction and other factors during strain measurement experiments). The development board compares the sensor signal with a reference temperature signal and corrects the signal in real time according to a preset temperature-error model (such as a linear correction formula). For example, if a 1-degree Celsius increase in temperature causes a 0.02-volt shift in the measured value, the circuit automatically subtracts this shift and outputs the compensated, accurate signal.

[0208] The purpose of anti-vibration measures is to reduce the interference of mechanical vibration on fiber optic sensors (mainly for branches that measure temperature). For critical nodes (such as the connection between the fiber and the splitter or photodiode), rigid brackets (such as metal clamps) are used to fix them to ensure that the connection points remain in place during vibration and to prevent optical signal attenuation or interruption due to loosening.

[0209] Furthermore, through these measures, the sensor is able to maintain stable measurement performance in harsh environments.

[0210] This solution utilizes a highly efficient data processing algorithm to rapidly analyze the acquired scattered light signals and calculate accurate temperature and strain values. The algorithm includes filtering, noise reduction, and data fusion steps, effectively improving the signal-to-noise ratio and measurement accuracy. This solution supports real-time monitoring and, through a wireless communication module, enables remote data transmission and control, facilitating data analysis and equipment management from a remote center. This solution has undergone rigorous stability and reliability testing, including long-term continuous operation testing, temperature cycling testing, and mechanical vibration testing, ensuring the stability and reliability of the sensor in practical applications. Through optimized design and manufacturing processes, the sensor maintains high performance while reducing manufacturing costs, making the product more competitive in the market. The sensor is suitable for various industries, including but not limited to petrochemicals, power systems, transportation, and civil engineering. Its powerful functions and flexible design provide new solutions for monitoring in these fields. The sensor has a self-calibration function, automatically detecting and correcting system deviations to ensure measurement accuracy during long-term operation. Through a built-in standard light source and reference fiber, the sensor can self-calibrate at preset time intervals or according to user instructions, reducing errors caused by system aging or environmental changes.

[0211] The reference fiber in this scheme is the same type of fiber used in the sensing fiber for measuring temperature and strain, but it is not in contact with external temperature or strain sources and exists in a relatively stable environment unaffected by external physical quantities. Its function is to provide a stable optical signal reference standard to reflect the inherent characteristics of the system itself, such as the inherent loss of the fiber, the splitting characteristics of the beam splitter, and the background response of the photodiode. By comparing the optical signals from the reference fiber and the sensing fiber, changes in the optical signal caused by external physical quantities can be separated, eliminating interference from system-specific factors on the measurement results, achieving calibration of the measurement data, and ensuring the accuracy and reliability of the measurement results.

[0212] The sensor's software system is highly configurable, allowing users to adjust parameter settings such as measurement range, resolution, and sampling frequency according to actual measurement needs. The software interface supports graphical operation, facilitating quick learning and complex configuration. The sensor incorporates an anti-electromagnetic interference design, ensuring stable operation even in strong electromagnetic environments.

[0213] Due to the inherent electromagnetic shielding properties of optical fibers, combined with a dedicated anti-interference circuit design, the sensor's anti-interference capability is further enhanced. The sensor in this solution is designed for miniaturization, reducing size and weight for easy portability and installation. Its portability allows for application in rapid on-site detection and mobile monitoring scenarios, broadening its application scope. The sensor integrates a fault diagnosis and early warning system, enabling real-time monitoring of system status and immediate warning signals upon detecting potential faults or anomalies. This system helps users promptly identify problems and take corrective measures to prevent major accidents. The sensor has a large-capacity data storage function, capable of storing long-term measurement data for historical review and analysis. It supports cloud data synchronization, allowing users to access historical data from any location for trend analysis and decision support. The sensor in this solution can be fused with other types of sensors (such as pressure sensors and humidity sensors) to form a multi-parameter monitoring system. Through data fusion technology, the status of target objects can be monitored more comprehensively, improving the overall performance of the monitoring system. The sensor employs a low-power design, suitable for long-term unattended monitoring applications, reducing energy consumption and maintenance costs. Optimized circuit design and the selection of energy-saving components achieve high performance while reducing power consumption. The sensor has a simple structure, is easy to install, and can be deployed quickly. Maintenance is simple, reducing maintenance time and costs and improving the overall operating efficiency of the system.

[0214] like Figure 4As shown, the distributed fiber optic sensor of the present invention includes a light source emitting unit 10 (for emitting light), a beam splitting and coupling unit 20 (including a first beam splitter 211, a second beam splitter 212, a third beam splitter 213, a first coupler 221, a second coupler 222, a third coupler 223, a fourth coupler 224, a fifth coupler 225, a sixth coupler 226, a seventh coupler 227, an eighth coupler 228, and a ninth coupler 229), a fiber optic sensing unit (single-mode fiber), a photoelectric detection unit (including a first photodiode 311, a first driver board 312, a second photodiode 411, and a second driver board 412), a voltage amplifier (including a first voltage amplifier 313 and a second voltage amplifier 413), an Arduino UNO R3 data board (including a first development board 314 and a second development board 414), and a data analysis unit 50 (computer).

[0215] The light source emitting unit 10 uses a distributed feedback laser (DFB Laser) as the light source to emit a stable optical signal with a wavelength of 1550 nanometers. The light source emitting unit 10 also includes a temperature controller to ensure that the laser maintains a constant temperature during operation, thereby ensuring the stability of the optical signal.

[0216] The first coupler 221 is responsible for efficiently coupling the optical signal emitted by the light source emitting unit into the single-mode optical fiber. To reduce coupling loss, the first coupler 221 uses an optical fiber adapter and a coupling lens to ensure the transmission efficiency of the optical signal.

[0217] The fiber optic sensing unit includes a specially designed sensing fiber. When the optical signal propagates in the fiber, changes in temperature and strain will generate backscattered Raman light and backscattered Rayleigh light. The two ends of the sensing fiber are connected to the light source emitting unit 10 and the photoelectric detection unit, respectively.

[0218] The photodetector unit consists of a photodiode and a preamplifier (PD (Photodiode Driver) board), responsible for converting scattered light signals into electrical signals. The photodiode can accept light signals with wavelengths of 800-1700 nanometers, with a saturation power of 7 milliwatts and a photosensitive surface of 500 micrometers. This is based on its high responsivity and low dark current characteristics, thereby reducing signal conversion errors.

[0219] A voltage amplifier is used to amplify the weak electrical signal output by a photodiode. After the signal exits the voltage amplifier, it can be limited to the 0-5 volt range by a bandpass filter. The filter is designed to suppress noise and improve signal quality.

[0220] The Arduino UNO R3 data board converts analog signals into digital signals and transmits them to a computer via a USB (Universal Serial Bus) interface. The data acquisition card features 16-bit resolution and a sampling rate of up to 100 kHz, ensuring high-precision data acquisition.

[0221] The computer can run analysis software responsible for receiving, processing, and analyzing the digital signals transmitted by the data acquisition card. The software includes the following modules:

[0222] Data preprocessing module: performs digital filtering, noise reduction, and normalization on the acquired signals.

[0223] Scattered light characteristics analysis module: Calculates temperature and strain values ​​based on the wavelength and intensity changes of backscattered Raman and backscattered Rayleigh light, respectively.

[0224] Real-time monitoring and display module: Displays measurement results in real time in graphical and tabular form, and provides historical data query function.

[0225] To improve the stability and reliability of the system, the following measures were taken:

[0226] Step S1: Light source stability control. By monitoring the output power and wavelength of the light source in real time, a closed-loop control system is used to adjust the light source parameters to ensure the stability of the output optical signal.

[0227] Step S2: Environmental Adaptability Design. The photoelectric detection unit and signal amplification unit are placed in a sealed, temperature-controlled chamber to reduce the impact of changes in ambient temperature and humidity on the measurement results.

[0228] Step S3: System Calibration. Periodically calibrate the system using a standard light source and standard samples with known temperature / strain to correct for system deviations.

[0229] Therefore, this solution enables simultaneous measurement of both temperature and strain, improving measurement efficiency and data correlation. The sensing fiber optic cable can reach lengths of tens of kilometers, achieving continuous monitoring over a large area. Through precise photoelectric conversion and signal processing technology, high-precision and high-stability measurements are achieved. Combined with computer analysis software, real-time data monitoring and post-processing are realized, facilitating user operation and analysis. It can achieve long-distance, high-precision, real-time monitoring of temperature and strain. The system has been tested in multiple application scenarios, demonstrating excellent performance and reliability.

[0230] In this scheme, the light source signal is split into two paths after it is emitted: one path is used to measure temperature, and the other path is used to measure strain. Each of the two paths is further split into two paths: one path is used to detect the sensor signal, and the other path is used to process the sensor signal.

[0231] Figure 3 This diagram illustrates the connection of a photodiode, driver board, voltage amplifier, and development board in an integrated fiber optic sensor according to an embodiment of this disclosure. A first photodiode 311 is connected to a first driver board 312 and is provided with a stable 5-volt voltage by a first development board (e.g., an Arduino UNO R3 development board) 314. This allows the first driver board 312 to collect the photoelectric signal converted by the first photodiode 311. The signal is then connected to a first voltage amplifier 313 via the SIGN interface of the first driver board 312. After amplification by the voltage amplifier, the photoelectric signal is finally sent to the first development board 314 via the OUT interface. The final experimental result is obtained after software processing on a computer.

[0232] Furthermore, the second photodiode 411, the second driver board 412 of the second photodiode 411, the second voltage amplifier 413, and the second development board 414 can be connected in the same way as the first photodiode 311, the first driver board 312 of the first photodiode 311, the first voltage amplifier 313, and the first development board 314, which will not be described in detail here.

[0233] Figure 4 In actual experiments, the couplers play two main roles. First, they transmit optical signals. Since the devices are not integrated, couplers are needed to transfer optical signals from one device to another. Second, they combine the feedback light generated by the sensing fiber (i.e., single-mode fiber) into a single path and send it back to the other path of the beam splitter.

[0234] In optical sensing experimental systems, beam splitters need to precisely distribute optical signals to two independent optical paths at an approximately 1:1 optical power ratio to achieve the requirements of split-path detection. If the two beam splitters are directly connected via couplers, it will disrupt the stability and independence of optical power distribution, causing fluctuations in the received optical signal intensity, interfering with the accuracy of temperature and strain sensing, and also leading to cross-influence between different experimental circuits, thus compromising the independence of detection. Therefore, a "fiber + dual coupler" connection architecture is adopted, with the two couplers working together to construct an optical signal buffering and modulation mechanism.

[0235] Among them, the fifth coupler 225 and the eighth coupler 228 can be connected to the output of the preceding optical splitter to perform preliminary adaptation and power pre-allocation of the optical signal, and to sort out the optical signal transmission path in preparation for subsequent transmission.

[0236] The sixth coupler 226 and the ninth coupler 229 can connect to the input of the subsequent beam splitter to further precisely control the optical power, ensure the stability and reasonable distribution of the optical signal power input to the subsequent beam splitter, strictly maintain the independence of the optical signals of the two experimental lines (temperature and strain detection), avoid interference between lines, ensure the accuracy and stability of temperature and strain sensing detection, and provide optical link support for the reliable operation of the system.

[0237] The beam splitters used in the experiment all had one input port and two output ports.

[0238] The input port of the first beam splitter 211 is used to receive the initial optical signal emitted by the system's main light source, serving as the starting point for optical signal distribution. The output port is used to stably distribute the input optical signal into two independent optical signals according to a preset ratio (approximately 1:1). Its function is to perform the "first-level distribution" of the system's optical signals. Based on experimental requirements, it splits the single-source optical signal into two paths, which are then sent to the "temperature sensing experimental branch" and the "strain sensing experimental branch" respectively. It is the fundamental optical distribution unit for constructing a parallel temperature and strain detection architecture, determining the initial optical signal supply to the two detection branches.

[0239] The second beam splitter 212 and the third beam splitter 213 (functionally symmetrical, distinguishing temperature / strain branches as needed). The input ports are used to receive one optical signal distributed by the first beam splitter 211 (one corresponding to the second beam splitter 212, and the other to the third beam splitter 213), serving as the input source for branch optical signal processing. The output ports are used for: one output connecting to the "sensing fiber" (connected to the temperature / strain sensing module for interaction with external signals); and the other output connecting to the "signal receiving and processing line" (connected to the photoelectric detection, signal amplification, and data acquisition unit). Function: Performing "two-level distribution" and "functional splitting" of the branch optical signals. On the one hand, the branch optical signal transmitted from the first beam splitter 211 is further split into a "sensor interaction path" and a "signal detection path". The "sensor interaction path" couples the optical signal with the external temperature / strain signal through the sensing fiber to complete the optical signal modulation. The "signal detection path" guides the modulated optical signal to the detection unit to realize the sensing closed loop of the optical signal. It is the core unit for building the single branch (temperature or strain) "optical interaction-optical detection" function and ensures the independent operation of single physical quantity (temperature / strain) sensing and detection.

[0240] When the sensing fiber is affected by an external signal and generates backscattered light, it will be transmitted to another branch through a beam splitter. However, the optical signal is transmitted inside the fiber rather than being exposed on the outside. In order to allow the optical signal to directly illuminate the photosensitive surface of the photodiode, one end of the fiber needs to be cut using a fiber optic trimming tool.

[0241] In this design, the optical fiber itself acts as a sensor to receive external physical signals. These signals are then transmitted through the fiber optic cable to the cut surface, and finally to a photodiode, which converts the optical signal into an electrical signal. A driver board is connected below the photodiode to provide a stable voltage. The converted voltage signal is then passed to a voltage amplifier, which is connected to the A2 receiver of an Arduino UNO R3 to receive the amplified voltage signal. The Arduino UNO R3's port 5 provides 5 volts to the PD driver board, while the voltage amplifier is connected to a 13 volt power supply and sends the amplified voltage signal to the Arduino UNO R3, which then transmits it to a computer via a USB interface.

[0242] In practice, a 1550-nanometer wavelength laser beam is emitted into an optical fiber. As the laser propagates through the fiber, it interacts with molecular or structural defects within the fiber, generating backscattered Raman and backscattered Rayleigh light. This scattered light carries information about temperature and strain, which is collected and analyzed by a highly sensitive detection system.

[0243] The intensity of backscattered Raman light is closely related to temperature changes. By detecting the ratio of Stokes and anti-Stokes components in its spectrum, the temperature distribution at various points along the optical fiber can be accurately calculated.

[0244] This sensor utilizes a high-resolution spectral analyzer and signal processing algorithms to separate temperature and strain information from mixed scattered light signals, achieving high-precision measurement. This integrated measurement method not only improves measurement efficiency but also reduces cross-interference in data processing, ensuring the accuracy and stability of the measurement results. Therefore, the integrated distributed fiber optic sensor of this invention has broad application prospects in structural health monitoring, smart materials, aerospace, and other fields.

[0245] It should be noted that, in addition to the contents described above, this embodiment may also include the technical features described in the above embodiments, thereby achieving the technical effects of the document processing method shown above. For details, please refer to the above description. For the sake of brevity, it will not be elaborated here.

[0246] Based on the embodiments disclosed herein, this method can be used to simultaneously measure temperature and strain. By employing a beam splitter to achieve dual-path sensing, it improves measurement efficiency and accuracy, making it applicable to multiple fields such as communications, medicine, and military. Utilizing the principles of Raman and Rayleigh scattering, this scheme provides a technical means for the precise measurement of physical quantities. It employs a distributed fiber optic sensor design, splitting the optical path into two independent paths via a beam splitter. Each path senses external physical interferences, such as different temperature and strain conditions. This dual-path design allows for the simultaneous and independent measurement of temperature and strain, significantly improving measurement efficiency and accuracy. The signals returned from the sensing fiber, after analysis, can provide detailed temperature and strain data, offering a new technical means for the precise measurement of various physical quantities.

[0247] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “” used herein may also indicate the inclusion of the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated, unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0248] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A composite fiber optic sensor, characterized in that, The integrated fiber optic sensor includes a light source emitting unit, a beam splitting and coupling unit, a first photoelectric processing unit, a second photoelectric processing unit, and a data analysis unit. The beam splitting and coupling unit is connected to the light source emitting unit, the first photoelectric processing unit, and the second photoelectric processing unit via single-mode optical fibers. The data analysis unit is electrically connected to both the first photoelectric processing unit and the second photoelectric processing unit. The beam splitting coupling unit is used to: split the light source emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to a temperature source, and transmit a first modulation signal obtained by the temperature source modulating the first optical signal to the first photoelectric processing unit; transmit the second optical signal to a strain source, and transmit a second modulation signal obtained by the strain source modulating the second optical signal to the second photoelectric processing unit; The first photoelectric processing unit is configured to: preprocess the first modulation signal to obtain a first preprocessed signal; and transmit the first preprocessed signal to the data analysis unit. The second photoelectric processing unit is used to: preprocess the second modulation signal to obtain a second preprocessed signal; and transmit the second preprocessed signal to the data analysis unit. The data analysis unit is used to: determine the temperature data of the temperature source based on the first preprocessed signal; and determine the strain data of the strain source based on the second preprocessed signal. The first photoelectric processing unit is further configured to: preprocess the first optical signal to obtain a third preprocessed signal; The data analysis unit is specifically used for: determining the Brillouin frequency shift of the third preprocessed signal relative to the first preprocessed signal; determining the ratio of Stokes light intensity to anti-Stokes light intensity in the first preprocessed signal; determining the peak wavelength of thermal radiation in the first preprocessed signal; dynamically determining the weights corresponding to the Brillouin frequency shift, the ratio of Stokes light intensity to anti-Stokes light intensity, and the peak wavelength of thermal radiation based on the signal-to-noise ratio of the Brillouin frequency shift, the signal-to-noise ratio of the ratio of Stokes light intensity to anti-Stokes light intensity, and the peak wavelength of thermal radiation; and determining the temperature data of the temperature source based on the weights corresponding to the Brillouin frequency shift, the ratio of Stokes light intensity to anti-Stokes light intensity, the peak wavelength of thermal radiation, the weights corresponding to the Brillouin frequency shift, the ratio of Stokes light intensity to anti-Stokes light intensity, and the peak wavelength of thermal radiation.

2. The integrated fiber optic sensor according to claim 1, characterized in that, The beam splitting coupling unit includes a first subunit, a second subunit, and a third subunit; The first subunit is connected to the light source emitting unit and the second subunit, respectively; The second subunit is also connected to the temperature source and the first photoelectric processing unit; The third subunit is also connected to the strain source and the second photoelectric processing unit; The first subunit is configured to: split the light source emitted by the light source emitting unit into a first optical signal and a second optical signal; transmit the first optical signal to the second subunit; and transmit the second optical signal to the third subunit. The second subunit is used to: transmit the first optical signal to the temperature source, and transmit the first modulated signal obtained by modulating the first optical signal by the temperature source to the first photoelectric processing unit; The third subunit is used to: transmit the second optical signal to the strain source, and transmit the second modulated signal obtained by the strain source modulating the second optical signal to the second photoelectric processing unit.

3. The integrated fiber optic sensor according to claim 2, characterized in that: The first subunit includes a first beam splitter, a first coupler, a second coupler, and a third coupler; The second subunit includes a second beam splitter, a fourth coupler, a fifth coupler, and a sixth coupler; The third subunit includes a third beam splitter, a seventh coupler, an eighth coupler, and a ninth coupler; The first end of the first beam splitter is connected to the light source emitting unit through the first coupler, the second end of the first beam splitter is connected to the fourth coupler through the second coupler, and the third end of the first beam splitter is connected to the seventh coupler through the third coupler. The first end of the second beam splitter is connected to the fourth coupler, the second end of the second beam splitter is connected to the temperature source through the fifth coupler, and the third end of the second beam splitter is connected to the first photoelectric processing unit through the sixth coupler. The first end of the third beam splitter is connected to the seventh coupler, the second end of the third beam splitter is connected to the strain source through the eighth coupler, and the third end of the third beam splitter is connected to the second photoelectric processing unit through the ninth coupler.

4. The integrated fiber optic sensor according to claim 1, characterized in that, The first preprocessed signal includes the Stokes intensity and anti-Stokes intensity of the backscattered Raman light; and The data analysis unit is used for: Determine the ratio of the Stokes light intensity to the anti-Stokes light intensity; The temperature data of the temperature source is determined based on the ratio.

5. The integrated fiber optic sensor according to claim 1, characterized in that, The second preprocessed signal includes the wavelength shift of the backscattered Rayleigh light; and The data analysis unit is used for: Based on the wavelength shift, the strain data of the strain source is determined.

6. The integrated fiber optic sensor according to claim 1, characterized in that: The first optoelectronic processing unit includes a first photodiode, a first driver board for the first photodiode, a first voltage amplifier, and a first development board connected in sequence. The second optoelectronic processing unit includes a second photodiode, a second driver board for the second photodiode, a second voltage amplifier, and a second development board connected in sequence. The first photodiode is used to: convert the first modulation signal into a first electrical signal; and transmit the first electrical signal to the first voltage amplifier via the first driver board. The first voltage amplifier is used to: amplify the first electrical signal to obtain a first amplified signal; and transmit the first amplified signal to the first development board. The first development board is used to: extract the Stokes intensity and anti-Stokes intensity of the backscattered Raman light from the first amplified signal; and generate a first preprocessed signal based on the Stokes intensity and the anti-Stokes intensity. The second photodiode is used to: convert the second modulation signal into a second electrical signal; and transmit the second electrical signal to the second voltage amplifier via the second driver board. The second voltage amplifier is used to: amplify the second electrical signal to obtain a second amplified signal; and transmit the second amplified signal to the second development board. The second development board is used to: extract the wavelength shift of the backscattered Rayleigh light from the second amplified signal; A second preprocessed signal is generated based on the wavelength shift.

7. The integrated fiber optic sensor according to claim 6, characterized in that, The first photodiode, the first driving board, the second photodiode, and the second driving board are disposed in a dark box.

8. The integrated fiber optic sensor according to claim 6, characterized in that, The first photodiode, the first driver board, the first voltage amplifier, the second photodiode, the second driver board, and the second voltage amplifier are disposed in a constant temperature chamber.

9. The integrated fiber optic sensor according to claim 6, characterized in that, The first voltage amplifier and the second voltage amplifier have an input impedance of 5 megohms and an output impedance of 100 ohms, respectively.

10. The integrated fiber optic sensor according to any one of claims 1-9, characterized in that, The light source emitting unit is used to emit a light source with a wavelength of 1550 nanometers in a preset constant temperature environment.

Images