CN117686009B - Optical fiber double-FP composite sensing monitoring equipment - Google Patents
Optical fiber double-FP composite sensing monitoring equipment Download PDFInfo
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- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35306—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement
- G01D5/35309—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer
- G01D5/35312—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using an interferometer arrangement using multiple waves interferometer using a Fabry Perot
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
- G01D5/3538—Optical fibre sensor using a particular arrangement of the optical fibre itself using a particular type of fiber, e.g. fibre with several cores, PANDA fiber, fiber with an elliptic core or the like
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- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
- G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
- G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
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Abstract
The invention provides optical fiber double-FP composite sensing monitoring equipment, and belongs to the technical field of optical fiber composite sensing detection; the optical circulator module comprises three ports which are communicated in one direction; the output end of the optical path module is in optical path connection with the first port of the optical circulator module and is used for generating a broadband optical signal; the optical fiber double-FP composite sensor is in optical path connection with the second port of the optical circulator module and is used for receiving the broadband optical signal and sending the reflected optical signal back to the second port of the optical circulator module; the spectrometer module is connected with a third port optical path of the optical circulator module and is used for receiving the reflected light signal, carrying out spectrum acquisition and outputting spectrum information; the signal processing module is respectively connected with the light path module and the spectrometer module in a signal way and is used for providing power supply voltage for the light path module or demodulating the spectral information output by the spectrometer module; the touch display module is in communication connection with the signal processing module and is used for displaying and outputting cavity length demodulation information or touch input.
Description
Technical Field
The invention relates to the technical field of optical fiber composite sensing detection, in particular to optical fiber double-FP composite sensing monitoring equipment.
Background
The optical fiber FP sensor is used as a wavelength and phase modulation type optical fiber sensor, has the advantages of electromagnetic interference resistance, high temperature resistance, corrosion resistance, strong multiplexing capability, high pressure signal sensitivity, portability, flexibility and the like, and is widely applied to monitoring of various physical quantities such as temperature, strain, displacement and the like in the fields of aerospace, civil engineering, petrochemical industry and the like. With the development and application of optical fiber sensing and demodulation technologies, problems are gradually derived, and the problems are specifically expressed: 1. the existing fiber bragg grating sensor is complex in structure; 2. the existing demodulation system is large in size, most of demodulation systems are fiber bragg grating demodulators, and devices for demodulating by adopting optical fibers FP are fewer; 3. the existing optical fiber FP demodulation algorithm has low precision and is difficult to meet the detection requirement of high precision; 4. the demodulation result of the optical fiber sensor lacks a more visual man-machine interaction function and a history retrieval function.
The above drawbacks limit the application scenarios of the optical fiber temperature/pressure detection system, so it is very necessary to provide an optical fiber dual FP temperature/pressure composite sensing and monitoring device.
Disclosure of Invention
In view of the above, the invention provides an optical fiber double-FP composite sensing monitoring device which is suitable for temperature and pressure composite sampling occasions, is more sensitive to pressure signals and has a more compact structure.
The technical scheme of the invention is realized as follows: the invention provides optical fiber double-FP composite sensing monitoring equipment which comprises an optical fiber double-FP composite sensor, an optical path module, an optical circulator module, a spectrometer module, a signal processing module and a touch display module;
the optical circulator module comprises a first port, a second port and a third port, wherein the first port is communicated with the second port in one way, and the second port is communicated with the third port in one way;
the output end of the optical path module is in optical path connection with the first port of the optical circulator module and is used for generating a broadband optical signal;
The optical fiber double-FP composite sensor is in optical path connection with the second port of the optical circulator module and is used for receiving the broadband optical signal and sending the reflected optical signal of the optical fiber double-FP composite sensor back to the second port of the optical circulator module;
the spectrometer module is connected with a third port optical path of the optical circulator module and is used for receiving the reflected light signal, carrying out spectrum acquisition and outputting spectrum information;
the signal processing module is respectively connected with the light path module and the spectrometer module in a signal way and is used for providing power supply voltage for the light path module or receiving spectrum information output by the spectrometer module to demodulate the cavity length information of the optical fiber double-FP composite sensor;
the touch display module is in communication connection with the signal processing module and is used for displaying and outputting cavity length demodulation information or touch input.
On the basis of the above technical solution, preferably, the optical fiber dual FP composite sensor includes:
a single mode optical fiber;
The hollow optical fiber is arranged at one end of the single-mode optical fiber in the axial extending direction and extends outwards in the direction away from the single-mode optical fiber; a through cavity is arranged at the center of the hollow optical fiber;
a filling part which is arranged in the hollow optical fiber and is arranged at one side end part where the single-mode optical fiber is positioned;
The coreless optical fiber is arranged at one end of the hollow optical fiber far away from the single-mode optical fiber and extends outwards in the direction far away from the hollow optical fiber;
Wherein, the single-mode optical fiber, the filling part and one end of the hollow optical fiber form a first FP cavity; the filling portion, the unfilled section of hollow fiber and coreless fiber form a second FP cavity.
Preferably, when the optical path module outputs broadband light, the output spectrum I R0 of the optical fiber dual FP composite sensor is expressed as: Wherein/> Representing the contrast of the background light signal; /(I)Representing contrast of the white light interference signal; /(I)Is the phase of the interference spectrum; /(I)The cavity length of a second FP cavity of the optical fiber double-FP composite sensor; /(I)Is the wavelength of the light source; /(I)Phase changes occurring during broadband light propagation and reflection; so according to different light source wavelength/>And/>Phase difference/>, betweenExpressed as: /(I)The cavity length/>, of the second FP cavity of the optical fiber double-FP composite sensor can be obtained according to the wavelength and the phase in the interference spectrum。
Preferably, the optical fiber double-FP composite sensor is manufactured by the following steps:
S1: selecting a single-mode fiber, a hollow fiber and a coreless fiber, removing a coating layer on the surface of each fiber, and wiping by dipping alcohol with dust-free paper; cutting one end of a single-mode fiber and one end of a coreless fiber to be flat, and cutting two ends of a hollow fiber to be flat;
s2: immersing the flattened hollow fiber end in PMMA solution with the concentration of 0.125g/ml, wherein the solvent is acetone solution, and controlling the length of the hollow fiber end entering a polymer section;
S3: standing the hollow optical fiber filled with the polymer solution for a period of time in a room temperature environment, and taking a polymer section in the hollow optical fiber as a filling part after the acetone solution is completely volatilized; placing cut flat ends of one end of the hollow optical fiber where the filling part is positioned and the single-mode optical fiber into an optical fiber fusion splicer respectively for fusion splicing;
s4: the length of the hollow optical fiber which is not filled with polymer is reserved, and the other end of the hollow optical fiber is welded with the cut flat end part of the coreless optical fiber;
s5: cutting and grinding the length of the coreless optical fiber, and reducing the axial length of the coreless optical fiber.
Preferably, the light path module comprises an SLD light source, a first direct current voltage reduction circuit, a temperature control circuit and a constant current driving circuit; the first direct current voltage reducing circuit is respectively provided with a power supply with the SLD light source, the temperature control circuit and the constant current driving circuit; the temperature control circuit is used for maintaining the working temperature of the SLD light source; the constant current driving circuit is also in communication connection with the signal processing module, and the output end of the constant current driving circuit is electrically connected with the input end of the SLD light source and is used for providing constant driving current for the SLD light source.
Preferably, the temperature control circuit comprises a thermistor with a negative temperature coefficient, a precision resistor, a semiconductor refrigeration chip TEC and an analog-to-digital converter, wherein the thermistor is arranged on the surface of the SLD light source and is used for acquiring a temperature signal of the surface of the SLD light source; one end of the thermistor is electrically connected with the reference voltage, the other end of the thermistor is respectively electrically connected with one end of the precision resistor and the input end of the analog-to-digital converter, the output end of the analog-to-digital converter is in communication connection with the signal processing module, and the other end of the precision resistor is grounded; the cold end of the semiconductor refrigeration piece TEC is attached to the surface of the SLD light source, and the signal processing module drives the semiconductor refrigeration piece TEC to work so as to stabilize the temperature of the SLD light source.
Preferably, the signal processing module comprises a hardware circuit submodule and a demodulation algorithm submodule; the hardware circuit submodule comprises a second direct-current voltage reduction circuit, an MCU, an SPI interface circuit, a touch screen interface circuit, a TF card memory circuit, a program burning circuit and a USB serial circuit; the second direct current voltage reduction circuit is used for converting input voltage into different power supply voltages for an MCU, an SPI interface circuit, a touch screen interface circuit, a TF card storage circuit, a program burning circuit or a USB serial port circuit; the MCU is respectively and electrically connected with the SPI interface circuit, the touch screen interface circuit, the TF card storage circuit, the program burning circuit and the USB serial port circuit; the SPI interface circuit is also in communication connection with the constant current driving circuit; the touch screen interface circuit is also electrically connected with the touch screen; the TF card storage circuit is used for storing demodulation information; the program burning circuit is used for burning and solidifying the program; the USB serial circuit is used for being in communication connection with the spectrometer module and receiving spectrum information output by the spectrometer; and the demodulation algorithm submodule acquires the spectrum information output by the spectrometer and then carries out algorithm demodulation.
Preferably, the demodulation algorithm submodule acquires spectral information output by the spectrometer and then carries out algorithm demodulation, and the method specifically comprises the following steps:
1) Collecting spectrum data: the optical fiber double-FP composite sensor (1) generates a reflected light signal to the input broadband light, the spectrometer module (4) receives the reflected light, performs photoelectric conversion, amplification, filtering and analog-to-digital conversion processing on the reflected light, sends the obtained data to the upper computer through serial port communication, and obtains the reflected spectrum data of the optical fiber double-FP composite sensor (1) after receiving and analyzing by the upper computer, wherein a sensing model of the interference light signal of the optical fiber double-FP composite sensor (1) is as follows: Wherein/> Is the reflectivity at the FP cavity end face; /(I)Refractive index of medium in FP cavity; l 1 and L 2 are the cavity lengths of a first FP cavity and a second FP cavity of the optical fiber double-FP composite sensor (1) respectively; /(I)Is the light intensity, when the light source is a broadband light source, the expression of the light intensity is/>Let/>Peak half-width, frequency parameter/>, of a gaussian distributed broadband light sourceFor/>C is the speed of light; /(I)Is the frequency of the light wave; /(I)The optical wave frequency is the center wavelength of a Gaussian distributed broadband light source; /(I)A center wavelength of a gaussian distributed broadband light source; pair/>Taylor expansion is carried out on the index part of the (E) to obtain a first order approximation, so that/>Wherein the parameters are，/>Substituting the interference light signal into the expression of the interference light signal to obtain:；
2) Interference spectrum signal fast fourier transform: performing fast fourier transform on the interference optical signal I R to obtain the expression in the frequency domain: k is wave number; j is an imaginary unit; n is the number of spectral Fourier transform points, and/> ; Let/>The wave number k with the maximum value is recorded as k L; according to the frequency formulaAnd angular frequency equation/>，/>Solving to obtain the cavity length L 2 of the second FP cavity of the optical fiber double-FP composite sensor (1) as follows: /(I)；
3) Solving k L by using full phase information: the corresponding phase at k L after fourier transform of the spectral signal is:，/> is a real number; /(I) Phase change during broadband light propagation and reflection; k1 and k0 are the initial wave number and the final wave number of the spectrum, respectively, and the above formula is rewritten to obtain/>The expression of (2) is: Will/> The expression of k L obtained after the writing is as follows:，/> Is a rounding operation;
4) Calculating the cavity length: substituting the obtained value of k L into the cavity length formula of the second FP cavity of the optical fiber double-FP compound sensor (1) in the step 2) The cavity length can be obtained.
Preferably, when the signal processing module is in communication with the constant current driving circuit of the light path module, junction temperature of a chip used by the constant current driving circuit is also obtained：/>，/>In order to detect the voltage, if the junction temperature exceeds the preset temperature, the constant current driving circuit outputs fault warning information.
Preferably, the touch display module is used for displaying the historical data and the current data of the cavity length of the second FP cavity of the optical fiber double-FP composite sensor obtained through demodulation of the signal processing module.
Compared with the prior art, the optical fiber double-FP composite sensing monitoring equipment provided by the invention has the following beneficial effects:
(1) The optical fiber double-FP composite sensor is constructed, and is integrated with the peripheral optical path module, the spectrometer module and the signal processing module to form the composite sensing monitoring equipment, so that the optical fiber double-FP composite sensor is compact in structure, small in size and suitable for more complex working condition environments while being sensitive to pressure sensing;
(2) The optical fiber double-FP composite sensor with electromagnetic interference resistance and corrosion resistance is constructed by organically combining the single-mode optical fiber, the hollow optical fiber and the coreless optical fiber and further generating a polymer filling part, so that high-precision and sensitive composite measurement on temperature-pressure can be well realized;
(3) The application adopts the high-precision cavity length demodulation algorithm based on the combination of the fast Fourier transform and the full-phase information, compared with the existing demodulation algorithm, the high-precision cavity length demodulation algorithm has higher precision, can store the spectrum information and the demodulation result information through a TF card read-write mechanism, and is convenient for long-time detection and analysis; and further performs data interaction with the user through the touch display module.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a block diagram of an optical fiber dual-FP composite sensing and monitoring device;
FIG. 2 is a schematic diagram of a fiber-optic dual-FP composite sensor of the fiber-optic dual-FP composite sensing monitoring device of the present invention;
FIG. 3 is a schematic diagram of steps for manufacturing an optical fiber dual-FP composite sensor of the optical fiber dual-FP composite sensing monitoring device of the invention;
FIG. 4 is a schematic diagram of the driving steps of the constant current driving circuit of the optical fiber dual-FP composite sensing monitoring device;
FIG. 5 is a block diagram of the hardware circuit sub-module of the signal processing module of the optical fiber dual-FP composite sensing monitoring device;
FIG. 6 is an algorithm processing flow chart of a demodulation algorithm sub-module of the signal processing module of the optical fiber double-FP composite sensing monitoring device of the invention;
Fig. 7 is a functional schematic diagram of a touch display module of the optical fiber dual FP composite sensing monitoring device of the present invention.
Detailed Description
The following description of the embodiments of the present invention will clearly and fully describe the technical aspects of the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, are intended to fall within the scope of the present invention.
As shown in fig. 1, the invention provides an optical fiber dual-FP composite sensing monitoring device, which comprises an optical fiber dual-FP composite sensor 1, an optical path module 2, an optical circulator module 3, a spectrometer module 4, a signal processing module 5, a touch display module 6 and the like. Wherein:
The optical path module 2 is used for generating a broadband optical signal. The optical circulator module 3 comprises a first port, a second port and a third port, wherein the first port is communicated with the second port in one way, and the second port is communicated with the third port in one way; the first port is also called an input port and is welded with the optical path module 1 through an optical fiber welding machine and used for transmitting broadband light to the sensor; the second port is connected with the optical fiber double-FP composite sensor 1 by adopting a flange plate, and the second port not only transmits broadband optical signals to the optical fiber double-FP composite sensor 1, but also receives reflected optical signals of the optical fiber double-FP composite sensor 1; the third port is also called an output port and is connected with the spectrometer module 4 through a flange plate, and the reflected light signals are transmitted to the micro spectrometer in a unidirectional way to perform spectrum acquisition.
The signal processing module 5 is respectively connected with the optical path module 2 and the spectrometer module 4 in a signal way and is used for providing power supply voltage for the optical path module 2 or receiving spectrum information output by the spectrometer module 4 to demodulate the cavity length information of the optical fiber double-FP composite sensor 1;
The spectrometer module 4 employs a bulk phase grating VPG as a spectral dispersive element and an ultra-sensitive InGaAs array detector as a detection element, providing high speed parallel processing and continuous spectral measurement. The device intercepts the signal from the main data transmission link through a single mode fiber and then collimates it with a microlens. The signals are spectrally dispersed under the VPG, the diffraction field is focused onto an InGaAs array detector, and the electronics are controlled to read out the processed digital signals to extract the desired information.
The touch display module 6 is in communication connection with the signal processing module 5 and is used for displaying and outputting cavity length demodulation information or touch input.
The three ports of the optical circulator module 3 respectively correspond to the optical path module 2, the optical fiber double-FP composite sensor 1 and three unidirectional optical paths of the spectrometer module 4, the spectrum information of the reflected light output by the spectrometer module 4 is further analyzed by the signal processing module 5, and the touch display module 6 performs user interaction display and input.
As shown in fig. 2, the optical fiber dual FP composite sensor 1 includes a single mode optical fiber, a hollow optical fiber, and a coreless optical fiber coaxially arranged in order; the hollow optical fiber is arranged at one end of the single-mode optical fiber in the axial extending direction and extends outwards in the direction away from the single-mode optical fiber; a through cavity is arranged at the center of the hollow optical fiber; the filling part is arranged in the hollow optical fiber and is arranged at one side end part where the single-mode optical fiber is positioned; the coreless optical fiber is arranged at one end of the hollow optical fiber far away from the single-mode optical fiber and extends outwards in the direction far away from the hollow optical fiber; a first FP cavity is formed by the single-mode optical fiber, the filling part and one end of the hollow optical fiber; the filling portion, the unfilled section of hollow fiber and coreless fiber form a second FP cavity. The optical fiber double-FP composite sensor 1 is a composite structure because of the two FP cavities.
As shown in fig. 3, the optical fiber dual FP composite sensor 1 may be manufactured by:
s1: selecting a single-mode fiber, a hollow fiber and a coreless fiber, removing a coating layer on the surface of each fiber, and wiping by dipping alcohol with dust-free paper; cutting one end of a single-mode fiber and one end of a coreless fiber to be flat, and cutting two ends of a hollow fiber to be flat; as in a of fig. 3.
S2: immersing the flattened hollow fiber end in PMMA solution with the concentration of 0.125g/ml, wherein the solvent is acetone solution, and controlling the length of the hollow fiber end entering a polymer section; as in B of fig. 3.
S3: standing the hollow optical fiber filled with the polymer solution for a period of time in a room temperature environment, and taking a polymer section in the hollow optical fiber as a filling part after the acetone solution is completely volatilized; placing cut flat ends of one end of the hollow optical fiber where the filling part is positioned and the single-mode optical fiber into an optical fiber fusion splicer respectively for fusion splicing; as in C of fig. 3.
S4: the length of the hollow optical fiber which is not filled with polymer is reserved, and the other end of the hollow optical fiber is welded with the cut flat end part of the coreless optical fiber; as shown at D in fig. 3.
S5: cutting and grinding the length of the coreless optical fiber, and reducing the axial length of the coreless optical fiber. The cutting and grinding process is referred to as E and F in fig. 3.
Assuming that the filling part is of a rigid circular structure; when the filling part is acted by the pressure P, the filling part deforms, so that the cavity length of the second FP cavity where the filling part is positioned changesThe method comprises the following steps: /(I)Wherein/>Poisson ratio for the filler; Young's modulus for the filling portion; /(I) Is the thickness of the filling part; /(I)Is the effective radius of the filling part; /(I)Is a change in the internal and external pressure difference acting on the filling portion; the deformation of the filling portion due to external pressure will result in a pressure sensitivity of the second FP cavity expressed as: /(I); Assuming the initial length of the second FP cavity is/>The wavelength of the peak of the spectrogram corresponding to the cavity length is/>Satisfy/>，/>Is the peak wavelength drift amount; the second FP cavity is subjected to temperature variation/>The peak wavelength shift resulting from the influence of (a) is expressed as/>Wherein/>Is a thermo-optical coefficient; /(I)Is the coefficient of thermal expansion. From the above, it can be seen that the cavity length change amount/>, of the second FP cavityIs related to the change of temperature and pressure, so the cavity length change amount/>, of the second FP cavity can be usedTo measure the temperature-pressure composite signal.
When the optical path module 2 outputs broadband light to the optical circulator module 3, the output spectrum I R0 of the optical fiber dual FP composite sensor 1 is expressed as: Wherein/> Representing the contrast of the background light signal; /(I)Representing contrast of the white light interference signal; /(I)Is the phase of the interference spectrum; /(I)The cavity length of the second FP cavity of the optical fiber double-FP composite sensor 1; /(I)Is the wavelength of the light source; /(I)Phase changes occurring during broadband light propagation and reflection; so according to different light source wavelength/>And/>Phase difference/>, betweenExpressed as: /(I)The cavity length/>, of the second FP cavity of the optical fiber double-FP composite sensor 1 can be obtained according to the wavelength and the phase change in the interference spectrum。
As further shown in fig. 1, the optical path module 2 includes an SLD light source 21, a first dc step-down circuit 22, a temperature control circuit 23, and a constant current drive circuit 24; the first direct current step-down circuit 22 supplies power to the SLD light source 22, the temperature control circuit 23, and the constant current drive circuit 24, respectively; the temperature control circuit 23 is used for maintaining the working temperature of the SLD light source 21; the constant current driving circuit 24 is further connected to the signal processing module 5 in a communication manner, and an output end of the constant current driving circuit 24 is electrically connected to an input end of the SLD light source 21, so as to provide a constant driving current for the SLD light source 21. The SLD light source 21 outputs broadband light with power of tens of milliwatts to tens of milliwatts, the SLD light source 21 is a super-radiation light-emitting diode light source, is a semiconductor light-emitting device with wide spectrum, weak time coherence, high power and high efficiency, and the SLD light source 21 spontaneously radiates photons in a wide spectrum range and is stimulated and amplified to generate laser; the SLD light source 21 adopts the coupling encapsulation of a standard 14-pin butterfly-shaped band tail fiber, when electrons reversely distributed in an active layer after forward current injection transition from a conduction band to a valence band or an impurity energy level, the electrons are combined with holes to release photons, and the photons of spontaneous radiation are amplified by the gain effect when the photons propagate in a given cavity. In the SLD semiconductor light source device, harmonic waves formed by reflection at the rear end thereof are insufficient to form laser light, incoherent light is output, but since the light is subjected to gain action on the way, the modulation bandwidth of the SLD device increases. The SLD light source 21 generates a large amount of heat during operation, and the temperature control circuit 23 detects and lowers the temperature, thereby maintaining the stability of the operation state of the SLD light source 21.
Specifically, the temperature control circuit 23 includes a thermistor with negative temperature coefficient, a precision resistor, a semiconductor refrigeration chip TEC and an analog-to-digital converter, where the thermistor is disposed on the surface of the SLD light source 21 and is used to obtain a temperature signal of the surface of the SLD light source 21; one end of the thermistor is electrically connected with a reference voltage, the other end of the thermistor is respectively electrically connected with one end of the precision resistor and the input end of the analog-to-digital converter, the output end of the analog-to-digital converter is in communication connection with the signal processing module 5, and the other end of the precision resistor is grounded; the cold end of the semiconductor refrigeration piece TEC is attached to the surface of the SLD light source 21, and the signal processing module 5 drives the semiconductor refrigeration piece TEC to work so as to stabilize the temperature of the SLD light source 21. After the SLD light source device is connected with a power supply to work, corresponding heat is generated, so that the temperature of the tube core of the luminous tube is increased, and the output power of the light source device and the accuracy of subsequent signal processing are affected. There are mainly two factors affecting the stability of the output optical power of the SLD light source 21: current and temperature, when the current is unchanged, the output optical power decreases with the increase of the temperature, so that the output power is unstable, which affects the performance of the SLD light source 21 device; similarly, when the temperature is unchanged, the output light power is increased along with the increase of the input current, so that the light source driving circuit for stabilizing the output light power starts from controlling the driving current and the semiconductor refrigerator, and indirectly stabilizes the output light power by stabilizing the driving current and the temperature, and the stability, the reliability and the durability of the light source are improved by adopting a constant current driving and constant temperature control scheme. The temperature signal of the SLD light source 21 is acquired through the thermistor to acquire the surface temperature of the SLD light source 21, and the refrigerating capacity of the semiconductor refrigerating plate TEC is fed back and adjusted, so that the temperature of the cold end of the semiconductor refrigerating plate TEC attached to the SLD light source 21 is kept stable, and the SLD light source 21 is kept in a stable working state. The built-in thermistor has a negative temperature coefficient, the resistance value is reduced along with the temperature rise, and the resistance value is 10KΩ at normal temperature, for example, 25 ℃; the thermistor can indicate the current temperature of the surface of the SLD light source 21 by the magnitude of the total resistance of the series of precision resistors of low temperature drift and constitute a closed loop feedback. The resistance temperature curve of the thermistor is nonlinear, and the resistance at a specific temperature can be obtained by looking up a table, so that the surface temperature of the corresponding SLD light source 21 is indirectly obtained.
The constant current driving circuit 24 is used for providing constant driving current for the SLD light source 21, the output end of the constant current driving circuit 24 is directly connected with the driving pin of the SLD light source 21 in a soldering manner, the constant current driving circuit 24 is composed of a constant current driving chip and peripheral circuits thereof, and the constant current driving chip can be an LTC2662 chip and is a typical application circuit of the chip. As shown in fig. 4, the process of establishing the communication protocol between the signal processing module 5 and the constant current drive circuit 24 includes the steps of:
step 1: and the welding of the constant current driving chip and surrounding circuits is ensured to be correct, and the voltage of each functional pin is detected to be normal.
Step 2: and writing an internal reference command, adopting a mode one method of CPHA=0 and CPOL=0 to ensure that the reference voltage selection pins are connected correctly, writing RD bit into 0 through a Config command to disable an external reference, and adopting an internal high-precision reference voltage. The command header "0111" and the command tail "0000".
Step 3: the instruction of disabling the inversion function is written, and because the constant current driving chip internally comprises A, B double registers to support the reading of different working instructions, the switching of the double working modes can be simply and quickly realized. The command header "1100", the command tail "0_0000".
Step 4: and writing a specified channel range instruction, setting the range of the specified channel through a command head '0110', and adjusting the position of a corresponding potentiometer in the chip by adopting 4-bit binary coding to set eight full-scale ranges of 3.125mA, 6.25mA, 12.5mA, 25mA, 50mA, 100mA, 200mA, 300mA and the like. The tail "0111" is commanded.
Step 5: writing a specified channel output current instruction, wherein one of the two modes is writing a register and updating, namely executing codes simultaneously when writing a command; and secondly, the register writing instruction is electrified and updated when any need arises, so that the functions are more diversified. The instruction is 16-bit binary, and the magnitude of the output current is determined according to the input instruction and the range code. If the channel range is set to L, the input instruction is set to I in, and the input range is 0-65536, the current LI in/65536 is output. Writing and updating functions: command header "0011", write register function: "0000".
Step 6: the test function instruction of the detection pin is compiled, the chip is selected to be provided with an independent detection pin for testing the working condition of the chip, and parameters such as reference voltage, power supply voltage, ground plane voltage, appointed output channel voltage and current, chip temperature and the like can be tested. The above function is binary coded by the command tail 5 bits, which commands the head "1011".
Step 7: and writing a read register return command instruction to detect whether the 4-wire SPI communication pin is normal. When an SPI communication command is sent, the chip returns a 32-bit binary command read from a designated register, the first 8 bits are fault flag bits, and if the conditions of command errors, over-temperature, overload, open channel and the like occur, the corresponding flag bit is at a position of 1. Using a read chip temperature command, the sense pin voltage is linearly related to temperature, the temperature coefficient is-3.7 mV/°C,To detect voltage, the junction temperature is measuredThe method comprises the following steps:
the rest 24 bits return the content of the last instruction, and a read instruction is written to check whether SPI communication is normally established. If the junction temperature exceeds the preset temperature, the constant current drive circuit 24 outputs a fault warning message.
As shown in fig. 5, the signal processing module 5 includes a hardware circuit sub-module and a demodulation algorithm sub-module; the hardware circuit submodule comprises a second direct-current voltage-reducing circuit 51, an MCU52, an SPI interface circuit 53, a touch screen interface circuit 54, a TF card memory circuit 55, a program burning circuit 56 and a USB serial port circuit 57; the second dc voltage-reducing circuit 51 is configured to convert an input voltage into different power supply voltages, and is used by the MCU52, the SPI interface circuit 53, the touch screen interface circuit 54, the TF card memory circuit 55, the program recording circuit 56, or the USB serial circuit 57; MCU52 is electrically connected with SPI interface circuit 53, touch screen interface circuit 54, TF card memory circuit 55, program burning circuit 56 and USB serial circuit 57; SPI interface circuit 53 is also communicatively coupled to constant current drive circuit 24; the touch screen interface circuit 54 is also electrically connected to the touch screen; the TF card storage circuit 55 is used for storing demodulation information; the program burning circuit 56 is used for burning and solidifying the program; the USB serial circuit 57 is used for being in communication connection with the spectrometer module 4, and receiving the spectrum information output by the spectrometer; and the demodulation algorithm submodule acquires the spectrum information output by the spectrometer and then carries out algorithm demodulation.
As shown in fig. 6, in the above description, the demodulation algorithm submodule acquires the spectrum information output by the spectrometer and then performs algorithm demodulation, and specifically includes the following steps:
1) Collecting spectrum data: the optical fiber double-FP composite sensor (1) generates a reflected light signal to the input broadband light, the spectrometer module (4) receives the reflected light, performs photoelectric conversion, amplification, filtering and analog-to-digital conversion processing on the reflected light, sends the obtained data to the upper computer through serial port communication, and obtains the reflected spectrum data of the optical fiber double-FP composite sensor (1) after receiving and analyzing by the upper computer, wherein a sensing model of the interference light signal of the optical fiber double-FP composite sensor (1) is as follows: Wherein/> Is the reflectivity at the FP cavity end face; refractive index of medium in FP cavity; l 1 and L 2 are the cavity lengths of a first FP cavity and a second FP cavity of the optical fiber double-FP composite sensor (1) respectively; /(I) Is the light intensity, when the light source is a broadband light source, the expression of the light intensity is/>Let/>Peak half-width, frequency parameter/>, of a gaussian distributed broadband light sourceFor/>C is the speed of light; /(I)Is the frequency of the light wave; /(I)The optical wave frequency is the center wavelength of a Gaussian distributed broadband light source; /(I)A center wavelength of a gaussian distributed broadband light source; pair/>Taylor expansion is carried out on the index part of the (E) to obtain a first order approximation, so that/>Wherein the parameters are，/>Substituting the interference light signal into the expression of the interference light signal to obtain:；
2) Interference spectrum signal fast fourier transform: performing fast fourier transform on the interference optical signal I R to obtain the expression in the frequency domain: k is wave number; j is an imaginary unit; n is the number of spectral Fourier transform points, and/> ; Let/>The wave number k with the maximum value is recorded as k L; according to the frequency formulaAnd angular frequency equation/>，/>Solving to obtain the cavity length L 2 of the second FP cavity of the optical fiber double-FP composite sensor (1) as follows: /(I)；
3) Solving k L by using full phase information: the corresponding phase at k L after fourier transform of the spectral signal is:，/> is a real number; /(I) Phase change during broadband light propagation and reflection; k1 and k0 are the initial wave number and the final wave number of the spectrum, respectively, and the above formula is rewritten to obtain/>The expression of (2) is: Will/> The expression of k L obtained after the writing is as follows:，/> Is a rounding operation;
4) Calculating the cavity length: substituting the obtained value of k L into the cavity length formula of the second FP cavity of the optical fiber double-FP compound sensor (1) in the step 2) The cavity length can be obtained.
As shown in fig. 1 and fig. 7, the touch display module 6 is configured to display the historical data and the current data of the cavity length of the second FP cavity of the optical fiber dual FP composite sensor 1 obtained by demodulating the signal processing module 5. Clicking the threshold early warning module of the touch display screen can set the threshold of the cavity length, and realizing early warning display of numerical values; clicking a historical data review module of the touch display screen to realize the review of the call historical cavity length data; clicking the touch display screen demodulation setting module to realize the operation of the demodulation system, and the demodulation system realizes the corresponding demodulation function according to the touch screen setting.
Four pages are set in the touch display module 6: the system comprises an initial page, a threshold early warning page, a historical data page and a demodulation setting page. By defining a series of ID constants, such as a base value GUI_ID_USER plus an offset, the four pages are set to identify different controls in the GUI, and clicking the controls can call out the relevant pages.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (8)
1. The optical fiber double-FP composite sensing monitoring device is characterized by comprising an optical fiber double-FP composite sensor (1), an optical path module (2), an optical circulator module (3), a spectrometer module (4), a signal processing module (5) and a touch display module (6);
the optical circulator module (3) comprises a first port, a second port and a third port, wherein the first port is in unidirectional communication with the second port, and the second port is in unidirectional communication with the third port;
The output end of the optical path module (2) is in optical path connection with the first port of the optical circulator module (3) and is used for generating a broadband optical signal;
The optical fiber double-FP composite sensor (1) is in optical path connection with the second port of the optical circulator module (3) and is used for receiving a broadband optical signal and sending a reflected optical signal of the optical fiber double-FP composite sensor (1) back to the second port of the optical circulator module (3);
The spectrometer module (4) is connected with a third port optical path of the optical circulator module (3) and is used for receiving the reflected light signals, carrying out spectrum acquisition and outputting spectrum information;
the signal processing module (5) is respectively connected with the optical path module (2) and the spectrometer module (4) in a signal way and is used for providing power supply voltage for the optical path module (2) or receiving spectrum information output by the spectrometer module (4) to demodulate the cavity length information of the optical fiber double-FP composite sensor (1);
the touch display module (6) is in communication connection with the signal processing module (5) and is used for displaying and outputting cavity length demodulation information or touch input;
The signal processing module (5) comprises a hardware circuit submodule and a demodulation algorithm submodule; the hardware circuit submodule comprises a second direct-current voltage reduction circuit (51), an MCU (52), an SPI interface circuit (53), a touch screen interface circuit (54), a TF card storage circuit (55), a program burning circuit (56) and a USB serial port circuit (57); the second direct current voltage reduction circuit (51) is used for converting input voltage into different power supply voltages for the MCU (52), the SPI interface circuit (53), the touch screen interface circuit (54), the TF card storage circuit (55), the program burning circuit (56) or the USB serial circuit (57); the MCU (52) is electrically connected with the SPI interface circuit (53), the touch screen interface circuit (54), the TF card storage circuit (55), the program burning circuit (56) and the USB serial port circuit (57) respectively; the SPI interface circuit (53) is also in communication connection with the constant current drive circuit (24); the touch screen interface circuit (54) is also electrically connected with the touch screen; the TF card memory circuit (55) is used for storing demodulation information; the program burning circuit (56) is used for burning and solidifying the program; the USB serial circuit (57) is used for being in communication connection with the spectrometer module (4) and receiving spectrum information output by the spectrometer; the demodulation algorithm submodule acquires spectrum information output by the spectrometer and then carries out algorithm demodulation;
The demodulation algorithm submodule carries out algorithm demodulation after obtaining the spectrum information output by the spectrometer, and specifically comprises the following steps:
1) Collecting spectrum data: the optical fiber double-FP composite sensor (1) generates a reflected light signal to the input broadband light, the spectrometer module (4) receives the reflected light, performs photoelectric conversion, amplification, filtering and analog-to-digital conversion processing on the reflected light, sends the obtained data to the upper computer through serial port communication, and obtains the reflected spectrum data of the optical fiber double-FP composite sensor (1) after receiving and analyzing by the upper computer, wherein a sensing model of the interference light signal of the optical fiber double-FP composite sensor (1) is as follows:
Wherein R is the reflectivity at the end face of the FP cavity; n 0 is the refractive index of the medium in the FP cavity; l 1 and L 2 are the cavity lengths of a first FP cavity and a second FP cavity of the optical fiber double-FP composite sensor (1) respectively; i 0 is the light intensity, and when the light source is a broadband light source, the expression of the light intensity is Let the bandwidth of the broadband light source be B and the frequency parameter delta λ be/>C is the speed of light; v is the frequency of the light wave; v p is the optical wave frequency of the center wavelength of the Gaussian distributed broadband light source; a center wavelength of a broadband light source with lambda p Gaussian distribution; taylor expansion is carried out on the index part of I 0 (v) to obtain a first order approximation, so as to obtain/>Wherein the parameter isΔ=c/v, substituted into the expression of the interference light signal, resulting in: /(I)
2) Interference spectrum signal fast fourier transform: performing fast fourier transform on the interference optical signal I R to obtain the expression in the frequency domain: k is wave number; j is an imaginary unit; n is the number of spectral fourier transform points, and n=0, 1,2 …, N-1; let k, the wave number when the value of |X (k) | is the maximum, be k L; according to a frequency formula omega L＝2πkL/N and an angular frequency formula omega L＝4πL/c,ωL＝ΩL·δυ, solving to obtain the cavity length L 2 of the second FP cavity of the optical fiber double-FP composite sensor (1) as follows:
3) Solving k L by using full phase information: the corresponding phase at k L after fourier transform of the spectral signal is: a is a real number; /(I) Phase change during broadband light propagation and reflection; k1 and k0 are the start wave number and the end wave number of the spectrum, respectively, and the expression of a obtained by rewriting the above formula is: The expression of k L obtained after rewriting by substituting the rounded-up a into the above expression is: [. Cndot ] is a rounding operation;
4) Calculating the cavity length: substituting the obtained value of k L into the cavity length formula of the second FP cavity of the optical fiber double-FP compound sensor (1) in the step 2) The cavity length can be obtained.
2. The optical fiber dual FP composite sensing and monitoring device of claim 1, wherein the optical fiber dual FP composite sensor (1) comprises:
a single mode optical fiber;
The hollow optical fiber is arranged at one end of the single-mode optical fiber in the axial extending direction and extends outwards in the direction away from the single-mode optical fiber; a through cavity is arranged at the center of the hollow optical fiber;
a filling part which is arranged in the hollow optical fiber and is arranged at one side end part where the single-mode optical fiber is positioned;
The coreless optical fiber is arranged at one end of the hollow optical fiber far away from the single-mode optical fiber and extends outwards in the direction far away from the hollow optical fiber;
Wherein, the single-mode optical fiber, the filling part and one end of the hollow optical fiber form a first FP cavity; the filling portion, the unfilled section of hollow fiber and coreless fiber form a second FP cavity.
3. The optical fiber dual FP composite sensing and monitoring device according to claim 2, wherein when the optical path module (2) outputs broadband light, the output spectrum I R0 of the optical fiber dual FP composite sensor (1) is represented as: Wherein a (λ) represents the contrast of the background light signal; b (λ) represents the contrast of the white light interference signal; phi is the phase of the interference spectrum; l is the cavity length of a second FP cavity of the optical fiber double-FP composite sensor (1); lambda is the light source wavelength; /(I) Phase changes occurring during broadband light propagation and reflection; the phase difference ΔΦ between the different light source wavelengths λ 1 and λ 2 is expressed as: /(I)The cavity length L of the second FP cavity of the optical fiber double-FP composite sensor (1) can be obtained according to the wavelength and the phase in the interference spectrum.
4. The optical fiber double-FP composite sensor monitoring apparatus according to claim 3, wherein the optical fiber double-FP composite sensor (1) is manufactured by:
S1: selecting a single-mode fiber, a hollow fiber and a coreless fiber, removing a coating layer on the surface of each fiber, and wiping by dipping alcohol with dust-free paper; cutting one end of a single-mode fiber and one end of a coreless fiber to be flat, and cutting two ends of a hollow fiber to be flat;
s2: immersing the flattened hollow fiber end in PMMA solution with the concentration of 0.125g/ml, wherein the solvent is acetone solution, and controlling the length of the hollow fiber end entering a polymer section;
S3: standing the hollow optical fiber filled with the polymer solution for a period of time in a room temperature environment, and taking a polymer section in the hollow optical fiber as a filling part after the acetone solution is completely volatilized; placing cut flat ends of one end of the hollow optical fiber where the filling part is positioned and the single-mode optical fiber into an optical fiber fusion splicer respectively for fusion splicing;
s4: the length of the hollow optical fiber which is not filled with polymer is reserved, and the other end of the hollow optical fiber is welded with the cut flat end part of the coreless optical fiber;
s5: cutting and grinding the length of the coreless optical fiber, and reducing the axial length of the coreless optical fiber.
5. The optical fiber dual FP composite sensing and monitoring device according to claim 3, wherein the optical path module (2) comprises an SLD light source (21), a first dc voltage reduction circuit (22), a temperature control circuit (23), and a constant current drive circuit (24); the first direct current voltage reducing circuit (22) is respectively provided with a power supply with the SLD light source (21), the temperature control circuit (23) and the constant current driving circuit (24); the temperature control circuit (23) is used for maintaining the working temperature of the SLD light source (21); the constant current driving circuit (24) is also in communication connection with the signal processing module (5), and the output end of the constant current driving circuit (24) is electrically connected with the input end of the SLD light source (21) and is used for providing constant driving current for the SLD light source (21).
6. The optical fiber dual-FP composite sensing and monitoring device according to claim 5, wherein the temperature control circuit (23) comprises a thermistor with a negative temperature coefficient, a precision resistor, a semiconductor refrigeration chip TEC and an analog-to-digital converter, and the thermistor is arranged on the surface of the SLD light source (21) and is used for acquiring a temperature signal of the surface of the SLD light source (21); one end of the thermistor is electrically connected with a reference voltage, the other end of the thermistor is respectively electrically connected with one end of the precision resistor and the input end of the analog-to-digital converter, the output end of the analog-to-digital converter is in communication connection with the signal processing module (5), and the other end of the precision resistor is grounded; the cold end of the semiconductor refrigeration piece TEC is attached to the surface of the SLD light source (21), and the signal processing module (5) drives the semiconductor refrigeration piece TEC to work so as to stabilize the temperature of the SLD light source (21).
7. The optical fiber dual-FP composite sensing and monitoring device according to claim 1, wherein when the signal processing module (5) communicates with the constant current driving circuit (24) of the optical path module (2), the junction temperature T j：Tj＝25℃+(1.4-Vc)/(3.7mV/℃),Vc of a chip used by the constant current driving circuit (24) is also obtained as a detection voltage, and if the junction temperature exceeds a preset temperature, the constant current driving circuit (24) outputs fault alarm information.
8. The optical fiber dual-FP composite sensing monitoring device according to claim 1, wherein the touch display module (6) is configured to display historical data and current data of a cavity length of a second FP cavity of the optical fiber dual-FP composite sensor (1) obtained by demodulating by the signal processing module (5).
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Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040105345A (en) * | 2003-06-07 | 2004-12-16 | 주식회사 아이세스 | Strain measurement module using temperature controllable tunable light generator and fiberoptic system thereof |
| CN103344277A (en) * | 2013-06-26 | 2013-10-09 | 华中科技大学 | Fabry-Perot sensor capable of simultaneously detecting double parameters and detection device |
| CN105486407A (en) * | 2014-09-18 | 2016-04-13 | 陶建臣 | OMAP-L137-based portable static Fourier transform spectrometer |
| CN205248613U (en) * | 2015-11-08 | 2016-05-18 | 中国计量学院 | Drive of semiconductor laser power and temperature control device |
| CN106248121A (en) * | 2016-08-11 | 2016-12-21 | 天津大学 | Fluctuate under environment alternating temperature the fiber grating sensing demodulation device and demodulation method suppressed |
| CN107024236A (en) * | 2017-05-27 | 2017-08-08 | 成都凯天电子股份有限公司 | F P/FBG fibre optical sensor demodulating systems |
| CN108955734A (en) * | 2018-06-08 | 2018-12-07 | 武汉理工大学 | A kind of cavity length demodulating method of fiber F-P temperature/pressure compound sensor |
| CN111315632A (en) * | 2017-10-24 | 2020-06-19 | 蒂森克虏伯普利斯坦股份公司 | Steering column for a motor vehicle |
| AU2020101628A4 (en) * | 2020-08-03 | 2020-09-10 | Guilin Univ. Electr. Techol. | An intracavity-enhanced dual-wavelength common-path phase microscopy imaging measurement system based on an F-P interferometer |
| CN111707304A (en) * | 2020-07-29 | 2020-09-25 | 武汉理工大学 | Method for rapidly demodulating discrete cavity length of variable-step-length optical fiber F-P sensor |
| CN111707303A (en) * | 2020-07-17 | 2020-09-25 | 武汉理工大学 | Variable-step-length rapid high-precision signal demodulation method for optical fiber F-P sensor |
| CN111998884A (en) * | 2020-07-14 | 2020-11-27 | 重庆邮电大学 | Wavelength self-calibration optical fiber FP sensor demodulation method |
| CN112197849A (en) * | 2020-09-18 | 2021-01-08 | 华中科技大学 | Sound wave measuring system and method |
| CN115868946A (en) * | 2022-08-10 | 2023-03-31 | 绍兴市上虞区武汉理工大学高等研究院 | Temperature-pressure integrated fiber grating sensor and human sleep multi-body sign monitoring system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6961120B2 (en) * | 2003-11-05 | 2005-11-01 | Korea Electric Power Corporation | Strain measurement module with tunable light generator and strain measurement system using the same |
| CN101852655B (en) * | 2010-04-13 | 2012-04-18 | 中国计量学院 | Distributed fiber Raman/Brillouin scattering sensor |
| US9677933B2 (en) * | 2012-08-30 | 2017-06-13 | University of Maribor | Fiber-optic measurement system and methods based on ultra-short cavity length Fabry-Perot sensors and low resolution spectrum analysis |
-
2024
- 2024-02-04 CN CN202410157989.0A patent/CN117686009B/en active Active
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040105345A (en) * | 2003-06-07 | 2004-12-16 | 주식회사 아이세스 | Strain measurement module using temperature controllable tunable light generator and fiberoptic system thereof |
| CN103344277A (en) * | 2013-06-26 | 2013-10-09 | 华中科技大学 | Fabry-Perot sensor capable of simultaneously detecting double parameters and detection device |
| CN105486407A (en) * | 2014-09-18 | 2016-04-13 | 陶建臣 | OMAP-L137-based portable static Fourier transform spectrometer |
| CN205248613U (en) * | 2015-11-08 | 2016-05-18 | 中国计量学院 | Drive of semiconductor laser power and temperature control device |
| CN106248121A (en) * | 2016-08-11 | 2016-12-21 | 天津大学 | Fluctuate under environment alternating temperature the fiber grating sensing demodulation device and demodulation method suppressed |
| CN107024236A (en) * | 2017-05-27 | 2017-08-08 | 成都凯天电子股份有限公司 | F P/FBG fibre optical sensor demodulating systems |
| EP3700800A1 (en) * | 2017-10-24 | 2020-09-02 | thyssenkrupp Presta AG | Steering column for a motor vehicle |
| CN111315632A (en) * | 2017-10-24 | 2020-06-19 | 蒂森克虏伯普利斯坦股份公司 | Steering column for a motor vehicle |
| CN108955734A (en) * | 2018-06-08 | 2018-12-07 | 武汉理工大学 | A kind of cavity length demodulating method of fiber F-P temperature/pressure compound sensor |
| CN111998884A (en) * | 2020-07-14 | 2020-11-27 | 重庆邮电大学 | Wavelength self-calibration optical fiber FP sensor demodulation method |
| CN111707303A (en) * | 2020-07-17 | 2020-09-25 | 武汉理工大学 | Variable-step-length rapid high-precision signal demodulation method for optical fiber F-P sensor |
| CN111707304A (en) * | 2020-07-29 | 2020-09-25 | 武汉理工大学 | Method for rapidly demodulating discrete cavity length of variable-step-length optical fiber F-P sensor |
| AU2020101628A4 (en) * | 2020-08-03 | 2020-09-10 | Guilin Univ. Electr. Techol. | An intracavity-enhanced dual-wavelength common-path phase microscopy imaging measurement system based on an F-P interferometer |
| CN112197849A (en) * | 2020-09-18 | 2021-01-08 | 华中科技大学 | Sound wave measuring system and method |
| CN115868946A (en) * | 2022-08-10 | 2023-03-31 | 绍兴市上虞区武汉理工大学高等研究院 | Temperature-pressure integrated fiber grating sensor and human sleep multi-body sign monitoring system |
Non-Patent Citations (7)
| Title |
|---|
| A high-temperature resistant photonic crystal fiber sensor with single-side sliding Fabry-Perot cavity for super-large strain measurement;Ping Xia等;Sensors and Actuators A: Physical;20201010;第1-7页 * |
| Recent Advances and Tendency in Fiber Bragg Grating-Based Vibration Sensor: A Review;Tianliang Li等;IEEE SENSORS JOURNAL;20201015;第20卷(第20期);第12074-12087页 * |
| 双F-P 型高温/应变复合光纤传感器;郭煜恩等;传感技术学报;20230228;第36卷(第2期);第198-203页 * |
| 双F-P高温/大应变复合光纤传感器设计及其传感特性研究;吕文强;中国优秀硕士学位论文全文数据库信息科技辑;20230215(第2期);第11-43页 * |
| 吕文强.双F-P高温/大应变复合光纤传感器设计及其传感特性研究.中国优秀硕士学位论文全文数据库信息科技辑.2023,(第2期),第11-43页. * |
| 基于非本征F-P干涉技术的全光纤位移测量系统;马英瀚等;计量学报;20231231;第44卷(第12期);第1799-1804页 * |
| 法布里-珀罗光学微腔及其应用;刘清权等;光学学报;20230831;第43卷(第16期);第1623009-1至1623009-25页 * |
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