Self-calibration high-temperature-resistant optical fiber temperature-vibration double-parameter sensor

Abstract

The invention belongs to the field of high-temperature sensing, and discloses a self-calibration high-temperature-resistant optical fiber temperature-vibration double-parameter sensor which comprises a packaging base, a packaging cover plate, a packaging sleeve, an optical fiber, a Bragg fiber grating and a sensitive diaphragm. The packaging cover plate is fixedly connected with the packaging base, a first diaphragm groove is formed in the top of the packaging base, a second diaphragm groove is formed in the bottom of the packaging cover plate, and the first diaphragm groove and the second diaphragm groove are oppositely arranged to form a vibration space of the sensitive diaphragm; the Bragg fiber grating is provided with a first Bragg grating and a second Bragg grating, the first Bragg grating is fixed on the packaging cover plate, and the second Bragg grating is fixedly arranged on the sensitive diaphragm; one end of the optical fiber is fixedly arranged in the central through hole and is packaged through a packaging sleeve fixed at the top of the packaging cover plate; the optical fiber end face and the sensitive diaphragm form a resonant cavity. According to the invention, temperature and vibration signals can be monitored synchronously under a high-temperature condition, self-calibration of the vibration signals is realized, and the measurement precision is improved.

Description

Technical Field

[0001] The invention belongs to the field of high temperature sensing, and in particular relates to a self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor. Background Art

[0002] With the rapid development of aerospace technology, solid rocket engines have shown broad application prospects in many key fields such as space transportation and missile launches due to their simple structure and high reliability. However, the combustion chamber of solid rocket engines is often accompanied by incomplete fuel combustion during the combustion process, and produces problems such as high temperature, high pressure and strong vibration, causing irreversible damage to the engine structure and even causing serious safety accidents. At present, traditional silicon-based electrical sensors are difficult to work normally in harsh environments such as high temperature and strong corrosion, which greatly limits their application in solid rocket engine monitoring.

[0003] Fiber optic sensors have the advantages of anti-electromagnetic interference, intrinsic safety, and corrosion resistance, and are widely used in extremely harsh environments. Among them, sensors made of fiber Bragg gratings can achieve accurate measurement of different physical quantities, and have the advantages of a wide range of applications, high measurement resolution, and a large number of measurable physical quantities. Fiber Bragg grating sensors have developed rapidly in the past few decades and have been applied to many fields such as bridge monitoring, aerospace, and petrochemicals. In actual applications, temperature and vibration are two important physical parameters, and their changes can often directly reflect the state and safety of objects. However, at this stage, fiber Bragg grating sensors can often only achieve single parameter measurement at a certain point, and cannot achieve simultaneous measurement of temperature and vibration. This limitation greatly limits the application scope of fiber Bragg grating sensors in complex environments, so that when it is necessary to monitor temperature and vibration at the same time, multiple sensors have to be used for separate measurements, which not only increases the complexity and cost of the system, but also may cause large errors in the measurement results due to the mutual influence between sensors.

[0004] In addition, generally speaking, fiber Bragg grating vibrometers have the advantages of good stability and consistency, but they have problems such as high cross-sensitivity and thermal mismatch at the connection with the cantilever beam at high temperatures; while Fabry-Perot cavity vibrometers have poor stability and consistency, but they have low cross-sensitivity, almost no thermal mismatch problems, and higher temperature resistance. Summary of the invention

[0005] In order to overcome the difficulty in the prior art that optical fiber sensors are difficult to synchronously and accurately obtain temperature and vibration signals in high-temperature harsh environments, the present invention proposes a self-calibrated high-temperature resistant optical fiber temperature-vibration dual-parameter sensor to achieve accurate measurement of temperature and vibration signals in harsh environments such as high temperature and strong vibration.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a self-calibration high temperature resistant optical fiber temperature-vibration dual parameter sensor, comprising: a packaging base, a packaging cover, a packaging sleeve, an optical fiber, a Bragg fiber grating, and a sensitive diaphragm;

[0007] The packaging cover is fixedly connected to the packaging base, a first diaphragm groove is provided on the top of the packaging base, a second diaphragm groove is provided on the bottom of the packaging cover, the first diaphragm groove and the second diaphragm groove are arranged oppositely to form a vibration space of the sensitive diaphragm; a central through hole is provided on the packaging cover at the center of the second diaphragm groove;

[0008] The sensitive diaphragm comprises a bracket, a cantilever beam and a mass block connected in sequence, the bracket is fixedly connected to the packaging cover plate, the mass block is arranged in the vibration space, the Bragg fiber grating is provided with a first Bragg grating and a second Bragg grating with different central wavelengths, the first Bragg grating is fixed on the packaging cover plate, and the second Bragg grating is fixedly arranged on the sensitive diaphragm;

[0009] One end of the optical fiber is fixedly arranged in the central through hole and is packaged by a packaging sleeve fixed on the top of the packaging cover plate; the optical fiber end face and the sensitive membrane form a resonant cavity.

[0010] The self-calibration high temperature resistant optical fiber temperature-vibration dual parameter sensor also includes a hollow tube, one end of the optical fiber is fixed in the hollow tube by high temperature inorganic glue; the hollow tube is fixed in the central through hole of the packaging cover plate by high temperature inorganic glue.

[0011] The packaging base, packaging cover plate and packaging sleeve are made of stainless steel, and the optical fiber, Bragg fiber grating, sensitive membrane and hollow tube are made of sapphire.

[0012] The self-calibration high-temperature resistant optical fiber temperature-vibration dual-parameter sensor also includes a packaging base, which is fixed to the bottom of the packaging base and fixedly connected to the packaging base and the packaging cover by bolts. A mounting threaded hole for connecting a test component is provided at the center of the bottom of the packaging base.

[0013] The wavelength of the first Bragg grating is 1545 nm, the wavelength of the second Bragg grating is 1550 nm, the first Bragg grating is fixed to the sensitive film by high-temperature inorganic glue, and the second Bragg grating is fixed to the packaging cover by high-temperature inorganic glue.

[0014] The tail end of the Bragg fiber grating located in the vibration space is provided with a spherical fiber part.

[0015] The sensitive membrane is a single cantilever beam structure, and a sink connected to the second membrane groove is also provided at the bottom of the packaging cover plate. The sink is used to fix the bracket and further fix the sensitive membrane.

[0016] The mass block, the first diaphragm slot and the second diaphragm slot are all square, and the bracket is an isosceles triangle. One end of the cantilever beam is connected to the top corner of the bracket, and the other end is connected to one of the corners of the mass block.

[0017] The packaging cover plate is provided with a plurality of fourth threaded holes, and the packaging cover plate is fixedly connected to the packaging base via bolts arranged in the fourth threaded holes; the packaging sleeve is provided with a plurality of fifth through holes, and the packaging sleeve is fixedly connected to the packaging cover plate and the packaging base via bolts arranged in the fifth through holes.

[0018] The self-calibration high temperature resistant optical fiber temperature-vibration dual parameter sensor further comprises a first optical fiber armored tube and a second optical fiber armored tube;

[0019] The first optical fiber armor tube is arranged on the packaging sleeve, and the packaging sleeve is provided with a sixth threaded hole, and the sixth threaded hole is used to set a bolt to fix the first optical fiber armor tube, and the first optical fiber armor tube is used to protect the optical fiber;

[0020] The second optical fiber armored tube is arranged between the packaging base and the packaging cover plate, and a fifth threaded hole is arranged on the packaging cover plate. The fifth threaded hole is used to set a bolt to fix the second optical fiber armored tube, and the second optical fiber armored tube is used to protect the Bragg fiber grating.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides a self-calibrating high-temperature resistant optical fiber temperature-vibration dual-parameter sensor, which uses Bragg gratings with two sets of different central wavelengths to achieve dual-parameter measurement of temperature and vibration; wherein the first Bragg grating is fixed on the surface of the packaging cover plate, is only sensitive to temperature, and detects the actual temperature change by observing the drift of its central wavelength; meanwhile, the second Bragg grating is fixed on the surface of the sapphire sensitive diaphragm, is sensitive to both vibration and temperature, and detects the superposition change of actual temperature and vibration by measuring the drift of its central wavelength; meanwhile, the central wavelength drift of the first Bragg grating is used to calibrate the central wavelength drift of the second Bragg grating, eliminates the influence of temperature change on the central wavelength of the second Bragg grating, and can simultaneously solve the size of the temperature and vibration signals in the environment, and the consistency of the measurement data is strong.

[0023] 2. Moreover, the sensor of the present invention is also provided with a vibration sensor formed by a Fabry-Perot cavity, which forms a Fabry-Perot resonant cavity between a sapphire optical fiber and a sapphire sensitive diaphragm, and the magnitude of the vibration signal can be obtained by demodulating the interference light signal output by the cavity. The present invention simultaneously measures the vibration signal of the same sensitive unit through the fiber grating and the Fabry-Perot cavity, and uses two vibration signals to simultaneously characterize the vibration, which can reduce the error caused by the randomness of the single data, thereby solving the problems of high cross sensitivity of the fiber grating vibration sensor, thermal mismatch at high temperature, and poor stability and consistency of the Fabry-Perot cavity vibration sensor, and improving the accuracy of the measurement data through self-calibration. Specifically, a more accurate measurement result can be obtained by taking the average value of the two signals.

[0024] 3. In the present invention, the sensor forms a packaging shell through a packaging base, a packaging cover plate, and a packaging sleeve. The packaging shells are all made of 310S stainless steel material, which realizes a fully rigid connection between the packages, ensures the stability of the optical sensing signal of the sensor under different temperatures and vibrations, and improves the test accuracy of the sensor in a high temperature environment. Moreover, the working area of ​​the sensor is completely composed of sapphire material, forming a homogeneous integration of sapphire material, which can achieve stable sensing performance in a high temperature environment and prevent the problem of thermal effect mismatch due to different thermal expansion coefficients of the materials.

[0025] In summary, the present invention proposes an optical fiber sensor with integrated dual parameters of temperature and vibration, which can not only realize the synchronous monitoring of temperature and vibration signals, but also simultaneously measure the vibration signals of the same sensitive unit through the Fabry-Perot cavity, thereby realizing self-calibration of vibration signals, improving the consistency and accuracy of measurement data, and breaking through the operating temperature limit of traditional sensors. It can not only realize the synchronous acquisition of temperature and vibration signals of the combustion field of solid rocket engines, but also broaden the operating frequency band of the sensor, and has practical application value in high temperature and strong vibration environments in the fields of aerospace, missile launch, and non-destructive testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A cross-sectional schematic diagram of a high temperature resistant optical fiber temperature-vibration dual parameter sensor with a self-calibration function provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the three-dimensional structure of a high-temperature resistant optical fiber temperature-vibration dual-parameter sensor with a self-calibration function provided by an embodiment of the present invention;

[0028] Figure 3 It is a three-dimensional assembly diagram of a packaging cover plate, a sapphire sensitive membrane, and a sapphire Bragg grating in an embodiment of the present invention;

[0029] Figure 4is a schematic diagram of the cross-sectional structure of a packaging substrate in an embodiment of the present invention;

[0030] Figure 5 It is a schematic diagram of the three-dimensional structure of the packaging base in an embodiment of the present invention;

[0031] Figure 6 is a schematic diagram of the three-dimensional structure of the packaging cover plate in an embodiment of the present invention;

[0032] Figure 7 It is a schematic diagram of the three-dimensional structure of the packaging sleeve in an embodiment of the present invention;

[0033] Figure 8 Schematic diagram of the three-dimensional structure of a sapphire sensitive membrane in an embodiment of the present invention;

[0034] Fig. 9 Schematic diagram of the reflection spectrum of the Bragg grating optical fiber in an embodiment of the present invention;

[0035] Fig.10 Schematic diagram of the reflection spectrum of the Fabry-Perot cavity in an embodiment of the present invention;

[0036] In the figure: 2-packaging base, 3-packaging cover, 4-packaging sleeve, 5-first optical fiber armored tube, 6-optical fiber, 7-second optical fiber armored tube, 8-Bragg fiber grating, 9-hollow tube, 10-sensitive diaphragm, 11-packaging base, 21-second threaded hole, 22-first long groove, 23-first diaphragm groove, 24-fifth through hole, 25-first through hole, 31-first threaded hole, 32-fourth through hole, 33-fourth threaded hole, 34-third through hole, 35-second long groove, 36-third long groove, 37-sunk groove, 38-second diaphragm groove, 39-center through hole, 41-second through hole, 42-circular groove, 43-third threaded hole, 81-first Bragg grating, 82-second Bragg grating, 83-spherical optical fiber, 101-bracket, 102-single cantilever beam, 103-mass block, 111-mounting threaded hole, 112-fifth threaded hole. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] like Figures 1 to 8As shown, an embodiment of the present invention provides a high temperature resistant optical fiber temperature-vibration dual parameter sensor with self-calibration function, including a packaging base 2, a packaging cover 3, a packaging sleeve 4, an optical fiber 6, a Bragg fiber grating 8, and a sensitive diaphragm 10.

[0039] The package cover plate 3 is fixedly connected to the package base 2, a first diaphragm groove 23 is formed on the top of the package base 2 by etching, a second diaphragm groove 38 is formed on the bottom of the package cover plate 3 by etching, the first diaphragm groove 23 and the second diaphragm groove 38 are arranged opposite to each other to form a vibration space of the sensitive diaphragm 10; a central through hole 39 located at the center of the second diaphragm groove 38 is provided on the package cover plate 3;

[0040] The sensitive diaphragm 10 comprises a bracket 101, a cantilever beam 102 and a mass block 103 connected in sequence, the bracket 101 is fixedly connected to the packaging cover plate 3, the mass block 103 is arranged in the vibration space, the Bragg fiber grating 8 is provided with a first Bragg grating 81 and a second Bragg grating 82 with different central wavelengths, the first Bragg grating 81 is fixed on the packaging cover plate 3, and the second Bragg grating 82 is fixedly arranged on the sensitive diaphragm 10.

[0041] One end of the optical fiber 6 is fixedly disposed in the central through hole 39 and is packaged by a packaging sleeve 4 fixed on the top of the packaging cover plate 3 ; the end face of the optical fiber 6 and the sensitive membrane 10 form a resonant cavity.

[0042] Furthermore, a self-calibration high-temperature resistant optical fiber temperature-vibration dual-parameter sensor of the present embodiment also includes a hollow tube 9, one end of the optical fiber 6 is fixed in the hollow tube 9 by high-temperature inorganic glue; the hollow tube 9 is fixed in the central through hole 39 of the packaging cover plate 3 by high-temperature inorganic glue.

[0043] In this embodiment, the packaging base 2, the packaging cover plate 3, and the packaging sleeve 4 are made of stainless steel, and the optical fiber 6, the Bragg fiber grating 8, and the sensitive membrane 10 are made of sapphire.

[0044] Furthermore, the self-calibration high temperature resistant optical fiber temperature-vibration dual parameter sensor of this embodiment further includes a packaging substrate 11, the packaging substrate 11 is fixed to the bottom of the packaging base 2, and the packaging base 2 and the packaging cover 3 are fixed on the packaging substrate 11 by bolts. Figure 8As shown, a mounting threaded hole 111 for connecting the test component is provided at the center of the bottom of the packaging substrate 11. By providing the packaging substrate 11, when installing the sensor, the packaging substrate 11 can be first connected to the component to be tested by means of screws in the mounting threaded hole 111, and then bolts can be passed through the packaging cover plate 3 and the packaging base 2 and then connected to the packaging substrate 11 to fix the sensor, thereby avoiding damage to the optical fiber caused by the rotation process when installing the sensor.

[0045] Specifically, in this embodiment, the wavelength of the first Bragg grating 81 is 1545nm, the wavelength of the second Bragg grating 82 is 1550nm, the first Bragg grating 81 is fixed to the sensitive film 10 by high-temperature inorganic glue, and the second Bragg grating 82 is fixed to the packaging cover plate 3 by high-temperature inorganic glue. Specifically, the first Bragg grating 81 and the second Bragg grating 82 can be formed by writing inside the optical fiber by a femtosecond laser. Among them, the first Bragg grating 81 is pasted on the surface of the packaging cover plate 3, which is only sensitive to temperature. The actual temperature change is detected by observing the drift of its central wavelength. At the same time, the second Bragg grating 82 is pasted on the surface of the sapphire sensitive film 10, which is sensitive to both vibration and temperature. The actual temperature and vibration superposition changes are detected by observing the drift of its central wavelength. By using the first Bragg grating 81 to compensate the second Bragg grating 82, the temperature and vibration signals in the environment can be solved at the same time.

[0046] Furthermore, in this embodiment, the tail end of the Bragg fiber grating 8 located in the vibration space is provided with a spherical fiber portion 83. Specifically, the tail end of the Bragg fiber grating 8 is sintered using a fiber fusion splicer to form a spherical fiber 83. The spherical fiber 83 formed by sintering can effectively increase the return loss and improve the spectral signal-to-noise ratio.

[0047] Furthermore, if Figure 3 and 7 As shown, in this embodiment, the sensitive membrane 10 is a single cantilever beam structure, and the bracket 101 is connected to the mass block 103 through a cantilever beam 102. Figure 5 As shown, the bottom of the package cover plate 3 is also provided with a sinking groove 37 connected to the second diaphragm groove 38, and the sinking groove 37 is used to fix the bracket 101, and then fix the sensitive diaphragm 10. The depth of the sinking groove 37 is less than the second diaphragm groove 38, so the gap between the second diaphragm groove 38 and the mass block 103 forms an upward vibration space for the mass block 103 of the sensitive diaphragm 10. In addition, the gap between the first diaphragm groove 23 at the top of the package base 2 and the mass block 103 forms a downward vibration space for the mass block 103 of the sensitive diaphragm 10.

[0048] Further, in this embodiment, the mass block 103, the first diaphragm slot 23 and the second diaphragm slot 38 are all square, and the bracket 101 is an isosceles triangle, one end of the cantilever beam 102 is connected to the top corner of the bracket 101, and the other end is connected to one of the corners of the mass block 103. In addition, the mass block 103 and the first diaphragm slot 23 and the second diaphragm slot 38 are staggered at 45 degrees, and the side lengths of the first diaphragm slot 23 and the second diaphragm slot 38 are greater than the diagonal length of the square mass block 103.

[0049] Further, in this embodiment, a plurality of first threaded holes 31 are provided on the packaging cover plate 3, a first through hole 25 is provided on the packaging base 2 at a position corresponding to the first threaded hole 31, and the packaging base 2 is fixedly connected to the packaging cover plate 3 by bolts arranged in the first through hole 25 and the first threaded hole 31; a plurality of second through holes 41 are provided on the packaging sleeve 4, a third through hole 34 is provided on the packaging cover plate 3 at a position corresponding to the second through hole 41, a second threaded hole 21 is provided on the packaging base 2 at a position corresponding to the second through hole 41, and the bolts arranged in the second through hole 41, the third through hole 34 and the second threaded hole 21 fix the packaging sleeve 4 to the packaging cover plate 3 and the packaging base 2 together.

[0050] Furthermore, if Figures 1-2 As shown, a self-calibration high-temperature resistant optical fiber temperature-vibration dual-parameter sensor of the present embodiment also includes a first optical fiber armored tube 5 and a second optical fiber armored tube 7; the first optical fiber armored tube 5 is arranged on the packaging sleeve 4, and the packaging sleeve 4 is provided with two third threaded holes 43, and the third threaded holes 43 are used to set bolts to fix the first optical fiber armored tube 5, and the first optical fiber armored tube 5 is used to protect the optical fiber 6; the second optical fiber armored tube 7 is arranged between the packaging base 2 and the packaging cover plate 3, and the packaging cover plate 3 is provided with two fourth threaded holes 33, and the fourth threaded holes 33 are used to set bolts to fix the second optical fiber armored tube 7, and the second optical fiber armored tube 7 is used to protect the Bragg fiber grating 8.

[0051] Furthermore, in this embodiment, a plurality of fourth through holes 32 are provided on the packaging cover plate 3, a fifth through hole 24 is provided on the packaging base 2 at a position corresponding to the fourth through hole 32, and a fifth threaded hole 112 is provided on the packaging substrate 11 at a position corresponding to the fourth through hole 32. The bolts provided in the fourth through hole 32, the fifth through hole 24 and the fifth threaded hole 112 fix the packaging cover plate 3, the packaging base 2 and the packaging substrate 11 together.

[0052] Furthermore, in the present embodiment, the first long groove 22 and the second long groove 35 are respectively provided on the packaging base 2 and the packaging cover plate 3 at positions corresponding to the second optical fiber armored tube 7, and the first long groove 22 and the second long groove 35 form a accommodating space for the second optical fiber armored tube 7; further, in addition, a third long groove 36 is provided between the second long groove 35 and the sinking groove 37, and the third long groove 36 is used to set the optical fiber segment where the first Bragg grating of the Bragg fiber grating 8 is located.

[0053] Furthermore, in this embodiment, the packaging sleeve 4 includes a flat plate portion and a top protrusion, the second through hole 41 is provided on the flat plate portion, the third threaded hole 43 is provided on the top protrusion, and a circular groove 42 is provided inside the top protrusion for accommodating the hollow tube 9.

[0054] In addition, an embodiment of the present invention also provides an assembly method of the high temperature resistant optical fiber temperature-vibration dual parameter sensor with self-calibration function, comprising the following steps:

[0055] Step S1: placing the pre-cleaned sensitive film 10 on the packaging cover plate 3, and evenly applying high-temperature inorganic glue between the packaging cover plate 3 and the sensitive film 10, and curing the high-temperature inorganic glue by baking in an oven.

[0056] Step S2: Place the Bragg fiber grating 8 engraved by femtosecond laser on the packaging cover plate 3 and the sapphire sensitive film 10, and use a full-adhesion method to evenly apply high-temperature inorganic glue at the position where the Bragg fiber grating 8 contacts the packaging cover plate 3 and the sensitive film 10, and cure the high-temperature inorganic glue by baking in an oven.

[0057] Step S3: Use screws to tightly connect the packaging cover plate 3 and the packaging base 2.

[0058] Step S4: Insert the head of the optical fiber 6 wrapped by the hollow tube 9 into the central through hole 39 of the packaging cover plate 3, evenly apply high-temperature inorganic glue on the connection between the packaging cover plate 3 and the sapphire hollow tube 9, and cure the high-temperature inorganic glue by baking in an oven.

[0059] Step S5: Use screws to tightly connect the packaging sleeve 4, the packaging cover plate 3 and the packaging base 2.

[0060] Step S6: Use screws to place the package substrate on the component to be tested, and then pass the screws through the package cover plate 3 and the package base 2 to be tightly connected to the package substrate 11 .

[0061] Specifically, in this embodiment, step S3 further includes the following steps:

[0062] The second optical fiber armor tube 7 is passed through the outer side of the Bragg fiber grating 8 and extends into the first long groove 22 and the second long groove 35 of the packaging cover plate 3 and the packaging base 2, and the second optical fiber armor tube 7 is fixed by screws arranged in the plurality of fourth threaded holes 33;

[0063] The step S5 further comprises the following steps:

[0064] The first optical fiber armor tube 5 is passed through the outer side of the optical fiber 6 and extends into the packaging sleeve 4, and the second optical fiber armor tube 7 is fixed by screws arranged at a plurality of third threaded holes 43.

[0065] In this embodiment, the amplified spontaneous radiation light source enters the Bragg fiber grating 8 through the fiber circulator, and the reflected light generated by the grating area enters the spectrometer through the fiber circulator. The obtained spectral signal is as follows: Fig. 9 As shown, by demodulating the jitter of the reflection spectrum of the second Bragg grating 82 near its central wavelength, a vibration signal can be obtained.

[0066] In this embodiment, the amplified spontaneous radiation light source enters the optical fiber 6 through the optical fiber circulator, and multi-beam interference occurs between the end face of the optical fiber 6 and the surface of the sensitive film 10. The interference light enters the spectrometer through the optical fiber circulator, and the obtained spectral signal is as follows: Fig.10 As shown, by collecting the changes in the free spectrum region of the spectrum over time, the demodulation of the vibration signal can be achieved.

[0067] In summary, the present invention proposes a self-calibrated high-temperature resistant optical fiber temperature-vibration dual-parameter sensor, which realizes the synchronous measurement of the dual parameters of temperature and vibration by observing the drift of the central wavelength of two groups of Bragg gratings with different central wavelengths. Moreover, in the present invention, a Fabry-Perot resonant cavity is formed by a sensitive diaphragm and a sapphire optical fiber to calibrate the vibration signal and improve the test range and accuracy. In addition, in the present invention, the packaging shell is rigidly connected by stainless steel to ensure the stability of the optical sensing signal of the sensor under different temperatures and vibrations, improve the test accuracy of the sensor in a high-temperature environment, break through the operating temperature limit of traditional sensors, broaden the operating frequency band of the sensor, and have practical application value in high-temperature and strong vibration environments in the fields of aerospace, missile launch, and non-destructive testing.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor, characterized in that: include: A packaging base (2), a packaging cover plate (3), a packaging sleeve (4), an optical fiber (6), a Bragg fiber grating (8), and a sensitive membrane (10); The packaging cover plate (3) is fixedly connected to the packaging base (2); a first diaphragm groove (23) is provided on the top of the packaging base (2); a second diaphragm groove (38) is provided on the bottom of the packaging cover plate (3); the first diaphragm groove (23) and the second diaphragm groove (38) are arranged opposite to each other to form a vibration space of the sensitive diaphragm (10); and a central through hole (39) located at the center of the second diaphragm groove (38) is provided on the packaging cover plate (3); The sensitive diaphragm (10) comprises a bracket (101), a cantilever beam (102) and a mass block (103) connected in sequence, the bracket (101) is fixedly connected to the packaging cover plate (3), the mass block (103) is arranged in a vibration space, the Bragg fiber grating (8) is provided with a first Bragg grating (81) and a second Bragg grating (82) having different central wavelengths, the first Bragg grating (81) is fixed on the packaging cover plate (3), and the second Bragg grating (82) is fixedly arranged on the sensitive diaphragm (10); One end of the optical fiber (6) is fixedly arranged in the central through hole (39) and is packaged by a packaging sleeve (4) fixed on the top of the packaging cover plate (3); the end face of the optical fiber (6) and the sensitive membrane (10) form a resonant cavity.

2. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 1, characterized in that: It also includes a hollow tube (9), one end of the optical fiber (6) is fixed in the hollow tube (9) by means of high-temperature inorganic glue; the hollow tube (9) is fixed in the central through hole (39) of the packaging cover plate (3) by means of high-temperature inorganic glue.

3. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 2, characterized in that: The packaging base (2), the packaging cover plate (3), and the packaging sleeve (4) are made of stainless steel, and the optical fiber (6), the Bragg fiber grating (8), the sensitive membrane (10), and the hollow tube (9) are made of sapphire.

4. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 1, characterized in that: It also comprises a packaging base (11), the packaging base (11) being fixed to the bottom of the packaging base (2), and being fixedly connected to the packaging base (2) and the packaging cover plate (3) by means of bolts, and a mounting threaded hole (111) for connecting a test component is provided at the center of the bottom of the packaging base (11).

5. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 1, characterized in that: The wavelength of the first Bragg grating (81) is 1545 nm, the wavelength of the second Bragg grating (82) is 1550 nm, the first Bragg grating (81) is fixed to the sensitive film (10) by means of high-temperature inorganic glue, and the second Bragg grating (82) is fixed to the packaging cover plate (3) by means of high-temperature inorganic glue.

6. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 1, characterized in that: A spherical optical fiber portion (83) is provided at the tail end of the Bragg fiber grating (8) located in the vibration space.

7. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 1, characterized in that: The sensitive diaphragm (10) is a single cantilever beam structure, and a sink groove (37) connected to the second diaphragm groove (38) is also provided at the bottom of the packaging cover plate (3), and the sink groove (37) is used to fix the bracket (101) and further fix the sensitive diaphragm (10).

8. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 7, characterized in that: The mass block (103), the first diaphragm slot (23) and the second diaphragm slot (38) are all square, and the bracket (101) is an isosceles triangle. One end of the cantilever beam (102) is connected to the top corner of the bracket (101), and the other end is connected to one of the corners of the mass block (103).

9. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 6, characterized in that: The packaging cover plate (3) is provided with a plurality of fourth threaded holes (31), and the packaging cover plate (3) is fixedly connected to the packaging base (2) via bolts arranged in the fourth threaded holes (31); the packaging sleeve (4) is provided with a plurality of fifth through holes (41), and the packaging sleeve (4) is fixedly connected to the packaging cover plate (3) and the packaging base (2) via bolts arranged in the fifth through holes (41).

10. The self-calibrating high temperature resistant optical fiber temperature-vibration dual parameter sensor according to claim 6, characterized in that: It also includes a first optical fiber armored tube (5) and a second optical fiber armored tube (7); The first optical fiber armored tube (5) is arranged on the packaging sleeve (4), and a sixth threaded hole (43) is arranged on the packaging sleeve (4). The sixth threaded hole (43) is used to set a bolt to fix the first optical fiber armored tube (5), and the first optical fiber armored tube (5) is used to protect the optical fiber (6); The second optical fiber armored tube (7) is arranged between the packaging base (2) and the packaging cover plate (3); a fifth threaded hole (33) is arranged on the packaging cover plate (3); the fifth threaded hole (33) is used to set a bolt to fix the second optical fiber armored tube (7); the second optical fiber armored tube (7) is used to protect the Bragg fiber grating (8).

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