Optical fiber cranium temperature and cranium pressure composite monitoring probe and preparation method thereof

Abstract

The invention relates to the technical field of optical fiber sensors, and provides an optical fiber cranium temperature and cranium pressure composite monitoring probe and a preparation method thereof.The optical fiber cranium temperature and cranium pressure composite monitoring probe comprises a pressure diaphragm, a hollow glass tube, a metal coating, a graded-index optical fiber and a single-mode optical fiber, one end of the hollow glass tube is connected with the pressure diaphragm; the metal coating is arranged on one surface, far away from the hollow glass tube, of the pressure diaphragm; the graded-index optical fiber is arranged in the hollow glass tube, and the graded-index optical fiber and the pressure diaphragm are spaced to form an F-P cavity; and one end of the single-mode optical fiber is inserted into the hollow glass tube. The corrugated pressure diaphragm formed by processing the coreless optical fiber is used as a sensitive element, the pressure measurement sensitivity can be greatly improved under the condition of the same diaphragm thickness and diameter, the zero drift of the sensor caused by temperature and moisture is reduced, and meanwhile, the pressure sensitivity can be accurately regulated and controlled so as to adapt to different application scenes such as intracranial pressure, intramental pressure and blood flow pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensors, and in particular to an optical fiber cranial temperature and pressure composite monitoring probe and a preparation method thereof. Background Art

[0002] Monitoring the temperature and pressure of the human body's internal environment, such as the brain, blood vessels, and kidneys, is a key indicator for medical health assessment. Fiber optic sensors, with their small size, high precision, high sensitivity, strong anti-electromagnetic interference ability, and good biocompatibility, can accurately monitor human body temperature and pressure in complex medical environments. Existing internal environment monitoring systems still have the problem of single measurement parameters. Fiber optic temperature and pressure composite sensors can achieve multi-parameter measurement of temperature and pressure, and have significant advantages and broad application prospects in monitoring the temperature and pressure of the human body's internal environment.

[0003] The existing patent application with international publication number WO2021052123A1 discloses a micro-diaphragm-type optical fiber end face FP pressure sensor and its manufacturing method and application. The micro-optical fiber end face FP pressure sensor includes an optical fiber, a hollow-core optical fiber and a pressure-sensitive diaphragm. The optical fiber and the hollow-core optical fiber have the same diameter, and the two are arc welded. The pressure-sensitive diaphragm is bonded to the end face of the hollow-core optical fiber by a hydrogen-oxygen catalytic bonding method.

[0004] For example, the sensor in the above technical solution uses a flat diaphragm. This type of sensor usually increases or decreases the thickness to improve the pressure sensitivity of the diaphragm. However, the strict requirements of intrusive pressure sensing on the tiny size of the sensor limit the diameter of the diaphragm. At the same time, the machining accuracy also restricts the further reduction of the diaphragm thickness.

[0005] The zero-point drift of the pressure sensor caused by the slow release of the mechanical stress of the diaphragm is a key factor restricting the pressure measurement sensitivity; the low beam coupling efficiency of the traditional FP cavity results in low interference spectrum contrast, which also restricts the demodulation resolution of the FP cavity length. Summary of the invention

[0006] In view of this, the present invention proposes an optical fiber cranial temperature and pressure composite monitoring probe with high pressure sensitivity and high spectral contrast, which can effectively improve the pressure measurement resolution, and a preparation method thereof, so as to solve the problem that the sensitivity of the existing sensor diaphragm cannot be improved due to processing factors.

[0007] The technical solution of the present invention is achieved in this way:

[0008] On the one hand, the present invention provides an optical fiber cranial temperature and pressure composite monitoring probe, comprising a pressure diaphragm, a hollow glass tube, a metal coating, a gradient refractive index optical fiber and a single-mode optical fiber, wherein:

[0009] The pressure diaphragm is in a corrugated shape, and the corrugated shape is rectangular or sinusoidal;

[0010] One end of the hollow glass tube is connected to the pressure diaphragm;

[0011] The metal coating is arranged on a side of the pressure diaphragm away from the hollow glass tube;

[0012] The graded refractive index optical fiber is arranged in the hollow glass tube, and the graded refractive index optical fiber is spaced apart from the pressure diaphragm to form an FP cavity, and the pressure diaphragm has a protruding plane portion corresponding to the collimated light beam;

[0013] One end of the single-mode optical fiber is inserted into a hollow glass tube and connected to a graded-refractive-index optical fiber, on which a fiber grating is engraved.

[0014] On the basis of the above technical solution, preferably, the diameter ratio of the single-mode optical fiber to the graded-refractive-index optical fiber is 1:1.

[0015] On the basis of the above technical solution, preferably, it also includes a reed switch, a metal capillary, glue and a probe front end, wherein:

[0016] The reed pipe is a hollow structure;

[0017] The metal capillary is arranged in the soft reed tube and fixed by glue;

[0018] The optical fiber cranial temperature and pressure composite monitoring probe is integrated in the metal capillary;

[0019] The front end of the probe is arranged at the end of the reed tube, and the end of the front end of the probe is arranged as a hemispherical shell structure.

[0020] On the basis of the above technical solution, preferably, the relationship between the deformation displacement of the corrugated pressure diaphragm and the load P is:

[0021]

[0022] in,

[0023]

[0024] Wherein, E is the elastic modulus of the pressure diaphragm; v is the Poisson's ratio of the pressure diaphragm; h is the thickness of the pressure diaphragm; d is the radius of the pressure diaphragm; q is the pressure diaphragm profile coefficient, which is used to measure the pressure diaphragm profile; It represents the ratio of the actual distance from the center to the edge of the pressure diaphragm measured along the corrugation profile to its radius; H is the corrugation depth; L is the corrugation width; S is the corrugation arc length; N is the number of corrugation cycles; ΔX is the deformation displacement of the corrugated diaphragm; K p is the temperature in the FP chamber (101); J p is the formula coefficient.

[0025] On the basis of the above technical solution, preferably, when the pressure diaphragm is deformed by a large initial stress, its initial stress σ 0 The relationship between the load P and the diaphragm deformation displacement is:

[0026]

[0027] The corrugated diaphragm is designed to The load P and displacement ΔX are approximately linearly related. From the above formula, it can be seen that when subjected to a large initial stress, the lateral deformation of the corrugated diaphragm reduces its axial displacement by Times, perform linear superposition on the above formula, and only consider the linear part to simplify the calculation, as shown below:

[0028]

[0029] From the above formula, the expression of the pressure diaphragm deformation displacement ΔX can be obtained as follows:

[0030]

[0031] On the basis of the above technical solution, preferably, the material of the metal plating layer is one of gold, silver, nickel and copper, and the theoretical expression of the FP cavity interference spectrum is:

[0032]

[0033] Among them, R 1 is the reflectivity of the graded-index fiber end face, R 2 is the reflectivity of the inner surface of the pressure diaphragm, R 3 is the surface reflectivity of the metal coating, η 1 , η 2 , η 3 is the intensity loss coefficient of the light beam at the end face of the graded refractive index optical fiber, the inner surface of the pressure diaphragm, and the surface of the metal coating; is the phase difference generated when the light beam passes through the FP cavity interference, It is the phase difference generated when the light beam passes through the inner and outer surfaces of the pressure diaphragm.

[0034] On the basis of the above technical solution, preferably, the gradient refractive index optical fiber is fused with the single-mode optical fiber to shape and collimate the light beam emitted and received by the single-mode optical fiber. The length of the gradient refractive index optical fiber is calculated according to the following formula:

[0035]

[0036] in, D SMF is the core diameter of single-mode optical fiber, D GIFis the core diameter of the graded-index fiber, λ is the central wavelength of the light source, and NA is the numerical aperture of the graded-index fiber.

[0037] On the basis of the above technical solutions, preferably, the fiber Bragg grating on the single-mode optical fiber is used for temperature sensing and temperature compensation of the FP cavity, and the temperature pressure demodulation measurement matrix is:

[0038]

[0039] In the formula, k t is the temperature of the FP cavity; k p is the pressure measurement sensitivity of the FP cavity, k f is the temperature sensitivity of the fiber Bragg grating, Δλ is the wavelength drift, and ΔL is the FP cavity change.

[0040] On the other hand, the present invention provides a probe preparation method for preparing the above-mentioned optical fiber cranial temperature and pressure composite monitoring probe, comprising the following steps:

[0041] S1. Using a femtosecond laser to write on the end face of a coreless optical fiber according to the designed corrugation shape parameters;

[0042] S2, using arc welding technology to weld the coreless optical fiber and the hollow glass tube, and cutting the hollow glass tube to a suitable length;

[0043] S3, using arc welding technology to weld the single-mode optical fiber engraved with the fiber grating and the graded refractive index optical fiber;

[0044] S4. Cut the graded-index optical fiber to a suitable length using an optical fiber cutter under a microscope;

[0045] S5. After the end face of the single-mode optical fiber is polished, it is inserted into the hollow glass tube using the optical fiber fusion splicing platform. Then, the feeding amount of the fusion splicing platform is adjusted to control the insertion process of the single-mode optical fiber. At the same time, the length of the formed FP cavity is monitored by the FP cavity white light interference demodulation algorithm. When the preset cavity length is reached and the interference spectrum contrast is good, the fusion splicing platform is controlled to discharge to fuse the single-mode optical fiber and the hollow glass tube.

[0046] S6. Using a fiber cleaver under a microscope, cut the coreless optical fiber to a length of 1 mm, and further reduce its length to less than 0.1 mm using a bare optical fiber grinder;

[0047] S7. Use femtosecond laser to further thin the length of the coreless optical fiber, and write grooves according to the preset waveform shape to form a pressure diaphragm. Finally, use chemical plating or measurement and control sputtering technology to coat the metal coating on the surface of the diaphragm to complete the preparation of the corrugated diaphragm FP cavity interventional optical fiber intracranial temperature and intracranial pressure composite monitoring probe.

[0048] Based on the above technical solution, preferably, all welding steps are carried out in a vacuum environment.

[0049] The optical fiber cranial temperature and pressure composite monitoring probe and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0050] (1) The present invention uses a corrugated pressure diaphragm made of coreless optical fiber as a sensitive element, which can greatly improve the pressure measurement sensitivity under the same diaphragm thickness and diameter, reduce the zero drift of the sensor caused by temperature and moisture, and the pressure sensitivity can be precisely controlled to adapt to different application scenarios such as intracranial pressure, intraneural pressure, and blood flow pressure;

[0051] (2) The present invention has a metal coating on the outer surface of the corrugated diaphragm, so that the light beam is diffusely reflected at the coating, thereby avoiding the influence of the change of the refractive index of the measuring medium on the reflection spectrum and the pressure measurement accuracy;

[0052] (3) The present invention shapes and collimates the light beam emitted and received by the single-mode optical fiber by connecting a graded refractive index optical fiber to the end of the single-mode optical fiber, thereby improving the light beam coupling efficiency of the FP, improving the contrast of the FP cavity interference spectrum, and further improving the cavity length demodulation resolution and the pressure measurement accuracy;

[0053] (4) The present invention uses a fiber Bragg grating and FP cavity cascade structure to achieve temperature and pressure decoupling measurement, thereby avoiding the influence of temperature changes on the FP cavity pressure measurement accuracy;

[0054] (5) The preparation process of the corrugated diaphragm optical fiber temperature and pressure sensor of the present invention is simple, low-cost, and can be mass-produced;

[0055] (6) The optical fiber composite monitoring probe for intracranial temperature and intracranial pressure used in the present invention has the advantages of small size and high flexibility and can be combined with a variety of medical devices. The optical fiber sensing technology used in the present invention has the characteristics of anti-electromagnetic interference. In the face of complex surgical environments, it can realize temperature and pressure monitoring throughout the entire surgical process and provide patients with better treatment strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 It is a structural diagram of the optical fiber cranial temperature and pressure composite monitoring probe of the present invention;

[0058] Figure 2 It is a structural diagram of the pressure diaphragm of the optical fiber composite monitoring probe for cranial temperature and pressure of the present invention;

[0059] Figure 3 This is a diagram showing the light beam alignment of the optical fiber composite cranial temperature and pressure monitoring probe of the present invention;

[0060] Figure 4 The present invention is a process flow chart for preparing the optical fiber composite cranial temperature and pressure monitoring probe;

[0061] Figure 5 It is a structural schematic diagram of the cranial cavity monitoring probe of the present invention;

[0062] In the figure: 1, pressure diaphragm; 11, plane part; 101, FP cavity; 2, hollow glass tube; 3, metal coating; 4, graded refractive index optical fiber; 5, single-mode optical fiber; 6, reed switch; 7, metal capillary; 8, glue; 9, probe tip;

[0063] 10. Fiber optic intracranial temperature and intracranial pressure composite monitoring probe. DETAILED DESCRIPTION

[0064] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] like Figures 1 to 3 As shown, the optical fiber intracranial temperature and intracranial pressure composite monitoring probe of the present invention includes a pressure diaphragm 1, a hollow glass tube 2, a metal coating 3, a gradient refractive index optical fiber 4, a single-mode optical fiber 5, a reed switch 6, a metal capillary 7, glue 8 and a probe front end 9.

[0066] like Figure 1 As shown, the pressure diaphragm 1 is in a corrugated shape, and the corrugated shape is rectangular or sinusoidal; one end of the hollow glass tube 2 is connected to the pressure diaphragm 1; the metal coating 3 is arranged on the side of the pressure diaphragm 1 away from the hollow glass tube 2; the graded refractive index optical fiber 4 is arranged in the hollow glass tube 2, and the graded refractive index optical fiber 4 is spaced from the pressure diaphragm 1 to form an FP cavity 101, and the pressure diaphragm 1 has a protruding plane portion 11 corresponding to the collimated light beam; one end of the single-mode optical fiber 5 is inserted into the hollow glass tube 2 and connected to the graded refractive index optical fiber 4, and the single-mode optical fiber 5 is engraved with a fiber grating;

[0067] As in the above structure, a FP cavity is formed between the pressure diaphragm 1 and the graded refractive index optical fiber 4 to detect the pressure, wherein the fiber Bragg grating on the single-mode optical fiber 5 is used for temperature sensing, and the temperature compensation of the FP cavity 101 is performed, and the temperature-pressure decoupling measurement is realized by using the cascade structure of the fiber Bragg grating and the FP cavity 101, thereby avoiding the influence of temperature change on the measurement accuracy of the FP cavity pressure;

[0068] The pressure diaphragm 1 is in a corrugated shape, which can reduce the processing stress in the diaphragm under the traditional grinding process, improve the pressure sensing sensitivity, and improve the zero drift during the use of the pressure sensor;

[0069] The metal coating 3 on the outer surface of the pressure diaphragm 1 causes the light beam to produce diffuse reflection at the coating, thereby avoiding the influence of the change of the refractive index of the measuring medium on the reflection spectrum and the pressure measurement accuracy;

[0070] Among them, by connecting the graded refractive index fiber 4 at the end of the single-mode optical fiber 5, the light beam emitted and received by the single-mode optical fiber 5 is shaped and collimated, thereby reducing the light beam propagation loss in the FP cavity, improving the light beam coupling efficiency of the FP cavity 101, improving the contrast of the interference spectrum of the FP cavity 101, and thus improving the cavity length demodulation resolution and the pressure measurement accuracy;

[0071] Among them, the pressure diaphragm 1 made of coreless optical fiber is used as a sensitive element, which can greatly improve the pressure measurement sensitivity under the same diaphragm thickness and diameter, reduce the zero drift of the sensor caused by temperature and moisture, and at the same time, the pressure sensitivity can be precisely controlled to adapt to different application scenarios such as intracranial pressure, intraneural pressure, and blood flow pressure.

[0072] The diameter ratio of the single-mode optical fiber to the graded-index optical fiber 4 is 1:1;

[0073] The relationship between the deformation displacement of the corrugated pressure diaphragm and the load P is:

[0074]

[0075] in,

[0076]

[0077] Wherein, E is the elastic modulus of the pressure diaphragm 1; v is the Poisson's ratio of the pressure diaphragm (1); h is the thickness of the pressure diaphragm 1; d is the radius of the pressure diaphragm 1; q is the profile coefficient of the pressure diaphragm 1, which is used to measure the profile of the pressure diaphragm 1; wherein It represents the ratio of the actual distance from the center to the edge of the pressure diaphragm 1 measured along the corrugation profile to its radius; H is the corrugation depth; L is the corrugation width; S is the corrugation arc length; N is the number of corrugation cycles; ΔX is the deformation displacement of the corrugated diaphragm; K pis the temperature in the FP chamber (101); J p is the formula coefficient.

[0078] When the pressure diaphragm 1 is deformed by a large initial stress, its initial stress σ 0 The relationship between the load P and the diaphragm deformation displacement is:

[0079]

[0080] The corrugated diaphragm 1 is designed to The load P and the displacement ΔX are approximately linearly related. From the above formula, it can be seen that when subjected to a large initial stress, the lateral deformation of the corrugated diaphragm 1 reduces its axial displacement by Times, perform linear superposition on the above formula, and only consider the linear part to simplify the calculation, as shown below:

[0081]

[0082] From the above formula, the expression of the deformation displacement ΔX of the pressure diaphragm 1 can be obtained as follows:

[0083]

[0084] The material of the metal plating layer 3 is one of gold, silver, nickel and copper. The theoretical expression of the interference spectrum of the FP cavity 101 is:

[0085]

[0086] Among them, R 1 is the reflectivity of the end face of the graded-index fiber 4, R 2 is the reflectivity of the inner surface of the pressure diaphragm 1, R 3 is the surface reflectivity of the metal coating 3, η 1 , η 2 , η 3 is the intensity loss coefficient of the light beam at the end face of the graded refractive index optical fiber 4, the inner surface of the pressure diaphragm 1, and the surface of the metal coating 3; is the phase difference generated when the light beam passes through the FP cavity 101, It is the phase difference generated when the light beam passes through the inner and outer surfaces of the pressure diaphragm 1.

[0087] The gradient refractive index optical fiber 4 is fused with the single-mode optical fiber 5 to shape and collimate the light beam emitted and received by the single-mode optical fiber 5. The length of the gradient refractive index optical fiber 4 is calculated according to the following formula:

[0088]

[0089] in, D SMF is the core diameter of single-mode optical fiber, DGIF is the core diameter of the graded-refractive-index optical fiber 4 , λ is the central wavelength of the light source, and NA is the numerical aperture of the graded-refractive-index optical fiber 4 .

[0090] The fiber Bragg grating on the single-mode fiber 5 is used for temperature sensing and temperature compensation of the FP cavity 101. The temperature pressure demodulation measurement matrix is:

[0091]

[0092] In the formula, k t is the temperature of the FP cavity 101; k p is the pressure measurement sensitivity of the FP cavity 101, k f is the temperature sensitivity of the fiber Bragg grating, Δλ is the wavelength drift, and ΔL is the change of the FP cavity 101.

[0093] The method for preparing the optical fiber cranial temperature and pressure composite monitoring probe of the present invention comprises the following steps:

[0094] S1. Using a femtosecond laser to write on the end face of a coreless optical fiber according to the designed corrugation shape parameters;

[0095] S2, using arc welding technology to weld the coreless optical fiber to the hollow glass tube 2, and cutting the hollow glass tube 2 to a suitable length;

[0096] S3, using arc welding technology to weld the single-mode optical fiber 5 engraved with the fiber grating and the graded refractive index optical fiber 4;

[0097] S4, using a fiber cleaver under a microscope to cut the graded refractive index optical fiber 4 to a suitable length;

[0098] S5, after polishing the end face of the single-mode optical fiber 5, insert it into the hollow glass tube 2 using the optical fiber fusion splicing platform, then adjust the feeding amount of the fusion splicing platform to control the insertion process of the single-mode optical fiber 5, and monitor the cavity length of the formed FP cavity 101 by the FP cavity white light interference demodulation algorithm, and when the preset cavity length is reached and the interference spectrum contrast is good, control the fusion splicing platform to discharge and fuse the single-mode optical fiber 5 and the hollow glass tube 2;

[0099] S6. Using a fiber cleaver under a microscope, cut the coreless optical fiber to a length of 1 mm, and further reduce its length to less than 0.1 mm using a bare optical fiber grinder;

[0100] S7. Use a femtosecond laser to further thin the length of the coreless optical fiber, and write grooves according to a preset waveform shape to form a pressure diaphragm 1. Finally, use a chemical plating or measurement and control sputtering process to coat a metal coating 3 on the surface of the diaphragm to complete the preparation of the corrugated diaphragm FP cavity interventional optical fiber intracranial temperature and intracranial pressure composite monitoring probe.

[0101] Specifically, all welding steps are performed under a vacuum environment.

[0102] Among them, the pressure diaphragm 1 is made of coreless optical fiber through femtosecond laser technology, and its corrugation shape is rectangular or sinusoidal. The pressure diaphragm 1 is used to reduce the processing stress in the diaphragm under the traditional grinding process, improve the pressure sensing sensitivity, and reduce the zero drift of the sensor caused by temperature and moisture.

[0103] Among them, the preparation method can improve the pressure sensitivity and can be precisely controlled by adjusting the depth, width and number of cycles of corrugation processing.

[0104] The optical fiber cranial temperature and pressure composite monitoring probe of the present invention is applied to medical devices, such as a cranial cavity monitoring probe.

[0105] like Figure 5 As shown, the cranial cavity monitoring probe is used to detect cranial temperature and pressure, the reed switch 6 is a hollow structure; the metal capillary 9 is arranged in the reed switch 6 and is fixed by the glue 8; the optical fiber cranial temperature and pressure composite monitoring probe is integrated in the metal capillary 7; the probe front end 9 is arranged at the end of the reed switch 6, and the end of the probe front end 9 is set as a hemispherical shell structure;

[0106] As shown in the above structure, in the figure, the mark 10 is the optical fiber cranial temperature and cranial pressure composite monitoring probe of the present invention, wherein the reed tube 6 has the advantage of being freely bendable, so as to facilitate driving the optical fiber cranial temperature and cranial pressure composite monitoring probe 10 into the cranial cavity;

[0107] The end of the front end 9 of the probe is set as a hemispherical shell structure, which can effectively prevent scratching tissue when entering the human body;

[0108] Furthermore, a strip-shaped slot is provided on the front end 9 of the probe to ensure that the pressure can be transmitted normally.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical fiber cranial temperature and pressure composite monitoring probe, characterized in that: It comprises a pressure diaphragm (1), a hollow glass tube (2), a metal coating (3), a gradient refractive index optical fiber (4) and a single-mode optical fiber (5), wherein: The pressure diaphragm (1) is in a corrugated shape, and the corrugated shape is rectangular or sinusoidal; One end of the hollow glass tube (2) is connected to the pressure diaphragm (1); The metal coating (3) is arranged on a surface of the pressure diaphragm (1) away from the hollow glass tube (2); The graded-refractive-index optical fiber (4) is arranged in the hollow glass tube (2), and the graded-refractive-index optical fiber (4) is spaced apart from a pressure diaphragm (1) to form an FP cavity (101), and the pressure diaphragm (1) has a protruding plane portion (11) corresponding to the collimated light beam; One end of the single-mode optical fiber (5) is inserted into the hollow glass tube (2) and connected to the graded-refractive-index optical fiber (4); a fiber grating is engraved on the single-mode optical fiber (5).

2. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 1, characterized in that: The diameter ratio of the single-mode optical fiber (5) to the graded-refractive-index optical fiber (4) is 1:

1.

3. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 2, characterized in that: It also includes a reed switch (6), a metal capillary (7), glue (8) and a probe front end (9), wherein: The reed pipe (6) is a hollow structure; The metal capillary (7) is arranged in the reed tube (6) and is bonded and fixed by the glue (8); The pressure diaphragm (1), the hollow glass tube (2), the metal coating (3), the graded-refractive-index optical fiber (4) and the single-mode optical fiber (5) are integrated in the metal capillary (7); The front end (9) of the probe is arranged at the end of the reed tube (6), and the end of the front end (9) of the probe is arranged as a hemispherical shell structure.

4. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 3, characterized in that: The relationship between the deformation displacement of the corrugated pressure diaphragm and the load P is: in, Wherein, E is the elastic modulus of the pressure diaphragm (1); v is the Poisson's ratio of the pressure diaphragm (1); h is the thickness of the pressure diaphragm (1); d is the radius of the pressure diaphragm (1); q is the profile coefficient of the pressure diaphragm (1), which is used to measure the profile of the pressure diaphragm (1); represents the ratio of the actual distance from the center to the edge of the pressure diaphragm (1) measured along the corrugation profile to its radius; H is the corrugation depth; L is the corrugation width; S is the corrugation arc length; N is the number of corrugation cycles; ΔX is the deformation displacement of the corrugated diaphragm; K p is the temperature in the FP chamber (101); J p is the formula coefficient.

5. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 4, characterized in that: When the pressure diaphragm (1) is deformed by a relatively large initial stress, considering its initial stress σ0, the relationship between its load P and the deformation displacement of the diaphragm is: The corrugated diaphragm (1) is designed with the consideration that The load P and the displacement ΔX are approximately in a linear relationship. It can be seen from the above formula that when subjected to a large initial stress, the lateral deformation of the corrugated diaphragm (1) reduces its axial displacement by Times, perform linear superposition on the above formula, and only consider the linear part to simplify the calculation, as shown below: From the above formula, it can be obtained that the expression of the deformation displacement ΔX of the pressure diaphragm (1) is:

6. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 5, characterized in that: The material of the metal plating layer (3) is one of gold, silver, nickel and copper. The theoretical expression of the interference spectrum of the FP cavity (101) is: Wherein, R1 is the reflectivity of the end face of the graded-refractive-index optical fiber (4), R2 is the reflectivity of the inner surface of the pressure diaphragm (1), R3 is the reflectivity of the surface of the metal coating (3), and η1, η2, and η3 are the intensity loss coefficients of the light beam at the end face of the graded-refractive-index optical fiber (4), the inner surface of the pressure diaphragm (1), and the surface of the metal coating (3); is the phase difference generated when the light beam passes through the FP cavity (101) for interference, It is the phase difference generated when the light beam passes through the inner and outer surfaces of the pressure diaphragm (1).

7. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 6, characterized in that: The graded-refractive-index optical fiber (4) is fused with the single-mode optical fiber (5) to shape and collimate the light beam emitted and received by the single-mode optical fiber (5). The length of the graded-refractive-index optical fiber (4) is calculated according to the following formula: in, D SMF is the core diameter of the single-mode optical fiber (5), D GIF is the core diameter of the graded-refractive-index optical fiber (4), λ is the central wavelength of the light source, and NA is the numerical aperture of the graded-refractive-index optical fiber (4).

8. The optical fiber cranial temperature and pressure composite monitoring probe according to claim 7, characterized in that: The fiber Bragg grating on the single-mode optical fiber (5) is used for temperature sensing and temperature compensation of the FP cavity (101), and the temperature pressure demodulation measurement matrix is: In the formula, k t is the temperature of the FP cavity (101); k p is the pressure measurement sensitivity of the FP chamber (101), k f is the temperature sensitivity of the fiber Bragg grating, Δλ is the wavelength drift, and ΔL is the change of the FP cavity (101).

9. A method for preparing a probe, for preparing the optical fiber cranial temperature and pressure composite monitoring probe according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Using a femtosecond laser to write on the end face of a coreless optical fiber according to the designed corrugation shape parameters; S2, using arc welding technology to weld the coreless optical fiber to the hollow glass tube (2), and cutting the hollow glass tube (2) to a suitable length; S3, using arc welding technology to weld the single-mode optical fiber (5) engraved with the fiber grating and the graded refractive index optical fiber (4); S4, using a fiber cleaver under a microscope to cut the graded refractive index optical fiber (4) to a suitable length; S5, after grinding and polishing the end face of the single-mode optical fiber (5), insert it into the hollow glass tube (2) using an optical fiber fusion splicing platform, then adjust the feeding amount of the fusion splicing platform to control the insertion process of the single-mode optical fiber (5), and monitor the formed cavity length of the FP cavity (101) by using the FP cavity white light interference demodulation algorithm. When the preset cavity length is reached and the interference spectrum contrast is good, control the fusion splicing platform to discharge and fuse the single-mode optical fiber (5) and the hollow glass tube (2); S6. Using a fiber cleaver under a microscope, cut the coreless optical fiber to a length of 1 mm, and further reduce its length to less than 0.1 mm using a bare optical fiber grinder; S7. A femtosecond laser is used to further reduce the length of the coreless optical fiber, and a groove can be engraved according to a preset waveform shape to form the pressure diaphragm (1). Finally, the metal coating (3) is coated on the surface of the diaphragm using a chemical plating or a measurement and control sputtering process to complete the preparation of a corrugated diaphragm FP cavity intervention optical fiber intracranial temperature and intracranial pressure composite monitoring probe.

10. The method for preparing a probe according to claim 9, characterized in that: All welding steps are performed under vacuum.

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