Micro-channel pressure vibration composite optical fiber F-P sensor and preparation method thereof

Abstract

The invention relates to a micro-channel type pressure vibration composite optical fiber F-P sensor and a preparation method thereof.The sensor comprises a first structural layer, a second structural layer and a third structural layer, the third structural layer comprises a silicon wafer, the silicon wafer is provided with a micro-channel set, a water inlet hole and an optical fiber channel hole, the water inlet hole penetrates through the silicon wafer and is communicated with the micro-channel set, and the optical fiber channel hole is communicated with the second structural layer; the second structural layer comprises a glass sheet, a plurality of cavity holes and an optical fiber channel groove are formed in the peripheral edge of the glass sheet, the optical fiber channel groove is communicated with a part of the cavity holes, and one side of the glass sheet is attached to one side of the silicon wafer so that one end of each cavity hole can be communicated with the periphery of the micro-channel group; one side of the silicon layer diaphragm is attached to the glass sheet, the other side of the silicon layer diaphragm is attached to the other side of the glass sheet to close the other end of the cavity hole, so that the cavity hole forms an F-P cavity, and a mass block is attached to the interior of a part of the F-P cavity, the micro-channel group is communicated with the cavity, when water enters the micro-channel group through the water inlet hole, air in the cavity at one end of the micro-channel group is compressed, the pressure intensity is increased, and the mass block is attached to the interior of the F-P cavity. And the internal and external pressure difference of the cavity is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-electromechanical systems, and in particular relates to a micro-channel pressure-vibration composite optical fiber FP sensor and a preparation method thereof. Background Art

[0002] Fiber optic FP sensor is a high-precision sensor based on the Fabry-Perot interferometer principle. It has the advantages of high sensitivity, anti-electromagnetic interference and small size. It is widely used in aerospace, oil and gas, civil engineering, power systems, medical treatment, environmental monitoring, industrial manufacturing and scientific research, and has promoted technological progress in many related industries.

[0003] As a type of fiber FP sensor, the pressure-vibration composite fiber FP sensor integrates the two functions of pressure measurement and vibration measurement. When external pressure acts on the sensor, the length of the FP cavity of the sensor changes, causing the interference fringes to move. By detecting the distance the fringes move, the pressure can be calculated; similarly, when external vibration acts on the sensor, the vibration sensitive element will undergo periodic displacement, causing the length of the FP cavity to change dynamically, which in turn causes the change of the interference fringes. By detecting and analyzing this change, the frequency and amplitude of the vibration and other information can be calculated.

[0004] Vibration signals are vector signals that contain amplitude, frequency, phase, and direction information. In underwater environments, vibrations usually appear as fluctuations in three-dimensional space, so it is necessary to measure the vibration components in the horizontal direction of the X-axis, the horizontal direction of the Y-axis, and the vertical direction of the Z-axis to fully describe the vibration state. It is of great significance to measure the vibration components in the X-axis, Y-axis, and Z-axis directions underwater, which can not only fully describe the vibration state, but also identify the source of vibration, improve positioning accuracy, and analyze vibration propagation characteristics to support environmental monitoring and disaster warning. Therefore, by measuring the vibration components in three directions, we can have a deeper understanding of underwater vibration phenomena and provide important support for scientific research and technological applications in related fields.

[0005] When the diaphragm type pressure-vibration composite optical fiber FP sensor works in water, there is generally a hydrostatic pressure loaded in front of the sensitive diaphragm. Due to the internal and external pressure difference, the sensitive diaphragm is easily bent or ruptured, resulting in a decrease in the sensitivity of the sensor and a change in the dynamic range. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a microfluidic channel pressure-vibration composite optical fiber FP sensor and a preparation method thereof, which solves the problem of internal and external pressure balance of the diaphragm optical fiber FP sensor under different water depths by constructing a microfluidic group connected to the FP cavity to enhance the pressure inside the FP cavity, thereby greatly improving the pressure resistance and sensitivity of the sensor.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The present invention first provides a microfluidic pressure-vibration composite optical fiber FP sensor, comprising a first structural layer, a second structural layer and a third structural layer which are stacked and bonded together. The third structural layer comprises a silicon wafer, on which a microfluidic channel group, a water inlet hole and an optical fiber channel hole are arranged. The microfluidic channel group is located on one side of the silicon wafer, and the microfluidic channel group extends from the middle of the silicon wafer to the periphery. The water inlet hole passes through the silicon wafer and is connected with the microfluidic channel group. The second structural layer comprises a glass wafer, on the peripheral edge of the glass wafer a plurality of cavities are arranged, and on the periphery of the glass wafer an optical fiber channel groove is also arranged which passes through a portion of the corresponding cavities. One side of the glass wafer is bonded to one side of the silicon wafer so that one end of the cavity is connected with the periphery of the microfluidic channel group, and one end of the optical fiber channel hole passes through another portion of the corresponding cavities. The first structural layer comprises a silicon layer diaphragm, and one side of the silicon layer diaphragm is bonded to the other side of the glass wafer to seal the other end of each cavity so that the cavity forms an FP cavity.

[0008] Furthermore, the microchannel group is composed of a plurality of spiral channel rings, one end of the channel intersects at the water inlet hole, and the other end of the channel extends toward the outer edge of the silicon wafer and is connected to the corresponding cavity hole.

[0009] Furthermore, the plurality of cavity holes are respectively a scalar cavity, a Z-axis component cavity, an X-axis component cavity and a Y-axis component cavity; a pair of the optical fiber channel holes vertically penetrate the scalar cavity and the Z-axis component cavity respectively, and a pair of the optical fiber channel grooves horizontally penetrate the X-axis component cavity and the Y-axis component cavity.

[0010] Furthermore, a Z-axis mass block extending into the Z-axis component cavity is provided on one side of the silicon layer diaphragm, an X-axis mass block is provided on the inner wall of the X-axis component cavity, and a Y-axis mass block is provided on the inner wall of the Y-axis component cavity, and one side of the silicon layer diaphragm on which the Z-axis mass block is provided is bonded to the glass sheet.

[0011] Furthermore, the cavities are respectively communicated with the other ends of the corresponding flow channels.

[0012] The present invention also provides a method for preparing a micro-channel pressure-vibration composite optical fiber FP sensor, comprising the following steps: Step 1, first etching a microchannel group on one side surface of the silicon wafer, and then etching a water inlet hole and an optical fiber channel hole to form a third structural layer; Step 2, sequentially drilling cavities and optical fiber channel grooves on the glass sheet to form a second structural layer, and reserving an X-axis mass block and a Y-axis mass block in the drilled cavities respectively; Step 3, etching a Z-axis mass block on the silicon layer membrane to form a first structural layer; Step 4: sequentially bond the first structure layer, the second structure layer and the third structure layer, remove the substrate layer and the buried oxide layer of the first structure layer, and finally slice to obtain the sensor chip.

[0013] Furthermore, in step 1, the etching of the microchannel group, the water inlet hole and the pair of optical fiber channel holes all include the following steps: Step 101, spin-coating a photoresist on one surface of a silicon wafer as a mask; Step 102, using a mask plate to expose and develop the surface of the silicon wafer on which the photoresist is spin-coated to form an etching window; Step 103, etching the etching window; Step 104, cleaning off the photoresist.

[0014] Further, the step 2 specifically includes: Step 201, four cavities are drilled on the glass sheet, and an X-axis mass block and a Y-axis mass block are reserved in two of the cavities respectively; Step 202, a pair of optical fiber channel grooves are cut on one side surface of the glass sheet, one optical fiber channel groove is connected to the cavity hole of the reserved X-axis mass block, and the other optical fiber channel groove is connected to the cavity hole of the reserved Y-axis mass block.

[0015] Further, the step 3 specifically includes: Step 301, coating a photoresist on one side of the silicon layer membrane as a mask; Step 302, using a mask to expose the silicon layer membrane coated with photoresist, after etching a portion of the silicon layer membrane around the mask, a Z-axis mass block is obtained on one side of the silicon layer membrane; Step 303, after removing the photoresist on the surface of the Z-axis mass block, a first structural layer with a substrate layer and a buried oxide layer is obtained.

[0016] Further, the step 4 specifically includes: Step 401, cleaning the first structural layer, the second structural layer and the third structural layer; Step 402, electrostatically bonding the first structure layer, the second structure layer, and the third structure layer to form a bonded wafer; Step 403, plugging the optical fiber channel hole, optical fiber channel groove and water inlet hole, and removing the substrate layer and the buried oxide layer of the first structural layer; Step 404 , after the outer peripheral surface of the bonded wafer reaches a hydrophobic state, dicing is performed to obtain sensor chips.

[0017] The present invention adopts the above technical solution, which has the following advantages and effects: The present invention provides a microchannel pressure-vibration composite optical fiber FP sensor and a preparation method thereof, wherein the sensor realizes internal and external pressure balance by arranging a spiral annular channel to form a microchannel group connected to an FP cavity. When water enters the microchannel group, the air in the microchannel group is compressed into each FP cavity, so that the FP cavity is connected to the external environment while the FP cavity is always filled with air. Since the air in the FP cavity is compressed, the pressure in the FP cavity increases, achieving internal and external pressure balance, reducing the influence of the internal and external pressure difference on the sensor performance, and improving the pressure resistance of the sensor. At the same time, since the FP cavity is always filled with air instead of water, the sensitivity is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a perspective structural schematic diagram of the micro-channel pressure-vibration composite optical fiber FP sensor of the present invention.

[0019] Figure 2 It is a schematic diagram of the first structural layer of the present invention.

[0020] Figure 3 It is a schematic diagram of the second structural layer of the present invention.

[0021] Figure 4 It is a schematic diagram of the third structural layer of the present invention.

[0022] The reference numerals are as follows: 1- microfluidic channel group, 2- water inlet hole, 3- first optical fiber channel hole, 4- second optical fiber channel hole, 5- Z-axis component cavity, 6- X-axis component cavity, 7- Y-axis component cavity, 8- scalar cavity, 9- first optical fiber channel groove, 10- X-axis mass block, 11- Y-axis mass block, 12- Z-axis mass block, 13- second optical fiber channel groove. DETAILED DESCRIPTION

[0023] The embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0024] like Figure 1-Figure 4As shown. A microfluidic pressure-vibration composite optical fiber FP sensor of the present invention comprises a first structural layer, a second structural layer and a third structural layer which are stacked and bonded in sequence. The third structural layer comprises a silicon wafer, on which a microfluidic group 1, a water inlet 2 and an optical fiber channel hole are arranged. The microfluidic group 1 is located on one side of the silicon wafer, and the microfluidic group 1 extends from the middle of the silicon wafer to the periphery. The water inlet 2 passes through the silicon wafer and is connected with the microfluidic group 1. The second structural layer comprises a glass sheet, on the outer peripheral edge of the glass sheet there are a plurality of cavities, and on the outer periphery of the glass sheet there are also optical fiber channel grooves which pass through a portion of the corresponding cavities, one side of the glass sheet is bonded to one side of the silicon sheet so that one end of the cavity is connected to the periphery of the microfluidic group 1, and one end of the optical fiber channel hole is connected to another portion of the corresponding cavities. The first structural layer comprises a silicon layer diaphragm, one side of the silicon layer diaphragm is bonded to the other side of the glass sheet to close the other end of the cavity, so that the cavity forms an FP cavity, and a mass block is bonded to a portion of the FP cavity.

[0025] Specifically, the first structure layer, the second structure layer and the third structure layer are bonded and connected in sequence. Each cavity hole on the glass sheet is sealed by a silicon sheet and a silicon layer membrane to form an FP cavity for detecting scalar and vector quantities. The fiber channel hole and the fiber channel groove are respectively used to insert optical fibers and conduct the corresponding FP cavity to transmit optical signals.

[0026] Before the sensor is put into water, there is air inside the microfluidic group 1 and the pressure is normal atmospheric pressure. After being put into water, one side of the microfluidic group 1 is at atmospheric pressure and the other side is at water pressure. Since the water pressure is greater than the atmospheric pressure, there is a pressure difference, which pushes the water flow into the microfluidic group 1. At this time, the air on one side of the microfluidic group 1 is compressed, and when the pressure increases to the same as the water pressure, the water will no longer flow. At the same time, part of the air in the microfluidic group 1 is pushed into the FP cavity, which causes the pressure in the FP cavity to increase, reducing the impact of the internal and external pressure difference on the sensor performance.

[0027] Furthermore, the microchannel group 1 is composed of a plurality of spiral rings of channels, one end of which intersects at the water inlet 2, and the other end of which extends toward the outer edge of the silicon wafer and communicates with the corresponding FP cavity.

[0028] Specifically, in the present invention, the microfluidic channel group 1 is composed of four "⺋"-shaped spiral flow channel rings, the number of flow channels is consistent with the number of cavities, the inner ends of the four spiral flow channels intersect at the water inlet hole 2 in the center of the silicon wafer, the four spiral flow channels spirally unfold from the water inlet hole 2, and the outer ends of the four spiral flow channels are distributed and extend to the outer peripheral edge of the silicon wafer. When the silicon wafer and the glass wafer are bonded, the outer ends of the four spiral flow channels are respectively connected to the cavities distributed in the array on the glass wafer.

[0029] As a preferred embodiment, the microchannel group 1 is composed of a plurality of spiral channel rings. The length of each channel of the microchannel group 1 is sufficient to prevent water from flowing into the interlinked FP cavities under the action of pressure difference after entering the channel.

[0030] Furthermore, in order to achieve simultaneous measurement of scalar, X-axis component, Y-axis component and Z-axis component, the several cavity holes are respectively the scalar cavity 8, the Z-axis component cavity 5, the X-axis component cavity 6 and the Y-axis component cavity 7, a pair of optical fiber channel holes vertically penetrate the scalar cavity 8 and the Z-axis component cavity 5 respectively, and a pair of optical fiber channel grooves horizontally penetrate the X-axis component cavity 6 and the Y-axis component cavity 7 respectively.

[0031] Specifically, the X-axis component cavity 6 and the Y-axis component cavity 7 are respectively arranged at intervals on the two side edges perpendicular to each other at one end of the glass sheet, and the edges of the X-axis component cavity 6 and the Y-axis component cavity 7 close to the glass sheet are glass films. The scalar cavity 8 and the Z-axis component cavity 5 are respectively arranged in the other end of the glass sheet. A pair of fiber channel holes are respectively the first fiber channel hole 3 and the second fiber channel hole 4, the first fiber channel hole 3 vertically penetrates the scalar cavity 8, and the second fiber channel hole 4 vertically penetrates the Z-axis component cavity 5. A pair of fiber channel grooves are respectively the first fiber channel groove 9 and the second fiber channel groove 13, and the first fiber channel groove 9 and the second fiber channel groove 13 are both L-shaped structures. One end of the first fiber channel groove 9 penetrates one side edge of the glass sheet, and the other end penetrates the X-axis component cavity 6, and one end of the second fiber channel groove 13 penetrates one side edge of the glass sheet, and the other end penetrates the Y-axis component cavity 7. During measurement, optical fibers are inserted into the first fiber channel hole 3, the second fiber channel hole 4, the first fiber channel groove 9, and the second fiber channel groove 13.

[0032] The present invention sets four FP cavities. After the microchannel group 1 is connected to the four FP cavities, three FP cavities are used to measure the vibration signal components in the X-axis, Y-axis and Z-axis directions respectively, and one FP cavity is used to measure the pressure scalar, thereby achieving the purpose of pressure-vibration compounding.

[0033] Furthermore, in order to enhance the sensitivity of the sensor, adjust the frequency response characteristics, stability and anti-interference ability, a mass block is configured in each component cavity. In order to improve the directionality of the Z-axis component cavity 5 in sensing the Z-axis vibration component information, a Z-axis mass block 12 extending into the Z-axis component cavity 5 is arranged on one side of the silicon layer diaphragm, and in order to improve the directionality of the X-axis component cavity 6 and the Y-axis component cavity 7 in sensing the X-axis vibration component and the Y-axis vibration component information, an X-axis mass block 10 is arranged on the inner wall of the X-axis component cavity 6, and a Y-axis mass block 11 is arranged on the inner wall of the Y-axis component cavity 7. One side of the silicon layer diaphragm where the Z-axis mass block 12 is arranged is attached to the glass sheet to close one end of the cavity hole.

[0034] Specifically, one side of the Z-axis mass block 12 is attached to one side of the silicon layer diaphragm and is integrated with it. After the silicon layer diaphragm and the glass sheet are bonded together, the Z-axis mass block 12 is embedded in one end of the Z-axis component cavity 5 and is spaced opposite to the second optical fiber channel hole 4. The X-axis mass block 10 is arranged on the glass film side of the X-axis component cavity 6 and is spaced opposite to one end of the first optical fiber channel groove 9. The Y-axis mass block 11 is arranged on the glass film side of the Y-axis component cavity 7 and is spaced opposite to one end of the second optical fiber channel groove 13.

[0035] The silicon layer diaphragm on one side of the scalar cavity 8 is used to sense the corresponding pressure scalar, the silicon layer diaphragm on one side of the Z-axis component cavity 5 is used to sense the Z-axis vibration component, and the glass film on one side of the X-axis component cavity 6 and the Y-axis component cavity 7 is used to sense the X-axis vibration component and the Y-axis vibration component, respectively, so that the vibration signal components can be measured simultaneously from the three directions of X-axis, Y-axis and Z-axis.

[0036] Further, the scalar cavity 8, the Z-axis component cavity 5, the X-axis component cavity 6 and the Y-axis component cavity 7 are respectively connected to the other end of the corresponding flow channel, and the water flows into different flow channels through the water inlet hole 2 to balance the pressure inside and outside the scalar cavity 8, the Z-axis component cavity 5, the X-axis component cavity 6 and the Y-axis component cavity 7. The length of the flow channel is designed according to the pressure to ensure that the pressure balance is achieved after the water flows into the flow channel and does not enter each cavity.

[0037] A method for preparing a micro-channel pressure-vibration composite optical fiber FP sensor of the present invention comprises the following steps: Step 1, preparation of the third structural layer: that is, firstly etching a micro-channel group 1 on one side surface of the silicon wafer, and then etching a water inlet hole 2 and a pair of optical fiber channel holes to form the third structural layer.

[0038] Specifically, the processing procedures of the microfluidic channel group 1, the water inlet hole 2 and the optical fiber channel hole are the same.

[0039] First, a double-polished single-crystal silicon wafer is selected for cleaning, and the cleaned silicon wafer is first processed into micro-channel group 1, and then the water inlet hole 2 and the optical fiber channel hole are processed. The processing process of micro-channel group 1 is taken as an example for description.

[0040] The processing process of microfluidic group 1 is as follows: Step 101, select photoresist as a mask, and spin-coat the photoresist on the surface of the silicon wafer as a mask through a coating machine. After the photoresist is spin-coated, the silicon wafer after the photoresist is spin-coated is soft-baked in a spin-coating hot plate system to remove the solution in the photoresist and dry the photoresist.

[0041] Step 102: Use the prepared microfluidic group mask to expose the uncovered surface of the silicon wafer, then place the photolithography silicon wafer in a developer for development, and place the developed silicon wafer in a spin coating hot plate system for heating to remove residual water and developer, thereby forming a microfluidic group etching window.

[0042] Step 103 , performing ICP etching on the microchannel group etching window to form a microchannel group 1 .

[0043] Step 104: After the etching of the microchannel group 1 is completed, the residual photoresist on the surface of the silicon wafer is cleaned and removed.

[0044] When processing the optical fiber channel hole and the water inlet hole 2 on the silicon wafer, the processing steps of the optical fiber channel hole and the water inlet hole 2 are the same as the processing steps of the microfluidic channel group 1. The difference is that the processing of the optical fiber channel hole uses an optical fiber channel hole mask plate, and the processing of the water inlet hole 2 uses a water inlet hole mask plate.

[0045] Step 2, preparation of the second structural layer: that is, four cavities and a pair of optical fiber channel grooves are sequentially drilled on the glass sheet, the four cavities are sequentially scalar cavity 8, Z-axis component cavity 5, X-axis component cavity 6 and Y-axis component cavity 7. In the process of drilling the cavities, an X-axis mass block 10 is reserved in the X-axis component cavity 6, and a Y-axis mass block 11 is reserved in the Y-axis component cavity 7 to form the second structural layer. At the same time, one end of the drilled first optical fiber channel groove 9 horizontally penetrates the X-axis component cavity 6, and one end of the drilled second optical fiber channel groove 13 horizontally penetrates the Y-axis component cavity 7.

[0046] Specifically, the following steps are included: Step 201, take a BF33 glass sheet, and use a glass punch to drill four holes on the glass sheet, which are scalar cavity 8, Z-axis component cavity 5, X-axis component cavity 6 and Y-axis component cavity 7. Scalar cavity 8 and Z-axis component cavity 5 are arranged at one end of the glass sheet, X-axis component cavity 6 and Y-axis component cavity 7 are located at the edge of the other end of the glass sheet, and an X-axis mass block 10 is reserved on one side of the glass film in the X-axis component cavity 6, and a Y-axis mass block 11 is reserved on one side of the glass film in the Y-axis component cavity 7.

[0047] Step 202, a pair of optical fiber channel grooves are cut on one side surface of the glass sheet. When cutting, one end of the first optical fiber channel groove 9 passes through the outer peripheral surface of the glass sheet, and the other end horizontally passes through the X-axis component cavity 6 and is spaced and opposite to the X-axis mass block 10, and one end of the second optical fiber channel groove 13 passes through the outer peripheral surface of the glass sheet, and the other end horizontally passes through the Y-axis component cavity 7 and is spaced and opposite to the Y-axis mass block 11.

[0048] Step 3: Etch the Z-axis mass block 12 on the silicon layer membrane to form a first structural layer.

[0049] Specifically, the following steps are included: Step 301, selecting a device layer of an SOI wafer as a silicon layer membrane, wherein the SOI wafer comprises a device layer, a buried oxide layer and a substrate layer from top to bottom; Step 302, first clean the SOI wafer, and then coat a photoresist on the device layer side of the SOI wafer as a mask for the Z-axis mass block region; Then, use the prepared mask template to block the uncovered peripheral area of ​​the Z-axis mass block and then expose it to obtain an etching window in the peripheral area of ​​the Z-axis mass block, and etch the SOI wafer device layer of the etching window in the peripheral area of ​​the Z-axis mass block. After etching, the Z-axis mass block 12 is obtained on the surface of the device layer of the SOI wafer.

[0050] Step 303 , after cleaning and removing the photoresist on the surface of the Z-axis mass block 12 , a first structural layer with a buried oxide layer and a substrate layer is obtained.

[0051] Step 4: Bond the first structure layer, the second structure layer and the third structure layer in sequence, remove the substrate layer and the buried oxide layer of the first structure layer, and finally slice to obtain the sensor chip.

[0052] Specifically, the following steps are included: Step 401: Use a cleaning solution to clean the first structure layer, the second structure layer and the third structure layer respectively to remove surface residues of the first structure layer, the second structure layer and the third structure layer so that they all meet the bonding standard.

[0053] Step 402: Use a bonding machine to electrostatically bond the first structure layer, the second structure layer, and the third structure layer to form a bonded wafer.

[0054] Step 403, the substrate layer on the first structural layer of the bonded wafer is etched away by ICP etching to expose the buried oxide layer, and the ends of the optical fiber channel holes, water inlet holes and optical fiber channel grooves on the bonded wafer are sealed with a UV film, and then the bonded wafer is immersed in hydrofluoric acid to remove the buried oxide layer of the first structural layer, and then the residual hydrofluoric acid is cleaned and the moisture is blown away with nitrogen to make the surface of the bonded wafer hydrophobic.

[0055] Step 404: remove the UV film on the surface of the bonded wafer to obtain a whole-board chip; and slice the whole-board chip using a dicing machine to obtain a sensor chip.

[0056] During packaging, the present invention inserts four optical fibers into corresponding four FP cavities through a pair of optical fiber channel holes and a pair of optical fiber channel grooves. When a signal is transmitted, the signal will cause the silicon layer diaphragm and the glass film of the sensor to vibrate, resulting in a change in the cavity length of the FP cavity of the sensor, causing changes in interference signals between the reflected light of the optical fiber end face and the reflected light of the silicon layer diaphragm and the reflected light of the glass film. By demodulating the four interference signals respectively, information on pressure and vibration components in three directions can be obtained.

[0057] 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 make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A micro-channel pressure-vibration composite optical fiber FP sensor, characterized in that: The invention comprises a first structural layer, a second structural layer and a third structural layer which are laminated and bonded together. The third structural layer comprises a silicon wafer, on which a microfluidic channel group (1), a water inlet hole (2) and a fiber channel hole are arranged. The microfluidic channel group (1) is located on one side of the silicon wafer, and the microfluidic channel group (1) extends from the middle of the silicon wafer to the periphery. The water inlet hole (2) passes through the silicon wafer and is connected to the microfluidic channel group (1). The second structural layer comprises a glass wafer, on the periphery of which a plurality of cavities are arranged. The periphery of the glass wafer is also provided with a fiber channel groove which passes through a portion of the corresponding cavities. One side of the glass wafer is bonded to one side of the silicon wafer so that one end of the cavity is connected to the periphery of the microfluidic channel group (1), and one end of the fiber channel hole passes through another portion of the corresponding cavities. The first structural layer comprises a silicon layer membrane, and one side of the silicon layer membrane is bonded to the other side of the glass wafer so that the other end of each cavity is sealed so that the cavity forms an FP cavity.

2. The micro-channel pressure-vibration composite optical fiber FP sensor according to claim 1, characterized in that: The microchannel group (1) is composed of a plurality of spiral channel rings, one end of the channel intersects at the water inlet hole (2), and the other end of the channel extends toward the outer edge of the silicon wafer and is connected to the corresponding cavity hole.

3. The micro-channel pressure-vibration composite optical fiber FP sensor according to claim 2, characterized in that: The plurality of cavity holes are respectively a scalar cavity (8), a Z-axis component cavity (5), an X-axis component cavity (6) and a Y-axis component cavity (7); a pair of optical fiber channel holes respectively vertically penetrate the scalar cavity (8) and the Z-axis component cavity (5), and a pair of optical fiber channel grooves respectively horizontally penetrate the X-axis component cavity (6) and the Y-axis component cavity (7).

4. The micro-channel pressure-vibration composite optical fiber FP sensor according to claim 3, characterized in that: A Z-axis mass block (12) extending into the Z-axis component cavity (5) is arranged on one side of the silicon layer diaphragm, an X-axis mass block (10) is arranged on the inner wall of the X-axis component cavity (6), and a Y-axis mass block (11) is arranged on the inner wall of the Y-axis component cavity (7), and the side of the silicon layer diaphragm on which the Z-axis mass block (12) is arranged is bonded to the glass sheet.

5. The micro-channel pressure-vibration composite optical fiber FP sensor according to claim 4, characterized in that: The cavities are respectively communicated with the other ends of the corresponding flow channels.

6. A method for preparing a micro-channel pressure-vibration composite optical fiber FP sensor according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1, first etching a microchannel group (1) on one side surface of the silicon wafer, and then etching a water inlet hole (2) and an optical fiber channel hole to form a third structural layer; Step 2, sequentially drilling cavities and optical fiber channel grooves on the glass sheet to form a second structural layer, and reserving an X-axis mass block (10) and a Y-axis mass block (11) in the drilled cavities respectively; Step 3, etching a Z-axis mass block (12) on the silicon layer membrane to form a first structural layer; Step 4: sequentially bond the first structure layer, the second structure layer and the third structure layer, remove the substrate layer and the buried oxide layer of the first structure layer, and finally slice to obtain the sensor chip.

7. The method for preparing the micro-channel pressure-vibration composite optical fiber FP sensor according to claim 6, characterized in that: In step 1, the etching of the microfluidic channel group (1), the water inlet hole (2) and the optical fiber channel hole all includes the following steps: Step 101, spin-coating a photoresist on one surface of a silicon wafer as a mask; Step 102, using a mask plate to expose and develop the surface of the silicon wafer on which the photoresist is spin-coated to form an etching window; Step 103, etching the etching window; Step 104, cleaning off the photoresist.

8. The method for preparing the micro-channel pressure-vibration composite optical fiber FP sensor according to claim 7, characterized in that: The step 2 specifically includes: Step 201, four cavities are drilled on the glass sheet, and an X-axis mass block (10) and a Y-axis mass block (11) are reserved in two of the cavities respectively; Step 202, a pair of optical fiber channel grooves are cut on one side surface of the glass sheet, one optical fiber channel groove is connected to the cavity hole of the reserved X-axis mass block (10), and the other optical fiber channel groove is connected to the cavity hole of the reserved Y-axis mass block (11).

9. The method for preparing the micro-channel pressure-vibration composite optical fiber FP sensor according to claim 8, characterized in that: The step 3 specifically includes: Step 301, coating a photoresist on one side of the silicon layer membrane as a mask; Step 302, using a mask to expose the silicon layer membrane coated with photoresist, after etching a portion of the silicon layer membrane around the mask, a Z-axis mass block (12) is obtained on one side of the silicon layer membrane; Step 303, after removing the photoresist on the surface of the Z-axis mass block (12), a first structural layer with a substrate layer and a buried oxide layer is obtained.

10. The method for preparing the micro-channel pressure-vibration composite optical fiber FP sensor according to claim 9, characterized in that: The step 4 specifically includes: Step 401, cleaning the first structure layer, the second structure layer and the third structure layer; Step 402, electrostatically bonding the first structure layer, the second structure layer and the third structure layer to form a bonded wafer; Step 403, plugging the optical fiber channel hole, the optical fiber channel groove and the water inlet hole (2), and removing the substrate layer and the buried oxide layer of the first structural layer; Step 404 , making the outer peripheral surface of the bonded wafer hydrophobic and then dicing to obtain sensor chips.

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