Microfluidic Vibration-Pressure Composite Fiber F-P Sensor and Its Preparation Method

Abstract

The present invention relates to a microchannel type pressure-vibration composite optical fiber F-P sensor and a preparation method thereof. The sensor includes a first structural layer, a second structural layer, and a third structural layer. The third structural layer includes a silicon wafer, on which a microchannel group, a water inlet hole, and an optical fiber channel hole are provided. The water inlet hole penetrates through the silicon wafer and is communicated with the microchannel group. The second structural layer includes a glass sheet, and a plurality of cavity holes and optical fiber channel grooves are provided on the outer peripheral edge of the glass sheet. The optical fiber channel groove is communicated with a part of the cavity holes. One side of the glass sheet is attached to one side of the silicon wafer so that one end of the cavity hole is communicated with the outer periphery of the microchannel group. The first structural layer includes a silicon layer diaphragm, and one side of the silicon layer diaphragm is attached to the other side of the glass sheet to seal the other end of the cavity hole so that the cavity hole forms an F-P cavity. A mass block is attached in a part of the F-P cavity. In the present invention, the microchannel group is communicated with the cavity. When water enters the microchannel group through the water inlet hole, the air in the cavity at one end of the microchannel group is compressed, and the pressure increases, reducing the pressure difference inside and outside the cavity.

Description

Technical Field

[0001] The present invention belongs to the technical field of microelectromechanical systems, and particularly relates to a microchannel type pressure and vibration composite optical fiber F-P sensor and a preparation method thereof. Background Art

[0002] The optical fiber F-P sensor is a high-precision sensor based on the Fabry-Perot interference principle, and has the advantages of high sensitivity, anti-electromagnetic interference and small volume. It has been widely used in the fields of aerospace, oil and gas, civil engineering, power systems, medical treatment, environmental monitoring, industrial manufacturing and scientific research, and has promoted the technological progress of many related industries.

[0003] As a kind of optical fiber F-P sensor, the pressure and vibration composite optical fiber F-P sensor integrates two functions of pressure measurement and vibration measurement. When an external pressure acts on the sensor, the length of the F-P cavity of the sensor changes, resulting in the movement of the interference fringes. By detecting the distance of the fringe movement, the magnitude of the pressure can be calculated. Similarly, when an external vibration acts on the sensor, the vibration-sensitive element will have a periodic displacement, causing the length of the F-P cavity to change dynamically, and then resulting in the change of the interference fringes. By detecting and analyzing this change, information such as the frequency and amplitude of the vibration can be calculated.

[0004] Vibration signals are vector signals, including amplitude, frequency, phase and direction information. In an underwater environment, vibration usually appears as fluctuations in three-dimensional space. Therefore, it is necessary to measure the vibration components in the horizontal directions of the X-axis, Y-axis and the vertical direction of the Z-axis respectively to completely describe the vibration state. Measuring the vibration components in the X-axis, Y-axis and Z-axis directions respectively underwater is of great significance. It can not only comprehensively describe the vibration state, but also identify the vibration source, improve the positioning accuracy, analyze the vibration propagation characteristics to support environmental monitoring and disaster warning. Therefore, by measuring the vibration components in three directions, the underwater vibration phenomenon can be understood more deeply, and important support can be provided for scientific research and technical applications in related fields.

[0005] When the diaphragm type pressure and vibration composite optical fiber F-P sensor works in water, there is generally a hydrostatic pressure applied in front of the sensitive diaphragm. Due to the internal and external pressure difference, it is easy for the sensitive diaphragm to deflect or rupture, resulting in the reduction of the sensitivity of the sensor and the change of the dynamic range. Summary of the Invention

[0006] Aiming at the above problems, the purpose of the present invention is to provide a microchannel type pressure and vibration composite optical fiber F-P sensor and a preparation method thereof. By constructing a microchannel group connected to the F-P cavity to enhance the pressure in the F-P cavity, the problem of internal and external pressure balance of the diaphragm type optical fiber F-P sensor under different water depths is solved, and the pressure resistance and sensitivity of the sensor are greatly improved.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The present invention first provides a microchannel type pressure-vibration composite fiber optic F-P sensor, which includes a first structural layer, a second structural layer and a third structural layer that are laminated and adhered. The third structural layer includes a silicon wafer, on which a microchannel group, a water inlet hole and an optical fiber channel hole are provided. The microchannel group is located on one side of the silicon wafer, and the microchannel group extends from the middle of the silicon wafer to the periphery. The water inlet hole penetrates the silicon wafer and communicates with the microchannel group; the second structural layer includes a glass sheet, and a plurality of cavity holes are provided at the outer peripheral edge of the glass sheet. An optical fiber channel groove is also provided on the outer periphery of the glass sheet and penetrates a part of the corresponding cavity holes. One side of the glass sheet is attached to one side of the silicon wafer so that one end of the cavity hole communicates with the outer periphery of the microchannel group, and one end of the optical fiber channel hole penetrates another part of the corresponding cavity holes; the first structural layer includes a silicon layer diaphragm, and one side of the silicon layer diaphragm is attached to the other side of the glass sheet to seal the other end of each cavity hole so that the cavity hole forms an F-P cavity.

[0009] Further, the microchannel group is composed of a plurality of channels spirally sleeved, one end of the channels converges at the water inlet hole, and the other end of the channels extends toward the outer edge of the silicon wafer and communicates with the corresponding cavity holes.

[0010] Further, 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 optical fiber channel holes respectively penetrate the scalar cavity and the Z-axis component cavity vertically, and a pair of optical fiber channel grooves penetrate the X-axis component cavity and the Y-axis component cavity horizontally.

[0011] Further, 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. The side of the silicon layer diaphragm provided with the Z-axis mass block is attached to the glass sheet.

[0012] Further, the cavity holes respectively communicate with the other ends of the corresponding channels.

[0013] The present invention also provides a preparation method for a microchannel type pressure-vibration composite fiber optic F-P sensor, including the following steps:

[0014] Step 1, first etch the microchannel group on one side surface of the silicon wafer, and then etch the water inlet hole and the optical fiber channel hole to form the third structural layer;

[0015] Step 2, sequentially drill cavity holes and optical fiber channel grooves on the glass sheet to form the second structural layer, and reserve an X-axis mass block and a Y-axis mass block respectively in the drilled cavity holes;

[0016] Step 3, etch the Z-axis mass block on the silicon layer diaphragm to form the first structural layer;

[0017] Step 4, bond the first structural layer, the second structural layer, and the third structural layer in sequence, then remove the substrate layer and the buried oxide layer of the first structural layer, and finally perform dicing to obtain the sensor chip.

[0018] Further, in the step 1, the etching of the microchannel group, the water inlet hole, and the pair of optical fiber channel holes all includes the following steps:

[0019] Step 101, spin-coat a photoresist on one side surface of the silicon wafer as a mask;

[0020] Step 102, use a mask plate to expose and develop the surface of the silicon wafer with the spin-coated photoresist to form an etching window;

[0021] Step 103, etch the etching window;

[0022] Step 104, wash off the photoresist.

[0023] Further, the step 2 specifically includes:

[0024] Step 201, drill 4 cavity holes in the glass sheet, and reserve an X-axis mass block and a Y-axis mass block in two of the cavity holes respectively;

[0025] Step 202, drill a pair of optical fiber channel grooves on one side surface of the glass sheet, one optical fiber channel groove communicates with the cavity hole reserved with the X-axis mass block, and the other optical fiber channel groove communicates with the cavity hole reserved with the Y-axis mass block.

[0026] Further, the step 3 specifically includes:

[0027] Step 301, coat a photoresist on one side surface of the silicon layer diaphragm as a mask;

[0028] Step 302, use a mask plate to expose the silicon layer diaphragm coated with the photoresist, and after etching a part of the silicon layer diaphragm outside the periphery of the mask plate, obtain a Z-axis mass block on one side of the silicon layer diaphragm;

[0029] Step 303, remove the photoresist on the surface of the Z-axis mass block to obtain the first structural layer with a substrate layer and a buried oxide layer.

[0030] Further, the step 4 specifically includes:

[0031] Step 401, clean the first structural layer, the second structural layer, and the third structural layer;

[0032] Step 402, perform electrostatic bonding on the first structural layer, the second structural layer, and the third structural layer to form a bonded wafer;

[0033] Step 403: Plug the optical fiber channel holes, optical fiber channel grooves and water inlet holes, and remove the substrate layer and buried oxide layer of the first structural layer;

[0034] Step 404: After making the outer peripheral surface of the bonding wafer hydrophobic, perform dicing to obtain the sensor chip.

[0035] Due to the adoption of the above technical solutions, the present invention has the following advantages and effects:

[0036] A microchannel type pressure-vibration composite optical fiber F-P sensor and a preparation method thereof provided by the present invention. The sensor realizes internal and external pressure balance by means of a spiral sleeve flow channel arranged to form a microchannel group communicating with the F-P cavity. When water enters the microchannel group, the air in the microchannel group is compressed into each F-P cavity, so that the F-P cavity is connected to the external environment and the F-P cavity is always filled with air. Since the air in the F-P cavity is compressed, the pressure in the F-P cavity increases, achieving internal and external pressure balance, reducing the influence of the internal and external pressure difference on the performance of the sensor, improving the pressure resistance of the sensor. At the same time, since the F-P cavity is always filled with air rather than water, the sensitivity is high. Description of the Drawings

[0037] Figure 1 It is a perspective structural schematic diagram of the microchannel type pressure-vibration composite optical fiber F-P sensor of the present invention.

[0038] Figure 2 It is a schematic diagram of the first structural layer of the present invention.

[0039] Figure 3 It is a schematic diagram of the second structural layer of the present invention.

[0040] Figure 4 It is a schematic diagram of the third structural layer of the present invention.

[0041] The reference numerals are as follows:

[0042] 1 - microchannel 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 Embodiments

[0043] The following will combine the drawings to detail the embodiments of the present invention to more clearly understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not a limitation to the scope of the present invention, but only to illustrate the essential spirit of the technical solution of the present invention.

[0044] As shown Figures 1 - 4 in the figure. A microchannel type pressure-vibration composite fiber optic F-P sensor of the present invention includes a first structural layer, a second structural layer, and a third structural layer that are sequentially laminated and bonded. The third structural layer includes a silicon wafer, on which a microchannel group 1, a water inlet hole 2, and an optical fiber channel hole are provided. The microchannel group 1 is located on one side of the silicon wafer, and the microchannel group 1 extends from the middle of the silicon wafer to the periphery. The water inlet hole 2 penetrates the silicon wafer and communicates with the microchannel group 1. The second structural layer includes a glass sheet, and a plurality of cavity holes are provided on the outer peripheral edge of the glass sheet. An optical fiber channel groove is also provided on the outer periphery of the glass sheet and communicates with a part of the corresponding cavity holes. One side of the glass sheet is bonded to one side of the silicon wafer so that one end of the cavity hole communicates with the outer periphery of the microchannel group 1, and one end of the optical fiber channel hole communicates with another part of the corresponding cavity holes. The first structural layer includes a silicon layer diaphragm, and one side of the silicon layer diaphragm is bonded to the other side of the glass sheet to seal the other end of the cavity hole, so that the cavity hole forms an F-P cavity, and a mass block is bonded in a part of the F-P cavity.

[0045] Specifically, the first structural layer, the second structural layer, and the third structural layer are sequentially bonded and connected into one body. Each cavity hole on the glass sheet forms an F-P cavity for detecting scalar and vector after being sealed by the silicon wafer and the silicon layer diaphragm. The optical fiber channel hole and the optical fiber channel groove are respectively used for inserting an optical fiber to conduct and transmit optical signals with the corresponding F-P cavity.

[0046] Before the sensor is put into water, the inside of the microchannel group 1 is air, and the pressure is normal atmospheric pressure. After being put into water, one side of the microchannel group 1 is atmospheric pressure, and the other side is water pressure. Due to the pressure difference that the water pressure is greater than the atmospheric pressure, the water flow is pushed into the microchannel group 1. At this time, the air on one side of the microchannel group 1 is compressed, and the pressure increases to the same as the water pressure, and the water will no longer flow. At the same time, part of the air in the microchannel group 1 is respectively pushed into the F-P cavity, thereby causing the pressure in the F-P cavity to increase, reducing the influence of the internal and external pressure difference on the performance of the sensor.

[0047] Furthermore, the microchannel group 1 is formed by a plurality of channels spirally sleeved, one end of the channel converges at the water inlet hole 2, and the other end of the channel extends toward the outer edge of the silicon wafer and communicates with the corresponding F-P cavity.

[0048] Specifically, in the present invention, the microchannel group 1 is composed of 4 "⺋"-shaped spiral channels sleeved. The number of channels is the same as the number of cavity holes. The inner ends of the 4 spiral channels converge at the water inlet hole 2 in the center of the silicon wafer. The 4 spiral channels are spirally unfolded from the water inlet hole 2. The outer ends of the 4 spiral channels are distributed and extend inside the outer peripheral edge of the silicon wafer. When the silicon wafer is bonded to the glass sheet, the outer ends of the 4 spiral channels are respectively communicated with the cavity holes distributed in an array on the glass sheet.

[0049] As an optimization, the microchannel group 1 is composed of a number of spiral channel loops. The length of each channel in the microchannel group 1 should be such that water will not flow into the mutually connected F-P cavities under the action of the pressure difference after entering the channels.

[0050] Furthermore, in order to simultaneously measure the scalar, X-axis component, Y-axis component, and Z-axis component, a number of cavities 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 penetrate the scalar cavity 8 and the Z-axis component cavity 5 vertically, and a pair of optical fiber channel grooves respectively penetrate the X-axis component cavity 6 and the Y-axis component cavity 7 horizontally.

[0051] Specifically, the X-axis component cavity 6 and the Y-axis component cavity 7 are respectively arranged at the mutually perpendicular two side edges at one end of the glass sheet. The edges of the X-axis component cavity 6 and the Y-axis component cavity 7 close to the glass sheet side are glass thin films. The scalar cavity 8 and the Z-axis component cavity 5 are respectively arranged inside the other end of the glass sheet. A pair of optical fiber channel holes are respectively a first optical fiber channel hole 3 and a second optical fiber channel hole 4. The first optical fiber channel hole 3 vertically penetrates the scalar cavity 8, and the second optical fiber channel hole 4 vertically penetrates the Z-axis component cavity 5. A pair of optical fiber channel grooves are respectively a first optical fiber channel groove 9 and a second optical fiber channel groove 13. Both the first optical fiber channel groove 9 and the second optical fiber channel groove 13 are of an L-shaped structure. One end of the first optical fiber channel groove 9 penetrates one side edge of the glass sheet, and the other end communicates with the X-axis component cavity 6. One end of the second optical fiber channel groove 13 penetrates one side edge of the glass sheet, and the other end communicates with the Y-axis component cavity 7. During measurement, optical fibers are inserted into the first optical fiber channel hole 3, the second optical fiber channel hole 4, the first optical fiber channel groove 9, and the second optical fiber channel groove 13.

[0052] By setting four F-P cavities in the present invention, after the microchannel group 1 is connected to the four F-P cavities, three of the F-P cavities are respectively used to measure the vibration signal components in the X-axis, Y-axis, and Z-axis directions, and one F-P cavity is used to measure the pressure scalar, achieving the purpose of pressure-vibration compounding.

[0053] Furthermore, in order to enhance the sensitivity of the sensor, adjust the frequency response characteristics, stability, and anti-interference ability, mass blocks are arranged in each component cavity. Among them, in order to improve the directivity of the cavity of the Z-axis component cavity 5 to sense 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. In order to improve the directivity of the cavities of the X-axis component cavity 6 and the Y-axis component cavity 7 to sense the X-axis vibration component and the Y-axis vibration component information respectively, 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. The side of the silicon layer diaphragm where the Z-axis mass block 12 is arranged is attached to the glass sheet to seal one end of the cavity.

[0054] Specifically, one side of the Z-axis mass block 12 is attached to and integrated with one side of the silicon layer diaphragm. After the silicon layer diaphragm and the glass sheet are bonded, the Z-axis mass block 12 is embedded at one end of the Z-axis component cavity 5 and spaced opposite to one end of 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 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 spaced opposite to one end of the second optical fiber channel groove 13.

[0055] 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. The glass films on one side of the X-axis component cavity 6 and the Y-axis component cavity 7 are respectively used to sense the X-axis vibration component and the Y-axis vibration component. Thus, the measurement of the vibration signal components can be carried out simultaneously from three directions of the X-axis, Y-axis, and Z-axis.

[0056] Furthermore, 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 communicated with the other ends of the corresponding flow channels. Water flows into different flow channels through the water inlet hole 2 to balance the internal and external pressures of the cavities of 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 magnitude of the pressure, ensuring that the pressure is balanced after the water enters the flow channel and does not enter each cavity.

[0057] A preparation method of a micro-channel type pressure-vibration composite optical fiber F-P sensor of the present invention includes the following steps:

[0058] Step 1: Preparation of the third structural layer, that is, first etching the micro-channel group 1 on one side surface of the silicon wafer, and then etching the water inlet hole 2 and a pair of optical fiber channel holes to form the third structural layer.

[0059] Specifically, the processing processes of the micro-channel group 1, the water inlet hole 2, and the optical fiber channel holes are the same.

[0060] First, select a double-polished single-crystal silicon wafer for cleaning. After cleaning, first process the micro-channel group 1 on the silicon wafer, and then process the water inlet hole 2 and the optical fiber channel holes. Taking the processing process of the micro-channel group 1 as an example for illustration.

[0061] The processing process of the micro-channel group 1 is as follows:

[0062] Step 101: Select photoresist as a mask, spin-coat the photoresist on the silicon wafer surface through a spin coater. After the spin coating of the photoresist is completed, perform soft baking on the silicon wafer with the spin-coated photoresist in a spin coating hot plate system to remove the solution in the photoresist and make the photoresist dry.

[0063] Step 102: Use the prepared microchannel group mask template to expose the unmasked surface of the silicon wafer, then place the lithographed silicon wafer in a developer for development, and place the developed silicon wafer on a spin coating hot plate system for heating to remove residual water and developer, forming a microchannel group etching window.

[0064] Step 103: Perform ICP etching on the microchannel group etching window to form the microchannel group 1.

[0065] Step 104: After the etching of the microchannel group 1 is completed, clean and remove the residual photoresist on the silicon wafer surface.

[0066] When processing the optical fiber channel holes and the water inlet holes 2 on the silicon wafer, the processing steps of the optical fiber channel holes and the water inlet holes 2 are the same as those of the microchannel group 1, the difference being that the optical fiber channel hole mask plate is used for the processing of the optical fiber channel holes, and the water inlet hole mask plate is used for the processing of the water inlet holes 2.

[0067] Step 2: Preparation of the second structural layer: That is, four cavity holes and a pair of optical fiber channel grooves are successively drilled on the glass sheet. The four cavity holes are successively the scalar cavity 8, the Z-axis component cavity 5, the X-axis component cavity 6, and the Y-axis component cavity 7. During the process of drilling the cavity holes, the X-axis mass block 10 is reserved in the X-axis component cavity 6, and the 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 first optical fiber channel groove 9 drilled horizontally penetrates the X-axis component cavity 6, and one end of the second optical fiber channel groove 13 drilled horizontally penetrates the Y-axis component cavity 7.

[0068] Specifically, it includes the following steps:

[0069] Step 201: Take a BF33 glass sheet, and use a glass drilling machine to drill four cavity holes on the glass sheet successively as the scalar cavity 8, the Z-axis component cavity 5, the X-axis component cavity 6, and the Y-axis component cavity 7. The scalar cavity 8 and the Z-axis component cavity 5 are arranged at intervals at one end inside the glass sheet, the X-axis component cavity 6 and the Y-axis component cavity 7 are located at the other end edge of the glass sheet, the X-axis mass block 10 is reserved on one side of the glass film in the X-axis component cavity 6, and the Y-axis mass block 11 is reserved on one side of the glass film in the Y-axis component cavity 7.

[0070] Step 202: Drill a pair of optical fiber channel grooves on one side surface of the glass sheet. When drilling, one end of the first optical fiber channel groove 9 penetrates the outer peripheral surface of the glass sheet, and the other end horizontally penetrates the X-axis component cavity 6 and is spaced opposite to the X-axis mass block 10. One end of the second optical fiber channel groove 13 penetrates the outer peripheral surface of the glass sheet, and the other end horizontally penetrates the Y-axis component cavity 7 and is spaced opposite to the Y-axis mass block 11.

[0071] Step 3: Etch the Z-axis mass block 12 on the silicon layer diaphragm to form the first structural layer.

[0072] Specifically, it includes the following steps:

[0073] Step 301: Select the device layer of the SOI wafer as the silicon layer diaphragm. The SOI wafer includes a device layer, a buried oxide layer, and a substrate layer from top to bottom.

[0074] Step 302: First, clean the SOI wafer, and coat a photoresist on one surface of the device layer of the SOI wafer as a mask for the Z-axis mass block area.

[0075] Then, use the prepared mask plate to cover the unmasked peripheral area of the Z-axis mass block and perform exposure to obtain an etching window for the peripheral area of the Z-axis mass block. Etch the device layer of the SOI wafer in the etching window of the peripheral area of the Z-axis mass block, and after etching, obtain the Z-axis mass block 12 on the surface of the device layer of the SOI wafer.

[0076] Step 303: After cleaning and removing the photoresist on the surface of the Z-axis mass block 12, obtain the first structural layer with a buried oxide layer and a substrate layer.

[0077] Step 4: Bond the first structural layer, the second structural layer, and the third structural layer in sequence, then remove the substrate layer and the buried oxide layer of the first structural layer, and finally perform dicing to obtain the sensor chip.

[0078] Specifically, it includes the following steps:

[0079] Step 401: Use a cleaning solution to clean the first structural layer, the second structural layer, and the third structural layer respectively to remove the surface residues of the first structural layer, the second structural layer, and the third structural layer, so that they all meet the bonding standard.

[0080] Step 402: Use a bonding machine to perform electrostatic bonding on the first structural layer, the second structural layer, and the third structural layer to form a bonded wafer.

[0081] Step 403: Etch off the substrate layer on the first structural layer of the bonded wafer through ICP etching to expose the buried oxide layer. Use a UV film to block the end portions of the optical fiber channel holes, water inlet holes, and optical fiber channel grooves on the bonded wafer, then immerse the bonded wafer in hydrofluoric acid to remove the buried oxide layer of the first structural layer, and after cleaning off the remaining hydrofluoric acid, dry the moisture with nitrogen to make the surface of the bonded wafer hydrophobic.

[0082] Step 404: Remove the UV film on the surface of the bonded wafer to obtain a whole-board chip; use a dicing machine to dice the whole-board chip to obtain the sensor chip.

[0083] When the present invention is encapsulated, four optical fibers are respectively inserted into the corresponding four F-P 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 vibration of the silicon layer diaphragm and the glass thin film of the sensor, resulting in a change in the cavity length of the F-P cavity of the sensor, causing changes in the interference signals between the reflected light from the optical fiber end face and the reflected light from the silicon layer diaphragm and the reflected light from the glass thin film respectively. By demodulating the four interference signals respectively, the information of pressure and three-direction vibration components can be obtained.

[0084] 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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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