Encapsulated echo wall mode bottle-shaped microcavity sound pressure sensor based on sound focusing enhancement

Abstract

The invention provides a packaged echo wall mode bottle-shaped microcavity sound pressure sensor based on sound focusing enhancement. The packaged echo wall mode bottle-shaped microcavity sound pressure sensor comprises a packaging substrate, an echo wall mode bottle-shaped microcavity, an optical fiber pyrometric cone and an acoustic focusing lens, wherein the optical fiber pyrometric cone and the bottle-shaped microcavity form a coupling system, and the thinnest part of the cone region of the optical fiber pyrometric cone is coupled with the equatorial plane of the bottle-shaped microcavity; the bottle-shaped micro-cavity is provided with a micro-cavity body, a long handle and a short handle, one end of the long handle and one end of the short handle are respectively connected with the micro-cavity body, the other end of the long handle and the two ends of the optical fiber pyrometric cone are fixed on the packaging substrate, and the other end of the short handle is suspended; the acoustic focusing lens is provided with a hollow structure, covers the coupling system and fixedly covers the upper surface of the packaging substrate, so that a sound pressure focusing structure is formed. The two ends of the optical fiber pyrometric cone are fixed, and only one long-handle end of the echo wall mode bottle-shaped microcavity is fixed, so that a cantilever beam structure is formed. The sound pressure sensor can realize ultrahigh sensitive sound pressure sensing.

Description

Technical Field

[0001] This invention patent relates to the field of acoustic wave measurement, and specifically relates to a packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement. Background Art

[0002] As a core device for acoustic signal detection, acoustic pressure sensors have important applications in fields such as ocean exploration, medical ultrasonic imaging, and industrial non-destructive testing. Traditional sensors mainly rely on piezoelectric ceramics or capacitive principles, and their sensitivity is limited by the electromechanical conversion efficiency of materials and is vulnerable to environmental electromagnetic interference, resulting in a significant decrease in the signal-to-noise ratio in complex environments. Fiber optic sensors based on optical microcavities have the advantages of anti-electromagnetic interference, small size, and high sensitivity, and are regarded as the key path to break through traditional bottlenecks. Among them, whispering gallery mode microcavity sensors localize the optical field within the micron scale through total internal reflection, and theoretically can achieve ultra-high quality factors and sensitivities. However, in order to excite the whispering gallery mode in the whispering gallery mode microcavity, it is necessary to use a fiber optic taper to couple light into the microcavity. The taper region of the fiber optic taper is only 1 - 2 μm, and its fragility and the instability of the coupling system seriously hinder the application of whispering gallery mode bottle-shaped microcavities in the field of acoustic sensing. Therefore, developing an acoustic pressure sensor with both high sensitivity and long-term stability still faces severe challenges. Summary of the Invention

[0003] To solve the above problems, the present invention proposes a packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement. Through the local acoustic pressure amplification of the acoustic focusing lens and the ultra-high quality factor of the whispering gallery mode bottle-shaped microcavity, ultra-high sensitivity acoustic pressure sensing can be achieved.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement, comprising a packaging substrate, a whispering gallery mode bottle-shaped microcavity, a fiber optic taper, and an acoustic focusing lens; wherein, the fiber optic taper and the bottle-shaped microcavity form a coupling system, and the thinnest part of the taper region of the fiber optic taper is coupled to the equatorial plane of the bottle-shaped microcavity; the bottle-shaped microcavity has a microcavity body, a long handle, and a short handle. One end of the long handle and one end of the short handle are respectively connected to the microcavity body. The other end of the long handle and the two ends of the fiber optic taper are fixed on the packaging substrate, and the other end of the short handle is suspended; the acoustic focusing lens has a hollow structure, covers the coupling system, and is fixedly covered on the upper surface of the packaging substrate. This design constitutes an acoustic pressure focusing structure and plays a role in protecting the coupling system of the fiber optic taper and the bottle-shaped microcavity.

[0006] Among them, there is a coupling distance of sub-micron level (preferably 0.5 - 1 μm) between the fiber optic taper and the bottle-shaped microcavity. The position of the focus of the acoustic focusing lens matches that of the bottle-shaped microcavity, which is used to focus and amplify the acoustic pressure signal. When the acoustic focusing lens is applied with an acoustic pressure signal of a certain frequency and amplitude, it focuses the acoustic pressure signal onto the bottle-shaped microcavity, causing the bottle-shaped microcavity to vibrate, resulting in a change in the coupling distance between the fiber optic taper and the bottle-shaped microcavity. Acoustic pressure sensing is achieved by detecting this distance change. The acoustic focusing frequency of the acoustic focusing lens can be flexibly designed according to requirements.

[0007] Among them, one end of the long handle and one end of the short handle are respectively connected to the microcavity body. The other end of the long handle is fixed on the packaging substrate, and the other end of the short handle is suspended. In this way, the bottle-shaped microcavity with one end fixed forms a cantilever beam structure. The thinnest part of the taper region of the fiber optic taper is coupled with the equatorial plane of the bottle-shaped microcavity to excite the high-quality factor whispering gallery mode. On the one hand, the structural design of the present invention realizes the efficient excitation of the whispering gallery mode through precise control of optical field coupling. On the other hand, the bottle-shaped microcavity has a mechanical sensitivity amplification function through the cantilever beam structure, thereby enhancing its response sensitivity to the acoustic pressure signal. The whispering gallery mode bottle-shaped microcavity cantilever beam structure is used as a transducer. The acoustic wave signal is focused onto the bottle-shaped microcavity by the acoustic focusing lens, causing mechanical vibration. The up and down vibration of the bottle-shaped microcavity cantilever beam leads to a change in the coupling distance between it and the fiber optic taper, changing the coupling loss of the whispering gallery mode, thereby causing a change in the spectrum.

[0008] According to an embodiment of the present invention, two vertically intersecting grooves are engraved on one side surface of the packaging substrate to respectively place the bottle-shaped microcavity and the fiber optic taper. Optionally, the packaging substrate is etched from a thick quartz wafer by a multi-laser integrated additive / subtractive manufacturing technology.

[0009] Optionally, the other end of the long handle is fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology.

[0010] Optionally, both ends of the fiber optic taper are fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology.

[0011] Optionally, the acoustic focusing lens is fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology.

[0012] Preferably, the material used in the multi-laser integrated additive / subtractive manufacturing technology is quartz material.

[0013] According to an embodiment of the present invention, the fiber optic taper is made by fusing and tapering a single-mode fiber, and the diameter of the thinnest part of the taper region of the fiber optic taper is 1 - 2 μm.

[0014] Preferably, the coupling distance between the thinnest part of the tapered region of the fiber taper and the equatorial plane of the bottle-shaped microcavity is 0.5 - 1 μm.

[0015] As needed, the packaging substrate can be in structures such as circular, square, triangular, etc., and just needs to match the acoustic focusing lens. Correspondingly, the acoustic focusing lens can be selected in structures such as circular, square, triangular, etc.

[0016] Preferably, the material of the acoustic focusing lens is quartz.

[0017] Optionally, the acoustic focusing lens is a Fresnel type acoustic focusing lens or a sharp-edge aperture acoustic focusing lens.

[0018] Preferably, the whole of the acoustic pressure sensor is encapsulated with all quartz and has characteristics such as high temperature resistance and corrosion resistance. The materials of the packaging substrate and the acoustic focusing lens are both quartz.

[0019] The radius of the equatorial plane is usually on the order of micrometers, the length of the long handle is on the order of centimeters, and the length of the short handle is on the order of millimeters or centimeters.

[0020] A preparation method of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement as described above includes the following steps:

[0021] (1) Fix both ends of the fiber taper on the packaging substrate.

[0022] (2) Place the bottle-shaped microcavity in the packaging substrate and adjust the position to couple the thinnest part of the tapered region of the fiber taper with the equatorial plane of the bottle-shaped microcavity.

[0023] (3) Fix the long handle of the bottle-shaped microcavity on the packaging substrate.

[0024] (4) Adjust the position matching between the focus of the acoustic focusing lens and the bottle-shaped microcavity, and then fix and cover the acoustic focusing lens on the upper surface of the packaging substrate.

[0025] Specifically, a preparation method of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement includes the following steps:

[0026] (1) Process two perpendicular grooves on one side surface of the quartz substrate to form the packaging substrate.

[0027] (2) Pre-place the fiber taper in one groove and encapsulate both ends through multi-laser integrated additive / subtractive manufacturing technology.

[0028] (3) Place the bottle-shaped microcavity in the other groove and adjust the position to couple its equatorial plane with the fiber taper, and the coupling distance is 0.5 - 1 μm.

[0029] (4) The bottle-shaped microcavity has a microcavity body and a long handle. One end of the long handle is connected to the microcavity body, and the other end of the long handle is fixed in the groove by multi-laser integrated additive / subtractive manufacturing technology, forming a cantilever beam structure.

[0030] (5) The acoustic focusing lens is welded to the upper surface of the substrate by multi-laser integrated additive / subtractive manufacturing technology to complete the encapsulation.

[0031] The advantages of the present invention compared with the existing whispering gallery mode microcavity acoustic pressure sensor are as follows:

[0032] The whispering gallery mode bottle-shaped microcavity has excellent three-dimensional light confinement ability, supporting not only the radial WGM that circulates around the equator but also the axial WGM that propagates in a spiral along the axis, and showing high tolerance to the angular misalignment of the light excitation system.

[0033] The acoustic pressure signal is locally amplified by a specially designed acoustic focusing lens, thereby increasing the effect of the acoustic pressure on the cantilever beam structure of the bottle-shaped microcavity and improving the sensitivity of acoustic pressure sensing.

[0034] The all-quartz encapsulation enhances the stability of the coupling system between the whispering gallery mode bottle-shaped microcavity and the optical fiber, avoids the optical fiber taper from being damaged by external influences, and makes the entire sensor become an all-quartz acoustic pressure focusing structure. At the same time, the all-quartz structure endows the acoustic pressure sensor with high physical and chemical stability and can be used in harsh environments such as high temperature, high pressure, high acidity / alkalinity, and high electromagnetic interference. Description of the Drawings

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of an encapsulated whispering gallery mode bottle-shaped microcavity acoustic pressure sensor in an embodiment;

[0037] Figures 2(a), 2(b), and 2(c) are respectively schematic structural diagrams of an encapsulated substrate, a whispering gallery mode bottle-shaped microcavity optical fiber taper coupling system, and an acoustic focusing lens (Fresnel type acoustic focusing lens) in an embodiment; Figure 2(d) is a schematic structural diagram of an acoustic focusing lens (sharp-edge aperture acoustic focusing lens) in another embodiment;

[0038] Figure 3Mechanical deformation diagram of the whispering gallery mode bottle-shaped microcavity cantilever beam structure of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement in Embodiment 1;

[0039] Figure 4 is the acoustic focusing effect diagram of the acoustic focusing lens of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement in Embodiment 1;

[0040] Figure 5 Transmission spectrum diagram of the acoustic pressure sensor of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement in Embodiment 1;

[0041] Figure 6 Displacement change diagram at the coupling of the whispering gallery mode bottle-shaped microcavity of the acoustic pressure sensor with / without an acoustic focusing lens under different acoustic pressures;

[0042] In the figure: 1 - whispering gallery mode bottle-shaped microcavity; 11 - microcavity body; 12 - long handle; 13 - short handle; 2 - packaging substrate; 21 - groove; 3 - packaging fixing block; 4 - fiber optic taper; 5 - acoustic focusing lens. Specific implementation manners

[0043] In order to more clearly illustrate the features and technical content of the embodiments of the present invention application, the embodiments of the present invention application will be described below with reference to the accompanying drawings.

[0044] Figure 1FIG. 0 is a schematic structural diagram of an embodiment of a packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to the present invention. The sensor mainly consists of a whispering gallery mode bottle-shaped microcavity 1, a packaging substrate 2, a packaging fixing block 3, an optical fiber taper 4, and an acoustic focusing lens 5. The optical fiber taper 4 and the whispering gallery mode bottle-shaped microcavity 1 form a coupling system, and the thinnest part of the taper region of the optical fiber taper 4 is coupled to the equatorial plane of the whispering gallery mode bottle-shaped microcavity 1. The whispering gallery mode bottle-shaped microcavity 1 has a microcavity body 11, a long handle 12, and a short handle 13. The equatorial plane radius of the microcavity body 11 is usually on the order of micrometers, the length of the long handle 12 is generally on the order of centimeters, and the length of the short handle 13 is generally on the order of millimeters or centimeters. One end of the long handle 12 and both ends of the optical fiber taper 4 are fixed on the packaging substrate 2. The other end of the long handle 12 is connected to the microcavity body 11. One end of the short handle 13 is connected to the microcavity body 11, and the other end of the short handle 13 is suspended. The packaging substrate 2 is made of quartz, and its shape is not limited to a circle. Two vertically intersecting grooves 21 are engraved on one side surface of the packaging substrate 2, which are prepared by a multi-laser integrated additive / subtractive manufacturing technique, and the shape is not limited. The packaging fixing block 3 is a connecting structure formed by a multi-laser integrated additive / subtractive manufacturing technique, which seamlessly fixes one end of the long handle 12 of the bottle-shaped microcavity and both ends of the optical fiber taper 4 on the packaging substrate 2. The optical fiber taper 4 is made by melting and tapering a single-mode optical fiber. The acoustic focusing lens 5 has a hollow structure, covers the coupling system, and is fixedly covered on the upper surface of the packaging substrate 2. Through the above structural design, a sensor with an acoustic pressure focusing structure is formed, and the stability of the coupling system between the optical fiber taper and the bottle-shaped microcavity is improved. The acoustic focusing lens 5 can be of types such as a Fresnel type acoustic focusing lens, a sharp-edge aperture acoustic focusing lens, etc.

[0045] Specifically, as shown in FIG. 2(a), two vertically intersecting grooves 21 are engraved on the packaging substrate 2 to respectively place the whispering gallery mode bottle-shaped microcavity and the optical fiber taper, and the shape of the grooves is not limited to a rectangle. As shown in FIG. 2(b), the whispering gallery mode bottle-shaped microcavity 1 and the optical fiber taper 4 are placed vertically. The whispering gallery mode bottle-shaped microcavity 1 has a microcavity body 11, a long handle 12, and a short handle 13. The equatorial plane of the bottle-shaped microcavity 1 is coupled to the thinnest part of the taper region of the optical fiber taper 4, and has a coupling distance of 0.5 - 1 μm. FIGS. 2(c) and 2(d) are respectively schematic structural diagrams of a Fresnel type acoustic focusing lens and a sharp-edge aperture acoustic focusing lens.

[0046] The present invention provides an all - quartz packaged whispering - gallery - mode bottle - shaped micro - cavity acoustic pressure sensor based on acoustic focusing enhancement, which mainly consists of a whispering - gallery - mode bottle - shaped micro - cavity 1, a packaging substrate 2, an optical fiber taper 4, and an acoustic focusing lens 5. Through the multi - laser integrated additive / subtractive manufacturing technology, one end of the long handle of the whispering - gallery - mode bottle - shaped micro - cavity 1 is fixed in the groove of the packaging substrate 2 to form a cantilever beam structure as an acoustic pressure transducer. The optical fiber taper 4 is fixed at both ends in another set of grooves of the packaging substrate 1 and is coupled with the bottle - shaped micro - cavity 1 to excite its whispering - gallery mode. Meanwhile, a coupling distance of 0.5 - 1 μm is preset between them. The acoustic focusing lens 5 is combined with the packaging substrate 2 through the multi - laser integrated additive / subtractive manufacturing technology to locally amplify the acoustic pressure, making the whole sensor an acoustic pressure focusing structure and playing a role in protecting the coupling system of the optical fiber taper and the bottle - shaped micro - cavity. When the acoustic pressure acts on the acoustic focusing lens 5, the acoustic signal is focused on the bottle - shaped micro - cavity 1 to achieve local amplification and drive the cantilever beam structure to vibrate, thereby changing the coupling distance. By detecting the intensity change of the resonance peak caused by the coupling distance, high - sensitivity detection of the acoustic pressure can be realized. In addition, the whispering - gallery - mode bottle - shaped micro - cavity 1, the packaging substrate 2, the optical fiber taper 4, and the acoustic focusing lens 5 adopt an all - quartz structure, and all - quartz packaging is realized through the multi - laser integrated additive / subtractive manufacturing technology, making the acoustic pressure sensor have high physical and chemical stability and can be used in harsh environments such as high temperature, high pressure, high acidity / alkalinity, and high electromagnetic interference.

[0047] Example 1

[0048] A preparation method of an all - quartz packaged whispering - gallery - mode bottle - shaped micro - cavity acoustic pressure sensor based on acoustic focusing enhancement includes the following steps:

[0049] (1) Process two perpendicular grooves on one side surface of a quartz substrate to form a packaging substrate;

[0050] (2) Place the optical fiber taper in one groove and package both ends through the multi - laser integrated additive / subtractive manufacturing technology;

[0051] (3) Place the bottle - shaped micro - cavity in the other groove and adjust its position so that its equatorial plane is coupled with the optical fiber taper, and the coupling distance is 0.5 - 1 μm;

[0052] (4) The bottle - shaped micro - cavity has a micro - cavity body and a long handle. One end of the long handle is connected to the micro - cavity body, and the other end of the long handle is fixed in the groove through the multi - laser integrated additive / subtractive manufacturing technology to form a cantilever beam structure;

[0053] (5) Weld the acoustic focusing lens to the upper surface of the substrate through the multi - laser integrated additive / subtractive manufacturing technology to complete the packaging.

[0054] The optical fiber fused taper mentioned above is made by fusing and tapering a single-mode optical fiber, and the diameter of the tapered region is 1 - 2 μm. The outer diameter of the cladding of the single-mode optical fiber used is 125 ± 0.7 μm, and the core diameter is 10.4 ± 0.5 μm. The acoustic focusing lens mentioned above is a Fresnel-type acoustic focusing lens, with a thickness of 0.5 mm and a radius on the order of centimeters. The material used in the multi-laser integrated additive / subtractive manufacturing technology is quartz material.

[0055] The schematic diagram of the sensor structure prepared by the above method is as Figure 1 shown. The following experiments are carried out on this sensor.

[0056] Figure 3 This is the mechanical simulation of the bottle-shaped microcavity cantilever beam structure by COMSOL multi-physics simulation software. A boundary load with a pressure of 1 Pa is applied to the upper surface of the convex part of the microcavity of the bottle-shaped microcavity, and the deformation diagram of the corresponding structure is obtained.

[0057] The sensitivity of the cantilever beam structure is related to the displacement of the free end of the cantilever beam. The larger the displacement, the greater the change in the coupling distance, and the greater the change in the intensity of the transmission spectrum resonance peak.

[0058] Solve for the displacement change of the free end of the cantilever beam. The frequency response A(ω) of the free end of the cantilever beam can be expressed as:

[0059]

[0060] where ω is the angular frequency, ω0 is the frequency of the acoustic signal applied to the surface of the cantilever beam, F0 is the pressure applied to the surface of the cantilever beam, m represents the effective mass of the cantilever beam, and D represents the damping coefficient; this formula shows that the frequency response is related to the magnitude of the acoustic signal frequency. When the applied signal frequency matches the frequency of the cantilever beam itself, the frequency response can reach the maximum.

[0061] Figure 4 is the simulation diagram of the acoustic focusing effect achieved by the acoustic focusing lens through COMSOL multi-physics simulation software. Through the acoustic-solid multi-physics coupling condition, the four peripheral boundaries of the acoustic focusing lens are set as fixed constraints, the surrounding boundaries are set as perfectly matched boundaries, and the sound source is set as the background pressure field with a sound pressure of 1 Pa and a frequency of 50 kHz, and the focusing effect of the acoustic focusing lens 5 in the sound field is obtained. It can be clearly seen from Figure 4(a) that there is a point with a maximum sound pressure value below the center of the acoustic focusing lens 5. Figure 4(b) shows that this point is located about 4.14 mm below the center, and the sound pressure is close to 3 Pa, which is about 3 times larger than the incident sound pressure. The greater the pressure, the greater the displacement of the cantilever beam, and the higher the sensitivity of the sound pressure sensor.

[0062] Figure 5 This is the transmission spectrum diagram of the packaged whispering gallery mode bottle-shaped microcavity sound pressure sensor based on acoustic focusing enhancement described in this embodiment. As Figure 5As shown, the whispering gallery mode resonance peak in the spectrogram is of Lorentzian line shape, with a half-wave bandwidth on the order of picometers, and the narrowest resonance peak has a quality factor as high as 7×10 7 .

[0063] Figure 6 Figure is a comparison diagram of the displacement at the coupling of the whispering gallery mode bottle-shaped microcavity with and without an acoustic focusing lens. As Figure 6 can be seen, as the applied acoustic pressure increases, the displacement of the whispering gallery mode bottle-shaped microcavity increases accordingly. After adding the acoustic focusing lens, at the same acoustic pressure, the displacement of the whispering gallery mode bottle-shaped microcavity increases by more than twice.

Claims

1. An encapsulated whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement, characterized in that It includes a packaging substrate, a whispering gallery mode bottle-shaped microcavity, an optical fiber taper, and an acoustic focusing lens. Among them, the optical fiber taper and the bottle-shaped microcavity form a coupling system, and the thinnest part of the taper region of the optical fiber taper is coupled to the equatorial plane of the bottle-shaped microcavity. The bottle-shaped microcavity has a microcavity body, a long handle, and a short handle. One end of the long handle and one end of the short handle are respectively connected to the microcavity body. The other end of the long handle and the two ends of the optical fiber taper are fixed on the packaging substrate, and the other end of the short handle is suspended. The acoustic focusing lens has a hollow structure, covers the coupling system, and is fixedly covered on the upper surface of the packaging substrate.

2. The packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 1, wherein Two vertically intersecting grooves are engraved on one side surface of the packaging substrate to respectively place the bottle-shaped microcavity and the optical fiber taper.

3. The encapsulated whispering-gallery-mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 2, characterized in that, The packaging substrate is etched from a thick quartz wafer by a multi-laser integrated additive / subtractive manufacturing technology.

4. The encapsulated whispering gallery mode bottle-shaped microcavity sound pressure sensor based on acoustic focusing enhancement according to claim 1, wherein The other end of the long handle is fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology; the two ends of the optical fiber taper are fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology; The acoustic focusing lens is fixed on the packaging substrate by a multi-laser integrated additive / subtractive manufacturing technology.

5. The packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 1, characterized in that, The optical fiber taper is made by melting and tapering a single-mode optical fiber, and the diameter of the thinnest part of the taper region of the optical fiber taper is 1-2 μm.

6. The encapsulated whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 1, wherein The coupling distance between the thinnest part of the taper region of the optical fiber taper and the equatorial plane of the bottle-shaped microcavity is 0.5-1 μm.

7. The encapsulation whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 1, characterized in that, The material of the acoustic focusing lens is quartz.

8. The packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 1, characterized in that, The acoustic focusing lens is a Fresnel type acoustic focusing lens or a sharp-edge aperture acoustic focusing lens.

9. A method for preparing an encapsulated whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to any one of claims 1-8, characterized in that, It includes the following steps: (1) Fix the two ends of the optical fiber taper on the packaging substrate, (2) Place the bottle-shaped microcavity in the packaging substrate and adjust the position to couple the thinnest part of the taper region of the optical fiber taper to the equatorial plane of the bottle-shaped microcavity; (3) Fix the long handle of the bottle-shaped microcavity on the packaging substrate; (4) Adjust the position of the focus of the acoustic focusing lens to match that of the bottle-shaped microcavity, and then fix and cover the acoustic focusing lens on the upper surface of the packaging substrate.

10. The preparation method of the packaged whispering gallery mode bottle-shaped microcavity acoustic pressure sensor based on acoustic focusing enhancement according to claim 9, characterized in that, It includes the following steps: (1) Process two perpendicular grooves on one side surface of a quartz substrate to form a packaging substrate; (2) Place the optical fiber taper in one groove and package the two ends by a multi-laser integrated additive / subtractive manufacturing technology; (3) Place the bottle-shaped microcavity in the other groove and adjust the position to couple its equatorial plane with the optical fiber taper, and the coupling distance is 0.5-1 μm; (4) The bottle-shaped microcavity has a microcavity body and a long handle. One end of the long handle is connected to the microcavity body, and the other end of the long handle is fixed in the groove by a multi-laser integrated additive / subtractive manufacturing technology to form a cantilever beam structure; (5) Use a multi-laser integrated additive / subtractive manufacturing technology to weld the acoustic focusing lens to the upper surface of the substrate to complete the packaging.

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