Chiral mechanical superstructures, fiber optic accelerometers and their fabrication methods

Abstract

This invention discloses a chiral mechanical superstructure, a fiber optic accelerometer, and a method for fabricating the same. The fiber optic accelerometer includes the chiral mechanical superstructure and an optical fiber. The chiral mechanical superstructure includes a support base, at least one support column disposed on the side of the upper end face of the support base, elastic connecting rods disposed at the upper ends of each support column, at least two chiral helical cantilever beams connected to the upper ends of the support columns via the elastic connecting rods, and a central mass block located above the support base and at the center of the area enclosed by each chiral helical cantilever beam. Each chiral helical cantilever beam is centrally symmetrically distributed with respect to the central mass block. The outer end of each chiral helical cantilever beam is connected to each of the elastic connecting rods, and the other end of each chiral helical cantilever beam is connected to the central mass block. This invention provides a fiber optic accelerometer based on the chiral mechanical superstructure that is resistant to electromagnetic interference, small in size, low in power consumption, and high in measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of optical sensing technology, and more particularly to a chiral mechanical superstructure, a fiber optic accelerometer, and a method for fabricating the same. Background Technology

[0002] Accelerometers are fundamental components in motion and vibration sensing systems such as consumer electronics, navigation, and seismology.

[0003] Existing silicon-based MEMS accelerometers face a fundamental physical trade-off between sensitivity and miniaturization. To improve resolution, the mass of the mass block must be increased and the spring stiffness reduced. This inevitably leads to increased sensor size, increased complexity in manufacturing precision springs, and sacrifices shock resistance. Meanwhile, the fabrication and design verification cycles are long, and the pace of iteration is slow. Current technology significantly limits further miniaturization of high-performance sensors.

[0004] Existing optical accelerometers, such as those based on optical tweezers, photonic crystals, or interferometers, while offering advantages in high precision and resistance to electromagnetic interference, heavily rely on discrete components and sophisticated physical packaging, resulting in bulky devices. In recent years, attempts have been made to fabricate fiber optic accelerometers using 3D printing technologies such as digital light processing (DLP). However, the processing precision of these 3D printing technologies is limited (only reaching the 30-50 μm level), far from meeting the sub-micron feature size requirements of high-performance micro / nano optical accelerometers.

[0005] Existing quasi-zero stiffness (QZS) technology: QZS can bring dynamic stiffness close to zero near the equilibrium position, thereby improving sensitivity without increasing volume. However, existing QZS implementations, such as inclined springs, curved beams, electrostatically adjustable anti-springs, and electromagnetic biasing, all rely on complex physical assembly of multiple components or external energy sources (such as electromagnetic actuator control). They essentially achieve QZS through component-level force balancing, rather than through inherent structural properties, resulting in drawbacks such as large size, susceptibility to interference, increased power consumption, and extremely difficult assembly.

[0006] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a chiral mechanical superstructure, a fiber optic accelerometer and its fabrication method, to solve the problems of existing accelerometers being large in size, high in power consumption, susceptible to interference, complex and long in fabrication process, and low in measurement accuracy.

[0008] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a chiral mechanical superstructure, comprising: a support base, at least one support column disposed on the side of the upper end face of the support base, elastic connecting rods disposed at the upper ends of each of the support columns, at least two chiral helical cantilever beams connected to the upper ends of the support columns via the elastic connecting rods, and a central mass block located above the support base and at the center of the area surrounded by each of the chiral helical cantilever beams; each of the chiral helical cantilever beams has a helical shape with the same direction of rotation; each of the chiral helical cantilever beams is centrally symmetrically distributed with respect to the central mass block; the outer end of each chiral helical cantilever beam is connected to each of the elastic connecting rods, and the other end of each chiral helical cantilever beam is connected to the central mass block; the central mass block is suspended and supported above the support base, and has a predetermined vertical distance between it and the support base.

[0009] In a further embodiment of the present invention, each of the chiral helical cantilever beams is an annular strip structure, and the chiral helical cantilever beams are arranged in a concentric nested manner.

[0010] In a further embodiment of the present invention, the chiral mechanical superstructure also includes an auxiliary developing structure, which comprises several pads of the same size, evenly distributed on the support base.

[0011] Secondly, the present invention provides an optical fiber accelerometer, comprising: the aforementioned chiral mechanical superstructure and an optical fiber; the support base is fixed to the top of the optical fiber, the support base is hollow, the central mass block is suspended and supported above the optical fiber, and the lower surface of the central mass block and the end face of the optical fiber form a Fabry-Perot interferometer microcavity.

[0012] In a further embodiment of the present invention, the optical fiber is a single-mode optical fiber.

[0013] In a further embodiment of the present invention, the chiral mechanical superstructure is printed on top of the fiber cladding of the optical fiber via additive manufacturing.

[0014] Thirdly, the present invention provides a method for fabricating an optical fiber accelerometer, wherein the chiral mechanical superstructure is realized by digital light processing, nanoimprinting, or multilayer photolithography combined with deep silicon etching or electron beam etching and fixed on the top cross section of the optical fiber.

[0015] Fourthly, the present invention provides a method for fabricating an optical fiber accelerometer, comprising: dropping photoresist onto the window of an objective lens and immersing the end face of an optical fiber in the photoresist; using two-photon polymerization technology, focusing a femtosecond laser through the objective lens onto the inside of the photoresist, using the end face of the optical fiber as the processing base, scanning and curing the photoresist to print a chiral mechanical superstructure; placing the chiral mechanical superstructure in a solvent for wet development; after the photoresist dissolves, the central mass block is lifted under the action of the intrinsic elastic restoring force of the chiral helical cantilever beam, detaching from the support base, thereby achieving self-release from suspension.

[0016] In a further embodiment of the present invention, the solvent is propylene glycol methyl ether acetate.

[0017] A further feature of the present invention includes an auxiliary developing structure integrally printed on the support base.

[0018] The present invention provides a chiral mechanical superstructure, a fiber optic accelerometer, and its fabrication method, which have the following advantages: The fiber optic accelerometer based on the chiral mechanical superstructure of this invention abandons the traditional multi-component force balance mechanism. It utilizes a chiral helical cantilever beam with chiral directional characteristics and the resulting pressure-torsional coupling mechanical effect for measurement. The fiber optic accelerometer based on the chiral mechanical superstructure of this invention is resistant to electromagnetic interference, has a small size, low power consumption, a simple fabrication method with a short manufacturing and assembly cycle, high processing accuracy, and high measurement accuracy. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a chiral mechanical superstructure in one embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of an optical fiber accelerometer in one embodiment of the present invention.

[0022] Figure 3 This is a flowchart of a fiber optic accelerometer fabrication method in one embodiment of the present invention.

[0023] Figure 4 This is a diagram showing the relationship between the theory and experimental simulation of the normalized elastic restoring force generated by a chiral mechanical superstructure under axial displacement in one embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the principle of a Fabry-Perot interference microcavity constructed in one embodiment of the present invention.

[0025] Figure 6 This is a load-displacement stiffness control curve of a fiber optic accelerometer under different numbers of chiral helical cantilever beams in one embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram illustrating the mechanical decomposition principle of a chiral mechanical superstructure in one embodiment of the present invention.

[0027] Figure 8 This is an equivalent acceleration noise curve of a fiber optic accelerometer in one embodiment of the present invention and a resolution comparison diagram with other types of accelerometers.

[0028] Reference numerals: 1-optical fiber, 2-support base, 3-auxiliary developing structure, 4-support column, 5-elastic connecting rod, 6-chiral spiral cantilever beam, 7-central mass block. Detailed Implementation

[0029] This invention provides a chiral mechanical superstructure, a fiber optic accelerometer, and a method for fabricating the same. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of the present invention involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0031] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0032] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0033] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0034] Please refer to the instruction manual appendix. Figure 1 This invention provides a preferred embodiment of a chiral mechanical superstructure, comprising: a support base 2; at least one support column 4 disposed on the side of the upper end face of the support base 2; elastic connecting rods 5 disposed on the upper ends of each of the support columns 4; at least two chiral helical cantilever beams 6 connected to the upper ends of the support columns 4 via each of the elastic connecting rods 5; and a central mass block 7 located above the support base 2 and at the center of the area surrounded by each of the chiral helical cantilever beams 6; each of the chiral helical cantilever beams 6 has a helical shape with the same direction of rotation; each of the chiral helical cantilever beams 6 is centrally symmetrically distributed with respect to the central mass block 7; the outer end of each chiral helical cantilever beam 6 is connected to each of the elastic connecting rods 5, and the other end of each chiral helical cantilever beam 6 is connected to the central mass block 7; the central mass block 7 is suspended above the support base 2 and has a predetermined vertical distance between it and the support base 2.

[0035] When this chiral superstructure is subjected to external Z-axis (axial) inertial acceleration or gravitational load, the central mass block undergoes downward displacement. Due to the chiral characteristics of the structure, the out-of-plane compressive force is converted into in-plane (XY plane) torsional deformation through the chiral helical cantilever beam. This "compression-torsion coupling," under microscale displacement (≤1000nm), subjects the elastic connecting rod to torque and bending moment, offsetting part of the system's elastic restoring force, thus exhibiting quasi-zero stiffness characteristics. For example... Figure 4 The figure shown is a diagram relating the normalized elastic restoring force generated by the chiral mechanical superstructure under axial displacement in an embodiment of the present invention to the theory and experimental simulation. Figure 7 This is a schematic diagram illustrating the mechanical decomposition principle of the chiral mechanical superstructure in this embodiment.

[0036] A preferred embodiment of the fiber optic accelerometer of the present invention, such as... Figure 2As shown, the fiber optic accelerometer of the present invention includes: a chiral mechanical superstructure and an optical fiber 1; the supporting base 2 is fixed to the top of the optical fiber 1, the supporting base 2 is hollow, and the central mass block 7 is suspended above the optical fiber 1, with the lower surface of the central mass block 7 and the end face of the optical fiber forming a Fabry-Perot interferometer microcavity. The principle of the Fabry-Perot interferometer microcavity is as follows: Figure 5 As shown.

[0037] This invention, based on a chiral mechanical metastructure, abandons the traditional multi-component force balance mechanism in fiber optic accelerometers. Instead, it designs a chiral mechanical metastructure that utilizes its own geometry to generate a compression-twist coupling effect. This chiral mechanical metastructure is integrated in situ at the top of the fiber to construct a Fabry-Perot interferometer (FPI), achieving a high signal-to-noise ratio and electromagnetic interference-free conversion of sub-nanometer mechanical displacement into optical intensity signals. In this fiber optic accelerometer, the interferometer based on the Fabry-Perot microcavity detects the minute changes in the distance between the fiber end face and the reflecting surface (the lower surface of the central mass block) (this distance constitutes an FP cavity) to deduce the acceleration applied to the fiber optic accelerometer.

[0038] This fiber optic accelerometer overcomes the trade-off between size and sensitivity: relying on a single geometric configuration (requiring no external bias or multi-component assembly), it achieves intrinsic quasi-zero stiffness in situ, with structural stiffness as low as 0.012 N / m. This enables the fiber optic accelerometer to reach 9.98 µg Hz at the micrometer scale. -1 / 2 Its ultra-high resolution, with a size only a few thousandths of that of traditional high-sensitivity optical sensors, such as... Figure 8 As shown.

[0039] In this embodiment of the invention, the overall chiral superstructure is additively printed onto the top of the fiber cladding of a single-mode optical fiber. A support base is disposed on top of the fiber cladding. Additive manufacturing refers to a method of constructing a three-dimensional object by layer-by-layer deposition of material based on three-dimensional model data. Therefore, the chiral superstructure provided by this invention has high reliability and toughness. Due to the use of polymer and spring-like geometry, this chiral superstructure possesses elastic recovery force after undergoing extreme overload deformation and is not prone to brittle fracture like silicon-based cantilever beams.

[0040] In one possible implementation, such as Figure 2 As shown, the chiral mechanical superstructure also includes an auxiliary development structure 3, which comprises several identically sized pads evenly distributed on the support base. The auxiliary development structure 3 is used to prevent the central mass block from directly contacting the upper surface of the optical fiber.

[0041] In some embodiments, the chiral mechanical superstructure includes 2 to 6 chiral helical cantilever beams. The number of chiral helical cantilever beams or the thickness of the beams themselves can be varied by tunable parameter design, causing the system stiffness to change linearly with the number or thickness, which can greatly improve the range customization capability of the fiber optic accelerometer. In this embodiment, the thickness of each chiral helical cantilever beam can be from 1 μm to 10 μm. For example... Figure 6 The figure shows the load-displacement stiffness control curves of the fiber optic accelerometer under different numbers of chiral helical cantilever beams in this embodiment. In the left figure, 2, 3, 4, and 5 represent the number of chiral helical cantilever beams, respectively. In this embodiment, each chiral helical cantilever beam is a ring-shaped strip structure, and the chiral helical cantilever beams are arranged concentrically nested.

[0042] This invention also provides a preferred embodiment of the above-mentioned fiber optic accelerometer fabrication method, in which the chiral mechanical superstructure is realized and fixed on top of the fiber cladding through digital light processing, nanoimprinting, or multilayer photolithography combined with deep silicon etching or electron beam etching. Specifically, digital light processing is a rapid prototyping technology that uses a projector to solidify photosensitive polymer liquid layer by layer to create 3D printed objects. Digital light processing is a light modulation technology based on microelectromechanical systems (MEMS). It operates through an optical semiconductor chip of a digital micromirror device (DMD). In this embodiment, the input preset chiral mechanical superstructure image or graphic signal is directly converted into digital code to control the light and complete precise mapping. The DMD chip is the physical basis of digital light processing (DLP) technology and consists of millions of tiny mirrors. A DMD integrates an array of micromirrors on a CMOS semiconductor substrate. Each micromirror corresponds to a pixel in the final image. These micromirrors are extremely small, with a side length of only about 14 micrometers. The DMD chip has a micromirror spacing as small as 5.4 micrometers, and the array can accommodate more than 8.9 million micromirrors. Each micromirror is supported by a hinge structure below and can be independently deflected rapidly and precisely along its diagonal under electrostatic force. The micromirrors have two stable states: "on" and "off," with deflection angles ranging from ±10° to ±17°. In the "on" state, the micromirror reflects incident light into the projection lens, forming a bright pixel on the screen. In the "off" state, the micromirror reflects light elsewhere (such as being absorbed by a light absorber), forming a dark pixel. Pulse width modulation (PWM) technology controls the time ratio of each micromirror switching between the "on" and "off" states. The micromirrors can switch on and off thousands of times per second; a higher "on" time ratio results in brighter pixels, thus producing various shades of gray from black to white. In this embodiment, photosensitive resin is used to generate the chiral mechanical superstructure, and digital light processing (DLP) technology can project and cure an entire layer at once, thus far exceeding the speed of point-by-point scanning stereolithography. Meanwhile, Digital Light Processing (DLP) technology is a maskless lithography technique that directly programs and controls light through a DMD chip to "print" circuit patterns on a substrate. DLP eliminates the need for physical photomasks; designs can be updated simply by modifying graphic files in the software, significantly shortening development cycles and reducing costs. Furthermore, current DLP systems can achieve sub-micron level image resolution and offer fast exposure speeds, making them suitable for mass production. Their high contrast ratio (up to 10000:1 or higher) ensures sharp edge definition. Moreover, DLP technology can adapt to complex surfaces: during the generation of chiral mechanical superstructures, when the substrate is uneven, the DLP system can adjust the projected image in real time to match the actual surface morphology, ensuring accurate pattern printing.

[0043] Nanoimprinting is a micro / nano pattern replication technology based on mechanical deformation. Unlike traditional optical lithography, which utilizes photochemical modification (exposure altering the solubility of the photoresist), the core physical mechanism of nanoimprinting utilizes the topological structure of a template / stamp to physically extrude and cause the resist to undergo viscous deformation, followed by curing (thermal curing or UV curing) to lock the pattern. In this embodiment, thermal nanoimprinting can be used: a thermoplastic polymer is used as the resist. The process temperature needs to be raised above the polymer's glass transition temperature to make it viscous before pressure is applied, followed by cooling and demolding. Alternatively, UV nanoimprinting can be used, employing a UV-curable liquid monomer (acrylate-based) as the resist. Imprinting is performed at room temperature, while UV exposure through a quartz template causes cross-linking and curing.

[0044] The multilayer photolithography combined with deep silicon etching process utilizes multilayer photolithography to define complex patterns, and then anisotropic dry etching is used to vertically transfer the planar patterns to the silicon substrate with an extremely high aspect ratio, completing the 3D structure formation. In 3D forming, not just a single mask is used; instead, photoresist is applied again and photolithography is repeated on the surface where deep trenches have been etched, forming a new pattern on the upper layer. After the photoresist pattern is transferred to the silicon surface as a mask, deep reactive ion etching (DRIE) is used; in this embodiment, the Bosch process is selected for processing. The electron beam lithography described in this embodiment is a technique for processing chiral mechanical superstructures on a substrate coated with an electron-sensitive material (such as PMMA photoresist or HSQ photoresist).

[0045] The preferred embodiment of the present invention describes the fabrication method of the fiber optic accelerometer, such as... Figure 3As shown, the process includes: applying photoresist to the window of an objective lens using two-photon polymerization technology and immersing the end face of an optical fiber in the photoresist; focusing a femtosecond laser through the objective lens onto the inside of the photoresist, using the end face of the optical fiber as the processing base surface to print a chiral mechanical superstructure; placing the chiral mechanical superstructure in a solvent for wet development; and after the photoresist dissolves, the intrinsic elastic restoring force of the chiral helical cantilever beam pulls up the central mass block, achieving suspension and self-release. The chiral mechanical superstructure includes: a support base, at least one support column disposed on the side of the upper end face of the support base, elastic connecting rods disposed at the upper ends of each support column, at least two chiral helical cantilever beams connected to the upper ends of the support columns via each elastic connecting rod, and a central mass block located above the support base and at the center of the area surrounded by each chiral helical cantilever beam; each chiral helical cantilever beam is centrally symmetrically distributed with respect to the central mass block; the outer end of each chiral helical cantilever beam is connected to each elastic connecting rod, and the other end of each chiral helical cantilever beam is connected to the central mass block; the central mass block is suspended and supported above the support base, and there is a predetermined vertical distance between the central mass block and the support base.

[0046] It should be noted that two-photon polymerization (TPP) is a photochemical chain reaction based on two-photon absorption that transforms liquid photosensitive resin into a solid polymer. A photosensitive molecule simultaneously absorbs two low-energy (long-wavelength) photons within an extremely short time of approximately one femtosecond; the sum of their energies is required to excite and initiate polymerization. TPP is a micro / nano additive manufacturing technology based on nonlinear optical effects. It utilizes a femtosecond laser to precisely focus within the material, initiating a polymerization reaction at the focal point through the two-photon absorption effect, thereby creating the three-dimensional micro / nano structure of the chiral mechanical superstructure in the embodiments of this invention.

[0047] In this embodiment, photoresist is applied to the glass window of the objective lens, and the tip of an optical fiber is immersed in the photoresist. A femtosecond laser is focused through the objective lens onto the interior of the photoresist, using the fiber tip as the processing surface to 3D print the chiral mechanical superstructure. The solvent used can be PGMEA, propylene glycol methyl ether acetate, a photoresist solvent. Wet development is the process of dissolving the exposed (or unexposed) portions of the photoresist using a developing solution.

[0048] The connection between the chiral helical beam and the elastic connecting rod directly generates a compression-torsion coupling effect, which is the root cause of the intrinsic QZS. Therefore, the chiral mechanical superstructure of this invention does not require any complex anti-spring components and can reduce the stiffness to 0.012 N / m.

[0049] Furthermore, a chiral mechanical superstructure was in situ integrated onto the top of an optical fiber to construct a Fabry-Perot interferometer: achieving a high signal-to-noise ratio and electromagnetic interference-free conversion of mechanical displacement (even at the sub-nanometer level) into optical intensity signals.

[0050] In this embodiment of the invention, an auxiliary development structure is integrally printed on the support base. During development, the auxiliary development structure prevents the central mass block from directly contacting the upper surface of the optical fiber due to the dissolution and shrinkage of the photoresist, thus preventing irreversible intermolecular adhesion. This embodiment of the invention addresses the problem of easy collapse during the development of ultra-soft structures by proposing a manufacturing process with an auxiliary development pad, utilizing the intrinsic elasticity of the structure to achieve non-destructive self-release after liquid-phase development. It introduces a 3D printing method for self-release of suspended microstructures without post-processing, combining the auxiliary development structure with the structure's own elastic stretching. The release process with the auxiliary development structure brings the technical effect of zero risk of post-processing damage. Traditional methods for removing temporary support pillars easily damage micro / nano structures and are difficult to operate. This invention utilizes the structure's own elasticity to achieve detachment, realizing high-yield manufacturing of large-span suspended ultra-flexible devices.

[0051] It is understandable that during wet development, one can choose not to use physical isolation pads (auxiliary development structures), but instead use an auxiliary layer that is subsequently sublimated by controlled heating or dissolved by a specific chemical solution. Alternatively, when the photoresist dissolves and shrinks, the central mass block can be prevented from directly contacting the upper end face of the optical fiber, thus preventing irreversible intermolecular adhesion.

[0052] This invention integrates a chiral mechanical superstructure in situ onto the tip of an optical fiber to construct a Fabry-Perot interferometer (FPI). In this fiber optic accelerometer, the Fabry-Perot microcavity-based interferometer detects minute changes in the distance between the fiber end face and the reflecting surface (lower surface of the central mass block) to deduce the acceleration applied to the fiber optic accelerometer. The manufacturing method of this fiber optic accelerometer is a supportless, one-step molding process with extremely high yield. By employing an auxiliary development isolation structure combined with the intrinsic elasticity of the structure, it completely solves the problem of surface tension adhesion and collapse during wet development of large-span, ultra-flexible micro / nano structures, achieving one-step in-situ manufacturing.

[0053] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A chiral mechanical superstructure, characterized in that, include: The support base, at least one support column disposed on the side of the upper end face of the support base, an elastic connecting rod disposed at the upper end of each of the support columns, at least two chiral helical cantilever beams connected to the upper end of the support columns through each of the elastic connecting rods, and a central mass block located above the support base and at the center of the area surrounded by each of the chiral helical cantilever beams. Each of the chiral helical cantilever beams has a helical shape with the same direction of rotation; each of the chiral helical cantilever beams is centrally symmetrically distributed relative to the central mass block; the outer end of each chiral helical cantilever beam is connected to each of the elastic connecting rods, and the other end of each chiral helical cantilever beam is connected to the central mass block; the central mass block is suspended and supported above the support base, and there is a preset vertical distance between the central mass block and the support base.

2. The chiral mechanical superstructure according to claim 1, characterized in that, Each of the chiral helical cantilever beams is a ring-shaped strip structure, and the chiral helical cantilever beams are arranged in a concentric nested manner.

3. The chiral mechanical superstructure according to claim 1, characterized in that, The chiral mechanical superstructure also includes an auxiliary developing structure, which consists of several pads of the same size, evenly distributed on the support base.

4. A fiber optic accelerometer, characterized in that, include: The chiral mechanical superstructure and optical fiber as described in claim 1; The support base is fixed to the top of the optical fiber. The support base is hollow. The central mass block is suspended and supported above the optical fiber. The lower surface of the central mass block and the end face of the optical fiber form a Fabry-Perot interference microcavity.

5. The fiber optic accelerometer according to claim 4, characterized in that, The optical fiber is a single-mode optical fiber.

6. The fiber optic accelerometer according to claim 4, characterized in that, The chiral mechanical superstructure is printed on top of the fiber cladding of the optical fiber via additive manufacturing.

7. A method for manufacturing the fiber optic accelerometer according to any one of claims 4-6, characterized in that, The chiral mechanical superstructure is realized by digital light processing, nanoimprinting, or multilayer photolithography combined with deep silicon etching or electron beam etching and fixed on the top section of the optical fiber.

8. A method for manufacturing an optical fiber accelerometer according to any one of claims 4-6, characterized in that, include: Drop photoresist onto the window of the objective lens and immerse the end face of the optical fiber in the photoresist; Using two-photon polymerization technology, a femtosecond laser is focused inside the photoresist through an objective lens, and the photoresist is scanned and cured using the fiber end face as the processing base surface to form a chiral mechanical superstructure. Chiral mechanical superstructures were placed in a solvent for wet development. After the photoresist dissolves, the central mass block is lifted by the intrinsic elastic restoring force of the chiral helical cantilever beam, detaches from the support base, and thus achieves self-release from the air.

9. The preparation method according to claim 8, characterized in that, The solvent is propylene glycol methyl ether acetate.

10. The preparation method according to claim 8, characterized in that, It also includes the integrated printing of an auxiliary developing structure on the support base.

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