Mode coupling-based micro-opto-electro-mechanical accelerometer and acceleration measurement method

Abstract

The invention provides a mode coupling-based micro-opto-electro-mechanical accelerometer and an acceleration measurement method. The accelerometer comprises a sensing layer, and the sensing layer comprises a supporting outer frame, a plurality of snake-shaped beams, a detection mass block, two groups of optical sensing structures, an optical fiber transmission unit and a calculation module; the detection mass block is elastically connected with the first frame and the second frame of the supporting outer frame through a plurality of S-shaped beams. The input gratings, the fixed waveguides and the output gratings in the two groups of optical sensing structures are symmetrically arranged on the first frame and the second frame respectively; the movable waveguides are symmetrically arranged on two sides of the detection mass block and are in one-to-one correspondence with the two fixed waveguides; and the resolving module is used for resolving according to the optical power of the two input optical fibers and the optical power of the two output optical fibers to obtain the value of the acceleration input from the outside. According to the technical scheme, the technical problems that in the prior art, the structure is complex, and the equipment machining requirement is high are solved.

Description

Technical Field

[0001] This invention relates to the field of optical accelerometer technology, and more particularly to a micro-opto-electro-mechanical accelerometer based on mode coupling and an acceleration measurement method. Background Technology

[0002] With the development of micro-nano fabrication technology, traditional microelectromechanical (MEMS) accelerometers have been widely used in aerospace, medical, and automotive fields due to their miniaturization and integration advantages. However, MEMS accelerometers, which use electrical principles to sense the displacement of a mass under acceleration, suffer from poor electromagnetic interference resistance and low signal-to-noise ratio. Opto-electromechanical (OEEM) accelerometers combine micro-optical elements (micro-waveguides, micro-resonant cavities, micro-gratings, photonic crystals, etc.) with MEMS systems, achieving high-sensitivity acceleration sensing based on principles such as intensity modulation, phase modulation, and wavelength modulation. They also offer advantages such as electromagnetic interference resistance, low cost, and suitability for mass production. Currently, high-resolution OEEM accelerometers both domestically and internationally mainly employ structures such as micro-ring resonant cavities and photonic crystals, but these require sophisticated equipment fabrication and are still in the laboratory pre-research stage. Summary of the Invention

[0003] This invention provides a micro-opto-electro-mechanical accelerometer and acceleration measurement method based on mode coupling, which can solve the technical problems of complex structure and high equipment processing requirements in the prior art.

[0004] According to one aspect of the present invention, a mode-coupled micro-opto-electro-mechanical accelerometer is provided, the accelerometer including a sensing layer, the sensing layer comprising:

[0005] The supporting outer frame has a first border and a second border that are parallel to each other.

[0006] Multiple serpentine beams are located within the supporting outer frame and are symmetrically arranged on the first and second side frames;

[0007] The detection mass block is set inside the supporting outer frame and is elastically connected to the first and second side frames through multiple serpentine beams. The detection mass block is used to translate along the direction of the lowest stiffness of the serpentine beams when an external acceleration is input.

[0008] Two sets of optical sensing structures are provided. Each set includes an input grating, a fixed waveguide, an output grating, and a moving waveguide. The fixed waveguide has a first straight segment and S-curved segments on both sides. The input grating and the output grating are connected to the two S-curved segments of the fixed waveguide, respectively. The moving waveguide has a second straight segment and arc-shaped segments on both sides. The input grating, fixed waveguide, and output grating in the two sets of optical sensing structures are symmetrically arranged on the first and second frame edges, respectively. The moving waveguides in the two sets of optical sensing structures are symmetrically arranged on both sides of the detection mass block and correspond one-to-one with the two fixed waveguides. The first and second straight segments in each set of optical sensing structures are parallel to each other, and their spacing changes with the translation of the detection mass block. The spacing change is converted into an optical power change through the mode coupling effect of the first and second straight segments.

[0009] The optical fiber transmission unit includes two input optical fibers and two output optical fibers. The two input optical fibers are respectively connected to two input gratings and are used to input light into the fixed waveguide through the input gratings. The two output optical fibers are respectively connected to two output gratings and are used to receive light output from the fixed waveguide through the output gratings.

[0010] The calculation module is used to calculate the value of the external input acceleration based on the optical power of the two input fibers and the optical power of the two output fibers.

[0011] Furthermore, the ratio of the length of the second straight segment to the length of the first straight segment is greater than or equal to one-tenth and less than or equal to one-fifth.

[0012] Furthermore, in the absence of acceleration input, the spacing between the first and second straight segments in each optical sensing structure results in a light coupling efficiency of half.

[0013] Furthermore, the accelerometer also includes an upper support layer, which includes an upper support plate and a first boss disposed on the upper support plate. The upper support plate covers the outer support frame through the first boss so that the upper support plate and the upper surface of the outer support frame maintain a first preset distance. The upper support plate is provided with multiple through holes for inserting input optical fibers and / or output optical fibers.

[0014] Furthermore, the accelerometer also includes a lower support layer, which includes a lower support plate and a second protrusion disposed on the lower support plate. The lower support plate covers the outer support frame through the second protrusion so that a second preset distance is maintained between the lower support plate and the lower surface of the outer support frame.

[0015] Furthermore, the via is an inclined via.

[0016] Furthermore, both the input and output optical fibers are single-mode optical fibers.

[0017] According to another aspect of the present invention, an acceleration measurement method using the accelerometer proposed above is provided, the method comprising:

[0018] Light is simultaneously input into two fixed waveguides in two sets of optical sensing structures via two input optical fibers;

[0019] When an external acceleration is applied, the optical power of the two input optical fibers and the two output optical fibers is measured respectively.

[0020] The value of the external input acceleration is calculated based on the optical power of the two input fibers and the optical power of the two output fibers.

[0021] Furthermore, the value of the external input acceleration is calculated using the following formula based on the optical power of the two input fibers and the optical power of the two output fibers:

[0022] a = k(R1 - R2),

[0023] R1 = P 1out / P 1in ,

[0024] R2 = P 2out / P 2in ,

[0025] In the above formula, a represents the value of the external input acceleration, k represents the scaling factor, R1 represents the relative intensity of the optical power of the input fiber and the output fiber in the first set of optical sensing structures, and P 1in P represents the optical power input to the optical fiber in the first set of optical sensing structures. 1out R2 represents the optical power of the output fiber in the first optical sensing structure, and R2 represents the relative intensity of the optical power of the input and output fibers in the second optical sensing structure. 2in P represents the optical power of the input fiber in the second set of optical sensing structures. 2out This indicates the optical power of the output fiber in the second set of optical sensing structures.

[0026] This invention provides a mode-coupled micro-opto-electro-mechanical accelerometer and acceleration measurement method. The accelerometer elastically connects a detection mass block to a supporting outer frame using a serpentine beam, converting external acceleration into displacement of the detection mass block along the direction of lowest stiffness of the serpentine beam. By setting an input grating, a fixed waveguide, and an output grating on two opposite sides of the supporting outer frame, and a moving waveguide on the detection mass block, the mode coupling effect of the straight sections of the fixed and moving waveguides is utilized. Light is transmitted to the fixed waveguide via the input fiber and the input grating, and the light output from the fixed waveguide is extracted via the output fiber and the output grating. This converts the displacement of the detection mass block into a change in the spacing between the straight sections of the two waveguides, and further into a change in the optical power of the two input and two output fibers. The external acceleration can be calculated from the optical power attenuated by mode coupling. Since the coupling efficiency between the two waveguides is highly sensitive to the lateral spacing, the accelerometer has high resolution and is simple in structure and easy to manufacture. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] Figure 1 A schematic diagram of the overall structure of a mode-coupled micro-opto-electro-mechanical accelerometer according to a specific embodiment of the present invention is shown;

[0029] Figure 2 A schematic diagram of the structure of the sensing layer provided according to a specific embodiment of the present invention is shown;

[0030] Figure 3 It shows Figure 2 A schematic diagram of the optical sensing structure in the diagram;

[0031] Figure 4 A side view of the upper support layer provided according to a specific embodiment of the present invention is shown;

[0032] Figure 5 A top view of the upper support layer provided according to a specific embodiment of the present invention is shown.

[0033] The above figures include the following reference numerals:

[0034] 10. Upper support layer; 11. First boss; 12. Via; 20. Sensing layer; 21. Supporting outer frame; 211. First border; 212. Second border; 22. Serpentine beam; 23. Detection mass block; 24. Optical sensing structure; 241. Input grating; 242. Fixed waveguide; 243. Output grating; 244. Moving waveguide; 30. Lower support layer; 40. Fiber optic transmission unit; 41. Input fiber optic cable; 42. Output fiber optic cable. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0038] like Figure 1 As shown, a specific embodiment of the present invention provides a mode-coupled micro-opto-electro-mechanical accelerometer, the accelerometer including a sensing layer 20, the sensing layer 20 including:

[0039] The supporting outer frame 21 has a first border 211 and a second border 212 that are parallel to each other;

[0040] Multiple serpentine beams 22 are located within the supporting outer frame 21 and are symmetrically arranged on the first side frame 211 and the second side frame 212;

[0041] The detection mass block 23 is set inside the supporting outer frame 21 and is elastically connected to the first frame 211 and the second frame 212 through multiple serpentine beams 22. The detection mass block 23 is used to translate along the direction of the lowest stiffness of the serpentine beams 22 when an external acceleration is input.

[0042] Two sets of optical sensing structures 24, each including an input grating 241, a fixed waveguide 242, an output grating 243, and a moving waveguide 244. The fixed waveguide 242 has a first straight section and S-curved sections on both sides thereof. The input grating 241 and the output grating 243 are respectively connected to the two S-curved sections of the fixed waveguide 242. The moving waveguide 244 has a second straight section and arc-shaped sections on both sides thereof. The input grating 241 and the fixed waveguide 242 in the two sets of optical sensing structures 24 are... 2 and output grating 243 are symmetrically arranged on the first frame 211 and the second frame 212, respectively. The moving waveguides 244 in the two sets of optical sensing structures 24 are symmetrically arranged on both sides of the detection mass block 23 and correspond one-to-one with the two fixed waveguides 242. The first straight segment and the second straight segment in each set of optical sensing structures 24 are parallel to each other and their spacing changes with the translation of the detection mass block 23. The spacing change is converted into optical power change through the mode coupling effect of the first straight segment and the second straight segment.

[0043] The optical fiber transmission unit 40 includes two input optical fibers 41 and two output optical fibers 42. The two input optical fibers 41 are respectively connected to two input gratings 241 and are used to input light into the fixed waveguide 242 through the input gratings 241. The two output optical fibers 42 are respectively connected to two output gratings 243 and are used to receive light output from the fixed waveguide 242 through the output gratings 243.

[0044] The calculation module is used to calculate the value of the external input acceleration based on the optical power of the two input optical fibers 41 and the optical power of the two output optical fibers 42.

[0045] This configuration provides a mode-coupled micro-opto-electro-mechanical accelerometer. By elastically connecting the detection mass to a supporting outer frame using a serpentine beam, the external output acceleration is converted into displacement of the detection mass along the direction of lowest stiffness of the serpentine beam. By setting input gratings, fixed waveguides, and output gratings on two opposite sides of the supporting outer frame, and a moving waveguide on the detection mass, the mode coupling effect of the straight sections of the fixed and moving waveguides is utilized. Light is transmitted to the fixed waveguide through the input grating via an input fiber, and the light output from the fixed waveguide is extracted through the output grating via an output fiber. This converts the displacement of the detection mass into a change in the spacing between the straight sections of the two waveguides, and further into a change in the optical power of the two input and two output fibers. The external acceleration can be calculated from the optical power attenuated by mode coupling. Since the coupling efficiency between the two waveguides is highly sensitive to the lateral spacing, the accelerometer has high resolution. Furthermore, it has a simple structure and is easy to manufacture. Compared with existing technologies, the technical solution of this invention can solve the technical problems of complex structures and high equipment processing requirements in existing technologies.

[0046] As a specific embodiment of the present invention, please refer to Figure 2 The detection mass block 23 is located in the center of the sensing layer 20 and is connected to the supporting outer frame 21 via four serpentine beams 22 distributed at the four corners. The centers of the detection mass block 23 and the supporting outer frame 21 are aligned. The serpentine beams 22 are located on opposite sides of the detection mass block 23 and point in the same direction. This direction has the lowest stiffness of the serpentine beam and is called the acceleration sensitive axis. Figure 2 The arrows indicate the direction. Two identical optical sensing structures 24 are symmetrically distributed on the sensing layer 20, on the same side as the serpentine beam 22. The input grating 241, fixed waveguide 242, and output grating 243 are located on the supporting outer frame 21, while the moving waveguide 244 is located on the detection mass block 23 and moves with the detection mass block 23. The fixed waveguide 242 has S-curved sections at both ends and a straight section in the middle. The input grating 241 and output grating 243 are connected to the S-curved sections of the fixed waveguide 242, respectively. The moving waveguide 244 has a straight section and arc bends on both sides of the straight section. The straight sections of the fixed waveguide 242 and the moving waveguide 244 are located at the edges of the supporting outer frame 21 and the detection mass block 23, respectively, and are parallel to each other. The distance between them ensures that light couples from the fixed waveguide 242 into the moving waveguide 244. When an external acceleration is applied, the detection mass block 23 undergoes a micro-displacement along the direction of lowest stiffness (acceleration-sensitive axis) of the serpentine beam 22. This micro-displacement is detected by two optical sensing structures 24 on the same side as the serpentine beam 22 and converted into optical power information. The direction of lowest stiffness of the serpentine beam 22 can be referenced to the axial compression and tension direction of a spring. The curved sections on both sides of the second straight section on the moving waveguide 244 can also adopt other shapes, such as straight sections, as long as their ends point away from the straight section of the fixed waveguide 242.

[0047] In the above embodiments, the serpentine beam, as an elastic beam structure, has the lowest stiffness in the detection direction, but it is also prone to deformation in the direction perpendicular to the detection direction, meaning it has high cross-axis sensitivity. However, based on the mode coupling relationship between the moving waveguide and the fixed waveguide mentioned above in this invention, the relative displacement of the two waveguides in the direction perpendicular to the acceleration sensing axis will not affect the efficiency of light coupling from the fixed waveguide to the moving waveguide, thus compensating for the shortcomings of the serpentine beam. Therefore, the optical sensing structure in this invention is very suitable for use in conjunction with the serpentine beam to form an accelerometer with high resolution and resistance to cross-axis interference.

[0048] Furthermore, in the optical sensing structure 24, the straight section of the moving waveguide 244 and the straight section of the fixed waveguide 242 form a coupling region, the length of which is the length of the straight section of the fixed waveguide 244. To improve the cross-sensitivity of the accelerometer, in this embodiment, the ratio of the length of the second straight section to the length of the first straight section is set to be greater than or equal to one-tenth and less than or equal to one-fifth. Preferably, the length of the straight section of the moving waveguide is one-tenth the length of the straight section of the fixed waveguide. With this configuration, the relative displacement between the moving waveguide 244 and the fixed waveguide 242 in the direction perpendicular to the acceleration sensing axis will not affect the efficiency of light coupling from the fixed waveguide into the moving waveguide, thereby further reducing the cross-sensitivity of the accelerometer and improving the acceleration measurement accuracy.

[0049] Based on the above embodiment, the light transmission process in the optical sensing structure 24 is as follows: the output light from the input fiber 41 is introduced into the fixed waveguide 242 through the input grating 241. When the light propagates to the coupling region formed by the fixed waveguide 242 and the moving waveguide 244, due to the mode coupling effect, the transmission mode fields of the two waveguides influence each other, and some light is coupled from the fixed waveguide 242 into the moving waveguide 244. Since the distance between the S-bend section of the fixed waveguide 242 and the arc-bend section of the moving waveguide 244 increases (relative to the distance between the two straight sections), the light coupled into the moving waveguide 244 will not return to the fixed waveguide 242. Therefore, the light in the fixed waveguide 242 is attenuated after passing through the coupling region, and then passes through the S-bend and the output grating 243 before entering the output fiber 42. When other structural parameters are determined, the degree of light attenuation in the coupling region is related to the distance between the two straight sections. Its working principle is as follows: the output light of the input fiber 41 is introduced into the moving waveguide 244 through the input grating 241. The light transmitted in the moving waveguide 244 is led out to the output fiber 42 through the output grating 243. When the light is transmitted to the coupling region, due to the mode coupling effect, the transmission mode fields of the two waveguides affect each other. Some light is coupled from the fixed waveguide 242 into the moving waveguide 244, which causes the output light intensity or optical power of the output fiber 42 to be attenuated. The smaller the distance between the moving waveguide 244 and the fixed waveguide 242, the higher the coupling efficiency, and thus the lower the output light intensity or optical power of the fixed waveguide 242.

[0050] Furthermore, in this embodiment of the invention, in the initial state, that is, when there is no acceleration input, the spacing between the first and second straight segments in each set of optical sensing structures 24 is reasonably set so that the optical coupling efficiency between them is half. This configuration enables the accelerometer to have optimal acceleration sensitivity and range. When there is an external acceleration input along the acceleration-sensitive axis, the detection mass block 23 will shift to one side, causing the spacing between the coupling regions of the moving waveguide 244 and the fixed waveguide 242 in the two optical sensing structures 24 to change; that is, the spacing on one side increases, and the spacing on the other side decreases. The intensity or power of the light output by the two optical sensing structures 24 through the output fiber 42 decreases linearly with acceleration, and increases linearly with acceleration. Based on this, the acceleration can be calculated from the differential light intensity or differential light power information of the two optical sensing structures 24.

[0051] In addition, please refer to Figure 1 The accelerometer provided in this embodiment of the invention further includes an upper support layer 10 and a lower support layer 30. The upper support layer 10 includes an upper support plate and a first protrusion 11 disposed on the upper support plate. The upper support plate covers the outer support frame 21 through the first protrusion 11 to maintain a first preset distance between the upper support plate and the upper surface of the outer support frame 21. The upper support plate has multiple through holes 12 for passing through an input optical fiber 41 and / or an output optical fiber 42. The lower support layer 30 includes a lower support plate and a second protrusion disposed on the lower support plate. The lower support plate covers the outer support frame 21 through the second protrusion to maintain a second preset distance between the lower support plate and the lower surface of the outer support frame 21. The specific values ​​of the first preset distance and the second preset distance are determined by comprehensively considering the thickness of the mass block and the thickness of the optical sensing structure. The distance is adjusted by adjusting the height of the first protrusion 11 and the second protrusion.

[0052] Please refer to this again. Figure 4 and Figure 5 In a specific embodiment of the present invention, the upper support layer 10, the sensing layer 20, and the lower support layer 30 all have rectangular frames with the same length and width. The upper support layer 10 has identical protrusions at its four corners. The upper support layer 10 is mounted on the side of the sensing layer 20 with the optical sensing structure 24, and the protrusion surfaces contact the supporting outer frame 21 of the sensing layer 20, thereby providing space for the movement of the detection mass block 23 and the optical sensing structure 24. The lower support layer 30 also has identical protrusions at its four corners and is mounted on the other side of the sensing layer 20. The protrusion surfaces contact the supporting outer frame 21 of the sensing layer 20, thereby providing space for the movement of the detection mass block 23. In other words, the upper support layer 10 and the lower support layer 30 are connected to the upper and lower surfaces of the sensing layer 20, respectively, providing protection for the sensing layer 20. Furthermore, as... Figure 4As shown, via 12 is an angled via, with two input optical fibers 41 and two output optical fibers 42 installed in each of the four angled vias. Both input optical fibers 41 and output optical fibers 42 are single-mode optical fibers, and the input light source is a laser source. The lower end face of via 12 is aligned with the center of input grating 241 and output grating 243 on sensing layer 20, respectively. The angle between input optical fiber 41 and input grating 241, and the angle between output optical fiber 42 and output grating 243 are the same. By adjusting the angle of via 12, the light input and output loss can be minimized.

[0053] According to another aspect of the present invention, an acceleration measurement method using the accelerometer proposed above is provided, the method comprising:

[0054] Light is simultaneously input into two fixed waveguides in two sets of optical sensing structures via two input optical fibers;

[0055] When an external acceleration is applied, the optical power of the two input optical fibers and the two output optical fibers is measured respectively.

[0056] The value of the external input acceleration is calculated based on the optical power of the two input fibers and the optical power of the two output fibers.

[0057] Furthermore, the optical power P of the two input optical fibers is obtained respectively. 1in and P 2in The corresponding output optical power of the output fiber is P. 1out and P 2out The relative intensity of the two optical sensing structures is calculated, i.e., R1 = P. 1out / P 1in and R2=P 2out / P 2in Theoretically, based on the aforementioned working principle, when there is no external acceleration along the sensitive axis, R1 = R2 = 0.5; when there is external acceleration along the sensitive axis, the acceleration a = k(R1 - R2) can be calculated.

[0058] In other words, in this embodiment of the invention, the value of the externally input acceleration is calculated using the following formula based on the optical power of the two input fibers and the optical power of the two output fibers:

[0059] a = k(R1 - R2),

[0060] R1 = P 1out / P 1in ,

[0061] R2 = P 2out / P 2in ,

[0062] In the above formula, a represents the value of the external input acceleration, k represents the scaling factor, which is calibrated through a gravitational field tumbling experiment, R1 represents the relative intensity of the optical power of the input fiber and the output fiber in the first set of optical sensing structures, and P 1in P represents the optical power input to the optical fiber in the first set of optical sensing structures. 1out R2 represents the optical power of the output fiber in the first optical sensing structure, and R2 represents the relative intensity of the optical power of the input and output fibers in the second optical sensing structure. 2in P represents the optical power of the input fiber in the second set of optical sensing structures. 2out This indicates the optical power of the output fiber in the second set of optical sensing structures.

[0063] In this way, an acceleration measurement method is provided. Since the micro-opto-electro-mechanical accelerometer based on mode coupling proposed in the present invention has high resolution, the acceleration value measured by the accelerometer has high accuracy.

[0064] In summary, this invention provides a micro-opto-electro-mechanical accelerometer and acceleration measurement method based on mode coupling. This accelerometer, by elastically connecting a detection mass block to a supporting outer frame using a serpentine beam, can convert external output acceleration into displacement of the detection mass block along the direction of lowest stiffness of the serpentine beam. By setting an input grating, a fixed waveguide, and an output grating on two opposite sides of the supporting outer frame, and a moving waveguide on the detection mass block, the mode coupling effect of the straight sections of the fixed and moving waveguides is utilized. Light is transmitted to the fixed waveguide via the input fiber and the input grating, and the light output from the fixed waveguide is extracted via the output fiber and the output grating. This converts the displacement of the detection mass block into a change in the spacing between the straight sections of the two waveguides, and further into a change in the optical power of the two input and two output fibers. The external acceleration can be calculated from the optical power attenuated by mode coupling. Since the coupling efficiency between the two waveguides is highly sensitive to the lateral spacing, the accelerometer has high resolution, and its structure is simple and easy to manufacture. Compared with the prior art, the technical solution of the present invention can solve the technical problems of complex structure and high equipment processing requirements in the prior art.

[0065] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0066] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A micro-opto-electro-mechanical accelerometer based on mode coupling, characterized in that, The accelerometer includes a sensing layer (20), the sensing layer (20) comprising: A supporting outer frame (21) has a first border (211) and a second border (212) that are parallel to each other; Multiple serpentine beams (22) are located within the supporting outer frame (21) and symmetrically arranged on the first side frame (211) and the second side frame (212); The detection mass block (23) is disposed within the supporting outer frame (21) and is elastically connected to the first side frame (211) and the second side frame (212) through multiple serpentine beams (22). The detection mass block (23) is used to translate along the direction of the lowest stiffness of the serpentine beams (22) when an external acceleration is input. Two sets of optical sensing structures (24), each set of optical sensing structures (24) includes an input grating (241), a fixed waveguide (242), an output grating (243), and a moving waveguide (244). The fixed waveguide (242) has a first straight section and S-curved sections on both sides thereof. The input grating (241) and the output grating (243) are respectively connected to the two S-curved sections of the fixed waveguide (242). The moving waveguide (244) has a second straight section and curved sections on both sides thereof. The input grating (241), the fixed waveguide (242), the output grating (243), and the moving waveguide (244) in the two sets of optical sensing structures (24) are connected to the two S-curved sections of the fixed waveguide (242). 42) and output grating (243) are symmetrically arranged on the first frame (211) and the second frame (212) respectively. The moving waveguide (244) in the two sets of optical sensing structures (24) are symmetrically arranged on both sides of the detection mass block (23) and correspond one-to-one with the two fixed waveguides (242). The first straight segment and the second straight segment in each set of optical sensing structures (24) are parallel to each other and their spacing changes with the translation of the detection mass block (23). The spacing change is converted into optical power change through the mode coupling effect of the first straight segment and the second straight segment. The optical fiber transmission unit (40) includes two input optical fibers (41) and two output optical fibers (42). The two input optical fibers (41) are respectively connected to two input gratings (241) for inputting light into the fixed waveguide (242) through the input gratings (241). The two output optical fibers (42) are respectively connected to two output gratings (243) for receiving light output from the fixed waveguide (242) through the output gratings (243). The calculation module is used to calculate the value of the externally input acceleration based on the optical power of the two input optical fibers (41) and the optical power of the two output optical fibers (42).

2. The accelerometer according to claim 1, characterized in that, The ratio of the length of the second straight segment to the length of the first straight segment is greater than or equal to one-tenth and less than or equal to one-fifth.

3. The accelerometer according to claim 1, characterized in that, When there is no acceleration input, the spacing between the first and second straight segments in each set of optical sensing structures (24) results in an optical coupling efficiency of half.

4. The accelerometer according to claim 1, characterized in that, The accelerometer also includes an upper support layer (10), which includes an upper support plate and a first boss (11) disposed on the upper support plate. The upper support plate covers the outer support frame (21) through the first boss (11) so that the upper support plate and the upper surface of the outer support frame (21) maintain a first preset distance. The upper support plate is provided with a plurality of through holes (12), which are used to pass through the input optical fiber (41) and / or the output optical fiber (42).

5. The accelerometer according to claim 4, characterized in that, The accelerometer also includes a lower support layer (30), which includes a lower support plate and a second protrusion disposed on the lower support plate. The lower support plate covers the outer support frame (21) through the second protrusion so that the lower support plate and the lower surface of the outer support frame (21) maintain a second preset distance.

6. The accelerometer according to claim 4, characterized in that, The via (12) is an inclined via.

7. The accelerometer according to any one of claims 1 to 6, characterized in that, Both the input fiber (41) and the output fiber (42) are single-mode fibers.

8. An acceleration measurement method using an accelerometer according to any one of claims 1 to 7, characterized in that, The method includes: Light is simultaneously input into two fixed waveguides in two sets of optical sensing structures via two input optical fibers; When an external acceleration is applied, the optical power of the two input optical fibers and the two output optical fibers is measured respectively. The value of the externally input acceleration is calculated based on the optical power of the two input fibers and the optical power of the two output fibers.

9. The acceleration measurement method according to claim 8, characterized in that, The value of the externally input acceleration is calculated using the following formula based on the optical power of the two input fibers and the optical power of the two output fibers: a = k(R1 - R2), R1=P 1out / P 1in , R2=P 2out / P 2in , In the above formula, a represents the value of the external input acceleration, k represents the scaling factor, R1 represents the relative intensity of the optical power of the input fiber and the output fiber in the first set of optical sensing structures, and P 1in P represents the optical power input to the optical fiber in the first set of optical sensing structures. 1out R2 represents the optical power of the output fiber in the first optical sensing structure, and R2 represents the relative intensity of the optical power of the input and output fibers in the second optical sensing structure. 2in P represents the optical power of the input fiber in the second set of optical sensing structures. 2out This indicates the optical power of the output fiber in the second set of optical sensing structures.

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