Optical acceleration sensor and acceleration sensor system

Abstract

The present invention provides an optical acceleration sensor and an acceleration sensor system, wherein the optical acceleration sensor comprises: a conductive optical fiber, which conducts light waves inside; a semiconductor structure, on which a Bragg grating is etched and aligned with the conductive optical fiber, modulating the incident light waves and reflecting them back to the conductive optical fiber; and a vibration component, which is connected to the semiconductor structure, senses the vibration of the object to be measured and transmits it to the Bragg grating. In this way, the semiconductor structure and the conductive optical fiber are separated and arranged, and when packaging is required, the semiconductor structure is directly packaged, which solves the problem that the bending radius of the optical fiber is too small and the packaged sensor size is too large; in addition, the semiconductor structure is more stable, so the problem that the Bragg fiber grating is brittle and easy to break and cannot measure high-frequency vibration signals is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical sensors, and in particular to an optical acceleration sensor and an acceleration sensor system. Background Art

[0002] The existing mainstream optical acceleration sensor technologies include Bragg fiber grating technology and Fabry-Perot optical resonant cavity technology. The former mainly modulates the core periodic refractive index of the fiber on ordinary optical fiber. This method easily makes the optical fiber brittle, and there are defects such as fatigue or even breakage of the optical fiber under long-term vibration, and it cannot measure high-frequency vibration signals. In addition, when encapsulated into a sensor, the bending radius of the optical fiber must be estimated to avoid attenuation of the optical signal, which results in the size of the packaged sensor not being very small, so it is not suitable for environments with strict internal space dimensions. The change of the optical signal of the latter is basically nonlinear, so for the sensor, the demodulated vibration signal is relatively distorted; and it is difficult to accurately control the cavity length of the resonant cavity in its manufacturing process, which sometimes makes it difficult for the required design wavelength to fall within the passband of the detection light, resulting in no signal output or garbled signals. Summary of the invention

[0003] The problem solved by the present invention is that the fiber Bragg grating optical fiber becomes brittle and cannot measure high-frequency vibration signals.

[0004] In order to solve the above problems, the present invention first provides an optical acceleration sensor, comprising:

[0005] Transmission optical fiber, which conducts light waves inside;

[0006] A semiconductor structure, on which a Bragg grating is etched and aligned with the transmission optical fiber, modulates the incident light wave and reflects it back to the transmission optical fiber;

[0007] The vibration component is connected to the semiconductor structure, senses the vibration of the object to be measured and transmits it to the Bragg grating.

[0008] In this way, by etching a Bragg grating on the semiconductor structure, the semiconductor structure and the conducting optical fiber are separated and set. In this way, when packaging is needed, the semiconductor structure can be directly packaged, and there is no need to consider the problem of the bending radius of the optical fiber, thereby solving the problem that the bending radius of the optical fiber is too small and the packaged sensor size is too large; in addition, the semiconductor structure is more stable, thus solving the problem that the optical fiber Bragg grating is brittle and easy to break, and cannot measure high-frequency vibration signals.

[0009] Optionally, the Bragg grating is etched on the semiconductor structure.

[0010] In this way, the Bragg grating is etched on the semiconductor structure, thereby increasing the robustness and portability of the Bragg grating arrangement.

[0011] Optionally, the center of mass of the vibration component coincides with the center of the semiconductor structure.

[0012] In this way, when the vibration component vibrates, the vibration direction is parallel to the length direction of the semiconductor structure, so that the Bragg grating is deformed only along the length direction without generating polarization.

[0013] Optionally, the vibration component includes a mass block and a cantilever arm, and the mass block is connected to the semiconductor structure through the cantilever arm.

[0014] In this way, the cantilever arm constrains the vibration direction of the mass block. When the object being measured vibrates, the mass block vibrates in the vibration direction, causing the cantilever beam to bend and swing, thereby leading to micro-deformation in the length direction of the Bragg grating.

[0015] Optionally, there are multiple mass blocks, and the masses of the mass blocks are the same.

[0016] In this way, uneven mass distribution of the entire vibration component caused by different masses of the mass blocks can be avoided, thereby limiting the vibration direction of the mass blocks and avoiding product polarization.

[0017] Optionally, the cantilever arms are of equal length and are radially and uniformly arranged around the semiconductor structure.

[0018] This arrangement can make the mass of the entire vibration assembly evenly distributed, thereby limiting the vibration direction of the mass block and avoiding product polarization.

[0019] Optionally, the number of the mass blocks is four.

[0020] Thus, the cross-shaped structure facilitates the processing and assembly of the semiconductor structure.

[0021] Optionally, a convex lens is provided on one end of the transmission optical fiber aligned with the Bragg grating.

[0022] In this way, the light waves propagating in the transmission optical fiber enter the Bragg grating in the form of parallel light through the convex lens; similarly, the light waves reflected by the Bragg grating are focused into the transmission optical fiber through the convex lens.

[0023] Optionally, it also includes a packaging shell, which wraps the semiconductor structure and the vibration component and is fixedly connected to the conductive optical fiber.

[0024] In this way, the semiconductor structure and the vibration component are packaged through packaging, thereby facilitating protection and reducing processing difficulty.

[0025] Next, an optical acceleration sensor system is provided, comprising the optical acceleration sensor mentioned above.

[0026] In this way, by etching a Bragg grating on the semiconductor structure, the semiconductor structure and the conducting optical fiber are separated and set. In this way, when packaging is needed, the semiconductor structure can be directly packaged, and there is no need to consider the problem of the bending radius of the optical fiber, thereby solving the problem that the bending radius of the optical fiber is too small and the packaged sensor size is too large; in addition, the semiconductor structure is more stable, thus solving the problem that the optical fiber Bragg grating is brittle and easy to break, and cannot measure high-frequency vibration signals.

[0027] Optionally, the optical acceleration sensor system further includes:

[0028] a light source generator that generates light waves for detection;

[0029] A signal demodulator, which demodulates the incident light wave into an electrical signal and calculates the corresponding acceleration;

[0030] An optical fiber coupler, one end of which is connected to the light source generator and the signal demodulator through optical fibers, and the other end of which is connected to the optical acceleration sensor through optical fibers, separates the light wave transmission channel of the optical acceleration sensor into the light wave transmission channel of the light source generator and the light wave transmission channel of the signal demodulator.

[0031] In this way, the acceleration of the object being measured can be accurately measured through the optical acceleration sensor system, and the material of the semiconductor structure is more stable, which is more convenient for measuring in high temperature, high pressure or high frequency vibration environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a structural diagram of an optical acceleration sensor according to an embodiment of the present invention;

[0033] Figure 2 is an interface diagram of an optical acceleration sensor according to an embodiment of the present invention;

[0034] Figure 3 is a packaging diagram of an optical acceleration sensor according to an embodiment of the present invention;

[0035] Figure 4 FIG. 4 is a schematic diagram of an optical acceleration sensor system according to an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1-optical acceleration sensor; 2-conduction optical fiber; 3-semiconductor structure; 31-Bragg grating; 4-vibration component; 41-mass block; 42-cantilever arm; 5-convex lens; 6-package shell; 7-light source generator; 8-signal demodulator; 9-fiber coupler. DETAILED DESCRIPTION

[0038] The existing mainstream optical acceleration sensor technologies include Bragg fiber grating technology and Fabry-Perot optical resonant cavity technology.

[0039] Fiber Bragg grating technology is to make Bragg gratings on ordinary optical fibers. There are generally two processes for this production, one is laser interference method, and the other is mask method. However, no matter which method is used, the coating layer needs to be stripped off. The optical fiber with the coating stripped off is brittle and easy to break. It is easy to fatigue or even break under long-term vibration. Therefore, not only is the service life too short, but it is also unable to measure high-frequency vibration signals.

[0040] In addition, when the bending radius of the optical fiber of the optical fiber sensor is too small, there is basically no signal output; therefore, when it is packaged into a sensor, the bending radius of the optical fiber must be at least 10 times the diameter of the optical fiber to avoid attenuation of the light signal. This results in the packaged sensor not being very small in size, and is therefore not suitable for environments with demanding internal space dimensions.

[0041] The Fabry-Perot optical resonant cavity technology utilizes the change in the cavity length of the resonant cavity to cause a corresponding change in the longitudinal mode spacing of the output comb structure, thereby causing a relative shift in the only wavelength within the passband light (which also serves as a filter) to detect dynamically changing optical signals.

[0042] However, the defects of Fabry-Perot optical resonant cavity technology are: first, the wavelength in the passband changes with the change of the longitudinal mode spacing, so the change of the optical signal is basically nonlinear. Therefore, for the sensor, the demodulated vibration signal is relatively distorted; second, it is difficult to accurately control the cavity length of the resonant cavity in its manufacturing process, which makes it difficult for the required design wavelength to fall within the passband of the detection light, resulting in no signal output or garbled signals.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] To solve at least one aspect of the above technical problems to a certain extent, Figure 1 As shown, it is a structural diagram of an optical acceleration sensor according to an embodiment of the present invention; wherein the optical acceleration sensor comprises:

[0045] A transmission optical fiber 2, in which light waves are transmitted;

[0046] A semiconductor structure 3, on which a Bragg grating 31 is etched and aligned with the transmission optical fiber 2, modulates the incident light wave and reflects it back to the transmission optical fiber 2;

[0047] The vibration component 4 is connected to the semiconductor structure 3 , senses the vibration of the object to be measured and transmits it to the Bragg grating 31 .

[0048] In this way, the light wave propagates inside the transmission optical fiber 2, and is injected into the semiconductor structure 3 through the position aligned with the semiconductor structure 3; the light wave is modulated in the Bragg grating 31 of the semiconductor structure 3, and the light wave that meets the reflection condition of the Bragg grating 31 is reflected back to the transmission optical fiber 2 through the aligned position; the light wave that does not meet the reflection condition of the Bragg grating 31 is transmitted out of the optical microstructure after extinction at the end of the semiconductor structure 3. At the same time, the vibration component 4 is set on the object to be measured. As the object to be measured vibrates, the vibration component 4 also vibrates, and is transmitted to the Bragg grating 31, causing it to produce micro deformations of stretching and compression. This micro deformation will change the length of the lattice period of the Bragg grating 31, thereby causing the reflected wavelength of the light wave modulated here to shift left and right near the original center wavelength of the reflected wave in the optical passband; that is, the wavelength of the light wave reflected back to the transmission optical fiber 2 will change back and forth.

[0049] In this way, by etching a Bragg grating 31 on the semiconductor structure 3, the semiconductor structure and the conducting optical fiber 2 are separated and arranged. In this way, when packaging is required, the semiconductor structure can be directly packaged, and there is no need to consider the problem of the bending radius of the optical fiber, thereby solving the problem that the bending radius of the optical fiber is too small and the packaged sensor size is too large; in addition, the semiconductor structure is more stable, thus solving the problem that the Bragg fiber grating is brittle and easy to break, and cannot measure high-frequency vibration signals.

[0050] In addition, the Bragg grating 31 is etched on the semiconductor, and there is no need to manufacture a Fabry-Perot optical resonant cavity on the semiconductor for measurement, thereby avoiding the problem of vibration signal distortion and inaccurate manufacturing process caused by the manufacturing error of the cavity length.

[0051] In this way, by etching the Bragg grating 31 on the semiconductor structure 3, the problem of the optical fiber bending radius being too small and the packaged sensor size being too large is solved, and the structure is stable, which is convenient for measuring high-frequency vibration signals. It should be additionally explained that for semiconductor and optical fiber materials, under the same reflectivity, the length of the fiber grating is longer, and the length of the Bragg grating of the semiconductor structure is shorter, so that the chip size of the optical acceleration sensor can be smaller; and due to material and manufacturing process problems, the fiber grating will gradually disappear in a long-term high-temperature environment. The Bragg grating manufacturing process of the semiconductor structure is different from that of the fiber grating, so it will not cause the problem of gradually disappearing in a high-temperature environment, so it can be applied to high-temperature, high-pressure, and high-frequency vibration scenarios.

[0052] Optional, such as Figure 1 As shown, the vibration component 4 is rigidly connected to the semiconductor structure 3. Thus, the vibration component 4 can cause the Bragg grating 31 to produce tensile and compressive micro deformations through vibration.

[0053] In this way, when the object under test vibrates, the vibration component 4 will vibrate in the vibration direction. Since the vibration component 4 is rigidly connected to the semiconductor structure 3, this vibration will cause the Bragg grating 31 to produce tensile and compressive micro-deformations, thereby affecting the wavelength of the reflected light wave.

[0054] Optionally, the vibration direction of the vibration component 4 is parallel to the length direction of the semiconductor structure 3, so that the vibration of the vibration component 4 will only cause the Bragg grating 31 to produce tensile and compressive micro-deformations, and will not produce deformations in other directions (deformations in other directions will cause nonlinear changes in the reflection and transmission effects of the Bragg grating 31, and easily cause the direction of light wave propagation to shift, thereby causing large errors in the measurement results).

[0055] Optionally, the Bragg grating 31 is etched on the semiconductor structure 3 .

[0056] In this way, the Bragg grating 31 is etched on the semiconductor structure 3 by etching, so that the stability and portability of the Bragg grating 31 can be increased (the etching process is mature and easy to process).

[0057] Optional, combined Figure 2 As shown, the central axis of the semiconductor structure 3 passes through the Bragg grating 31, so that the light waves propagating from the central axis and the vicinity of the central axis can be modulated by the Bragg grating 31, thereby improving the modulation effect.

[0058] Optionally, the center of mass of the vibration component 4 coincides with the center of the semiconductor structure 3. In this way, when the vibration component 4 vibrates, the vibration direction is parallel to the length direction (central axis) of the semiconductor structure 3, which will cause the Bragg grating 31 to deform only along the length direction without generating polarization.

[0059] It should be noted that polarization may cause the lattice period of the Bragg grating 31 to produce chirping stretching and compression, thereby greatly interfering with the accuracy of the acceleration sensor.

[0060] Optional, combined Figure 2 As shown, the vibration component 4 includes a mass block 41 and a cantilever arm 42 , and the mass block 41 is connected to the semiconductor structure 3 via the cantilever arm 42 .

[0061] In this way, the cantilever arm 42 constrains the vibration direction of the mass block 41. When the object to be measured vibrates, the mass block 41 vibrates in the vibration direction and causes the cantilever beam to bend and swing, thereby driving the Bragg grating 31 to produce a micro-deformation in the length direction.

[0062] In addition, by loading mass blocks 41 of different masses on the cantilever beam, the resolution of the acceleration value will be changed within a certain detection light bandwidth, thereby manufacturing acceleration sensors with different ranges, that is, large mass corresponds to small range, and small mass corresponds to large range. In this way, through the setting of the mass block 41, the range of the entire acceleration sensor can be adjusted and limited, thereby improving the measurement range and required accuracy of the acceleration sensor.

[0063] Optionally, there are multiple mass blocks 41 , and the masses of the mass blocks 41 are the same.

[0064] In this way, the uneven mass distribution of the entire vibration component 4 caused by the different masses of the mass block 41 can be avoided, thereby limiting the vibration direction of the mass block 41 and avoiding product polarization.

[0065] Optional, combined Figure 2 As shown, the cantilever arms 42 are of equal length and are radially and uniformly arranged around the semiconductor structure 3 .

[0066] The cantilever beams 42 are arranged uniformly and radially around the semiconductor structure 3, that is, one end of the cantilever beam 42 is fixed on the semiconductor structure 3, and the other end extends outward, and the angles between two adjacent cantilever beams 42 are the same. This arrangement can make the mass of the entire vibration component 4 evenly distributed, thereby limiting the vibration direction of the mass block 41 and avoiding product polarization.

[0067] Optional, combined Figure 2 As shown, the cantilever arm 42 and the mass block 41 are both located in the same plane, and the plane is perpendicular to the central axis of the semiconductor structure 3 (in the length direction); in this way, since one end of the cantilever arm 42 is fixed, the vibration of the other end (excluding the polarization caused by the different masses) can only be carried out along the direction in which the cantilever arm 42 can swing, that is, in a direction perpendicular to the cantilever arm 42 (parallel to the central axis of the semiconductor structure 3), thereby limiting the vibration direction to a direction parallel to the central axis of the semiconductor structure 3.

[0068] Optionally, the cantilever arm 42 and the mass block 41 are located in different planes (not shown in the figure), and each plane is perpendicular to the central axis of the semiconductor structure 3, and the cantilever arm 42 and the mass block 41 on each plane are evenly distributed; in this way, it can be ensured that the cantilever arm 42 and the mass block 41 on each plane only generate vibrations perpendicular to the central axis of the semiconductor structure 3, thereby ensuring that the overall vibration direction is also perpendicular to the central axis of the semiconductor structure 3.

[0069] Optionally, the number of the mass blocks 41 is four. Thus, the number of the cantilever arms 42 is also four, so that they are arranged in a cross shape on the semiconductor structure 3. Thus, the cross-shaped structure facilitates the processing and assembly of the semiconductor structure 3.

[0070] Optionally, the mass block 41, the cantilever arm 42, and the semiconductor structure 3 are integrated. In this way, the stability and processing difficulty are further improved (if not integrated, the processing difficulty is very high due to the small size).

[0071] Optional, combined Figure 2 As shown, a convex lens 5 is provided on one end of the transmission optical fiber 2 which is aligned with the Bragg grating 31 .

[0072] In this way, the light waves propagating in the transmission optical fiber 2 enter the semiconductor structure 3 in the form of parallel light through the convex lens 5; similarly, the light waves reflected by the Bragg grating 31 are focused into the transmission optical fiber 2 through the convex lens 5.

[0073] In addition, the structure can also be used to complete the alignment operation between the transmission optical fiber 2 and the Bragg grating 31. For example, during installation, the light wave is allowed to propagate in the transmission optical fiber 2, and then the energy of the reflected light wave is checked, and the positions of the transmission optical fiber 2 with the convex lens 5 and the Bragg grating 31 are adjusted forward and backward to make the observed reflected light wave reach the maximum value, that is, the alignment is correct.

[0074] Optionally, an anti-reflection film is attached to the cross section of the Bragg grating 31 (the cross section where the light wave enters), so that more light intensity can enter the Bragg grating 31 .

[0075] Optionally, a transmission film is attached to the end of the Bragg grating 31 or a waveguide extinction channel is provided at the end of the semiconductor structure 3 , so as to reduce the light waves reflected by other mirror surfaces except the Bragg grating 31 from returning to the signal demodulator 8 .

[0076] Optional, combined Figure 3 As shown, it also includes a packaging shell 6, which wraps the semiconductor structure 3 and the vibration component 4 and is fixedly connected to the conductive optical fiber 2.

[0077] In this way, the semiconductor structure 3 and the vibration component 4 are packaged through packaging, thereby facilitating protection and reducing processing difficulty.

[0078] Optionally, two or three package shells 6 are fixed orthogonally to each other (not shown in the figure), and the central axis of the semiconductor structure 3 in the package shell 6 is orthogonal and vertical. In this way, two or three packages can be integrated into a dual-axis acceleration sensor or a triaxial acceleration sensor, so as to measure the acceleration of the object under test in two or three directions in the environment.

[0079] Optionally, the transmission optical fiber 2 (convex lens 5) is fixed to the package shell 6 of the acceleration sensor by welding, so that the processing is convenient and the fixation is stable.

[0080] Optionally, the welding and fixing method is glass welding; in this way, welding is convenient and firm.

[0081] In this way, the processed optical acceleration sensor has the advantages of high vibration sensitivity, insensitivity to temperature, no zero drift, wide frequency response bandwidth, good linearity, etc.

[0082] To solve at least one aspect of the above technical problems to a certain extent, the present application also provides an optical acceleration sensor system, such as Figure 4 As shown, the optical acceleration sensor system includes the optical acceleration sensor 1 described above.

[0083] In this way, the semiconductor structure and the conducting optical fiber 2 are separated and arranged by etching a Bragg grating 31 on the semiconductor structure 3. In this way, when packaging is required, the semiconductor structure can be directly packaged, and there is no need to consider the problem of the bending radius of the optical fiber, thereby solving the problem that the bending radius of the optical fiber is too small and the packaged sensor size is too large; in addition, the semiconductor structure is more stable, thus solving the problem that the Bragg fiber grating is brittle and easy to break, and cannot measure high-frequency vibration signals.

[0084] Optional, such as Figure 4 As shown, the optical acceleration sensor system also includes:

[0085] A light source generator 7, which generates light waves for detection;

[0086] A signal demodulator 8, which demodulates the incident light wave into an electrical signal and calculates the corresponding acceleration;

[0087] An optical fiber coupler 9, one end of which is connected to the light source generator 7 and the signal demodulator 8 via optical fiber, and the other end of which is connected to the optical acceleration sensor 1 via optical fiber, separates the optical wave transmission channel of the optical acceleration sensor 1 into the optical wave transmission channel of the light source generator 7 and the optical wave transmission channel of the signal demodulator 8.

[0088] In this way, the light source generator 7 emits a light wave, and the light wave enters the fiber coupler 9 through the optical fiber; the fiber coupler 9 couples the laser into the optical fiber of the optical acceleration sensor 1, and after passing through the fiber coupler 9, the light wave is introduced into the optical acceleration sensor 1; the light wave whose wavelength meets the conditions of the Bragg grating 31 is reflected by the Bragg grating 31, and enters the fiber coupler 9 through the optical fiber of the optical acceleration sensor 1 again, and then enters the signal demodulator 8 through the fiber coupler 9; the optical acceleration sensor 1 is installed in the object or environment to be detected, if the physical quantity of the object or environment to be detected changes, then the wavelength of the light wave reflected at the optical acceleration sensor 1 will also change and be reflected back along the inside of the optical fiber, and the reflected wavelength passes through the fiber coupler 9 and enters the signal demodulator 8, and the signal demodulator 8 converts the optical signal of the reflected light wave into an electrical signal, and then calculates the corresponding physical quantity (acceleration) through a certain demodulation algorithm.

[0089] In this way, the acceleration of the object under test can be accurately measured through the optical acceleration sensor system, and the material of the semiconductor structure is more stable, which is more convenient for measuring in high temperature, high pressure or high frequency vibration environment. This makes the optical acceleration sensor system have high vibration sensitivity, insensitivity to temperature, no zero drift, wide frequency response bandwidth and good linearity.

[0090] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An optical acceleration sensor, characterized in that: include: A transmission optical fiber (2) in which light waves are transmitted; A semiconductor structure (3) on which a Bragg grating (31) is etched and aligned with the transmission optical fiber (2), modulating an incident light wave and then reflecting it back to the transmission optical fiber (2); A vibration component (4) connected to the semiconductor structure (3) to sense the vibration of the object to be measured and transmit it to the Bragg grating (31); A convex lens (5) is provided on one end of the transmission optical fiber (2) aligned with the Bragg grating (31); It also comprises a packaging shell (6), wherein the packaging shell (6) encapsulates the semiconductor structure (3) and the vibration component (4), and is fixedly connected to the conducting optical fiber (2).

2. The optical acceleration sensor according to claim 1, characterized in that: The center of mass of the vibration component (4) coincides with the center of the semiconductor structure (3).

3. The optical acceleration sensor according to any one of claims 1 to 2, characterized in that: The vibration component (4) comprises a mass block (41) and a cantilever arm (42); the mass block (41) is connected to the semiconductor structure (3) via the cantilever arm (42).

4. The optical acceleration sensor according to claim 3, characterized in that: There are a plurality of mass blocks (41), and the masses of the plurality of mass blocks (41) are the same.

5. The optical acceleration sensor according to claim 3, characterized in that: The cantilever arms (42) are of equal length and are radially and evenly arranged around the semiconductor structure (3).

6. The optical acceleration sensor according to claim 4, characterized in that: The number of the mass blocks (41) is four.

7. An optical acceleration sensor system, characterized in that: The optical acceleration sensor (1) comprises any one of claims 1 to 6.

8. The optical acceleration sensor system according to claim 7, characterized in that: Also includes: A light source generator (7) that generates light waves for detection; A signal demodulator (8) which demodulates the incident light wave into an electrical signal and calculates the corresponding acceleration; An optical fiber coupler (9) having one end connected to the light source generator (7) and the signal demodulator (8) via optical fibers, and having the other end connected to the optical acceleration sensor (1) via optical fibers, so as to separate the light wave transmission channel of the optical acceleration sensor (1) into the light wave transmission channel of the light source generator (7) and the light wave transmission channel of the signal demodulator (8).

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