Optical acoustic wave measuring device and system

Abstract

The invention relates to the technical field of sound wave detection, and discloses an optical sound wave measuring device and system. The device comprises a laser light source, an optical resonant cavity, a photoelectric conversion device and a light beam conversion assembly, the laser source is used for generating laser beams; the optical resonant cavity is used for enabling incident laser beams to generate interference; the photoelectric conversion device is used for converting an incident laser beam into an electric signal; light beam conversion assembly is used for converting a laser beam generated by a laser light source into a laser beam containing two polarization components with orthogonal polarization states and transmitting the laser beam to an optical resonant cavity, and converting the two polarization components in the laser beam output from the optical resonant cavity into polarization non-orthogonal components and transmitting the two polarization components to a photoelectric conversion device after interference. . According to the embodiment of the invention, the measurement sensitivity of film-free optical acoustic wave measurement can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of acoustic wave detection, and particularly to an optical acoustic wave measurement device and system. Background Art

[0002] The measurement sensitivity of a membrane-free optical acoustic wave measurement device is related to factors such as the finesse and peak transmittance of its optical resonator. The higher the finesse and / or the larger the peak transmittance, the higher the measurement sensitivity of the membrane-free optical acoustic wave measurement device. The finesse of the optical resonator is determined by the reflectivity of the inner mirror surface of the optical resonator. The higher the reflectivity of the inner mirror surface of the optical resonator, the larger the finesse of the optical resonator. However, affected by the processing technology, the higher the reflectivity of the optical resonator, the smaller the peak transmittance of the optical resonator, and as the reflectivity of the optical resonator increases, the peak transmittance of the optical resonator decreases exponentially, severely restricting the measurement sensitivity of the membrane-free optical acoustic wave measurement device. Summary of the Invention

[0003] The purpose of the present application is to provide an optical acoustic wave measurement device and system, aiming to improve the measurement sensitivity of membrane-free optical acoustic wave measurement.

[0004] An embodiment of the present application provides an optical acoustic wave measurement device, including: A laser light source for generating a laser beam; An optical resonator for interfering the incident laser beam; A photoelectric conversion device for converting the incident laser beam into an electrical signal; A beam conversion assembly connected to the laser light source, the optical resonator, and the photoelectric conversion device through optical fibers, for converting the laser beam generated by the laser light source into a laser beam containing two polarization components with orthogonal polarization states and transmitting it to the optical resonator, and converting the two polarization components in the laser beam output from the optical resonator into non-orthogonal polarization states and interfering them before transmitting them to the photoelectric conversion device.

[0005] In some embodiments, the beam conversion assembly is used to split the laser beam generated by the laser light source into two polarized laser beams with orthogonal polarization states and then combine them into a laser beam containing two polarization components with orthogonal polarization states, and is used to split the laser beam output from the optical resonator into two polarized laser beams with the same polarization state and then combine them into the corresponding laser beam.

[0006] In some embodiments, the beam conversion assembly includes two sets of polarization beam splitting and combining assemblies; One of the polarization beam splitting / combining components is connected between the laser light source and one of the resonant cavity walls of the optical resonant cavity through an optical fiber, and the other polarization beam splitting / combining component is connected between the other resonant cavity wall of the optical resonant cavity and the photoelectric conversion device through an optical fiber.

[0007] In some embodiments, the beam conversion component includes an optical circulator and a polarization beam splitting / combining component; The laser light source is connected to the first port of the optical circulator through an optical fiber, the polarization beam splitting / combining component is connected between the second port of the optical circulator and one of the resonant cavity walls of the optical resonant cavity through an optical fiber, and the photoelectric conversion device is connected to the third port of the optical circulator through an optical fiber; The signal path of the optical circulator is from the first port to the second port, from the second port to the third port, and from the third port to the first port.

[0008] In some embodiments, the polarization beam splitting / combining component includes a polarization beam splitter and a polarization combiner; The polarization beam splitter is configured to split the laser beam generated by the laser light source into two orthogonally polarized laser beams, and the polarization combiner is configured to combine the two orthogonally polarized laser beams split by the polarization beam splitter into a laser beam including two orthogonally polarized components; and / or The polarization beam splitter is configured to combine the two orthogonally polarized laser beams split by the polarization combiner into corresponding laser beams, and the polarization combiner is configured to split the laser beam output from the optical resonant cavity into two laser beams with the same polarization state.

[0009] In some embodiments, a collimator is disposed on the resonant cavity wall of the optical resonant cavity; The collimator, which is connected to the beam conversion component through an optical fiber, is configured to transmit the laser beam output from the beam conversion component to the optical resonant cavity and to re-transmit the laser beam output from the optical resonant cavity to the beam conversion component.

[0010] In some embodiments, the laser light source is a narrow linewidth tunable laser.

[0011] In some embodiments, the optical resonant cavity is a Fabry-Perot confocal resonant cavity.

[0012] An embodiment of the present application further provides an optical acoustic wave measurement system, including: The above-mentioned optical acoustic wave measurement device; A data processor, electrically connected to the photoelectric conversion device, for inverting the acoustic wave information in the optical resonant cavity according to the electrical signal converted by the photoelectric conversion device.

[0013] Advantages of the present application: The laser beam generated by the laser light source is first split into two laser beams with orthogonal polarization states by the beam conversion component and then combined into a laser beam containing two polarization components with orthogonal polarization states, so that when the polarization components with the same polarization state in the laser beam entering the optical resonator interfere after several reflections on the resonator wall in the optical resonator, no interference occurs between the two polarization components with orthogonal polarization states, and the two polarization components that interfere independently pass through the optical resonator and then are superimposed and transmitted to the beam conversion component through the optical fiber. The beam conversion component then converts the two polarization components in the laser beam output from the optical resonator into non-orthogonal polarization states and interferes. Compared with the interference of the two polarization components in the optical resonator or directly transmitting the laser beam generated by the laser light source to the optical resonator and then interfering in the optical resonator, the light transmittance of the method in which the two polarization components with orthogonal polarization states pass through the optical resonator independently is higher, and the measurement sensitivity of the film-free optical acoustic measurement can be improved. Description of the Drawings

[0014] Figure 1 It is a schematic structural diagram of an optical acoustic measurement device provided by the first embodiment of the present application.

[0015] Figure 2 It is a schematic structural diagram of an optical acoustic measurement device provided by the second embodiment of the present application.

[0016] Figure 3 It is a schematic structural diagram of an optical acoustic measurement device provided by the third embodiment of the present application.

[0017] Figure 4 It is a schematic diagram of the comparison of the light intensity transmitted through the optical resonator between the optical acoustic measurement device provided by the embodiment of the present application and the optical acoustic measurement device of the prior art.

[0018] Figure 5 It is a schematic structural diagram of an optical acoustic measurement system provided by the embodiment of the present application. Detailed Embodiments

[0019] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] It should be noted that the terms "first", "second", "third", "fourth", etc. (if any) in the description of this application and the above-mentioned drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a system, product, or device comprising a series of circuits need not be limited to those circuits clearly listed, but may include other circuits not clearly listed or inherent to these systems, products, or devices.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0022] An embodiment of this application provides an optical acoustic wave measuring device.

[0023] Referring to Figure 1 , in one embodiment, the optical acoustic wave measuring device includes a laser light source 100, an optical resonator 200, a photoelectric conversion device 300, and a beam conversion component 400. The laser light source 100 is used to generate a laser beam. The optical resonator 200 is used to cause the incident laser beam to interfere. The photoelectric conversion device 300 is used to convert the incident laser beam into an electrical signal. The beam conversion component 400 is connected to the laser light source 100, the optical resonator 200, and the photoelectric conversion device 300 through optical fibers. The beam conversion component 400 is used to convert the laser beam generated by the laser light source 100 into a laser beam including two polarization components with orthogonal polarization states and transmit it to the optical resonator 200, and convert the two polarization components in the laser beam output from the optical resonator 200 into non-orthogonal polarization states, and after interference, transmit it to the photoelectric conversion device 300.

[0024] In practical applications, the laser light source 100 generates a laser beam and transmits it through an optical fiber to the beam conversion component 400. The beam conversion component 400 converts the laser beam generated by the laser light source 100 into a laser beam containing two polarization components with orthogonal polarization states and transmits it through an optical fiber to the optical resonator 200. The polarization components with the same polarization state in the laser beam entering the optical resonator 200 interfere after undergoing multiple reflections on the resonator walls inside the optical resonator 200. The optical resonator 200 transmits the laser beam after interference through an optical fiber to the beam conversion component 400. The beam conversion component 400 converts the two polarization components in the laser beam output from the optical resonator 200 into non-orthogonal polarization states and then transmits it through an optical fiber to the photoelectric conversion device 300. Finally, the photoelectric conversion device 300 converts the incident laser beam into an electrical signal. Since the laser beam entering the optical resonator 200 contains two polarization components with orthogonal polarization states, when the polarization components with the same polarization state in the laser beam entering the optical resonator 200 interfere after undergoing multiple reflections on the resonator walls inside the optical resonator 200, the two polarization components with orthogonal polarization states do not interfere with each other. Finally, the two polarization components that interfere independently pass through the optical resonator 200 and are then superimposed through an optical fiber and transmitted to the beam conversion component 400. The beam conversion component 400 converts the two polarization components in the laser beam output from the optical resonator 200 into non-orthogonal polarization states. Compared with the case where the two polarization components interfere inside the optical resonator 200 or the laser beam generated by the laser light source 100 is directly transmitted to the optical resonator 200 and then interferes inside the optical resonator 200, the light transmittance of the method in which the two polarization components with orthogonal polarization states independently pass through the optical resonator 200 is higher. After the beam conversion component 400 converts the two polarization components in the laser beam output from the optical resonator 200 into non-orthogonal polarization states, interference occurs between the two polarization components with non-orthogonal polarization states in the laser beam. The beam conversion component 400 transmits the laser beam in which interference occurs between the two polarization components with non-orthogonal polarization states through an optical fiber to the photoelectric conversion device 300.

[0025] In some embodiments, the beam conversion component 400 is configured to split the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states and then combine them into a laser beam including two polarization components with orthogonal polarization states, and is also configured to split the laser beam output from the optical resonator 200 into two polarized laser beams with the same polarization state and then combine them into the corresponding laser beam. Specifically, first, the beam conversion component 400 makes the laser beam entering the optical resonator 200 include two polarization components with orthogonal polarization states by splitting the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states and then combining them into a laser beam including two polarization components with orthogonal polarization states. For the polarization components with the same polarization state in the laser beam entering the optical resonator 200, after undergoing multiple reflections on the resonator wall in the optical resonator 200, interference occurs, while no interference occurs between the two polarization components with orthogonal polarization states. First, the beam conversion component 400 splits the laser beam output from the optical resonator 200 into two polarized laser beams with the same polarization state and then combines them into the corresponding laser beam, so that the two polarization components with orthogonal polarization states in the laser beam output from the optical resonator 200 are converted into polarization states with the same polarization state, and then interference occurs and they are combined into the corresponding laser beam.

[0026] First, split the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states and then combine them into a laser beam including two polarization components with orthogonal polarization states. Then, split the laser beam output from the optical resonator 200 into two polarized laser beams with the same polarization state and then combine them into the corresponding laser beam. The calculation formula for the light intensity of the combined laser beam is: , , , Wherein, is the light intensity of the combined laser beam, is the first polarization component of the laser beam output from the optical resonator 200, is the second polarization component of the laser beam output from the optical resonator 200, is and the phase difference between, is the first polarization component of the laser beam input into the optical resonator 200, is the second polarization component of the laser beam input into the optical resonator 200, is the transmittance of the optical resonator 200.

[0027] Since and are obtained by splitting the same laser beam, therefore , the light intensity of the combined laser beam can be obtained as . Assuming that the two polarization components in the laser beam input to the optical resonator 200 are equal, that is , it can be obtained that , compared with directly transmitting the laser beam of the laser light source 100 to the optical resonator 200, the light intensity increases by . More specifically, referring to Figure 4 , in one embodiment, the light intensity of the finally obtained laser beam after beam splitting and combining in the above embodiment can be close to 1.8 mW, while the light intensity of the finally obtained laser beam by directly transmitting the laser beam of the laser light source 100 to the optical resonator 200 can only be close to 0.4 mW.

[0028] Referring to Figure 2 , in one embodiment, the beam conversion component 400 includes two sets of polarization beam splitting and combining components 410. Among them, one polarization beam splitting and combining component 410 is connected between the laser light source 100 and one resonator wall of the optical resonator 200 through an optical fiber, and the other polarization beam splitting and combining component 410 is connected between the other resonator wall of the optical resonator 200 and the photoelectric conversion device 300 through an optical fiber. Specifically, one polarization beam splitting and combining component 410 of the beam conversion component 400 is connected to the laser light source 100 through an optical fiber and splits the laser beam generated by the laser light source 100 into two orthogonally polarized laser beams and then combines them into a laser beam containing two orthogonally polarized components, and transmits the converted laser beam containing two orthogonally polarized components to one resonator wall of the optical resonator 200 through an optical fiber. The other polarization beam splitting and combining component 410 of the beam conversion component 400 is connected to the other resonator wall of the optical resonator 200 through an optical fiber and splits the laser beam output from the optical resonator 200 into two laser beams with the same polarization state and then combines them into the corresponding laser beam, and transmits the converted laser beam to the photoelectric conversion device 300 through an optical fiber.

[0029] Referring to Figure 3, in one embodiment, the beam conversion component 400 includes an optical circulator 420 and a polarization beam splitter / combiner component 410. Among them, the laser light source 100 is connected to the first port of the optical circulator 420 through an optical fiber, the polarization beam splitter / combiner component 410 is connected between the second port of the optical circulator 420 and one of the resonant cavity walls of the optical resonator 200 through an optical fiber, and the photoelectric conversion device 300 is connected to the third port of the optical circulator 420 through an optical fiber. The signal path of the optical circulator 420 is from the first port to the second port, from the second port to the third port, and from the third port to the first port. Specifically, the beam conversion component 400 first accesses the laser beam generated by the laser light source 100 through the optical circulator 420, splits the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states, and then combines them into a laser beam containing two polarization components with orthogonal polarization states. The converted laser beam containing two polarization components with orthogonal polarization states is transmitted to one of the resonant cavity walls of the optical resonator 200 through an optical fiber. Then, the laser beam output from the optical resonator 200 is accessed from this resonant cavity wall of the optical resonator 200, split into two polarized laser beams with the same polarization state, and then combined into the corresponding laser beam. The converted laser beam is transmitted to the photoelectric conversion device 300 through the optical circulator 420.

[0030] In some embodiments, the polarization beam splitter / combiner component 410 includes a polarization beam splitter device 411 and a polarization combiner device 412. The polarization beam splitter device 411 is used to split the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states, and the polarization combiner device 412 is used to combine the two polarized laser beams split by the polarization beam splitter device 411 into a laser beam containing two polarization components with orthogonal polarization states; and / or the polarization beam splitter device 411 is used to combine the two polarized laser beams split by the polarization combiner device 412 into the corresponding laser beam, and the polarization combiner device 412 is used to split the laser beam output from the optical resonator 200 into two polarized laser beams with the same polarization state. In the above Figure 2 embodiment, the polarization beam splitter device 411 is used to split the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states, and the polarization combiner device 412 is used to combine the two polarized laser beams split by the polarization beam splitter device 411 into a laser beam containing two polarization components with orthogonal polarization states. In the above Figure 3In the embodiments, the polarization beam splitting device 411 is configured to split the laser beam generated by the laser light source 100 into two polarized laser beams with orthogonal polarization states. The polarization beam combining device 412 is configured to combine the two polarized laser beams split by the polarization beam splitting device 411 into a laser beam including two polarization components with orthogonal polarization states. The polarization beam splitting device 411 is further configured to combine the two polarized laser beams split by the polarization beam combining device 412 into corresponding laser beams. The polarization beam combining device 412 is further configured to split the laser beam output from the optical resonator 200 into two polarized laser beams with the same polarization state.

[0031] Refer to Figure 2 and Figure 3 , in some embodiments, the resonator wall of the optical resonator 200 is configured with a collimator 500. Wherein, the collimator 500 is connected to the beam conversion component 400 through an optical fiber. The collimator 500 is configured to transmit the laser beam output from the beam conversion component 400 to the optical resonator 200 and to re-transmit the laser beam output from the optical resonator 200 to the beam conversion component 400, which can improve the directivity and spatial accuracy of the laser beam.

[0032] In some embodiments, the laser light source 100 is a narrow linewidth tunable laser, which can provide a laser beam with high purity and high stability, and at the same time allows flexible adjustment of the wavelength of the laser beam.

[0033] In some embodiments, the optical resonator 200 is a Fabry-Perot confocal resonator. When the frequency of the incident laser beam satisfies its resonance condition, a very high peak will appear in its transmission spectrum, corresponding to a very high transmittance, which can further improve the test sensitivity of the optical acoustic measurement device.

[0034] The embodiments of the present application further provide an optical acoustic measurement system.

[0035] Refer to Figure 5 , in one embodiment, the optical acoustic measurement system includes a data processor and the above-mentioned optical acoustic measurement device. The data processor is electrically connected to the photoelectric conversion device, and the data processor is configured to invert the acoustic wave information in the optical resonator based on the electrical signal converted by the photoelectric conversion device.

[0036] In summary, for the optical acoustic wave measuring device and system provided in the embodiments of the present application, the laser beam generated by the laser light source is first split into two laser beams with orthogonal polarization states by the beam conversion component and then combined into a laser beam containing two polarization components with orthogonal polarization states, so that when the polarization components with the same polarization state in the laser beam entering the optical resonator interfere after several reflections on the resonator wall in the optical resonator, no interference occurs between the two polarization components with orthogonal polarization states, and the two interfering polarization components independently pass through the optical resonator and then are superimposed and transmitted to the beam conversion component through the optical fiber. The beam conversion component then converts the two polarization components in the laser beam output from the optical resonator into non-orthogonal polarization states. Compared with the case where the two polarization components interfere in the optical resonator or the laser beam generated by the laser light source is directly transmitted to the optical resonator and then interferes in the optical resonator, the light transmittance of the method in which the two polarization components with orthogonal polarization states independently pass through the optical resonator is higher, which can improve the measurement sensitivity of the film-free optical acoustic wave measurement.

[0037] It should be understood that in this application, "at least one (item)" means one or more, and "multiple" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist at the same time. Here, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or a similar expression means any combination of these items, including any combination of single item (one) or multiple items (ones). For example, at least one (one) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0038] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, and thus do not limit the scope of rights of the embodiments of the present application. Any modification, equivalent replacement, and improvement made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of rights of the embodiments of the present application.

Claims

1. An optical acoustic wave measuring device, characterized in that, Comprising: A laser light source for generating a laser beam; An optical resonator for causing the incident laser beam to interfere; A photoelectric conversion device for converting the incident laser beam into an electrical signal; A beam conversion assembly connected to the laser light source, the optical resonator, and the photoelectric conversion device through optical fibers, for converting the laser beam generated by the laser light source into a laser beam including two polarization components with orthogonal polarization states and transmitting it to the optical resonator, and converting the two polarization components in the laser beam output from the optical resonator into non-orthogonal polarization states, interfering them, and then transmitting them to the photoelectric conversion device.

2. The optical acoustic wave measuring device according to claim 1, characterized in that, The beam conversion assembly is configured to split the laser beam generated by the laser light source into two polarized laser beams with orthogonal polarization states and then combine them into a laser beam including two polarization components with orthogonal polarization states, and is configured to split the laser beam output from the optical resonator into two polarized laser beams with the same polarization state and then combine them into the corresponding laser beam.

3. The optical acoustic measurement device according to claim 2, characterized in that, The beam conversion assembly includes two sets of polarization beam splitting and combining assemblies; One of the polarization beam splitting and combining assemblies is connected between the laser light source and one of the resonator walls of the optical resonator through an optical fiber, and the other polarization beam splitting and combining assembly is connected between the other resonator wall of the optical resonator and the photoelectric conversion device through an optical fiber.

4. The optical acoustic measurement device according to claim 2, characterized in that, The beam conversion assembly includes an optical circulator and a polarization beam splitting and combining assembly; The laser light source is connected to the first port of the optical circulator through an optical fiber, the polarization beam splitting and combining assembly is connected between the second port of the optical circulator and one of the resonator walls of the optical resonator through an optical fiber, and the photoelectric conversion device is connected to the third port of the optical circulator through an optical fiber. The signal path of the optical circulator is from the first port to the second port, from the second port to the third port, and from the third port to the first port.

5. The optical acoustic wave measuring device according to claim 3 or 4, characterized in that, The polarization beam splitting and combining assembly includes a polarization beam splitter and a polarization combiner; The polarization beam splitter is configured to split the laser beam generated by the laser light source into two polarized laser beams with orthogonal polarization states, and the polarization combiner is configured to combine the two polarized laser beams split by the polarization beam splitter into a laser beam including two polarization components with orthogonal polarization states; and / or The polarization beam splitter is configured to combine the two polarized laser beams split by the polarization combiner into the corresponding laser beam, and the polarization combiner is configured to split the laser beam output from the optical resonator into two polarized laser beams with the same polarization state.

6. The optical acoustic wave measuring device according to claim 1, characterized in that A collimator is disposed on the resonator wall of the optical resonator; The collimator, connected to the beam conversion assembly through an optical fiber, is configured to transmit the laser beam output from the beam conversion assembly to the optical resonator and to re-transmit the laser beam output from the optical resonator to the beam conversion assembly.

7. The optical acoustic wave measuring device according to claim 1, characterized in that, The laser light source is a narrow linewidth tunable laser.

8. The optical acoustic wave measuring device according to claim 1, characterized in that, The optical resonator is a Fabry-Perot confocal resonator.

9. An optical acoustic wave measurement system, characterized in that, Comprising: The optical acoustic wave measurement device according to any one of claims 1 to 8; A data processor, electrically connected to the photoelectric conversion device, is configured to invert the acoustic wave information in the optical resonator according to the electrical signal converted by the photoelectric conversion device.

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