Optical acoustic wave measurement device and system

Abstract

The present application relates to the field of acoustic wave detection technology and discloses an optical acoustic wave measurement device and system. The device includes a laser light source, an optical resonant cavity, a photoelectric conversion device, and a beam conversion assembly. The laser light source is used to generate a laser beam. The optical resonant cavity is used to cause interference of the incident laser beam. The photoelectric conversion device is used to convert the incident laser beam into an electrical signal. The beam conversion assembly is used to convert the laser beam generated by the laser light source into a laser beam containing two polarization components with orthogonal polarization states and transmit it to the optical resonant cavity, and to convert the two polarization components in the laser beam output from the optical resonant cavity into non-orthogonal polarization states, cause interference, and then transmit it to the photoelectric conversion device. Embodiments of the present application can improve the measurement sensitivity of membraneless optical acoustic wave measurements.

Description

Technical Field

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

[0002] The measurement sensitivity of a membraneless optical acoustic wave measurement device is related to factors such as the finesse and peak transmittance of its optical resonant cavity. The higher the finesse and / or the greater the peak transmittance, the higher the measurement sensitivity of the membraneless optical acoustic wave measurement device. The finesse of the optical resonant cavity is determined by the reflectivity of the internal mirror surfaces of the optical resonant cavity. The higher the reflectivity of the internal mirror surfaces of the optical resonant cavity, the greater the finesse of the optical resonant cavity. However, due to the influence of the processing technology, the higher the reflectivity of the optical resonant cavity, the lower the peak transmittance of the optical resonant cavity. Moreover, as the reflectivity of the optical resonant cavity increases, the peak transmittance of the optical resonant cavity decreases exponentially, which seriously restricts the measurement sensitivity of the membraneless optical acoustic wave measurement device. Summary of the Invention

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

[0004] The present invention provides an optical acoustic wave measuring device, comprising:

[0005] A laser light source, for generating a laser beam;

[0006] an optical resonant cavity for causing interference of incident laser beams;

[0007] A photoelectric conversion device for converting an incident laser beam into an electrical signal;

[0008] A beam conversion component connects the laser light source, the optical resonant cavity, and the photoelectric conversion device through an optical fiber, and is used to convert the laser light beam generated by the laser light source into a laser light beam containing two polarization components with orthogonal polarization states and transmit the laser light beam to the optical resonant cavity, and convert the two polarization components in the laser light beam output from the optical resonant cavity into non-orthogonal polarization states and transmit the non-orthogonal polarization components to the photoelectric conversion device after interference occurs.

[0009] In some embodiments, the beam conversion component is used to split the laser beam generated by the laser light source into two polarization 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 resonant cavity into two polarization laser beams with the same polarization state and then combine them into corresponding laser beams.

[0010] In some embodiments, the beam conversion component includes two sets of polarization beam splitting and combining components;

[0011] One of the polarization splitter / combiner 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 splitter / combiner component is connected between the other resonant cavity wall of the optical resonant cavity and the photoelectric conversion device through an optical fiber.

[0012] In some embodiments, the beam conversion component includes an optical circulator and a polarization beam splitter / combiner component;

[0013] The laser light source is connected to the first port of the optical circulator via an optical fiber, the polarization beam splitter / combiner is connected between the second port of the optical circulator and one of the resonant cavity walls of the optical resonator via an optical fiber, and the photoelectric conversion device is connected to the third port of the optical circulator via an optical fiber;

[0014] 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.

[0015] In some embodiments, the polarization beam splitting and combining assembly includes a polarization beam splitting device and a polarization beam combining device;

[0016] The polarization beam splitter is used to split the laser beam generated by the laser light source into two polarization laser beams with orthogonal polarization states, and the polarization beam combiner is used to combine the two polarization laser beams obtained by the polarization beam splitter into a laser beam containing two polarization components with orthogonal polarization states; and / or

[0017] The polarization beam splitter is used to combine the two polarization laser beams obtained by the polarization beam combiner into corresponding laser beams, and the polarization beam combiner is used to split the laser beam output from the optical resonant cavity into two polarization laser beams with the same polarization state.

[0018] In some embodiments, a resonant cavity wall of the optical resonant cavity is configured with a collimator;

[0019] The collimator is connected to the beam conversion component via an optical fiber, and is used to transmit the laser beam output by the beam conversion component to the optical resonant cavity and retransmit the laser beam output by the optical resonant cavity to the beam conversion component.

[0020] In some embodiments, the laser light source is a narrow linewidth tunable laser.

[0021] In some embodiments, the optical resonant cavity is a Fabry-Perot confocal resonant cavity.

[0022] The present invention also provides an optical acoustic wave measurement system, comprising:

[0023] The above-mentioned optical acoustic wave measuring device;

[0024] A data processor is electrically connected to the photoelectric conversion device and is used to invert the acoustic wave information in the optical resonant cavity according to the electrical signal converted by the photoelectric conversion device.

[0025] The beneficial effects of the present application are as follows: the laser beam generated by the laser light source is first split into two polarization laser beams with orthogonal polarization states through a beam conversion component, and then combined into a laser beam containing two polarization components with orthogonal polarization states, so that when the polarization components of the same polarization state in the laser beam entering the optical resonant cavity interfere after being reflected several times on the resonant cavity wall in the optical resonant cavity, the two polarization components with orthogonal polarization states do not interfere with each other, and the two polarization components that interfere with each other independently pass through the optical resonant cavity and are then 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 resonant cavity into non-orthogonal polarization states and interferes with each other. Compared with the interference of the two polarization components in the optical resonant cavity or the interference in the optical resonant cavity after the laser beam generated by the laser light source is directly transmitted to the optical resonant cavity, the transmittance of the two polarization components with orthogonal polarization states passing through the optical resonant cavity independently is higher, which can improve the measurement sensitivity of the membraneless optical acoustic wave measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the optical acoustic wave measurement device provided in the first embodiment of the present application.

[0027] Figure 2 It is a structural diagram of the optical acoustic wave measuring device provided in the second embodiment of the present application.

[0028] Figure 3 It is a structural diagram of the optical acoustic wave measurement device provided in the third embodiment of the present application.

[0029] Figure 4 3 is a schematic diagram comparing the light intensity transmitted through the optical resonant cavity between the optical acoustic wave measurement device provided in an embodiment of the present application and the optical acoustic wave measurement device of the prior art.

[0030] Figure 5 Schematic diagram of the structure of the optical acoustic wave measurement system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0032] It should be noted that the terms "first", "second", "third", "fourth", etc. (if any) in the specification of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a system, product or device that includes a series of circuits is not necessarily limited to those circuits clearly listed, but may include other circuits that are not clearly listed or inherent to these systems, products or devices.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0034] An embodiment of the present application provides an optical acoustic wave measuring device.

[0035] See Figure 1 In one embodiment, the optical acoustic wave measuring device includes a laser light source 100, an optical resonant cavity 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 resonant cavity 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 connects the laser light source 100, the optical resonant cavity 200, and the photoelectric conversion device 300 via an optical fiber. The beam conversion component 400 is used to convert the laser beam generated by the laser light source 100 into a laser beam containing two polarization components with orthogonal polarization states and transmit it to the optical resonant cavity 200, and convert the two polarization components in the laser beam output from the optical resonant cavity 200 into non-orthogonal polarization states, cause interference, and then transmit it to the photoelectric conversion device 300.

[0036] In actual application, the laser light source 100 generates laser light and transmits it to the beam conversion component 400 through optical fiber. 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 to the optical resonant cavity 200 through optical fiber. The polarization components with the same polarization state in the laser beam entering the optical resonant cavity 200 interfere after being reflected several times on the resonant cavity wall in the optical resonant cavity 200. The optical resonant cavity 200 transmits the interfered laser beam to the beam conversion component 400 through optical fiber. The beam conversion component 400 converts the two polarization components in the laser beam output from the optical resonant cavity 200 into non-orthogonal polarization states and then transmits it to the photoelectric conversion device 300 through optical fiber. Finally, the photoelectric conversion device 300 converts the incident laser beam into an electrical signal. Because the laser beam entering the optical resonant cavity 200 contains two polarization components with orthogonal polarization states, when the polarization components of the same polarization state in the laser beam entering the optical resonant cavity 200 interfere with each other after being reflected several times on the resonant cavity walls within the optical resonant cavity 200, the two polarization components with orthogonal polarization states do not interfere with each other. Ultimately, the two polarization components that interfere with each other independently pass through the optical resonant cavity 200, are superimposed via optical fiber, and are transmitted to the beam conversion assembly 400. The beam conversion assembly 400 converts the two polarization components in the laser beam output from the optical resonant cavity 200 into non-orthogonal polarization states. Compared to interference between the two polarization components within the optical resonant cavity 200 or direct transmission of the laser beam generated by the laser light source 100 to the optical resonant cavity 200 where they interfere within the optical resonant cavity 200, the method of having the two polarization components with orthogonal polarization states independently pass through the optical resonant cavity 200 has a higher light transmittance. After the beam conversion component 400 converts the two polarization components in the laser beam output from the optical resonant cavity 200 into non-orthogonal polarization states, interference occurs between the two non-orthogonal polarization components in the laser beam. The beam conversion component 400 transmits the laser beam with interference between the two non-orthogonal polarization components to the photoelectric conversion device 300 through an optical fiber.

[0037] In some embodiments, the beam conversion assembly 400 is used to split the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states and then combine them into a laser beam containing two polarization components with orthogonal polarization states, and to split the laser beam output from the optical resonant cavity 200 into two polarization laser beams with the same polarization state and then combine them into corresponding laser beams. Specifically, first, the beam conversion component 400 splits the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states and then combines them into a laser beam containing two polarization components with orthogonal polarization states, so that the laser beam entering the optical resonant cavity 200 contains two polarization components with orthogonal polarization states, and the polarization components with the same polarization state in the laser beam entering the optical resonant cavity 200 interfere after being reflected several times on the resonant cavity wall of the optical resonant cavity 200, while the two polarization components with orthogonal polarization states do not interfere with each other. First, the beam conversion component 400 splits the laser beam output from the optical resonant cavity 200 into two polarization laser beams with the same polarization state and then combines them into corresponding laser beams, so that the two polarization components with orthogonal polarization states in the laser beam output from the optical resonant cavity 200 are converted into polarization components with the same polarization state, and then interfere and combine into corresponding laser beams.

[0038] First, the laser beam generated by the laser light source 100 is split into two polarization laser beams with orthogonal polarization states and then combined into a laser beam containing two polarization components with orthogonal polarization states. Then, the laser beam output from the optical resonant cavity 200 is split into two polarization laser beams with the same polarization state and then combined into corresponding laser beams. The light intensity of the combined laser beam is calculated as follows:

[0039] ,

[0040] ,

[0041] ,

[0042] in, is the intensity of the combined laser beam, is the first polarization component of the laser beam output from the optical resonant cavity 200, is the second polarization component of the laser beam output from the optical resonant cavity 200, for and The phase difference between is the first polarization component of the laser beam input into the optical resonant cavity 200, is the second polarization component of the laser beam input into the optical resonant cavity 200, is the transmittance of the optical resonant cavity 200.

[0043] because and is obtained by splitting the same laser beam, so , the intensity of the combined laser beam can be obtained as Assume that the two polarization components of the laser beam input into the optical resonator 200 are equal, that is, , we can get Compared with directly transmitting the laser beam of the laser light source 100 to the optical resonant cavity 200, the light intensity is increased. For more details, see Figure 4 In one embodiment, the intensity of the laser beam finally obtained after beam splitting and combining according to the above embodiment can be close to 1.8 mW, while the intensity of the laser beam finally obtained by directly transmitting the laser beam of the laser light source 100 to the optical resonant cavity 200 can only be close to 0.4 mW.

[0044] See Figure 2 In one embodiment, the beam conversion assembly 400 includes two sets of polarization splitter / combiner assemblies 410. One of the polarization splitter / combiner assemblies 410 is connected between the laser light source 100 and one resonant cavity wall of the optical resonant cavity 200 via an optical fiber, and the other polarization splitter / combiner 410 is connected between the other resonant cavity wall of the optical resonant cavity 200 and the photoelectric conversion device 300 via an optical fiber. Specifically, one polarization splitter / combiner 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 polarization laser beams with orthogonal polarization states and then combines them into a laser beam containing two polarization components with orthogonal polarization states, and transmits the converted laser beam containing two polarization components with orthogonal polarization states to one resonant cavity wall of the optical resonant cavity 200 through an optical fiber, and another polarization splitter / combiner component 410 of the beam conversion component 400 is connected to the other resonant cavity wall of the optical resonant cavity 200 through an optical fiber and splits the laser beam output from the optical resonant cavity 200 into two polarization laser beams with the same polarization state and then combines them into corresponding laser beams, and transmits the converted laser beam to the photoelectric conversion device 300 through an optical fiber.

[0045] See Figure 3In one embodiment, the beam conversion assembly 400 includes an optical circulator 420 and a polarization beam splitter / combiner assembly 410. The laser light source 100 is connected to the first port of the optical circulator 420 via an optical fiber. The polarization beam splitter / combiner assembly 410 is connected between the second port of the optical circulator 420 and one of the resonant cavity walls of the optical resonator 200 via an optical fiber. The optoelectronic conversion device 300 is connected to the third port of the optical circulator 420 via 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 and splits the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states, which are then combined 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 resonant cavity 200 through an optical fiber. Then, the laser beam output from the optical resonant cavity 200 is accessed from the resonant cavity wall of the optical resonant cavity 200 and the laser beam output from the optical resonant cavity 200 is split into two polarization laser beams with the same polarization state, which are then combined into corresponding laser beams. The converted laser beam is transmitted to the photoelectric conversion device 300 through the optical circulator 420.

[0046] In some embodiments, the polarization beam splitting and combining component 410 includes a polarization beam splitter 411 and a polarization beam combiner 412. The polarization beam splitter 411 is used to split the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states, and the polarization beam combiner 412 is used to combine the two polarization laser beams obtained by the polarization beam splitter 411 into a laser beam containing two polarization components with orthogonal polarization states; and / or the polarization beam splitter 411 is used to combine the two polarization laser beams obtained by the polarization beam combiner 412 into corresponding laser beams, and the polarization beam combiner 412 is used to split the laser beam output from the optical resonator 200 into two polarization laser beams with the same polarization state. In the above Figure 2 In the embodiment, the polarization beam splitter 411 is used to split the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states, and the polarization beam combiner 412 is used to combine the two polarization laser beams obtained by the polarization beam splitter 411 into a laser beam containing two polarization components with orthogonal polarization states. Figure 3In an embodiment, the polarization beam splitter 411 is used to split the laser beam generated by the laser light source 100 into two polarization laser beams with orthogonal polarization states, and the polarization beam combiner 412 is used to combine the two polarization laser beams obtained by the polarization beam splitter 411 into a laser beam containing two polarization components with orthogonal polarization states. The polarization beam splitter 411 is also used to combine the two polarization laser beams obtained by the polarization beam combiner 412 into corresponding laser beams. The polarization beam combiner 412 is also used to split the laser beam output from the optical resonator 200 into two polarization laser beams with the same polarization state.

[0047] See Figure 2 and Figure 3 In some embodiments, a collimator 500 is configured on the resonant cavity wall of the optical resonant cavity 200. The collimator 500 is connected to the beam conversion component 400 via an optical fiber. The collimator 500 is used to transmit the laser beam output by the beam conversion component 400 to the optical resonant cavity 200 and to retransmit the laser beam output by the optical resonant cavity 200 to the beam conversion component 400, thereby improving the directionality and spatial accuracy of the laser beam.

[0048] In some embodiments, the laser light source 100 is a narrow linewidth tunable laser, which can provide a high-purity and high-stability laser beam while allowing for flexible adjustment of the laser beam wavelength.

[0049] In some embodiments, the optical resonant cavity 200 is a Fabry-Perot confocal resonant cavity. When the frequency of the incident laser beam meets its resonance condition, its transmission spectrum will have a very high peak, corresponding to a very high transmittance, which can further improve the test sensitivity of the optical acoustic wave measurement device.

[0050] An embodiment of the present application also provides an optical acoustic wave measurement system.

[0051] See Figure 5 In one embodiment, an optical acoustic wave measurement system includes a data processor and the aforementioned optical acoustic wave measurement device. The data processor is electrically connected to the photoelectric conversion device and is configured to invert acoustic wave information in the optical resonant cavity based on an electrical signal converted by the photoelectric conversion device.

[0052] In summary, the optical acoustic wave measurement device and system provided in the embodiments of the present application first split the laser beam generated by the laser light source into two polarization states of laser beams with orthogonal polarization states through a beam conversion component, and then combine them into a laser beam containing two polarization components with orthogonal polarization states. When the polarization components of the laser beam with the same polarization state entering the optical resonant cavity interfere with each other after being reflected several times on the resonant cavity wall in the optical resonant cavity, the two polarization components with orthogonal polarization states do not interfere with each other. The two polarization components that interfere with each other independently pass through the optical resonant cavity, are superimposed via an optical fiber, and are transmitted to the beam conversion component. The beam conversion component then converts the two polarization components in the laser beam output from the optical resonant cavity into non-orthogonal polarization states. Compared with the interference of the two polarization components in the optical resonant cavity or the interference in the optical resonant cavity after the laser beam generated by the laser light source is directly transmitted to the optical resonant cavity, the light transmittance of the two polarization components with orthogonal polarization states independently passing through the optical resonant cavity is higher, which can improve the measurement sensitivity of the membraneless optical acoustic wave measurement.

[0053] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least 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.

[0054] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. An optical acoustic wave measuring device, characterized in that: include: A laser light source, for generating a laser beam; an optical resonant cavity for causing interference of incident laser beams; A photoelectric conversion device for converting an incident laser beam into an electrical signal; a beam conversion assembly, connecting the laser light source, the optical resonant cavity, and the photoelectric conversion device via an optical fiber, for converting the laser light beam generated by the laser light source into a laser light beam containing two polarization components with orthogonal polarization states and transmitting the laser light beam to the optical resonant cavity, and for converting the two polarization components in the laser light beam output from the optical resonant cavity into non-orthogonal polarization states, causing interference, and then transmitting the non-orthogonal polarization components to the photoelectric conversion device; The beam conversion component is used to split the laser beam generated by the laser light source into two polarization 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 resonant cavity into two polarization laser beams with the same polarization state and then combine them into corresponding laser beams; The optical beam conversion component includes two groups of polarization splitting and combining components, one of which is connected between the laser light source and one resonant cavity wall of the optical resonant cavity through an optical fiber, and the other is connected between the other resonant cavity wall of the optical resonant cavity and the photoelectric conversion device through an optical fiber; or the optical beam conversion component includes an optical circulator and a polarization splitting and combining component, the laser light source is connected to a first port of the optical circulator through an optical fiber, the polarization splitting and combining component is connected between a second port of the optical circulator and one resonant cavity wall of the optical resonant cavity through an optical fiber, and the photoelectric conversion device is connected to a third port of the optical circulator through an optical fiber, and 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; The optical resonant cavity is a Fabry-Perot confocal resonant cavity.

2. The optical acoustic wave measuring device according to claim 1, wherein The polarization beam splitting and combining component includes a polarization beam splitting device and a polarization beam combining device; The polarization beam splitter is used to split the laser beam generated by the laser light source into two polarization laser beams with orthogonal polarization states, and the polarization beam combiner is used to combine the two polarization laser beams obtained by the polarization beam splitter into a laser beam containing two polarization components with orthogonal polarization states; and / or The polarization beam splitter is used to combine the two polarization laser beams obtained by the polarization beam combiner into corresponding laser beams, and the polarization beam combiner is used to split the laser beam output from the optical resonant cavity into two polarization laser beams with the same polarization state.

3. The optical acoustic wave measuring device according to claim 1, wherein The resonant cavity wall of the optical resonant cavity is provided with a collimator; The collimator is connected to the beam conversion component via an optical fiber, and is used to transmit the laser beam output by the beam conversion component to the optical resonant cavity and retransmit the laser beam output by the optical resonant cavity to the beam conversion component.

4. The optical acoustic wave measuring device according to claim 1, wherein The laser light source is a narrow linewidth tunable laser.

5. An optical acoustic wave measurement system, characterized in that: include: The optical acoustic wave measuring device according to any one of claims 1 to 4; A data processor is electrically connected to the photoelectric conversion device and is used to invert the acoustic wave information in the optical resonant cavity according to the electrical signal converted by the photoelectric conversion device.

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