High-frequency microphone system and working point control method thereof

Abstract

The invention discloses a high-frequency microphone system and a working point control method thereof. The system comprises a sensing probe, an optical fiber interferometer, a photoelectric conversion module, an interference signal demodulation module, a light source compensation module and a synchronization module. The optical fiber interferometer comprises a scanning light source, a tunable light source, a beam combiner, a circulator and a wavelength division multiplexer; the system comprises a sensing light path and a feedback light path. According to the sensing light path, a tunable light source emits a first light beam to a sensing probe after passing through a circulator, a sound wave signal is modulated to the first light beam to obtain a modulation signal, the modulation signal is converted into a first electric signal through a photoelectric conversion module, the first electric signal is input into an interference signal demodulation module to demodulate the sound wave signal to be input into a synchronization module, and a target sound signal is obtained; according to the feedback light path, the scanning light source emits a second light beam to the sensing probe through the circulator, the second light beam is interfered and then is converted into a second electric signal through the photoelectric conversion module, the second electric signal is input into the light source compensation module to generate a compensation light beam, and the compensation light beam enters the interferometer to adjust a working point.

Description

Technical Field

[0001] The present invention mainly relates to optical fiber acoustic sensing technology, and in particular to a high-frequency microphone system and a working point control method thereof. Background Art

[0002] Microphones are the most common sound signal collection tool in people's daily lives. Since their invention, they have undergone decades of development. As the technology of traditional electrical microphones has become increasingly perfect and mature, microphones are no longer limited to their past application fields. They have begun to undertake a variety of new applications such as acoustic sensing, speech recognition, sonar detection, ultrasonic non-destructive testing, etc., and have played an important role in people's livelihood, scientific research, medical care, industry and other fields.

[0003] Traditional microphones convert sound wave vibrations into electrical signals based on the characteristics of coupling materials. This type of microphone has certain limitations, such as low sensitivity, narrow frequency band, susceptibility to interference, easy introduction of noise, and poor confidentiality. In addition, in some complex environments, such as the strong magnetic field of a nuclear magnetic resonance apparatus and underwater environments, traditional electrical microphones cannot be used.

[0004] Therefore, how to design a microphone system with high sensitivity, large bandwidth, adaptability to complex environments, not susceptible to interference, and good noise confidentiality is a technical problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a high-frequency microphone system and a working point control method thereof to address the problems of the prior art.

[0006] In the first aspect, the embodiment of the present application provides a high-frequency microphone system, including a sensor probe 1, a fiber interferometer 2, a photoelectric conversion module 3, an interference signal demodulation module 4, a light source compensation module 5, and a synchronization module 6; the fiber interferometer 2 includes a scanning light source 21, a tunable light source 22, a beam combiner 23, a circulator 24, and a wavelength division multiplexer 25; The high-frequency microphone system includes a sensing optical path and a feedback optical path; Among them, the sensing optical path is: the tunable light source 22 emits a first light beam, the first light beam passes through the circulator 24 and reaches the sensing probe 1, the sensing probe 1 is used to modulate the collected acoustic wave signal onto the first light beam to obtain a modulated signal, the modulated signal passes through the circulator 24 and reaches the photoelectric conversion module 3 to be converted into a first electrical signal, the first electrical signal is input to the interference signal demodulation module 4 to demodulate the acoustic wave signal, the demodulated acoustic wave signal is input to the synchronization module 6, and the target acoustic signal is output; Among them, the feedback optical path is: the scanning light source 21 emits a second light beam, the second light beam passes through the circulator 24 and reaches the sensor probe 1, the second light beam interferes with the sensor probe 1 and reaches the photoelectric conversion module 3 through the circulator 24 to be converted into a second electrical signal, the second electrical signal is input into the light source compensation module 5 to generate a compensation light beam, and the compensation light beam is emitted into the fiber interferometer 2 to adjust the working point of the high-frequency microphone system.

[0007] Preferably, the sensing probe 1 is a high reflectivity FP cavity, comprising two high reflectivity mirrors.

[0008] Preferably, the fiber optic interferometer 2 is a fiber FP interferometer.

[0009] Preferably, the sensor probe 1 is used to modulate the collected acoustic wave signal onto a first light beam to obtain a first modulated signal, including: The sensing probe 1 acquires an external acoustic wave signal, which changes the refractive index of the air in the high-reflectivity FP cavity to cause the phase of the first light beam to change, and then interferes in the sensing probe 1 to form a first modulated signal.

[0010] Preferably, the photoelectric conversion module includes a first photodetector and a second photodetector.

[0011] Preferably, the first electrical signal and the second electrical signal are both analog electrical signals.

[0012] In a second aspect, an embodiment of the present application provides a method for controlling an operating point of a high-frequency microphone system as described in the first aspect, comprising the following steps: S1: Control the scanning light source 21 to perform wavelength scanning within the frequency band, and collect the output light intensity of the light beam passing through the sensor probe 1; S2: based on the corresponding relationship between the scanning wavelength of the scanning light source 21 and the output light intensity, obtaining the actual working point wavelength of the sensor probe 1; S3: Based on the actual working point wavelength and the initial calibration working point wavelength, obtaining the wavelength deviation of the sensor working point; S4: configuring the frequency band range of the tunable light source 22 based on the wavelength deviation so that the high-frequency microphone system is always at the working point.

[0013] Preferably, step S2 comprises: S21: based on the corresponding relationship between the scanning wavelength of the scanning light source 21 and the output light intensity, draw a reflection spectrum of the high reflectivity FP cavity; S22: determine all the maximum points of the reflection spectrum of the high reflectivity FP cavity; S23: Obtain the wavelengths corresponding to all maximum points at 75% output light intensity, and obtain multiple intermediate wavelengths; S24: taking the average value of the plurality of intermediate wavelengths as the actual working point wavelength of the sensing probe 1 .

[0014] Compared with the prior art, the high-frequency optical microphone of the present invention directly uses the light beam to detect the change of the air refractive index caused by the sound wave to realize the dynamic detection of the sound wave. It converts the change of the interference spectrum intensity into a voltage signal for demodulation based on the intensity demodulation technology, and has the advantages of fast demodulation speed, good real-time dynamics, simple system, high sensitivity, etc., and has the following beneficial effects: (1) High-sensitivity FP cavity acoustic wave sensing The high-sensitivity FP cavity is composed of two high-reflectivity surfaces to form an optical resonant cavity. When an acoustic wave enters the cavity, it causes a change in the refractive index of the air between the reflectors, thereby changing the phase of the output light. The change in the intensity of the output light is related to the frequency and intensity of the acoustic wave. A systematic mathematical model has been established for the acoustic sensing high-reflectivity FP cavity, which can quickly and thoroughly complete the design of the FP cavity according to requirements.

[0015] (2) Dynamic negative feedback intensity interference demodulation By dynamically adjusting the working state of the interferometer, the sensor sensitivity is kept at the maximum and unchanged, so as to track the changes caused by the sound wave in real time. A wavelength division dual-path interference system is adopted, one for sound wave detection and one for working point adjustment. A dynamic negative feedback system is formed by combining a high-speed signal processing board and PID negative feedback software control to ensure the effective extraction of interference signals in a rapidly changing sound wave environment.

[0016] (3) High-speed acoustic signal processing The demodulation performance of high-speed acoustic signals mainly depends on the suppression of phase noise. The phase noise of active devices in the entire system will be superimposed on the final output acoustic signal. By establishing a systematic noise transfer model and combining high-speed demodulation board differential signal suppression, optical active device noise suppression and other technologies, the background noise of high-frequency optical microphone instruments can be effectively controlled and the signal-to-noise ratio of the output signal can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By referring to the following drawings, the exemplary embodiments of the present invention can be more completely understood. The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present invention and do not constitute a limitation of the present invention. In the drawings, the same reference numerals generally represent the same parts or steps.

[0018] Figure 1 A schematic diagram of the structure of a high-frequency microphone system provided in an embodiment of the present application; Figure 2 A working principle diagram of a sensor probe provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of a fiber optic interferometer provided in an embodiment of the present application; Figure 4 A flowchart of a method for controlling an operating point of a high-frequency microphone system provided in an embodiment of the present application; Figure 5 A schematic diagram of operating point control of a high-frequency microphone system provided in an embodiment of the present application; Figure 6 A schematic diagram of operating point control of a high-frequency microphone system provided in an embodiment of the present application.

[0019] Reference numerals 1-sensing probe, 2-fiber interferometer, 3-photoelectric conversion module, 4-interference signal demodulation module, 5-light source compensation module, 6-synchronization module, 21-scanning light source, 22-tunable light source, 23-beam combiner, 24-circulator, 25-wavelength division multiplexer. DETAILED DESCRIPTION

[0020] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0022] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example 1 Reference Figure 1 This embodiment discloses a high-frequency microphone system, including a sensor probe 1 and a demodulator, wherein the main body of the demodulator includes a fiber interferometer 2, a photoelectric conversion module 3, an interference signal demodulation module 4, a light source compensation module 5, and a synchronization module 6; the demodulator also includes a power supply, an interface and a device control module.

[0024] Specifically, the sensing probe 1 is a high reflectivity FP cavity, including two high reflectivity mirrors to form an optical resonant cavity. Figure 2 The working principle of the sensor probe of the present application is given. An FP cavity is formed between two reflecting surfaces. The refractive index of the air in the cavity changes under the pressure or pressure of the outside world, which is equivalent to the change of the optical path of the light in the FP cavity. In this way, the size of the external sound wave can be obtained by demodulating the optical path of the FP. When the sound wave enters the cavity, it will cause the change of the refractive index of the air between the reflectors, thereby changing the intensity of the output light. The present invention realizes the detection of sound signals based on the small change of the refractive index of the air caused by the FP cavity detecting the sound wave.

[0025] Reference Figure 3 The optical fiber interferometer 2 of the present application is an optical fiber FP interferometer, including a scanning light source 21, a tunable light source 22, a beam combiner 23, a circulator 24 and a wavelength division multiplexer (ie, WDM) 25. The optical fiber interferometer 2 is based on the classic optical fiber FP interferometer structure, and uses wavelength division multiplexing technology to couple the light of two light sources of different wavelengths into the optical fiber and combine them, and then pass through the circulator to reach the sensor probe. The reflected light of the sensor probe passes through the optical fiber circulator and is wavelength-divided by WDM25, and then enters different photodetectors. The scanning light source 21 continuously outputs laser light with changing wavelengths, which is used for real-time scanning of the FP cavity reflection spectrum. The tunable light source 22 outputs narrow linewidth laser light, and its wavelength range can be 1528-1532nm, which is used for sensing the refractive index change of the FP cavity. The beam combiner and WDM are used for combining and splitting the two light sources respectively, and the circulator plays the role of optical path conversion in the optical path. The wavelengths of the two light sources in this embodiment belong to the C band and can be transmitted in a wavelength division multiplexing system composed of single-mode optical fiber devices without crosstalk.

[0026] Specifically, the photoelectric conversion module 3 includes a first photodetector and a second photodetector.

[0027] Specifically, the interference signal demodulation module 4 demodulates the acoustic signal from the first interference electrical signal. In a preferred embodiment, the interference signal demodulation module 4 can be a structure with a ZYQN main control chip as the core, and its periphery is equipped with AD, DA, network port, serial port, IO port and other peripherals to realize photoelectric conversion, digital-to-analog conversion, analog-to-digital conversion, communication, control and other functions.

[0028] The device control module controls the internal active devices, the power supply supplies power to the internal devices, and the interface module communicates with the outside.

[0029] The high-frequency microphone system of this embodiment includes a sensing optical path and a feedback optical path: (1) The sensing optical path is as follows: the tunable light source 22 emits a first light beam, which passes through the circulator 24 and reaches the sensing probe 1. The sensing probe 1 is used to modulate the collected acoustic wave signal onto the first light beam to obtain a modulated signal. The modulated signal passes through the circulator 24 and reaches the photoelectric conversion module 3 to be converted into a first electrical signal. The first electrical signal is input to the interference signal demodulation module 4 to demodulate the acoustic wave signal. The demodulated acoustic wave signal is input to the synchronization module 6 to obtain the target acoustic signal. When the system works at point Q, at a point centered at point Q, The acoustic signal is proportional to the light intensity, so in the acoustic signal demodulation module of this system, the acoustic phase signal can be obtained by simply dividing the collected light intensity by a coefficient.

[0030] (2) The feedback optical path is as follows: the scanning light source 21 emits a second light beam, the second light beam passes through the circulator 24 and reaches the sensor probe 1, the second light beam interferes with the sensor probe 1 and passes through the circulator 24 to reach the photoelectric conversion module 3 to be converted into a second electrical signal, the second electrical signal is input into the light source compensation module 5 to generate a compensation light beam, and the compensation light beam is emitted into the fiber interferometer 2 to adjust the working point of the high-frequency microphone system.

[0031] Compared with the prior art, the high-frequency optical microphone of the present invention directly uses the light beam to detect the change of the air refractive index caused by the sound wave to realize the dynamic detection of the sound wave. It converts the change of the interference spectrum intensity into a voltage signal for demodulation based on the intensity demodulation technology. It has the advantages of fast demodulation speed, good real-time dynamics, simple system, high sensitivity, etc., and has the following effective effects: (1) High-sensitivity FP cavity acoustic wave sensing The high-sensitivity FP cavity is composed of two high-interference-reflectivity mirrors to form an optical resonant cavity. When an acoustic wave enters the cavity, it causes a change in the refractive index of the air between the mirrors, thereby changing the phase of the output light. The change in the intensity of the output light is related to the frequency and intensity of the acoustic wave. A systematic mathematical model has been established for the acoustic sensing high-reflectivity FP cavity, which can quickly and thoroughly complete the design of the FP cavity according to requirements.

[0032] (2) Dynamic negative feedback intensity interference demodulation By dynamically adjusting the working state of the interferometer, the sensor sensitivity is kept at the maximum and unchanged, so as to track the changes caused by the sound wave in real time. A wavelength division dual-path interference system is adopted, one for sound wave detection and one for working point adjustment. A dynamic negative feedback system is formed by combining a high-speed signal processing board and PID negative feedback software control to ensure the effective extraction of interference signals in a rapidly changing sound wave environment.

[0033] (3) High-speed acoustic signal processing The demodulation performance of high-speed acoustic signals mainly depends on the suppression of phase noise. The phase noise of active devices in the entire system will be superimposed on the final output acoustic signal. By establishing a systematic noise transfer model and combining high-speed demodulation board differential signal suppression, optical active device noise suppression and other technologies, the background noise of high-frequency optical microphone instruments can be effectively controlled and the signal-to-noise ratio of the output signal can be improved.

[0034] Example 2 Based on the above embodiments, refer to Figure 4 , this embodiment provides a working point control method of a high frequency microphone, comprising the following steps: S1: Control the scanning light source 21 to perform wavelength scanning within the frequency band, and collect the output light intensity of the light beam passing through the sensor probe 1; S2: based on the corresponding relationship between the scanning wavelength of the scanning light source 21 and the output light intensity, obtaining the actual working point wavelength of the sensor probe 1; S3: Based on the actual working point wavelength and the initial calibration working point wavelength, the wavelength deviation of the sensor working point is obtained; S4: configuring the frequency band range of the tunable light source 22 based on the wavelength deviation so that the high-frequency microphone system is always at the working point.

[0035] When calculating the actual working point wavelength, the wavelength deviation of the corresponding wavelength can be obtained by calculating the peak value of the scanning light source 21 under different environmental influences such as temperature. , based on multiple different wavelength deviations, a total wavelength deviation is finally formed.

[0036] Wherein, step S2 comprises: S21: based on the corresponding relationship between the scanning wavelength and the output light intensity of the scanning light source 21, draw the reflection spectrum of the high reflectivity FP cavity; S22: determine all the maximum points of the reflection spectrum of the high reflectivity FP cavity; S23: Obtain the wavelengths corresponding to all maximum points at 75% output light intensity, and obtain multiple intermediate wavelengths; S24: Taking the average value of the multiple intermediate wavelengths as the actual working point wavelength of the sensor probe 1.

[0037] Specifically, the working point, that is, the working wavelength, works at the orthogonal point (Q point) where the slope of the interference spectrum is the largest, and the FPI exhibits a linear response and maximum sensitivity. During the signal demodulation process, the working wavelength of the input light should be kept at the Q point to achieve high sensitivity and linear response of the system. The current purpose of working point control is to ensure that the system can work stably at the Q point position without external sound signal input.

[0038] In this embodiment, the working point control method uses two scanning light sources. The tunable light source 22 is controlled to scan the wavelength within a specified range, and the output light intensity after passing through the FP cavity is collected at the same time; according to the corresponding relationship between the scanning wavelength and the output light intensity, the corresponding wavelength when the light intensity is 75% of the maximum value can be found to obtain the working point wavelength of the FP cavity acoustic sensor; the calculated working point wavelength is configured on the scanning light source 21 to make the system work at the working point Q.

[0039] Figure 5 and Figure 6 The working point control principle is shown in the figure, which includes the following steps: (1) The working point control method uses two scanning light sources. The tunable light source 22 is controlled to scan the wavelength within a specified range, and the output light intensity after passing through the FP cavity is collected at the same time. The relationship curve between the scanning wavelength and the light intensity can be shown as follows: Figure 5 As shown, the wavelength range of the scanning light source used in this system is 4nm, so multiple peaks can be scanned; (2) According to the corresponding relationship between the scanning wavelength and the output light intensity, the wavelength corresponding to the maximum light intensity of 75% can be found to obtain the working point wavelength of the FP cavity acoustic sensor, such as Figure 6 As shown in the circle; (3) Calculate the periodic mean of the wavelength at the working point through multiple peaks; (4) The wavelength value configured on the scanning light source 21 is calculated based on the wavelength period of the working point, so that the system works at the working point Q.

[0040] The working point control of this embodiment is specifically implemented in the software with two schemes: (1) the output light intensity corresponding to the known Q point ; (2) The output light intensity corresponding to the Q point is unknown , can only be obtained by calculating 75% of the maximum light intensity. The difference between the two is whether there is a working point Q module. In the specific implementation of the software, the light source working wavelength module, mean value calculation module, maximum point module, working wavelength period module, working point Q module and working wavelength determination module are set.

[0041] Light source working wavelength module: used to indicate the wavelength position of the current scanning light source. Its input is the two level pins of the light source, and the wavelength is determined by counting the number of pulses. Average module: The input is the light intensity of the scanning light source after being reflected by the probe. In this system, the sampling rate is much greater than the scanning frequency of the light source, so an average module is used to reduce the interference of noise; Maximum point module: The calculated mean is obtained through a maximum point module Figure 5 Each peak point in the system can be used to determine the working wavelength period of the system; Working wavelength cycle module: Since there are multiple peak points, multiple peak cycles will be calculated. There will be a certain error in each cycle. To reduce the error, this module will take the average of each peak cycle as the output, which is the working wavelength cycle output of the current system scanning cycle; Working point Q module: used to calculate the light intensity of the emission wavelength after being reflected by the probe when the system works at point Q. The value is theoretically 75% of the maximum value. Figure 5 It can be seen that multiple maximum points will be scanned, and 75% of each maximum value will have errors. To reduce the error, the module will take the average of the light intensity values ​​calculated from each peak as the output, as the light intensity value corresponding to the working wavelength output in the current system scanning cycle, and output the last wavelength corresponding to the light intensity value as the working wavelength; Working wavelength determination module: With the working wavelength and working wavelength cycle, the working wavelength cycle can be accumulated until the wavelength value reaches the scanning wavelength range of the tunable light source 22, and the wavelength value is output, and the lower-level module configures the value to the scanning light source 21.

[0042] In this embodiment, the high-frequency optical microphone is based on the optical interference intensity demodulation-operating point control method. This demodulation method converts the change of interference spectrum intensity into a voltage signal for demodulation based on the spectral sideband filtering technology, and has the characteristics of fast demodulation speed, good real-time dynamics, simple system, high sensitivity, etc., and is widely used in the demodulation of high-sensitivity and wide-bandwidth signals.

[0043] When the operating wavelength is at the orthogonal point (Q point) where the slope of the interference spectrum is the largest, FPI exhibits linear response and maximum sensitivity. If the operating wavelength drifts to the peak of the interference spectrum or decreases, the sensitivity and linearity of FPI deteriorate significantly. During the signal demodulation process, the operating wavelength of the input light should always be controlled at the Q point to achieve high sensitivity and linear response of the system.

[0044] It should be noted that the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0045] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0046] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0047] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application.

Claims

1. A high frequency microphone system, characterized in that: It comprises a sensing probe (1), a fiber interferometer (2), a photoelectric conversion module (3), an interference signal demodulation module (4), a light source compensation module (5), and a synchronization module (6); the fiber interferometer (2) comprises a scanning light source (21), a tunable light source (22), a beam combiner (23), a circulator (24), and a wavelength division multiplexer (25); The high-frequency microphone system includes a sensing optical path and a feedback optical path; The sensing optical path is as follows: a tunable light source (22) emits a first light beam, the first light beam passes through a circulator (24) and reaches a sensing probe (1), the sensing probe (1) is used to modulate a collected acoustic wave signal onto the first light beam to obtain a modulated signal, the modulated signal passes through the circulator (24) and reaches a photoelectric conversion module (3) to be converted into a first electrical signal, the first electrical signal is input into an interference signal demodulation module (4) to demodulate an acoustic wave signal, the demodulated acoustic wave signal is input into a synchronization module (6) to obtain a target acoustic signal; The feedback optical path is as follows: the scanning light source (21) emits a second light beam, the second light beam passes through a circulator (24) and reaches the sensor probe (1), the second light beam interferes with the sensor probe (1) and then passes through the circulator (24) to reach the photoelectric conversion module (3) to be converted into a second electrical signal, the second electrical signal is input into the light source compensation module (5) to generate a compensation light beam, and the compensation light beam is emitted into the optical fiber interferometer (2) to adjust the working point of the high-frequency microphone system.

2. The system according to claim 1, characterized in that The sensing probe (1) is a high-reflectivity FP cavity, comprising two high-reflectivity mirrors.

3. The system according to claim 2, characterized in that The fiber optic interferometer (2) is a fiber optic FP interferometer.

4. The system according to claim 3, characterized in that The sensor probe (1) is used to modulate the collected sound wave signal onto a first light beam to obtain a first modulated signal, comprising: The sensing probe (1) acquires an external sound wave signal, which causes the refractive index of air in the high-reflectivity FP cavity to change, thereby causing the phase of the first light beam to change, and then interferes in the sensing probe (1) to form a first modulated signal.

5. The system according to claim 4, characterized in that The photoelectric conversion module includes a first photodetector and a second photodetector.

6. The system according to claim 5, characterized in that The first electrical signal and the second electrical signal are both analog electrical signals.

7. A method for controlling an operating point of a high-frequency microphone system according to any one of claims 1 to 6, comprising the following steps: S1: controlling the scanning light source (21) to perform wavelength scanning within a frequency band, and collecting the output light intensity of the light beam passing through the sensor probe (1); S2: obtaining the actual working point wavelength of the sensing probe (1) based on the corresponding relationship between the scanning wavelength of the scanning light source (21) and the output light intensity; S3: Based on the actual working point wavelength and the initial calibration working point wavelength, obtaining the wavelength deviation of the sensor working point; S4: configuring the operating wavelength of the tunable light source (22) based on the wavelength deviation, so that the high-frequency microphone system is always at the operating point.

8. The method according to claim 7, characterized in that Step S2 includes: S21: based on the corresponding relationship between the scanning wavelength of the scanning light source (21) and the output light intensity, drawing a reflection spectrum of the high reflectivity FP cavity; S22: determine all the maximum points of the reflection spectrum of the high reflectivity FP cavity; S23: Obtain the wavelengths corresponding to all maximum points at 75% output light intensity, and obtain multiple intermediate wavelengths; S24: Using the average value of the multiple intermediate wavelengths as the actual working point wavelength of the sensing probe (1).

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