技术领域Technical field
本公开涉及声学测量和光学领域，具体地说，涉及一种利用光学元件探测水下极端环境下微弱声波信号的方法和装置。The present disclosure relates to the fields of acoustic measurement and optics, and specifically, to a method and device for detecting weak acoustic signals in extreme underwater environments using optical elements.
背景技术Background technique
水下声波信号探测广泛应用于水中通信、探洲、目标定位、跟踪、海洋环境监测等领域。现有技术中有压电水听器，它是利用压电陶瓷作为换能材料，压电陶瓷管之间用绝缘垫圈粘结定位。陶瓷管在声压作用下变形，借助其压电效应，从而产生电信号输出。但是这种水听器存在灵敏度低、固有频率高、动态范围小等缺点。专利2016103163457公开了另一类用于声波检测的高灵敏度水听器，包括声电换能模块，响应所接收到的声信号并将其转换为电信号后予以输出，第一输出匹配模块，以及直流电源模块等。虽然，这种水听器能够在谐振状态工作，可实现特定频段声波信号的高灵敏度检测，在一定程度上克服了现有非谐振型压电水听器灵敏度低的缺点，以及弥补了现有非谐振型压电水听器换能元件周围设置共振腔结构只能检测低频段的声波信号的不足，但是仍旧无法适用于恶劣环境中，如高温、高压和强电磁干扰的环境，以及不能实现对水下微弱声波信号的检测，并且价格十分昂贵，前期准备时间长、采集声音信号方法繁琐。Underwater acoustic signal detection is widely used in underwater communications, island exploration, target positioning, tracking, marine environment monitoring and other fields. There is a piezoelectric hydrophone in the prior art, which uses piezoelectric ceramics as the energy conversion material, and the piezoelectric ceramic tubes are bonded and positioned with insulating washers. The ceramic tube deforms under the action of sound pressure and uses its piezoelectric effect to produce an electrical signal output. However, this hydrophone has shortcomings such as low sensitivity, high natural frequency, and small dynamic range. Patent 2016103163457 discloses another type of high-sensitivity hydrophone for acoustic wave detection, including an acoustic-electric transducer module that responds to the received acoustic signal and converts it into an electrical signal and then outputs it, a first output matching module, and DC power module, etc. Although this kind of hydrophone can work in a resonant state, it can achieve high-sensitivity detection of acoustic signals in a specific frequency band, overcome the shortcomings of low sensitivity of existing non-resonant piezoelectric hydrophones to a certain extent, and make up for the existing low sensitivity of non-resonant piezoelectric hydrophones. The resonant cavity structure set up around the transducing element of the non-resonant piezoelectric hydrophone can only detect low-frequency acoustic signals, but it is still not suitable for harsh environments, such as high temperature, high pressure and strong electromagnetic interference environments, and cannot be implemented The detection of weak underwater sound wave signals is very expensive, requires long preparation time, and the method of collecting sound signals is cumbersome.
此外，现有技术中也有学者提出了基于干涉型光纤水听器测量水下声音信号，例如现有的基于光纤声学的传感技术，是通过平直的光纤端面与一个具有高杨氏模量的隔膜构成的外部法布里-珀罗干涉仪结构进行声音采集的一项技术。其工作原理是利用声波信号振动隔膜从而传递声音，当声波作用于隔膜上时，隔膜会发生形变，所以隔膜的选择对传感装置的灵敏度好坏至关重要。但是，这种基于隔膜的声学传感结构均存在一定的局限性，因为其受到相关结构的力学性能的影响。例如，他们实现高灵敏度需要较大的元件尺寸和谐振材料，从而导致较差的频率响应特性；因此现有的声学传感结构需要一种新型的传感模式克服现有的声学传感技术的局限性并且可以适用于测量微弱声音信号的新的测量方法。In addition, some scholars in the existing technology have proposed measuring underwater sound signals based on interference type fiber optic hydrophones. For example, the existing fiber optic acoustics-based sensing technology uses a straight fiber end face and a high Young's modulus A technique for sound collection using an external Fabry-Perot interferometer structure consisting of a diaphragm. Its working principle is to use sound wave signals to vibrate the diaphragm to transmit sound. When sound waves act on the diaphragm, the diaphragm will deform, so the selection of the diaphragm is crucial to the sensitivity of the sensing device. However, this diaphragm-based acoustic sensing structure has certain limitations because it is affected by the mechanical properties of the related structure. For example, they require larger component sizes and resonant materials to achieve high sensitivity, resulting in poor frequency response characteristics; therefore, the existing acoustic sensing structure requires a new sensing mode to overcome the limitations of existing acoustic sensing technology. limitations and can be applied to new measurement methods for measuring weak sound signals.
发明内容Contents of the invention
本公开提出了一种探听水下微弱声波的方法、装置以及制作方法，能够解决背景技术中指出的现有技术问题。The present disclosure proposes a method, device and production method for detecting weak underwater sound waves, which can solve the existing technical problems pointed out in the background art.
基础方案1：Basic plan 1:
一种探听水下微弱声波的方法，所述方法包括：A method for detecting weak underwater sound waves, the method includes:
利用光纤光镊技术对悬浮粒子进行稳定捕获，通过皮牛量级的光力将粒子捕获在所形成的光阱的内部，携带动量和能量的声波信号在流体介质中传播，引起在光阱中的粒子产生振动，所述粒子在与声波的接触面上发生动量交换，粒子将收集到的声波信号通过光束的干涉效应传输到光纤侧形成声波数据，对所获得的声波数据进行解调处理得到原始声波信号。Fiber optic tweezers technology is used to stably capture suspended particles. The particles are captured inside the formed optical trap through the optical force of piconewton level. The acoustic wave signal carrying momentum and energy propagates in the fluid medium, causing the particles to move in the optical trap. The particles vibrate, and the particles exchange momentum on the contact surface with the sound wave. The particles transmit the collected sound wave signal to the optical fiber side through the interference effect of the light beam to form sound wave data. The obtained sound wave data is demodulated to obtain Original acoustic signal.
本方法采用的光纤光镊系统通过光纤尖端的梯度力和散射力所构成的合力实现对尖端粒子的操纵，对于具有抛物面或凸面的锥形光纤，光将形成高度聚焦的激光束，形成三维势阱来捕获、操纵和控制微小粒子。光在光纤尖端附近高度聚焦，实现将粒子稳定捕获在光纤尖端形成的光阱中心位置。一般被捕获在光阱中的粒子受到的光力处于皮牛量级，基于此种特性，在光阱中的粒子具有对外部环境变化十分敏感的特性。The fiber optic tweezers system used in this method achieves the manipulation of tip particles through the combined force of the gradient force and scattering force at the fiber tip. For tapered fibers with paraboloids or convex surfaces, the light will form a highly focused laser beam, forming a three-dimensional potential. Traps to capture, manipulate and control tiny particles. The light is highly focused near the fiber tip, stably capturing the particles in the center of the light trap formed at the fiber tip. Generally, the light force received by the particles trapped in the light trap is on the order of piconaws. Based on this characteristic, the particles in the light trap are very sensitive to changes in the external environment.
本公开还有另外两个应用方面：There are two further application aspects of this disclosure:
应用的第一个方面，即一种用于实施前述方法的装置，包括一个基于光纤光镊技术的粒子探针水听器，其特征在于所述水听器包括光源模块、声音采集模块、光电探测模块、数据采集模块、数据处理模块以及导光单元；The first aspect of the application, that is, a device for implementing the aforementioned method, includes a particle probe hydrophone based on fiber optic tweezers technology, characterized in that the hydrophone includes a light source module, a sound collection module, a photoelectric Detection module, data acquisition module, data processing module and light guide unit;
所述光源模块包括一个能够发射出固定波长单色光的激光器；所述激光器用于发射捕获激光；The light source module includes a laser capable of emitting fixed wavelength monochromatic light; the laser is used to emit capture laser;
所述声音采集模块用于采集声压和振动信号；The sound collection module is used to collect sound pressure and vibration signals;
所述光电探测模块用于将光信号转换为电信号；The photoelectric detection module is used to convert optical signals into electrical signals;
所述数据采集模块用于对光电探测模块输出的电信号进行数据采集；The data acquisition module is used to collect data from the electrical signals output by the photoelectric detection module;
所述数据处理模块用于对数据采集模块采集到的电信号进行后续处理；The data processing module is used for subsequent processing of the electrical signals collected by the data acquisition module;
所述导光单元采用光纤耦合器，按照如下模式分别同声音采集模块、光源模块和光电探测模块相连接：The light guide unit uses an optical fiber coupler and is connected to the sound collection module, light source module and photoelectric detection module according to the following modes:
所述光源模块中激光器发射的固定波长的单色光经过导光单元的第一端口进入导光单元中，从导光单元的第二端口连接拉制好的锥形光纤光镊；The fixed-wavelength monochromatic light emitted by the laser in the light source module enters the light guide unit through the first port of the light guide unit, and the drawn tapered optical fiber tweezers are connected from the second port of the light guide unit;
在光纤尖端发射出光束一部分进入声音采集模块内进行声压、振动检测，入射光束经过粒子内表面的反射后，携带声音信息的光信号重新射入光纤端面，再从导光单元的第二端口进入；A part of the light beam is emitted from the tip of the optical fiber and enters the sound collection module for sound pressure and vibration detection. After the incident light beam is reflected by the inner surface of the particle, the optical signal carrying the sound information is re-injected into the end face of the optical fiber, and then passes through the second port of the light guide unit. Enter;
另一部分光束经光纤端面反射，两束相干光在导光单元内发生干涉合成为单束光，再从导光单元的第三端口射出进入光电探测模块中将光信号转换为电信号，并由数据采集模块接收然后传输给数据处理模块对信号进行滤波处理和声音还原处理。Another part of the light beam is reflected by the end face of the optical fiber. The two coherent beams of light interfere in the light guide unit and are synthesized into a single beam of light. The light beam is then emitted from the third port of the light guide unit and enters the photoelectric detection module to convert the optical signal into an electrical signal. The data acquisition module receives and then transmits it to the data processing module for filtering and sound restoration processing of the signal.
前述水听器是通过基于光纤光镊技术的粒子探针实现水下声波的探听，基本原理是：The aforementioned hydrophone uses a particle probe based on fiber optic tweezers technology to detect underwater sound waves. The basic principle is:
锥形光纤光镊捕获二氧化硅微粒，二氧化硅微粒被稳定捕获在光纤光阱的中心，将微粒束缚在光阱中心的力属于皮牛量级。当外界微弱的声波信号传递到微球表面时，微球在光阱中发生微小尺度的振动，通过微粒的振动将声波信号转化为光信号的变化进而传递到光纤端，然后携带声波信息的光信号经过光电探测器后转换为电信号，通过对电信号的采集和处理，从而实现了对微弱声波信号的探测。其中，在光纤光镊尖端的出射光照射到微球表面时,该出射光可视为高度聚焦光束，一部分光在光纤尖端端面实现反射，另一部分光进入微球内部，经过微球的微尺度振动，两束光之间产生光程差，在光纤尖端处发生干涉现象，从而将携带声波信息的光信号传递到光纤侧所连接的光电探测器处，实现声波信号的解调与复现。The tapered optical fiber optical tweezers capture the silica particles, and the silica particles are stably captured in the center of the optical fiber optical trap. The force binding the particles to the center of the optical trap is on the order of a skin-newton. When a weak acoustic signal from the outside is transmitted to the surface of the microsphere, the microsphere vibrates at a small scale in the optical trap. Through the vibration of the particle, the acoustic signal is converted into a change in the optical signal and then transmitted to the optical fiber end, and then the light carrying the acoustic information is The signal is converted into an electrical signal after passing through the photodetector. Through the collection and processing of the electrical signal, the detection of weak acoustic signals is achieved. Among them, when the emitted light from the tip of the optical fiber tweezers irradiates the surface of the microsphere, the emitted light can be regarded as a highly focused beam. Part of the light is reflected at the end face of the fiber tip, and the other part of the light enters the interior of the microsphere and passes through the microscale of the microsphere. Vibration causes an optical path difference between the two beams of light, and interference occurs at the tip of the optical fiber, thereby transmitting the optical signal carrying the acoustic wave information to the photodetector connected to the optical fiber side to achieve demodulation and reproduction of the acoustic wave signal.
优选地，所述数据处理模块中包含算法显示模块，用于根据电压信号计算微粒测量声波信号和输出电压之间的关系，同时实时计算不同频率下的频域信号。Preferably, the data processing module includes an algorithm display module for calculating the relationship between the particle measurement acoustic wave signal and the output voltage based on the voltage signal, and at the same time calculating frequency domain signals at different frequencies in real time.
以及，所述声音采集模块包括：锥形光纤光镊和二氧化硅粒子；所述二氧化硅粒子用于进行声音信号传感，直径为3μm，位于光纤光镊前端所形成的光阱处，锥形光纤尖端与微球内表面构成一个F-P干涉腔。And, the sound collection module includes: tapered optical fiber optical tweezers and silica particles; the silica particles are used for sound signal sensing, have a diameter of 3 μm, and are located at the light trap formed by the front end of the optical fiber tweezers, The tapered optical fiber tip and the inner surface of the microsphere form an F-P interference cavity.
所述锥形光纤光镊，连接于所述导光单元光纤耦合器第三端口，所述装置置于水环境中；The tapered optical fiber optical tweezers are connected to the third port of the optical fiber coupler of the light guide unit, and the device is placed in a water environment;
所述锥形光纤光镊的前端有光阱区域，所述二氧化硅粒子被所述锥形光纤光镊稳定捕获后位于所述光阱区域内。There is a light trap area at the front end of the tapered fiber optic tweezers, and the silica particles are stably captured by the tapered fiber optic tweezers and are located in the light trap area.
进一步地，所述导光单元为2×2型光纤耦合器，分光比为10:90；所述光电探测模块为InGaAs光电二极管；所述光源模块采用的固定波长为980nm，功率范围设置在1-20mW之间。Further, the light guide unit is a 2×2 optical fiber coupler with a light splitting ratio of 10:90; the photoelectric detection module is an InGaAs photodiode; the fixed wavelength used by the light source module is 980nm, and the power range is set at 1 -20mW.
应用的第二个方面，即一种用于制作前述装置中锥形光纤光镊的方法，其独特之处在于，所述锥形光纤光镊通过熔融拉锥法制备，并在末端形成具有渐变的锥形结构，按照如下具体步骤进行：The second aspect of the application is a method for making tapered optical fiber optical tweezers in the aforementioned device. The unique feature is that the tapered optical fiber optical tweezers are prepared by a fusion tapering method and are formed with a gradient at the end. For the tapered structure, follow the following specific steps:
第一步，将单模光纤分别去掉缓冲层和聚合物涂覆层，并且套上毛细玻璃管；In the first step, the buffer layer and polymer coating layer of the single-mode optical fiber are removed respectively, and the capillary glass tube is put on;
第二步，将经由第一步去除缓冲层和聚合物涂覆层后的光纤置于氢氧火焰加热至光纤熔点后沿光轴方向进行拉伸；In the second step, the optical fiber after removing the buffer layer and polymer coating layer in the first step is heated to a hydrogen-oxygen flame to the melting point of the optical fiber and then stretched along the optical axis direction;
第三步，将经由第二步处理后裸露的单模光纤熔融的部分拉细，从而在末端形成渐变的锥形光纤结构即光纤光镊。In the third step, the molten part of the exposed single-mode optical fiber processed in the second step is thinned, thereby forming a tapered optical fiber structure at the end, that is, optical fiber tweezers.
优选地，所述第二步中对单模光纤的初始拉伸速度范围在0.3～0.46mm/s之间；最佳对单模光纤的初始拉伸速度为0.4mm/s。Preferably, the initial stretching speed of the single-mode optical fiber in the second step ranges from 0.3 to 0.46 mm/s; the optimal initial stretching speed of the single-mode optical fiber is 0.4 mm/s.
所述第二步中光纤直径首先从125μm在30-34μm范围内减至5μm，再从3-4μm范围内从5μm减小至1.5μm，此时将拉伸速度提高为1.6mm/s，光纤光镊在末端形成特定的锥形形状。In the second step, the optical fiber diameter is first reduced from 125 μm to 5 μm in the range of 30-34 μm, and then reduced from 5 μm to 1.5 μm in the range of 3-4 μm. At this time, the stretching speed is increased to 1.6 mm/s, and the optical fiber Optical tweezers form a specific tapered shape at the end.
本说明书一个或多个实施例采用的上述至少一个技术方案能够达到以下有益效果：At least one of the above technical solutions adopted in one or more embodiments of this specification can achieve the following beneficial effects:
首先，本公开给出的技术方案应用了基于光纤光镊捕获微球测量微弱声波信号的技术，利用光纤光镊原理设计了一种基于光纤光镊技术的粒子探针实现水下声波的探听装置。该装置采用在水中传递的微小声波信号引起微粒的微尺度振动，通过微粒的振动将声波信号转化为光信号的变化进而传递到光纤端，然后携带声波信息的光信号经过光电探测器后转换为电信号，通过对电信号的采集和处理，实现了对微弱声波信号的探测。与其他的水听器不同，声波采集模块不含有二维材质，水下压强的大尺度变化对该水听器的性能影响忽略不计，并且可以应用于强电磁干扰、高温、高压和强腐蚀等极端环境下对声波信号实现高灵敏度的探测。同时，该技术方案可以实现实时捕获待测信号，对于一些需要高精度、高实时性的应用场景具有很高的实用价值，例如医学、机械工程、航空等领域。First of all, the technical solution given in this disclosure applies the technology of capturing microspheres to measure weak acoustic signals based on optical fiber optical tweezers, and uses the principle of optical fiber optical tweezers to design a particle probe based on optical fiber optical tweezers technology to realize an underwater sound wave listening device. . The device uses tiny acoustic signals transmitted in water to cause microscale vibrations of particles. Through the vibration of the particles, the acoustic signals are converted into changes in optical signals and then transmitted to the optical fiber end. Then the optical signals carrying the acoustic information are converted into Electrical signals, through the collection and processing of electrical signals, detect weak acoustic signals. Unlike other hydrophones, the sound wave acquisition module does not contain two-dimensional materials. Large-scale changes in underwater pressure have a negligible impact on the performance of the hydrophone. It can be applied to strong electromagnetic interference, high temperature, high pressure, strong corrosion, etc. Achieve high-sensitivity detection of acoustic signals in extreme environments. At the same time, this technical solution can capture the signal to be measured in real time, and has high practical value for some application scenarios that require high precision and high real-time performance, such as medicine, mechanical engineering, aviation and other fields.
其次，本公开给出的技术方案将悬浮微米级微粒利用光镊技术实现单光束力阱稳定捕获，并利用其在光阱中受到微弱声波信号所产生的微尺度振动进而能够结合其他领域的现有技术实现在水下环境中声波信号的高时空探测，数据实时采集，处理并显示各项声音指标参数。Secondly, the technical solution given by this disclosure uses optical tweezers technology to achieve stable capture of suspended micron-sized particles in a single-beam force trap, and uses the micro-scale vibrations generated by weak acoustic signals in the optical trap to be combined with existing technologies in other fields. There is technology to achieve high spatial and temporal detection of acoustic signals in the underwater environment, real-time data collection, processing and display of various sound index parameters.
综上所述，通过本公开提出的技术方案能够实现频率为5Hz-20kHz范围内声波信号探测，具有高度灵敏度和信噪比，从而满足各种工况下的水下声音探测。To sum up, the technical solution proposed in this disclosure can realize the detection of acoustic signals in the frequency range of 5Hz-20kHz, with high sensitivity and signal-to-noise ratio, thereby satisfying underwater sound detection under various working conditions.
应当理解的是，以上的一般描述和后文的细节描述仅是示例性和解释性的，而非限制本公开。It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the disclosure.
根据下面参考附图对示例性实施例的详细说明，本公开的其它特征及方面将变得清楚。Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.
附图说明Description of the drawings
此处的附图被并入说明书中并构成本说明书的一部分，这些附图示出了符合本公开的实施例，并与说明书一起用于说明本公开的技术方案。The accompanying drawings herein are incorporated into and constitute a part of this specification. They illustrate embodiments consistent with the disclosure and, together with the description, serve to explain the technical solutions of the disclosure.
图1示出根据公开实施例的一种基于光纤光镊技术的粒子探针水听器的声波采集装置图。Figure 1 shows a diagram of an acoustic wave collection device of a particle probe hydrophone based on fiber optic tweezers technology according to disclosed embodiments.
图2示出根据公开实施例的一种基于光纤光镊技术的粒子探针水听器结构图。Figure 2 shows a structural diagram of a particle probe hydrophone based on fiber optic tweezers technology according to disclosed embodiments.
图3示出本公开具体实施例下光镊光力仿真图，其中图3(a)为光纤仿真示意图；图3(b)为沿光轴(x轴)方向光力分布图；图3(c)为在x＝0.12μm处沿(y轴)方向光力分布图。Figure 3 shows the optical force simulation diagram of optical tweezers under a specific embodiment of the present disclosure, wherein Figure 3(a) is a schematic diagram of optical fiber simulation; Figure 3(b) is a light force distribution diagram along the optical axis (x-axis); Figure 3( c) is the light force distribution diagram along the (y-axis) direction at x=0.12μm.
图4示出本公开具体实施例下的一种基于光纤光镊技术的粒子探针水听器光束干涉原理图。Figure 4 shows a principle diagram of beam interference of a particle probe hydrophone based on fiber optical tweezers technology under a specific embodiment of the present disclosure.
图5示出本公开具体实施例下的一种基于光纤光镊技术的粒子探针水听器实现水下声音信号探测的步骤图。Figure 5 shows a step diagram for realizing underwater sound signal detection using a particle probe hydrophone based on optical fiber optical tweezers technology under a specific embodiment of the present disclosure.
图6示出本公开具体实施例下实现了探测不同频率大小的声波信号的数据图。Figure 6 shows a data diagram for detecting acoustic wave signals of different frequencies under a specific embodiment of the present disclosure.
图7示出了本公开具体实施例下发明探测到的电压信号和施加在微粒上的声压幅值之间的关系图。FIG. 7 shows the relationship between the voltage signal detected by the invention and the amplitude of the sound pressure exerted on the particles under a specific embodiment of the present disclosure.
图中1-光源，2-导光单元，3-锥形光纤光镊，4-声音传感模块，5-光电探测模块，6-数据采集模块，7-数据处理模块，8-算法显示模块，9-锥形光纤；10-二氧化硅粒子；11-光镊前端光阱。In the figure, 1-light source, 2-light guide unit, 3-tapered optical fiber tweezers, 4-sound sensing module, 5-photoelectric detection module, 6-data acquisition module, 7-data processing module, 8-algorithm display module , 9-tapered optical fiber; 10-silica particles; 11-optical tweezers front-end light trap.
具体实施方式Detailed ways
以下将参考附图详细说明本公开的各种示例性实施例、特征和方面。附图中相同的附图标记表示功能相同或相似的元件。尽管在附图中示出了实施例的各种方面，但是除非特别指出，不必按比例绘制附图。Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numbers in the drawings identify functionally identical or similar elements. Although various aspects of the embodiments are illustrated in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.
另外，为了更好地说明本公开，在下文的具体实施方式中给出了众多的具体细节。本领域技术人员应当理解，没有某些具体细节，本公开同样可以实施。在一些实例中，对于本领域技术人员熟知的方法、手段、元件和电路未作详细描述，以便于凸显本公开的主旨。下面给出一个具体实施例，意图结合附图和实施例对本公开所给出的技术方案做进一步详细描述，需要指出的是，以下所述实施例旨在便于对本公开的理解，而对其不起任何限定作用。In addition, in order to better explain the present disclosure, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present disclosure may be practiced without certain specific details. In some instances, methods, means, components and circuits that are well known to those skilled in the art are not described in detail in order to emphasize the subject matter of the disclosure. A specific embodiment is given below, with the intention of further describing the technical solution provided by the present disclosure in detail with reference to the drawings and examples. It should be noted that the following embodiments are intended to facilitate the understanding of the present disclosure and are not intended to disqualify it. play any limiting role.
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。本申请中附图编号仅用于区分方案中的各个步骤，不用于限定各个步骤的执行顺序，具体执行顺序以说明书中描述为准。The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. The numbers in the drawings in this application are only used to distinguish each step in the solution, and are not used to limit the execution order of each step. The specific execution order shall be subject to the description in the specification.
本申请实施例提供的装置可以应用于强电磁干扰、高温、高压和强腐蚀等极端环境下对声波信号的高灵敏度的检测。The device provided by the embodiment of the present application can be used for highly sensitive detection of acoustic signals in extreme environments such as strong electromagnetic interference, high temperature, high pressure, and strong corrosion.
本公开下面的实施例提供一种基于光纤光镊技术的粒子探针实现水下声波的探听装置，该装置利用光纤光镊技术实现对微粒的三维捕获，微米级粒子在光阱中所受到的皮牛级光力的作用，粒子对外部环境的声波信号十分敏感，致使粒子在光阱中产生微尺度振动，振动改变光程差发生干涉效应，后续利用解调方式，实现声波信号的复现：The following embodiments of the present disclosure provide a device for detecting underwater acoustic waves using a particle probe based on fiber optic tweezers technology. The device uses fiber optic tweezers technology to achieve three-dimensional capture of particles. The micron-sized particles in the optical trap are subjected to Due to the action of bovine-level light force, the particles are very sensitive to the acoustic wave signals of the external environment, causing the particles to produce micro-scale vibrations in the optical trap. The vibrations change the optical path difference and cause an interference effect. Subsequent demodulation methods are used to realize the recurrence of the acoustic wave signals. :
如图1所示的采用一种基于光纤光镊技术的粒子探针水听器：能够发出固定波长的激光器；作为光传输介质以及实现分光功能的导光单元；感应声波振动信号的声音传感模块是由一根锥形光纤光镊和光阱中的二氧化硅粒子组成；将光信号转换为电信号的光电探测模块；实现信号采集功能的数据采集模块；对采集到的信号进行处理的数据处理模块；激光器发射的单色光从导光单元的端口Ⅰ进入导光单元中，从导光单元的端口II发射光束，通过锥形光纤光镊进入水听器声音采集模块内与二氧化硅粒子构成一个F-P腔进行声音振动传感，F-P干涉光从导光单元的端口II进入，再从导光单元的端口IV射出进入光电探测模块进行光信号转化为电信号。然后通过数据采集模块采集，并传输到数据处理模块通过软件实时显示时域信号，随后进入算法显示模块将时域信号转化为频域信号，通过代码实现声音还原。As shown in Figure 1, a particle probe hydrophone based on fiber optic tweezers technology is used: a laser capable of emitting a fixed wavelength; a light guide unit that serves as an optical transmission medium and realizes light splitting function; and a sound sensor that senses acoustic vibration signals. The module is composed of a tapered optical fiber optical tweezer and silica particles in the optical trap; a photoelectric detection module that converts optical signals into electrical signals; a data acquisition module that implements signal acquisition functions; and data processing for the collected signals. Processing module; the monochromatic light emitted by the laser enters the light guide unit from port I of the light guide unit, emits a beam from port II of the light guide unit, and enters the hydrophone sound collection module through the tapered optical fiber tweezers to interact with the silica The particles form an F-P cavity for sound vibration sensing. The F-P interference light enters from the port II of the light guide unit, and then exits from the port IV of the light guide unit and enters the photodetection module to convert the optical signal into an electrical signal. Then it is collected through the data acquisition module and transmitted to the data processing module to display the time domain signal in real time through the software. Then it enters the algorithm display module to convert the time domain signal into a frequency domain signal, and realizes sound restoration through code.
如图2所示水听器声音采集模块包括：用于接收声波信号的二氧化硅粒子、用于传输光和捕获粒子的锥形光纤光镊，光纤尖端与粒子内表面构成F-P腔。As shown in Figure 2, the hydrophone sound collection module includes: silica particles for receiving acoustic signals, and tapered optical fiber tweezers for transmitting light and capturing particles. The fiber tip and the inner surface of the particles form an F-P cavity.
本种基于光纤光镊技术的粒子探针水听器装置，使用光纤作为传输光的介质，二氧化硅粒子作为探测声波信号的换能器，光纤端面与粒子之间的传感区域≤λ/8，结构紧凑小巧，灵敏度高且适用范围广泛。本发明的目的在于使用新颖的光纤-粒子探针结构测量声波的结构，来提高水听器的测量精度与信号稳定性。This particle probe hydrophone device based on fiber optic tweezers technology uses optical fiber as the medium for transmitting light, and silica particles as transducers for detecting acoustic signals. The sensing area between the fiber end face and the particles is ≤λ/ 8. Compact structure, high sensitivity and wide application range. The purpose of the present invention is to use a novel optical fiber-particle probe structure to measure the structure of sound waves to improve the measurement accuracy and signal stability of the hydrophone.
对声波信号敏感的微粒是光纤水听器的重要组成部分之一，水听器通过在光阱中的粒子感知外界声压的变化。本例的水听器结构属于非本征型F-P干涉式光纤传感结构，光纤与粒子内表面构成F-P腔，因此只需要考虑粒子与光纤端面之间的距离，粒子受到光镊的光力作用稳定在光阱内部，为了实现粒子探测的高灵敏度，利用光镊施加的最小光力实现粒子的捕获。光镊所施加的光力的大小直接影响了传感器的性能，对水听器的设计制作非常重要。传感器的灵敏度很大程度上与光镊施加的光力有关。Particles that are sensitive to acoustic signals are one of the important components of fiber optic hydrophones. The hydrophone senses changes in external sound pressure through particles in the optical trap. The hydrophone structure in this example belongs to the extrinsic F-P interference fiber sensing structure. The fiber and the inner surface of the particle form an F-P cavity. Therefore, only the distance between the particle and the fiber end face needs to be considered. The particle is affected by the optical force of the optical tweezers. Stable inside the optical trap, in order to achieve high sensitivity in particle detection, the minimum optical force exerted by optical tweezers is used to capture the particles. The amount of light force exerted by optical tweezers directly affects the performance of the sensor, which is very important for the design and production of hydrophones. The sensitivity of the sensor is largely related to the optical force exerted by the optical tweezers.
光镊施加给粒子的光力可以表示为：The optical force exerted by optical tweezers on particles can be expressed as:
其中，在粒子周围的封闭表面S上积分，n时表面法向量。<TM>是与时间无关的麦克斯韦应力张量，可以按照以下的方式计算：Among them, integrating on the closed surface S around the particle, n is the surface normal vector. <TM > is the time-independent Maxwell stress tensor, which can be calculated as follows:
其中，EE*和HH*表示电磁场的外积；ε是电导率；μ是磁导率；上标“*”表示共轭；I表示各向同性张量。Among them, EE* and HH* represent the outer product of the electromagnetic field; ε is the electrical conductivity; μ is the magnetic permeability; the superscript "*" represents conjugation; I represents the isotropic tensor.
通过仿真模拟，仿真结果如图3所示，当粒子距离光纤尖端之间的距离为0.12μm时，此时的捕获力大小为177.2pN。Through simulation, the simulation results are shown in Figure 3. When the distance between the particle and the fiber tip is 0.12μm, the capture force at this time is 177.2pN.
光纤端面与粒子内表面构成一个简单的F-P腔，近似成一个双光束干涉。激光从光纤发射，同时大约4％的光束从光纤端面反射回来，其余光束则传输到微球表面，微球内表面反射的光束携带声音信号重新进入光纤中，这两束光束在光纤端面处发生干涉，光束干涉原理如图4所示。The fiber end face and the inner surface of the particle form a simple F-P cavity, which is approximately a double-beam interference. The laser is emitted from the optical fiber. At the same time, about 4% of the beam is reflected back from the end face of the optical fiber. The remaining beam is transmitted to the surface of the microsphere. The beam reflected on the inner surface of the microsphere carries the sound signal back into the optical fiber. These two beams occur at the end face of the optical fiber. Interference, the principle of beam interference is shown in Figure 4.
假设入射光功率设为Pi，光纤端面上的反射回的光为Po1，而入射到微球端面的透射光的反射光为Po2。两束反射光在光纤端面上相遇法布里-珀罗干涉效应。Assume that the incident light power is set to Pi , the light reflected back on the fiber end face is Po1 , and the reflected light of the transmitted light incident on the microsphere end face is Po2 . The two reflected lights encounter the Fabry-Perot interference effect on the fiber end face.
反射光功率为The reflected light power is
其中Pi和Pr分别为入射光功率和反射光功率。R1和R2是光纤折射率和二氧化硅粒子的折射率。表示从光纤端面到微球端面的总相移，可以表示为WherePi and Pr are the incident light power and reflected light power respectively. R1 and R2 are the refractive index of the fiber and the refractive index of the silica particles. Represents the total phase shift from the fiber end face to the microsphere end face, which can be expressed as
式中，n为折射率(腔内介质为水，n＝1.33)，L(t)为法布里-珀罗腔长度的总变化，λ为激光波长。In the formula, n is the refractive index (the cavity medium is water, n=1.33), L(t) is the total change in the length of the Fabry-Perot cavity, and λ is the laser wavelength.
L(t)＝L0+ΔL(t)＝L0+(λΔφL(t))/4π (3)L(t)＝L0 +ΔL(t)＝L0 +(λΔφL(t))/4π (3)
经由光电探测器探测所得的输出电压为:The output voltage detected by the photodetector is:
其中代表光电探测器的增益，S表示水听器的灵敏度，ΔL表示声波信息所引起F-P空腔长度的变化。in represents the gain of the photodetector, S represents the sensitivity of the hydrophone, and ΔL represents the change in FP cavity length caused by acoustic wave information.
当外腔长度L的变化被限制在一个较小的范围内(≤λ/8)此时的输出电压即此时的输出电压与外部的声波信号呈现良好的线性关系。When the change in the length L of the external cavity is limited to a small range (≤λ/8), the output voltage at this time That is, the output voltage at this time has a good linear relationship with the external acoustic signal.
本公开实施例提供了一种基于光纤光镊技术的粒子探针水听器装置，该装置可以应用于水下声学检测，图5示出根据本公开实施例的基于光纤光镊技术的粒子探针水听器系统流程图。Embodiments of the present disclosure provide a particle probe hydrophone device based on fiber optic tweezers technology, which can be applied to underwater acoustic detection. Figure 5 shows a particle probe hydrophone device based on fiber optic tweezers technology according to an embodiment of the disclosure. Needle hydrophone system flow diagram.
S100：基于激光器发射的第一光信号，在经过导光单元分光得到第二光信号，经过光纤尖端和粒子内表面的反射得到第三光信号和第四光信号，第三光信号和第四光信号干涉合成第五光信号。S100: Based on the first optical signal emitted by the laser, the second optical signal is obtained by splitting the light through the light guide unit, and the third optical signal and the fourth optical signal are obtained through the reflection of the fiber tip and the inner surface of the particle, and the third optical signal and the fourth optical signal are obtained. The optical signals are interfered to synthesize a fifth optical signal.
S200：对第五光信号进行光电转换，得到第一电信号，数据采集模块采集第一电信号并将其转化为数字信号传输到数字处理模块，可以实时显示声音的时域信号。S200: Perform photoelectric conversion on the fifth optical signal to obtain the first electrical signal. The data acquisition module collects the first electrical signal and converts it into a digital signal and transmits it to the digital processing module, which can display the time domain signal of the sound in real time.
S300：第一电信号通过电压来反映粒子的振动频率以及幅值，基于F-P干涉原理和强度解调原理，通过代码实现声音信号的还原。S300: The first electrical signal reflects the vibration frequency and amplitude of the particles through voltage. Based on the F-P interference principle and the intensity demodulation principle, the sound signal is restored through the code.
具体实现时，所述数据处理模块中的算法显示模块，用于根据电压信号计算微粒测量声波信号和输出电压之间的关系，同时实时计算不同频率下的频域信号，下面给出声音信号解调算法，所述方法包括：During specific implementation, the algorithm display module in the data processing module is used to calculate the relationship between the particle measurement acoustic wave signal and the output voltage based on the voltage signal, and at the same time calculate the frequency domain signals at different frequencies in real time. The sound signal solution is given below Adjustment method, the method includes:
S1.干涉光信号数学模型：S1. Mathematical model of interference light signal:
具体的，在本实施例中，光干涉信号数学模型表示为：Specifically, in this embodiment, the mathematical model of the optical interference signal is expressed as:
式中：IoIr分别为入射光的入射光强以及反射光强度，R1R2分别为光纤端面折射率与微球的折射，表示从光纤端面到微球端面的总相移，n为折射率(腔内介质为水，n＝1.33)，λ为激光波长。In the formula: Io Ir are the incident light intensity and reflected light intensity of the incident light respectively, R1 R2 are the refractive index of the fiber end face and the refraction of the microsphere, respectively. Represents the total phase shift from the fiber end face to the microsphere end face, n is the refractive index (the medium in the cavity is water, n=1.33), and λ is the laser wavelength.
令干涉条纹对比度则(3)转化为：Let the interference fringe contrast Then (3) is transformed into:
其中L0为光纤尖端与微粒之间的初始距离，ΔL为当粒子受到外界声波信号的影响，与光纤端面之间距离变化。 Among them, L0 is the initial distance between the fiber tip and the particle, and ΔL is the change in distance between the particle and the fiber end face when it is affected by external acoustic wave signals.
根据水中传播的微弱声波信号使得光纤尖端与粒子之间的距离L被限制在λ/8范围内，此时反射光Ir与在光阱中粒子的振动位移可以近似表示为：According to the weak acoustic signal propagating in the water, the distance L between the fiber tip and the particle is limited to the range of λ/8. At this time, the reflected light Ir and the vibration displacement of the particle in the optical trap can be approximately expressed as:
其中/>代表比例系数。 Among them/> Represents the proportional coefficient.
S2.对光干涉信号进行快速傅里叶变换S2. Perform fast Fourier transform on the optical interference signal
对接收到的光信号按照下式，进行快速傅里叶变换：Perform fast Fourier transform on the received optical signal according to the following formula:
S3:根据得到的频域信号，进行滤波处理，利用FIR滤波器S3: Perform filtering processing based on the obtained frequency domain signal, using FIR filter
FIR滤波器的冲击响应是有限长的，数字M阶FIR滤波器可以表述为：Impulse response of FIR filter is finite length, the digital M-order FIR filter can be expressed as:
其系统函数为：Its system function is:
S4：根据滤波处理好的信号，进行强度解调：S4: Perform intensity demodulation based on the filtered signal:
根据(5)式可知，水听器输出的光强度是腔长L的单变量函数，如以水听器腔长L为横坐标，滤波后的干涉信号为纵坐标，将(5)化简为：According to equation (5), it can be seen that the light intensity output by the hydrophone is a single-variable function of the cavity length L. For example, taking the hydrophone cavity length L as the abscissa and the filtered interference signal as the ordinate, simplify (5) for:
可知输出光信号与声波信号之间为正比例关系，随后得到解调出的声波信号。It can be seen that there is a direct proportional relationship between the output optical signal and the acoustic wave signal, and then the demodulated acoustic wave signal is obtained.
图6示出本发明采集到的不同频率大小的声波信号，分别为20Hz、400Hz、1000Hz的时域波形图以及频域。Figure 6 shows the acoustic wave signals of different frequencies collected by the present invention, which are the time domain waveform diagrams and frequency domain of 20Hz, 400Hz, and 1000Hz respectively.
图7示出本发明探测到的电压信号和施加在微粒上的声压幅值之间的关系图。分析该图可知，探测到的电压幅值和施加在微粒上的声压幅值表现出良好的线性关系。Figure 7 shows the relationship between the voltage signal detected by the present invention and the amplitude of the sound pressure exerted on the particles. Analysis of this figure shows that the detected voltage amplitude and the sound pressure amplitude exerted on the particles show a good linear relationship.
综上所述，本公开实施例的技术方案实现了高灵敏度、无接触的实时测量微弱声波信号。采用实时检测的方法，能够快速准确地还原声波信号，适用于对实时性要求较高的场景。通过利用光学的高灵敏度和精度，实现对更高精度、更复杂的声波信号的检测和还原。In summary, the technical solutions of the embodiments of the present disclosure enable high-sensitivity, contactless real-time measurement of weak acoustic signals. The real-time detection method can quickly and accurately restore the acoustic signal, which is suitable for scenarios with high real-time requirements. By utilizing the high sensitivity and precision of optics, higher-precision and more complex acoustic wave signals can be detected and restored.
以上已经描述了本公开的实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择，旨在最好地解释各实施例的原理、实际应用或对市场中的技术改进，或者使本技术领域的其它普通技术人员能理解本文披露的各实施例附图中的流程图和框图显示了根据本公开的多个实施例的系统、方法和计算机程序产品的可能实现的体系架构、功能和操作。在这点上，流程图或框图中的每个方框可以代表一个模块、程序段或指令的一部分，所述模块、程序段或指令的一部分包含一个或多个用于实现规定的逻辑功能的可执行指令。在有些作为替换的实现中，方框中所标注的功能也可以以不同于附图中所标注的顺序发生。例如，两个连续的方框实际上可以基本并行地执行，它们有时也可以按相反的顺序执行，这依所涉及的功能而定。也要注意的是，框图和/或流程图中的每个方框、以及框图和/或流程图中的方框的组合，可以用执行规定的功能或动作的专用的基于硬件的系统来实现，或者可以用专用硬件与计算机指令的组合来实现。The embodiments of the present disclosure have been described above. The above description is illustrative, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements in the market of each embodiment, or to enable other persons of ordinary skill in the art to understand the description of the embodiments disclosed herein. The flowcharts and block diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions that embody one or more elements for implementing the specified logical function(s). Executable instructions. In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two consecutive blocks may actually execute substantially in parallel, or they may sometimes execute in the reverse order, depending on the functionality involved. It will also be noted that each block of the block diagram and/or flowchart illustration, and combinations of blocks in the block diagram and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts. , or can be implemented using a combination of specialized hardware and computer instructions.
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| CN202311046735.3ACN117053914A (en) | 2023-08-19 | 2023-08-19 | Method and device for detecting underwater weak sound wave and manufacturing method |
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