阅读说明：本技术 一种基于超声波检测电压的光纤传感装置及实现方法 (Optical fiber sensing device based on ultrasonic detection voltage and implementation method ) 是由 冯月 恭艾娜 沈涛 陈姣姣 刘驰 王振家 王东兴 黄海 于 2020-11-19 设计创作，主要内容包括：本发明专利提供了一种基于超声波检测电压的光纤传感装置及实现方法,它包括ASE光源、光纤耦合器、传感单元、超声波转换装置、光电转换器、信号处理模块。本发明专利通过光纤进行传感,利用法珀腔原理,使ASE光源发出的光在法珀腔中产生干涉光谱,通过对干涉光谱的检测,测量电压,并且通过信号处理模块,实现数字输出,达到可以在计算机上显示的目的。本发明对超声波换能装置进行了结构设计,提高了效率,使超声波的频带加宽,实现了监测电压的目的。同时可以在主机上输出,实现了电压的实时监测。(The invention provides an optical fiber sensing device based on ultrasonic detection voltage and an implementation method thereof. The invention carries out sensing through the optical fiber, utilizes the principle of the Fabry-Perot cavity to enable the light emitted by the ASE light source to generate an interference spectrum in the Fabry-Perot cavity, measures the voltage through detecting the interference spectrum, and realizes digital output through the signal processing module, thereby achieving the purpose of displaying on a computer. The invention carries out structural design on the ultrasonic wave energy conversion device, improves the efficiency, widens the frequency band of ultrasonic waves and realizes the purpose of monitoring voltage. Meanwhile, the voltage can be output on the host, and the real-time monitoring of the voltage is realized.)

1. An optical fiber sensing device based on ultrasonic detection voltage and an implementation method are characterized in that: the optical fiber sensor comprises an ASE light source (1), an optical fiber coupler (2), a sensing unit (3), an ultrasonic conversion device (4), a photoelectric converter (5) and a signal processing module (6);

the sensing unit (3) comprises a single-mode fiber (3-1), a glass ferrule (3-2), a silicon ring (3-3), a quartz diaphragm (3-4), graphene (3-5) and a gold film (3-6), wherein:

an air Fabry-Perot cavity is formed by the inner surfaces of the single-mode optical fiber (3-1) and the silicon ring (3-3), the cavity length of the air Fabry-Perot cavity is about 26 mu m, the silicon ring (3-3) forms the silicon Fabry-Perot cavity, and the cavity length of the silicon Fabry-Perot cavity is 40 mu m of the height of the quartz diaphragm (3-4);

the silicon ring (3-3) is formed by cutting a monocrystalline silicon wafer by using an ultraviolet cutting machine;

the quartz diaphragm (3-4) is made of (NH)₄)₂SiF₆Placing the purified solution in a water bath kettle, stirring and heating to a certain temperature, adding ammonium fluorosilicate solution and 26 wt% of ammonia water, adding the ammonia water when the reaction end point is reached, aging while stirring, filtering, reserving filtrate, washing a filter cake for multiple times by using ultrapure water, adding a proper amount of ultrapure water into the filter cake, heating to 85 ℃, hot washing for 0.6h, carrying out solid-liquid separation while the mixture is hot, drying the filter cake for 2.5h at 120 ℃, calcining to obtain silicon dioxide, placing the silicon dioxide in a muffle furnace for calcining at 1310 ℃ and keeping the temperature for 3h for crystallization, and cutting crystals to obtain a quartz membrane;

the graphene (3-5) is prepared by adopting a liquid phase stripping method, and natural graphite, sulfuric acid and potassium dichromate are mixed according to a mass ratio of 1.5: 3: 0.2, uniformly mixing, fully reacting in a water bath at 100 ℃, then adding ionized water into reaction liquid for washing, filtering, drying at 50 ℃, puffing dried powder at 1200 ℃ for 10s, then putting the dried powder into an N-methylpyrimidine solvent, stirring at low speed for fully mixing, stripping the suspension by a high-pressure homogenizing device, circulating for 8 times under the pressure of 80MPa to obtain a graphene solution, and freeze-drying and pressurizing the graphene solution to prepare a graphene sheet;

the gold film (3-6) is obtained by an electron beam evaporation method, a standard silicon wafer is selected as a growing substrate, photoresist is coated on the silicon wafer, a gold film with the thickness of 200nm grows on the photoresist by the electron beam evaporation method, then a gold film sample is adhered to a sensing device and is placed in an acetone solution containing 99.7% of analytical pure concentration, after standing for 13h, the photoresist is corroded, the gold film is completely separated from the silicon wafer substrate, and film coating is completed;

the single-mode optical fiber (3-1) in the sensing unit (3) is inserted into the glass ferrule (3-2), and the glass ferrule (3-2), the silicon ring (3-3), the quartz diaphragm (3-4), the graphene (3-5) and the gold film (3-6) are sequentially stacked, bonded and packaged to form the sensing unit (3);

the specific preparation process of the sensing unit (3) comprises the steps of selecting the size of a component, dividing the component, placing the component and packaging the component;

wherein: the size selection of the parts comprises selecting a circular diaphragm with the thickness of 61 mu m and the diameter of 4mm of a quartz diaphragm (3-4), and selecting a silicon ring (3-3) with the outer diameter of 3mm, the inner diameter of 2mm and the thickness of 40 mu m;

the part segmentation comprises the cutting of a silicon ring (3-3) and the cutting of a quartz diaphragm (3-3), firstly, a circular ring with the outer diameter of 3mm, the inner diameter of 2mm and the thickness of 40 mu m is cut in monocrystalline silicon of the silicon ring (3-3), and the quartz diaphragm with the diameter of 5mm is cut on a quartz diaphragm with the thickness of 22 mu m and two polished surfaces;

the placement position of the components comprises the steps that a quartz diaphragm (3-4) and a silicon ring (3-3) are sequentially stacked on a high-temperature heating table, a glass insertion core (3-2) with the outer diameter of 3mm is placed on the silicon ring (3-3), and the glass insertion core (3-2) is aligned with the centers of the silicon ring (3-3), the quartz diaphragm (3-4) and graphene (3-5);

the packaging of the component comprises the steps of sealing a glass ferrule (3-2), a silicon ring (3-3) and a quartz diaphragm (3-4) with graphene (3-5) by using an adhesive, then inserting a cut and flat single-mode optical fiber (3-1) into a proper position of the glass ferrule (3-2), pre-fixing by using ultraviolet glue, then completely fixing by using epoxy resin, and standing for 48 hours;

the silicon ring (3-3) in the sensing unit (3) is made of monocrystalline silicon and is cut by an ultraviolet cutting machine.

2. An optical fiber sensing device based on ultrasonic detection voltage and an implementation method are characterized in that:

the ASE light source (1) emits light beams to be transmitted to the optical fiber coupler (2), the optical fiber coupler (2) outputs the light beams to be transmitted to the sensing unit (3), the light beams are reflected and transmitted in the sensing unit (3), when the sensing unit (3) is placed in the ultrasonic conversion device (4), the gold film (3-6), the graphene (3-5) and the quartz diaphragm (3-4) in the sensing unit (3) deform, so that the silicon ring (3-3) changes correspondingly, the air Fabry-Perot cavity changes in conversion, the optical path of reflected light is influenced, and then generates the interference of light, the interference light returns to the optical fiber coupler (2) through the single-mode optical fiber (3-1) and is transmitted to the photoelectric converter (5) through the optical fiber coupler (2), the photoelectric converter (5) generates an analog signal and transmits the analog signal to the signal processing module (6) for data processing.

3. The optical fiber sensing device based on ultrasonic detection voltage and the realization method thereof according to claim 2 are characterized in that:

the ASE light source (1) is a broadband light source, and the central wavelength is 1550nm for generating light signals.

4. The optical fiber sensing device based on ultrasonic detection voltage and the realization method thereof according to claim 2 are characterized in that:

the ultrasonic conversion device (4) comprises a shell (4-1), a harmonic oscillator (4-2), an amplitude transformer (4-3), electrode plates (4-4) and piezoelectric crystals (4-5), wherein the electrode plates (4-4) are respectively connected with the positive electrode and the negative electrode of a power supply, different voltages are applied to the electrode plates (4-4) to change the thickness of the piezoelectric crystals (4-5), and vibration caused by telescopic conversion is amplified through the energy accumulation effect of the amplitude transformer (4-3) and transferred to the harmonic oscillator (4-2) to emit ultrasonic waves.

5. The optical fiber sensing device based on ultrasonic detection voltage and the realization method thereof according to claim 2 are characterized in that:

the signal processing module (6) comprises an A/D module (6-1), a data buffer module (6-2), an IIC serial port (6-3) and a host (6-4) which are connected in sequence.

6. The optical fiber sensing device based on ultrasonic detection voltage and the realization method thereof according to claim 2 are characterized in that: the signal processing module (6) is characterized in that an analog signal generated by the photoelectric converter (5) enters the signal processing module (6), the analog signal and a digital signal are converted through the A/D module (6-1) in the signal processing module (6), the output digital signal is input to the data buffering module (6-2) to buffer the digital signal, then the signal is transmitted to the host (6-4) through the IIC serial port (6-3), and data is displayed in the host (6-4).

Technical Field

The invention belongs to the technical field of optical fiber sensing, and particularly relates to an optical fiber sensing device based on ultrasonic detection voltage and an implementation method.

Background

At present, the optical fiber sensing technology is gradually improved, and the monitoring device of optical fiber sensing is also gradually improved, wherein in the optical fiber sensing device, the medium material and the structure of the sensing device can generate great influence on the optical fiber sensing. At present, there are many apparatuses and methods for realizing ultrasonic detection by using optical methods.

Zhang Hui et al (Zhang Hui, Li Zhi, Zheng Guanru, etc.; design of air coupling capacitance type micro ultrasonic transducer [ J ] Acoustics report, 01, 2019, page 116, 142) propose a method of air coupling capacitance type micro ultrasonic transducer, which is to simultaneously connect DC bias voltage and AC excitation voltage between upper and lower electrodes, and the diaphragm vibrates under the action of electrostatic force to radiate ultrasonic wave. Fu et al (Fu, YD; Sun, S; Zhuo, CW; et al. Piezoelectric Micromachined Transducer with Superior Acoustic output for Pulse-Echo Imaging Application [ J ]. IEEE Electron,2020.3018310) propose a novel structure of piezoelectric Micromachined Ultrasonic Transducer based on an aluminum nitrate film, in which the thicker bottom electrode achieves an electrically conductive connection by thickening the bottom electrode in a sandwich structure and moves down along the neutral surface of the sandwich structure outside the piezoelectric layer, and Ultrasonic waves are emitted by means of a switch by means of pressure vibration. The patent refers to the field of 'transducers'.

Although the above researchers use a method of applying a voltage between electrodes to make the diaphragm vibrate and radiate ultrasonic waves, or increase the thickness of an electrode sheet, reduce capacitance loss, and increase the ultrasonic waves through the vibration of the diaphragm, or design a composite transducer, the measurement range, the measurement accuracy and the portability of the device are greatly improved compared with the conventional ultrasonic monitoring device; the piezoelectric micro-mechanical ultrasonic transducer based on the aluminum nitrate film proposed by Fu et al can only reach dozens of pascals/volt by the ultrasonic pressure transmitted by a single vibration element, and is too small, and a plurality of units are needed to meet the emission requirement of the ultrasonic device. The sandwich type composite transducer proposed by the huh et al is damaged in the stretching stage when the cementing layer is under the condition of large amplitude, so that the optical fiber sensing device for detecting the voltage by ultrasonic waves and the implementation method thereof are provided, wherein the optical fiber sensing device has the advantages of higher sensitivity, good stability and higher efficiency, and is used for solving the problems that the sensitivity is not high, the efficiency is low, the influence of the external environment is easy to influence and the like in the prior art.

Disclosure of Invention

The technical scheme adopted by the invention for solving the technical problems is as follows:

the technical scheme is as follows: an optical fiber sensing device for detecting voltage based on ultrasonic waves and an implementation method thereof are characterized by comprising an ASE light source (1), an optical fiber coupler (2), a sensing unit (3), an ultrasonic wave conversion device (4), a photoelectric converter (5) and a signal processing module (6);

the sensing unit (3) comprises a single-mode fiber (3-1), a glass ferrule (3-2), a silicon ring (3-3), a quartz diaphragm (3-4), graphene (3-5) and a gold film (3-6), wherein:

an air Fabry-Perot cavity is formed by the inner surfaces of the single-mode optical fiber (3-1) and the quartz diaphragm (3-4), the cavity length of the air Fabry-Perot cavity is about 26 mu m, the quartz diaphragm (3-4) forms a silicon Fabry-Perot cavity, and the cavity length of the silicon Fabry-Perot cavity is 40 mu m of the thickness of the quartz diaphragm (3-4);

the silicon ring (3-3) is formed by cutting a monocrystalline silicon wafer by using an ultraviolet cutting machine;

the quartz diaphragm (3-4) is made of (NH)₄)₂SiF₆Placing the purified solution in a water bath kettle, stirring and heating to a certain temperature, adding ammonium fluorosilicate solution and 26 wt% of ammonia water, adding ammonia water when the reaction end point is reached, aging under stirring, filtering, reserving filtrate, washing filter cake for multiple times with ultrapure water, adding a proper amount of ultrapure water into the filter cake, heating to 85 ℃, washing for 0.6h, separating solid from liquid while hot, drying the filter cake for 2.5h at 120 ℃, calcining to obtain silicon dioxide, placing the silicon dioxide in a water bath kettlePlacing the quartz membrane in a muffle furnace for 1310 ℃ calcination and heat preservation for 3 hours for crystallization, and cutting the crystal to obtain a quartz membrane;

the graphene (3-5) is prepared by adopting a liquid phase stripping method, and natural graphite, sulfuric acid and potassium dichromate are mixed according to a mass ratio of 1.5: 3: 0.2, uniformly mixing, fully reacting in a water bath at 100 ℃, then adding ionized water into reaction liquid for washing, filtering, drying at 50 ℃, puffing dried powder at 1200 ℃ for 10s, then putting the powder into an N-methylpyrrolidone solvent, stirring at a low speed for fully mixing, stripping the suspension by a high-pressure homogenizing device, circulating for 8 times under the pressure of 80MPa to obtain a graphene solution, and freeze-drying and pressurizing the graphene solution to prepare a graphene sheet;

the gold film (3-6) is obtained by an electron beam evaporation method, a standard silicon wafer is selected as a growing substrate, photoresist is coated on the silicon wafer, a gold film with the thickness of 200nm grows on the photoresist by the electron beam evaporation method, then a gold film sample is adhered to a sensing device and is placed in an acetone solution containing 99.7% of analytical pure concentration, after standing for 13h, the photoresist is corroded, the gold film is completely separated from the silicon wafer substrate, and film coating is completed;

the single-mode optical fiber (3-1) in the sensing unit (3) is inserted into the glass ferrule (3-2), and the glass ferrule (3-2), the silicon ring (3-3), the quartz diaphragm (3-4), the graphene (3-5) and the gold film (3-6) are sequentially stacked, bonded and packaged to form the sensing unit (3);

the specific preparation process of the sensing unit (3) comprises the steps of selecting the size of a component, dividing the component, placing the component and packaging the component;

wherein: the size selection of the parts comprises selecting a circular diaphragm with the thickness of 61 mu m and the diameter of 4mm of a quartz diaphragm (3-4), and selecting a silicon ring (3-3) with the outer diameter of 3mm, the inner diameter of 2mm and the thickness of 40 mu m;

the part segmentation comprises the cutting of a silicon ring (3-3) and the cutting of a quartz diaphragm (3-4), firstly, a circular ring with the outer diameter of 3mm, the inner diameter of 2mm and the thickness of 40 mu m is cut in monocrystalline silicon of the silicon ring (3-3), and the quartz diaphragm with the diameter of 5mm is cut on a quartz diaphragm with the thickness of 22 mu m and two polished surfaces;

the placement position of the components comprises the steps that a quartz diaphragm (3-4) and a silicon ring (3-3) are sequentially stacked on a high-temperature heating table, a glass insertion core (3-2) with the outer diameter of 3mm is placed on the silicon ring (3-3), and the glass insertion core (3-2) is aligned with the centers of the silicon ring (3-3), the quartz diaphragm (3-4) and graphene (3-5);

the packaging of the component comprises the steps of sealing a glass ferrule (3-2), a silicon ring (3-3) and a quartz diaphragm (3-4) with graphene (3-5) by using an adhesive, then inserting a cut and flat single-mode optical fiber (3-1) into a proper position of the glass ferrule (3-2), pre-fixing by using ultraviolet glue, then completely fixing by using epoxy resin, and standing for 48 hours;

the silicon ring (3-3) in the sensing unit (3) is made of monocrystalline silicon and is cut by an ultraviolet cutting machine.

An optical fiber sensing device based on ultrasonic detection voltage and an implementation method are characterized in that:

the ASE light source (1) emits light beams to be transmitted to the optical fiber coupler (2), the optical fiber coupler (2) outputs the light beams to be transmitted to the sensing unit (3), the light beams are reflected and transmitted in the sensing unit (3), when the sensing unit (3) is placed in the ultrasonic conversion device (4), the gold film (3-6), the graphene (3-5) and the quartz diaphragm (3-4) in the sensing unit (3) deform, so that the silicon ring (3-3) changes correspondingly, the air Fabry-Perot cavity changes, the optical path of reflected light is influenced, further generating the interference of light, returning the interference light to the optical fiber coupler (2) through the single-mode optical fiber (3-1) and transmitting the interference light to the photoelectric converter (5) through the optical fiber coupler, the photoelectric converter (5) generates an analog signal and transmits the analog signal to the signal processing module (6) for data processing.

Further, the ASE light source (1) is a broadband light source having a center wavelength of 1550nm for generating an optical signal.

Furthermore, the ultrasonic conversion device (4) comprises a shell (4-1), a harmonic oscillator (4-2), an amplitude transformer (4-3), electrode plates (4-4) and piezoelectric crystals (4-5), wherein the electrode plates (4-4) are respectively connected with the positive electrode and the negative electrode of a power supply, voltage is generated and passes through the electrode plates (4-4), the thickness of the piezoelectric crystals (4-5) is changed by inputting different voltages, and vibration caused by telescopic conversion is amplified through the energy gathering effect of the amplitude transformer (4-3) and transferred to the harmonic oscillator (4-2) to emit ultrasonic waves.

Furthermore, the signal processing module (6) comprises an A/D module (6-1), a data buffer module (6-2), an IIC serial port (6-3) and a host (6-4) which are connected in sequence.

Furthermore, in the signal processing module (6), an analog signal generated by the photoelectric converter (5) enters the signal processing module (6), the analog signal and a digital signal are converted through the A/D module (6-1) in the signal processing module (6), the output digital signal is input to the data buffer module (6-2) for buffering of the digital signal, and then the signal is transmitted to the host (6-4) through the IIC serial port (6-3), and data is displayed in the host (6-4).

The invention has the structure that: an optical fiber sensing device based on ultrasonic detection voltage and an implementation method.

Compared with the prior art, the invention has the beneficial effects that:

the invention realizes the voltage detection by ultrasonic waves, has convenient and simple structure, improves the sensitivity of the device and the operation period, and greatly reduces the problems of low sensitivity and easy influence of external environmental factors of the detection device.

According to the invention, the strain of the gold film and the graphene to the sound pressure of the ultrasonic wave causes the quartz diaphragm to deform, so that the length of the Fabry-Perot cavity is directly changed, and the change is irrelevant to the binder, so that the measurement sensitivity is improved, and the measurement sensitivity is improved by 30% after the implementation of the invention.

The ultrasonic conversion device is designed, the number of electrode plates is increased, the voltage stability of the piezoelectric wafer can be ensured, the same-amplitude expansion is generated, and the expansion amplitude of the piezoelectric module is increased; the amplitude transformer penetrates through the piezoelectric wafer and the electrode plate but does not penetrate through the last electrode plate, so that the sensing of vibration amplitude is enhanced, the attenuation degree of sound wave in the medium is reduced, the amplitude transformer is connected with the harmonic oscillator to enable the ultrasonic wave to be directly emitted, the frequency bandwidth of the ultrasonic wave is increased by 35% by the structure, the measurement accuracy and the long-term operation stability are improved by 40% after the ultrasonic wave measuring device is implemented.

Drawings

Fig. 1 is a structural diagram of an optical fiber sensing device for detecting voltage based on ultrasonic waves and an implementation method thereof.

Fig. 2 is a structural diagram of a sensing unit of an optical fiber sensing device based on ultrasonic detection voltage and an implementation method thereof.

Fig. 3 is a structural diagram of an ultrasonic transducer of an optical fiber sensing device based on ultrasonic detection voltage and an implementation method thereof.

Fig. 4 is a detailed diagram of a signal processing module of an optical fiber sensing device for detecting voltage based on ultrasonic waves and an implementation method thereof.

Detailed Description

The following embodiments will describe specific implementations of an optical fiber sensing device and an implementation method based on ultrasonic detection voltage according to the present invention with reference to the accompanying drawings.

As shown in FIG. 1, for the structure diagram of the optical fiber sensing device and the implementation method based on the ultrasonic detection voltage provided by the present invention, ASE light source (1) emits light beam to transmit to optical fiber coupler (2), optical fiber coupler (2) outputs light beam to transmit to sensing unit (3), light beam is reflected and transmitted in sensing unit (3), when sensing unit (3) is placed in ultrasonic conversion device (4), under the action of ultrasonic conversion device (4), quartz diaphragm (3-4) of sensing unit (3) is deformed, air Fabry-Perot cavity formed by silicon ring (3-3) is changed, optical path of reflected light is affected, and then light interference is generated, interference light returns to optical fiber coupler (2) through single mode optical fiber (3-1) and is transmitted to photoelectric converter (5) through optical fiber coupler (2), the photoelectric converter (5) generates an analog signal and transmits the analog signal to the signal processing module (6) for data processing.

As shown in fig. 2, for the structure diagram of the sensing unit of the optical fiber sensing device and the implementation method based on the ultrasonic detection voltage provided by the invention, a single-mode optical fiber (3-1) in the sensing unit (3) is inserted into a glass ferrule (3-2), the glass ferrule (3-2), a silicon ring (3-3), a quartz diaphragm (3-4), graphene (3-5) and a gold film (3-6) are sequentially stacked, bonded and encapsulated to form the sensing unit (3), and the sensing unit (3) is an air Fabry-Perot cavity formed by the inner surface of the quartz diaphragm (3-4), the end surface of the single-mode optical fiber (3-1), the silicon ring (3-3) and air in the sensing unit (3) to detect the change of ultrasonic detection; when light is transmitted into the single-mode optical fiber (3-1), the light is reflected and transmitted on the inner surface of the quartz diaphragm (3-4), the air Fabry-Perot cavity is changed due to the action of the silicon ring (3-3), the optical path of the reflected light is changed to form interference, an interference spectrum is generated, the transmitted light generated on the inner surface of the quartz diaphragm (3-4) generates the reflected light in the quartz diaphragm (3-4), and further the voltage is measured.

As shown in fig. 3, a detailed view of an ultrasonic transducer apparatus for detecting voltage based on ultrasonic waves and an implementation method thereof are provided. The ultrasonic conversion device (4) comprises a shell (4-1), a harmonic oscillator (4-2), an amplitude transformer (4-3), an electrode plate (4-4) and a piezoelectric crystal (4-5), wherein the electrode plate (4-4) is respectively connected with the positive electrode and the negative electrode of a power supply, different voltages are applied to the electrode plate (4-4) to change the thickness of the piezoelectric crystal (4-5), and vibration caused by telescopic conversion is amplified through the energy accumulation effect of the amplitude transformer (4-3) and transferred to the harmonic oscillator (4-2) to emit ultrasonic waves.

As shown in fig. 4, a detailed diagram of a signal processing module of an optical fiber sensing device and an implementation method thereof based on ultrasonic detection of voltage is provided for the present invention. The signal processing module (6) is used for enabling an analog signal generated by the photoelectric converter (5) to enter the signal processing module (6), converting the analog signal and a digital signal through the A/D module (6-1) in the signal processing module (6), inputting the digital signal output by the signal processing module into the data buffering module (6-2) for buffering the digital signal, then transmitting the signal to the host (6-4) through the IIC serial port (6-3), and displaying data in the host (6-4). The output of the host (6-4) is realized, and real-time monitoring is carried out.