CN116929535B - Optical fiber micro-ring hydrophone based on composite film sensitization - Google Patents
Optical fiber micro-ring hydrophone based on composite film sensitization Download PDFInfo
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- CN116929535B CN116929535B CN202310893537.4A CN202310893537A CN116929535B CN 116929535 B CN116929535 B CN 116929535B CN 202310893537 A CN202310893537 A CN 202310893537A CN 116929535 B CN116929535 B CN 116929535B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
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Abstract
本发明公开了一种基于复合薄膜增敏的光纤微环水听器，其中，水听器由单模光纤制成的光纤微环和复合薄膜组成。当水下低频声波打在微环上时，由于受到外界压力的影响，导致光纤微环折射率以及周长发生变化，进而导致谐振谱线发生偏移，同一波长点的强度发生变化，通过该波长点的强度变化来检测外界声波信号的频率及幅值大小，实现外界声波的检测。复合薄膜主要作用是为了与外界声波产生共振，利用复合薄膜的共振变形来增加光纤微环的形变，进一步提高声压灵敏度。本发明的水听器可以避免电磁干扰、稳定性好、小型化；另外，可以通过改变复合薄膜的厚度和半径来调谐共振点，实现声波频率点检测的可调谐，同时可以进一步提高声压灵敏度。
The present invention discloses an optical fiber microring hydrophone based on composite film sensitization, wherein the hydrophone is composed of an optical fiber microring made of a single-mode optical fiber and a composite film. When an underwater low-frequency sound wave hits the microring, due to the influence of external pressure, the refractive index and circumference of the optical fiber microring change, which in turn causes the resonance spectrum to shift, and the intensity of the same wavelength point changes. The frequency and amplitude of the external sound wave signal are detected by the intensity change of the wavelength point, thereby realizing the detection of the external sound wave. The main function of the composite film is to resonate with the external sound wave, and the resonant deformation of the composite film is used to increase the deformation of the optical fiber microring, thereby further improving the sound pressure sensitivity. The hydrophone of the present invention can avoid electromagnetic interference, has good stability, and is miniaturized; in addition, the resonance point can be tuned by changing the thickness and radius of the composite film, thereby realizing the tunability of the sound wave frequency point detection, and at the same time, the sound pressure sensitivity can be further improved.
Description
Technical Field
The invention relates to the field of sensors, in particular to an optical fiber micro-ring hydrophone based on compound film sensitization.
Background
The optical fiber hydrophone is a device for detecting underwater low-frequency sound waves by utilizing an optical fiber technology, and detects the frequency and amplitude of the sound waves by changing an optical signal of the optical fiber hydrophone, and the optical fiber hydrophone slowly replaces piezoelectric sound sensors in the fields of sound wave detection, submarine detection, marine resource exploration and passive sonar by virtue of the advantages of small volume, strong electromagnetic interference resistance, high sensitivity and the like.
At present, in the field of underwater low-frequency acoustic wave sensing, most optical fiber hydrophones are Fabry-Perot (FP) acoustic wave sensors, but the manufacturing process of the sensors is complex and the cost is high, and for the optical fiber micro-ring hydrophones, the optical fiber micro-ring hydrophones have become a new research trend by virtue of the advantages of simplicity and convenience in manufacturing, low cost, high quality factor and the like, so that the optical fiber micro-ring hydrophones have high research value. The invention combines the optical fiber micro-ring and the composite film together, thereby greatly improving the sensitivity of underwater low-frequency sound wave detection.
Disclosure of Invention
Aiming at the fact that most traditional hydrophones are piezoelectric acoustic sensors, electromagnetic interference is easy to receive, and the optical fiber micro-ring hydrophone is not suitable for severe environments, the optical fiber micro-ring hydrophone based on composite film sensitization is provided, and the optical fiber micro-ring hydrophone is simple in manufacturing process, low in cost, high in sensitivity and capable of achieving tunable detection of acoustic wave frequency points.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The invention provides an optical fiber micro-ring hydrophone based on sensitization of a composite film, which is characterized by comprising an optical fiber micro-ring and a composite film, wherein the composite film is bonded on a glass substrate with a hole at the bottom with a certain diameter by plasma, the optical fiber micro-ring is solidified and packaged in the middle of the composite film, the corresponding optical fiber micro-ring is right above a through hole, when underwater low-frequency sound waves strike on the composite film, the deformation of the optical fiber micro-ring is increased by utilizing the resonance of the composite film, so that a sensitization effect is achieved on the detection of the underwater low-frequency sound waves, and the manufacturing process and the packaging technology of the hydrophone comprise the following steps:
pulling and knotting a single-mode fiber into a fiber micro-ring;
Glass gaskets with certain thickness are fixed on two sides of the glass substrate with the holes at the bottom, and the bottom PDMS film is bonded to the glass substrate with the holes at the bottom through plasma;
Placing an optical fiber micro-ring on a bottom PDMS film, wherein a through hole of a glass substrate with a hole at the bottom is arranged right below the optical fiber micro-ring, then dripping low refractive index adhesive MY-132-A on the optical fiber micro-ring, and wrapping the optical fiber micro-ring;
Then, packaging the two ends of the optical fiber micro-ring by using PDMS solution, and sealing by using two side stop blocks to prevent the solution from overflowing;
And bonding the top PDMS film to a glass cover plate with a hole at the top through plasma, covering the glass cover plate on a glass gasket, curing the low refractive index adhesive MY-132-A by using an ultraviolet lamp in an oxygen-free environment, and finally fixing the cover plates at two sides of the top glass on the two side check blocks.
Further, the diameter of the optical fiber micro-ring is 200-800 mu m, and the diameter of the micro-nano optical fiber is 2-4 mu m.
Further, the composite film consists of three layers of films, namely a bottom PDMS film, a low refractive index adhesive MY-132-A and a top PDMS film.
Furthermore, the PDMS film is colorless, odorless, corrosion-resistant, good in material chemical property, and smaller in refractive index than the refractive index of the fiber core, can prevent a large amount of light leakage in the fiber micro-ring, and the refractive index of the low refractive index adhesive MY-132-A is 1.32, is a good optical packaging material, and can be cured through irradiation of an ultraviolet lamp under an anaerobic condition to package the fiber micro-ring, form a protective layer and prevent light leakage.
Further, the sensing principle of the hydrophone is based on the change of the refractive index and the circumference of the optical fiber micro-ring, and as the resonant wavelength of the optical fiber micro-ring is required to meet the condition lambda=2pi n eff R/m, when external sound waves strike on the composite film, the effective refractive index n eff and the radius R of the optical fiber micro-ring can be changed due to the resonance of the composite film, so that the resonant wavelength lambda of the optical fiber micro-ring can be deviated.
Further, the demodulation algorithm of the hydrophone is based on intensity demodulation, when the resonance wavelength is shifted, the intensity of the same wavelength point before and after the shift is changed, and then compared with the reference hydrophone, the frequency and the sensitivity of the external sound wave are demodulated through the change of the intensity.
Further, in the demodulation algorithm of the hydrophone, the working wavelength is unstable due to thermal noise of the tunable laser and other devices, and the working point is deviated, so that the working point wavelength needs to be measured and judged through direct current output by the photoelectric detector, a direct current component obtained by signal processing is compared with a preset range, if the direct current component is between the preset range, the output wavelength of the laser is not changed, otherwise, the output wavelength of the laser is changed, and the working point is locked.
Compared with the prior art, the optical fiber micro-ring hydrophone based on the sensitization of the composite film has the advantages of electromagnetic interference resistance, good stability, high sensitivity, simple manufacturing process and low cost, and the optical fiber micro-ring is combined with the composite film, so that when underwater low-frequency sound waves strike on the composite film, the deformation of the optical fiber micro-ring is increased by utilizing the resonance deformation of the composite film, and the sound pressure sensitivity is further improved.
Drawings
FIG. 1 is a flow chart of a process for manufacturing an optical fiber micro-ring hydrophone based on composite film sensitization in an embodiment of the invention.
FIG. 2 is an isometric view of a composite film sensitized optical fiber micro-ring hydrophone according to an embodiment of the present invention.
FIG. 3 is an exploded view of a fiber optic microring hydrophone structure based on composite film sensitization in accordance with an embodiment of the present invention.
Fig. 4 is a diagram of an experimental apparatus for underwater low-frequency acoustic wave detection according to an embodiment of the present invention.
FIG. 5 is a time domain and frequency domain response chart of an optical fiber micro-ring hydrophone based on composite film sensitization and a reference hydrophone to an acoustic wave signal with the frequency of 1.6 kHz.
FIG. 6 is a graph showing the relationship between output voltage and sound pressure of an optical fiber micro-ring hydrophone based on composite film sensitization in an embodiment of the invention at a sound wave frequency of 1 kHz.
Description of the reference numerals
1-Bottom perforated glass substrate, 2-glass spacer, 3-bottom PDMS film, 4-optical fiber micro-ring, 5-low refractive index glue MY-132-A,6-PDMS solution, 7-two side stops, 8-top PDMS film, 9-top perforated glass cover plate, 10-top glass two side cover plate, 11-computer, 12-data acquisition card, 13-photodetector, 14-vibrating table, 15-rigid wall round tube, 16-water, 17-reference hydrophone, 18-power amplifier, 19-signal generator, 20-polarizer, 21-tunable laser
Detailed Description
The invention will be further described with reference to the accompanying drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
As shown in fig. 1, the embodiment provides a flow chart of a manufacturing process of an optical fiber micro-ring hydrophone based on composite film sensitization, which comprises the following steps:
And S1, tapering and knotting the single-mode fiber into an optical fiber micro-ring 4.
Taking a section of single-mode fiber with the length of 30cm, removing a section of coating layer with the length of 5cm from the middle of the single-mode fiber by using an optical fiber wire stripper, then placing the single-mode fiber on clamps at two ends of a tapering platform, aligning the part from which the coating layer is removed with oxyhydrogen flame, adjusting the distance and the height between the oxyhydrogen flame and the optical fiber, setting the parameters of a stepping motor, slowly driving the optical fiber to pull towards two ends, gradually pulling the diameter of the optical fiber to 2-4 mu m, then turning off the oxyhydrogen flame and the stepping motor, taking down the optical fiber, manually beating a ring with the diameter of 2cm, fixing the optical fiber on clamps at two ends, adjusting the parameters of the stepping motor, and slowly driving the optical fiber to pull towards two ends until the diameter of the optical fiber micro-ring 4 is pulled to 200-800 mu m.
And S2, fixing glass gaskets 2 with certain thickness on two sides of the bottom glass substrate 1 with holes, and bonding the bottom PDMS film 3 onto the bottom glass substrate 1 with holes through plasma.
The method comprises the steps of punching a through hole with a certain diameter on a glass substrate, cleaning the surface of the bottom glass substrate with holes (1), fixing glass gaskets with a certain thickness on two sides of the glass substrate with holes by ultraviolet light curing glue, putting the bottom glass substrate with holes (1) and the bottom PDMS film (3) into a plasma cleaning machine, and bonding the bottom glass substrate with holes (1) and the bottom PDMS film (3) after plasma treatment.
And S3, placing the optical fiber micro-ring 4 on the bottom PDMS film 3, wherein a through hole of the glass substrate 1 with a hole at the bottom is arranged right below the optical fiber micro-ring 4, and then dripping low refractive index adhesive MY-132-A5 on the optical fiber micro-ring 4 and wrapping the optical fiber micro-ring 4.
The optical fiber micro-ring 4 is placed on the bottom PDMS3 film, the refractive index of PDMS is about 1.40, which is slightly smaller than that of the optical fiber core, so that a large amount of light leakage can be prevented, the through hole of the glass substrate 1 with the hole at the bottom is just arranged under the optical fiber micro-ring 4, the deformation of the bottom PDMS film 3 is mainly caused by sound waves to drive the refractive index and the circumference of the optical fiber micro-ring 4 to change, the sound pressure sensitivity is improved, then the low refractive index glue MY-132-A is dripped on the optical fiber micro-ring 4, the refractive index of the glue is 1.32, and the glue is also good optical packaging glue, so that the optical fiber micro-ring 4 is wrapped, and the light leakage is prevented.
And S4, placing two ends of the optical fiber micro-ring 4 in a PDMS solution 6 for packaging, and sealing by using two side stoppers 7 to prevent the solution from overflowing.
And mixing PDMS and a curing agent according to the mass ratio of 10:1, uniformly stirring, vacuumizing to eliminate bubbles in the solution, covering two ends of the optical fiber micro-ring 4 with the PDMS solution 6, packaging, and sealing by using two side stop blocks 7 to prevent the solution from overflowing.
And S5, bonding the top PDMS film 8 to a top glass cover plate 9 with holes through plasma, then covering the top PDMS film on the glass gasket 2 together, curing the low refractive index adhesive MY-132-A5 by using an ultraviolet lamp in an oxygen-free environment, and finally fixing the cover plates 10 on two sides of the top glass on the two side stop blocks 7.
As shown in fig. 2, an embodiment of the present invention provides an isometric view of a fiber micro-ring hydrophone based on composite film sensitization.
As shown in FIG. 3, an embodiment of the invention provides an exploded view of a fiber optic microring hydrophone structure based on composite film sensitization.
As shown in FIG. 4, the embodiment of the invention provides an experimental device diagram for underwater low-frequency sound wave detection.
The tunable laser 21 outputs the wavelength of a certain wave band, the wavelength passes through the polarizer 20, the resonant mode is excited by the optical fiber micro-ring 4 to generate the resonant wavelength, when the sound wave strikes on the composite film to cause the deviation of the resonant wavelength of the optical fiber micro-ring 4, the photoelectric detector 13 converts the optical signal into an electric signal, the electric signal is transmitted to the data acquisition card 12 for storage, the computer end 11 is connected for intensity demodulation of the signal, the frequency and amplitude of the corresponding sound wave are demodulated, and then the frequency and amplitude of the corresponding sound wave are compared with the signal of the reference hydrophone 17 to obtain the corresponding sound pressure sensitivity.
The underwater low-frequency sound wave is a sine signal with a certain frequency sent by a signal generator 19, passes through a power amplifier 18 and then drives a vibrating table 14 to vibrate, so that the sound wave with a corresponding frequency is generated in water 16 of a rigid-wall circular tube 15, and a reference hydrophone 17 is calibrated according to national standards and directly transmits the signal to a data acquisition card 12.
When the signal generator 19 drives the vibration table 14 to emit sound waves with a certain frequency, the composite film generates resonance deformation when the sound waves are applied to the composite film, so that the refractive index and the circumference of the optical fiber micro-ring 4 are changed, the resonance wavelength is shifted, the intensity of the same wavelength point before and after the shift is changed, and the frequency and the amplitude of the corresponding sound waves are demodulated through the intensity.
For better demodulation of the frequency and amplitude of the sound wave, the tunable laser 21 is used for spectral scanning, and the wavelength corresponding to the intermediate voltage value is approximately selected as the working wavelength, because the amplitude variation is relatively most obvious when the wavelength is subjected to the sound wave.
Considering that the working wavelength is unstable due to thermal noise of the tunable laser 21 and other devices, there is a working point shift, so that the working point wavelength needs to be measured and judged by the direct current output by the photodetector 13, the direct current component obtained by signal processing is compared with a preset range, if the direct current component is between the preset range, the output wavelength of the tunable laser 21 is not changed, otherwise, the output wavelength of the tunable laser 21 is changed, and the working point is locked.
As shown in FIG. 5, the embodiment of the invention provides a time domain and frequency domain response diagram of an optical fiber micro-ring hydrophone based on compound film sensitization and a reference hydrophone to an acoustic wave signal with the frequency of 1.6 kHz.
As shown in FIG. 6, the embodiment of the invention provides a relationship between output voltage and sound pressure of the optical fiber micro-ring hydrophone based on compound film sensitization under the condition that the sound wave frequency is 1 kHz.
The optical fiber micro-ring hydrophone sensitized by the composite film provided by the application is described in detail above. The description of the specific embodiments is only intended to aid in the understanding of the structure of the present application and its design. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.
Claims (7)
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| CN105319650A (en) * | 2015-12-09 | 2016-02-10 | 深圳市鼎硕同邦科技有限公司 | Full-optical-fiber type multi-wavelength etalon based on micro-nano optical fiber ring and manufacturing method of full-optical-fiber type multi-wavelength etalon |
| CN109029688A (en) * | 2018-08-06 | 2018-12-18 | 中国科学院电子学研究所 | Sensitizing type fibre-optical acoustic sensor probe and its sensitization structure |
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| US7587105B2 (en) * | 2004-09-08 | 2009-09-08 | The Regents Of The University Of Michigan | High frequency ultrasound detection using polymer optical-ring resonator |
| KR20220063246A (en) * | 2019-09-18 | 2022-05-17 | 워싱톤 유니버시티 | Ultrasonic sensing and imaging based on whispering gallery mode (WGM) microresonators |
| CN111579051A (en) * | 2020-05-18 | 2020-08-25 | 武汉理工大学 | Optical fiber metal foil coated underwater sound pressure sensitivity enhancing device |
| CN114859463B (en) * | 2022-04-29 | 2023-03-24 | 中山大学 | An on-chip microcavity ultrasonically sensitized hollowed-out chip and its preparation method |
| CN116067477B (en) * | 2022-12-15 | 2025-11-14 | 上海大学 | A diaphragm vibration-coupled waveguide microring ultrasonic sensor |
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| CN105319650A (en) * | 2015-12-09 | 2016-02-10 | 深圳市鼎硕同邦科技有限公司 | Full-optical-fiber type multi-wavelength etalon based on micro-nano optical fiber ring and manufacturing method of full-optical-fiber type multi-wavelength etalon |
| CN109029688A (en) * | 2018-08-06 | 2018-12-18 | 中国科学院电子学研究所 | Sensitizing type fibre-optical acoustic sensor probe and its sensitization structure |
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