CN112816054A - Optical fiber laser microphone with special-shaped spring type sensitivity enhancing structure - Google Patents
Optical fiber laser microphone with special-shaped spring type sensitivity enhancing structure Download PDFInfo
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Abstract
一种异形弹簧式增敏结构的光纤激光传声器，包括：异形弹簧、透声框架、一对固定盖板和光纤激光光纤光栅。本发明通过优化设计光纤激光传声器核心敏感元件异形弹簧，实现了结构简单、封装工艺简单、生产周期短、耐超高声压级、温漂小、工作带宽内响应平坦、性能稳定、一致性良好等优良性能，可实现宽频带范围内空气声信号的准确测量、灵敏度起伏小、实现超高声压级空气声信号的准确测量。
A fiber laser microphone with a special-shaped spring-type sensitization structure comprises: a special-shaped spring, a sound-transmitting frame, a pair of fixed cover plates and a fiber laser fiber grating. By optimizing the design of the special-shaped spring of the core sensitive element of the fiber laser microphone, the invention realizes simple structure, simple packaging process, short production cycle, ultra-high sound pressure level resistance, small temperature drift, flat response within the working bandwidth, stable performance and good consistency. It can achieve accurate measurement of airborne acoustic signals in a wide frequency range, with small fluctuations in sensitivity, and achieve accurate measurement of airborne acoustic signals at ultra-high sound pressure levels.
Description
Technical Field
The invention relates to an optical fiber laser microphone with a special-shaped spring type sensitization structure, and belongs to the technical field of underwater sound detection of optical fiber laser microphones. In particular to a fiber laser microphone which is resistant to ultrahigh sound pressure level signals and has flat low-frequency response.
Background
The aeroacoustic detection is the technical basis of research in various fields such as indoor acoustic research, street noise pollution research, aeroacoustic positioning, aeroacoustic physical research and the like, and the acoustic performance of the microphone is an important index for measuring the aeroacoustic detection capability and is the key research direction of various countries in the world at present. At present, the microphone can be divided into a piezoelectric microphone and an optical fiber microphone, and due to the advantages of high sensitivity, wide dynamic range of test, passive probe position, electromagnetic interference resistance, radiation resistance, corrosion resistance, skillful carrying, capability of being buried into a structure and the like, the microphone can realize the activities of special operations in extreme environments such as a strong magnetic environment, an underwater environment and the like, and can be applied to occasions with the requirement of eavesdropping prevention, the optical fiber microphone has become the mainstream direction of microphone research, and the microphone has better application prospects in airports, medical treatment and military.
The optical fiber microphone is mainly divided into three categories according to different sensing mechanisms: the Fabry-Perot cavity, the optical fiber white light interference type and the optical fiber grating type are easily influenced by the stability of light intensity, have strict requirements on the bending state of the optical fiber and the packaging structure of the microphone, and are not easy to implement in engineering application. Meanwhile, the serial connection of a plurality of microphone elements can be easily realized in one optical fiber through the wavelength division multiplexing technology, and the multipoint distribution measurement of different physical quantities is realized, so that the space of rear-end demodulation equipment is saved, the weight and the size of a microphone system are reduced, and the cost is reduced.
At present, the structures of the fiber laser microphone at home and abroad mainly comprise: the single optical fiber transmitting and receiving structure, the double optical fiber structure, the beam type optical fiber structure (single optical fiber transmitting, multiple optical fiber receiving forms), the vibration film type, the non-film type, the scattering lens type structure and other forms, different structural forms cause different inherent frequencies of the probe, the experimental effects are respectively different, but aiming at the problems that the microphone probe cannot bear ultrahigh pressure acoustic signals, the sensitivity flatness in a broadband range is poor, the packaging process is complex, miniaturization cannot be realized, and the cost is high, aiming at the phenomenon, aiming at the task requirements of ultrahigh sound pressure resistance level and low frequency response flatness, the low cost, the simple structure, the packaging process is simple, the performance is stable, the index requirements of good consistency are realized, and the design of a novel ultrahigh sound pressure resistance level signal low-cost and low-frequency response flat optical fiber laser microphone is urgently needed.
Patent CN 108174334 a "a vibrating diaphragm-free fiber laser microphone" proposes a fiber laser microphone that is not constrained by a vibrating diaphragm, but this patent still utilizes the refractive index of the optical transmission medium between two reflecting surfaces of the fabry-perot etalon to change with the sound field to realize the perception of the acoustic signal, wherein two coated reflecting mirrors are needed, the reflecting mirrors are directly exposed in the air, there are certain limiting requirements on the reflectivity and doping material of the coated reflecting mirrors, the upper limit of the length of the doped fiber reaches 10 cm, and the size is large. In summary, although this patent proposes a mode without a diaphragm, the actual package structure still contains an external exposed reflective film, which cannot bear the ultrahigh sound pressure signal. The used structure is too complex in production and assembly, the film mounting precision is high, and the consistency of batch production is difficult to guarantee. The patent does not see the acoustic performance data and simulation results of the microphone of the proposal.
Patent CN 109238437A "a optic fibre Fabry-Perot acoustic wave probe based on silicon nitride MEMS membrane" has proposed a silicon nitride MEMS etching diaphragm formula optic fibre Fabry-Perot microphone, this structure machining precision is extremely high, but adopt MEMS etching process, the degree of difficulty is very big, the cost is fairly high, need to guarantee in the implementation process that silicon nitride MEMS membrane and single mode fiber end face keep parallelism, need high accuracy three-dimensional micrometric displacement to adjust platform and packaging jig promptly, strict to the packaging process precision requirement, and do not see finished product or relevant experimental data at present, seriously influence the engineering application of optic fibre laser microphone.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the defects of the prior art are overcome, the optical fiber laser microphone with the special-shaped spring type sensitization structure is provided, and the problem of the low-frequency detection performance of the existing optical fiber laser microphone is solved. The optical fiber laser microphone has the advantages of simple structure, simple packaging process, short production period, low cost, flat low-frequency response, stable performance and good consistency, can realize accurate measurement of air acoustic signals in a wide frequency band range, has small sensitivity fluctuation, and meets special operation environments such as ultrahigh sound pressure.
The technical scheme of the invention is as follows: a profile spring type fiber laser microphone, comprising: the device comprises a pair of fixed cover plates, a special-shaped spring, a fixed connecting bolt, a protective frame, an armored optical cable and a phase shift grating;
the appearance structure of the pair of fixed cover plates is a hollow two-section stepped cylindrical table thin-wall structure, the special-shaped spring and the protective frame are inserted into the fixed cover plates from the inlet ends at the back sides of the bosses, two bolt countersunk holes are uniformly distributed in one small end face on one side of the trapezoidal surface boss and used for mounting and fixing the fixed cover plates and the special-shaped spring, four bolt hole positions are uniformly distributed in two peripheral end faces parallel to the small end faces and used for mounting and fixing the fixed cover plates and the protective frame, and the assembly among the pair of fixed cover plates, the special-shaped spring and the protective frame is completed through twelve fixed connecting bolts;
the special-shaped spring can be divided into three parts along the length direction, the three parts are sequentially a fan-shaped boss, a cuboid and a fan-shaped boss along the axial direction, and the cross section A of the special-shaped spring is symmetrical about the axial central point;
the middle section structure of the special-shaped spring is a cuboid, the cross section of the special-shaped spring is square, the side length-to-length ratio is 1:5, the axial length-to-cuboid length ratio of the fan-shaped boss is 1:10, the diameter-to-square side length ratio of the fan-shaped section is 1:1, the thickness-to-diameter ratio of the fan-shaped section is 7:10, and the plane side of the fan-shaped boss is the front side; the special-shaped spring is provided with a groove serving as an optical fiber placing groove on the axis of the protective frame, the opening direction of the optical fiber placing groove is the same as the front face of the fan-shaped boss, the special-shaped spring axially traverses three areas of the fan-shaped boss, the cuboid and the fan-shaped boss, the depth of the optical fiber groove and the length of the side length of the cuboid at the middle section are 1:2, the width of the optical fiber groove is 2mm, and the optical fiber groove is symmetrical about the center;
4 through square holes are uniformly distributed in a cuboid region at the middle section of the special-shaped spring, the opening direction of each square hole is in the same direction as that of the optical fiber groove, the width direction of each square hole is set along the axial direction of the special-shaped spring, the aspect ratio of each square hole is 4:3, and the distance between every two square holes is 8-10 mm;
the fan-shaped bosses at two sides of the special-shaped spring are respectively provided with two bolt fixing hole positions, and the fan-shaped bosses at two ends are inserted into the fixed cover plate along the axial direction and are fixedly connected with the fixed cover plate and the protective frame through fixed connecting bolts;
the phase-shift grating is placed in the optical fiber groove along the axis of the protective frame; two ends of the phase shift grating penetrate out of the central hole of the fixed cover plate;
the special-shaped spring is of a plane symmetrical structure, the cross section A of a symmetrical plane is positioned on the radial section where the midpoint of the axis of the protective frame is positioned, and the central plane B of the symmetrical plane penetrates through the center of the circle of the section of the fan-shaped circular truncated cone and is vertical to the bottom surface of the optical fiber groove;
the maximum equivalent outer diameter of the special-shaped spring is smaller than the inner diameter of the protection frame, and the special-shaped spring and the protection frame are not in contact;
the protective frame is of a thick-wall cylindrical structure, the ratio of inner diameter to outer diameter is 1:2, n circular holes are axially and uniformly distributed in the wall of the protective frame, the diameter of each circular hole is 6mm, the distance between every two circular holes is 8mm, and the circular holes are used as sound transmission windows;
four bolt fixing holes are uniformly distributed on two sides of the protective frame respectively;
a special-shaped spring is inserted into the protection frame along the axial direction, and the special-shaped spring and the protection frame are axially symmetrical about a central plane.
Further, the fixed cover plate, the special-shaped springs and the protective frame are made of invar steel; .
Further, the axial length of the front part of the special-shaped spring is sequentially A: b: a: c: d: d: d: d is 4:50: 4: 4: 3: 3: 3: 3;
wherein, the axial length of the fan-shaped boss of both sides is A, and the regional axial length of interlude cuboid is B, and the length and width that is located the quad slit in the regional interlude cuboid is C, D respectively.
Further, the thickness E and the diameter F of the fan-shaped boss satisfy the following proportional relation:
further, the phase shift grating is a fiber laser phase shift fiber grating.
Furthermore, a pretightening force F is applied to two ends of the phase-shift grating;
wherein E isfIs the modulus of elasticity of the phase-shifted grating, AfDelta lambda, the cross-sectional area of the phase-shifted gratingFFor the wavelength variation of the phase-shifted grating, λFK is a constant and not less than 1 for the center wavelength of the phase-shifted grating.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention discloses an optical fiber laser microphone packaging structure of a special-shaped spring type sensitization structure, which comprises an invar alloy special-shaped spring type structure, wherein a sensitization hole and a phase-shift grating distribution groove are formed in the invar alloy special-shaped spring type structure, polyurethane pouring sealant is filled in the invar alloy special-shaped spring type structure, and on the premise of ensuring the thin diameter of an optical fiber laser microphone, compared with the structures of vibration diaphragm type and film coating reflection layer type optical fiber microphones, an integrally poured metal structure has higher equivalent elastic modulus, the first-order resonance frequency of the microphone structure is improved, and therefore the optical fiber laser microphone has flat output response in a wide frequency band range;
2. according to the special-shaped spring structure, the sensitive structure of the fiber laser microphone is optimized, the sensitive unit phase shift grating is packaged in the fiber groove of the special-shaped spring, compared with a diaphragm type fiber laser microphone, on the premise that the resonance frequency of the sensitive structure is high enough, the sensitive unit is prevented from being directly exposed to the outside of the microphone, the sound receiving unit area of the microphone is increased through encapsulated polyurethane glue, and after the fiber laser microphone is excited by ultra-high sound pressure level sound waves, enough output response is achieved, so that the dynamic range of the fiber laser microphone is improved;
3. compared with the mode of a vibration diaphragm type and a coating reflection layer type, the special-shaped spring type optical fiber laser microphone can prevent impurities such as water vapor, tiny dust, debris and the like from permeating and adhering to a diaphragm, a reflection layer or an optical fiber end when the microphone is applied to a complex environment for a long time, so that the additional mass of a sensitive unit of the optical fiber laser microphone or the abnormal refractive index can be avoided, the reliability of the optical fiber laser microphone can be improved, the risk that foreign matters enter the microphone due to the long-time loss of a wind shield can be avoided, and the air sound measurement under the complex environment can be conveniently realized;
4. compared with a vibration diaphragm type optical fiber microphone and a silicon nitride MEMS diaphragm type optical fiber laser microphone, the special-shaped spring type optical fiber laser microphone has the advantages of simple structure, simple packaging process, less manual operation, short production period, low cost, excellent consistency and stability, no need of a high-precision sealing platform and capability of quickly realizing engineering application.
5. The structure of the special spring type optical fiber laser microphone comprises a pair of fixed cover plates, a special spring and a protective frame which are all made of invar alloy, the thermal expansion coefficient of the material is far lower than that of a conventional metal material and is close to that of a phase shift grating material, so that the temperature drift coefficient of the optical fiber laser microphone is convenient to reduce, and when the microphone is applied to a severe temperature environment, the test state of the optical fiber laser microphone can be ensured not to change, and the reliability of the microphone is ensured.
Drawings
FIG. 1 is an explanatory view of the axial dimension of the structure of the shaped spring 2 of the present invention;
FIG. 2 is a sectional dimension illustration of bosses on both sides of the shaped spring 2 according to the present invention;
FIG. 3 is a three-dimensional view of the structure of the contour spring type fiber laser microphone of the present invention;
FIG. 4 is a schematic diagram of the combination of the shaped spring 2 and the phase-shift grating 6 according to the present invention;
Detailed Description
In order to better understand the technical solutions, the technical solutions of the present application are described in detail below with reference to the drawings and specific embodiments, and it should be understood that the specific features in the embodiments and examples of the present application are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features in the embodiments and examples of the present application may be combined with each other without conflict.
The title provided by the embodiments of the present application is described in further detail below with reference to the drawings of the specification, and a specific implementation manner may include that shown in fig. 1: the device comprises a pair of fixed cover plates 1, special-shaped springs 2, fixed connecting bolts 3, a protective frame 4, an armored optical cable 5 and a phase-shift grating 6.
The appearance structure of the pair of fixed cover plates 1 is a hollow two-section stepped cylindrical table thin-wall structure, the special-shaped springs 2 and the protective frame 4 are inserted into the fixed cover plates from the inlet ends of the back sides of the bosses, two bolt countersunk holes are uniformly distributed in the small end face of one layer on one side of the boss of the trapezoidal surface and used for mounting and fixing the fixed cover plates 1 and the special-shaped springs 2, four bolt hole positions are uniformly distributed in the peripheral end faces of two layers parallel to the small end faces and used for mounting and fixing the fixed cover plates 1 and the protective frame 4, and the assembly among the fixed cover plates 1, the special-shaped springs 2 and the protective frame 4 is completed through twelve fixed connecting bolts 3.
The special-shaped spring 2 can be divided into three parts along the length direction, the three parts are sequentially a fan-shaped boss, a cuboid and a fan-shaped boss along the axial direction, and the cross section A of the special-shaped spring 2 is symmetrical about the axial center point.
The middle section structure of the special-shaped spring 2 is a cuboid, the cross section of the special-shaped spring is a square, the side length to length ratio is 1:5, the axial length to cuboid length ratio of the fan-shaped boss is 1:10, the diameter to square side length ratio of the fan-shaped section is 1:1, the thickness to diameter ratio of the fan-shaped section is 7:10, and the plane side of the fan-shaped boss is the front side. The special-shaped spring 2 positioned on the axis of the protective frame 4 is provided with a groove as an optical fiber placing groove 11, the opening direction of the optical fiber placing groove 11 is the same as the front face of the fan-shaped boss, the optical fiber placing groove penetrates through three areas of the fan-shaped boss, the cuboid and the fan-shaped boss along the axial direction of the special-shaped spring 2, the depth of the optical fiber groove and the length of the side length of the cuboid at the middle section are 1:2, the width of the optical fiber groove is 2mm, and.
4 through square holes are uniformly distributed in a cuboid region at the middle section of the special-shaped spring 2, the opening direction of each square hole is in the same direction as that of the optical fiber groove, the width direction of each square hole is set along the axial direction of the special-shaped spring 2, the aspect ratio of each square hole is 4:3, and the distance between the square holes is 8-10 mm.
The fan-shaped bosses on the two sides of the special-shaped spring 2 are respectively provided with two bolt fixing hole positions, the fan-shaped bosses on the two ends are inserted into the fixed cover plate 1 along the axial direction, and are fixedly connected with the fixed cover plate 1 and the protective frame 4 through the fixed connecting bolts 3.
The phase-shift grating 6 is placed in the fiber groove along the axis of the protection frame 4. Two ends of the phase shift grating 6 penetrate out of the central hole of the fixed cover plate 1.
The special-shaped spring 2 is of a plane symmetrical structure, a symmetrical plane A is located on a radial section where the middle point of the axis of the protective frame 4 is located, and a symmetrical plane B penetrates through the center of the circle of the section of the fan-shaped circular truncated cone and is perpendicular to the bottom surface of the optical fiber groove.
The maximum equivalent outer diameter of the special-shaped spring 2 is smaller than the inner diameter of the protective frame 4, and the two are not in contact.
The protective frame 4 is of a thick-wall cylindrical structure, the ratio of inner diameter to outer diameter is 1:2, n circular holes are axially and uniformly distributed in the cylinder wall of the protective frame 4, the diameter of each circular hole is 6mm, the hole interval is 8mm, and the circular holes are used as sound transmission windows.
Four bolt fixing holes are uniformly distributed on two sides of the protective frame 4 respectively.
A special-shaped spring 2 is inserted axially inside the protective frame 4, both of which are axially symmetrical about a central plane.
Further, in a possible realization, the material of the fixed cover plate 1, the shaped springs 2 and the protective frame 4 is invar. The selection principle of the materials is that on the premise of meeting the acoustic performance of the microphone, the microphone is high in rigidity and low in mass, and the first-order resonance frequency f1 of the microphone needing to be controlled in the design process is far greater than the working frequency band, namely f1The thermal expansion coefficient of the microphone structure is controlled to be close to that of the optical fiber material, usually the thermal expansion coefficient of the metal material is far higher than that of the optical fiber material, the processing difficulty of the fixed cover plate 1, the special-shaped spring 2 and the protective frame 4 is comprehensively considered, and finally the microphone structure is selected to be made of invar steel material.
Optionally, in a possible implementation manner of the present invention, the structural details at the front portion 5 of the shaped spring 2 have axial lengths a: b: a: c: d: d: d: d is 4:50: 4: 4: 3: 3: 3: 3.
wherein, the axial length of the fan-shaped boss of both sides is A, and the regional axial length of interlude cuboid is B, and the length and width that is located the quad slit in the regional interlude cuboid is C, D respectively.
Optionally, the thickness E and the diameter F of the fan-shaped boss satisfy the following proportional relationship:
E：F＝7：10。
optionally, the phase shift grating 6 is a fiber laser phase shift fiber grating.
Further, a pretightening force F is applied to two ends of the phase-shift grating 6.
Wherein E isfIs the elastic modulus, A, of the phase-shift grating 6fFor the cross-sectional area of the phase-shifted grating 6 grating, Δ λFFor the wavelength variation of the phase-shift grating 6, λFK is a constant and not less than 1 for the center wavelength of the phase shift grating 6.
Specifically, in the embodiment provided in the present application, a fiber laser microphone with a contour spring type sensitization structure, as shown in fig. 3, includes: the device comprises a pair of fixed cover plates 1, special-shaped springs 2, fixed connecting bolts 3, a protective frame 4, an armored optical cable 5 and a phase-shift grating 6. As shown in fig. 4, the special-shaped spring 2 is provided with an optical fiber groove 7, an optical fiber bonding point 8 and an optical fiber bonding point 9 in the axial direction, the phase-shift grating 6 is placed in the optical fiber groove 7 of the special-shaped spring 2, a certain tensile force F is applied to two ends of the phase-shift grating 6, the position of the grating area of the phase-shift grating 6 is adjusted between the fan-shaped boss 10 and the fan-shaped boss 11 of the special-shaped spring 2, and the phase-shift grating 6 is bonded to the optical fiber bonding points 7 and 8 by using 2011II type epoxy resin adhesive; as shown in fig. 3, after the shaped spring 2 penetrates into the protection frame 4, the tail fibers at two ends of the phase shift grating 6 penetrate through the through holes of the pair of fixed cover plates 1, and the fixed connection bolts 3 are used for fixedly connecting the pair of fixed cover plates 1 with the shaped spring 2 and the protection frame 4 respectively, so that the assembly of the fiber laser microphone structure is completed. The phase shift grating 6 is a fiber laser fiber grating.
Coating a GF-5 methylethyl 1:1 ratio polyurethane pouring sealant in the semi-cylindrical groove of the bottom mould, then placing the assembled special-shaped spring type optical fiber laser microphone structure in the semi-cylindrical groove of the bottom mould, pouring polyurethane glue into the special-shaped spring type optical fiber laser microphone structure and the semi-cylindrical groove of the top mould, then assembling and combining the top mould and the bottom mould, and completing the filling and sealing of the polyurethane glue body of the special-shaped spring type optical fiber laser microphone; and (3) supplementing polyurethane at the two through holes of the top die until a colloid bulge is formed on the upper surface of the die, and removing the top die and the bottom die after curing to obtain the special-shaped spring type optical fiber laser microphone.
Examples
The center of the special-shaped spring 2 is provided with an axial rectangular groove, two ends of the special-shaped spring are respectively provided with a fan-shaped boss, namely a left fan-shaped boss 10 and a right fan-shaped boss 11, and the axis of the fan-shaped boss is superposed with the axis of the protection frame 4. The profile spring 2 structure is inserted axially into the protective frame 4. The pair of fixed cover plates 1 are respectively arranged at two ends of the protective frame 4, the fan-shaped bosses at the outer sides of the special-shaped springs 2 are sequentially inserted into the central through holes of the fixed cover plates 1, and the fixed cover plates 1, the special-shaped springs 2 and the protective frame 4 are limited and fixed by the fixed connecting bolts 3; wherein, the inside of the protective frame 4, the special-shaped spring 2 and the fixed cover plate are filled with GF-5A, B and 1:1 proportion of polyurethane pouring sealant. The phase shift grating 6 is located at the axis position in the protective frame 4, and two ends of the phase shift grating 6 respectively penetrate out of the pair of fixed cover plates. Polyurethane pouring sealant is filled between the phase shift grating 6 and the fixed cover plate 1, and the phase shift grating 6 and the fixed cover plate 1 are not in direct contact.
The middle section structure of the special-shaped spring 2 is a cuboid; the cross section of the cuboid at the middle section of the special-shaped spring 2 is as follows: a square shape; the maximum equivalent diameters of the cross sections of the special-shaped springs are all smaller than the inner diameter of the protection frame 4; wherein the structure of the special-shaped spring 2 is not contacted with the invar alloy protective frame 4, and the special-shaped spring and the invar alloy protective frame are connected through the fixed cover plates 1 at two sides and the fixed connecting bolt 3.
A pair of fan-shaped circular truncated cone bulges are arranged at two ends of the outermost side of the special-shaped spring 2 made of invar alloy; wherein, the outer surface of the two outermost ends of the special-shaped spring 2 is: a step structure having a part-circular protrusion;
the special-shaped spring 2 is provided with an optical fiber groove along the axis direction and penetrates through the whole special-shaped spring 2 structure; the optical fiber groove is a groove with a rectangular cross section.
As shown in fig. 1, the special-shaped spring 2 is in a bilateral symmetry mode, the axial lengths of the fan-shaped bosses at the two sides are both a, the axial length of the cuboid region at the middle section is B, the length and the width of the square hole in the cuboid region at the middle section are C, D respectively, wherein the length A, B, C, D is set according to the ratio of 4:50:3: 3; as shown in FIG. 2, the length E, F of the middle section area of the shaped spring 2 is set at 1: 1.
In summary, the special-shaped spring type optical fiber laser microphone disclosed by the invention is simple in structure and packaging process, the fixed cover plate 1, the special-shaped spring 2 and the protection frame 4 can be produced in a machining mode, the manufacturing cost is low, the production period is short, the consistency is high, and large-batch packaging in a short period can be realized.
In the working process, after the fiber laser microphone is excited by sound waves, the protective frame 4 contracts radially, the special-shaped spring 2 can be extruded outwards to drive the special-shaped spring 2 to generate a telescopic effect, so that the fiber laser fiber grating in the fiber groove of the special-shaped spring 2 generates extension and contraction changes, the output wavelength of the grating is correspondingly changed, and sound wave signals can be obtained through back-end demodulation.
The special-shaped spring type optical fiber laser microphone adopts a special-shaped spring type acoustic sensing element, the material can be a metal material with higher elastic modulus, the elastic modulus can reach 70 GPa-200 GPa, polyurethane pouring sealant is filled in the special-shaped spring type optical fiber laser microphone, so that the resonance frequency of the optical fiber laser microphone is improved, and the special-shaped spring type optical fiber laser microphone can accurately measure signals in a wide frequency band.
Those skilled in the art will appreciate that the details of the invention not described in detail in the specification are within the skill of those skilled in the art.
Claims (6)
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116256053A (en) * | 2023-02-13 | 2023-06-13 | 中北大学 | Full-packaging high-temperature-resistant optical fiber noise sensor |
| CN118393763A (en) * | 2024-06-26 | 2024-07-26 | 中天科技精密材料有限公司 | Multi-core optical fiber and acousto-optic modulation device |
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| US20030021306A1 (en) * | 1998-12-04 | 2003-01-30 | Fernald Mark R. | Bragg grating-based laser |
| US20030127587A1 (en) * | 2001-12-21 | 2003-07-10 | Eric Udd | Fiber grating environmental sensing system |
| US20160209208A1 (en) * | 2015-01-20 | 2016-07-21 | Jinn Her Enterprise Co., Ltd. | Self-tensed and fully spring jacketed optical fiber sensing structure |
| US20160320555A1 (en) * | 2015-04-30 | 2016-11-03 | Jinn Her Enterprise Co., Ltd. | Thermal compensated and tensed spring compact fiber bragg grating wavelength filter device |
| CN108151865A (en) * | 2017-12-08 | 2018-06-12 | 北京航天控制仪器研究所 | A kind of bamboo joint type fiber laser hydrophone encapsulating structure and its assembly method |
| CN108174334A (en) * | 2017-12-28 | 2018-06-15 | 中国电子科技集团公司第三研究所 | A diaphragm-free fiber optic laser microphone |
| CN109813418A (en) * | 2019-03-18 | 2019-05-28 | 曲阜师范大学 | A one-dimensional fiber optic vector microphone probe |
| CN112113653A (en) * | 2020-04-30 | 2020-12-22 | 北京航天控制仪器研究所 | Folded beam type optical fiber laser hydrophone |
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| CN116256053A (en) * | 2023-02-13 | 2023-06-13 | 中北大学 | Full-packaging high-temperature-resistant optical fiber noise sensor |
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