CN216349082U - Sensing probe, optical fiber interference type hydrophone based on air cavity and monitoring system - Google Patents
Sensing probe, optical fiber interference type hydrophone based on air cavity and monitoring system Download PDFInfo
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- CN216349082U CN216349082U CN202122511842.1U CN202122511842U CN216349082U CN 216349082 U CN216349082 U CN 216349082U CN 202122511842 U CN202122511842 U CN 202122511842U CN 216349082 U CN216349082 U CN 216349082U
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Abstract
The utility model belongs to the field of underwater acoustic signal detection, and provides a sensing probe, an optical fiber interference type hydrophone based on an air cavity and a monitoring system. The sensing probe comprises a 1 multiplied by 2 coupler, a reference arm optical fiber, an elastic cylinder, a Faraday rotator mirror, a shell and a sensing optical fiber; the two branches of the 1 x 2 coupler are respectively connected with the reference arm optical fiber and the sensing optical fiber, the tail ends of the reference arm optical fiber and the sensing optical fiber are both connected with the Faraday rotator mirror, the sensing optical fiber is wound on one side of the elastic tube, the outer layer of the elastic tube is provided with the shell, and an air cavity is formed between the shell and the elastic tube.
Description
Technical Field
The utility model belongs to the field of underwater acoustic signal detection, and particularly relates to a sensing probe, an optical fiber interference type hydrophone based on an air cavity and a monitoring system.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The observation and measurement of sound waves in water have unique conditions, the penetration capacity of light in water is very limited, and people can only see objects within dozens of meters to dozens of meters even in the clearest seawater; electromagnetic waves also attenuate too quickly in water and the shorter the wavelength the greater the loss, even with high power, low frequency electromagnetic waves, which can only propagate for tens of meters. However, the attenuation of the sound wave propagating in water is much smaller, a bomb of several kilograms explodes in the deep sea sound channel, signals can be received in the range of twenty thousand kilometers, and the low-frequency sound wave can penetrate through the stratum of several kilometers on the sea bottom and obtain information in the stratum. The optical fiber hydrophone is a basic device for sound wave detection, and is a new underwater sound detection sensor, and gradually becomes the mainstream underwater sound sensor at present by virtue of the advantages of high sensitivity, strong anti-interference capability and the like. The optical fiber hydrophone based on the interference principle has the advantages of high sensitivity, strong noise suppression capability and the like, and becomes the current main research direction. In the present situation, some shaped samples of fiber optic hydrophones have been available for undersea experiments, but most of them are still in the laboratory research phase.
The existing interference type optical fiber hydrophone probe based on a differential structure adopts a hollow free overflow type structure with three layers of thin-walled cylinders nested, the optical fiber directly senses the change of underwater sound pressure to generate deformation, the sensitivity is low, and the structure manufacture is complex and difficult to realize. The existing interferometric fiber optic hydrophone with the reference interferometer can reduce the phase noise of low-frequency drift caused by the external environment, but the reference interferometer is needed, and the hydrophone is complex in manufacturing process, large in size and difficult to realize.
In summary, the inventors found that the conventional optical fiber hydrophone has the problems of low sensitivity, unstable response and complex manufacturing process.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problems in the background art, the utility model provides a sensing probe, an optical fiber interference hydrophone based on an air cavity and a monitoring system.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a first aspect of the utility model provides a sensing probe comprising a 1 x 2 coupler, a reference arm optical fiber, a resilient cylinder, a faraday rotator mirror, a housing and a sensing optical fiber; the two branches of the 1 x 2 coupler are respectively connected with the reference arm optical fiber and the sensing optical fiber, the tail ends of the reference arm optical fiber and the sensing optical fiber are both connected with the Faraday rotator mirror, the sensing optical fiber is wound on one side of the elastic tube, the outer layer of the elastic tube is provided with the shell, and an air cavity is formed between the shell and the elastic tube.
In one embodiment, the reference arm fiber and the 1 x 2 coupler are both fixed to an inner wall of the housing.
In one embodiment, a side wall of the housing is provided with a fiber hole.
In one embodiment, an optical fiber is inserted into the optical fiber hole, and the optical fiber is connected to the 1 × 2 coupler.
As an embodiment, a sealant is further disposed between the optical fiber hole and the optical fiber.
In one embodiment, the sensing fiber is a single mode fiber.
A second aspect of the utility model provides an air-cavity based fibre-optic interferometric hydrophone apparatus comprising a sensing probe as described above; the semiconductor laser, the optical fiber circulator, the photoelectric detection module and the signal analysis module are arranged on the optical fiber circulator;
the three ends of the optical fiber circulator are respectively connected with the semiconductor laser, the sensing probe and the photoelectric detection module; the photoelectric detection module is connected with the signal analysis module.
In one embodiment, the semiconductor laser is a narrow linewidth semiconductor laser.
In one embodiment, the signal analysis module is further connected to a display module, and the display module is configured to display the measured underwater sound pressure signal.
A third aspect of the utility model provides a monitoring system comprising an air cavity based fibre optic interferometric hydrophone apparatus as described above.
Compared with the prior art, the utility model has the beneficial effects that:
(1) the reference arm optical fiber and the 1 multiplied by 2 coupler are fixed in the shell, so that the stability of system measurement is improved, the sensing optical fiber and the reference optical fiber are in the same temperature and noise environment, the system noise is reduced, and the influence caused by temperature change is eliminated.
(2) The sensing probe adopts an external air cavity structure, the optical fiber is not contacted with external water, a protective layer is not required to be coated on the outer layer of the optical fiber, the influence of a protective layer material on the deformation of the elastic tube is eliminated, the sensitivity of system response is improved, meanwhile, the corrosion of external seawater on the optical fiber is avoided, and the service lives of the sensing probe and the hydrophone with the sensing probe are prolonged.
(3) The utility model uses the elastic cylinder as the sensitive material, the shell plays the role of protecting and fixing the optical fiber, and forms the air cavity structure, the problem that the reference optical fiber and the sensing optical fiber have the same environment is realized by using a simple structure, the cost is low, and the volume, the manufacturing process and the cost of the optical fiber hydrophone are effectively reduced.
Advantages of additional aspects of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the utility model, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the utility model and together with the description serve to explain the utility model and not to limit the utility model.
FIG. 1 is a schematic structural diagram of a sensing probe according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an optical fiber interferometric hydrophone apparatus based on an air cavity in accordance with an embodiment of the present invention.
The device comprises a semiconductor laser 1, a semiconductor laser 2, an optical fiber circulator 3, a 1 x 2 coupler 4, a reference arm optical fiber 5, a Faraday rotator mirror 6, an elastic cylinder 7, a shell 8, a sensing optical fiber 9, an optical fiber hole 10, an air cavity 11, a photoelectric detection module 12 and a signal analysis module.
Detailed Description
The utility model is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the utility model as claimed. 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 invention 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 utility model. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
Example one
As shown in fig. 1, the present embodiment provides a sensing probe, which includes a 1 × 2 coupler 3, a reference arm fiber 4, an elastic tube 6, a faraday rotator mirror 5, a housing 7, and a sensing fiber 8; two branches of the 1 x 2 coupler 3 are respectively connected with the reference arm optical fiber 4 and the sensing optical fiber 8, the tail ends of the reference arm optical fiber 4 and the sensing optical fiber 8 are both connected with the Faraday rotator mirror 5, the sensing optical fiber 8 is wound on one side of the elastic tube 6, the outer layer of the elastic tube 6 is provided with the shell 7, and an air cavity is formed between the shell 7 and the elastic tube 6.
Wherein, the sensing fiber 8 is a single mode fiber.
In a specific implementation, the reference arm fiber 4 and the 1 × 2 coupler 3 are both fixed on the inner wall of the housing 7.
It should be noted that the fixing manner can be an adhesive fixing manner or other existing fixing manners, and those skilled in the art can set the fixing manner according to actual specific situations, which are not described in detail herein.
The reference arm optical fiber 4 and the 1 × 2 coupler 2 of the embodiment are fixed in the sensing probe, so that the stability of system measurement is improved, the sensing optical fiber and the reference optical fiber are in the same temperature and noise environment, the system noise is reduced, and the influence caused by temperature change is eliminated.
In the specific implementation, a side wall of the housing 7 is provided with a fiber hole 9. And an optical fiber is arranged in the optical fiber hole 9 in a penetrating manner and is connected with the 1 x 2 coupler 3.
In order to prevent external water from entering and forming a strict air cavity structure, a sealant is further arranged between the optical fiber hole 9 and the optical fiber.
Example two
Referring to fig. 2, the present embodiment provides an air-cavity-based fiber optic interferometric hydrophone apparatus, comprising a sensing probe as described above; the semiconductor laser 1, the optical fiber circulator 2, the photoelectric detection module 11 and the signal analysis module 12; the three ends of the optical fiber circulator 2 are respectively connected with the semiconductor laser 1, the sensing probe and the photoelectric detection module 11; the photodetection module 11 is connected to the signal analysis module 12.
The working principle of the photoelectric detection module 11 is based on the photoelectric effect, and the thermal detector changes its electrical properties based on the temperature rise after the material absorbs the optical radiation energy. The photodetection module 11 is of an existing structure, for example, an InGaAs photodetection module is adopted, and those skilled in the art can select a corresponding model according to actual accuracy requirements.
The signal analysis module 12 may adopt a DSP processor chip, and the specific model thereof may be selected according to the actual precision requirement.
And the signal analysis module demodulates the corresponding measured underwater sound pressure signal from the interference signal.
It should be further noted that the process of demodulating the corresponding measured underwater sound pressure signal from the interference signal by the signal analysis module 12 belongs to the prior art, and is demodulated by using the existing program.
In one embodiment, the semiconductor laser 1 is a narrow linewidth semiconductor laser.
For example: the wavelength of the semiconductor laser 1 can be selected from 1550nm, 1310nm, etc., and those skilled in the art can specifically select the wavelength according to actual situations.
In one or more embodiments, the signal analysis module 12 is further connected to a display module, and the display module is configured to display the measured underwater sound pressure signal.
Laser light emitted by the semiconductor laser 1 enters the 1 x 2 coupler 3 through the optical fiber circulator 2 and is divided into two beams of light, the two beams of light respectively enter the Faraday rotary mirror 5 at the tail ends of the sensing optical fiber and the reference optical fiber, the two beams of light are reflected on the Faraday rotary mirror, and the two beams of light reflected back to the original optical path enter the 1 x 2 coupler 3 again to generate an interference phenomenon. When the optical fiber hydrophone is placed in water, the inner side of the elastic cylinder 6 is water, and the outer side of the elastic cylinder is air. Under the action of the underwater sound pressure, the elastic tube 6 deforms in the radial direction, so that the length of the optical fiber wound on the elastic tube is changed, and the length of the optical fiber 4 of the reference arm is fixed, so that the corresponding optical path difference is generated between two paths of reflected light, and interference fringes are generated. Coherent light coming out of the 1 multiplied by 2 coupler 3 enters the optical fiber circulator 2, the other end of the optical fiber circulator 2 is connected to the photoelectric detection module 11, an optical signal is converted into an electric signal, corresponding phase change of interference fringes can be detected, and then the signal analysis module 12 demodulates the electric signal to obtain a corresponding measured underwater sound pressure signal. Because the light in the sensing arm is reflected back through the Faraday rotator mirror in the original path, the optical path difference caused by the underwater sound pressure effect is doubled, and the sensitivity is doubled.
The reference arm optical fiber 4, the Faraday rotator mirror 5 and the 1 multiplied by 2 coupler 3 of the embodiment are fixed on the inner wall of the protective shell 7, so that the reference arm and the sensing arm are in the same temperature and environmental noise, the influence of temperature change and environmental disturbance on a system is eliminated, the noise is reduced, meanwhile, the non-sensing optical fiber parts in the two arms of the interferometer are fixed and are not influenced by external disturbance, and the response stability of the system is improved. And the optical fiber hydrophone is simple and uncomplicated in structure, is easy to realize, and effectively reduces the volume, the manufacturing process and the cost of the optical fiber hydrophone.
The optical fiber hydrophone of the embodiment adopts an outer air cavity structure, optical fibers are not in contact with external water, a protective layer is not required to be coated on the outer layer of the optical fibers, the influence of the protective layer material on the deformation of the elastic tube is eliminated, the sensitivity of system response is improved, meanwhile, the corrosion of external seawater to the optical fibers is avoided, and the service life of the hydrophone is prolonged.
The utility model discloses an utilize the elastic tube as sensitive material, the protective housing plays the effect of protection and fixed optic fibre to form air cavity structure, utilized simple structure to realize reference optic fibre and sensing optic fibre with the problem of environment, it is with low costs, reduced optic fibre hydrophone's volume, manufacturing process and cost effectively.
EXAMPLE III
This embodiment provides a monitoring system comprising an air cavity based fiber optic interferometric hydrophone assembly as described in embodiment two above.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A sensing probe is characterized by comprising a 1 x 2 coupler, a reference arm optical fiber, an elastic cylinder, a Faraday rotator mirror, a shell and a sensing optical fiber; the two branches of the 1 x 2 coupler are respectively connected with the reference arm optical fiber and the sensing optical fiber, the tail ends of the reference arm optical fiber and the sensing optical fiber are both connected with the Faraday rotator mirror, the sensing optical fiber is wound on one side of the elastic tube, the outer layer of the elastic tube is provided with the shell, and an air cavity is formed between the shell and the elastic tube.
2. The sensing probe of claim 1, wherein the reference arm fiber and the 1 x 2 coupler are each secured to an inner wall of the housing.
3. The sensing probe of claim 1, wherein a side wall of the housing is provided with a fiber aperture.
4. The sensing probe of claim 3, wherein an optical fiber is threaded into the fiber hole, the optical fiber being connected to the 1 x 2 coupler.
5. The sensing probe of claim 4, wherein a sealant is disposed between the optical fiber bore and the optical fiber.
6. The sensing probe of claim 1, wherein the sensing fiber is a single mode fiber.
7. An air cavity based fiber optic interferometric hydrophone assembly comprising the sensing probe of any one of claims 1-6; the semiconductor laser, the optical fiber circulator, the photoelectric detection module and the signal analysis module are arranged on the optical fiber circulator;
the three ends of the optical fiber circulator are respectively connected with the semiconductor laser, the sensing probe and the photoelectric detection module; the photoelectric detection module is connected with the signal analysis module.
8. The air cavity based fiber optic interferometric hydrophone apparatus of claim 7, wherein the semiconductor laser is a narrow linewidth semiconductor laser.
9. The air cavity-based fiber optic interferometric hydrophone apparatus of claim 7, wherein the signal analysis module is further coupled to a display module, the display module configured to display the measured underwater acoustic pressure signal.
10. A monitoring system comprising an air cavity based fiber optic interferometric hydrophone apparatus of any of claims 7-9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122511842.1U CN216349082U (en) | 2021-10-18 | 2021-10-18 | Sensing probe, optical fiber interference type hydrophone based on air cavity and monitoring system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202122511842.1U CN216349082U (en) | 2021-10-18 | 2021-10-18 | Sensing probe, optical fiber interference type hydrophone based on air cavity and monitoring system |
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| CN216349082U true CN216349082U (en) | 2022-04-19 |
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| CN202122511842.1U Active CN216349082U (en) | 2021-10-18 | 2021-10-18 | Sensing probe, optical fiber interference type hydrophone based on air cavity and monitoring system |
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