A fiber optic hydrophone probe with a sensitizing structure

Abstract

The application discloses a fiber hydrophone probe with a sensitizing structure, which comprises an elastic inner fiber supporting thin-walled cylinder, an outer fiber supporting thin-walled cylinder, a protective sleeve, an outer cylinder sleeve, a fixing ring, an inner annular baffle, an outer annular baffle, an inner fiber layer, an outer fiber layer, a sound transmission hole and an air cavity. When the hydrophone probe is placed in water, the material parameters and the structural parameters of the inner and outer fiber supporting thin-walled cylinders are different. The inner fiber supporting thin-walled cylinder is made of an elastic body, has a small cylinder wall thickness and a large hardness. When the underwater sound acts on the outer fiber thin-walled cylinder, the outer fiber thin-walled cylinder is not affected, so the outer fiber changes little. When the underwater sound acts on the inner surface of the inner fiber thin-walled cylinder, the inner fiber thin-walled cylinder is easy to deform, so the length of the inner fiber layer changes, thus the optical phase difference is generated, the sound pressure sensitivity of the hydrophone is calculated.

Description

Technical Field

[0001] This invention belongs to the field of acoustic wave detection technology, specifically, it relates to a fiber optic hydrophone probe with an enhanced sensitivity structure. Background Technology

[0002] Fiber optic hydrophones are a new type of underwater acoustic sensor built on fiber optic and optoelectronic technologies, using fiber optics as the sensing medium for underwater acoustic signals. Sonar systems composed of fiber optic hydrophones can be applied to towed systems of submarines or surface ships, as well as to shore-based early warning systems, serving as an advanced detection method for modern naval anti-submarine warfare and underwater weapon testing. Measuring underwater noise fields with fiber optic hydrophones allows for the study of sound propagation in the marine acoustic environment, ocean noise, seabed acoustic characteristics, and target acoustic characteristics, injecting vitality into the development of marine acoustics. Fiber optic hydrophones can also be applied to offshore oil and gas exploration. Therefore, fiber optic hydrophones have become an important direction in the development of modern fiber optic sensing technology and a major direction in the development of underwater acoustic sensing technology.

[0003] Chinese invention patent application CN201811104270.1 discloses a fiber optic hydrophone probe packaging structure, including a housing with a top opening. A fiber optic hydrophone probe is fixed inside the housing, and a liquid medium (an inert liquid) fills the space between the probe and the inner wall of the housing. The liquid surface is sealed by a thin film, and a sealing structure is cast at the opening of the housing. The packaging method includes the following steps: casting the top-opening housing with a packaging material and allowing the housing to solidify; fixing the fiber optic hydrophone probe inside the housing; filling the housing with an inert liquid, submerging the probe; sealing the liquid surface with a thin film; and casting the packaging structure at the opening of the housing with the packaging material. This packaging structure not only effectively improves the reliability of the fiber optic hydrophone probe but also reduces the risk of probe damage.

[0004] The drawback of existing patents is that while sealing the surface of the inert liquid with a thin film and casting the encapsulation structure with encapsulation material at the opening of the shell achieves good sealing, the preparation process of the inert liquid is complex, the preparation equipment is expensive, and the thin film is difficult to repair if it breaks, requiring the replacement of a new hydrophone. Current hydrophone probes with air cavity structures are complex in structure and have low sensitivity. Summary of the Invention

[0005] To address the issues of high cost of existing thin-film sealed inert liquid hydrophones and the complex structure and low sensitivity of hydrophone probes with air cavity structures, this invention provides a fiber optic hydrophone probe with an enhanced sensitivity structure.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A fiber optic hydrophone probe with a sensitivity-enhancing structure includes an inner fiber optic support thin-walled cylinder, an outer fiber optic support thin-walled cylinder, a protective sleeve, an outer sleeve, a fixing ring, an inner annular baffle, an outer annular baffle, an inner fiber optic layer, an outer fiber optic layer, a sound-transmitting hole, and an air cavity. The outer annular baffle includes an outer annular baffle A for fixing both ends of the outer fiber optic support thin-walled cylinder and an outer annular baffle B for fixing in the middle.

[0008] The entire fiber optic hydrophone probe consists of an inner fiber optic support thin-walled cylinder, an outer fiber optic support thin-walled cylinder, and a protective sleeve, arranged sequentially from the inside out. The two ends of the inner fiber optic support thin-walled cylinder are respectively connected to the inner annular baffle with an interference fit. The middle of the outer fiber optic support thin-walled cylinder is connected to the outer annular baffle B via an interference fit. The two ends of the outer fiber optic support thin-walled cylinder are tightly connected to the outer annular baffle A via an interference fit. The two sides of the inner annular baffle at both ends of the inner fiber optic support thin-walled cylinder are secured to the inner side of the outer annular baffle A. The outer sleeve is connected to the outer side of the outer annular baffle B and is fixed to the inner surface of the protective sleeve. Fixing rings are connected to both ends of the protective sleeve. The inner fiber layer is spirally wound around the inner fiber optic support thin-walled cylinder, and the outer fiber layer is spirally wound around the outer fiber optic support thin-walled cylinder.

[0009] Furthermore, the inner optical fiber thin-walled tube is made of polysulfone material.

[0010] Furthermore, the cross-section of the inner fiber thin-walled tube is square.

[0011] Furthermore, the outer optical fiber thin-walled tube is made of stainless steel.

[0012] Furthermore, the inner and outer fiber optic thin-walled tubes are connected to annular baffles at both ends and are connected through the annular baffles; an air cavity is formed between the two thin-walled tubes.

[0013] Furthermore, the protective sleeve has several sound-permeable holes.

[0014] Furthermore, the inner fiber-supported thin-walled cylinder adopts a hollow structure.

[0015] Furthermore, the inner fiber layer and the outer fiber layer use the same material and size parameters, and both the inner fiber support thin-walled cylinder and the outer fiber support thin-walled cylinder are wound with two layers of optical fibers.

[0016] Furthermore, the outer annular baffle A and the inner annular baffle are tightly connected on both sides, and the gaps are filled with epoxy resin.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] By eliminating the thin-film structure, the cross-section of the inner fiber-supported thin-walled cylinder is square, which makes the structure stable and less prone to damage. At the same time, the entire fiber optic hydrophone probe structure is simplified and has high sound pressure sensitivity.

[0019] Using the outer fiber layer as the reference arm and the inner fiber layer as the sensing arm can more effectively eliminate the effects of noise.

[0020] A thin-walled tube with an inner fiber optic support, constructed using polysulfone material with a square cross-section, is used to improve the sensitivity of the hydrophone.

[0021] Fix both ends of the inner fiber support thin-walled cylinder to eliminate the fixing ring located in the middle of the inner fiber support thin-walled cylinder in order to improve the acoustic pressure sensitivity of the hydrophone probe.

[0022] An air cavity is formed between the inner fiber-supported thin-walled cylinder and the outer fiber-supported thin-walled cylinder, which can improve the sound pressure sensitivity.

[0023] The inner fiber optic support thin-walled cylinder uses a hollow structure. Water pressure and sound pressure are applied to the inner surface of the inner fiber optic support thin-walled cylinder and the outer surface of the outer fiber optic support thin-walled cylinder to ensure that the light intensity input to both arms is the same and to balance the water pressure.

[0024] The protective sleeve has several sound-permeable holes on the outer sleeve so that sound pressure and water pressure can be applied to the thin-walled cylinder wall of the outer optical fiber support. Attached Figure Description

[0025] Figure 1 A schematic diagram of the overall structure of a fiber optic hydrophone probe with a sensitivity-enhancing structure;

[0026] Figure 2 A schematic diagram of an explosion of a fiber optic hydrophone with a sensitivity-enhancing structure;

[0027] Figure 3 Schematic diagram of a thin-walled cylinder structure supported by internal optical fibers;

[0028] Figure 4 This is a schematic diagram of a thin-walled cylinder structure supported by external optical fibers.

[0029] The markings in the diagram are as follows: 1-Inner fiber support thin-walled cylinder, 2-Outer fiber support thin-walled cylinder, 3-Protective sleeve, 4-Outer sleeve, 5-Fixing ring, 6-Inner annular baffle, 701-Outer annular baffle A, 702-Outer annular baffle B, 8-Inner fiber layer, 9-Outer fiber layer, 10-Sound transmission hole, 11-Air cavity. Detailed Implementation

[0030] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0031] like Figure 1 , 2As shown in Figures 3 and 4, this embodiment provides a fiber optic hydrophone probe with a sensitivity-enhancing structure, including an inner fiber support thin-walled cylinder 1, an outer fiber support thin-walled cylinder 2, a protective sleeve 3, an outer sleeve 4, a fixing ring 5, an inner annular baffle 6, an outer annular baffle, an inner fiber layer 8, an outer fiber layer 9, a sound-transmitting hole 10, and an air cavity 11. The outer annular baffle includes an outer annular baffle A701 for fixing both ends of the outer fiber support thin-walled cylinder 2 and an outer annular baffle B702 for fixing in the middle.

[0032] The entire fiber optic hydrophone probe consists of an inner fiber optic support thin-walled cylinder 1, an outer fiber optic support thin-walled cylinder 2, and a protective sleeve 3, arranged sequentially from the inside out. The two ends of the inner fiber optic support thin-walled cylinder 1 are respectively connected to the inner annular baffle 6 by interference fit. The middle of the outer fiber optic support thin-walled cylinder 2 is connected to the outer annular baffle B702 by interference fit. The two ends of the outer fiber optic support thin-walled cylinder 2 are tightly connected to the outer annular baffle A701 by interference fit. The two sides of the inner annular baffle 6 at both ends of the inner fiber optic support thin-walled cylinder 1 are locked inside the outer annular baffle A701. The outer sleeve 4 is connected to the outer side of the outer annular baffle B702. The outer sleeve 4 is fixed to the inner surface of the protective sleeve 3. The two ends of the protective sleeve 3 are connected to fixing rings 5. The inner fiber layer 8 is spirally wound on the inner fiber optic support thin-walled cylinder 1, and the outer fiber layer 9 is spirally wound on the outer fiber optic support thin-walled cylinder 2.

[0033] The inner fiber thin-walled tube is made of polysulfone material. The fiber layer wound on the inner fiber thin-walled tube deforms by sensing sound pressure, and the fiber length changes, thus generating optical phase.

[0034] The inner fiber optic thin-walled tube has a square cross-section. Compared with a circular cross-section, the square cross-section of the inner fiber optic thin-walled tube effectively improves the acoustic pressure sensitivity of the hydrophone probe without changing the acceleration sensitivity.

[0035] The outer fiber optic thin-walled tube is made of stainless steel. Its high hardness makes it less affected by sound pressure levels, and it serves as a reference arm to generate optical phase.

[0036] Both ends of the inner and outer fiber optic thin-walled tubes are connected to annular baffles and are linked together by the annular baffles; an air cavity 11 is formed between the two thin-walled tubes. This ensures the airtightness of the entire hydrophone.

[0037] The protective sleeve 3 has several sound-permeable holes 10 to allow sound pressure and water pressure to be applied to the wall of the outer optical fiber support thin-walled cylinder 2.

[0038] The inner fiber-supported thin-walled cylinder 1 adopts a hollow structure. Sound pressure is applied to the inner surface of the inner fiber-supported thin-walled cylinder 1.

[0039] The inner fiber layer 8 and the outer fiber layer 9 use the same material and size parameters, and two layers of optical fibers are wound on both the inner fiber support thin-walled cylinder 1 and the outer fiber support thin-walled cylinder 2.

[0040] The outer annular baffle A701 and the inner annular baffle 6 are tightly connected on both sides, and the gaps are filled with epoxy resin. This ensures the axial fixation of the two optical fibers supporting the thin-walled cylinder, achieving a seal.

[0041] The principle of this invention is that when the hydrophone probe is placed in water, a structure is formed: water—outer fiber layer 9—outer fiber thin-walled tube—inner fiber layer 8—inner fiber thin-walled tube—water, where the outer side of the outer fiber layer 9 is water and the outer side of the inner fiber layer 8 is air. The material and structural parameters of the inner and outer fiber supporting thin-walled tubes 2 are different. The inner fiber supporting thin-walled tube 1 is an elastic body with a small wall thickness, while the outer fiber supporting thin-walled tube 2 has a larger wall thickness and greater rigidity. When underwater sound acts on the outer fiber thin-walled tube, the outer fiber thin-walled tube is unaffected, so the outer fiber does not change significantly. When underwater sound acts on the inner surface of the inner fiber thin-walled tube, the inner fiber thin-walled tube is prone to deformation, thus changing the length of the inner fiber layer 8. Since the inner and outer fiber layers 9 act on the sensing arm and reference arm of the hydrophone interferometer, respectively, an optical phase difference can be generated, allowing the calculation of the hydrophone's sound pressure sensitivity.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] By eliminating the thin-film structure, the cross-section of the inner fiber-supported thin-walled cylinder is square, which makes the structure stable and less prone to damage. At the same time, the entire fiber optic hydrophone probe structure is simplified and has high sound pressure sensitivity.

[0044] Using the outer fiber layer 9 as the reference arm and the inner fiber layer 8 as the sensing arm can more effectively eliminate the influence of noise.

[0045] A thin-walled cylinder with an inner fiber optic support 1, constructed with polysulfone material in a square cross section, is used to improve the sensitivity of the hydrophone.

[0046] Fix both ends of the inner fiber support thin-walled cylinder 1 and eliminate the fixing ring 5 located in the middle of the inner fiber support thin-walled cylinder 1 to improve the acoustic pressure sensitivity of the hydrophone probe.

[0047] An air cavity 11 is formed between the inner fiber-supported thin-walled cylinder 1 and the outer fiber-supported thin-walled cylinder 2, which can improve the sound pressure sensitivity.

[0048] The inner fiber support thin-walled cylinder 1 uses a hollow structure. Water pressure and sound pressure are applied to the inner surface of the inner fiber support thin-walled cylinder 1 and the outer surface of the outer fiber support thin-walled cylinder 2 to ensure that the light intensity input to the two arms is the same and to balance the water pressure.

[0049] The protective sleeve 3 has several sound-permeable holes 10 on the outer sleeve 4 so that sound pressure and water pressure can be applied to the wall of the outer optical fiber support thin-walled cylinder 2.

[0050] The above provides a detailed description of a fiber optic hydrophone probe with an enhanced sensitivity structure provided in this application. The specific embodiments described are merely for the purpose of helping to understand the structure and design of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles thereof, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A fiber optic hydrophone probe with a sensitivity-enhancing structure, characterized in that, It includes an elastic body fiber support thin-walled cylinder (1), an outer fiber support thin-walled cylinder (2), a protective sleeve (3), an outer sleeve (4), a fixing ring (5), an inner annular baffle (6), an outer annular baffle, an inner fiber layer (8), an outer fiber layer (9), a sound-transmitting hole (10), and an air cavity (11). The outer annular baffle includes an outer annular baffle A (701) for fixing the two ends of the outer fiber support thin-walled cylinder (2) and an outer annular baffle B (702) for fixing in the middle. The entire fiber optic hydrophone probe is arranged from the inside out as follows: inner fiber support thin-walled cylinder (1), outer fiber support thin-walled cylinder (2), and protective sleeve (3). The two ends of the inner fiber support thin-walled cylinder (1) are respectively connected to the inner annular baffle (6) by interference fit. The middle of the outer fiber support thin-walled cylinder (2) is connected to the outer annular baffle B (702) by interference fit. The two ends of the outer fiber support thin-walled cylinder (2) are tightly connected to the outer annular baffle A (701) by interference fit. The two sides of the inner annular baffle (6) at both ends of the inner fiber support thin-walled cylinder (1) are stuck inside the outer annular baffle A (701). The outer sleeve (4) is connected to the outer side of the outer annular baffle B (702). The outer sleeve (4) is fixed to the inner surface of the protective sleeve (3). The two ends of the protective sleeve (3) are connected to the fixing ring (5). The inner fiber layer (8) is spirally wound on the inner fiber support thin-walled cylinder (1), and the outer fiber layer (9) is spirally wound on the outer fiber support thin-walled cylinder (2). The inner fiber support thin-walled cylinder (1) has a hollow structure and a square cross-section; an air cavity (11) is formed between the inner fiber support thin-walled cylinder (1) and the outer fiber support thin-walled cylinder (2); the sound-permeable hole (10) is provided on the protective sleeve (3); The outer annular baffle A (701) and the inner annular baffle (6) are tightly connected on both sides, and the gap is filled with epoxy resin.

2. The fiber optic hydrophone probe with a sensitivity-enhancing structure according to claim 1, characterized in that, The inner fiber-supported thin-walled cylinder is made of polysulfone material.

3. The fiber optic hydrophone probe with a sensitivity-enhancing structure according to claim 2, characterized in that, The outer fiber optic support thin-walled cylinder is made of stainless steel.

4. The fiber optic hydrophone probe with a sensitivity-enhancing structure according to claim 3, characterized in that, The protective sleeve (3) has several sound-permeable holes (10).

5. The fiber optic hydrophone probe with a sensitivity-enhancing structure according to claim 4, characterized in that, The inner fiber layer (8) and the outer fiber layer (9) use the same material and size parameters, and two layers of optical fibers are wound on both the inner fiber support thin-walled cylinder (1) and the outer fiber support thin-walled cylinder (2).

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