CN114623913A - Fiber grating hydrophone adopting cymbal-shaped diaphragm and tensile coating - Google Patents

Abstract

The invention relates to an optical fiber grating hydrophone adopting a cymbal-shaped diaphragm and a tensile coating, and belongs to the technical field of optical fiber hydrophones. The outer side of the supporting cylinder is covered with a sound-transmitting rubber sleeve, the left and right casings are respectively fixed on both sides of the supporting cylinder, and the left and right cymbal-shaped diaphragms are symmetrically and fixedly installed inside the supporting cylinder. The copper sheet and the right copper sheet are used to fix the fiber grating. The left and right tensile coatings are respectively coated on both sides of the grating region on the optical fiber. The fiber grating passes through the hole on the central axis of the hydrophone. The advantages are: using the diaphragm to convert the volume change of the oil cavity caused by the sound pressure into the length change of the fiber grating, the structure is simple; using the tensile coating, the deformation on the fiber grating is concentrated in the grating area to achieve the purpose of sensitization; The structure of the cymbal-shaped diaphragm and the support cylinder is fixed, which makes the hydrophone more stable and reliable.

Description

A Fiber Bragg Grating Hydrophone Using Cymbal Diaphragm and Tensile Coating

technical field

The invention belongs to the technical field of optical fiber hydrophones, and in particular relates to a fiber grating hydrophone using a cymbal-shaped diaphragm and a tensile coating.

Background technique

Sound waves are the only form of energy known to man that can travel long distances in seawater. A hydrophone is a type of sensor used to detect underwater sound waves for navigation, measurement and communication. Traditional hydrophones can be divided into electric type, capacitive type, piezoelectric type and so on according to the principle of detecting underwater acoustic signals.

In recent years, with the rapid development of fiber light source, fiber spectrometer and fiber grating processing technology, fiber grating hydrophone with high performance, miniaturization and high stability is gradually called a new generation of underwater acoustic detection sensor. Fiber grating hydrophones using fiber grating as the sensing source have received extensive attention from domestic and foreign scientific research institutions and scholars in the fields of national defense, military, and detection, and related technologies have achieved unprecedented development. Compared with other types of hydrophones, fiber grating hydrophones have the advantages of low noise, high sensitivity, large dynamic range, and excellent reliability. The packaged optical fibers are used as connectors, which are very suitable for forming large-scale hydrophones. Arrays and fiber optic hydrophones have been used by many countries as key R&D investment in national defense technology equipment.

The fiber grating sensor realizes the sensing function by using the optical waveguide characteristics of the optical fiber and the grating to reflect specific wavelengths and has the modulation effect of sensing specific parameters in the environment. sound signal. Compared with traditional piezoelectric hydrophones, fiber-optic hydrophones mainly have the following advantages: wide frequency band, high sensitivity, no electromagnetic interference, small mass, small volume and simple structure, combined with fiber-optic light source and fiber-optic spectrometer, can be integrated It has great application prospects.

At present, improving the pressure sensitivity of FBG hydrophones, using filtering structure to constrain the working frequency range of FBG hydrophones, and improving the structure to adapt to specific applications are the current development directions of FBG hydrophones. How to solve the problem of large acceleration response and high low-frequency noise is an important technical problem existing in fiber optic hydrophones, which needs to be further explored and improved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to increase the reliability and stability of the fiber grating hydrophone during operation by introducing the cymbal-shaped diaphragm and the way that the diaphragm is fixedly connected to the main structure, increase the tensile coating structure, and increase the optical fiber The sensitivity of the grating hydrophone to sound pressure.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

The outer side of the supporting cylinder (9) is covered with a sound-transmitting rubber sleeve (3), the two sides of the supporting cylinder (9) are respectively fixed to the left casing (1) and the right casing (5), and the supporting cylinder (9) is symmetrically fixed inside The left cymbal-shaped diaphragm (201) and the right cymbal-shaped diaphragm (401), the left copper plate (202) and the right copper plate (402) are installed on the diaphragms for fixing the fiber grating (7), the grid area on the optical fiber The left tensile coating (8) and the right tensile coating (6) are respectively coated on both sides, and the fiber grating (7) passes through the hole on the central axis of the hydrophone; the position where the fiber grating (7) contacts the hydrophone Sealing material is filled in the gaps of the left casing (1), the supporting cylinder (9) and the left cymbal-shaped diaphragm (201) to form a closed cavity; the right casing (5) is formed with the supporting cylinder (9) and the right cymbal-shaped diaphragm (201). The diaphragm (401) forms a closed cavity; the left cymbal-shaped diaphragm (201), the right cymbal-shaped diaphragm (401), the support cylinder (9) and the sound-transmitting rubber sleeve (3) form an oil cavity, which is filled with oil ; There are holes on the upper and lower sides of the middle of the support cylinder (9) for transmitting the sound pressure in the water.

The advantages of the invention are that: the volume change of the oil cavity caused by the sound pressure is converted into the length change of the fiber grating by using the diaphragm, and the structure is simple; Purpose: Adopt the structure that the cymbal-shaped diaphragm and the supporting cylinder are fixed to make the hydrophone more stable and reliable.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is a side sectional view of the central axis of the present invention.

Detailed ways

1 and 2, the present embodiment is described in detail. The fiber grating hydrophone described in the present embodiment adopts a cymbal-shaped diaphragm and a tensile coating. The outer side of the support cylinder 9 is covered with a sound-transmitting rubber sleeve 3, The two sides of the supporting cylinder 9 are respectively fixed to the left casing 1 and the right casing 5, and the left cymbal diaphragm 201 and the right cymbal diaphragm 401 are symmetrically fixed inside the supporting cylinder 9, and the left copper sheet 202 and the right cymbal diaphragm are installed on the diaphragm. The copper sheet 402 is used to fix the fiber grating 7, the left tensile coating 8 and the right tensile coating 6 are respectively coated on both sides of the grating area on the optical fiber, and the fiber grating 7 passes through the hole on the central axis of the hydrophone; the fiber grating 7. The gaps in contact with the hydrophone are filled with sealing materials; the left casing 1, the supporting cylinder 9 and the left cymbal-shaped diaphragm 201 form a closed cavity; the right casing 5, the supporting cylinder 9 and the right cymbal-shaped diaphragm 401 A closed cavity is formed; the left cymbal-shaped diaphragm 201, the right cymbal-shaped diaphragm 401, the supporting cylinder 9 and the sound-transmitting rubber sleeve 3 form an oil cavity, and the interior is filled with oil; to transmit sound pressure in water.

The working principle of the fiber grating hydrophone in the present invention is as follows: when the hydrophone receives the sound pressure of water underwater, the sound pressure will act on the oil in the oil cavity through the sound-transmitting rubber sleeve 3, and the oil will be absorbed by the water. Squeeze and transmit the pressure to the left cymbal diaphragm 201 and the right cymbal diaphragm 401 fixed on the support cylinder 7, the left cymbal diaphragm 201 and the right cymbal diaphragm 401 undergo axial deformation, and The deformation is transmitted to the fiber grating 7 fixed between the left copper sheet 202 and the right copper sheet 402. When the fiber grating 7 is axially deformed, most of the axial deformation will be concentrated in the grid region due to the existence of the tensile coating. , to increase the sensitivity of the fiber optic hydrophone to underwater sound pressure, and the wavelength of the reflected light will change. By measuring the wavelength reflected in the fiber grating 7, the corresponding underwater sound information can be obtained.

Claims (1)

1. A fiber grating hydrophone using a cymbal-shaped diaphragm and a tensile coating, comprising: a left housing (1), a left cymbal-shaped diaphragm (201), a left copper sheet (202), a sound-transmitting rubber sleeve (3), right cymbal diaphragm (401), right copper sheet (402), right casing (5), right tensile coating (6), fiber grating (7), left tensile coating (8), The supporting cylinder (9) is characterized in that: the outer side of the supporting cylinder (9) is covered with a sound-transmitting rubber sleeve (3), and the two sides of the supporting cylinder (9) are respectively fixed to the left casing (1) and the right casing (5) , the left cymbal-shaped diaphragm (201) and the right cymbal-shaped diaphragm (401) are symmetrically fixed inside the support cylinder (9), and the left copper plate (202) and the right copper plate (402) are installed on the diaphragm for fixing a fiber grating (7), the left tensile coating (8) and the right tensile coating (6) are respectively coated on both sides of the grating region on the optical fiber, and the fiber grating (7) passes through the hole on the central axis of the hydrophone; The gap between the fiber grating (7) and the hydrophone is filled with sealing material; the left casing (1) forms a closed cavity with the supporting cylinder (9) and the left cymbal-shaped diaphragm (201); the right casing (5) A closed cavity is formed with the supporting cylinder (9) and the right cymbal-shaped diaphragm (401); the left cymbal-shaped diaphragm (201), the right cymbal-shaped diaphragm (401), the supporting cylinder (9) and the sound-transmitting rubber sleeve (3) An oil cavity is formed, and the interior is filled with oil; there are holes on the upper and lower sides of the middle of the support cylinder (9), which are used to transmit the sound pressure in the water.

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