CN-224216163-U - Optical fiber hydrophone with double interferometers for push-pull and common mode noise differential suppression

CN224216163UCN 224216163 UCN224216163 UCN 224216163UCN-224216163-U

Abstract

The utility model is applicable to the technical field of optical fiber sensing, and relates to an optical fiber hydrophone with double interferometers for push-pull and common mode noise differential suppression, which comprises a first thin-wall cylinder, a second thin-wall cylinder, a first optical fiber interferometer and a second optical fiber interferometer; the first optical fiber interferometer comprises a first short arm sensing optical fiber, a first long arm sensing optical fiber, a first Faraday rotator and a second Faraday rotator, and the second optical fiber interferometer comprises a second short arm sensing optical fiber, a second long arm sensing optical fiber, a third Faraday rotator and a fourth Faraday rotator. The utility model adopts the double optical fiber interferometer to form a double push-pull structure, reduces temperature drift noise and optical scattering noise brought by the ultra-long sensing optical fiber, and inhibits common mode noise formed by light source vibration, transmission optical cable jitter and the like.

Inventors

JIANG PENG
LUO HONG
XU DONG
SHI TAO
WU JIE
DENG ZHIRU
GUO YUNDONG
LIU ZHONG

Assignees

长沙深之瞳信息科技有限公司

Dates

Publication Date: 20260508
Application Date: 20250616

Claims (10)

1. A dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone comprising: the optical fiber interferometer comprises a first thin-walled cylinder, a second thin-walled cylinder, a first optical fiber interferometer and a second optical fiber interferometer; the first thin-wall cylinder is embedded in the second thin-wall cylinder, an air cavity is formed by the first thin-wall cylinder and the second thin-wall cylinder, a first optical fiber winding area and a second optical fiber winding area are arranged on the first thin-wall cylinder, and a third optical fiber winding area and a fourth optical fiber winding area are arranged on the second thin-wall cylinder; The first optical fiber interferometer comprises a first short-arm sensing optical fiber, a first long-arm sensing optical fiber, a first Faraday rotator and a second Faraday rotator, the second optical fiber interferometer comprises a second short-arm sensing optical fiber, a second long-arm sensing optical fiber, a third Faraday rotator and a fourth Faraday rotator, the first short-arm sensing optical fiber is connected with the first Faraday rotator, the first long-arm sensing optical fiber is connected with the second Faraday rotator, the second short-arm sensing optical fiber is connected with the third Faraday rotator, the second long-arm sensing optical fiber is connected with the fourth Faraday rotator, the first short-arm sensing optical fiber and the second long-arm sensing optical fiber are wound on the first optical fiber winding area and the second optical fiber winding area in parallel, the first Faraday rotator and the fourth Faraday rotator are fixedly connected with the inner wall of the first thin-wall cylinder, and the first long-arm sensing optical fiber and the second short-arm sensing optical fiber are wound on the third optical fiber winding area and the fourth optical fiber winding area in parallel, and the first Faraday rotator is fixedly connected with the inner wall of the fourth optical fiber winding area.
2. The optical fiber hydrophone with double interferometer push-pull and common mode noise differential suppression according to claim 1, wherein a first support rib, a second support rib and a third support rib are further arranged on the first thin-walled cylinder, the first support rib and the third support rib are respectively arranged at two ends of the first thin-walled cylinder, and the second support rib is arranged at the middle position of the first thin-walled cylinder.
3. The optical fiber hydrophone with double interferometer push-pull and common mode noise differential suppression according to claim 2, wherein a fourth support rib, a fifth support rib and a sixth support rib are further arranged on the second thin-walled cylinder, the fourth support rib and the sixth support rib are respectively arranged at two ends of the second thin-walled cylinder, and the fifth support rib is arranged at the middle position of the second thin-walled cylinder.
4. A dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone as defined in claim 3 wherein the first, second and third support ribs have the same outer diameter and the same inner diameter as the second thin walled cylinder.
5. The optical fiber hydrophone with double interferometer push-pull and common mode noise differential suppression according to claim 4, wherein the second support rib, the third support rib, the fifth support rib and the sixth support rib are respectively provided with left and right spiral grooves with the same pitch and depth, and the left and right spiral grooves are used for crossing the support ribs and entering adjacent optical fiber winding areas when optical fibers are wound.
6. The dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone of claim 1, wherein the first fiber optic interferometer further comprises a first fiber optic coupler, the first short arm sensing fiber and the first long arm sensing fiber being connected to the first fiber optic coupler, respectively.
7. The dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone of claim 6, wherein the first fiber optic interferometer further comprises a first optical input pigtail and a first optical output pigtail, the first optical input pigtail and the first optical output pigtail being connected to the first fiber optic coupler, respectively.
8. The dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone of claim 1, wherein the second fiber optic interferometer further comprises a second fiber optic coupler, the second short arm sensing fiber and the second long arm sensing fiber being connected to the second fiber optic coupler, respectively.
9. The dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone of claim 8, wherein the second fiber optic interferometer further comprises a second optical input pigtail and a second optical output pigtail, the second optical input pigtail and the second optical output pigtail being connected to the second fiber optic coupler, respectively.
10. The dual interferometer push-pull and common mode noise differentially suppressed fiber optic hydrophone of claim 1, wherein the number of fiber optic winding layers is two.

Description

Optical fiber hydrophone with double interferometers for push-pull and common mode noise differential suppression Technical Field The utility model belongs to the technical field of optical fiber sensing, and particularly relates to an optical fiber hydrophone with double interferometers for push-pull and common mode noise differential suppression. Background The optical fiber hydrophone is an underwater acoustic sensor based on optical fiber and photoelectron technology, has the characteristics of electromagnetic interference resistance, small signal crosstalk, easiness in large-scale array formation and the like, is widely focused at home and abroad, and becomes an important novel technical approach of underwater target detection and underwater acoustic investigation equipment. The optical fiber hydrophone is divided into a wavelength type, an intensity type, an interference type and the like according to the detection principle, wherein the interference type optical fiber hydrophone has the characteristics of high sensitivity, easiness in forming an array, friendly process implementation and the like, and becomes a mainstream technical scheme in the industry. The traditional interference type optical fiber hydrophone is based on a single optical fiber interferometer structure, on the premise that the frame material and the structural parameters of the hydrophone are determined to ensure the hydrostatic pressure resistance, the sound pressure phase shift sensitivity is generally improved by prolonging the sensing optical fiber length of the optical fiber interferometer, however, when the sensing optical fiber length is increased to a certain extent, the increase of the temperature drift noise and the optical scattering noise of the optical fiber hydrophone is brought about by the increase of the optical fiber length, the background phase noise of the system is lifted, the equivalent noise pressure is increased, in addition, the vibration of a transmission optical cable and the low-frequency noise of a light source are difficult to eliminate in the optical fiber hydrophone of the single optical fiber interferometer structure, and although the self-adaptive elimination of the vibration of the transmission optical cable and the low-frequency noise of the system is carried out by adopting the sound pressure insensitive optical fiber hydrophone with the same parameters in the prior art, the sound pressure insensitive optical fiber hydrophone cannot realize the absolute same-point detection with the detection hydrophone, so that the inhibition capability is limited. The publication No. cn202020809189.X provides an interferometric fiber optic vector hydrophone with a reference interferometer, comprising a mass, an elastic tube, and a fiber optic interferometer, a housing for the mass, the elastic tube, and the fiber optic interferometer. The optical fiber hydrophone in the patent also adopts a single optical fiber interferometer structure, has poor inhibition effect and has the same defects as the prior art. Therefore, how to solve the problem that the shake of the ultra-long sensing optical fiber and the transmission optical cable and the low-frequency noise of the light source are difficult to inhibit in the sensitization design of the traditional optical fiber hydrophone is not enough. Disclosure of utility model Aiming at the defects of the prior art, the utility model aims to provide an optical fiber hydrophone with double interferometer push-pull and common mode noise differential suppression, so as to solve the problem that the ultra-long sensing optical fiber, the jitter of a transmission optical cable and the low-frequency noise of a light source are difficult to suppress in the sensitization design of the traditional optical fiber hydrophone. In order to solve the technical problems, the utility model adopts the following technical scheme: the utility model provides an optical fiber hydrophone with double interferometers for push-pull and common mode noise differential suppression, which comprises: The first thin-wall cylinder is embedded in the second thin-wall cylinder, an air cavity is formed between the first thin-wall cylinder and the second thin-wall cylinder, a first optical fiber winding area and a second optical fiber winding area are arranged on the first thin-wall cylinder, a third optical fiber winding area and a fourth optical fiber winding area are arranged on the second thin-wall cylinder, the first optical fiber interferometer comprises a first short-arm sensing optical fiber, a first long-arm sensing optical fiber, a first Faraday rotator and a second Faraday rotator, the second optical fiber interferometer comprises a second short-arm sensing optical fiber, a second long-arm sensing optical fiber, a third Faraday rotator and a fourth Faraday rotator, the first short-arm sensing optical fiber is connected with the second Faraday rotator, the second short-arm sensing optical fiber is co