All-optical hydrophone that is not sensitive to temperature or static pressure

A hydrophone and temperature change technology, which is applied in the direction of instruments, scientific instruments, seismic signal receivers, etc., can solve the problem that the axial deformation is not enough to obtain the sensitivity of the hydrophone

Active Publication Date: 2014-01-01
THALES SA
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  • Abstract
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AI Technical Summary

Problems solved by technology

[0012] However, there is DSP (density spectral power) about the intrinsic noise of the laser which limits the noise of the demodulation system ( to the order of 1 kHz), the axial deformation caused by the sound pressure applied directly to the outer surface of the laser cavity is insufficient to obtain a hydrophone sensitivity compatible with levels less than sea state noise 0

Method used

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  • All-optical hydrophone that is not sensitive to temperature or static pressure
  • All-optical hydrophone that is not sensitive to temperature or static pressure
  • All-optical hydrophone that is not sensitive to temperature or static pressure

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Embodiment Construction

[0052] The following description presents the characteristics of the optical hydrophone according to the invention by means of a preferred embodiment, which is used here as an exemplary embodiment and does not limit the scope or breadth of the invention. pass Figure 1 to Figure 6 In particular, the structure of this particular embodiment is illustrated, along with an explanation of the principles of its operation.

[0053] The hydrophone according to the invention comprises a protective mechanical structure defining a cavity 11 inside which a Bragg grating fiber optic element 12 is placed. In addition to the shielding function, this cavity also has the function of amplifying, in a known manner, the axial deformations exerted on the fiber optic element 12 by the dynamic pressure exerted by the external medium.

[0054] In a known manner, the fiber optic element 12 constituting the Bragg-grating fiber single-frequency laser cavity (which forms the sensitive part of the hydroph...

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Abstract

The invention consists of: an optical hydrophone; and a fiber-optic element which forms a laser cavity and is housed inside a mechanical structure comprising an open rigid cylindrical body that defines a cavity containing a fluid, in which cavity the fiber-optic element is housed, said rigid body being sealed at the ends thereof by means of two stoppers that keep the fiber-optic element permanently under tension in a longitudinal rectilinear position inside the cavity. The stoppers are configured such as to: deform when the external pressure varies, thereby varying the length of the fiber-optic element; and deform when the temperature varies, thereby varying the length of the fiber-optic element and compensating for the variation experienced by the element as a result of the temperature variation. The mechanical structure also includes one or more openings that allow the static pressures to be balanced.

Description

technical field [0001] The present invention relates to the general field of underwater acoustic transducers or hydrophones. In particular, the invention relates to optical hydrophones based on fiber lasers. Background technique [0002] With regard to the production of underwater acoustic transducers, the use of optical fibers is a known solution that exhibits recognized advantages, including above all the small size of the hydrophones produced with such technology, and the ability to produce The possibility of an ensemble of hydrophones by multiplexing on the same optical fiber the pressure change information detected by the individual hydrophones making up the ensemble of hydrophones, wherein each Hydrophones are associated with a given wavelength. [0003] However, in order to obtain a sensitivity sufficient to be able to detect very low levels of acoustic signals (usually levels below sea state noise 0 on the knudsen scale), it is known that the passage pressure The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01H9/00G01V1/18
CPCG01H9/004G01V1/188
Inventor M·杜瓦西F-X·洛奈R·拉尔达G·鲁
Owner THALES SA
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