Hydrophone detection device and method based on low bending loss chirped grating array

Abstract

The invention discloses an enhanced hydrophone detection device based on a low bending loss chirped grating array optical fiber, which includes an interference type distributed optical fiber grating acoustic sensor demodulator, a low bending loss chirped grating array optical fiber and a metal elastic circle The low bending loss chirped grating array fiber is prepared online based on the low loss bending insensitive single-mode fiber. The optical fiber between two adjacent chirped grating array fibers in the low bending loss chirped grating array fiber constitutes the grating detection area. The grating The measurement area includes an odd-numbered chirped grating measurement area and an even-numbered chirped grating measurement area, wherein the odd-numbered chirped grating measurement area is wound on the metal elastic cylinder, and the even-numbered grating measurement area is linearly arranged along the length direction of the metal elastic cylinder. The optical signal output end of the interferometric distributed fiber grating acoustic sensor demodulator is connected to one end of the low bending loss chirped grating array fiber, and the other end of the low bending loss chirped grating array fiber is knotted and suspended or connected to a fiber terminator.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a hydrophone detection device and method based on a low bending loss chirped grating array. Background technique [0002] 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 that uses sound waves propagating in the ocean as an information carrier to detect underwater targets and realize underwater navigation, measurement and communication. [0003] Piezoelectric hydrophones and interferometric fiber optic hydrophones are currently the most widely used underwater acoustic detection devices. Piezoelectric hydrophones were developed earlier, the technology is more mature, the structure and manufacturing process are simpler, and the consistency can be relatively well controlled during mass production. However, piezoelectric hydrophones have outstanding problems such as resistance to electrom...

AI Technical Summary

Problems solved by technology

However, the backward Rayleigh scattering used in this method has low coupling efficiency and weak reflectivity, resulting in low signal-to-noise ratio, low sensitivity, and poor response.

Moreover, this method is based on the optical fiber as the sensor, and its transmission and sensing are the same optical fiber, which will cause the transmission loss of the optical signal while increasing the sensitivity to the underwater acoustic signal detection, and further reduce the signal ratio, so it is difficult to detect the underwater acoustic wave. structurally sensitized

In summary, fiber optic distributed acoustic detection (DAS) technology is difficult to meet the requirements of high signal-to-noise ratio and high sensitivity in hydrophones (Reference: Dong Jie. Optical fiber distributed underwater acoustic measurement with spatial differential interference[J]. Optical Precision Engineering, 2017(9).)

[0008] It is difficult for the above methods to meet the requirements of distributed hydroacoustic detection with structurally sensitized, large-scale array, long detection distance, and fine linearity at the same time.

Images