Enhanced hydrophone detection device and method based on low-bending-loss chirped grating array optical fiber

Abstract

The invention discloses an enhanced hydrophone detection device based on a low-bending-loss chirped grating array optical fiber. The device comprises an interference type distributed fiber bragg grating acoustic sensing demodulator, a low-bending-loss chirped grating array optical fiber and a metal elastic cylinder. The low-bending-loss chirped grating array optical fiber is prepared on line basedon a low-bending-loss insensitive single-mode optical fiber. Optical fibers between every two adjacent chirped gratings in the low-bending-loss chirped grating array optical fiber form grating measuring areas. The grating measuring areas comprise the odd chirped grating measuring areas and the even chirped grating measuring areas. The odd chirped grating measuring areas are wound on the metal elastic cylinder, and the even chirped grating measuring areas are linearly distributed in the length direction of the metal elastic cylinder. The optical signal output end of the interference type distributed fiber bragg grating acoustic sensing demodulator is connected with one end of the low-bending-loss chirped grating array optical fiber, and the other end of the low-bending-loss chirped gratingarray optical fiber is knotted and suspended or connected with the optical fiber terminator.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to an enhanced hydrophone detection device and method based on low bending loss chirped grating array optical fiber. 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 ...

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.

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