Fiber optic hydrophone remote transmission array system based on compensation interference as well as method

Abstract

The invention discloses a fiber optic hydrophone remote transmission array system based on compensation interference as well as a method. The system comprises a signal emission unit used for inputtinga pulse signal, a compensation interference unit which has unbalance arm difference and is used for converting the pulse signal into a pulse signal pair with delay and outputting the pulse signal pair with delay, an optical annular unit used for transmitting the pulse signal pair, a time division multiplexing array unit which is provided with a time division multiplexing array and used for splitting and delaying the pulse signal pair, merging all the delayed signals after a sensing signal is acquired and transmitting a time division multiplexing interference pulse signal provided with the sensing signal to a second port of the optical annular unit from an input output port and a signal receiving unit used for resolving the time division multiplexing interference pulse signal to obtain thesensing signal. The system disclosed by the invention can greatly enhance comprehensive performance of a large-scale fiber optic hydrophone remote transmission array, so that the large-scale fiber optic hydrophone remote transmission array can meet application requirements of related fields such as fiber optic hydrophone sealfloor shore-based fixed arrays.

Description

technical field [0001] The invention relates to the technical field of optical fiber hydrophones, in particular to an optical fiber hydrophone remote transmission array system and method based on compensation interference. Background technique [0002] Optical fiber hydrophone is a fiber optic sensor based on optical fiber and photoelectric technology, which uses sound waves to detect, locate and identify underwater acoustic targets. Optical fiber hydrophones have the advantages of small size and light weight, and can easily form various underwater optical fiber sensing networks, providing an ideal technical approach for solving problems related to marine development strategies such as underwater acoustic detection and oil exploration. Typical applications of fiber optic hydrophones include submarine shore-based fixed arrays, towed arrays, and snorkeling buoys. Among them, shore-based arrays have the advantages of stable formation, long-term continuous duty, and low self-noi...

AI Technical Summary

Problems solved by technology

[0004] (2) In terms of long-distance transmission technology of fiber optic hydrophones, with the increase of the transmission distance of analog optical signals, it is also accompanied by coherent Rayleigh scattering noise (Rayleigh), stimulated Brillouin scattering (stimulated Brillouin scattering, SBS), four The intensification of linear and nonlinear noises such as Four-Wave Mixing (FWM) will affect the weak acoustic signal detection ability of fiber optic hydrophones

[0008] 1. In the equi-arm compensation interference structure using heterodyne demodulation, the round-trip length of the array delay fiber is equal to the arm difference of the horse-increasing compensation interferometer, that is, the interference delay after compensation Δτ=0, resulting in Δf 2 ×Δτ≡0, unable to satisfy the phase modulation scheme Δf 2 ×Δτ=k (k is a positive integer) requirements

Therefore, the suppression of SBS noise in remote transmission can only be achieved by controlling the optical power injected into the remote fiber below the SBS threshold.

Compared with the phase modulation stimulated Brillouin scattering

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