A fiber laser hydrophone optical path structure and signal demodulation method

Abstract

The invention discloses an optical fiber laser hydrophone optical path structure and a signal demodulation method. The structure comprises a pump laser, a wavelength division multiplexer, an optical fiber laser hydrophone, an isolator, a non-equilibrium Michelson interferometer, a photoelectric detector, an analog-to-digital converter and a digital modulation and demodulation module. The non-equilibrium Michelson interferometer performs carrier modulation on an optical signal carrying an external acoustic signal so as to obtain an interference optical signal carrying the external acoustic signal. The photoelectric detector converts the interference optical signal carrying the external acoustic signal into an analog electric signal carrying the external acoustic signal and transmits the analog electric signal to the analog-to-digital converter. The analog-to-digital converter converts the analog electric signal into a digital electric signal and inputs the digital electric signal to thedigital modulation and demodulation module to perform signal demodulation so as to obtain the corresponding information of the external acoustic signal. The manufacturing technology is enabled to besimple, the anti-noise capacity is high, the real-time performance is great and large-scale reuse of the optical fiber laser hydrophone is facilitated.

Description

technical field [0001] The invention relates to the field of optical fiber hydrophones, in particular to an optical path structure and a signal demodulation method of an optical fiber laser hydrophone. Background technique [0002] Fiber laser hydrophones not only have the advantages of grating sensor wavelength encoding, strong anti-interference ability, small probe size, and easy wavelength division multiplexing, but also have the advantages of extremely high sensitivity of phase interference sensors, so they have attracted close attention from scientists at home and abroad. In terms of military use, fiber optic laser hydrophones can become a new type of hydrophone for ship monitoring, etc.; after slight modification, fiber optic laser hydrophones can be used for civilian purposes, such as oil field exploration, ocean and river resource development and earthquakes Monitoring environmental noise assessment. The high responsivity of fiber laser hydrophones to environmental ...

AI Technical Summary

Problems solved by technology

Currently, the unbalanced Mach-Zehnder interferometer is commonly used to measure the wavelength change by interferometry, but this interferometer has certain limitations: the unbalanced Mach-Zehnder interferometer needs two The process design of the unbalanced Mach-Zehnder interferometer has brought challenges; the structure of the unbalanced Mach-Zehnder interferometer does not have a Faraday rotation mirror, which cannot effectively eliminate the polarization fading of the optical signal

These signal processing algorithms also have certain limitations: the consistency of the analog circuit form is poor, the anti-interference ability is poor, and the signal delay time is not easy to control; The base frequency signal is not easy to filter out by analog circuit, and will affect the final demodulation result; in the form of digital circuit DSP, DSP is limited by hardware structure conditions, serial operation, and real-time performance is poor, which is not conducive to large-scale fiber laser hydrophones reuse

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