High-stability signal demodulation method for interferometric fiber optic hydrophone

Abstract

The invention discloses a high-stability signal demodulation method for an interferometric fiber optic hydrophone, which comprises the steps that S100, a laser applies sinusoidal frequency modulationand inputs the output light wave into a non-equilibrium interferometric fiber optic hydrophone, the fiber optic hydrophone applies a large-amplitude test acoustic signal, the fiber optic hydrophone inputs the output test interferometric signal into a signal demodulation system and processes the test interferometric signal to obtain demodulation system parameter estimated values; and S200, the fiber optic hydrophone is placed in the measurement environment to measure the tested acoustic signal, and the fiber optic hydrophone outputs an actual interferometric signal into the signal demodulationsystem, processes the actual interferometric signal and then obtain the tested acoustic signal after being corrected by the demodulation system parameter estimated values. The method disclosed by theinvention realizes high-stability signal detection of the interferometric fiber optic hydrophone.

Description

technical field [0001] The invention relates to the technical field of signal demodulation of optical fiber hydrophones, in particular to an interference type optical fiber hydrophone signal demodulation method. Background technique [0002] Optical fiber hydrophone is a new type of underwater acoustic sensor, which has the characteristics of high sensitivity, smart structure, and easy reuse to form a large-scale array. It has important applications in underwater target detection, seismic wave detection and other fields. Among various types of fiber optic hydrophones, the interferometric fiber optic sensor is based on the fiber optic interferometer structure. Through high-sensitivity coherent detection technology, the measured signal is loaded in the output signal of the sensor in the form of phase, which has high sensitivity and low noise. Many excellent characteristics. However, due to the random phase fading phenomenon of the interferometric fiber optic hydrophone, signa...

AI Technical Summary

Problems solved by technology

For example, in the application of vector optical fiber hydrophone, the estimation of the target azimuth can be realized by comparing the signal amplitude of the orthogonal hydrophone channel, and the instability of the demodulated signal will directly lead to the estimation error of the target azimuth; In the application of the earphone array, the signal instability will affect the amplitude consistency between the multi-channel fiber optic hydrophone elements, which will directly lead to the decrease of the array gain level and seriously affect the performance of the array application.

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