Acoustic sensing demodulation system and method based on lithium niobate electro-optic modulation and polarization interference

Abstract

The application discloses a kind of acoustic sensing demodulation system and method based on lithium niobate electro-optic modulation and polarization interference, the light emitted by low coherence light source (1) enters fiber optic circulator (2) into fiber optic Fabry-Perot sensor (3), and the interference light beam returned after dynamic signal modulation is introduced into fiber optic beam splitter (4), and is divided into two-path low coherence demodulation processing and another path self-compensation processing;All paths are accessed collimating mirror to collimate light beam, form three path space beams, obtain two low coherence interference signals and one real-time compensation interference signal;Photoelectric detector collects analog signal, and converts into digital signal;Data processing is carried out to digital signal, completes the normalization of interference signal and the compensation processing of normalization result, and the signal after compensation processing is demodulated, and the phase information of cavity length change is obtained.The application realizes high-stability fiber optic Fabry-Perot F-P dynamic phase demodulation.

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