Optical Heterodyne And Time Division Multiplexing Technology In Large-Scale Fiber Optic Hydrophone Array

Fiber-optic hydrophones are heading for the large-scale arrays. Time-Division-Multiplexing (TDM) is one of the most basic and effective schemes that large- scale array could adopt.Demodulation technique of the fiber optic hydrophone signal decides the configuration of light-pass and the multiplexing structure, as well as the dynamic range of the detection. The dissertation presents a new heterodyne demodulation method with optical heterodyne technique to obtain the reference signal. Arithmetic is designed and realized in digital technique to demodulate the phase information of the heterodyne signal. Simulation is done using the demodulation method and the results are analyzed. A TDM fiber-optic hydrophone array system based on the heterodyne demodulation is developed. The experiments are carried out using one of the element signals. Simulating acoustic signal of different frequency and different amplitude are used in the experiment. The experiment results show that the signal between 1kHz and 50kHz could be demodulated using the system we have constructed. Amplitude of the demodulation signal changes linearly with that of the simulated acoustic signal's amplitude. The results prove that the system could answer require of high frequency and amplitude range detection in the submarine. This will promote the development of the large-scale fiber-optic hydrophone array.