Theoretical And Experimental Research On The Photo-electronic Integrated Acceleration Seismic Geophone

With the development of modern industry, the demands for oil energy are expanding increase. Because the easily discoverable oil energy has been exploited, the prospecting becomes more and more difficult, and it is urgent for us to improve the prospecting technology. To survey the geologic structure under ground or explore the energy, people use the method of seismic prospecting. Seismic geophone, which works first in the seismic prospecting, decides the quality of the exploration system.The research work of the dissertation is the main research item of the project"The theoretical and experimental research on photo-electronic integrated acceleration seismic geophone technology"(NO.40274047), supported by National Natural Science Foundation of China. The photo-electronic integrated acceleration seismic geophone, which is a novel MOEMS (Micro-Optic-Electro-Mechanical- System) acceleration seismic geophone, is of the advantages such as potential high sensitivity, wide bandwidth, high degree of accuracy and environmental ruggedness, and suitable for mass production. The research work of the dissertation mainly includes four aspects as follows:1. The principle of the photo-electronic integrated acceleration seismic geophone is researched. Lots of theoretical researches and process craft researches of harmonic oscillator and waveguide interferometer have been done. A feasible process flow is made and valuable technological parameter is obtained.2. The principle of acousto-optic waveguide phase modulation is studied. Starting with the theory of elastic wave, the motivation and the transmission of the SAW (Surface Acoustic Wave) is researched and the principle of IDT (Interdigital Transducers) is discussed. The optimization structure design of ZnO thin film and IDT are obtained and lots of the experimental craft of them have been done.3. Because the fabrication technology of the acousto-optic waveguide phase modulator is complex, and it is very difficult and expensive to monolithic integrated with M-Z interferometer and harmonic oscillator, the laser diode modulation is proposed. The principles of the laser diode modulation with a feedback control system and the signal processing method are analyzed. The realization scheme of signal processing of the geophone using FPGA (Field Programmable Gate Array) is proposed, which can improve the stability, flexibility and anti-interference of the circuit. The LPF (Low-Pass Filter) modular in the signal processing of the geophoneis issued. The DA (Distributed arithmetic) has many merits such as compact, engaging little resource, high working frequency. The simulation of the processing is performed, and this work establishes the groundwork for the further digitalization of the geophone.4. On the basis of the theory analyze and craft experiments, the system prototype has been fabricated and tested. The experimental result shows that the there are good linearity and high output in seismic prospecting domain and performance indexes reach the demands.