【作者】 吴波；

【导师】 陈才和；

【作者基本信息】 天津大学 ， 物理电子学， 2005， 博士

【摘要】 能源安全是国民经济和社会发展乃至国家安全的前提,石油供应安全是国家能源安全问题中最为迫切的问题。为缓解我国油气供不应求的现状,寻找油气勘探战略接替区已经成为当务之急。鉴于容易找到的资源已经被发现和开采,亟待于提高勘探技术。地震检波器作为执行地震勘探的第一道工序的仪器,其性能的好坏,直接影响到地震数据采集的质量。本研究为国家自然科学基金资助项目“光电集成加速度地震检波技术理论与实验研究”(No.40274047)的主课题。该研究首次提出一种新型的微光机械加速度地震检波器,该器件集光波导传感技术与硅微机械技术于一体,具有高灵敏度、宽频带、高精度、体积小、集成度髙等优良特性,适合在高温高寒等恶劣环境下稳定工作,而且有望解决传统光纤传感器向微型化和批量生产时遇到的装配困难及长期稳定性问题。本论文主要完成以下研究工作: 1.系统研究了各种光波调制传感器,重点研究了光相位调制传感器。详细研究了相位调制型波导传感器的传感机理,分析了应力应变效应和温度应变效应引起的相位变化机理。从晶体光学出发,详细推导了光弹效应引起的相位变化,给出了相位变化公式。最后探讨了光相位解调方法。2.详细分析了硅微光机械加速度地震检波器的静态工作特性和动态工作特性,给出了其核心-简谐振子系统的优化结构设计。从悬臂梁的小应变理论和弯曲应力理论出发,并应用广义虎克定律对“十字梁-质量块”简谐系统的梁形变和应力应变进行了详细的分析推导,讨论分析了相位灵敏度。建立了该加速度地震检波数学模型,对其幅频特性和相频特性,以及阻尼对系统特性的影响进行了分析讨论。通过综合考虑,得到优化结构参数。用有限元软件ANSYS对系统进行了建模仿真。分析讨论了该加速度地震检波器的量程和横向灵敏度。最后对所应用的小挠度理论的使用范围进行了讨论。3.对硅基微光机械加速度地震检波器的Mach-Zehnder光波导干涉仪系统进行了系统研究和优化设计。从导波的射线理论出发,导出了波导单模条件,运用有效折射率法完成了单模波导的优化设计。对Y分支波导的工作原理和损耗特性进行了深入地分析研究,完成了分支波导优化设计。为了实现大角度光路转向,采用波导转向镜结构,完成了优化设计。对光束传播法进行了深入研究,并对Y分支波导进行模拟仿真和分析研究。分析讨论了金属包覆/介质缓冲层的偏振器,给出了TE0、TM0模吸收损耗系数和缓冲层厚度的关系图,实现了TE模偏振器的优更多还原

【Abstract】 Energy is the basis of the safety of national economy and even of the country itself. The safety of petroleum supplies is important in the safety of national energy. To solve our country energy crisis, it is urgent to prospect new oil fields or other energy. As the easily discoverable energy has been exploited, the prospecting will become more and more difficult, and we need to improve the prospecting technology urgently. Seismic geophone, which work first in the seismic prospecting, decide the quality of the collected seismic data. 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” , supported by National Natural Science Foundation of China. A novel MOEMS acceleration seismic geophone has been developed. Combining MEMS technology with Integrated optical technology, it is of the advantages such as potential high sensitivity, wide bandwidth, high degree of accuracy and environmental ruggedness, and suitable for mass production. It is also possible to overcome optical alignment ,long-term stable and handing of fiber in package process when optical fiber sensor is minimized and go into mass production. The research work of the dissertation mainly includes four aspects as follows: 1. Kinds of optical modulation sensors, especially lightwave phase modulation sensors are studied. Sensor principle of waveguide sensor based on light phase modulation is researched. The phase change, generated by stress-strain effect and temperature-strain effect, is analyzed. Starting with the crystal optics theory, the phase change, generated by photoelastic effect, is derived. The methods for lightwave phase demodulation are discussed. 2. Analysis of the static and dynamic behavior of Si-based MOEMS acceleration seismic geophone are given and the optimization structure design of the harmonic oscillator is obtained. Starting with small-deflection theory and bending stress theory of beam, the beams’ length change of the harmonic oscillator is derived, and beams’ stress-strain is also obtained using general Hooke’s law. And the phase sensitivity is discussed. The mathematical model of the MOEMS acceleration seismic geophone is established, and amplitude, phase frequency response characteristics and damping effect are studied. On the basis of above analysis, optimization structure design of the harmonic oscillator is obtained. The simulation of behavior of sensor is performed by the FEM software ANSYS. Measuring range and cross-axis sensitivity are discussed. The work condition of the small-deflection theory is verified. 3. Mach-Zehnder waveguide interferometer of Si-based MOEMS acceleration seismic geophone is researched and its optimization structure design is accomplished. Starting with waveguide ray theory, the condition for single-mode waveguide is derived, and design of single-mode strip waveguide is accomplished with effective index method. The working principle and loss characteristics of Y-branching waveguide are studied, and waveguide turning mirror with a 90°directional change is employed and designed. The Helmholtz equation, the intrinsic equation of waveguide, is derived. BPM (beam propagation method), one of its’ numerical solution, is studied and employed to simulate the lightwave propagation in Y-branching waveguide. The polarizer , which adapts structure of metal cladding/dielectric buffer layer, is studied, and TE mode polarizer is designed. 4.Lots of theoretical and experimental research on process craft of waveguide interferometer and harmonic oscillator have been done. A feasible process flow is made and valuable technological parameter are obtained. And Mach-Zehnder waveguide interference chip is fabricated successfully and the optical measurement is executed. A harmonic oscillator is also processed.更多还原