【作者】 唐东林；

【导师】 陈才和；

【作者基本信息】 天津大学 ， 物理电子学， 2006， 博士

【摘要】 为提高石油天然气产量,石油地震勘探正朝着多波多分量的三维精细地震勘探发展,以寻找储藏在浅层、薄层的油气。因此,检波器作为地震勘探中地震反射波信号的拾取单元,必须满足三分量地震勘探对其频带、分量间串扰、灵敏度、野外施工适应性等各项性能的要求。本课题首次提出基于光弹效应的三分量混合集成加速度地震检波器,很好地结合了光波导技术和三分量地震加速度检波技术,与其他三分量检波器相比有频带更宽、分量间串扰低、灵敏度高的优点。同时由于光波导集成器件本身的特点,所研制的三分量加速度检波器体积小、适合在强电磁场和高温高寒等恶劣环境下稳定工作。论文的主要研究工作如下:1、首先建立三分量光弹波导混合集成加速度地震检波器动力学模型、微分运动方程,系统分析并计算加速度检波器的幅频特性、相频特性、阶跃响应以及其静态特性,为加速度检波器结构设计奠定振动力学理论基础。2、首次从单向力作用下晶体光弹效应出发,详细推导出在空间加速度作用下,LiNbO3晶体的三维光弹效应,采用坐标变换法推导出:通过LiNbO3晶体的光相位变化与三分量加速度变化的对应关系,为加速度检波器结构设计奠定光学理论基础。3、基于LiNbO3晶体的光弹效应,详细分析计算三分量光弹波导加速度检波器的极间耦合影响,结合对三分量检波器的振动力学和光学理论分析,最终确定分量间串扰值为零的加速度检波器结构设计。4、对三分量光弹波导混合集成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,根据波导单模条件,结合有效折射率法完成了单模波导的优化设计。结合有效折射率法,二维空间有限差分光传播法和透明边界条件,对S形反正弦波导构成的双Y分支波导光路传输进行深入分析研究,对波导传输损耗进行了计算分析,在此基础上设计的双马赫-曾德干涉仪具有良好的分光比和低损耗的优点。5、对波导干涉仪的制作工艺进行了详尽的理论和实验研究。通过大量的实验制定出了切实可行的工艺流程,获得了有参考价值的工艺参数。成功研制分支波导结构复杂、波导间隔小的干涉芯片并完成通光实验。更多还原

【Abstract】 In order to improve the oil and gas reserves, people used 3-D seismic exploration to find the oil and gas storage in the shallow and thin layers. The multicomponent seismic exploration requires 3-component seismic signals, which are measured by 3-component geophone in an earthquake. 3-component geophone can measure back and forth horizontal motions in two directions. It is a important thing for 3-D seismic exploration to choose a 3-component geophone with suitable parameters, including nature frequency; cross-axis sensitivity; on-axis sensitivity and applicability for field exploration.In this dissertation, the three-component hybrid-integrated optical acceleration seismic geophone based on photoelastic waveguide is introduced for the first time, which contains the photoelastic waveguide technology and 3-component seismic signal detection technology. Compared with other 3-component geophones, this acceleration geophone has broad-band frequency; low cross-axis sensitivity; high on-axis sensitivity. 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 we model the three-component hybrid-integrated optical acceleration seismic geophone by the system consisting of masses; spring and dampers. The differential equation of motion for the system is found. The static characteristic and dynamic characteristic of 3-component hybrid-integrated optical acceleration seismic geophone (such as: frequency response; phase response; step response etc.) are studied, which are bases of the vibration theory for design the three-component hybrid-integrated optical acceleration seismic geophone2 based on the one-dimensional photoelasitcity when one-dimensional stress is applied on LiNbO3 crystal, we derive the 3-dimensional photoelasitcity when 3-dimensional stress is applied on LiNbO3 crystal. Applying the method of coordinate transform, we obtain the relationship between phase change of light and 3- component acceleration applied on LiNbO3 crystal. The relation is the theory base for designing the three-component hybrid-integrated optical acceleration seismic geophone.3 After obtaining the 3-dimensional photoelasitcity of LiNbO3 crystal, we analyse the level of sensitivity to off-axis accelerations which is a very important parameter for3-axis accelerometer. Combining with the mechanical libration theory and photoelasitcity theory, we design the 3-component hybrid-integrated optical acceleration seismic geophone which cross-sensitivity is 0.4 The Mach-Zehnder waveguide interferometer of the three-component hybrid-integrated optical acceleration seismic geophone is researched detailedly. The optimization structure design of the accelerometer is accomplished. Based on the waveguide ray theory, the condition for single-mode waveguide is derived, and design of single-mode strip waveguide is accomplished with effective index method. Combining with the effective index method, FD-BPM and TBC method, the Y-branching waveguide composed of reflected S-bend is researched. The lightwave propagation in Y-branching waveguide is studied and the FD-BPM method employed to simulate. The Mach-Zehnder waveguide interferometer we designed has good splitting ratio and low-loss.5 In order to make a good Mach-Zehnder waveguide interferometer, Lots of theoretical and experimental researches on process craft of waveguide interferometer have been done. A feasible process flow is made and valuable technological parameters are obtained. The Mach-Zehnder waveguide interferometer is fabricated successfully and the optical measurement is executed.更多还原