光纤布拉格光栅地听器设计研究

Study on Fiber Bragg Grating-Based Geophone

近年来,对地声信号的探测技术在石油天然气勘探、地面和近海岸安全警界、海洋远距离目标探测和地下管道监测等领域得到飞速发展。为实现对低频地声信号的高品质探测,设计了一种双光栅对称推挽式结构的光纤布拉格光栅地听器,进行了结构理论、仿真分析、优化设计和三维结构扩展的研究。结果表明,该结构地听器具有较高的灵敏度,可达765.6pm/g;在1～120Hz之间,灵敏度动态响应特性良好;具有温度自补偿功能和较好的方向性;能够方便的扩展到三维结构;具有较好的对低频地声信号探测性能力。

In recent years, geophysical detecting technologies develop increasingly in fields, such as petroleum and natural gas exploration, safety alert of ground and coast, target detection in the ocean and underground pipeline monitoring. To realize high precision detection of low-frequency geophysical signals, a novel kind of geophone based on fiber Bragg gratting （FBG） with symmetrcal push-pull structure is designed. In-depth studies are made on structural theories, simulation analysis, optimization design and three-dimensional structure. Results show that the geophone has high sensitivity up to 765. 6 pm/g, and dynamic response character of 1 - 120 Hz is good. Furthermore, it has the function of temperature self-compensation, good direction characters, and can easy to realize three-dimensional structure. So the geophone has the ability of detecting low-frequency geophysical signals.