基于长周期光纤光栅的新型地震检波器

Novel geophone based on long period fiber grating

基于长周期光纤光栅能透射特定波长的性质,以及其无后向反射的优点,提出一种新型的长周期光纤光栅地震检波器系统。以长周期光纤光栅相位匹配条件为基础,逐步推导出长周期光纤光栅地震检波器的灵敏度公式。建立长周期光纤光栅地震检波器的力学模型,并推导出检波器系统的传递函数。通过实例仿真得到该长周期光纤光栅地震检波系统的幅频特性图,从而证明了长周期光纤光栅用于地震检波器的可行性。通过调整光纤长度、质量块质量、阻尼系数等参数而得到适合的频率特性和灵敏度,为将来提高该系统的性能指明了研究方向。

A new type of geophone is presented, based on the narrow band transmission and free of back reflection features of long period fiber grating. The acceleration sensitivity of the resonance wavelength of the long period fiber grating geophone system was deduced and analyzed with the phase matching of long period fiber grating as preconditions. The mechanic model of the long period fiber grating geophone was established and the transfer function of the geophone was deduced. Through simulating a simple example, the amplitude-frequency characteristics of the long period fiber grating geophone was obtained, and its feasibility was proved. The parameters such as length of the optical fiber, the mass of the mass block and the damping factor were improved to achieve proper frequency feature and sensitivity.