基于3×3相位解调的光纤地震检波器研究

Research on the Fiber Geophone with 3×3 Phase Demodulation

针对基于3×3相位解调的光纤地震检波器展开研究。利用基于最小二乘法的椭圆拟合法和微分交叉相乘算法,实现基于3×3相位解调的光纤地震检波器的两路输出信号的归一化,减小光纤3×3耦合器的非对称性和激光器的功率波动对光纤地震检波器的影响,解调出光纤地震检波器的相位,实现振动信号的准确还原。实验采用对比法测试了基于3×3相位解调的光纤地震检波器的性能,其灵敏度为320 rad/g@100 Hz,在5~400 Hz频率范围内的波动约为0.7 dB。该研究能够很好地应用于石油、天然气等地质勘探、地震监测以及周界安防等领域。

In this paper,the fiber geophone with 3×3 phase demodulation is researched.By using ellipse fitting method based on least squares and differential-cross-multiplication algorithm,the two output signals of fiber geophone with 3×3 phase demodulation are normalized,reducing the influence of the asymmetry of the optical fiber 3×3 coupler and the power fluctuation of laser,and the phase of fiber geophone can be demodulated,restoring the vibration signal accurately.In the experiment,by using the comparison method,the performance of the fiber geophone with 3×3 phase demodulation is tested.The sensitivity of 320 rad/g in the 100 Hz can be achieved,and the fluctuation in the frequency range of 5~400 Hz is about 0.7 dB.The research can be well applied to the fields of geological exploration,seismic monitoring,perimeter security and so on.