Noise Analysis and Optical Design of an Optical Fiber Seismometer with a Super-Long Refraction Arm
Noise Analysis and Optical Design of an Optical Fiber Seismometer with a Super-Long Refraction Arm
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超长折射臂光纤地震仪的噪声分析与光学设计
DOI：
10.1166/sl.2012.2456
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发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
Peng
中科院分区：
文献类型：
--
作者：
Wu, B.;Yang, J.;Yuan, Y. G.;You, J. G.;Peng
本文提出了一种基于超长臂光纤干涉仪的光纤地震仪，用于探测地震波。该干涉仪由一根缠绕在两个测量点之间的传感光纤和一根与振动完全隔离的参考光纤组成。无需惯性摆，直接检测固定在岩石上的两个测点之间的应变和振动即可获得地震信号。由于传感光纤的多层缠绕，使得传感器的应变和振动被放大。研究了光纤地震仪的光学结构和参数设计，分析了热噪声、瑞利噪声和弹丸噪声对地震仪的影响，优化了灵敏度和分辨率。实验结果表明，干涉臂长度为1000 m的地震仪的测量分辨率高于100 pm/Hz1/2。
In this paper, we proposed an fiber seismometer based on a fiber-optic interferometer with a superlong arm to detect seismic waves. The interferometer was composed of a sensing fiber which was wrapped between two measurement points, and a reference fiber which was completely isolated from the vibration. The seismic signal could be obtained by directly detecting the strain and vibration between two measurement points fixed on rocks without an inertial pendulum. The strain and vibration were amplified due to the multi-layer wrapped sensing fiber. We studied the optical structure and parameter design of the fiber seismometer, analyzed the effect of thermal noise, Rayleigh noise and shot noise, and optimized the sensitivity and resolution. The experimental results indicated that the measurement resolution of the seismometer with the interference arm length of 1000 m was higher than 100 pm/Hz1/2.