摘要
地表运动的旋转量观测在地震学、地球物理学及工程勘察等研究中具有重要意义,基于Sagnac效应的光纤陀螺由于其全固态、高灵敏度和宽频响特性等优势,受到旋转地震仪研究和开发的广泛关注.为了提高光纤旋转地震仪的灵敏度一般采用长光纤环,然而随着光纤长度的增加,光纤环内的热相位噪声、光源的相对强度噪声等限制了其灵敏度性能提高.本文针对影响光纤旋转地震仪灵敏度的噪声展开了深入分析,利用保偏光纤的快慢轴提出了双偏振工作方案,对其光学结构和解调算法进行了理论分析,结果表明该方案可有效抑制热相位噪声与光源相对强度噪声.在此基础上,研制了三分量双偏振光纤旋转地震仪DP-Rot3C,并对其进行了静态测试和动态测试.结果显示,该仪器的灵敏度达到了20 nrad·s^(-1)·√Hz^(-1),与法国Bluseis-3A相当,且在0.01~125 Hz频率范围内响应平坦,在-300~+300°/s的量程范围内非线性度小于6 ppm(1 ppm=0.0001%),具有高精度、宽频带、大量程、高线性度的特性.DP-Rot3C还运用于人工主动源观测、高铁地震观测、天然地震观测等领域,为工程勘探、地震研究等应用提供了高精度观测地表运动旋转量的工具.
The observation of the rotation of surface motion is of great significance in seismology,geophysics,engineering exploration,and other research fields.Interferometer fiber optic gyroscopes based on the Sagnac effect have attracted extensive attention in the research and development of rotational seismometers due to their advantages of all-solid-state,highly sensitivity and wide frequency response.To enhance the sensitivity of fiber optic rotational seismometers,long fiber loops are commonly employed.However,increasing the length of the optical fiber leads to thermal phase noise and relative intensity noise from the light source within the optical fiber loop,limiting their sensitivity performance.This paper conducts an in-depth analysis on the noises that degrade the sensitivity of fiber optic rotational seismometer.A dual-polarization configuration is proposed using the slow and fast axes of polarization-maintaining fibers,and its optical configuration as well as demodulation algorithm are theoretically analyzed.The results show that the dual-polarization configuration can effectively suppress thermal phase noise and relative intensity noise.On this basis,a three-component dual-polarization fiber optic rotational seismometer DP-Rot3C is developed,and the static and dynamic tests are conducted.The results show that the sensitivity of the seismometer reaches 20 nrad·s^(-1)·√Hz^(-1),comparable to the French Bluseis-3A.It exhibits a flat response across a frequency range of 0.01~125 Hz and possesses a nonlinearity of less than 6ppm(1 ppm=0.0001%)over a dynamic range of-300 to+300°/s.These results demonstrate that DP-Rot3C has high precision,wide frequency band,large dynamic range and high linearity.DP-Rot3C has been applied in multiple practical scenarios,including artificial active source observation,high-speed-railway seismology observation,natural earthquake observation,and other fields.The above experiments indicate that DP-Rot3C provides a high-precision tool for observing the rotation motion for engineering exploration,seismological research,and other applications.
作者
朱兰鑫
陈彦钧
王文伯
曹瑜珈
黄慧敏
张丁凡
李正斌
ZHU LanXin;CHEN YanJun;WANG WenBo;CAO YuJia;HUANG HuiMin;ZHANG DingFan;LI ZhengBin(State Key Laboratory of Regional Optical Fiber Communication Network and New Optical Communication System,School of Electronics,Peking University,Beijing 100871,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Hangzhou Youfu Technology Co.,Ltd.,Hangzhou 311215,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第12期4594-4610,共17页
Chinese Journal of Geophysics
基金
国家自然科学基金(U1939207)
国家重点研发计划(2019YFC1509501)资助。
关键词
光纤旋转地震仪
双偏振结构
旋转地震学
相对强度噪声
热相位噪声
Fiber optic rotational seismometer
Dual-polarization configuration
Rotational seismology
Relative intensity noise
Thermal phase noise
作者简介
第一作者:朱兰鑫,男,主要从事高精度光纤旋转地震仪研究.E-mail:zhulanxin2020@stu.pku.edu.cn;通讯作者:陈彦钧,男,1997年生,2024年于北京大学获博士学位,现为中南大学特聘副教授,主要从事地球物理光纤传感器及其信号处理研究.E-mail:chenyanjun@csu.edu.cn。
