基于线性扫频的分布式光纤微震信号调制方法  

Distributed Optical Fiber Micro-Seismic Signal Modulation System Based on Linear Frequency Modulation

作　　者：崔少杰 康杰虎 吴斌[1] Cui Shaojie;Kang Jiehu;Wu Bin(State Key Laboratory of Precision Measuring Technology and Instruments,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学精密测试技术及仪器国家重点实验室,天津300072

出　　处：《激光与光电子学进展》2023年第23期116-122,共7页Laser & Optoelectronics Progress

基　　金：四川省科技支撑计划(2021YFSY0024)。

摘　　要：在页岩气的开采过程中,需要对压裂作业中产生的微震波进行检测。在传统的基于后向瑞利散射的分布式光纤传感技术的基础上,提出了一种应用于微震波检测的线性扫频脉冲调制方法。将调制系统中的矩形脉冲改为线性扫频脉冲,通过压缩脉冲匹配滤波的方式实现长距离、高空间分辨率传感。经过仿真与实验验证,选用线宽约为10 kHz的窄线宽激光器为光源,经电光调制与声光调制,可实现扫频范围为5.6~5.8 GHz、扫频时间为2μs、传感距离为10 km的线性扫频信号调制,接收到的后向瑞利散射信号强度范围为−60~−50 dBm。Based on the traditional distributed optical fiber sensing technology that uses back Rayleigh scattering,a linear sweep pulse modulation method for micro-seismic detection is proposed.The rectangular pulse in the modulation system is first transformed into a linear sweep pulse,and long-distance and high-spatial-resolution sensing is realized by compressing the pulse and matching filtering.Through simulation and experimental verifications,a narrow line-width laser with a line width of approximately 10 kHz is selected as the light source.Electro-optical and acousto-optical modulations determine the frequency scanning range and time as 5.6‒5.8 GHz and 2μs,respectively.Linear sweep signal modulation obtains a sensing distance of 10 km,and the intensity range of the received back Rayleigh scattering signal is−60~−50 dBm.

关 键 词：分布式声波传感 线性扫频 微震信号调制 微震检测技术 

分 类 号：TP202[自动化与计算机技术—检测技术与自动化装置]