摘要
相位敏感光时域反射系统以其分布式光纤传感技术的优势在分布式水听、压裂微地震检测、自然灾害预警等低频监测领域具有极高的应用前景。文中对系统中脉冲斩波信号与频率调制信号时钟不同源的问题予以验证,并对其产生的影响进行理论分析;设计双路同步时钟源驱动产生脉冲斩波信号和频率调制信号,降低每个脉冲重复周期中频率调制信号的随机低频相位噪声,提高探测脉冲光的相位稳定性;采用时钟同源和时钟非同源两种方式对典型的基于外差相干检测的相位敏感光时域反射系统的声光调制器进行驱动,由信号发生器驱动缠有光纤的压电陶瓷,产生不同频段的扰动信号。实验结果表明:在同一测试条件下,前者在低频段的信噪比、相位解调质量、频率响应方面均优于后者,最小响应频率为0.1 Hz,相对提高两个数量级,降低了系统中低频噪声干扰。该方法易于实现,可与现有的低频性能优化方法或结构兼容,进一步提高系统低频响应性能。
Phase sensitive optical time-domain reflectometry system due to its advantages of distributed optical fiber sensing technology has a high application prospect in low frequency monitoring fields such as distributed hydrophone,fracture micro-seismic detection and natural disaster warning.The problem of different clock source of pulse chopper signal and frequency modulated signal in the system was verified and the influence was analyzed theoretically in this paper.A dual-channel synchronous clock source was designed to generate pulse chopper signal and frequency modulation signal to reduce the random low-frequency phase noise of frequency modulation signal in each pulse repetition period and improve the phase stability of the detection pulse light.The acoustioptic modulator of typical phase-sensitive optical time-domain reflectometry system based on heterodyne coherent detection was driven by clock homology and clock non-homology,a signal generator drives a piezoelectric ceramic wrapped in optical fibers to generate disturbance signals in different frequency bands.The experimental results show that under the same test conditions,the former is superior to the latter in the aspects of SNR,phase demodulation quality and frequency response in low frequency band.The minimum response frequency is 0.1 Hz,which is 2 orders of magnitude higher than the latter,and reduces the interference of low frequency noise in the system.The method was easy to implement and compatible with the existing low frequency performance optimization methods or structures to further improve the low frequency response performance of the system.
作者
于淼
孙铭阳
何禹潼
张崇富
郑志丰
孔谦
Yu Miao;Sun Mingyang;He Yutong;Zhang Chongfu;Zheng Zhifeng;Kong Qian(School of Electronic Information Engineering,University of Electronic Science and Technology of China,Zhongshan Institute,Zhongshan 528402,China;College of Instrumentation&Electrical Engineering,Jilin University,Changchun 130012,China;Zhuhai Pegasus Optoelectronics Technology Co.,Ltd.,Zhuhai 519000,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2022年第5期243-251,共9页
Infrared and Laser Engineering
基金
广东省普通高校青年创新人才项目(2018 KQNCX332)
广东省引进领军人才计划(00201507)
广东省教育厅创团项目(2018KCXTD033)
中山市社会公益科技研究项目(2018 B1021,2020 B2018)
在渝高校与中科院所属院所合作项目(HZ2021014)
重庆市教委重大项目(KJZDM202001401)。
关键词
相位敏感光时域反射
时钟同源控制
随机相位噪声抑制
低频探测
phase sensitive optical time domain reflectometry
clock homology control
random phase noise suppression
low frequency detection
