摘要
近年来,基于受激布里渊散射的分布式光纤传感技术已广泛应用于土木结构健康监测、灾害预警、国防安全等诸多领域,振动等动态参量的实时传感和精准检测已成为备受瞩目的研究热点.本文提出一种基于增益开关调制和双斜坡辅助的混沌布里渊光相关域分析传感技术,实现高精度、大范围动态应变监测.首先,理论分析了单斜坡辅助系统中混沌激光固有的时延特征和功率随机波动特性对测量精度的影响和限制;然后,利用增益开关调制产生48.6 dB的高消光比脉冲,使得混沌信号时延旁瓣和非零基底诱发的噪声场被大幅抑制,仿真结果表明声波场信噪比提升3.31 dB,实验测得混沌布里渊增益谱信号背景噪声比提升1倍,动态应变测量精度由±40.2μe提高至±23.1μe;最后,利用双斜坡辅助技术,消除混沌激光固有功率波动的影响,动态应变测量精度进一步提升至±8.1μe,系统稳定性良好,且动态范围仍保持800μe,为现代传感网络的高精度、大范围动态应变监测提供了一种新的解决方案.
Nowadays,distributed dynamic sensing technology based on stimulated Brillouin scattering has been widely employed in civil structure health monitoring,disaster warning,national defense,etc.In this paper,we propose and experimentally demonstrate a novel Brillouin optical correlation-domain analysis based-on gainswitch modulation and dual-slope assisted method for achieving high-accuracy large-range dynamic strain measurement.In single-slope assisted chaotic Brillouin sensing,the measurement accuracy of dynamic strain is deteriorated by the inherent characteristics of time delay signature and power stochastic fluctuations.First,the mechanism behind the acoustic field deterioration and principle of background noise suppression are analyzed theoretically.Then,the chaotic continuous pump light is modulated into pulsed light with a higher extinct ratio of 48.6 dB,where the electro-optical modulator is replaced by a gain switch.And thus,the noise peaks,induced by the secondary peaks and irregular basal oscillations of chaotic auto-correlation curve,are greatly restrained.Comparing with the electro-optical modulator-based system,the signal-to-noise ratio of stimulated Brillouin acoustic field is increased by 3.31 dB in simulation and the signal-to-background ratio of Brillouin gain spectrum is doubled in experiment.Consequently,the measurement accuracy of dynamic strain is improved from ±40.2μe to ±23.1μe and the relative error decreases from ±5.0% to ±2.9% in single-slope assisted system based-on gain switch modulation.In addition,a dual-slope assisted method is inspired to eliminate the detrimental effect caused by the intrinsic power fluctuations of chaotic laser.A verification experiment is preconducted that the dynamic strain could be correctly interrogated although a wide range pump power variation has been manually applied.The measurement accuracy is ultimately enhanced to ±8.1μe and the relative error is ±1% correspondingly,implying a higher stability.The dynamic range of this proposed system is retained at 800μe,which is approximately 5 times as large as the dynamic range of the traditional dual-slope assisted configurations.The 4-cm spatial resolution along 30-m FUT is also investigated and consistent with the result obtained previously.A larger measurement range and a higher vibration frequency would be further explored by using the multi-slope assisted method and piezoelectric ceramic oscillator respectively.The superior slopeassisted chaotic Brillouin optical correlation-domain analysis will provide a new solution for the accurate positioning and real-time monitoring of dynamic parameters in modern industry.
作者
王亚辉
赵乐
胡鑫鑫
郭阳
张建忠
乔丽君
王涛
高少华
张明江
Wang Ya-Hui;Zhao Le;Hu Xin-Xin;Guo Yang;Zhang Jian-Zhong;Qiao Li-Jun;Wang Tao;Gao Shao-Hua;Zhang Ming-Jiang(Key Laboratory of Advanced Transducers and Intelligent Control System,Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024,China;College of Physics and Optoelectronics,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第10期51-60,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:61527819,61875146)
山西省重点研发计划(高新领域)(批准号:201903D121177,201803D121064)
山西省“三晋学者”特聘教授(专家)支持计划(批准号:201617)资助的课题.
关键词
混沌激光
动态应变传感
斜坡辅助
布里渊光相关域分析
chaotic laser
dynamic strain measurement
slope assisted
Brillouin optical correlation-domain analysis
