光纤F-P腔高灵敏加速度传感器理论模型研究

Research on theoretical model of fiber optic F-P cavity acceleration sensor with high sensitivity

摘要:

以提高光纤波长复用型加速度传感器的灵敏度为目标,分析光纤布拉格光栅(fiber Bragg grating,FBG)加速度传感器的增敏思路,阐明FBG加速度传感器灵敏度的增敏瓶颈和固有制约因素,提出波长复用型光纤法布里-珀罗(Fabry-Pérot,F-P)加速度传感器物理模型,理论研究其加速度传感原理,推导加速度传感器谐振频率和灵敏度的解析表达式,深入分析系统的结构体刚度、干涉级次、腔长对加速度传感器灵敏度和谐振频率的影响因素,并对比分析在不同系统刚度下FBG和F-P加速度传感器的灵敏度响应特性。由于灵敏度与谐振频率相互制约,进一步引入品质因子对比分析FBG和F-P加速度传感器的综合性能。在谐振频率为205 Hz时,传感器灵敏度高达198 nm/G,比基于FBG的传感器灵敏度理论上高出约2个数量级,并提出F-P型加速度传感器波长复用方案。理论分析表明F-P型加速度传感器与FBG型相比具有独特的优势,为光纤型加速度传感器的增敏和波长复用提供了新思路,并奠定理论基础。

Abstract:

Aiming at improving the sensitivity of optical fiber wavelength multiplexing acceleration sensor,the sensitization idea of fiber Bragg grating (FBG) acceleration sensor is analyzed and the sensitivity bottlenecks and inherent constraints of FBG acceleration sensor are clarified.The physical model of wavelength multiplexing fiber Fabry-Pérot (F-P) acceleration sensor is proposed,the principle of acceleration sensing is researched theoretically,and the analytical expressions of the resonance frequency and the sensitivity of the sensor are derived.The influence factors of structural stiffness,interference order,and cavity length of the system on the sensitivity and resonant frequency of the sensor are analyzed in depth,and the sensitivity response characteristics of the FBG and F-P acceleration sensors under different system stiffness are compared and analyzed.Because sensitivity and resonant frequency limit each other,furthermore,the figure of merit is introduced to compare and analyze the comprehensive performance of the FBG and F-P acceleration sensors.When the resonance frequency is 205 Hz,the sensor sensitivity is up to 198 nm/G,higher than FBG sensor sensitivity about 2 magnitude theoretically,and put forward the F-P type acceleration sensor wavelength multiplexing scheme.The theoretical analysis results show that the F-P type acceleration sensor has unique advantages,compared with the FBG type,which provides a new idea for the sensitization and wavelength multiplexing of the optical fiber type acceleration sensor,and lays a theoretical foundation.