【作者】 李丽；

【导师】 林玉池；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2007， 博士

【摘要】 光纤光栅作为一种新型光子器件,可制成各种传感器,在传感领域得到广泛的应用。它以其独特的抗电磁干扰、可靠性高、便于实现分布式传感等优势越来越被人们所重视。在军事和民用工程领域具有广泛的应用前景,近年来受到各国有关研究人员的普遍关注。本课题得到教育部博士点专项科研基金项目（20030056017）的资助,主要是探讨光纤光栅传感,特别是位移传感应用中的关键技术问题。论文主要以光纤Bragg光栅（FBG）为研究对象,从光纤光栅的传感特性、位移调谐方法、交叉敏感及解调技术等方面进行了理论和实验研究。论文依据耦合模理论推导了均匀周期光纤Bragg光栅的传输响应特性,对光纤光栅的反射谱进行了数值模拟,研究了光纤Bragg光栅的应变温度传感模型及应变温度交叉敏感的影响,并对消除交叉敏感现象做了详细分析。设计了可消除环境温度影响的等腰三角状悬臂梁敏感结构,有效地将梁自由端位移f的变化转变为等强度梁的应变,实现了微位移的光学测量。基于悬臂梁的线性调谐特性,提出了采用光栅对结构实现光纤光栅位移传感的解调新方法并通过实验进行了验证,结果表明系统的灵敏度为1.2 mV /μm。结合空分复用技术,对光纤光栅位移传感系统中的关键技术进行了分析研究。提出了采用波分复用器和非平衡M-Z干涉仪实现不同光栅Bragg波长变化查询的位移传感系统,设计了以PIC单片机为核心的控制和相位测量装置。通过调谐特性实验和位移传感实验,结果证明系统有效可行,系统传感灵敏度为4.6 rad /nm ,相位测量系统的分辨率为20nε,测量范围大于8mm。利用光纤Bragg光栅对冲击机械动态应变信号的传感检测进行了应用研究。设计了基于相位载波零差法和非平衡M-Z干涉系统的光纤光栅动态应变信号检测系统,通过对标准正弦波形驱动测试实验和实际冲击信号检测实验的数据分析,结果证明检测系统具有良好的重复性,在10kHz的频率范围内,最小能检测的动态应变相对量为10^-4,为光纤光栅水听器的研制进行了前期性探索。更多还原

【Abstract】 Fiber grating is a new optical passive component which can be made novel sensors. It has several distinguished advantages over normal sensors. Fiber grating sensors,which are now widely applied in the fields of the civil and military projects, have been concerned by the researchers worldwide in recent years.The project is from the scientific research fund doctor items (20030056017) of the ministry of education. The main aim of this research was to have a discussion and a basic study on the displacement sensing technique of fiber Bragg grating .The paper aimed at fiber Bragg grating and studied the key technique of the fiber Bragg grating displacement sensoring system. The theory and experiment research on the sensor characteristic, displacement tuning methods, across sensitivity and demodulation technology of fiber grating are processed.The light-wave travel law in the fiber Bragg grating and the sensing model of even cycle fiber Bragg grating was studied in this paper. According to the theory of coupling the cycle transmission characteristic of FBG is deduced. The refective chart of fiber Bragg grating is numeric simulated. The model of strain and temperature sensing and the cross sensitivity of strain and temperature was studied, in addition the phenomenon how to delete across sensitivity is analysed.An isosceles triangle cantilever sensitive construction is designed which can delete the influence of environmental temperature. The cantilever sensitive construction can turn the change of micro-displacement into the strain of the equal intension cantilever. Then the optical measurement of micro-displacement is realized. The novel demodulation method of fiber Bragg grating displacement sensor is proposed which make use of the linearity tune characteristic of the equal intension cantilever. The experiment result shows the sensitivity of the system is1.2 mV /μm.Combining the multiplexing technology, the key technique of the fiber grating displacement sensing system is analysed. The wavelength division multiplexer is adopt to realize the demand of the change of different fiber Bragg grating wavelength. The fiber grating displacement sensing system is built on the demodulation theory of non-balanced Mach-Zehnder interferometer. The controlling and phase measuring system with PIC single-chip is designed. The experimental results of tune characteristic and displacement sensing shows the sensitivity of the system is 4.6 rad /nm and the measuring range exceeds 8mm . The fiber Bragg grating can be used to measure dynamic strain in impact machine system. So a system of dynamic strain measuring system with Fiber Bragg Grating based on the phase generated carrier and unbalanced M-Z interference system was designed, which the cut-off frequency is 10 kHz. The standard sine wave driving measuring experiment and the impact signal measuring experiment were made to validate the system is workable. The prophase research of fiber Bragg grating hydrophone is prepared.更多还原