光纤光栅波、空分复用传感网络有源查询技术

【作者】 刘士奎；

【导师】 余有龙；

【作者基本信息】 黑龙江大学 ， 物理电子学， 2005， 硕士

【摘要】 提出一种利用光纤光谱仪观察宽带光源通过干涉仪的干涉谱计算臂长差大小的方法,并利用最小步长为0.1μm的微动平台拉伸光纤Mach-Zehnder干涉仪进行了验证。实验证明了此方法的可行性,精度达20μm,完全能满足制作解调用光纤干涉仪的需要。 结合干涉解调对干涉仪的要求,制作了臂长差为3.19mm的光纤Michelson干涉仪,并将干涉仪短臂的中间小部分粘贴在压电陶瓷上,成为扫描干涉仪。为避免外界环境对干涉仪的干扰,将干涉仪和压电陶瓷封装在密闭的金属盒内,同时为避免扫描过程中压电陶瓷产生的热量对解调结果的影响,采用了温度控制系统对整个干涉仪进行了控制,温度控制系统在工作40分钟后金属盒内温度可以达到稳定状态,此时温度波动小于0.02℃。 利用1×4光开关的光路选通作用以及可调谐光纤F-P滤波器的带通滤波特性,对4×10光纤光栅组成的传感网络成功进行了查询。利用全光纤扫描Michelson干涉仪对传感信号进行了高分辨率解调,系统的传感灵敏度为1.6749°/με,在误差允许范围内与理论值1.6855°/με基本相符,分辨率为5.9 nε。选择某一传感光栅后,反馈控制系统保证系统具备自动追踪感测信号的能力。更多还原

【Abstract】 A simple method based on broadband source and optical spectrum analyzer to measure the optical path difference (OPD) of a fiber interferometer was described in this paper. Sticking one arm of an all fiber unbalanced Mach-Zehnder interferometer on a translation stage, when the arm was being stretched, and then the different OPD can be got. The method was proved to be effective and the resolution of the OPD was 20 μm, which was enough to meet the demands of making interferometer used in the demodulation of fiber Bragg grating (FBG).An all fiber unbalanced scanning Michelson interferometer with the OPD 3.19 mm was made. In the case of elimination of environmental interference, the interferometer was put in a metal obturator. In the case of elimination of the heat generated by the PZT when scanning, a temperature controller was used to control the temperature inside the obturator. The temperature fluctuation that less than 0.02℃ was got after the temperature controller had worked 40 minutes.A spatial/wavelength division multiplexed 4×10 FBG sensor array, acted as the reflector of a ring cavity fiber laser, was interrogated by employing a 1 X 4 optical switch and a tunable F-P filter. Demodulation was achieved by using the unbalanced Michelson scanning interferometer that transform the wavelength-shift signal induced by the measured strain into phrase-shift signal. The sensor sensitivity of the system was demonstrated to be 1.6749° /με, which agreed with the theoretical value of 1.6855° /με. A feedback subsystem was introduced to make the system track the measuring FBG automatically.更多还原