为了精确、 稳定地获得粮仓内大范围的温度分布, 设计了光纤布拉格光栅测温系统。 利用光纤布拉格光栅所测温度与中心波长之间存在线性的关系, 根据光谱线性频移函数获得仓内各位置的精确温度。 其中每个光栅的工作波长相互分开, 经3 dB的耦合器反射后, 再用波长探测解调系统对多个光栅的线性频移进行测量, 即可检测出仓内各处的温度。 实验采用FBG封装的光纤、 LPT-101型光源、 放大处理电路等设备获得采集得到的温度信息。 通过Origin软件画出了被测温度与波长频移的关系图, 同时与传统的测量方法K型热电偶的测量数据进行比较。 实验结果显示, 光纤布拉格光栅测得温度与标准温度更接近, 且抗干扰能力更强, 满足粮仓内大范围温度监测的要求。

In order to obtain the distribution of the temperature in the range of the granary precisely and stably, we designed a temperature measurement system of the fiber Bragg grating. Through the fiber-optic network the system can detect granary temperature in a wide range, and there is a linear relationship between the measured temperature by fiber Bragg grating and the center wavelength, so according to the function of spectrum linear frequency shift it obtained precise temperature in the granary. The working wavelengths of each grating in the system are separated from each other. After reflected by 3 dB coupler, the wavelength detection and demodulation system was used to measure the linear frequency shift of the plurality grating, and the system can get temperature data of everywhere in the granary. The experimental obtained the temperature information by equipments, such as LPT-101 light source, optical fiber with FBG encapsulated, magnification processing circuit, simulation granary, etc. With Origin software the diagram of the relationship between the frequency shift of the measured temperature and wavelength was drawn, and compared with the traditional measuring method of the K-type thermocouple measurement data. Experimental results show that the measured temperature of the fiber Bragg grating is closer to standard temperature, and the anti-jamming ability can meet the requirements of the granary large range temperature monitoring.