光电缆的分布式温度传感网络

提出增加一根光纤光栅与光电缆绕制在一起，用于监测电缆中的实时温度。采朋有限元分析方法，建立了光电缆温度场模型。使用可调谐脉冲激光作为系统光源，在一条光纤上刻制多个相同中心波长的布拉格光栅，即采用全同光栅作为系统的温度传感器，当光电缆线路中温度发生异常时，反射回来的光栅中心波长发生偏移，通过检测反射光中心波长发生的偏移量可以确定光栅温度变化的大小。不同位置的光栅返回光信号所需的时间不同，通过检测和计算光返回的不同时间，可以计算出发生温度变化的光栅位置。实验结果表明，光栅的温度敏感性可以达到11．4pm／℃，光栅的测量温度与实际温度的误差在3％范围内。

Distributed Temperature Sensing Network Based on the Optical Cable

In this paper based on the optical cable, a method was presented that increasing a Fiber Bragg Grat- ing together with the optical cables, which could be used for monitoring the cable real-time temperature. Finite- element method was used to establish the temperature field model of optical cables, and using a tunable laser as a system source, engraving many the same center wavelength of the fiber Bragg grating in a fiber, that was to say using the whole grating as a system temperature sensor. In Optical cable lines when the temperature is abnormal, the reflected grating center wavelength will shift. By detecting the center offset of the reflected light could determine the size of the grating temperature change. Grating at different positions reflected optical signals need different time. By detecting and calculating the interval time of reflected light, the location and the temperature of the grating whose temperature has changed will obtain. Experimental results showed that grating temperature sensitivity rose at 11.4 pm/℃. The deviation between the measured temperature and the actual temperature was within 3% range.