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阐述了一种基于长周期光纤光栅和Zig Bee组网技术的无线溶液折射率传感网络。整个系统包括了传感节点、路由节点、协调器和中心计算机几个部分。传感节点部分,设计了一种基于强度调制型的低成本的长周期光纤光栅溶液折射率传感器,其中包括了长周期光纤光栅和一种特殊结构的封装。同时,设计了传感器的驱动板,包括激光二极管及其驱动电路、光电探测电路。利用损耗峰两侧近似线性的特性,通过测量单侧损耗峰半峰处固定波长光功率的变化实现了折射率传感。系统搭建了基于Zig Bee的自组网系统,并且实现了实时的多点的溶液折射率监测。测量了折射率为1.3347~1.3418的氯化钠溶液,分辨率为0.0001,最大误差为0.0004,平均误差为0.00015。所述系统提供了一种将光纤传感器应用于无线传感网络的方案,其优势在于可以大面积铺设大量低成本传感器并组网,方便地增减传感节点,实现了大范围、多点、高分辨率的环境监测。
A wireless solution refractive index sensing network based on long period fiber grating and Zig Bee networking technology is described. The entire system includes sensor nodes, routing nodes, coordinator and central computer parts. Sensing node, a low-cost long-period FBG solution refractive index sensor based on intensity modulation is designed, which includes a long-period fiber grating and a special structure of the package. At the same time, the design of the sensor drive board, including the laser diode and its drive circuit, photoelectric detection circuit. The refractive index sensing is achieved by measuring the change of the optical power at the fixed wavelength at the half-peak of the unilateral loss peak using the approximately linear characteristic of both sides of the loss peak. The system is based on Zig Bee’s ad hoc network system, and real-time multi-point solution refractive index monitoring. The refractive index of 1.3347 ~ 1.3418 of sodium chloride solution was measured with a resolution of 0.0001, the maximum error of 0.0004, the average error of 0.00015. The system provides a solution for applying a fiber optic sensor to a wireless sensor network. The advantage of the system lies in laying a large number of low-cost sensors on a large area and networking, conveniently increasing or decreasing sensor nodes, realizing large-scale, multi-point, High-resolution environmental monitoring.