半导体吸收型光纤温度传感器线性度分析

良好的线性度能提高有效测量区域的精度。为提高半导体吸收型光纤温度计的测量精度和范围, 根据光源发射谱应能覆盖半导体的吸收边原理, 利用在常温下发射波长为850nm的光源, 着重讨论了半导体吸收谱线和光源辐射光谱的相互关系对温度测量线性度的影响。通过对GaAs材料的吸收谱随光子能量变化规律的理论分析, 以及光源输出光强随温度变化的实验数据的分析, 将温度线性测量范围从20 ℃～80 ℃拓宽至10 ℃～90 ℃; 从光源的发射光谱特性和选用半导体材料的吸收谱线两个方面着手, 得出提高光源输出功率可相应拓宽温度的线性测量范围的结论, 为半导体吸收型光纤温度传感器的高精度测量提供参考。

Linearity Analysis of Fiber-Optic Temperature Sensor Based on Semiconductor Optical Absorption

A good linearity of measuring curve can improve the resolution of valid measure-area. The optical absorption edge is 850nm under the temperature of 25℃. The emission spectrum of the light source used with the sensor should overlap on both sides of the optical absorption edge. The displacement of this edge induced by temperature changes modifies the fraction of light that falls into the absorption band, meaning that transmitted intensity will change. From several equations, the reflected light intensity is closely connected with the temperature of detected object. As the temperature climbs up, the ultimate output light intensity falls down nonlinearly. After that, we have proposed the feasibility to broaden the range of measurement from 20 ℃～80 ℃, as many references discussed, to 10 ℃～90 ℃. Therein two groups of curve about reflected light intensity induced by temperature through the computation of Matlab, three groups of curve on output intensity according to temperature variations, three groups of curve about detected voltage changes under different incident light intensities are concluded. From above, four valuable conclusions are brought into being.