给出了基于宽谱光源问讯的具有波长标定功能的多模光纤温度传感器理论分析,指出光谱中凹陷所对应的特征波长位置是由多模光纤中激励起的多个传输模式再次耦合到引出单模光纤中进行干涉决定;特征波长由多模光纤的芯径、长度、纤芯和包层折射率决定。利用提出理论对光源光谱ASE的光谱范围中出现的特征波长的个数进行了分析模拟,并优化设计了只出现一个特征波长的多模光纤温度传感器,制作了三个长度分别约为4 cm,5.5 cm和10 cm的只有一个特征波长的多模光纤温度传感头,利用毛细玻璃管进行了封装, 并利用分辨率为0.01 nm的光谱分析仪进行了温度测量实验,发现温度与特征波长漂移的线性关系约为13 pm/℃。

The theory analysis and experiments of multimode fiber (MMF) temperature sensors with the capability of wavelength encoding are presented. The analysis based on multimode-interference predicts the characteristic dip-wavelength positions of the MMF sensor according to the radius, the length and the refraction index of the MMF. It is used to optimize the sensor to produce only one characteristic dip-wavelength for a MMF temperature sensor in the wavelength range of a broadband source ASE. Three MMF temperature sensor heads with the length of 4 cm, 5.5 cm and 10 cm, packaged by a micro-silicon-tube, are fabricated and tested based on the ASE source with the wavelength range from 1525 nm to 1565 nm and optical spectral analyzer with the resolution of 0.01 nm separately. MMF temperature sensors with only one dip-wavelength and the temperature sensitivities ～13 pm/℃ are gained, which agrees with the theoretical analysis well.