基于乙醇填充的光子晶体光纤温度传感器

提出一种具有独立探头的反射式高双折射光子晶体光纤环镜结构,此结构利用乙醇的热光效应对光子晶体光纤双折射线性调制,双折射的改变引起Sagnac干涉系统光程差的变化,并导致光谱强度在某一温度区间随温度线性变化,实现了温度的高灵敏度测量.此结构克服了传统的环内结构易受外界扰动的缺点,并且使其在实际应用中搭建分布式传感系统成为可能.实验验证了乙醇的折射率随温度的线性变化规律,灵敏度为4.45e-4/℃;验证了填充乙醇后光子晶体光纤双折射与温度的变化规律,灵敏度为0.015 625/℃;验证了在20~40℃之间,输出光强随温度的变化规律,灵敏度为0.003 1 m W/℃.利用琼斯矩阵理论论证了干涉光谱的形成机理,得到干涉谱方程.

Temperature Sensor with Photonic Crystal Fiber Filled with Ethanol as Probe

A high birefringence photonic crystal fiber(HiBi-PCF) loop mirror structure was proposed with a reflective independent probe， in which the thermo-optic effect of ethanol was used to modulate linearly photonic crystal fiber birefringence. The Sagnac interference optical path difference was changed by the birefringence variations， resulting in the linearly changes of spectral intensity in a certain temperature region. Based on the above principle， high sensitive temperature measurement could be implemented. The structure improves the shortcoming of the traditional ring inner structure affected by external disturbance， and makes it possible to build a distributed sensing system in practical application. The experimental results showed that the refractive index of ethanol changes versus the measured temperature linearly with the sensitivity of 4.45e-4/℃. The birefringence change rule of ethanol-filled HiBi-PCF with temperature was also indicated with the sensitivity of 0.015625/℃. In addition， the change rule of output light intensity with temperature between 20~40℃ was tested with the sensitivity of 0.0031mW/℃. The formation mechanism of interference spectrum was demonstrated by using the Jones matrix theory， with the interference spectrum equation obtained.