提出了一种基于在折射率引导型光子晶体光纤(PCF)中填充高折射率温度系数液体的新型折射率型光纤温度传感器。通过建立理论模型, 设定入射波长和材料参数及完美匹配层边界条件, 采用全矢量有限元法对六角形结构排列的折射率引导型光子晶体光纤的温度特性进行了分析。研究表明, 在空气孔中填充液体乙醇, PCF模场分布随着温度变化明显, 其有效折射率和限制损耗都随着温度升高而减小。相同的孔间距, 占空比越大, 输入波长越长, 有效折射率和限制损耗受温度影响越大。当波长为1500 nm, 占空比为0.7, 温度从-20 ℃升至70 ℃时, 限制损耗从3.5×102 dB/m减小到22 dB/m。

A novel temperature sensor of photonic crystal fibers (PCF) based on liquid ethanol filling with refractive index sensitive to temperature is proposed. The temperature properties of the sensor were investigated by the full-vector finite element method with a perfectly matched layer. Theoretical calculations show that filling the air-holes of a PCF with ethanol will enhance the temperature influence on the mode field. Both the effective refractive index and the confinement loss decrease with increase of temperature. After filling the liquid ethanol, the mode field infiltrates more through the cladding of fiber as the wavelength increases, and becomes more sensitive to temperature. Under the condition of the same hole spacing, the larger the duty ratio and the longer the input wavelength are, the stronger are the dependence of the effective refractive index and the confinement loss on temperature. The effective refractive index basically reduces linearly when temperature increases. When the wavelength λ=1550 nm, hole to hole spacing Λ=2.3 μm and duty ratio d/Λ=0.7 (d represents the hole radius), the confinement loss reduces from 3.5×102 dB/m to 22 dB/m as the temperature changes from -20 ℃ to 70 ℃.