涂覆层对长周期光纤光栅液体浓度传感特性的影响

Coating's Effect to Solution Concentration Sensing Characteristics of Long Period Fiber Gratings

长周期光纤光栅是一种性能优良的光纤无源器件,在光纤传感方面用途广泛。利用高频CO2激光器在涂覆层没有剥除的光纤上刻写了长周期光纤光栅,进行了液体浓度传感特性实验研究。实验结果表明:带涂覆层的长周期光纤光栅的谐振波长与峰值损耗对液体浓度变化不敏感,涂覆层可以缓冲外界环境折射率变化对长周期光纤光栅特性的影响。若考虑传感应用中的机械强度要求,在相同条件下带涂覆层的长周期光纤光栅更适合作为对环境折射率不敏感的传感元件使用。

Long period fiber gratings（ LPFGs） is a kind of high performance fiber optic passive devices,and it was widely applied in optical sensing. LPFG had been written by high frequency CO2 laser,and the solution concentration sensing characteristics experiments had been finished. The experimental results showed that the resonant wavelength and peak losses of coated LPFG was not sensitive with solution concentration changing. But the coatings could buffer the environment refractive index change on the influence of the characteristics of LPFG. If considering the mechanical strength request at application,the coated LPFG was more suitable to the environment refractive index insensitive sensing device than the uncoated LPFG at the same condition.