基于倾斜光纤光栅的相对湿度传感器

提出了一种基于倾斜光纤光栅(TFBG)的包层上覆盖着聚乙烯醇(PVA)的空气相对湿度传感器,成功实现了对相对湿度在20～98%RH范围内的监测。研究发现,TFBG的透射功率在20～74%RH和74～98%RH2个相对湿度区域内分别呈现不同的线性变化,敏感度分别为2.52 dBm/%RH和14.95 dBm/%RH,并且在高湿度区有更高的敏感性。

Tilted fiber Bragg grating used for relative humidity sensor

A relative humidity(RH) sensor based on tilted fiber Bragg grating(TFBG) is designed by utilizing polyvinyl alcohol(PVA) as the sensitive cladding film.RH increasing in the PVA coating will result in the reduction of refractive index.Due to the TFBG′s sensitivity to ambient refractive index,the spectral properties of PVA coated TFBG are modified under exposure to different ambient humidity levels ranging from 20% RH to 98% RH.The transmission power of TFBG has different linear behaviors for two different humidity ranges(20%-74% RH and 74%-98% RH).And the sensitivity for each humidity range reaches as high as 2.52 dBm/%RH and 14.947 dBm/%RH,respectively.Combining the advantages of optical fiber grating and PVA as a smart material,this design involves simple configuration,low cost,compactness,small degree of hysterisis,good repeatability,stability and wide dynamic sensing range as well.Therefore,the sensor could be applied in fast RH detection for normal as well as harsh humidity environments.