A fiber refractive index sensor based on porous alumina is fabricated by pasting porous alumina film with 42.36μm on single mode fiber tip using the UV-cured adhesive. Experimental results show that the proposed sensor has a very high correlation with glycerine concentration (0.0%~80.0%) with correlation coefficient of 99.771%. Its sensitivity and resolution was measure to be 99.771%, 154 nm/RIU and 1×10-4 respectively when the refractive index changes from 1.333 to 1.443.
A fiber optic relative-humidity sensor with a low-fineness Fabry-Perot cavity is proposed and demonstrated. Manufactured by e-beam evaporation, the Fabry–Perot cavity composed of five-layer dielectric oxides has columnar and porous structures, which is sensitive to relative-humidity change of environment. Experimental investigation shows that the proposed sensor exhibits a sensitivity of 0.42 nm/%RH when the ambient relative humidity changes from 15.2%RH to 74.3%RH.