Simultaneous humidity and temperature measurement sensor based on two cascaded long-period fiber gratings

Humidity sensing by tailoring light absorption of SiO2/bromophenol blue (BPB) thin film on optical fiber

“…Over the past few decades, fiber optic humidity sensors have been investigated extensively due to their unique features including resistance to chemical corrosion, immunity to electromagnetic disturbance, potential miniaturization, and distributed installation in networks. [4][5][6] These sensors were modulated in optical characteristics such as amplitude, phase, interference, and other parameters. Particularly, owing to the simple fabrication process and cost-effective signal detection, evanescent wave fiber optic sensors modulated in optical intensity have attracted attention for potential applications in mass-site humidity monitoring.…”