U-shaped PCF humidity sensor coated with polyvinyl alcohol

Relative humidity is an important parameter. The detection and control of humidity is of great significance for agriculture, new material development, biological research and protection, health services and other industrial and agricultural production. In this paper, a micro-nano photonic crystal fiber humidity sensor with U-shaped structure is proposed. Due to its probe structure, this structure can more conveniently realize the detection work. The experiment shows that this kind of optical sensor has good linearity in the humidity range of 42–62[Formula: see text]RH%, and can realize the humidity sensing of 27.62[Formula: see text]pm/RH%. The detection range of this kind of sensor is relatively wide, and can realize the optical fiber sensing in a larger humidity range.