Fiber optic Fabry–Perot interferometer based on HA/PVA composite film for humidity sensing

•The proposed sensor uses HA/PVA composite as a novel humidity sensitive material.•The humidity characteristics of the sensors with different mixture ratios of HA/PVA composite are investigated for the first time.•The sensor has a high humidity sensitivity of −233 pm/%RH.•The sensor has a low temperature cross sensitivity of −0.101%RH/°C.•The proposed sensor has compact size, good stability and fast response time.