Carbon-nanotube / Polyvinyl alcohol coated thin core fiber sensor for humidity measurement

A Carbon-nanotube (CNT)/Polyvinyl alcohol (PVA) composite film-coated thin core fiber (TCF) optics sensor is proposed for monitoring relative humidity (RH). The unique Michelson type fiber interferometer sensor consists a short segment of TCF, the tip of which is melted into a convex shape and coated with a hydroscopic CNT/PVA film. The proposed sensor is linearly responsive to relative humidity (RH) beyond the humidity range 70%RH, with maximum sensitivity of −0.4573 dB/%RH. The advantages of this sensor are its compact size, excellent stability and facile fabrication process.