Optical fibre based humidity sensor using Co-polyaniline clad

A humidity sensor of nanostructure Co dispersed in polyaniline deposited as a clad, having quick response of 8 s (20–95%RH) and recovery time of 1 min (95–20%RH) on fibre optical waveguide, is reported, in the range of 20–100%RH. The length and thickness of the clad is optimized for better performance on a commercially procured plastic optical fibre whose original cladding is removed. The sensor response is reproducible, repeatable and fully reversible. The clad length is optimized to10 mm with thickness 10.38 μm, exhibits the best results. Material characterization is done using SEM, XRD and FTIR.