A novel optical fiber relative humidity sensor with optimized parameters

We report a novel fiber optic relative humidity sensor based on the evanescent wave absorption spectroscopy. A comprehensive study of the sensor was made in terms of performance optimization against various parameters, which affects the sensor response and sensitivity e.g. film composition, film thickness, fiber core diameter and the sensor geometry. The sensor was compared against a commercially available relative humidity sensor and was found to be sensitive to relative humidity ranging from similar to1.6% to similar to92%. We found that the sensor was having a very fast response to the relative humidity, and was fully reversible, repeatable with an extremely large dynamical range.