Design and construction of Humidity Sensor by Thinned Optical Fiber with Graphene Coating

In this study, graphene synthesized by Hammer's method and qualify by XRD, TEM, SEM, FTIR and Raman analysis. Then colloids of graphene with different densities are coated on the etched single mode optical fiber. To investigate the humidity sensing of them, the relative differentiation of attenuations (RDA) in the presence of relative humidity (RH) is measured at two standard wavelengths telecommunication (1310 nm and 1550 nm). Results show diluted graphene solution with high ratio of One-layer to multi-layer improves the humidity sensing of etched optical fiber relative to others. Also, 60 minute etching of optical fiber in acid cause to 43μm diameter of it, have higher response to humidity.