Humidity Sensor Based on Etched Optical Fibers Coated With Graphene Composite

In this research, optical humidity sensors based on etched-optical fibers coated with graphene Oxide (GO), silica gel (Sg) and a silica gel modified with GO (GSg) was studied. Their humidity sensing behavior was investigated by variation of relative differentiation of attenuation (RDA) in the presence of relative humidity (RH). As the results showed, etched fibers coated with Sg and GSg are highly capable of humidity sensing. However, a Sg- coated sample is not useful as humidity sensor related to sample coated by GSg because its RDA lacks a one-to-one correspondence with RH. As it was also found, the sensitivity of a GSg-coated sample is higher when the RH is below 40% and its repeatability is considerable.