Investigation of the humidity sensing of etched optical fibers coated with a graphene oxide/silica composite

Abstract

Humidity sensing 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 the relative differentiation of attenuation (RDA) in the presence of relative humidity (RH) by the Optical Loss Test Set. The results show that etched optical fibers coated by Sg and GSg have a high RDA in the presence of RH. Also, GO shows a low RDA value and high variance. However, the pristine Sg needs to take time to recover when saturated with moisture, so it does not have a fast and repeatable response. Results show that modification of a silica gel by GO (GSg) succeeds in solving their defects and makes it capable of humidity sensing usage. Their RDA is relatively high, it has a rapid response, one-to-one correspondence with RH, and it could operate in a wide range of humidity. Additionally, their good repeatability, high sensitivity, and low variance is suggestive of their accuracy.