Graphene Oxide Based-Tapered Optical Fiber Sensor for Hydrogen Sensing Application

Hydrogen (H₂) is the most common element on earth and is found mainly with oxygen in water and hydrocarbons. Hydrogen has applications in many industries. It is used in liquid to propel rockets, cryogenic research in superconducting studies, and oil refining. This paper aims to develop tapered optical fiber sensor coated with Graphene Oxide (GO) for H₂ sensing application. The optical fiber was fabricated by tapering a standard optical fiber via a cost-effective and simple tapering technique. The author has a varied parameter from waist diameter to 20 μm with a fixed length of 10 mm and an up / down taper of 5 mm. Micro-nano characterization techniques such as FESEM, EDX, AFM, and XRD were utilized to obtain detailed structural properties of these nanostructures and fundamentally understand their functions concerning optical sensor performance. The responses of the developed sensor toward H₂ were measured through the change in absorbance within the concentrations of 0.125% – 2.00% in synthetic air. The developed sensor indicated high sensitivity toward the change in H₂ concentration at 100 ^oC. The observed response and recovery time for 2.00% H₂ were calculated as 2 minutes and 11 minutes, respectively. The developed optical fiber sensor achieved high selectivity and excellent stability toward H₂ gas upon exposure to other gases such as NH₃ and CH₄.