Nanostructured coating of graphene nanoparticles deposited onto a cladding etched no-core optical fiber for...

We report on a temperature sensor based on an optical fiber with nanostructured cladding fabricated by graphene nanoparticles (G-NPs) deposited onto a chemically etched no-core fiber (NCF). The basic structure of this sensor comprises a single-mode-no-core-single-mode (SNCS) fiber section concatenation. The sensing head is the NCF segment where the modal interference is highly sensitive to temperature variations. The influence of the NCF diameter on the sensitivity of the sensor has been investigated. The obtained results revealed that the sensor with an etched NCF diameter of 60 µm coated with G-NPs embedded in polyvinyl alcohol exhibits a maximum sensitivity of -0.104nm/^∘C in the temperature range of 25-235°C, which is approximately six times higher than that of the basic structure without coating. To the best of our knowledge, this is the first demonstration of a temperature sensor based on an etched NCF coated with graphene-polyvinyl alcohol thin film.