Sensing properties of graphene-oxide-functionalized single-mode–no-core–single-mode fiber structure

A series of single-mode–no-core–single-mode (SNS) optical fiber sensing structures with different thicknesses of graphene oxide (GO) coating were fabricated and tested with glycerin and magnetic fluid solutions. Owing to the two-dimensional network structure of GO, the GO coating improved the performance of the sensor for the structure immersed in glycerin solution. The highest refractive-index (RI) sensitivity (in RI units or RIU) of the GO-coated sensor is 496.823 nm/RIU. However, the GO coating reduced the magnetic field sensitivity of the sensor for the structure immersed in magnetic fluid solution. The mechanism of enhanced RI sensitivity and decreased magnetic field sensitivity is clarified.