Development and Experimental Analysis of Titanium Dioxide (TiO2) Coated Etched Fiber Bragg Grating Sensor for Chemical Sensing

This paper reports on a single-mode etched fiber Bragg grating (eFBG) sensor coated with 99.99% pure titanium dioxide (TiO
₂
) having enhanced sensitivity for sensing of industrial chemicals such as glycerine. Cladding of grating section of single-mode fiber has been partially etched to maintain the integrity of fiber structure, yet high sensitivity is achieved by the deposition of a thin film of TiO
₂
coating. Comparisons of sensitivities achieved with and without coating have been shown. The metal oxide coating helps enhance sensitivity by nearly 20% by increasing the interaction of the evanescent field leaking into analyte. The proposed sensor has recorded a maximum sensitivity of 11.9 nm/RIU, which is more than any other single-mode etched FBG sensor delineated so far for sensing of glycerine. In the presented paper, the characterization of coating material with X-ray diffraction (XRD), and of the resultant sensor with Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM) has also been carried out as part of experimental analysis.