Uncladded fiber bragg grating etched with nitric acid for glucose concentration measurement

In this study, we present an investigation of uncladded fiber bragg grating (FBG) as a chemical sensor towards glucose in an aqueous solution with various concentrations from 0-60 wt%. Uncladded fiber bragg gratings have been etched with nitric acid (HNO3) therefore acting as a sensing element. Two measurement methods consisting of optical spectrum analyzer (OSA) and spectrometer systems were performed. We compare which method shows the best response from uncladded FBG as a glucose concentration sensor. The measured parameter is the wavelength shift in OSA system, while in spectrometer system is optical intensity. It was found that the uncladded FBG exhibits the response towards glucose concentration variations for both measurement methods. The results show that the OSA method is better because the sensitivity is larger. This sensor can be developed further to be coated by some sensitive materials to enhance its performance.