WATER QUALITY MONITORING USING REFRACTIVE INDEX SENSING E-FBG SENSORS

Abstract

The need to protect the environment has stimulated the development of numerous analytical techniques for detecting pollutants in natural ecosystems, including methods for determining nitrate concentrations in source water. In this context, the present study introduces an experimental approach for water quality assessment based on etched fiber Bragg gratings (e-FBG). Specifically, the method relies on monitoring the shift in the Bragg wavelength, which occurs as a result of variations in the refractive index of water caused by changes in its chemical composition. Moreover, we proposed a water quality monitoring strategy employing e-FBG sensors, which provides high sensitivity to fluctuations in the optical properties of the surrounding medium. The applicability of the proposed sensor is demonstrated through the detection of low concentrations of nitrates in aquatic environments. The e-FBG sensor exhibits several notable advantages. In particular, it offers high resolution for wavelength shift detection, a high optical signal-to-noise ratio of 40 dB, and a narrow bandwidth of 0.02 nm, which collectively enhance the accuracy and reliability of peak wavelength measurements. Furthermore, the sensor supports optical remote sensing, making it suitable for real-time environmental monitoring. Therefore, the experimental results strongly suggest that the proposed e-FBG sensor holds significant potential for pollutant detection in practical field applications.