Recent advances in fiber-optic evanescent wave sensors for monitoring organic and inorganic pollutants in water

Abstract Fiber-optic evanescent wave (FOEW) sensors are promising in pollutant detection and evaluation of water quality because of their high resistance to corrosion, smart structure, anti-electromagnetic interference, and low cost. In particular, FOEW sensors have proven very useful for online detection and monitoring of multiple parameters in water. However, these sensors suffer from several challenges such as poor sensitivity and selectivity, and high limit of detection. In this review, we introduce four types of fiber-optic sensors, including biochemical FOEW sensors based on structured optical fibers and fiber gratings, for detection of organic and inorganic pollutants in water. The structure and measurement principles of these sensors are presented. Effective methods to enhance the selectivity, sensitivity, detection limit, and response speed of these sensors are summarized. Finally, an outlook on the future of FOEW sensors in water quality monitoring is discussed.