Optical fiber sensors for measurement of heavy metal ion concentration: A review

With the increasing of water pollution problems, detection of heavy metal ion concentration in water environment becomes significant. Optical fiber sensor, with its particular advantages of small-size, anti-electromagnetic interference, chemical inertness, remote and real-time monitoring ability, has become an ideal platform for detection of heavy metal ion concentration. In this paper, we briefly review the current research progress of heavy metal ion sensors based on optical fiber technology. Five main measurement methods are described, including optical absorbance method, fiber grating method, modal interference method, plasmonic method, and fluorescence method. The sensing mechanisms, sensing structures, sensing materials, and sensing characteristics of different kinds of measurement methods are introduced and summarized. Furthermore, the advantages and disadvantages of each measurement method are analyzed. Finally, the future development directions of optical fiber heavy metal ion sensors are also discussed.