Principles and Status of Actively Researched Optical Fiber Sensors

This chapter reviews the current status of optical fiber sensorsAs soon as optical fibers were developed, it was concluded that they could also be used for sensors. Therefore, the history of research in optical fiber sensors is almost as old as the history of optical fiber communication research. Although optical fiber sensors have not experienced the dramatic commercial success of optical fiber communications, they have been continuously and extensively studied. Optical fiber sensors have unique advantages, such as high sensitivity, immunity to electromagnetic interference, small size, light weight, robustness, flexibility, and the ability to provide multiplexed or distributed sensing. Some fiber grating sensors have been commercialized for the health monitoring and oil industries. There are other rather mature optical fiber sensor technologies such as optical time-domain reflectometers (OTDRs), fiber optic gyroscopes (FOGs), and optical fiber current sensors. New ideas are continuously being proposed and tested, not only for various traditional measurands such as strain, temperature, and pressure, but also for new applications such as biosensors or medical imaging, including optical coherence tomography.