Radiation absorption creates electronic excited states that are trapped by localized defects for extended periods of time. Optical fiber sensors (OFSs) have emerged as essential tools in the monitoring of physical, chemical, and bio-medical parameters in harsh situations due to their high sensitivity, electromagnetic interference (EMI) immunity, and long-term stability. However, the current literature contains. Jose Miguel Lopez-Higuera: Handbook of Optical Fiber Sensing Technology, John Wiley & Sons, 2002. This section provides a detailed look at fiber optic sensors. What Is a Sensor? Learn all about the principles, structures, and features of eight sensor types according to their detection principles.