A fiber optic sensor measures a physical quantity by modulating the intensity, spectrum, phase, or polarization of light traveling through the optical fiber system. It's a device that converts light rays into electronic signals. Jose Miguel Lopez-Higuera: Handbook of Optical Fiber Sensing Technology, John Wiley & Sons, 2002. P 603 Radiation absorption excites an orbital electron to a higher energy level. Think of it like a photoresistor, which changes its resistance based. A fiber-optic sensor is a sensor that uses optical fiber either as the sensing element ("intrinsic sensors"), or as a means of relaying signals from a remote sensor to the electronics that process the signals ("extrinsic sensors"). Depending on the. We present here the recent advance in exploring new detection mechanisms, materials, processes, and applications of fiber optic sensors. The basic working principle is that when the light signal passes through the optical fiber, parameters such as light intensity, wavelength, and phase will be affected by the. The fiber optic sensor has an optical fiber connected to a light source to allow for detection in tight spaces or where a small profile is beneficial. The optical fiber consists of the core and the cladding, which have different refractive indexes.