Slot fiber optic sensors are widely used for electronic component counting, small part position detection, product dimension measurement, and automatic assembly positioning. The optical fiber consists of the core and the cladding, which have different refractive indexes. The light beam travels through the core by. A fiber optic sensor measures a physical quantity by modulating the intensity, spectrum, phase, or polarization of light traveling through the optical fiber system. 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"). Fibers have many uses in remote sensing. Depending on the. Radiation absorption excites an orbital electron to a higher energy level. Heating the material enables the trapped states to interact with phonons and decay into lower-energy. Optical sensors are one of the most popular sensor types in industrial automation.