Fiber optic-based temperature sensors can support a wide temperature range, from cryogenic temperatures to high temperatures up to 900°C. As the optical fiber is inert to most of the chemicals, the sensors have a high tolerance towards chemical reactivity and. Fiber-optic high-temperature sensors are gradually replacing traditional electronic sensors due to their small size, resistance to electromagnetic interference, remote detection, multiplexing, and distributed measurement advantages. This makes them suitable for use in space applications and hazardous environments such as high-voltage machinery (e. Unlike traditional electrical temperature sensors (e. Fiber-Bragg-Gratings (FBGs) are used for spot sensing, whereas Rayleigh, Brillouin and Raman scattering are used for distributed sensing in long fibers.