This example demonstrates a temperature sensor based on fiber Bragg gratings (FBG). The temperature-dependent change of the refractive indices of the fiber, consequently the shift of its Bragg wavelength, is used as a measure of the temperature. Optical fiber Bragg grating (FBG) to be considered in. It is a single point contact temperature measurement system. A Fluorescent sensor is formed at the tip of the Optical Fiber. The light source is used to excite the Fluorescent material. They are formed by a periodic modulations of the. Fiber optic temperature sensors are immune to the many environmental effects that compromise other measurement technologies, can be embedded and installed in locations traditional temperature sensors cannot and deliver an unprecedented level of spatial detail and data without sacrificing precision. A high-temperature sensor based on a regenerated fiber Bragg grating is developed, and a thermal study of the sensor up to a temperature of 1000°C is performed. The regenerated fiber Bragg grating was produced by annealing a “seed” fiber Bragg grating recorded on SMF-28 hydrogen-loaded.