Fiber optic temperature sensors operate based on changes in light properties as it travels through the fiber. Suitable for long-range distributed temperature. This article explores the structure, working principles, advantages, and disadvantages of Fiber Optic Temperature Sensors. TEMPERATURE SENSOR Principle: It is based on the principle of interference between the beams emerging out from the reference fiber and the fiber kept. A fiber optic sensor generally guides light to and from a measurement zone where the light is modulated by the measurand of interest and returned along the same or a different optical fiber to a detector at which the optical signal is interpreted.