This paper reviews the sensing principle, structural design, and temperature measurement performance of fiber-optic high-temperature sensors, as well as recent significant progress in the transition of sensing solutions from glass to crystal fiber. High-temperature measurements above 1000 °C are critical in harsh environments such as aerospace, metallurgy, fossil fuel, and power production. Fiber-optic high-temperature sensors are gradually replacing traditional electronic sensors due to their small size, resistance to electromagnetic. Optical fiber sensors have the advantages of small size, easy design, corrosion resistance, anti-electromagnetic interfer-ence, and the ability to achieve distributed or quasi-distributed sensing and have broad application prospects for temper-ature sensing in extreme environments. Up to now, MEISU has developed various high-temperature resistant optical devices not only with regular SM fiber, but also. These features enable this new optical fiber to be used for high density cabling and optical fiber sensing in high-temperature environments up to 200 ̊C. Standard commercial adhesives typically only survive up to about 400 C. But, they detach at >500 C at the higher operating.
