Fabrication of high-temperature temperature sensor based on dielectric multilayer film on Sapphire fiber tip

• Multilayers construction was used to optimize the reflected spectrum.
• The sensor was fabricated on the tip of a polished sapphire fiber in batch volume by EB-PVD process.
• The sensor shows a very high correlation with environment temperature at 100.9–1111.0 °C
• Multilayers dielectric film has a good high-temperature resistance.

A high-temperature temperature sensor based on dielectric ZrO2 / Al2O3 / ZrO2 (ZAZ) three-layer film structure on sapphire fiber tip with potential for low-cost batch production was fabricated. A fiber optic high-temperature sensor based on the principle of Fabry-Perot structure is proposed. The ZAZ three-layer film sensing element was deposited on the tip of a polished sapphire fiber using physical vapor deposition (PVD). Due to exceptionally small size, the as-prepared temperature sensor based on sapphire fiber tip can be used as an embedded sensor in harsh environments. And experimental result shows that the sensor based on sapphire fiber has a very high correlation with environment temperature; the correlation coefficient was measured to be 99.79%. The sensitivity of temperature reaches 1.8 × 10−5 /°C when the environment temperature changes from 100.9 °C to 1111.0 °C.