An Active Core Fiber-Optic Temperature Sensor Using an Eu(III)-Doped Sol-Gel Silica Fiber as a Temperature Indicator

An active core fiber-optic temperature sensor has been developed by using an Eu(III)-doped sol-gel silica fiber as a temperature indicator and has been tested for sensing temperature in the range from 80 degC to 500 degC. The fluorescence of Eu(III) doped inside the sol-gel silica fiber was excited with a simple LED with peak wavelength at 420 nm and the fluorescence intensity was recorded as a sensing signal. The fluorescence intensity decreases with the increase of temperature. In the temperature range from 140 degC to 300 degC, the attenuation of the fluorescence intensity of the fiber-optic sensor in decibel has a linear relationship with temperature