Temperature measurement using a fused optical fiber coupler in arc environment

We demonstrate a novel high temperature measurement system in the range of 1700°K to 2500°K using fused optical fiber couplers. The refractive index variation with the change of glass structure depending on the temperature profile parameters is utilized to measure the temperature around the arc, where the opto-thermometric property, e.g., change of refractive index of optical material due to heat, resulting in change of amount of coupled power of a fused 2 × 2 optical fiber coupler due to addition of heat through arc discharge at the coupler waist is used. The variation of coupled power with the change of temperature for different values of effective coupling length is shown and the theoretical curves are compared with the experimental results.