Er³⁺:Yb³⁺doped fibre with embedded FBG for simultaneous measurement of temperature and longitudinal strain

Abstract

A method for measuring temperature and strain simultaneously using a combination of the shift in a fibre Bragg grating and the fluorescence intensity ratio from Er3+:Yb3+ doped fibre is presented. This sensor scheme has the advantage of co-located measurement of temperature and strain as the Bragg grating is written into the Er3+:Yb3+ doped fibre. A number of these sensors were calibrated over temperature and strain ranges of 20–150 °C and 350–2530 με, respectively, and the measurement data analysed using various techniques. Temperature and strain values inferred from the sensors during these calibrations showed rms errors in the order of 0.3 °C and 4.9 & 0956;ε.