Simultaneous measurement of strain and temperature using type I and type IIA fibre Bragg gratings

Abstract

We present a fibre optic sensing head for making simultaneous measurements of temperature and strain, which operates over a large temperature range. The configuration is based on the different temperature sensitivities of type I and type IIA gratings written in a fibre with high germanium content. Maximal errors of ± 0.7°C Hz−1/2 and ±3.8 µe Hz−1/2 are reported over 500°C and 1200 µe measurement ranges, respectively.