Accurate Temperature Compensation and Characterization of Overall System Thermal Response Using Total Measured Strain in FBG Sensors

Abstract

One of the most common fiber optic sensor (FOS) types used are fiber Bragg gratings (FBG) -based strain sensors are simultaneously sensitive to both temperature and strain. Thus it is essential to utilize sensors that are either fully temperature insensitive or, alternatively, properly temperature compensated to avoid erroneous measurements. In this paper, we introduce the concept of measured “total strainâ€, which is inherent and unique to optical strain sensors. We review and analyze the temperature and strain sensitivities of FBG strain sensors and decompose the total measured strain into thermal and non-thermal components. We explore the differences between substrate CTE and System Thermal Response Coefficients, which govern the type and quality of thermal strain decomposition analysis.