Fiber Bragg Grating Based Thermometry

TL;DR

This paper investigates the thermal response of Fiber Bragg Gratings (FBG) sensors over a broad temperature range, highlighting their quadratic temperature dependence and the main sources of measurement uncertainty.

Contribution

It provides a detailed analysis of FBG thermometry performance and identifies key factors affecting measurement accuracy in a sealed Argon environment.

Findings

FBG shows quadratic temperature dependence from 233 K to 393 K

Measurement uncertainty is around 500 mK (k=2)

Uncertainty sources include peak fitting and fiber aging

Abstract

In recent years there has been considerable interest in developing photonic temperature sensors such as the Fiber Bragg gratings (FBG) as an alternative to resistance thermometry. In this study we examine the thermal response of FBGs over the temperature range of 233 K to 393 K. We demonstrate, in a hermetically sealed dry Argon environment, that FBG devices show a quadratic dependence on temperature with expanded uncertainties (k = 2) of ~500 mK. Our measurements indicate that the combined measurement uncertainty is dominated by uncertainty in determining the peak center fitting and by thermal aging of polyimide coated fibers.