The coefficient of thermal expansion (CTE) is used to determine the rate at which a material expands as a function of temperature. There are a variety of techniques to measure the CTE. Knowledge of this physical property is of fundamental importance in mechanical and structural design applications of a material.

As stated previously, fiber Bragg gratings are sensitive to temperature and strain. Therefore, it is possible to measure the CTE of a material using a Bragg grating bonded on it. The strain suffered by the material due to thermal expansion induces a proportional FBG deformation. This chapter describes how to measure the aluminum CTE.