Fiber optic sensing works by measuring changes in the “backscattering” of light occurring in an optical fiber when the fiber encounters vibration, strain or temperature change. From energy. Rationale for optical temperature sensing and WBGs Most current temperature sensors rely on a thermistor, which is a resistor whose resistance changes with temperature (an example is given in Typical thermistor (a)). Put simply, when a constant voltage is applied over the thermistor, changes in the. Fiber optic sensing technology in engineering has grown significantly and marks substantial progress in the measuring and monitoring domains. Due to the wavelength dependence on temperature and strain, FBGs are widely used for optical sensing.