Sensing Principle Analysis of FBG Based Sensors

Abstract

In this paper the temperature and strain sensing principle of FBG based sensors are analyzed through experimental procedures. The property of the FBG changes due to the thermo-optic and elasto-optic effect which results the change of period of the gratings & the effective refractive index respectively. Due to this FBG's property change results Bragg wavelength shift. From the measured Bragg wavelength shift with respect to the reference (at room temperature & no strain applied) Bragg wavelength we can calculate the corresponding temperature or strain. For this type of temperature sensor the sensitivity found is C pm/) 13. 0 9. 9 ( .