A Method to Discriminate Strain and Temperature in Fiber Bragg Grating Sensors

A significant limitation to the applications of fiber Bragg gratings (FBG) sensors is the sensitivity of the Bragg wavelength to both temperature and strain, complicating the independent measurement of these parameters. In this letter, we explore a new method to discriminate strain and temperature in FBG sensors, which utilizes the additional wavelength dependent phase introduced by Fiber Bragg grating written on sensing arm of Mach Zehnder interferometer (MZI). The intensity variations of the MZI output at the wavelength outside the Bragg resonance provide an additional parameter along with the Bragg wavelength shift observed at the input end for simultaneous measurement of strain and temperature