Shehab A. Kadhim, Salah Aldeen A. Taha, Dehyaa A. Resen
Optical fiber plays significant roles in optical communications, optoelectronics, and sensors. The FBG sensors exceed other conventional electric sensors in many aspects, for instance, immunity to electromagnetic interference, light weight, compact size, stability, flexibility, high temperature tolerance, and resistant to harsh environment. This paper provides the operating principle, implementation of a “strain-free” FBG temperature sensors head and spectral characterization study. High-resolution detection of the wavelength-shifts induced by temperature changes are achieved using optical spectrum analyzer. Both uniform Fiber Bragg Grating (FBG) temperature and Mach-Zehnder Interferometric (MZI) temperature sensors based on single mode fibers were implemented and investigated due to measurement of the Bragg wavelength shift. It has been shown from the results that the FBG is very sensitive to variations in temperature degrees over a temperature range of (5–70) oC and the sensitivity was (1-6 pm/0.1°C), also observed from the results, the relation between the shifted Bragg wavelength and temperature degrees was linear.