The most sensitive method for detecting gratings is in reflection, and for this reason it is best to measure gratings in reflection for diagnostic purposes and display the signal on an optical spectrum analyzer. The bandwidth, reflection profile, and phase response of gratings require special measurement techniques for proper characterization. But just how does a fiber Bragg grating work? Our experts answer this and other questions. This paper gives a short introduction to FBG sensors, points out their special strengths and weaknesses and describes a measuring system which enables strain gages and FBGS to be measured simultaneously, providing all data processing functions originally developed for the strain gages also for the. Fiber Bragg grating has embraced the area of fiber optics since the early days of its discovery, and most fiber optic sensor systems today make use of fiber Bragg grating technology. This technology relies on periodic structures within optical fibers that modify the propagation of light, enabling a myriad of applications ranging from telecommunications to environmental.