This article explains the principle of Fiber Bragg Grating (FBG) sensors based on the fundamental concept of "reflection and interference of light waves," including the principles of temperature measurement, stress measurement, and strain measurement using FBGs. This review provides a comprehensive overview of FBG sensor technology. In this Chapter we will concentrate on a very special type of OFS: the Fiber Bragg Grating (FBG) sensors. Werneck, Regina Célia da Silva Barros Allil, and Fábio Vieira Batista de Nazaré 10 November 2017 Publications The development of optical fibers has revolutionized not only. A good solution for this problem is the measurement of parameters by optical fiber based FBG sensor.