Fiber Bragg Gratings (FBGs) are classified based on their refractive index modulation profile, periodicity, and spectral response. The primary types include uniform, chirped, tilted, and phase-shifted FBGs, each serving distinct applications in sensing, telecommunications, and. A fiber Bragg grating (FBG) is a type of distributed Bragg reflector constructed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all others. There are many types of fiber Bragg gratings. In this article, we will explore the definition, historical background, and importance of FBGs in modern optics. These gratings are inscribed on optical fibers using different methods, creating.