Fiber gratings can be classified into short-period fiber Bragg gratings (FBGs) and long-period fiber gratings (LPFGs) based on the size of the refractive index modulation period. FBGs typically have a grating period ranging from hundreds of nanometers to microns. This is achieved by creating a periodic variation in the refractive index of the fiber core, which generates a. With ongoing research and development, fiber Bragg gratings (FBGs) have evolved into a diverse and multifunctional field of study.