The paper presents the results obtained in simulation of fiber Bragg grating (FBG) and long-period grating (LPG) sensors and their applications. Fiber Bragg grating (FBG) sensors have emerged as advanced tools for monitoring a wide range of physical parameters in various fields, including structural health, aerospace, biochemical, and environmental applications. Coupled-mode theory and the. Simulations on the FBG are carried out using Origin Pro 2016 and Microsoft Excel 2010 software. a few millimeters or centimeters, and the period is of the order of.