Reflection Spectrum Characteristics of Bragg Fiber Bragg Grating

Based on the coupled mode theory of fiber Bragg grating, OptiGrating software was used to simulate the main factors affecting the reflection spectrum of fiber Bragg grating (FBG) and cascaded FBG, and the response characteristics of the reflection spectrum were obtained. The simulation results show that when the length of the grating increases, the center wavelength of the peak stays the same and the reflectance increases. When the grating period increases, the wavelength of the center of the peak shifts to the direction of the long wave, and the reflectance is basically unchanged. When the modulation of refractive index of grating increases, the center wavelength of wave peak remains unchanged and the reflectance increases. When the period difference of the cascaded gratings is large, the reflection spectrum of the cascaded FBG is the superposition of the reflection spectrum of the individual gratings. When the period difference of the gratings is close, there will be interference between the gratings.