Spectral characteristics of a photonic bandgap fiber

With the help of numerical simulation, we study the propagation of light in an all-glass photonic crystal fiber. A comparison of the spectral characteristics of a fiber with the idealized hexagonal structure and a fiber with transverse profile deformations is conducted. The calculations use methods based on a spatial Fourier transform. It is shown that total internal reflection modes and the fundamental mode of the photonic bandgap can be excited simultaneously. Structural deformation of a photonic crystal fiber results in the shifting and narrowing of the photonic bandgap. Excitation of the total internal reflection modes leads to increased absorption on the boundaries of the spectral band of the fiber.