Numerical Study on Bragg Fibers for Infrared Applications

The photonic band structure, waveguiding mechanism, mode field distribution, leakage loss, and material loss of Bragg fiber are studied by the full vectorial plane wave expansion method and the transfer matrix method. Systematical study has shown the distinctive properties of Bragg fiber and the similarity between Bragg fiber and hollow metallic waveguide, demonstrating the feasibility of Bragg fiber to work in a low loss, single mode manner. Furthermore, a comparison between the band structures calculated by plane wave expansion method and by transfer matrix method is conducted to show the practicability to treat Bragg fibers electromagnetic behavior in a Bloch theorem approach, verifying the photonic bandgap concept for the analysis of Bragg fiber.