Understanding Defect Guidance in Kagome-Clad Structures

In this work we study structural features of interest in the kagome lattice in order to provide a better understanding of out-of-plane guidance of light within a defect in a kagome lattice cladding. With the aid of electromagnetic simulation we build and compare dispersion maps of select electromagnetic modes found within the hexagonal air-holes of the lattice and modes found in defects introduced into the lattice. Then, with the self-similarity of the lattice in mind, we arrive at a geometric explanation for the appearance of defect guided modes within the continuum of cladding states. Additionally, we study subsets of the kagome lattice related to band-gap structures to see their influence on dispersion and show that regions of guidance are influenced by band-gaps which appear for a subset of the kagome lattice. With these insights we provide design considerations to further decrease loss and widen regions of guidance in kagome-clad fibers