Analysis of one-dimensional high-index guiding photonic bandgap waveguides

We present a detailed analysis of the guided modes of a one-dimensional photonic bandgap (PBG) waveguide that consists of a high-index guiding layer placed between two identical Bragg reflectors. Using a zigzag wave model, we calculate the modal characteristics of the waveguide including dispersion curves, field distributions, cutoff conditions, and confinement factors. We also investigate the effects of truncating the Bragg reflectors with either a high- or a low-index medium on the modal characteristics of the waveguide. The study provides a rigorous discussion of the two guiding mechanisms in the waveguide, namely index guiding and bandgap guiding. The results are useful not only for the design of PBG slab waveguides but also for a better understanding of the more complicated two-dimensional structures of the same nature, such as photonic crystal fibers and waveguides, which are not amenable to rigorous analytical studies. © 2009 Optical Society of America.