Effective index method for heterostructure-slab-waveguide-based two-dimensional photonic crystals

The validity of the two-dimensional approximation by the effective index method for heterostructure-slab-waveguide-based two-dimensional photonic crystals is tested against the full-vectorial three-dimensional finite-difference time-domain calculations. A good agreement over a wide frequency range is obtained for the band structures of two-dimensional photonic crystals in a low-index-contrast heterostructure. For high-index-contrast heterostructures, the effective index method is still valid, but only for much narrower frequency range. (C) 2002 American Institute of Physics.