Design and fabrication of sharp bend photonic crystal slab waveguides

Abstract

A periodic arrangement of atoms in a crystal presents a periodic potential for electrons. The bragg diffraction of electrons from the atoms may lead to a band gap, which represents a range of frequencies the electrons cannot have in the crystal. An analogous effect takes place in photonic crystals, which are periodic arrangement of layers of dielectric media. Scattering at the interface of the different layers produces a band gap for photons. The current effort to make integrated optical chips requires guiding light around sharp corners with a radius of curvature on the order of a wavelength. Photonic crystals serve this purpose by providing efficient sharp bend waveguides. An array of defects in a photonic crystal localizes modes in the band gap. This effect is used to build linear and 900 bend waveguides.