Total Internal Light Confinement

Abstract

PHYSICS In traditional light-guiding techniques, the light is confined to the region of high refractive index by total internal reflection. However, miniscule modulations or defects on the surface can lead to significant diffractive losses of the light out of the guide and are generally difficult to remove. Chutinan et al. propose a scheme involving the coupling of two- and three-dimensional (3D) photonic bandgap structures to suppress these diffractive losses. In their proposed design and fabrication scheme, the optical network is patterned in a 2D layer of a photonic crystal slab. This is then sandwiched between 3D photonic bandgap cladding layers, which are specifically engineered to prevent any leaky modes at the wavelength of interest. Although experimental verification is some way off, the simulated results of all-optical networks indicate a promising route toward leak-free all-optical microchips.— ISO Phys. Rev. Lett. 90 , 123901 (2003).