Patent ID: 7072553

Claim:
An all-dielectric waveguide comprising: a dielectric core region extending along a waveguide axis; and a dielectric confinement region surrounding the core about the waveguide axis, the confinement region comprising alternating layers of at least two different dielectric materials surrounding the core about the waveguide axis, wherein during operation the confinement region guides EM radiation in at least a first range of frequencies to propagate along the waveguide axis in the core, wherein the core has an average refractive index smaller than about 1.3 for a frequency in the first range of frequencies, wherein the core has a diameter in a range between about 4λ and 80λ, wherein λ is a wavelength corresponding to a central frequency in the first frequency range, and wherein the refractive indices and thicknesses of at least some of the alternating dielectric layers substantially satisfy the following equality: d hi d lo = n lo 2 - 1 n hi 2 - 1 where d hi and d lo are the thicknesses of adjacent higher-index and lower-index layers, respectively, and n hi and n lo are the refractive indices of the adjacent higher-index and lower-index layers, respectively.