A waveguide structure formed with a three-dimensional (3D) photonic crystal is
disclosed. The 3D photonic crystal comprises a periodic array of voids formed in
a solid substrate. The voids are arranged to create a complete photonic bandgap.
The voids may be formed using a technique called "surface transformation," which
involves forming holes in the substrate surface, and annealing the substrate to
initiate migration of the substrate near the surface to form voids in the substrate.
A channel capable of transmitting radiation corresponding to the complete bandgap
is formed in the 3D photonic crystal, thus forming the waveguide. The waveguide
may be formed by interfacing two 3D photonic crystal regions, with at least one
of the regions having a channel formed therein. The bandgap wavelength can be chosen
by arranging the periodic array of voids to have a lattice constant a fraction
of the bandgap wavelength.
