Figure 4: Photonic crystals drive light round the bend
(a) A photonic-crystal waveguide splitter. The grey rectangular area is
composed of millions of air holes that form a photonic crystal. The Y-shaped
region is the so-called defect waveguide that is formed by removing rows of
holes from the lattice. The thick parallel lines are isolated waveguides that
transmit light to and from the photonic-crystal splitter device (b) A
close-up view of the defect waveguide shows the lattice structure in detail.
(c) Light enters the device from the bottom and is split into two beams
that are perpendicular to the incoming beam.