Three-dimensional photon confinement in photonic crystals of low-dimensional periodicity

Photonic crystals of one- or two-dimensional periodicity can be used to ach ieve three-dimensional photon confinement in dielectric waveguides with mod al volumes of the order of a cubic half-wavelength. Since photonic crystals of low-dimensional periodicity do not have full three-dimensional bandgaps , the microcavities undergo increasing radiation losses with decreasing mod al volumes. High-Q resonant modes can be generated by reducing the strength of the photon confinement. Increasingly, larger modal volumes lead to lowe r radiation losses and more efficient coupling to waveguide modes outside t he cavity.