Experimental demonstration of evanescent coupling and photon confinement in oxide-clad silicon microcavities

For use in on-chip and integrated applications, photonic crystals must not only be embedded in silica but must also be able to easily integrate with other photonic devices. Here we provide an experimental demonstration of resonance in a SiO(2)-clad two-dimensional photonic crystal microcavity that is coupled to standard Si strip waveguides. We further show that well over 90% of the resonant field is confined within the cavity's silicon layer, which is necessary if the microcavity is to be used as a high-efficiency electro-optic modulator.