Light Guiding in Low Index Materials using High-Index-Contrast Waveguides

We propose a novel high-index-contrast waveguide structure capable of light strong confinement and guiding in low-refractive-index materials. The principle of operation of this structure relies on the electric field (E-field) discontinuity at the interface between high-indexcontrast materials. We show that by using such a structure the E-field can be strongly confined in a 50-nm-wide low-index region with normalized average intensity of 20 μm. This intensity is approximately 20 times higher than that can be achieved in SiO2 with conventional rectangular or photonic crystal waveguides.