Novel, low-index waveguide as laser external cavity

Here we present a novel waveguide providing > 70% optical power confinement in a relatively small area, 0.12μm2, which could be used to fabricate quantum dot or other sub-wavelength-sized active regions, modulators or detectors on Si. This structure forms a novel, low-index waveguide which can be engineered to have properties similar to high-index or slot waveguides, showing that there is in fact a continuum between these two waveguides.