Nanofabrication of high refractive index contrast two-dimensional photonic crystal waveguides

We present the fabrication of high refractive index contrast two-dimensional photonic crystal (2D-PC) slab waveguides. 2D photonic crystal structures, consisting of a periodic array of holes in a GaAs matrix, are obtained by nanopatterning of epitaxially grown GaAs/AlGaAs heterostructures. Two different PC structures will be described in detail: (i) an asymmetric 2D-PC slab waveguide obtained by selective oxidation which transforms the Al-rich AlGaAs cladding layer underneath the PCs into aluminium oxide and (ii) a symmetric 2D-PC slab waveguide obtained by removing the oxide (free standing structure).