Photonic crystal waveguides in PECVD glass

Silicon oxynitride (SiON) on silicon has found wide use as a robust and versatileplatform for integrated, optical devices. With plasma-enhanced chemical vapourdeposition (PECVD) the refractive index can be varied all the way from 1.5 (pure silica,SiO2) to 2.0 (pure silicon nitride, Si3N4). We have fabricated glasses with refractive indexup to approximately 1.75, with which value it is possible to fabricate photonic crystalwaveguides.

These structures have the advantage of being transparent in the whole of thevisible region, which makes them different from photonic crystals made in semiconductormaterials, and attractive in, e.g., biological applications. For operation in the visibleregion, the photonic crystal waveguide must be realized with a 2D lattice of air holes thatare spaced with a period of ~ 300 nm.

In this poster, we report on simulations of theoptical guiding in these structures and preliminary fabrication with the use of e-beamwriting and reactive-ion etching.