Reactive ion etching: a versatile fabrication technique for micro-optical elements

Abstract

Reactive ion etching (RIE), a well established technology in semiconductor industries, has proven to be also a versatile tool for the fabrication of optical components. Using fluor based processes, we fabricated refractive spherical and cylindrical microlenses as well as various diffractive optical elements (DOEs) e.g. Fresnel zone lenses (FZLs), linear binary gratings, triangular gratings etc., in quartz glass and in silicon. Furthermore we realized waveguide components, above all arrayed waveguide gratings (AWGs) in silica on silicon for WDM applications. To meet the specific demands of these various optical structures (differing in shape, feature size, resolution, etch depth, etc.) appropriate structuring methods, mask materials and etching parameters had to be chosen.