Fabrication of silicon 3D taper structures for optical fibre to chip interface

Abstract

In order to exploit the full potential of silicon photonic devices we require an efficient way of coupling light from fibers to integrated photonic circuits. One of the most common solutions to this problem is the use of tapered silicon waveguides. We present a method of vertical silicon taper fabrication using KOH anisotropic etching of a silicon wafer with tilted 〈1 1 1〉 crystallographic orientation. The main advantage of this method is good reproducibility and the low roughness of the tilted surface, which should lead to a good optical transmission of the tapered waveguide.