title: Adiabatic mode coupling between SiGe photonic devices and SOI waveguides.
abstract: We describe the coupling between optical modes of silicon-on-insulator SOI waveguides and Ge/SiGe quantum well modulators using an eigenmode expansion method. Laterally tapered features in the epitaxial layers are investigated for adiabatic optical coupling, and we find that there is a critical width range of the Ge/SiGe structure of 200-300 nm, where the taper angle should be minimised. We identify optimised taper profiles, which, for 1-μm-wide waveguides, allow the length of an adiabatic taper to be reduced from 250 μm for a simple linear profile to 40 μm for the optimised structure.
authors: Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK. l.j.m.lever@leeds.ac.uk
authors: L
authors: L
authors: Lever
authors: Z
authors: Z
authors: Ikonić
authors: R W
authors: RW
authors: Kelsall