Measurements of sidewall roughness by atomic force microscopy has been used to understand the waveguides losses of Ge-on-Si mid-infrared rib waveguides. Simulations indicate the measured roughness is well below values corresponding to the measured losses indicating sidewall roughness scattering is not the dominant loss mechanism.
Ugne Griskeviciute, Kevin Gallacher, Ross W. Millar, Douglas J. Paul and Iain MacGilp