Mid-IR Optical and Nonlinear Properties of Germanium on Silicon Optical Waveguides

The influence of Germanium-on-Silicon waveguide geometries on single-mode and multimode operations as well as on zero birefringence conditions has been deeply investigated in the mid infrared spectrum. The design equations to estimate the single mode conditions have been carried out and interpolated by exponential functions. Moreover, the group velocity dispersion and third-order dispersion have been investigated in the range 3–6 μm as a function of various waveguide geometries. Finally, nonlinear properties, for instance the modal Raman gain, have been investigated, comparing with Silicon-on-Insulator waveguides. The set of results identifies accurate guidelines for the design of these optical waveguides for several applications.