Ge-rich silicon germanium as a new platform for optical interconnects on silicon

We propose germanium-rich silicon-germanium (SiGe) as a new platform for optical interconnects. The platform viability is experimentally and theoretically investigated through the realization of main building blocks of passive circuitry. Germanium-rich Si1-xGex guiding layer on a graded SiGe layer is used to experimentally show 12μm radius bends by light confinement tuning at a wavelength of 1550nm. As a next step, Mach Zehnder interferometer with 10 dB extinction ratio is demonstrated. High Ge content of the proposed platform allows the coupling with Ge-based active devices, relying on a high quality epitaxial growth. Hence, the integration on Silicon of high speed and low power consumption Ge-rich active components is possible, despite the high lattice mismatch between silicon and germanium.