Ultrahigh-Q on-chip silicon-germanium microresonators for quantum transduction
Abstract
As an entirely monocrystalline photonics platform, $Si_1-xGe_x/Si$ is a promising has exceptionally low losses in both microwave [1] optical [2] and domains, with internal optical quality factors reaching 170M at room temperature. At 4 K, $Si_1-xGe_x/Si$ waveguides still have high quality factors but also a low threshold for bistability and pulsation, which are nonlinear optical effects deriving from the interplay between optically generated free carrier dispersion and thermo-optics. While instabilities deriving from them can be detrimental, they can be mitigated by applying DC electric fields. Together with silicon’s intrinsically high (3) tensor, this active control over nonlinearities could lead silicon germanium to applications like electro-optic modulation [3], optical logic, Kerr comb generation, and quantum transduction [4]. This work was funded by Laboratory of Physical Sciences CQTS program through an Army Research Office grant W911NF-18-1-0022. [1] Schilling et al, Optica 9, 284 (2022) [2] Sandberg et al, Appl. Phys. Lett. 118, 124001 (2021) [3] Timurdogan et al., Nature Photonics 11, 200 (2017). [4] Orcutt et al, Quant. Sci. Tech. 5, 034006 (2020)