Cryogenic Operation of Silicon Photonic Electro-Optic Modulators based on DC Kerr Effect*

Scalable photonic integrated circuits operating at cryogenic temperatures are essential for quantum information processing and supercomputing. The silicon-on-insulator platform is highly promising for its compactness and CMOS compatibility. However, efficient electro-optic modulation in silicon at cryogenic temperatures remains an outstanding challenge, owing to carrier freeze-out at cryogenic temperatures in conventional plasma-dispersion-based modulators [1]. The generation of an induced second-order nonlinearity in silicon with an applied DC electric field has been demonstrated at room temperature [2]. In this work, we demonstrate DC Kerr-based modulation in silicon at a temperature of 5K at GHz speeds, showing the potential of DC Kerr modulators for use in large-scale silicon photonic integrated circuits for cryogenic computing.

[1] Gehl, M., et al. Optica 4.3, 374-382 (2017)
[2] Timurdogan, E., et al. Nature Photonics 11.3, 200 (2017)