First cryogenic electro-optic switch on silicon with high bandwidth and low power tunability

We demonstrate the first electro-optic switch operating at cryogenic temperatures of 4 K with a high electrooptic bandwidth of > 18 GHz. Our novel technology exploits the Pockels effect in barium titanate thin films co-integrated with silicon photonics and offers low losses, pure phase modulation, and sub-pW electro-optic tuning.