Photonic Integrated Circuits and Components for Quantum Key Distribution.

In this talk, we present designs of photonic integrated circuits and components for applications in quantum communications. The goal is to miniaturize the instrumentation while optimizing the security of various quantum key distribution protocols, such as BB84 with different qubit encodings, and measurement-device-independent protocols (MDI-QKD). The proposed components include diffraction gratings for polarization coupling, on-chip path-polarization interconverters, nanoantennas, and graphene nanocavities for coupling individual photon emitters. We simulate the behavior of the proposed circuits and components, and analyze the quantum key error for different parameters, comparing the advantages of single photons and weak coherent states.