Photon qubit basis encoding for heterogeneous quantum networking*

Quantum networks are useful for scaling quantum information systems, including processors, sensors, and communications. Depending on the environment in which a quantum network operates, including distance, noise, environmental perturbations, ease of measurement, and other parameters, as well as the composition of the network's nodes, some photonic qubit encoding types are more advantageous than others. Here, we explore photon basis interconversion modules that convert between time-bin and polarization encoding of photons in the telecom C-band. While the photons are encoded in the time basis, we observe polarization drifts in the optical fiber which change the rate of qubit transmission but not the fidelity. Our results show that these prototypes can be used within high-fidelity quantum networking protocols to connect different matter-based quantum systems, such as trapped ion qubits and superconducting qubits. This functionality is a building-block toward heterogeneous quantum networks, in that it can bridge between different photon encoding schemes that are most natural to different quantum systems.