We report on the realization and verification of quantum entanglement between a nitrogen-vacancy electron spin qubit and a telecom-band photonic qubit. First we generate entanglement between the spin qubit and a 637 nm photonic time-bin qubit, followed by photonic quantum frequency conversion that transfers the entanglement to a 1588 nm photon. We characterize the resulting state by correlation measurements in different bases and find a lower bound to the Bell state fidelity of ≥0.77±0.03. This result presents an important step towards extending quantum networks via optical fiber infrastructure.
Supporting data for Entanglement between a Diamond Spin Qubit and a Photonic Time-Bin Qubit at Telecom Wavelength
Tchebotareva, A. (Creator), Hermans, S. L. N. (Creator), Hanson, R. (Creator), Cheng, L. K. (Contributor), De Jong, W. (Contributor), Dijkhuizen, N. (Contributor), Dréau, A. (Contributor), Harmsma, P. (Contributor), Humphreys, P. (Contributor), Verlaan, A. L. (Contributor) & Voigt, D. (Contributor), TU Delft - 4TU.Centre for Research Data, 2020