Schematic layout of long-distance entanglement distribution: Two separated quantum systems (here Rubidium atoms) become entangled in the emission process with a photon, respectively. Quantum frequency converters (QFC) are necessary to change the wavelength of the emitted photon (780 nm) to the telecom wavelengths. Two photon interference enables a Bell-state measurement (BSM) to swap the entanglement to the quantum systems.