Bell State Measurement between Two Spectrally Multiplexed Elementary Quantum Links

We demonstrate a Bell state measurement (BSM) between two spectrally multiplexed elementary quantum links by using two time-bin photonics qubit generators with different spectral channels. A projection fidelity of >95% is achieved by erasing the spectral distinguishability between adjacent nodes of the two links with single-photon frequency shifting while the separation between spectral channels is carefully designed according to parameters of time-bin qubits.