Quantum teleportation over 100 km of fiber using highly efficient superconducting nanowire single-photon detectors

Quantum teleportation is an essential quantum operation by which we can transfer an unknown quantum state to a remote location with the help of quantum entanglement and classical communication. Since the first experimental demonstrations using photonic qubits and continuous variables, the distance of photonic quantum teleportation over free-space channels has continued to increase and has reached > 100 km. On the other hand, quantum teleportation over optical fiber has been challenging, mainly because the multifold photon detection that inevitably accompanies quantum teleportation experiments has been very inefficient due to the relatively low detection efficiencies of typical telecom-band single-photon detectors. Here, we report on quantum teleportation over optical fiber using four high-detection-efficiency superconducting nanowire single-photon detectors (SNSPDs). These SNSPDs make it possible to perform highly efficient multifold photon measurements, allowing us to confirm that the quantum states of input photons were successfully teleported over 100 km of fiber with an average fidelity of 83.7 +/- 2.0%. (C) 2015 Optical Society of America