Highly efficient entanglement swapping and teleportation at telecom wavelength

Area of Science:

• Quantum Information Science
• Quantum Optics
• Quantum Networking

Background:

• Entanglement swapping is crucial for quantum networks but limited by low operational rates.
• Existing methods struggle with efficiency in entangled photon sources and detectors at telecom wavelengths.

Purpose of the Study:

• To significantly enhance the efficiency and rate of entanglement swapping at telecom wavelengths.
• To enable practical quantum communication protocols and quantum key distribution.

Main Methods:

• Utilized two ultra-bright entangled photon sources.
• Employed four highly efficient superconducting nanowire single-photon detectors.
• Achieved high coincidence count rates and Hong-Ou-Mandel interference visibility.

Main Results:

• Attained a four-fold coincidence count rate of 108 counts per second, three orders higher than previous experiments.
• Demonstrated a raw visibility of 73.3% and net visibility of 85.1% in Hong-Ou-Mandel interference.
• Achieved a fidelity of 76.3% in entanglement swapping tests.

Conclusions:

• The developed setup drastically improves entanglement swapping efficiency at telecom wavelengths.
• Results pave the way for practical device-independent quantum key distribution and multi-photon entanglement generation.
• Enables quantum networking over fiber and space links using telecom band infrastructure.