The Governing Council of the University of Toronto

Purpose

Entanglement distribution is a key function required by a quantum network. For longdistance networks, quantum information is typically carried by the polarization of photons and transmitted over optical fibres. Polarization entanglement, while convenient to produce and detect, degrades over long distances in optical fibres. The project will explore a new entanglement distillation method, using polarization-frequency hyperentanglement, for improving the quality of the entangled photons after distribution. The proposed method efficiently “distills” the polarization entanglement by performing a control-not (CNOT) operation between the polarization qubit and the frequency qubit, using a sum-frequency generation scheme. This new scheme eliminates a major noise source, allows for more efficient entanglement distillation, and is more robust. The method requires pulsed lasers emitting at multiple stable frequencies to perform the necessary frequency conversions. Working together the team will develop a novel entanglement distillation technology based on the NRC-home-made quantum-dot coherent comb lasers.