Efficient preparation of large, but definite, numbers of photons is of great importance for scaling up and speeding up photonic quantum information processing. Typical single-photon generation techniques based on nonlinear parametric processes face challenges of probabilistic generation. Here we demonstrate efficient synchronization of photons from multiple nonlinear parametric heralded single-photon sources, using quantum memories. Our low-loss optical memories greatly enhance (∼30×) the generation rate of coincidence photons from two independent sources, while maintaining high indistinguishability (95.7±1.4%) of the synchronized photons. As an application, we perform the first demonstration of parametric-source-based measurement-device-independent quantum key distribution. The synchronization technique demonstrated here paves the way toward efficient quantum communication and larger-scale optical quantum computing.
- Photon statistics
- Quantum communications
- Quantum information and processing
- Quantum optics