As quantum information technologies mature, it will become necessary to connect them by means of quantum networks. Unlike classical communications networks that transfer classical information, quantum networks must also transfer quantum states. As the only quantum particles capable of serving as flying qubits to carry quantum information across significant distances, photons will serve a foundational role in any future quantum network. Therefore, it is critically important to develop robust photon sources capable of generating photons with the characteristics needed for interfacing with networked quantum devices. We propose to address this need by developing a high-flux deterministic single-photon source using a nondeterministic photon-pair source. Like previous attempts, our approach will multiplex many probabilistic sources and use detection of one photon to herald the existence of the other. However, past attempts that have relied on a variable time or spatial mode memory have proven to be impractical due to an overdependence on strict requirements for low-noise, low-loss, high-speed switching technology to physically move the found photon into a desired mode. Here we propose a frequency-based method to demonstrate a deterministic single-photon source, where nonlinear optics is used to perform a fast, noiseless, photonic frequency shift into the desired output mode, and emission time jitter is limited by the classical pump pulse width. The proposed Phase I effort is envisioned to be the first part of a larger multi-phase project. The overall objective of all phases is to develop a deterministic high- flux single-photon source that not only meets the longer-term needs of quantum network applications but also leads to commercially viable products for the intervening period before quantum networks are widely deployed. The primary objective of the Phase I effort is to lay the groundwork for subsequent phases by advancing the technology from a notional concept to a detailed design suitable for prototype fabrication and testing. A high-flux source of single photons is expected to be an enabling technology that will have an immediate impact on multiple quantum technologies. The goal of this project is to advance the technology to the point that it becomes widely available to the quantum information community. This is likely to enable advances in a variety of quantum information applications, including quantum security, quantum computing, and quantum sensing. Quantum computing has been identified by DOE as an important technology for advanced scientific computing.
