PHASE-II: Robust all-optical room-temperature quantum buffers for photonic quantum technologies

Quantum technologies are the next frontier. Qunnect has developed a prototype Quantum Buffer device that provides networks the capability to store, coherently manipulate, and temporally synchronize quantum-states. Their technology is one of the critical enablers of quantum repeaters, which will form the basis of large-scale quantum networks, and eventually, the Quantum Internet. The first stages of these networks will enable unbreakable privacy and security in communications. More developed networks will permit a range of applications for spectacular entanglement-based technologies which cannot be achieved with classical systems alone, enabling novel applications including quantum teleportation of large amounts of data and distributed quantum computing. US DOE support has enabled a feasibility study on these quantum buffers, engineered to be placed into existing fiber beds with minimal infrastructural support, and enabling buffered quantum communications. The SBIR phase II will support the design of a commercial MVP with improved performance specifications for field deployment and telecom integration, including plug-&-play features and remote-controlled monitoring. These devices will bring the US a step closer to the realization of nationwide quantum networks. Qunnect is developing a modular room-temperature Quantum Buffer (QB) device, an integral component within full-scale distributed quantum networks, permitting efficient synchronization of qubits across the network. To achieve high fidelity storage, the QB uses a light-matter coupling to provide an interface that allows for temporary mapping of the photonic qubits on a collective atomic state. This collective atomic excitation can be retrieved as a photonic qubit, indistinguishable from the input qubit, but with a time delay programmed to synchronize the network. Our design goals include compatibility and easily integration into existing fiber-based photonic networks to utilize existing telecom infrastructure in our long-term vision of realizing a nationwide quantum-secure network. In Phase I, we completed a prototype of a rack-mounted, room-temperature QB with superior performance specifications to the original laboratory implementation. We demonstrated the prototype’s portability and performance by deploying the device outside of a laboratory and storing photon packets (classical storage) sent from a distant laboratory with storage times of up to 400μs. Our Phase II goals include the buildout of improved performance features and remote monitoring/control of the QB devices. These features are of great interest to our first customers and will enable the device’s commercialization. To our knowledge, we are the first company pursuing commercialization of room temperature deployable rackmount QBs. Qunnect sees this as an exceptional opportunity to fill a market need and to become a standard component for the field. At present, commercial demonstrations of fiber-based quantum communications have been distance-limited due to the technical barriers to producing quantum-compatible hardware, analogous to the existing optical telecom device suite. To realize their true commercial potential, quantum devices need to be designed to operate in the existing telecom fiber beds with minimal support infrastructure, field stability, and remote monitoring/control. Qunnect is developing a field-deployable Quantum Buffer device that provides the network the capability to store, coherently manipulate, temporally synchronize, and retrieve quantum-states on-demand. The buffer is an essential component to other devices, most importantly, a quantum repeater, which will eliminate distance limitations, enabling the buildout of nationwide quantum networks. In Phase I, Qunnect completed a prototype of a rack-mounted, quantum buffer that operates at room temperature, with performance specifications that exceeded our original table-top design. We demonstrated the prototype’s field-compatibility storing photon packets sent from a distant laboratory to the device’s location (outside of the laboratory). Using efficiency-optimization protocols, these devices have obtained an operating qubit fidelity of close to 90% and have been confirmed at classical levels to achieve up to 400μs lifetimes with >50% storage efficiency. Based on the outcome of the prototype, we drafted the design of the next generation. The objectives of Phase II are to transition the existing prototype into a Minimal Viable Product. The performance milestones can be split into two categories: 1) quantum performance features: higher fidelity (ultra-low-noise regimes), improved storage efficiency, and telecom wavelength operation; and 2) mechanical/electro-optical engineering features: devices must be modular, stable, cost-effective, and remotely monitored/controlled. Quantum networks and the Quantum Internet, exploiting the unique effects of quantum mechanics, would be fundamentally different from the classical Internet we use today; research groups and industries worldwide are working on its development. The first stages promise virtually unbreakable privacy and security in communications. More mature networks will include a range of applications for big-science, and spectacular entanglement-based technologies which cannot be achieved with classical systems alone, enabling novel applications including quantum teleportation of large amounts of data, distributed quantum computing, large-scale quantum communication, cooperative synchronization of atomic clocks, and even sensing beyond the shot-noise frontier.