Metropolitan-Scale Quantum Link: A Leap Forward in Quantum Internet Technology

The Metropolitan-Scale Quantum Link, a significant development in quantum internet technology, connects quantum processors at a metropolitan scale. Developed by a collaboration of institutions, the Quantum Link involves two independently operated quantum network nodes separated by 10km, linked via 25km of optical fiber. The system mitigates photon loss and enables the delivery of a predefined entangled state on the nodes. The Quantum Link’s extensible architecture, precise polarization and timing control, and active stabilization of the relative optical phase between photons emitted from the nodes contribute to its potential for efficient entanglement generation, making it a key tool for the development of large-scale quantum networks.

What is the Metropolitan-Scale Quantum Link?

The Metropolitan-Scale Quantum Link is a significant development in the field of quantum internet technology. It involves the connection of quantum processors at a metropolitan scale. This development is the result of a collaboration between several institutions including QuTech, Kavli Institute of Nanoscience, Delft University of Technology, Netherlands Organisation for Applied Scientific Research, Element Six Innovation, Fraunhofer Institute for Laser Technology, Chair for Laser Technology, RWTH Aachen University, and TOPTICA Photonics AG.

The Quantum Link involves two independently operated quantum network nodes separated by 10km. These nodes, which host diamond spin qubits, are linked with a midpoint station via 25km of deployed optical fiber. The effects of fiber photon loss are minimized by quantum frequency conversion of the qubit-native photons to the telecom L-band and by embedding the link in an extensible phase-stabilized architecture. This enables the use of the loss-resilient single-photon entangling protocol.

The Quantum Link capitalizes on the full heralding capabilities of the network link in combination with real-time feedback logic on the long-lived qubits. This allows for the delivery of a predefined entangled state on the nodes, irrespective of the heralding detection pattern. This architecture addresses key scaling challenges and is compatible with different qubit systems, making it a generic platform for exploring metropolitan-scale quantum networks.

How Does the Quantum Link Address the Challenges of Quantum Networking?

The Quantum Link addresses several challenges associated with quantum networking. One of the major challenges in the development of quantum network systems is the ability to generate, store, and process quantum information on metropolitan scales. Such systems face several new requirements due to the large physical distance, consequential significant communication times, and need for scalability.

The Quantum Link addresses these challenges by enabling the network nodes to operate fully independently. This is crucial as the optical fibers connecting nodes will extend for tens of kilometers, making photon loss a critical parameter that must be mitigated. The Quantum Link mitigates the effects of photon loss on the entangling rate and allows for full heralding of entanglement generation.

Furthermore, advanced network applications require the heralded delivery of shared entangled states ready for further use. The Quantum Link addresses this by enabling the qubit systems to store quantum information for extended times and the network system to apply real-time feedback to the qubits upon successful entanglement generation.

What are the Key Features of the Quantum Link?

The Quantum Link has several key features that make it a significant development in the field of quantum internet technology. One of these features is the extensible architecture that enables the nodes to operate fully independently at large distances. This architecture also mitigates the effects of photon loss on the entangling rate and allows for full heralding of entanglement generation.

Another key feature of the Quantum Link is the precise polarization and timing control. This, along with the active stabilization of the relative optical phase between photons emitted from the nodes, enables the use of the loss-resilient single-click protocol for efficient entanglement generation.

The Quantum Link also features parameter monitoring and the generation of entanglement in post-selection. Furthermore, it uses the full network capabilities of heralding and real-time feedback to deliver entangled states shared between the nodes ready for further use.

How Does the Quantum Link Contribute to the Future of Quantum Networking?

The Quantum Link is a significant milestone towards large-scale quantum networking. It establishes a critical capability for future applications and scaling. The Quantum Link’s ability to address key scaling challenges and its compatibility with different qubit systems make it a generic platform for exploring metropolitan-scale quantum networks.

The Quantum Link’s ability to generate, store, and process quantum information on metropolitan scales is a significant advancement in the field of quantum internet technology. This, along with its ability to mitigate the effects of photon loss and deliver heralded shared entangled states, makes it a promising development for the future of quantum networking.

Furthermore, the Quantum Link’s extensible architecture, precise polarization and timing control, and active stabilization of the relative optical phase between photons emitted from the nodes contribute to its potential for efficient entanglement generation. This makes the Quantum Link a key tool for the exploration and development of large-scale quantum networks.

What are the Implications of the Quantum Link for Quantum Internet Technology?

The Quantum Link has several implications for the future of quantum internet technology. Its ability to connect quantum processors at a metropolitan scale could enable novel applications in communication, computing, sensing, and fundamental science.

The Quantum Link’s ability to mitigate the effects of photon loss and deliver heralded shared entangled states could significantly improve the efficiency and reliability of quantum networks. This could lead to the development of more advanced quantum network systems capable of operating at larger scales.

Furthermore, the Quantum Link’s extensible architecture and compatibility with different qubit systems could facilitate the integration of various quantum technologies. This could lead to the development of more versatile and powerful quantum networks, paving the way for the realization of a quantum internet.