Scaling quantum photonics networks

Stefano Paesani

Liang Huang, Ying‐Cheng Lai

Recently, small-scale quantum communication has been realized by transporting entangled photons, rendering potentially feasible quantum networks on large scales. We propose a class of quantum networks comprising quantum repeaters for long-distance information transport and local networks of fibers and switches. As the transmitting capability is limited by the node bandwidth, photon loss can occur through the dynamical process of cascading when the network is under external perturbations. We obtain results that can be used to guide quantum network design to minimize the photon loss.

Thomas P. Pearsall

Ravitej Uppu, Tom A. W. Wolterink, Willem L. Vos +2 more

Summary form only given. Quantum optics experiments require ultimate control over the propagation of light in linear optical networks to realize programmable photon correlations [1]. Integrated optics provides a robust and low-loss platform for implementing such linear optical networks. However, to achieve ultimate control on the quantum state of light, it is necessary to program the network [2]. Tuning the network for controlled multiphoton correlations involves optimization algorithms which scale inefficiently with the network size and photon number. Therefore, it is challenging to scale up this approach to massively multichannel networks, which are required for large-scale implementations of quantum information processing and quantum communication.Here, we propose a novel method to achieve ultimate control on quantum light propagation through the adaptive control of phases at input channels of a massively multichannel network. We utilize an on-chip array of 3300 nearest-neighbor coupled silicon nitride waveguides as the network. We employ complex wavefront shaping methods, which enabled the creation of programmable linear optical networks in opaque scattering media [3,4], to realize a network with programmable quantum correlations in a fixed network [5]. Using a high brightness photon-pair source, we demonstrate programmable Hong-Ou-Mandel-like bunching or antibunching of photons in a fully tunable multichannel network as predicted by our theoretical work [6]. These results enable programmable photon correlations on fixed massively multichannel optical networks with the potential for large-scale implementation of quantum simulators and quantum logic gates. We will report on the progress of this project.

Thomas P. Pearsall

Le Luo, David Hayes, T.A. Manning +5 more

Abstract Quantum networks based on atomic qubits and scattered photons provide a promising way to build a large‐scale quantum information processor. We review quantum protocols for generating entanglement and operating gates between two distant atomic qubits, which can be used for constructing scalable atom–photon quantum networks. We emphasize the crucial role of collecting light from atomic qubits for large‐scale networking and describe two techniques to enhance light collection using reflective optics or optical cavities. A brief survey of some applications for scalable and efficient atom–photon networks is also provided.