EPS Placement and Lightweight Entanglement Routing for Quantum Data Networks

Entanglement routing in quantum data networks plays a vital role to support various quantum applications. Existing works on entanglement routing either ignored the Entangled Photon Source (EPS) placement issue or simply assumed a pool of EPSes at a centralized location that can provision entanglement over arbitrary quantum links. In this paper, we propose LightER to solve the joint EPS placement and entanglement routing problem based on the assumption that EPSes are distributed over a quantum network, where an EPS, which is co-located with a quantum node, can send one entangled photon at a time to one of the adjacent nodes only. The salient features of LightER include (i) LightER uses a demand-agnostic EPS placement scheme to maximize network throughput and fairness for all feasible entanglement connection (EC) establishment demands, and (ii) most of the requested ECs can be established over their corresponding Entanglement Paths (EPs) determined offline, and only a small percentage of the ECs will be established over EPs that need to be calculated online, resulting in fast and efficient entanglement routing. Extensive simulations show that compared with schemes without proper EPS placement or entanglement routing, LightER can improve the network throughput by up to 215% and 56.2%, respectively.