Reconfigurable Quantum Internet Service Provider

TL;DR

The paper addresses building scalable, reconfigurable quantum networks by introducing a QISP concept and a testbed (INQUIRE) that unifies quantum hardware and software control. It presents Quagent, a RESTful, Web-based Platform-as-a-Service framework for dynamic resource scheduling and real-time data access, enabling multiple users to share entanglement resources. Experimentally, the authors demonstrate multi-channel entanglement distribution and routing over ~1 km using time-energy entangled photons, with non-local dispersion cancellation validating entanglement; concurrent services for multiple users are tested. The work lays a foundation for architectures and protocols for next-generation quantum networks and provides open-source tools for rapid prototyping.

Abstract

With the recent developments in engineering quantum systems, the realization of scalable local-area quantum networks has become viable. However, the design and implementation of a quantum network is a holistic task that is way beyond the scope of an abstract design problem. As such, a testbed on which multiple disciplines can verify the design and implementation across a full networking stack has become a necessary infrastructure for the future development of quantum networks. In this work, we demonstrate the concept of quantum internet service provider (QISP), in analogy to the conventional ISP that allows for the sharing of classical information between the network nodes. The QISP is significant for the next-generation quantum networks as it coordinates the production, management, control, and sharing of quantum information across the end-users of a quantum network. We construct a reconfigurable QISP comprising both the quantum hardware and classical control software. Building on the fiber-based quantum-network testbed of the Center for Quantum Networks (CQN) at the University of Arizona (UA), we develop an integrated QISP prototype based on a Platform-as-a-Service (PaaS) architecture, whose classical control software is abstracted and modularized as an open-source QISP framework. To verify and characterize the QISP's performance, we demonstrate multi-channel entanglement distribution and routing among multiple quantum-network nodes with a time-energy entangled-photon source. We further perform field tests of concurrent services for multiple users across the quantum-network testbed. Our experiment demonstrates the robust capabilities of the QISP, laying the foundation for the design and verification of architectures and protocols for future quantum networks.

Figures (6)

• Figure 1: The deployed INQUIRE instrumental system serves versatile research and teaching objectives via fiber-based transmission of quantum signals. INQUIRE consists of high-quality EPS and SPD resources and quantum routers controlling photon streams between terminal labs and the hub.
• Figure 2: Layout and configuration of INQUIRE. (a) INQUIRE has a star topology comprised of 5 buildings as hubs and 13 labs as terminal nodes. The central hub (ECE building) is directly or indirectly connected to the 13 nodes located in the Materials Science and Engineering (MSE) building, the Physics-Atmospheric Sciences building (PAS), the College of Optical Science (OSC) building, and the BIO5 Institute (BIO) building. (b) The 5x16 and 8x8 optical switches serve as bandwidth-unlimited quantum routers. Each user is configured with 5 EPS channels and 4 SPD ones. Each 1x16 switch connects one EPS channel to 16 users ($\mathrm{user}_1\sim\mathrm{user}_{16}$); each 1x8 switch connects one SPD channel to 8 users ($\mathrm{user}_1\sim\mathrm{user}_{8}$ or $\mathrm{user}_9\sim\mathrm{user}_{16}$). For EPS resources, each user can access any one of 5 EPS channels but one EPS can be only occupied by one of 16 users at any time; for SPD resources it is similar.
• Figure 3: Brief implementation framework of Quagent.
• Figure 4: Real-time dynamic status of network testbed. Quagent is serving multiple users (lab nodes) simultaneously. Rippling blue nodes represent active users occupying EPS or SPD channel resources; grey nodes represent inactive users; large rippling black circles are hubs located in five buildings while ECE is the central hub. Tailing red circles represent entangled-photon streams; tailing purple circles represent single photons from users to be detected.
• Figure 5: Scheme and result of time-energy entanglement characterization. (a) Setup for testing multi-channel photon routing and the non-local dispersion cancellation. DCF: dispersion compensating fiber; NZDSF: non-zero dispersion-shifted fiber. (b) FWHMs of measured time correlations between the 1570-nm photons and the dispersion-compensated 1550-nm photons traveling from the time-energy entanglement source to User 1. The dispersion compensation applied on 1550-nm photon varies from 0 to $-22$ ps/nm where the minus sign means compensating the fiber's normal dispersion. The error bars represent the uncertainty of Gaussian fitting.