Building a global quantum internet using a satellite constellation with inter-satellite links

Abstract: The quantum internet is a global network to distribute entanglement and communicate quantum information with applications in cybersecurity, quantum computing, and quantum sensing. Here, we propose building a quantum internet using a constellation of low-Earth-orbit satellites equipped with inter-satellite laser links. Our proposal is based on the downlink model of photon transmission, where satellites carry entangled photon sources and/or have a mirror relay system to redirect the photon path in space. We show that few MHz entanglement distribution rates are possible between the US, Europe, and Asia, with a multiplexed entangled-photon source generating pairs at 10 GHz. Our proposal demonstrates the importance of passive optics in realizing a satellite-based quantum internet, which reduces dependency on quantum memory and repeater technologies.