Phys.org February 10, 2023
Satellite-based quantum links have been proposed to extend the network domain for quantum communication. An international team of researchers (USA – Oak Ridge National Laboratory, University of Illinois, Singapore) developed a quantum communication system, suitable for realistic satellite-to-ground communication and executed an entanglement-based quantum key distribution (QKD) protocol achieving quantum bit-error rates (QBERs) below 2% in all bases. They demonstrated low-QBER execution of a higher-dimensional hyperentanglement-based QKD protocol, using photons simultaneously entangled in polarization and time bin, leading to significantly higher secure key rates, at the cost of increased technical complexity and system size. They showed that the protocol is suitable for a space-to-ground link, after incorporating Doppler-shift compensation, and verified its security using a rigorous finite-key analysis. They also discussed system-engineering considerations relevant to those and other quantum communication protocols and their dependence on what photonic degrees of freedom are utilized… read more. TECHNICAL ARTICLEÂ
The measured QBER versus the mean number of pairs per pulse… Credit: Phys. Rev. Applied 18, 044027, 12, October 2022