Quantum Receiver for Phase-Shift Keying at the Single-Photon Level

Quantum enhanced receivers are endowed with resources to achieve higher sensitivities than conventional technologies. For application in optical communications, they provide improved discriminatory capabilities for multiple nonorthogonal quantum states. In this work, we propose and experimentally demonstrate a new decoding scheme quadrature phase-shift encoded signals. Our receiver surpasses the standard limit outperforms all previously known nonadaptive detectors at low input powers. Unlike existing approaches, only exploits linear elements on-off photodetection. This circumvents requirement challenging feed-forward operations that communication transmission rates can be readily implemented current technology.3 MoreReceived 11 September 2020Revised 4 January 2021Accepted 21 2021DOI:https://doi.org/10.1103/PRXQuantum.2.010332Published by American Physical Society under terms of Creative Commons Attribution 4.0 International license. Further distribution work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum communicationQuantum information processingQuantum Information