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 non-orthogonal quantum states. In this work, we propose and experimentally demonstrate a new decoding scheme for quadrature phase-shift encoded signals. Our receiver surpasses the standard quantum limit and outperforms all previously known non-adaptive detectors at low input powers. Unlike existing approaches, the receiver only exploits linear optical elements and on-off photo-detection. This circumvents the requirement for challenging feed-forward operations that limit communication transmission rates and can be readily implemented with current technology.
@article{arxiv.2009.03339,
title = {Quantum receiver for phase-shift keying at the single photon level},
author = {Jasminder S. Sidhu and Shuro Izumi and Jonas S. Neergaard-Nielsen and Cosmo Lupo and Ulrik L. Andersen},
journal= {arXiv preprint arXiv:2009.03339},
year = {2021}
}
Comments
11 pages with 10 figures with appendices. Extended analysis. Accepted version