Hannover 2016 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 42: Poster: Quantum Optics and Photonics III
Q 42.40: Poster
Wednesday, March 2, 2016, 16:30–19:00, Empore Lichthof
Quantum Receivers for Coherent Communication — •Sourav Chatterjee1,2, Christian R. Müller1,2, Gerd Leuchs1,2, and Christoph Marquardt1,2 — 1Max Planck Institute for the Science of Light, Erlangen, Germany — 2Department of Physics, University of Erlangen-Nuremberg (FAU), Germany
The impossibility of perfectly discriminating non-orthogonal states is vital for quantum key-distribution. In classical communication, however, it imposes strict constraints on channel capacity. Conventional receiver architectures for coherent state alphabets are approaching their sensitivity limit -the standard quantum limit (SQL). Quantum mechanics allows for a much lower error bound compared to SQL, the Helstrom bound. This imposes a need for innovations on receiver technologies. Optimal and near-optimal strategies have been proposed and experimentally demonstrated for binary phase-shift keying (BPSK) [1]. For quadrature phase-shift keying (QPSK), a hybrid receiver, based on a combination of homodyne and single photon detection, was demonstrated to outperform the SQL for any signal power [2]. Moreover, a near-optimal, feedback supplemented strategy with photon number resolution technology was proposed in our group [3], and research is in progress to realize this receiver experimentally. We review the recent progress on quantum receivers and compare different strategies on performance and robustness against technical imperfections.
[1] C. Wittmann et al., Phys. Rev. Lett. 101, 210501 (2008) [2] C. R. Müller et al., New J. Phys. 14, 083009 (2012) [3] C. R. Müller et al., New J. Phys. 17, 032003 (2015)