Single-shot discrimination of coherent states beyond the standard quantum limit.

Autor: Thekkadath GS, Sempere-Llagostera S, Bell BA, Patel RB, Kim MS, Walmsley IA
Jazyk: angličtina
Zdroj: Optics letters [Opt Lett] 2021 Jun 01; Vol. 46 (11), pp. 2565-2568.
DOI: 10.1364/OL.421646
Abstrakt: The discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted coherent states at a telecom wavelength. Owing to its dynamic range and high efficiency, we achieve a bit error probability that unconditionally exceeds the standard quantum limit (SQL) by up to 7.7 dB. The improvement to the SQL persists for signals containing up to approximately seven photons on average and is achieved in a single shot (i.e., without measurement feedback), thus making our approach compatible with larger bandwidths.
Databáze: MEDLINE