Quantum receiver beyond the standard quantum limit of coherent optical communication

Kenji Tsujino, Daiji Fukuda, Go Fujii, Shuichiro Inoue, Mikio Fujiwara, Masahiro Takeoka, Masahide Sasaki

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)


The most efficient modern optical communication is known as coherent communication, and its standard quantum limit is almost reachable with current technology. Though it has been predicted for a long time that this standard quantum limit could be overcome via quantum mechanically optimized receivers, such a performance has not been experimentally realized so far. Here we demonstrate the first unconditional evidence surpassing the standard quantum limit of coherent optical communication. We implement a quantum receiver with a simple linear optics configuration and achieve more than 90% of the total detection efficiency of the system. Such an efficient quantum receiver will provide a new way of extending the distance of amplification-free channels, as well as of realizing quantum information protocols based on coherent states and the loophole-free test of quantum mechanics.

Original languageEnglish
Article number250503
JournalPhysical review letters
Issue number25
Publication statusPublished - 2011 Jun 24
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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