title: Sub-shot-noise-limit discrimination of on-off keyed coherent signals via a quantum receiver with a superconducting transition edge sensor.
abstract: We demonstrate a sub-shot-noise-limit discrimination of on-off keyed coherent signals by an optimal displacement quantum receiver in which a superconducting transition edge sensor is installed. Use of a transition edge sensor and a fiber beam splitter realizes high total detection efficiency and high interference visibility of the receiver and the observed average error surpasses the shot-noise-limit in a wider range of the signal power. Our technique opens up a new technology for the sub-shot-noise-limit detection of coherent signals in optical communication channels.
authors.affiliation: National Institute of Information and Communications Technology (NICT) 4-2-1 Nukui-kitamachi, Koganei, Tokyo, 184-8795, Japan. tsujino@qci.jst.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Tsujino
authors.forename: Daiji
authors.initials: D
authors.lastname: Fukuda
authors.forename: Go
authors.initials: G
authors.lastname: Fujii
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Inoue
authors.forename: Mikio
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takeoka
authors.forename: Masahide
authors.initials: M
authors.lastname: Sasaki