title: Experimental implementation of a quantum optical state comparison amplifier.
abstract: We present an experimental demonstration of a practical nondeterministic quantum optical amplification scheme that employs two mature technologies, state comparison and photon subtraction, to achieve amplification of known sets of coherent states with high fidelity. The amplifier uses coherent states as a resource rather than single photons, which allows for a relatively simple light source, such as a diode laser, providing an increased rate of amplification. The amplifier is not restricted to low amplitude states. With respect to the two key parameters, fidelity and the amplified state production rate, we demonstrate significant improvements over previous experimental implementations, without the requirement of complex photonic components. Such a system may form the basis of trusted quantum repeaters in nonentanglement-based quantum communications systems with known phase alphabets, such as quantum key distribution or quantum digital signatures.
authors: SUPA, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot Watt University, David Brewster Building, Edinburgh EH14 4AS, United Kingdom.
authors: Ross J
authors: RJ
authors: Donaldson
authors: SUPA, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot Watt University, David Brewster Building, Edinburgh EH14 4AS, United Kingdom.
authors: Robert J
authors: RJ
authors: Collins
authors: SUPA, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, United Kingdom.
authors: Electra
authors: E
authors: Eleftheriadou
authors: SUPA, School of Physics and Astronomy, University of Glasgow, Kelvin Building, University Avenue, Glasgow G12 8QQ, United Kingdom.
authors: Stephen M
authors: SM
authors: Barnett
authors: SUPA, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG, United Kingdom.
authors: John
authors: J
authors: Jeffers
authors: SUPA, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot Watt University, David Brewster Building, Edinburgh EH14 4AS, United Kingdom.
authors: Gerald S
authors: GS
authors: Buller