Quantum Communication and Quantum Networking. First International Conference, QuantumComm 2009, Naples, Italy, October 26-30, 2009, Revised Selected Papers

Research Article

Enhanced Free Space Beam Capture by Improved Optical Tapers

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  • @INPROCEEDINGS{10.1007/978-3-642-11731-2_13,
        author={Tim Bartley and Bettina Heim and Dominique Elser and Denis Sych and Metin Sabuncu and Christoffer Wittmann and Norbert Lindlein and Christoph Marquardt and Gerd Leuchs},
        title={Enhanced Free Space Beam Capture by Improved Optical Tapers},
        proceedings={Quantum Communication and Quantum Networking. First International Conference, QuantumComm 2009, Naples, Italy, October 26-30, 2009, Revised Selected Papers},
        proceedings_a={QUANTUMCOMM},
        year={2012},
        month={10},
        keywords={Optical taper free space communication beam-jitter atmospheric optics random media quantum key distribution},
        doi={10.1007/978-3-642-11731-2_13}
    }
    
  • Tim Bartley
    Bettina Heim
    Dominique Elser
    Denis Sych
    Metin Sabuncu
    Christoffer Wittmann
    Norbert Lindlein
    Christoph Marquardt
    Gerd Leuchs
    Year: 2012
    Enhanced Free Space Beam Capture by Improved Optical Tapers
    QUANTUMCOMM
    Springer
    DOI: 10.1007/978-3-642-11731-2_13
Tim Bartley,*, Bettina Heim, Dominique Elser, Denis Sych, Metin Sabuncu, Christoffer Wittmann, Norbert Lindlein, Christoph Marquardt, Gerd Leuchs
    *Contact email: t.bartleyl@physics.ox.ac.uk

    Abstract

    In our continuous variable quantum key distribution (QKD) scheme, the homodyne detection set-up requires balancing the intensity of an incident beam between two photodiodes. Realistic lens systems are insufficient to provide a spatially stable focus in the presence of large spatial beam-jitter caused by atmospheric transmission. We therefore present an improved geometry for optical tapers which offer up to four times the angular tolerance of a lens. The effective area of a photodiode can thus be increased, without decreasing its bandwidth. This makes them suitable for use in our free space QKD experiment and in free space optical communication in general.