DOI: 10.1007/978-3-642-11731-2_13
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Tim Bartley, Bettina Heim, Dominique Elser, Denis Sych, Metin Sabuncu, Christoffer Wittmann, Norbert Lindlein, Christoph Marquardt, Gerd Leuchs

Abstract: 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 inc…

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