Parts | Days | Selection | Search | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 56: Poster IV
Q 56.41: Poster
Thursday, March 5, 2009, 16:30–19:00, VMP 9 Poster
Studies of atmospheric conditions for free space quantum key distribution with coherent polarization states — •Dominique Elser1, Bettina Heim1, Tim Bartley1,2, Christoffer Wittmann1, Denis Sych1, and Gerd Leuchs1 — 1Max-Planck-Institut für die Physik des Lichts, Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Günther-Scharowsky-Str. 1, Bau 24, 91058 Erlangen, Deutschland — 2Physics Department, Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom
We investigate free space quantum key distribution using continuous variables under real atmospheric conditions. More specifically, we transmit weak coherent polarization states over a 100m free space channel on the roof of our institute’s building [1]. The use of a retro-reflector enables us to place Alice’s and Bob’s station on the same optical table. In our scheme, signal and local oscillator are combined in a single spatial mode auto-compensating atmospheric fluctuations and resulting in excellent interference. Furthermore, the local oscillator acts as a spatial and a spectral filter thus allowing for unrestrained daylight operation. We present investigations of the atmospheric channel with respect to excess noise, spatial beam jitter and transmission statistics. Furthermore we report on the first steps of the implementation of a point-to-point link.
[1] D. Elser et al., arXiv:0811.4756 [quant-ph] (2008).