Abstract
We will review ongoing work at KTH on quantum communication, discussing in particular two projects; long wavelength quantum cryptography, and entangled state manipulations. In order to extend quantum communications to longer distances it is essential to be able to use the low loss telecommunication window at 1550 nm. We, and recently others have for some time worked on quantum cryptography systems in this wavelength region. Much of the effort has been devoted to the investigation of the InGaAs avalanche photo diodes used as single-photon counters, and examples of the performances and systems implications will be given. As a second topic, for quantum communication beyond point-to-point transmission, it is of some interest to investigate the possibilities offered by multi-particle entangled states. Recently, very interesting results are emerging on purification using linear optics manipulations. We will discuss recent theory work on three-particle entangled states of the inequivalent GHZ-classes and the W-classes and the possibility to do entangled-state-assisted transformations between these classes, as well as to consider possible applications.
© 2001 Optical Society of America
PDF ArticleMore Like This
Jian-Wei Pan, Christoph Simon, Caslav Brukner, and Anton Zeilinger
PPE319 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2001
F. Gibson, A. Hening, M. Bourennane, P. Jonsson, T. Tsegaye, E. Sundberg, and A. Karlsson
CThH104 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 1998
J. D. Franson
T5 International Conference on Quantum Information (QIM) 2001