Testing of the Entangled QKD System EPR S405 Quelle (AIT) in Commercial 1550 nm Fiber Network

Copyright © 2014 Damian Melniczuk, Monika Jacak. This is an open access article distributed under the Creative Commons Attri-bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accordance of the Creative Commons Attribution License all Copyrights © 2014 are reserved for SCIRP and the owner of the intellectual property Damian Melniczuk, Monika Jacak. All Copyright © 2014 are guarded by law and by SCIRP as a guardian. In this communication, we report results of running tests on standard telecommunication metropolitan network 1550 nm fiber applied to a quantum channel to EPR S405 Quelle prototype systems installed in National Labor-atory for Quantum Technologies WUT and in CompSecur Wroclaw. Testing was carried out by means of the original design by us and applied special data card collecting parameters of functioning system allowing for as-sessment of quality of quantum channel. We have performed several trials using various configurations of stan-dard 1550 nm fiber patch-cord up to length of 6.5 km with additional usage of various patch-cords with weldings and connectors which typically present in already installed commercial metropolitan communication networks. The implementation of this testing indicated that the rigorous maintenance of photon polarization is required for quantum information exchange upon EPR S405 Quelle functioning. The polarization of optical signal turned out to be, however, very unstable for the tested connection which resulted in very rapid QBER rise precluding prac