Interferometry with Faraday mirrors for quantum cryptography

Abstract

Quantum Cryptography over 23km of installed Telecom fiber using a novel interferometer with Faraday mirrors is presented. The interferometer needs no alignment nor polarization control and features 99.8% fringe visibility. A secret key of 20kbit length with a error rate of 1.35% for 0.1 photon per pulse was produced.

8 Pages, including one Postscript Figure, Latex (Revtex style). To be published in Elect. Lett. 7 (27/03/97)