Effect of intensity modulator extinction on practical quantum key distribution system J.Z. Huang, Z.Q. Yin, S. Wang, H.W. Li, W. Chen and Z.F. Han Eur. Phys. J. D, 66 6 (2012) 159 Published online: 29 June 2012 DOI: 10.1140/epjd/e2012-20757-5