Jacobs, B. C.Pittman, T.B.Franson, J.D.2020-08-032020-08-03B. C. Jacobs, T. B. Pittman, and J. D. Franson, Quantum relays and noise suppression using linear optics, hys. Rev. A 66, 052307 (2002), DOI:https://doi.org/10.1103/PhysRevA.66.052307https://doi.org/10.1103/PhysRevA.66.052307http://hdl.handle.net/11603/19297Probabilistic quantum nondemolition (QND) measurements can be performed using linear optics and postselection. Here we show how QND devices of this kind can be used in a straightforward way to implement a quantum relay, which is capable of extending the range of a quantum cryptography system by suppressing the effects of detector noise. Unlike a quantum repeater, a quantum relay system does not require entanglement purification or the ability to store photons.6 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.©2002 The American Physical SocietyText