Quantum Cryptography without Switching

Christian Weedbrook, Andrew M. Lance, Warwick P. Bowen, Thomas Symul, Timothy C. Ralph, Ping Koy Lam

Published 2004-05-19, updated 2004-10-23Version 2

We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.