Abstract

Continuous variable Quantum Key Distribution (CVQKD) utilizes bright beams to establish secure communication between two parties via an optical quantum channel such as an optical fiber. One of the main protocols that are practical and promising involves a selection process after the transmission of quantum states, called post-selection based CVQKD. The security of CVQKD using post-selection has been investigated both theoretically [1] and demonstrated experimentally [2]. However, it was subject to one fundamental assumption, namely that the quantum channel must have strictly zero excess noise (i.e. it is shot-noise-limited). In reality, nonlinearities in optical fibers and classical noise of laser beams commonly introduce Gaussian excess noise.

© 2007 IEEE