Patent ID: 7274791
Filing Date: 2007-09-25
Classification: H04L

Abstract:
1. A quantum cryptographic receiver, comprising: a beamsplitter that receives an incoming coherent state from a sender and splits said incoming coherent state into at least first and second separate coherent states; at least one photodetector, associated with said beamsplitter, that is positioned with respect to said first and second separate coherent states to detect a presence of a photon in said first and second separate coherent states at a particular phase, said receiver configured to employ said presence to reveal information originated by said sender; and a delay line, associated with said beamsplitter, that receives and delays said first coherent beam thereby to allow said at least one photodetector to detect said presence of said photon in said first coherent beam based on whether said at least one photodetector detects said presence of said photon in said second coherent beam.