Patent ID: 7853020
Filing Date: 2010-12-14
Classification: H04L

Abstract:
1. A method of forming a quantum key by exchanging quantum signals between first and second QKD stations of an actively stabilized QKD system that has a system visibility, comprising: measuring the system visibility between the first and second QKD stations during the exchanging of quantum signals, using an unmodulated, non overlapping classical signal multiplexed with the quantum signals; generating an error signal S setting an error-signal threshold S detecting the quantum signals to form qubits based on the quantum signals; and forming a raw quantum key by storing only below-threshold qubits for which S wherein the QKD system is a phase-encoding system and the quantum signal error is a phase error, generating a final quantum key from the raw quantum key by sifting, error-correcting and privacy amplifying the raw key.