Abstract: Systems and associated methods of performing coherent optical communication of quantum information between an emitter A and a distant receiver B are provided, using a local local oscillator. Examples of LLO-based Continuous-Variable Quantum Key Distribution are described. Self-coherent schemes are used, the schemes consisting in deriving both signal and phase reference pulses from the same optical pulse thus ensuring an intrinsic strong signal to reference phase coherence. Different CV-QKD designs implementing various self-coherence phase sharing schemes are described and compared in terms of secret key rate and hardware requirements. Strong phase noise resilience can be obtained with standard telecom equipment such as low cost lasers.

Abstract: A method of communicating a classical message M between a first party A and a second distant party B over a public channel F, comprises the steps of sharing a key between the parties, the shared key K comprising a short-term-secure key KS and/or a long-term-secure key KL; at A, encoding M as a quantum codeword, A using K to encode M into a first encrypted codeword belonging to a publicly known quantum code; communicating the first encrypted codeword from A to B over F whose output is a second codeword; unitarily transforming the second codeword into a third codeword by using a N-mode interferometer controlled by B, placed at the output of F and keyed by K; determining an estimate of M, at B, by performing a measurement on the third codeword and by processing the measurement using K.

Abstract: Systems and associated methods of performing coherent optical communication of quantum information between an emitter A and a distant receiver B are provided, using a local local oscillator. Examples of LLO-based Continuous-Variable Quantum Key Distribution are described. Self-coherent schemes are used, the schemes consisting in deriving both signal and phase reference pulses from the same optical pulse thus ensuring an intrinsic strong signal to reference phase coherence. Different CV-QKD designs implementing various self-coherence phase sharing schemes are described and compared in terms of secret key rate and hardware requirements. Strong phase noise resilience can be obtained with standard telecom equipment such as low cost lasers.

Abstract: A method of communicating a classical message M between a first party A and a second distant party B over a public channel F, comprises the steps of sharing a key between the parties, the shared key K comprising a short-term-secure key KS and/or a long-term-secure key KL; at A, encoding M as a quantum codeword, A using K to encode M into a first encrypted codeword belonging to a publicly known quantum code; communicating the first encrypted codeword from A to B over F whose output is a second codeword; unitarily transforming the second codeword into a third codeword by using a N-mode interferometer controlled by B, placed at the output of F and keyed by K; determining an estimate of M, at B, by performing a measurement on the third codeword and by processing the measurement using K.