Post-reception synchronization in a continuous variable quantum key distribution (CV-QKD) system

A continuous variable-quantum key distribution (CV-QKD) transmitter, comprising a memory configured to store a set of program codes, and a processor coupled to the memory, wherein the set of program codes causes the processor to be configured to:

• transmit to a CV-QKD receiver and store, a quantum signal over a communication channel, wherein the quantum signal has a first phase, a first central frequency, a first pulse shape, and a first bandwidth;
• receive, from the CV-QKD receiver, a determined quantum communication channel, a phase shift, a frequency shift, a delay, and a third bandwidth over an authenticated communication channel;
• obtain a modified quantum signal by modifying the stored quantum signal based on the phase shift, the frequency shift, the delay, and the third bandwidth;
• and
• generate a secret key using the modified quantum signal.

A continuous variable-quantum key distribution (CV-QKD) receiver, comprising a memory configured to store a set of program codes, and a processor coupled to the memory, wherein the set of program codes causes the processor to be configured to:

• receive, from a CV-QKD transmitter, a quantum signal over a communication channel, wherein the quantum signal that is transmitted by the CV-QKD transmitter has a first phase, a first central frequency, a first pulse shape, and a first bandwidth, the quantum signal via the communication channel and via a reception band of the CV-QKD receiver, the reception band having a second central frequency and a second bandwidth, wherein the second central frequency is offset from the first central frequency by a frequency shift caused by the communication channel, wherein the received quantum signal has a second phase and a second pulse shape, wherein the second phase is offset from the first phase by a phase shift caused by the communication channel and the second pulse shape is offset from the first pulse shape by a delay caused by the communication channel;
• determine a quantum communication channel based on the received quantum signal, the phase shift, the frequency shift, the delay, and a third bandwidth resulting from an overlap between the first bandwidth around the first central frequency and the second bandwidth around the second central frequency;
• send, to the CV-QKD transmitter, the determined quantum communication channel, the phase shift, the frequency shift, the delay, and the third bandwidth over an authenticated communication channel;
• and
• generate a secret key using the received quantum signal.