Patent ID: 7539314

Claim:
A method of managing quantum signal transmission in a quantum key distribution (QKD) system having QKD stations Bob and Alice using frame synchronization, comprising: forming a stream of quantum signals at Alice; sending a first ready signal from Bob to Alice that defines a start of a first frame of multiple frames each consisting of a set of encoded quantum signals; performing a first encoding of the quantum signals at Alice and transmitting the first-encoded quantum signals to Bob in the first frame; performing a second encoding of the first-encoded quantum signals at Bob and detecting the twice-encoded quantum signals at Bob for the first frame; at Alice, terminating the first encoding of the quantum signals at Alice at the end of the first frame while continuing to form quantum signals that are not included in a subsequent frame; sending a second ready signal from Bob to Alice to initiate at Alice the first-encoding of quantum signals to form the subsequent frame of encoded quantum signals; synchronizing the sending of frames of encoded quantum signals from Alice to Bob by sending synchronization signals from Alice to Bob; and performing qubit indexing that assigns a frame number to each frame and a qubit position of each encoded qubit within each frame.