Method for measuring states of time-bin qubits in a quantum cryptography key distribution system using a time-to-digital converter and a system for the same
AssigneeSDT Inc.
InventorsJiwon Yune, Byungkwon Park
Life of this patent
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Abstract
Disclosed is a quantum cryptography key distribution system. A receiving device of the system includes: a first single-photon detector outputting a data signal including a time-bin encoding pulse indicating a quantum signal; and a TDC receiving a predetermined reference timing signal and the data signal. The TDC is configured to determine a state of a time-bin qubit indicated by the time-bin encoding pulse based on a time difference between a first generation time point of a reference pulse included in the reference timing signal, and a second generation time point of the time-bin encoding pulse generated after the first generation time point.
Claims13
A receiving device of a quantum cryptography key distribution system, the receiving device comprising:
- a data line transmitting a state of a received quantum signal;
- a first single-photon detector connected to the data line;
- and
- a time-to-digital converter (TDC) receiving a predetermined reference timing signal and a data signal output by the first single-photon detector,
- wherein the TDC is configured to determine a time difference between a generation time of a reference pulse included in the reference timing signal, and a generation time of a time-bin encoding pulse included in the data signal, and configured to determine a state of a time-bin qubit indicated by the time-bin encoding pulse by using the time difference.
An electronic device-readable non-volatile recording medium having a binary file including configuration data configured to program a Field Programmable Gate Array (FPGA), which is recorded therein so that an FPGA included in a quantum cryptography key distribution system to configure a digital circuit including
- a signal reception part receiving a data signal output by a first single-photon detector;
- a time difference determination part configured to determine a time difference between a generation time of a reference pulse included in a predetermined reference timing signal, and a generation time of a time-bin encoding pulse included in the data signal;
- and
- a qubit state determination part configured to determine a state of a time-bin qubit indicated by the time-bin encoding pulse by using the time difference.
Dependencies are inferred from the claim text.