Method and apparatus for extracting avalanche signals

Abstract

The present invention provides a method and device for extracting an avalanche signal, the method comprising: acquiring an APD signal output by a single-photon detector, the APD signal including an upper peak generated with the rising edge of the gate control signal and a the lower peak generated by the falling edge of the control signal; determine the delay position of the upper peak in the APD signal, so as to determine the delay of the lower peak in the APD signal by the gate width of the gating signal position; move the coincidence gate signal so that the delay position of the falling edge of the coincidence gate signal is aligned with the delay position of the lower peak in the APD signal; compare the result of the comparison between the APD signal and the discrimination threshold with The coincidence gate signal is ANDed to extract the avalanche signal from the APD signal. The invention can effectively avoid the influence of the peak noise caused by the gating signal on the extraction of the avalanche signal, thereby greatly improving the coding rate of the quantum communication system.

Description

technical field [0001] The present invention relates to the technical field of quantum communication, in particular to a method and device for extracting avalanche signals in a quantum communication system. Background technique [0002] Currently, single-photon detectors used in quantum communication systems (such as quantum key distribution systems) mainly detect light pulses carrying encoded information through avalanche diodes (Avalanche Photodiode, APD). [0003] However, in an APD controlled based on gating, due to the existence of the junction capacitance of the APD itself, the APD signal will generate spike noise voltages with the rising and falling edges of the gate pulse, and the intensity of these spike noise voltages is much greater than that caused by The intensity of the avalanche signal triggered by the single photon, so that the avalanche signal may be annihilated by these spike noise voltages and cannot be extracted, thereby reducing the coding rate of the qu...

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Problems solved by technology

[0003] However, in the APD based on gating control, due to the existence of the APD’s own junction capacitance, the APD signal will generate spike noise voltages along with the rising and falling edges of the gating pulse, and the intensity of these spike noise voltages is much greater than that caused by The strength of the avalanche signal triggered by single photon, thus causing the avalanche signal may be annihilated by these spike noise voltages and cannot be extracted, thereby reducing the coding rate of the quantum communication system

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