Method for collecting snowslide signal of APD single photon detector

Abstract

This invention discloses a method for extracting avalanche signals of the APD single photon detector including the following steps: after the triggering signals pass through a trigger delay unit, part of them is added into the cathode of APD after passing through a gated pulse control unit, then current samples are carried out at the anode to get the original signals, the other part is input into the trigger via the counting delay unit and the control unit, the original signals are sent into the trigger via a comparator as the clock of the trigger, which finishes the pulse extraction of APD avalanche signals triggered by the two parts of signals, part of the extracted pulses is fed back to a dead zone time control unit , the other part outputs signals from the output of the trigger and outputs pulse signals with controlled pulse width via a width control unit.

Description

technical field [0001] The invention relates to quantum cryptography communication, in particular to a method for extracting an avalanche diode (APD) avalanche signal in single photon detection technology. Background technique [0002] Quantum cryptography communication technology is determined by the Heisenberg uncertainty principle in physics. It is completely confidential. It is a communication based on light quantum. The password information is loaded on a single photon and transmitted by a single photon. The unknown quantum state cannot be cloned. Yes, measuring the quantum changes the quantum state, making it impossible for an eavesdropper to eavesdrop on the message without being detected. In quantum secure communication, single-photon detection plays a very important role. The optical signal detection and amplification devices used for single-photon detectors mainly include photomultiplier tubes and avalanche photodiodes. Photomultiplier tubes have low quantum effici...

AI Technical Summary

Problems solved by technology

In quantum secure communication, single photon detection plays a very important role. The optical signal detection and amplification devices used for single photon detectors mainly include photomultiplier tubes and avalanche photodiodes. Photomultiplier tubes have low quantum efficiency in the wavelength range of optical fiber communication. , large noise, and large dark current, and the avalanche photodiode, on the contrary, has the advantages of high quantum detection efficiency, low noise, and small dark current, so that the avalanche photodiode gradually replaces the photomultiplier tube in the quantum cryptography communication system. However, due to The avalanche photodiode itself has distributed capacitance and junction capacitance. The presence of these capacitances will generate differential interference pulses on the rising and falling edges of the gating signal. How to extract the avalanche signal from the differential interference pulses has become a single-photon detection technology. Big difficulty; in addition, after the avalanche of APD, the intrinsic recovery time of the avalanche diode is too long, which becomes a bottleneck affecting the speed of the detector and improving the transmission rate of quantum cryptography communication

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