Single photon detection method based on quantum key distribution
A technology of quantum key distribution and single-photon detection, which is applied in key distribution, can solve the problems of increased cost, delay range not meeting system requirements, and high market price of delay chips, achieving the effect of reducing complexity and cost
Inactive Publication Date: 2017-09-22
ZHEJIANG QUANTUM TECH CO LTD
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[0003] The purpose of the present invention is to provide a single photon detection method based on quantum key distribution, to solve the problem that the available delay range of the general delay chip required for synchronizing the clock signal in the prior art cannot meet the system requirements, and the use of individual can meet the requirements The market price of the delay chip is relatively high, and the method of cascading ordinary chips will not only increase the cost but also increase the technical defect of the system complexity
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[0027] In the quantum key distribution system, the single-photon signal will have an interference peak with a period of 25 ns through attenuation, phase modulation and interference. Since the single-photon and synchronous signals are transmitted through different optical fibers, the delay of the signal is also different. To ensure that the single photon detector accurately detects single photons, it is necessary to perform a 25ns delay scan on the synchronization signal to find an accurate delay time, so that the time when the single photon reaches the detector is the same as the time when the synchronization signal arrives at the detector. Only in this way can the single photon be detected accurately.
[0028] Such as image 3 As shown, the n clock phases can be divided into four phases, respectively 0, π / 2, π, 3π / 2, wherein the clock delay time of the four phases constitutes a whole period T, and T=25ns.
[0029] The delayed clock is used as the trigger clock of the single ...
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The invention provides a single photon detection method based on quantum key distribution. The method comprises a single photon emitter used for generating signal light and synchronous light, the generated synchronous light is processed by a transmitting end central processor to generate a synchronous clock signal, the synchronous clock signal is transmitted to a receiving end through a synchronous signal optical fiber, the synchronous clock signal is used as a detection base clock of a receiving end single photon detector to detect a single photon signal, in the process when the synchronous light is processed by the transmitting end central processor to generate the synchronous clock signal, delay processing is performed on the synchronous clock signal, and the delay time length of the synchronous clock signal is determined on the basis of the detectable single photon signal of the single photon detector. Compared with the prior art, the single photon detection method provided by the invention has the advantages that whole period delay of the single photon signal is realized by phase switching and segmented delayed scanning of the synchronous signal, a high-price chip capable of realizing the delay of dozens of nanoseconds is discarded in the delay process of the synchronous clock signal, and meanwhile the ordinary chip cascading manner is also discarded, thereby not only reducing the cost, but also reducing the redundancy of the system.
Description
technical field [0001] The invention relates to the technical field of quantum key distribution, in particular to a single photon detection method based on quantum key distribution. Background technique [0002] In the process of quantum key distribution, the single-photon signal sent by the sending end of the system must be detected at the receiving end, which requires sending a synchronous clock at the sending end as the base clock for detecting the single-photon signal at the receiving end. Since the single-photon emitter sends a single-photon signal with a relatively long period (tens of nanoseconds), the synchronization signal needs to be delayed the same as or longer than the period to accurately detect the single-photon signal. At present, most of the available delay ranges of programmable delay chips on the market are several nanoseconds to tens of nanoseconds. Even if some chips can achieve a delay of tens of nanoseconds, the price of such chips is relatively high i...
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Inventor 王志愿赵义博
Owner ZHEJIANG QUANTUM TECH CO LTD