CN116743369A - Quantum key distribution method, transmitting end, receiving end and quantum key distribution system - Google Patents

Quantum key distribution method, transmitting end, receiving end and quantum key distribution system Download PDF

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Publication number
CN116743369A
CN116743369A CN202310868492.5A CN202310868492A CN116743369A CN 116743369 A CN116743369 A CN 116743369A CN 202310868492 A CN202310868492 A CN 202310868492A CN 116743369 A CN116743369 A CN 116743369A
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quantum
light
quantum light
photon
key distribution
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郝鹏磊
陈巍
韩正甫
王双
银振强
何德勇
周政
郭光灿
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University of Science and Technology of China USTC
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University of Science and Technology of China USTC
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
    • H04L9/0852—Quantum cryptography
    • H04L9/0858—Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/70—Photonic quantum communication
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Optics & Photonics (AREA)
  • Optical Communication System (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

The disclosure provides a quantum key distribution method, a transmitting end, a receiving end and a quantum key distribution system, wherein the quantum key distribution method applied to the transmitting end comprises the following steps: based on a time division mode, triggering a plurality of lasers by using a clock signal so that each laser emits one path of initial quantum light, wherein the wavelengths of different lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of the system quantum state and the number of the lasers; generating transition quantum light according to the multiple paths of initial quantum light based on a dense wavelength division multiplexing mode; randomly modulating the transition quantum light to obtain intermediate quantum light; carrying out light attenuation treatment on the intermediate quantum light to obtain a transmitted photon, wherein the light attenuation treatment is used for attenuating the intermediate quantum light into a single-photon-level transmitted photon; transmitting the transmitted photons to the receiving end, so that the receiving end generates detection results according to the transmitted photons.

Description

Quantum key distribution method, transmitting end, receiving end and quantum key distribution system
Technical Field
The present disclosure relates to the field of quantum communication technologies, and more particularly, to a quantum key distribution method applied to a transmitting end, a quantum key distribution method applied to a receiving end, a transmitting end of a quantum key distribution system, a receiving end of a quantum key distribution system, and a quantum key distribution system.
Background
The quantum key distribution technology is based on the principle of the Haisenberg measurement inaccuracy and the physical characteristic that a single photon quantum state cannot be cloned, and the unconditional security encryption technology is realized. The development of quantum key distribution technology has reached the degree of practicality and is widely used in the fields of finance, government affairs, power grid, military and the like. The technical development of current practice is mainly focused on both high-rate and miniaturized directions, and the final goal is to achieve convenient high-rate key distribution.
In order to increase the generation rate of the security key, on one hand, the method can be realized by increasing the repetition frequency of a quantum key distribution system, and a plurality of key modules such as quantum light preparation, modulation and demodulation, interference ring performance, single photon detection and the like all need to increase the rate, but the generated quantum light contrast is insufficient in the process of increasing the quantum light preparation rate, and the problems of insufficient frequency response and low detection signal to noise ratio due to the influence of parasitic inductance and capacitance of an avalanche diode are caused in the process of increasing the quantum light detection rate; on the other hand, due to nonlinear effect in optical fiber transmission, the increase of the wave fraction can cause interference among quantum lights with various wavelengths, so that the safety code rate is reduced. The above factors make the improvement of the code rate of the existing quantum key distribution system insignificant due to the increase of the error rate in the process of improving the code rate by improving the repetition frequency of the system.
Disclosure of Invention
In view of this, the embodiments of the present disclosure provide a quantum key distribution method applied to a transmitting end, a quantum key distribution method applied to a receiving end, a transmitting end of a quantum key distribution system, a receiving end of a quantum key distribution system, and a quantum key distribution system.
An aspect of an embodiment of the present disclosure provides a quantum key distribution method, applied to a transmitting end of a quantum key distribution system, where the method includes:
based on a time division mode, triggering a plurality of lasers by using a clock signal so that each of the lasers emits an initial quantum light, wherein the wavelengths of the different lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of the system quantum state and the number of the lasers;
generating transition quantum light according to the initial quantum light based on the dense wavelength division multiplexing mode;
randomly modulating the transition quantum light to obtain intermediate quantum light;
performing optical attenuation treatment on the intermediate quantum light to obtain a transmission photon, wherein the optical attenuation treatment is used for attenuating the intermediate quantum light into a single-photon-level transmission photon;
transmitting the sending photon to a receiving end, so that the receiving end generates a detection result according to the sending photon.
According to an embodiment of the present disclosure, the generating transition quantum light according to the initial quantum light based on the dense wavelength division multiplexing manner includes:
and carrying out light combination treatment on multiple paths of initial quantum light by utilizing the dense wavelength division multiplexing mode based on a preset time interval to obtain the transition quantum light, wherein the period of the transition quantum light is the same as the preset time interval.
According to an embodiment of the present disclosure, before transmitting the above-mentioned transmission photon, further comprising:
and inputting the transmission photons into an optical isolator so as to transmit the transmission photons output by the optical isolator to the receiving end.
According to an embodiment of the present disclosure, the randomly modulating the transition quantum light to obtain an intermediate quantum light includes:
carrying out random intensity modulation on the transition quantum light by using an intensity modulator to obtain transition quantum light with modulated intensity;
and carrying out random quantum state modulation on the transition quantum light with the modulated intensity by using a first interferometer to obtain the intermediate quantum light.
According to an embodiment of the present disclosure, the performing optical attenuation processing on the intermediate quantum light to obtain a transmitted photon includes:
carrying out optical attenuation treatment on the intermediate quantum light by using a first optical attenuator to obtain a to-be-confirmed transmitted photon, wherein the first optical attenuator comprises a fixed optical attenuator or an electric control optical attenuator;
and determining the to-be-confirmed sending photon as the sending photon under the condition that the quantum level of the to-be-confirmed sending photon is in the single photon level.
According to an embodiment of the present disclosure, the quantum key distribution method further includes:
and under the condition that the quantum level of the to-be-confirmed sent photon is not in the single photon level, carrying out secondary light attenuation processing on the to-be-confirmed sent photon by using a second light attenuator to obtain the sent photon, wherein the second light attenuator comprises a fixed light attenuator or an electric control light attenuator, and the first light attenuator is different from the second light attenuator.
Another aspect of an embodiment of the present disclosure provides a quantum key distribution method, applied to a receiving end of a quantum key distribution system, where the method includes:
acquiring a transmission photon transmitted by a transmitting end, wherein the transmission photon is obtained by carrying out optical attenuation treatment on intermediate quantum light, the intermediate quantum light is obtained by carrying out random modulation on the intermediate quantum light, the intermediate quantum light is generated on the basis of a dense wavelength division multiplexing mode on multiple paths of initial quantum light, and the multiple paths of initial quantum light are transmitted by triggering a plurality of lasers by using clock signals on the basis of a time division mode;
demodulating the transmitted photons by using a second interferometer to obtain demodulated quantum light;
processing the demodulated quantum light based on the dense wavelength division multiplexing mode to obtain multiple paths of quantum light to be analyzed;
and carrying out quantum light detection processing on a plurality of paths of quantum light to be analyzed by using a single photon detector to obtain a detection result.
Another aspect of an embodiment of the present disclosure provides a transmitting end of a quantum key distribution system, including:
the system comprises a plurality of lasers, wherein the lasers generate multiple paths of initial quantum light under the triggering of a clock signal, the wavelengths of the different lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of a system quantum state and the number of the lasers;
the first dense wavelength division multiplexer is used for generating transition quantum light according to the initial quantum light on a plurality of paths based on a dense wavelength division multiplexing mode;
the random modulator is used for carrying out random modulation on the transition quantum light to obtain intermediate quantum light;
and the optical attenuator is used for carrying out optical attenuation processing on the intermediate quantum light to obtain a transmission photon so as to transmit the transmission photon to a receiving end, so that the receiving end generates a detection result according to the transmission photon, wherein the optical attenuation processing is used for attenuating the intermediate quantum light into the transmission photon with single photon magnitude.
Another aspect of an embodiment of the present disclosure provides a receiving end of a quantum key distribution system, including:
the second interferometer is used for demodulating the acquired transmission photons to obtain demodulated quantum light, wherein the transmission photons are transmitted after the transmission end carries out light attenuation treatment on intermediate quantum light, the intermediate quantum light is obtained by carrying out random modulation on transition quantum light, the transition quantum light is generated on multiple paths of initial quantum light based on a dense wavelength division multiplexing mode, and the multiple paths of initial quantum light are emitted by triggering a plurality of lasers by using clock signals based on a time division mode;
the second dense wavelength division multiplexer is used for processing the demodulated quantum light based on the dense wavelength division multiplexing mode to obtain multiple paths of quantum light to be analyzed;
and the single photon detector is used for carrying out quantum light detection processing on the plurality of paths of quantum light to be analyzed to obtain a detection result.
Another aspect of an embodiment of the present disclosure provides a quantum key distribution system, comprising:
the transmitting end;
a channel for transmitting the transmission photons transmitted by the transmitting end;
the receiving end is configured to detect the transmitted photons transmitted by the channel, so as to obtain a detection result.
According to the embodiment of the disclosure, a plurality of lasers are triggered by clock signals based on a time division mode, so that each laser emits one path of initial quantum light, and transition quantum light is generated according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode; then, randomly modulating the transition quantum light to obtain intermediate quantum light; and finally, carrying out light attenuation treatment on the intermediate quantum light to obtain the final transmitted photon for transmission. Due to the fact that quantum light of time division wavelength division is combined with a dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of an avalanche diode in the quantum light detection rate increasing process are solved. Meanwhile, the contrast of the optical pulse is improved through the time division technology of the lasers with multiple wavelengths, meanwhile, interference among quantum lights with all wavelengths is reduced, and the safety code rate is increased in proportion to the number of the wavelengths.
Drawings
The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments thereof with reference to the accompanying drawings in which:
fig. 1 schematically illustrates a flow chart of a quantum key distribution method according to an embodiment of the present disclosure;
FIG. 2 schematically illustrates a schematic diagram of generation of transition quantum light in accordance with an embodiment of the disclosure;
fig. 3 schematically illustrates a flow chart of a quantum key distribution method according to an embodiment of the present disclosure;
fig. 4 schematically illustrates a schematic diagram of generation of quantum light to be resolved according to an embodiment of the disclosure;
fig. 5 schematically illustrates a structural schematic diagram of a quantum key distribution system according to an embodiment of the present disclosure.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is only exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the concepts of the present disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.
Where expressions like at least one of "A, B and C, etc. are used, the expressions should generally be interpreted in accordance with the meaning as commonly understood by those skilled in the art (e.g.," a system having at least one of A, B and C "shall include, but not be limited to, a system having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).
Fig. 1 schematically illustrates a flow chart of a quantum key distribution method according to an embodiment of the present disclosure.
As shown in fig. 1, the quantum key distribution method is applied to a transmitting end of a quantum key distribution system, and includes operations S101 to S105.
In operation S101, based on a time division manner, triggering a plurality of lasers by using a clock signal, so that each laser emits an initial quantum light, wherein the wavelengths of different lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of the system quantum state and the number of lasers;
in operation S102, transition quantum light is generated according to the multiple paths of initial quantum light based on the dense wavelength division multiplexing mode;
in operation S103, the transition quantum light is randomly modulated to obtain intermediate quantum light;
in operation S104, performing optical attenuation processing on the intermediate quantum light to obtain a transmission photon, where the optical attenuation processing is used to attenuate the intermediate quantum light into a transmission photon with a single photon magnitude;
in operation S105, the transmission photon is transmitted to the receiving end, so that the receiving end generates a detection result according to the transmission photon.
According to the embodiment of the disclosure, the emission end triggers the plurality of lasers to emit quantum light by using clock signals, and the quantum light can be a narrow pulse light source generated by the lasers in a gain switching mode, and one laser corresponds to quantum light with one wavelength. Wherein the number of lasers required is determined based on the system quantum state preparation time period and the one-way quantum light generation time period.
According to an embodiment of the present disclosure, n×t initial quantum lights are generated again by a time division manner of a trigger clock, respectively, and transition quantum lights are generated from n paths of initial quantum lights by a Dense Wavelength Division Multiplexing (DWDM) manner. Thereafter, the transition quantum light is randomly modulated, for example, quantum states and intensities, to obtain intermediate quantum light. And carrying out light attenuation treatment on the intermediate quantum light, transmitting photons with single photon magnitude, and transmitting the transmitted photons to a receiving end to be analyzed by the receiving end so as to obtain a corresponding detection result.
According to the embodiment of the disclosure, a plurality of lasers are triggered by clock signals based on a time division mode, so that each laser emits one path of initial quantum light, and transition quantum light is generated according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode; then, randomly modulating the transition quantum light to obtain intermediate quantum light; and finally, carrying out light attenuation treatment on the intermediate quantum light to obtain the final transmitted photon for transmission. Due to the fact that quantum light of time division wavelength division is combined with a dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of an avalanche diode in the quantum light detection rate increasing process are solved. Meanwhile, the contrast of the optical pulse is improved through the time division technology of the lasers with multiple wavelengths, meanwhile, interference among quantum lights with all wavelengths is reduced, and the safety code rate is increased in proportion to the number of the wavelengths.
Fig. 2 schematically illustrates a schematic of generation of transition quantum light according to an embodiment of the disclosure.
According to an embodiment of the present disclosure, based on a dense wavelength division multiplexing manner, generating transition quantum light from multiple paths of initial quantum light includes:
and carrying out light combination treatment on the multiple paths of initial quantum light by using a dense wavelength division multiplexing mode based on a preset time interval to obtain transition quantum light, wherein the period of the transition quantum light is the same as the preset time interval.
According to the embodiment of the present disclosure, the preset time interval T may be specifically set according to actual situations, and may be, for example, 0.1s.
According to the embodiment of the disclosure, as shown in fig. 2, n paths of n×t initial quantum light are combined according to a preset time interval T by using a dense wavelength division multiplexing manner, so as to implement transition quantum light preparation of time division wavelength division with a period of T.
According to an embodiment of the present disclosure, before transmitting the sending photon, further comprising:
the transmission photons are input into the optical isolator to transmit the transmission photons output by the optical isolator to the receiving end.
According to the embodiment of the disclosure, in order to prevent an eavesdropper from stealing a quantum key in a Trojan horse mode, the optical isolator is arranged so that transmitted photons can only enter from the input end of the optical isolator, the transmitted photons received by the receiving end are output from the output end, and quantum light transmitted by the eavesdropper cannot enter the transmitting end from the input end, so that the safety of quantum communication is improved.
According to an embodiment of the present disclosure, the random modulation of the transition quantum light, resulting in an intermediate quantum light, includes:
carrying out random intensity modulation on the transition quantum light by using an intensity modulator to obtain transition quantum light with modulated intensity;
and carrying out random quantum state modulation on the transition quantum light with modulated intensity by using a first interferometer to obtain intermediate quantum light.
According to the embodiment of the disclosure, after the transition quantum light is generated, the intensity of the transition quantum light needs to be randomly modulated by using an intensity modulator, so that the transition quantum light with modulated intensity is obtained, and the transition quantum light with modulated intensity comprises signal state quantum light and decoy state quantum light, wherein the decoy state number can be one or more.
According to an embodiment of the disclosure, the first interferometer performs random quantum state modulation on the transition quantum light after the modulated intensity under the control of the encoder module, thereby obtaining intermediate quantum light.
According to an embodiment of the present disclosure, performing optical attenuation processing on intermediate quantum light to obtain a transmission photon, including:
performing optical attenuation treatment on the intermediate quantum light by using a first optical attenuator to obtain a to-be-confirmed transmitted photon, wherein the first optical attenuator comprises a fixed optical attenuator or an electric control optical attenuator;
in the case where the quantum level of the transmission photon to be confirmed is of the single photon magnitude, the transmission photon to be confirmed is determined as the transmission photon.
According to the embodiment of the disclosure, the intermediate quantum light is subjected to light attenuation processing by using the first light attenuator to obtain the to-be-confirmed transmission photon, and if the quantum level of the to-be-confirmed transmission photon is already a single photon quantum, the to-be-confirmed transmission photon can be determined as the transmission photon, so that the transmission photon is transmitted to the receiving end.
According to an embodiment of the present disclosure, the quantum key distribution method further includes:
and under the condition that the quantum level of the transmitted photon to be confirmed is not in the single photon level, carrying out secondary light attenuation treatment on the transmitted photon to be confirmed by using a second light attenuator to obtain the transmitted photon, wherein the second light attenuator comprises a fixed light attenuator or an electric control light attenuator, and the first light attenuator is different from the second light attenuator.
According to the embodiment of the disclosure, if the quantum level of the to-be-confirmed transmitted photon attenuated by the first optical attenuator does not reach the single photon level, a second optical attenuation process is further required to be performed on the to-be-confirmed transmitted photon by using the second optical attenuator, so that the finally output transmitted photon is of the single photon level.
Fig. 3 schematically illustrates a flow chart of a quantum key distribution method according to an embodiment of the present disclosure. Fig. 4 schematically illustrates a schematic diagram of generation of quantum light to be resolved according to an embodiment of the disclosure.
As shown in fig. 3, the quantum key distribution method is applied to a receiving end of a quantum key distribution system, and includes operations S301 to S304.
In operation S301, a transmission photon sent by a transmitting end is obtained, where the transmission photon is obtained by performing optical attenuation processing on intermediate quantum light, the intermediate quantum light is obtained by performing random modulation on the intermediate quantum light, the intermediate quantum light is generated on the basis of a dense wavelength division multiplexing mode on multiple paths of initial quantum light, and the multiple paths of initial quantum light are sent by triggering a plurality of lasers by using clock signals on the basis of a time division mode;
in operation S302, the transmitted photons are demodulated by using a second interferometer, so as to obtain demodulated quantum light;
in operation S303, the demodulated quantum light is processed based on the dense wavelength division multiplexing mode, so as to obtain multiple paths of quantum light to be analyzed;
in operation S304, the single photon detector is used to perform quantum light detection processing on multiple paths of quantum light to be analyzed, so as to obtain a detection result.
According to the embodiment of the disclosure, after receiving a transmitted photon sent by a transmitting end and obtained by combining quantum light of time division and wavelength division in a dense wavelength division multiplexing mode, a receiving end demodulates a random quantum state of the transmitted photon by using a decoder in a second interferometer and completes interference on an interference light path, so that demodulated quantum light is obtained. And then, processing the demodulated quantum light based on a dense wavelength division multiplexing mode to obtain n paths of quantum light to be analyzed with the period of n multiplied by T, as shown in fig. 4. And finally, respectively carrying out quantum light detection processing on the quantum light to be analyzed with the period of n paths of n multiplied by T by using n single photon detectors, and obtaining detection results.
According to the embodiment of the disclosure, a transmitting end triggers a plurality of lasers by using clock signals based on a time division mode, so that each laser emits one path of initial quantum light, and then generates transition quantum light according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode; then, randomly modulating the transition quantum light to obtain intermediate quantum light; finally, carrying out optical attenuation treatment on the intermediate quantum light to obtain a transmission photon which is finally used for transmission, carrying out demodulation treatment on the transmission photon by a receiving end, then carrying out dense wavelength division multiplexing treatment on the transmission photon, and finally obtaining a detection result by a single photon detector. Due to the fact that quantum light of time division wavelength division is combined with a dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of an avalanche diode in the quantum light detection rate increasing process are solved. Meanwhile, the interference among quantum lights of all wavelengths is weakened through the time division technology of the lasers with multiple wavelengths, the contrast of light pulses is improved, and the safety code rate is increased in proportion to the number of the wavelengths.
Fig. 5 schematically illustrates a structural schematic diagram of a quantum key distribution system 500 according to an embodiment of the present disclosure.
As shown in fig. 5, according to an embodiment of the present disclosure, a transmitting end 510 of a quantum key distribution system 500 includes:
the system comprises a plurality of lasers 511, wherein the lasers 511 generate multiple paths of initial quantum light under the triggering of a clock signal, the wavelengths of different lasers 511 are different, and the time period of the initial quantum light is determined according to the preparation time period of the system quantum state and the number of lasers 511;
a first dense wavelength division multiplexer 512 for generating transition quantum light according to the multiple initial quantum light based on the dense wavelength division multiplexing manner;
a random modulator 513, configured to randomly modulate the transition quantum light to obtain an intermediate quantum light;
and an optical attenuator 514, configured to perform optical attenuation processing on the intermediate quantum light to obtain a transmission photon, so as to transmit the transmission photon to the receiving end 520, so that the receiving end 520 generates a detection result according to the transmission photon, where the optical attenuation processing is used to attenuate the intermediate quantum light into the transmission photon with a single photon magnitude.
According to the embodiment of the present disclosure, when the transmitting end 510 is operated, the laser 511, the first dense wavelength multiplexer 512 and the optical attenuator 514 in the transmitting end 510 are controlled by the transmitting end control logic in the controller, and the random modulator 513 is operated under the control of the encoding driving module controlled by the transmitting end control logic.
According to the embodiment of the disclosure, a plurality of lasers are triggered by clock signals based on a time division mode, so that each laser emits one path of initial quantum light, and transition quantum light is generated according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode; then, randomly modulating the transition quantum light to obtain intermediate quantum light; and finally, carrying out light attenuation treatment on the intermediate quantum light to obtain the final transmitted photon for transmission. Due to the fact that quantum light of time division wavelength division is combined with a dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of an avalanche diode in the quantum light detection rate increasing process are solved. Meanwhile, the contrast of the optical pulse is improved through the time division technology of the lasers with multiple wavelengths, meanwhile, interference among quantum lights with all wavelengths is reduced, and the safety code rate is increased in proportion to the number of the wavelengths.
It should be noted that, in the embodiment of the present disclosure, the transmitting end 510 of the quantum key distribution system 500 corresponds to the quantum key distribution method applied to the transmitting end 510 of the quantum key distribution system 500 in the embodiment of the present disclosure, and the description of the transmitting end 510 of the quantum key distribution system 500 specifically refers to the quantum key distribution method applied to the transmitting end 510 of the quantum key distribution system 500, which is not described herein.
As shown in fig. 5, the receiving end 520 of the quantum key distribution system 500 includes:
a second interferometer 521, configured to demodulate the obtained transmission photon to obtain a demodulated quantum light, where the transmission photon is transmitted after the transmission end 510 performs optical attenuation processing on an intermediate quantum light, the intermediate quantum light is obtained by randomly modulating a transition quantum light, the transition quantum light is generated on the basis of a dense wavelength division multiplexing manner for multiple initial quantum lights, and the multiple initial quantum lights are sent by triggering the multiple lasers 511 with clock signals on the basis of a time division manner;
a second dense wavelength division multiplexer 522, configured to process the demodulated quantum light based on a dense wavelength division multiplexing manner, so as to obtain multiple paths of quantum light to be resolved;
the single photon detector 523 is configured to perform quantum light detection processing on multiple paths of quantum light to be analyzed, so as to obtain a detection result.
In accordance with an embodiment of the present disclosure, when receiving end 520 is in operation, second interferometer 521 within receiving end 520 is controlled by the coded drive module, and receiving end 520 control logic controls the operation of the coded drive module and single photon detector 523.
According to an embodiment of the present disclosure, the transmitting end 510 triggers the plurality of lasers 511 by using clock signals based on a time division manner, so that each laser 511 emits one path of initial quantum light, and then generates transition quantum light according to multiple paths of initial quantum light based on a dense wavelength division multiplexing manner; then, randomly modulating the transition quantum light to obtain intermediate quantum light; finally, the intermediate quantum light is subjected to light attenuation treatment, so that a transmitted photon which is finally used for transmission can be obtained, the transmitted photon is subjected to dense wavelength division multiplexing treatment after being subjected to demodulation treatment by the receiving end 520, and finally, the multi-path quantum light to be analyzed is subjected to quantum light detection treatment by the single photon detector 523, so that a detection result can be obtained. Due to the fact that quantum light of time division wavelength division is combined with a dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of an avalanche diode in the quantum light detection rate increasing process are solved. Meanwhile, the present disclosure reduces interference between quantum lights of various wavelengths by a time division technique of the lasers 511 of various wavelengths, improves contrast of light pulses, and makes a security code rate increase in proportion to the number of wavelengths.
It should be noted that, in the embodiment of the present disclosure, the receiving end 520 portion of the quantum key distribution system 500 corresponds to the quantum key distribution method portion applied to the receiving end 520 of the quantum key distribution system 500 in the embodiment of the present disclosure, and the description of the receiving end 520 portion of the quantum key distribution system 500 specifically refers to the quantum key distribution method portion applied to the receiving end 520 of the quantum key distribution system 500, which is not described herein.
According to an embodiment of the present disclosure, quantum key distribution system 500 includes:
the transmitting end 510;
a channel 530 for transmitting the transmission photons transmitted by the transmitting end 510;
the receiving end 520, the receiving end 520 is configured to detect the transmission photons transmitted by the channel 530, so as to obtain a detection result.
According to an embodiment of the present disclosure, the transmitting end 510 triggers the plurality of lasers 511 by using clock signals based on a time division manner, so that each laser 511 emits one path of initial quantum light, and then generates transition quantum light according to multiple paths of initial quantum light based on a dense wavelength division multiplexing manner; then, randomly modulating the transition quantum light to obtain intermediate quantum light; finally, the intermediate quantum light is subjected to optical attenuation treatment, so that a transmission photon which is finally used for transmission can be obtained, the transmission photon enters the receiving end 520 through the channel 530, the receiving end 520 demodulates the transmission photon and then performs dense wavelength division multiplexing treatment on the transmission photon, and finally, the single photon detector 523 can obtain a detection result.
According to the embodiment of the disclosure, due to the fact that the quantum light of the time division wavelength division is combined with the dense wavelength division multiplexing mode, the problems of insufficient frequency response and low detection signal-to-noise ratio caused by the influence of parasitic inductance and capacitance of the avalanche diode in the process of improving the detection rate of the quantum light are solved. Meanwhile, the present disclosure reduces interference between quantum lights of various wavelengths by a time division technique of the lasers 511 of various wavelengths, improves contrast of light pulses, and makes a security code rate increase in proportion to the number of wavelengths. Meanwhile, high-speed quantum light preparation can be realized through time division of the laser 511 modules with multiple wavelengths in the transmitting end 510, and the problem that the safety key rate is reduced due to the fact that the contrast of light pulses is not high in the process of quantum light preparation acceleration, and the error rate in the system quantum key distribution process is improved is solved.
It should be noted that, in the embodiment of the present disclosure, the quantum key distribution system 500 portion corresponds to the quantum key distribution method portion applied to the transmitting end 510 and the receiving end 520 in the embodiment of the present disclosure, and the detailed description of the quantum key distribution system 500 portion refers to the quantum key distribution method portion applied to the transmitting end 510 and the receiving end 520, respectively, and will not be repeated herein.
The embodiments of the present disclosure are described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the disclosure, and such alternatives and modifications are intended to fall within the scope of the disclosure.

Claims (10)

1. A quantum key distribution method applied to a transmitting end of a quantum key distribution system, the method comprising:
based on a time division mode, triggering a plurality of lasers by using clock signals so that each of the lasers emits one path of initial quantum light, wherein the wavelengths of the different lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of the system quantum state and the number of the lasers;
generating transition quantum light according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode;
randomly modulating the transition quantum light to obtain intermediate quantum light;
performing optical attenuation treatment on the intermediate quantum light to obtain a transmitted photon, wherein the optical attenuation treatment is used for attenuating the intermediate quantum light into a single-photon-level transmitted photon;
transmitting the sending photon to a receiving end, so that the receiving end generates a detection result according to the sending photon.
2. The method of claim 1, wherein the generating transition quantum light from multiple paths of the initial quantum light based on a dense wavelength division multiplexing manner comprises:
and carrying out light combination treatment on multiple paths of initial quantum light by utilizing the dense wavelength division multiplexing mode based on a preset time interval to obtain the transition quantum light, wherein the period of the transition quantum light is the same as the preset time interval.
3. The method of claim 1, wherein prior to transmitting the send photon, further comprising:
and inputting the transmission photons into an optical isolator so as to transmit the transmission photons output by the optical isolator to the receiving end.
4. The method of claim 1, wherein the randomly modulating the transition quantum light to obtain intermediate quantum light comprises:
carrying out random intensity modulation on the transition quantum light by using an intensity modulator to obtain transition quantum light with modulated intensity;
and carrying out random quantum state modulation on the transition quantum light with modulated intensity by using a first interferometer to obtain the intermediate quantum light.
5. The method of claim 1, wherein the performing the optical attenuation process on the intermediate quantum light to obtain the transmitted photon comprises:
performing optical attenuation treatment on the intermediate quantum light by using a first optical attenuator to obtain a to-be-confirmed transmitted photon, wherein the first optical attenuator comprises a fixed optical attenuator or an electric control optical attenuator;
and determining the to-be-confirmed sending photon as the sending photon under the condition that the quantum level of the to-be-confirmed sending photon is of a single photon level.
6. The method of claim 5, further comprising:
and under the condition that the quantum level of the to-be-confirmed sent photon is not single photon level, carrying out secondary light attenuation processing on the to-be-confirmed sent photon by using a second light attenuator to obtain the sent photon, wherein the second light attenuator comprises a fixed light attenuator or an electric control light attenuator, and the first light attenuator is different from the second light attenuator.
7. A quantum key distribution method applied to a receiving end of a quantum key distribution system, the method comprising:
acquiring a transmission photon transmitted by a transmitting end, wherein the transmission photon is obtained by carrying out optical attenuation treatment on intermediate quantum light, the intermediate quantum light is obtained by carrying out random modulation on the intermediate quantum light, the intermediate quantum light is generated on the basis of a dense wavelength division multiplexing mode on multiple paths of initial quantum light, and the multiple paths of initial quantum light are transmitted by triggering a plurality of lasers by using clock signals on the basis of a time division mode;
demodulating the transmitted photons by using a second interferometer to obtain demodulated quantum light;
processing the demodulated quantum light based on the dense wavelength division multiplexing mode to obtain multiple paths of quantum light to be analyzed;
and carrying out quantum light detection processing on a plurality of paths of quantum light to be analyzed by using a single photon detector to obtain a detection result.
8. A sender of a quantum key distribution system, comprising:
the system comprises a plurality of lasers, wherein the lasers generate a plurality of paths of initial quantum light under the triggering of a clock signal, the wavelengths of the lasers are different, and the time period of the initial quantum light is determined according to the preparation time period of a system quantum state and the number of the lasers;
the first dense wavelength division multiplexer is used for generating transition quantum light according to multiple paths of initial quantum light based on a dense wavelength division multiplexing mode;
the random modulator is used for carrying out random modulation on the transition quantum light to obtain intermediate quantum light;
and the optical attenuator is used for carrying out optical attenuation processing on the intermediate quantum light to obtain a sending photon so as to transmit the sending photon to a receiving end, so that the receiving end generates a detection result according to the sending photon, wherein the optical attenuation processing is used for attenuating the intermediate quantum light into the sending photon with single photon magnitude.
9. A receiving end of a quantum key distribution system, comprising:
the second interferometer is used for demodulating the acquired transmitted photons to obtain demodulated quantum light, wherein the transmitted photons are transmitted after the intermediate quantum light is subjected to light attenuation treatment by the transmitting end, the intermediate quantum light is obtained by randomly modulating the transition quantum light, the transition quantum light is generated for multiple paths of initial quantum light based on a dense wavelength division multiplexing mode, and the multiple paths of initial quantum light are emitted by triggering a plurality of lasers by using clock signals based on a time division mode;
the second dense wavelength division multiplexer is used for processing the demodulated quantum light based on the dense wavelength division multiplexing mode to obtain multiple paths of quantum light to be analyzed;
and the single photon detector is used for carrying out quantum light detection processing on a plurality of paths of quantum light to be analyzed to obtain a detection result.
10. A quantum key distribution system comprising:
the transmitting end of claim 8;
a channel for transmitting the transmission photons sent by the transmitting end;
the receiving end of claim 9, wherein the receiving end is configured to detect the transmitted photons transmitted by the channel to obtain a detection result.
CN202310868492.5A 2023-07-14 2023-07-14 Quantum key distribution method, transmitting end, receiving end and quantum key distribution system Pending CN116743369A (en)

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