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

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, sender, receiver and quantum key distribution system

Technical field

The present disclosure relates to the field of quantum communication technology, and more specifically, to a quantum key distribution method applied to a sending end, a quantum key distribution method applied to a receiving end, a sending end of a quantum key distribution system, and a quantum key distribution system. The receiving end and the quantum key distribution system.

Background technique

Quantum key distribution technology is an unconditionally secure encryption technology based on the Heisenberg uncertainty principle and the physical properties of single-photon quantum states that cannot be cloned. The development of quantum key distribution technology has reached the level of practicality and is widely used in finance, government affairs, power grids, military and other fields. At present, practical technology development is mainly focused on the two directions of high speed and miniaturization. The ultimate goal is to achieve convenient high-speed key distribution.

In order to increase the rate of secure key generation, on the one hand, it can be achieved by increasing the repetition frequency of the quantum key distribution system. Many key modules such as quantum light preparation, modulation and demodulation, interference ring performance and single photon detection all need to increase the rate. However, in quantum In the process of increasing the light preparation rate, there is the problem of insufficient contrast of the generated quantum light. In the process of increasing the quantum light detection rate, there are problems of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode; in addition, On the one hand, due to the nonlinear effect in optical fiber transmission, the increase in the number of wavelength divisions will cause interference between quantum lights of various wavelengths, thereby reducing the security code rate. The above factors make the existing quantum key distribution system in the process of increasing the code rate by increasing the system repetition frequency, but the code rate increase is not significant due to the increase in the bit error rate.

Contents of the invention

In view of this, embodiments of the present disclosure provide a quantum key distribution method applied to the sending end, a quantum key distribution method applied to the receiving end, the sending end of the quantum key distribution system, the receiving end of the quantum key distribution system, and Quantum key distribution system.

One aspect of the embodiments of the present disclosure provides a quantum key distribution method, which is applied to the sending end of the quantum key distribution system. The above method includes:

Based on the time-division method, a clock signal is used to trigger multiple lasers, so that each of the above-mentioned lasers emits an initial quantum light. Different above-mentioned lasers have different wavelengths. The time period of the above-mentioned initial quantum light is based on the system quantum state preparation time period and the laser The quantity is determined;

Based on the dense wavelength division multiplexing method, transition quantum light is generated based on multiple channels of the above initial quantum light;

Randomly modulate the above transition quantum light to obtain intermediate quantum light;

Perform light attenuation processing on the above-mentioned intermediate quantum light to obtain transmitted photons, wherein the above-mentioned light attenuation processing is used to attenuate the above-mentioned intermediate quantum light into single-photon-level transmitted photons;

The above-mentioned sending photon is transmitted to the receiving end, so that the above-mentioned receiving end generates a detection result according to the above-mentioned sending photon.

According to an embodiment of the present disclosure, the above-mentioned method is based on dense wavelength division multiplexing, and the transition quantum light is generated based on multiple channels of the above-mentioned initial quantum light, including:

Based on the preset time interval, multiple channels of the initial quantum light are combined using the dense wavelength division multiplexing method 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 sending photon, it also includes:

The above-mentioned sending photons are input into the optical isolator, so that the above-mentioned sending photons output by the above-mentioned optical isolator are transmitted to the above-mentioned receiving end.

According to embodiments of the present disclosure, the above-mentioned transition quantum light is randomly modulated to obtain intermediate quantum light, including:

Use an intensity modulator to perform random intensity modulation on the above-mentioned transition quantum light to obtain transition quantum light with modulated intensity;

The first interferometer is used to perform random quantum state modulation on the transition quantum light after the modulation intensity to obtain the above intermediate quantum light.

According to an embodiment of the present disclosure, the above-mentioned light attenuation processing is performed on the above-mentioned intermediate quantum light to obtain transmitted photons, including:

Using a first optical attenuator to perform optical attenuation processing on the above-mentioned intermediate quantum light to obtain the photons to be confirmed, wherein the above-mentioned first optical attenuator includes a fixed optical attenuator or an electronically controlled optical attenuator;

In the case where the quantum level of the above-mentioned photon to be transmitted is a single photon level, the above-mentioned photon to be transmitted is determined to be the above-mentioned transmission photon.

According to an embodiment of the present disclosure, the quantum key distribution method further includes:

When the quantum level of the above-mentioned transmission photon to be confirmed is not a single photon level, a second optical attenuator is used to perform a second light attenuation process on the above-mentioned transmission photon to be confirmed to obtain the above-mentioned transmission photon, wherein the above-mentioned second light attenuation The device includes a fixed light attenuator or an electronically controlled light attenuator, and the first light attenuator is different from the second light attenuator.

Another aspect of the embodiment of the present disclosure provides a quantum key distribution method, which is applied to the receiving end of the quantum key distribution system. The above method includes:

Obtain the transmission photons sent by the transmitting end, wherein the above-mentioned transmission photons are obtained by performing light attenuation processing on the intermediate quantum light, the above-mentioned intermediate quantum light is obtained by randomly modulating the transition quantum light, the above-mentioned transition quantum light is based on dense wavelength division The multiplexing method generates multiple channels of initial quantum light. The above-mentioned multiple channels of initial quantum light are emitted by triggering multiple lasers using clock signals based on the time division method;

Use a second interferometer to demodulate the above-mentioned sent photons to obtain demodulated quantum light;

The above demodulated quantum light is processed based on the above dense wavelength division multiplexing method to obtain multiple channels of quantum light to be analyzed;

Single photon detectors are used to perform quantum light detection processing on multiple channels of the above-mentioned quantum light to be analyzed, and the detection results are obtained.

Another aspect of the embodiment of the present disclosure provides a sending end of a quantum key distribution system, including:

Multiple lasers, wherein multiple of the above-mentioned lasers generate multiple channels of initial quantum light under the trigger of a clock signal, wherein the wavelengths of different above-mentioned lasers are different, and the time period of the above-mentioned initial quantum light is based on the system quantum state preparation time period and the laser definite quantity;

The first dense wavelength division multiplexer is used to generate transition quantum light based on multiple channels of the above-mentioned initial quantum light based on the dense wavelength division multiplexing method;

A random modulator is used to randomly modulate the above-mentioned transition quantum light to obtain intermediate quantum light;

An optical attenuator is used to perform light attenuation processing on the above-mentioned intermediate quantum light to obtain transmission photons, so as to transmit the above-mentioned transmission photons to the receiving end, so that the above-mentioned receiving end generates detection results based on the above-mentioned transmission photons, wherein the above-mentioned light attenuation processing is used for The above-mentioned intermediate quantum light is attenuated into the transmitted photon of single photon level.

Another aspect of the embodiment of the present disclosure provides a receiving end of a quantum key distribution system, including:

The second interferometer is used to demodulate the acquired transmitted photons to obtain demodulated quantum light. The above-mentioned transmitted photons are transmitted by the transmitting end after performing light attenuation processing on the intermediate quantum light. The above-mentioned intermediate quantum light is The light is obtained by random modulation of transition quantum light. The above-mentioned transition quantum light is generated based on dense wavelength division multiplexing method to multiple channels of initial quantum light. The above-mentioned multiple channels of initial quantum light are based on time-division method using clock signals to trigger multiple lasers. issued;

The second dense wavelength division multiplexer is used to process the demodulated quantum light based on the above dense wavelength division multiplexing method to obtain multiple channels of quantum light to be analyzed;

A single photon detector is used to perform quantum light detection processing on multiple channels of the above-mentioned quantum light to be analyzed to obtain detection results.

Another aspect of the embodiments of the present disclosure provides a quantum key distribution system, including:

The above-mentioned sending end;

Channel, used to transmit the photons sent by the above-mentioned sending end;

The above-mentioned receiving end is used to detect the transmitted photons transmitted by the channel to obtain the detection result.

According to embodiments of the present disclosure, multiple lasers are triggered by clock signals based on a time division method, so that each laser emits one channel of initial quantum light, and then based on a dense wavelength division multiplexing method, transition quantum light is generated based on the multiple channels of initial quantum light. ;Then the transition quantum light is randomly modulated to obtain the intermediate quantum light; and finally the intermediate quantum light is subjected to light attenuation processing to obtain the sent photons that are ultimately used for transmission. The time-division and wavelength-division quantum light combined with the dense wavelength division multiplexing method solves the problem of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode during the process of increasing the quantum light detection rate. At the same time, the present disclosure improves the contrast of light pulses through time-division technology of lasers of multiple wavelengths, while reducing the interference between quantum lights of each wavelength, so that the security code rate increases in proportion to the number of wavelengths.

Description of drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

Figure 1 schematically shows a flow chart of a quantum key distribution method according to an embodiment of the present disclosure;

Figure 2 schematically shows a schematic diagram of the generation of transition quantum light according to an embodiment of the present disclosure;

Figure 3 schematically shows a flow chart of a quantum key distribution method according to an embodiment of the present disclosure;

Figure 4 schematically shows a schematic diagram of the generation of quantum light to be resolved according to an embodiment of the present disclosure;

Figure 5 schematically shows a structural diagram of a quantum key distribution system according to an embodiment of the present disclosure.

Detailed ways

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for convenience of explanation, numerous specific details are set forth to provide a comprehensive understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. Furthermore, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. The terms "comprising," "comprising," and the like, as used herein, indicate the presence of stated features, steps, operations, and/or components but do not exclude 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 here should be interpreted to have meanings consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

Where an expression similar to "at least one of A, B, C, etc." is used, it should generally be interpreted in accordance with the meaning that a person skilled in the art generally understands the expression to mean (e.g., "having A, B and C "A system with at least one of" shall include, but is not limited to, systems with A alone, B alone, C alone, A and B, A and C, B and C, and/or systems with A, B, C, etc. ).

Figure 1 schematically shows a flow chart of a quantum key distribution method according to an embodiment of the present disclosure.

As shown in Figure 1, the quantum key distribution method is applied to the sending end of the quantum key distribution system, and the method includes operations S101 to S105.

In operation S101, multiple lasers are triggered using a clock signal based on the time division method, so that each laser emits an initial quantum light. Different lasers have different wavelengths. The time period of the initial quantum light is based on the system quantum state preparation time period and The number of lasers is determined;

In operation S102, based on dense wavelength division multiplexing, transition quantum light is generated based on multiple channels of initial quantum light;

In operation S103, the transition quantum light is randomly modulated to obtain intermediate quantum light;

In operation S104, the intermediate quantum light is subjected to light attenuation processing to obtain transmitted photons, wherein the light attenuation processing is used to attenuate the intermediate quantum light into single photon-level transmitted photons;

In operation S105, the sending photon is transmitted to the receiving end, so that the receiving end generates a detection result according to the sending photon.

According to embodiments of the present disclosure, the transmitting end uses a clock signal to trigger multiple lasers to emit quantum light. The quantum light can be a narrow pulse light source generated by the laser in the gain switching mode. One laser corresponds to one wavelength of quantum light. Among them, the number of lasers required is determined based on the system quantum state preparation time period and the single-channel quantum light generation time period.

According to embodiments of the present disclosure, n×T initial quantum lights are generated again by triggering the clock in a time-division manner, and transition quantum light is generated based on n channels of initial quantum light through dense wavelength division multiplexing (DWDM). Thereafter, the transition quantum light is randomly modulated, such as the quantum state and intensity, to obtain intermediate quantum light. The intermediate quantum light is subjected to light attenuation processing, and photons are sent at the single photon level. The sent photons are transmitted to the receiving end and can be analyzed by the receiving end, and the corresponding detection results are obtained.

According to embodiments of the present disclosure, multiple lasers are triggered by clock signals based on a time division method, so that each laser emits one channel of initial quantum light, and then based on a dense wavelength division multiplexing method, transition quantum light is generated based on the multiple channels of initial quantum light. ;Then the transition quantum light is randomly modulated to obtain the intermediate quantum light; and finally the intermediate quantum light is subjected to light attenuation processing to obtain the sent photons that are ultimately used for transmission. The time-division and wavelength-division quantum light combined with the dense wavelength division multiplexing method solves the problem of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode during the process of increasing the quantum light detection rate. At the same time, the present disclosure improves the contrast of light pulses through time-division technology of lasers of multiple wavelengths, while reducing the interference between quantum lights of each wavelength, so that the security code rate increases in proportion to the number of wavelengths.

Figure 2 schematically shows a schematic diagram of the generation of transition quantum light according to an embodiment of the present disclosure.

According to embodiments of the present disclosure, transition quantum light is generated based on multiple channels of initial quantum light based on dense wavelength division multiplexing, including:

Based on the preset time interval, multiple channels of initial quantum light are combined using dense wavelength division multiplexing to obtain transition quantum light, where the period of the transition quantum light is the same as the preset time interval.

According to embodiments of the present disclosure, the preset time interval T can be specifically set according to actual conditions, for example, it can be 0.1s.

According to an embodiment of the present disclosure, as shown in Figure 2, n channels of n×T initial quantum lights are combined according to a preset time interval T through dense wavelength division multiplexing to realize time-wavelength transition quantum light with a period of T. Light preparation.

According to an embodiment of the present disclosure, before transmitting the photon, it further includes:

The transmit photon is input into the optical isolator to transmit the transmit photon output by the optical isolator to the receiving end.

According to an embodiment of the present disclosure, in order to prevent eavesdroppers from stealing quantum keys through Trojan horses, the present disclosure sets up an optical isolator so that sending photons can only enter from the input end of the optical isolator and output from the output end to the receiving end. The received photon is sent, while the quantum light sent by the eavesdropper cannot enter the sending end from the input end, thereby improving the security of quantum communication.

According to embodiments of the present disclosure, the transition quantum light is randomly modulated to obtain intermediate quantum light, including:

Use an intensity modulator to perform random intensity modulation on the transition quantum light to obtain the transition quantum light after modulation intensity;

The first interferometer is used to perform random quantum state modulation on the transition quantum light after modulating the intensity to obtain intermediate quantum light.

According to embodiments of the present disclosure, after the transition quantum light is generated, an intensity modulator needs to be used to randomly modulate the intensity of the transition quantum light, thereby obtaining transition quantum light with modulated intensity. The transition quantum light with modulated intensity includes a signal state. Quantum light and decoy state quantum light, in which the number of decoy states can be one or more.

According to an embodiment of the present disclosure, the first interferometer performs random quantum state modulation on the transition quantum light after modulation intensity under the control of the encoder module, thereby obtaining the intermediate quantum light.

According to embodiments of the present disclosure, light attenuation processing is performed on the intermediate quantum light to obtain transmitted photons, including:

Using a first optical attenuator to perform optical attenuation processing on the intermediate quantum light to obtain the photons to be sent, wherein the first optical attenuator includes a fixed optical attenuator or an electronically controlled optical attenuator;

In the case where the quantum level of the photon to be sent is the single photon level, the photon to be sent is determined to be the photon to be sent.

According to an embodiment of the present disclosure, the first optical attenuator is used to perform light attenuation processing on the intermediate quantum light to obtain the photon to be confirmed. If the quantum level of the photon to be confirmed is already a single photon quantum, the photon to be confirmed can be sent. The photon is determined to be a sending photon, and the sending photon is sent to the receiving end.

According to an embodiment of the present disclosure, the quantum key distribution method further includes:

When the quantum level of the photon to be confirmed to be sent is not the single photon level, the second optical attenuator is used to perform a secondary light attenuation process on the photon to be sent to be confirmed to obtain the sent photon, wherein the second optical attenuator includes a fixed light attenuation or an electronically controlled optical attenuator, and the first optical attenuator and the second optical attenuator are different.

According to embodiments of the present disclosure, if the quantum level of the photon to be sent after being attenuated by the first optical attenuator does not reach the single photon level, it is necessary to use the second optical attenuator to perform secondary light attenuation of the photon to be sent. Processing so that the final output of the transmitted photon is in the order of a single photon.

Figure 3 schematically shows a flow chart of a quantum key distribution method according to an embodiment of the present disclosure. Figure 4 schematically shows a schematic diagram of the generation of quantum light to be resolved according to an embodiment of the present disclosure.

As shown in Figure 3, the quantum key distribution method is applied to the receiving end of the quantum key distribution system, and the method includes operations S301 to S304.

In operation S301, the transmission photon sent by the transmitting end is obtained, wherein the transmission photon is obtained by performing light attenuation processing on the intermediate quantum light, the intermediate quantum light is obtained by randomly modulating the transition quantum light, and the transition quantum light is based on the dense wave Multiple channels of initial quantum light are generated in the division multiplexing method. The multiple channels of initial quantum light are emitted by triggering multiple lasers using clock signals based on the time division method;

In operation S302, the second interferometer is used to demodulate the transmitted photons to obtain demodulated quantum light;

In operation S303, the demodulated quantum light is processed based on dense wavelength division multiplexing to obtain multiple channels of quantum light to be analyzed;

In operation S304, a single photon detector is used to perform quantum light detection processing on multiple channels of quantum light to be analyzed, and a detection result is obtained.

According to an embodiment of the present disclosure, after the receiving end receives the transmitted photons obtained by combining time-division and wavelength-division quantum light with dense wavelength division multiplexing from the transmitting end, the receiving end uses the decoder in the second interferometer to perform The random quantum state is demodulated and interference is completed on the interference light path, thereby obtaining the demodulated quantum light. After that, the demodulated quantum light is processed based on the dense wavelength division multiplexing method to obtain n channels of quantum light to be analyzed with a period of n×T, as shown in Figure 4. Finally, n single photon detectors are used to perform quantum light detection processing on n channels of quantum light to be analyzed with a period of n×T, and the detection results can be obtained.

According to an embodiment of the present disclosure, the transmitting end uses a clock signal to trigger multiple lasers based on a time division method, so that each laser emits one channel of initial quantum light, and then generates a transition based on the multiple channels of initial quantum light based on a dense wavelength division multiplexing method. Quantum light; then the transition quantum light is randomly modulated to obtain the intermediate quantum light; finally, the intermediate quantum light is subjected to light attenuation processing to obtain the final sent photon for transmission. The receiving end demodulates the sent photon and then After dense wavelength division multiplexing processing, the final detection result can be obtained by a single photon detector. The time-division and wavelength-division quantum light combined with the dense wavelength division multiplexing method solves the problem of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode during the process of increasing the quantum light detection rate. At the same time, the present disclosure uses the time-division technology of lasers of multiple wavelengths to weaken the interference between quantum lights of each wavelength, improve the contrast of light pulses, and increase the security code rate in proportion to the number of wavelengths.

Figure 5 schematically shows a structural diagram of a quantum key distribution system 500 according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, as shown in Figure 5, the sending end 510 of the quantum key distribution system 500 includes:

Multiple lasers 511, wherein multiple lasers 511 generate multiple channels of initial quantum light under the trigger of a clock signal, wherein different lasers 511 have different wavelengths, and the time period of the initial quantum light is based on the system quantum state preparation time period and the laser 511 The quantity is determined;

The first dense wavelength division multiplexer 512 is used to generate transition quantum light based on multiple channels of initial quantum light based on dense wavelength division multiplexing;

Random modulator 513 is used to randomly modulate transition quantum light to obtain intermediate quantum light;

The optical attenuator 514 is used to perform light attenuation processing on the intermediate quantum light to obtain the sending photon, so as to transmit the sending photon to the receiving end 520, so that the receiving end 520 generates a detection result based on the sending photon, wherein the light attenuation processing is used to convert the intermediate quantum light into Quantum light decays into single photon-level transmitted photons.

According to the embodiment of the present disclosure, when the transmitting end 510 is working, the laser 511, the first dense wavelength division multiplexer 512 and the optical attenuator 514 in the transmitting end 510 are all controlled by the transmitting end control logic in the controller. The random modulator 513 works under the control of the encoding driver module controlled by the transmitter control logic.

According to embodiments of the present disclosure, multiple lasers are triggered by clock signals based on a time division method, so that each laser emits one channel of initial quantum light, and then based on a dense wavelength division multiplexing method, transition quantum light is generated based on the multiple channels of initial quantum light. ;Then the transition quantum light is randomly modulated to obtain the intermediate quantum light; and finally the intermediate quantum light is subjected to light attenuation processing to obtain the sent photons that are ultimately used for transmission. The time-division and wavelength-division quantum light combined with the dense wavelength division multiplexing method solves the problem of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode during the process of increasing the quantum light detection rate. At the same time, the present disclosure improves the contrast of light pulses through time-division technology of lasers of multiple wavelengths, while reducing the interference between quantum lights of each wavelength, so that the security code rate increases in proportion to the number of wavelengths.

It should be noted that the sending end 510 part of the quantum key distribution system 500 in the embodiment of the present disclosure and the quantum key distribution method part applied to the sending end 510 of the quantum key distribution system 500 in the embodiment of the present disclosure are: Correspondingly, the description of the sending end 510 of the quantum key distribution system 500 specifically refers to the quantum key distribution method applied to the sending end 510 of the quantum key distribution system 500, which will not be described again here.

As shown in Figure 5, the receiving end 520 of the quantum key distribution system 500 includes:

The second interferometer 521 is used to demodulate the acquired transmitted photons to obtain demodulated quantum light. The transmitted photons are transmitted by the transmitting end 510 after performing light attenuation processing on the intermediate quantum light. The intermediate quantum light is Light is obtained by randomly modulating transition quantum light. Transition quantum light is generated based on dense wavelength division multiplexing of multiple channels of initial quantum light. Multiple channels of initial quantum light are generated based on time division using clock signals to trigger multiple lasers 511. dispatched;

The second dense wavelength division multiplexer 522 is used to process the demodulated quantum light based on dense wavelength division multiplexing to obtain multiple channels of quantum light to be analyzed;

The single photon detector 523 is used to perform quantum light detection processing on multiple channels of quantum light to be analyzed to obtain detection results.

According to an embodiment of the present disclosure, when the receiving end 520 is working, the second interferometer 521 in the receiving end 520 is controlled by the encoding driving module, and the receiving end 520 control logic controls the operation of the encoding driving module and the single photon detector 523 .

According to an embodiment of the present disclosure, the transmitting end 510 uses a clock signal to trigger multiple lasers 511 based on a time division method, so that each laser 511 emits one channel of initial quantum light, and then based on the dense wavelength division multiplexing method, based on the multiple channels of initial quantum light The light generates transitional quantum light; then the transitional quantum light is randomly modulated to obtain intermediate quantum light; finally, the intermediate quantum light is subjected to light attenuation processing to obtain the transmitted photons that are ultimately used for transmission, and the receiving end 520 demodulates the transmitted photons. After processing, it is subjected to dense wavelength division multiplexing processing, and finally the single photon detector 523 performs quantum light detection processing on multiple channels of quantum light to be analyzed to obtain the detection results. The time-division and wavelength-division quantum light combined with the dense wavelength division multiplexing method solves the problem of insufficient frequency response and low detection signal-to-noise ratio due to the influence of the parasitic inductance and capacitance of the avalanche diode during the process of increasing the quantum light detection rate. At the same time, the present disclosure uses the time-division technology of lasers 511 of multiple wavelengths to weaken the interference between quantum lights of each wavelength, improve the contrast of light pulses, and increase the security code rate in proportion to the number of wavelengths.

It should be noted that the receiving end 520 part of the quantum key distribution system 500 in the embodiment of the present disclosure and the quantum key distribution method part applied to the receiving end 520 of the quantum key distribution system 500 in the embodiment of the present disclosure are: Correspondingly, the description of the receiving end 520 of the quantum key distribution system 500 specifically refers to the quantum key distribution method applied to the receiving end 520 of the quantum key distribution system 500, which will not be described again here.

According to an embodiment of the present disclosure, the quantum key distribution system 500 includes:

The above-mentioned sending end 510;

Channel 530 is used to transmit the sending photons sent by the sending end 510;

The above-mentioned receiving end 520 is used to detect the transmitted photons transmitted through the channel 530 to obtain the detection result.

According to an embodiment of the present disclosure, the transmitting end 510 uses a clock signal to trigger multiple lasers 511 based on a time division method, so that each laser 511 emits one channel of initial quantum light, and then based on the dense wavelength division multiplexing method, based on the multiple channels of initial quantum light The light generates transitional quantum light; then the transitional quantum light is randomly modulated to obtain intermediate quantum light; finally, the intermediate quantum light is subjected to light attenuation processing to obtain the final sent photon for transmission, and the sent photon enters the receiving end 520 through channel 530 , the receiving end 520 demodulates the sent photons and then performs dense wavelength division multiplexing on them, and finally the single photon detector 523 can obtain the detection result.

According to embodiments of the present disclosure, time-division and wavelength-division quantum light combined with dense wavelength division multiplexing solves the problem of insufficient frequency response and detection signal-to-noise ratio caused by the parasitic inductance and capacitance of avalanche diodes in the process of increasing the quantum light detection rate. Not a high question. At the same time, the present disclosure uses the time-division technology of lasers 511 of multiple wavelengths to weaken the interference between quantum lights of each wavelength, improve the contrast of light pulses, and increase the security code rate in proportion to the number of wavelengths. At the same time, high-speed quantum light preparation can be achieved through time division of the laser 511 modules of multiple wavelengths in the transmitter 510, which solves the problem of low light pulse contrast in the speed-up of quantum light preparation, resulting in an increase in the bit error rate of the system's quantum key distribution process. The problem caused by the reduction of security key rate.

It should be noted that the quantum key distribution system 500 part in the embodiment of the present disclosure corresponds to the quantum key distribution method part respectively applied to the sending end 510 and the receiving end 520 in the embodiment of the present disclosure. The description of the distribution system 500 part specifically refers to the quantum key distribution method part applied to the sending end 510 and the receiving end 520 respectively, and will not be described again here.

The embodiments of the present disclosure have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment is described separately above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present 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.