Transceiver suitable for quantum key scheduling management and quantum key distribution system

Abstract

The invention discloses a receiving and transmitting device suitable for quantum key scheduling management and a quantum key distribution system, and the device comprises a main optical path which is sequentially connected with a first single photon source, a first polarization maintaining circulator, a first polarization maintaining 50 / 50x type optical beam splitter / combiner and a second polarization beam splitter / combiner; a first single photon source outputs a linear polarization single photon pulse to a first polarization maintaining circulator, after beam splitting of a first polarization maintaining 50 / 50x type light beam splitter / combiner, one path enters a second polarization beam splitter / combiner after passing through a quantum state modulation unit, and the other path is directly coupled to the second polarization beam splitter / combiner; the second polarization beam splitter / combiner combines the two paths of pulses into one light path for output; and the quantum state modulation unit performs phase modulation on the pulse according to the agreement of a quantum key protocol, and loads modulation information on the pulse. The problems that in an existing quantum key distribution system, two communication parties are asymmetric in structure, single in function and difficult to schedule and manage in a unified mode are solved.

Description

Technical Field

[0001] The present invention belongs to the field of quantum secure communication, and in particular relates to a transceiver device suitable for quantum key scheduling management and a quantum key distribution system. Background Art

[0002] The 21st century is an information society, and the secure transmission of information has received great attention. In the process of secure transmission of information, information encryption is the most commonly used solution, so the distribution of keys is of paramount importance. Especially as the coverage of mobile communication networks becomes more and more extensive, the number of mobile terminals increases, and the demand for communication security of mobile terminals becomes stronger and stronger. Distributing the quantum keys generated by the quantum key distribution system to mobile terminals can ensure that the confidential communication of mobile terminals reaches an ideal level of security. The implementation scheme and implementation method of quantum key wireless distribution technology are the basis for opening up cross-domain and cross-industry applications and improving the coverage and service scope of quantum security capabilities.

[0003] U.S. Patent No. 5307410 proposed a quantum key distribution system based on a dual unequal-arm Mach-Zehnder (MZ) interferometer, with unidirectional transmission of photons; this scheme effectively prevents Trojan attacks, and the light pulses propagate along different paths inside the interferometers of the two communicating parties. Although later schemes have the application of polarization-maintaining optical fibers, the two light pulses pass through different arms of the unequal-arm Mach-Zehnder interferometer and experience different optical devices. Due to the influence of birefringence of optical fibers and optical devices, it is difficult to ensure the definite relationship between the polarization states of the two light pulses.

[0004] To overcome the defects of the above scheme, for example, A. Muller et al. published "Plug and play" systems for quantum cryptography in Appl. Phys. Lett. (Vol70) in 1997. The first proposed scheme of time-division multiplexing interferometer based on Faraday rotator mirror. The scheme adopts a 90-degree rotating Faraday reflector, and the single photon pulse goes back and forth once between the two communicating parties, traversing all the optical paths of both parties. The polarization dispersion effect of the quantum channel is automatically compensated, thereby eliminating the influence of birefringence of optical fiber and optical devices. At the same time, the polarization-dependent working characteristics of the waveguide phase modulator are solved. However, the defect of this scheme is that when an ideal single photon source is used, since the light pulse has to go back and forth once in the quantum signal, the maximum communication distance is only half of the one-way transmission. The method usually adopted for this scheme is to use strong light on the way out and reduce it to a single photon source on the way back, but the return loss in the optical path increases the bit error rate.

[0005] The Chinese patent application with the application number 200410013996.6 discloses "A Polarization Control Coding Method, Encoder and Quantum Key Distribution System". This solution proposes a quantum key distribution system centered around a polarization control encoder. Due to the reverse photon separation detection device used within the security zones of both communication parties, the symmetry of the functions of both communication parties is disrupted.

[0006] In the above various solutions, due to the asymmetry of the optical path, there can only be one sender and one receiver between the two communication parties, and the functions cannot be interchanged, which brings great obstacles to the scheduling, management, and practical application of quantum keys. In a complex electromagnetic environment, traditional quantum key distribution technology faces challenges. Electromagnetic interference may cause errors and distortions in the transmission and measurement processes of quantum signals, thereby reducing the efficiency and reliability of the quantum key distribution system. Therefore, it is necessary to improve the device to enhance the scheduling and management of quantum keys. In addition, the diversity and complexity of equipment in industrial scenarios such as substations also increase the implementation difficulty of scheduling and management in quantum key distribution. Summary of the Invention

[0007] Object of the Invention: The object of the present invention is to provide a transceiver device and a quantum key distribution system suitable for quantum key scheduling management, to solve the problems of the asymmetric structure and single function of the two communication parties in the existing quantum key distribution system, which are difficult to be uniformly scheduled and managed.

[0008] Technical Solution: A transceiver device suitable for quantum key scheduling management of the present invention includes a main optical path and a quantum state modulation unit. A first single-photon source, a first polarization-maintaining circulator, a first polarization-maintaining 50 / 50x optical beam splitter / combiner, and a second polarization beam splitter / combiner are sequentially connected on the main optical path;

[0009] The first single-photon source outputs linearly polarized single-photon pulses to the first polarization-maintaining circulator. One path of the linearly polarized single-photon pulses after being split by the first polarization-maintaining 50 / 50x optical beam splitter / combiner enters the quantum state modulation unit, and the other path is directly coupled to the polarization-maintaining pigtail of the second polarization beam splitter / combiner; the output end of the quantum state modulation unit is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner, and the second polarization beam splitter / combiner combines the two paths of linearly polarized single-photon pulses into one optical path for output;

[0010] The quantum state modulation unit is used to perform phase modulation on the linearly polarized single-photon pulses according to the agreement of the quantum key protocol during the information receiving or sending process, and load the modulation information on the linearly polarized single-photon pulses.

[0011] Further, the quantum state modulation unit includes a first polarization beam splitter / combiner, a first phase modulator, and a first 90-degree rotating Faraday mirror;

[0012] One polarization-maintaining pigtail of the first polarization beam splitter / combiner is connected to the polarization-maintaining pigtail C port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner. The single-mode fiber output end of the first polarization beam splitter / combiner is connected to the single-mode fiber input end of the first phase modulator. The single-mode fiber output end of the first phase modulator is connected to the first 90-degree rotation Faraday mirror.

[0013] The other polarization-maintaining pigtail of the first polarization beam splitter / combiner is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner.

[0014] Further, the linearly polarized single-photon pulse passes through the first phase modulator twice, and the polarization directions are perpendicular to each other when passing through the first phase modulator twice. The width of the electrical pulse applied to the first phase modulator is greater than the time for the linearly polarized single-photon pulse to pass through the first phase modulator back and forth twice.

[0015] Further, the first phase modulator performs phase modulation on the linearly polarized single-photon pulse according to the agreement of the quantum key protocol and loads the modulation information on the linearly polarized single-photon pulse.

[0016] Further, the input port of the first polarization-maintaining circulator is connected to the first single-photon source. The co-directional output end of the input port is connected to the polarization-maintaining pigtail A port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner. The reverse output end of the input port is connected to the first single-photon detector for single-photon detection.

[0017] Further, the B port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner is connected to the second single-photon detector for single-photon detection.

[0018] Based on the same inventive concept, a quantum key distribution system of the present invention includes two sets of the above transceiver devices applicable to quantum key scheduling management, and the two sets of transceiver devices applicable to quantum key scheduling management are docked with each other. The two sets of transceiver devices applicable to quantum key scheduling management are connected through a quantum channel. One set of transceiver devices applicable to quantum key scheduling management is used to send information, and the other set of transceiver devices applicable to quantum key scheduling management is used to receive information.

[0019] Further, any one of the two sets of transceiver devices applicable to quantum key scheduling management is used as the receiving party, and the other is used as the sending party. Since the instrument composition and layout of the sending party and the receiving party are exactly the same, the robustness of the device and the anti-interference ability in a complex environment are increased.

[0020] Further, both the receiving party and the sending party can perform phase modulation on the uplink linearly polarized single-photon pulse and the downlink linearly polarized single-photon pulse according to the agreement of the quantum key protocol.

[0021] Furthermore, a half-wave plate is provided in the quantum channel. Under the action of the half-wave plate, when reaching the receiving party, compared with the two linearly polarized single-photon pulses with perpendicular polarizations output by the transmitting party, their polarization states are exchanged with each other.

[0022] Beneficial effects: Compared with the prior art, the remarkable technical effects of the present invention are as follows:

[0023] The quantum key distribution system of the present invention integrates the functions of sending and receiving, and has more complete functions: In the existing technology, the functions of the transmitting party and the receiving party are fixed, and their instrument compositions and layouts are also different. That is, the transmitting party can only load information using single-photon pulse signals, and for the backward incoming optical signals, it is either unable to load information or unable to separate from the transmitted signal, which is extremely unfavorable for the practical application of quantum key distribution. In the quantum key distribution system of the present invention, the functions of the transmitting party and the receiving party are completely symmetric, and their instrument compositions and layouts are also exactly the same.

[0024] The loading of the transmitted and received information in the quantum key distribution system of the present invention can be carried out serially or in parallel: In the prior art, due to the single functions of the transmitting party and the receiving party, neither party can complete the task of transmitting and receiving information. The quantum key transmitting and receiving device provided by the present invention enables either party to not only complete the task of transmitting and receiving information, but also the loading of the transmitted and received information can be carried out serially or in parallel.

[0025] The quantum key distribution system of the present invention has automatic polarization compensation and information can be mutually transmitted. The functions, instrument compositions and layouts of both communication parties are exactly the same. The system not only has the function of automatic polarization compensation, but also has good stability and anti-interference ability. While in the existing quantum key distribution system, the functions of both communication parties are single, which affects the quantum key generation rate and application. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of a transceiver device applicable to quantum key scheduling and management disclosed in an embodiment of the present invention;

[0027] Figure 2 It is a schematic structural diagram of a quantum key distribution system disclosed in an embodiment of the present invention. Detailed Embodiments

[0028] The technical solutions of the present invention will be introduced in detail below in conjunction with the detailed embodiments and the accompanying drawings of the specification.

[0029] Embodiment 1

[0030] As Figure 1As shown in the figure, a transceiver device applicable to quantum key scheduling management according to the present invention involves the following components: a first single-photon source 1, a first polarization-maintaining circulator 2, a first single-photon detector 3, a second single-photon detector 4, a first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, a first polarization beam splitter / combiner 6, a first phase modulator 7, a first 90-degree rotating Faraday mirror 8, and a second polarization beam splitter / combiner 9.

[0031] On the main optical path, a first single-photon source 1, a first polarization-maintaining circulator 2, a first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, and a second polarization beam splitter / combiner 9 are connected in sequence. The input port of the first polarization-maintaining circulator 2 is connected to the first single-photon source 1. The co-directional output end of the input port is connected to the polarization-maintaining pigtail A port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, and the reverse output end of the input port is connected to the first single-photon detector 3. The B port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5 is connected to the second single-photon detector 4. The C port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5 is connected to the quantum state modulation unit. The D port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5 is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9.

[0032] In this embodiment, the quantum state modulation unit includes a first polarization beam splitter / combiner 6, a first phase modulator 7, and a first 90-degree rotating Faraday mirror 8. One polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 is connected to the polarization-maintaining pigtail C port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5. The single-mode fiber output end of the first polarization beam splitter / combiner 6 is connected to the single-mode fiber input end of the first phase modulator 7. The single-mode fiber output end of the first phase modulator 7 is connected to the first 90-degree rotating Faraday mirror 8. The other polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9. The quantum state modulation unit is used to perform phase modulation on the linearly polarized single-photon pulse according to the agreement of the quantum key protocol during the information receiving or sending process, and load the modulation information on the linearly polarized single-photon pulse.

[0033] The first single-photon source 1 can be a single-photon source formed by strong attenuation or a true single-photon source.

[0034] The single-photon detector is generally an avalanche photodiode, and it operates in the low-temperature gated Geiger mode to reduce the influence of dark noise and stray light.

[0035] The second polarization beam splitter / combiner 9 on the main optical path can be a Y-shaped optical splitter / combiner.

[0036] The linearly polarized single-photon optical pulse output by the first single-photon source 1 is input into the input port of the first polarization-maintaining circulator 2, and is output from the co-directional output end of the input port, and then enters the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5 from the polarization-maintaining pigtail A port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5; the linearly polarized single-photon pulse is split into two beams by the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, and one of the split linearly polarized single-photon pulses directly enters the second polarization beam splitter / combiner 9 from the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9 from the D port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5. The other split linearly polarized single-photon pulse is coupled into the polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 from the C port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, and then enters the single-mode fiber input end of the first phase modulator 7 from the single-mode fiber output end of the first polarization beam splitter / combiner 6, and enters the first 90-degree rotation Faraday mirror 8 from the single-mode fiber output end of the first phase modulator 7. The linearly polarized single-photon pulse returns along the original path to the first polarization beam splitter / combiner 6. The linearly polarized single-photon pulse passes through the first phase modulator 7 twice, and the polarization directions are perpendicular to each other when passing through the first phase modulator 7 twice. The width of the electrical pulse applied to the first phase modulator 7 is greater than the time for the linearly polarized single-photon pulse to pass through the first phase modulator 7 back and forth twice, thus solving the single-polarization working mode of the waveguide-type phase modulator. The first phase modulator 7 performs phase modulation on the linearly polarized single-photon pulse according to the agreement of the quantum key protocol, and at the same time loads the information to be modulated on the linearly polarized single-photon pulse. The linearly polarized single-photon pulse is phase-modulated according to the agreement of the quantum key protocol. At the same time, relative to the linearly polarized single-photon pulse of the other arm, its polarization direction is also rotated by 90 degrees. The linearly polarized single-photon pulse is output from the other polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 and is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9. In this way, it is combined with the linearly polarized single-photon pulse directly input from the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9 into a single optical path for output. When connecting the polarization-maintaining pigtails between the polarization-maintaining devices, it is required that the fast axis directions of the two connected polarization-maintaining pigtails are the same.

[0037] Embodiment 2

[0038] Such as Figure 2As shown in the figure, a quantum key distribution system of the present invention involves the following components: a first single-photon source 1, a first polarization-maintaining circulator 2, a first single-photon detector 3, a second single-photon detector 4, a first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, a first polarization beam splitter / combiner 6, a first phase modulator 7, a first 90-degree rotating Faraday mirror 8, a second polarization beam splitter / combiner 9, a third polarization beam splitter / combiner 15, a fourth polarization beam splitter / combiner 16, a second phase modulator 17, a second 90-degree rotating Faraday mirror 18, a second polarization-maintaining 50 / 50x optical beam splitter / combiner 19, a second polarization-maintaining circulator 20, a third single-photon detector 21, a fourth single-photon detector 22, a second single-photon source 23, a quantum channel 25, and a half-wave plate 26.

[0039] A quantum key distribution system of the present invention includes two sets of transceiver devices applicable to quantum key scheduling management described in Embodiment 1, and the two sets of transceiver devices applicable to quantum key scheduling management are docked with each other. The two sets of transceiver devices applicable to quantum key scheduling management are connected through a quantum channel 26. One set of transceiver devices applicable to quantum key scheduling management is used to send information, and the other set of transceiver devices applicable to quantum key scheduling management is used to receive information. Any one of the two sets of transceiver devices applicable to quantum key scheduling management serves as the receiver, and the other serves as the sender. The composition and layout of the sender and receiver instruments are exactly the same, and their functions are also exactly the same. Both the receiver and the sender can perform phase modulation on the uplink linearly polarized single-photon pulse and the downlink linearly polarized single-photon pulse according to the agreement of the quantum key protocol, enhancing the robustness of quantum key distribution in a complex electromagnetic environment, facilitating quantum key management and scheduling for both communication parties, and then establishing their cipher books to achieve an unconditional secure distribution system for quantum keys. A half-wave plate 26 may or may not be installed in the quantum channel 26.

[0040] As the sender, the linearly polarized single-photon pulses output by the first single-photon source 1 are input into the input port of the first polarization-maintaining circulator 2, and output from its co-directional output port to port A of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5. The reverse output terminal is connected to the first single-photon detector 3. The second single-photon detector 4 is connected to port B of the first polarization-maintaining 50 / 50x optical beam splitter / combiner. The single-photon detector is generally an avalanche photodiode, and it operates in the cryogenic-gated Geiger mode to reduce the influence of dark noise and stray light. After being split by the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, one path of linearly polarized single-photon pulses directly enters the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9 after coming out from port D of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5. Another path of linearly polarized single-photon pulses enters the polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 from port C of the first polarization-maintaining 50 / 50x optical beam splitter / combiner 5, is output from the single-mode fiber of the first polarization beam splitter / combiner 6, enters the single-mode fiber input end of the first phase modulator 7, and enters the first 90-degree rotating Faraday mirror 8 from the single-mode fiber output end of the first phase modulator 7. The reflected light after being reflected by the first 90-degree rotating Faraday mirror 8 passes through the first phase modulator 7 again and reaches the single-mode pigtail input end of the first polarization beam splitter / combiner 6. The linearly polarized single-photon pulses pass through the first phase modulator 7 twice, and the polarization directions when passing through are perpendicular to each other. The width of the electrical pulse applied to the first phase modulator 7 is greater than the time for the round trip, thus solving the single-polarization working mode of the waveguide-type phase modulator, and at the same time performing phase modulation according to the agreement of the quantum key protocol, and loading the information on the linearly polarized single-photon pulses. It is output from the other polarization-maintaining pigtail of the first polarization beam splitter / combiner 6 and enters the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9. In this way, it is combined with the linearly polarized single-photon pulses directly input into the polarization-maintaining pigtail of the polarization beam splitter / combiner 9 mentioned above to form an optical path and output and couple into the quantum channel, and the polarization directions of the two linearly polarized single-photon pulses are perpendicular to each other.

[0041] After passing through the half-wave plate 26, the quantum channel 25, due to the action of the half-wave plate 26 in the quantum channel, when reaching the receiving party, compared with the two linearly polarized single-photon pulses with perpendicular polarizations output by the transceiver device applicable to quantum key scheduling management at the sending party, their polarization states are exchanged with each other. Input from the single-mode pigtail of the third polarization beam splitter / combiner 15, the two linearly polarized single-photon pulses with perpendicular polarizations respectively enter the two polarization-maintaining pigtails of the third polarization beam splitter / combiner 15. The linearly polarized single-photon pulse that originally passed through the D port of the first polarization-maintaining 50 / 50x type optical beam splitter / combiner 5 to the polarization-maintaining pigtail of the second polarization beam splitter / combiner 9 enters the polarization-maintaining pigtail of the fourth polarization beam splitter / combiner 16 through the polarization-maintaining pigtail of the third polarization beam splitter / combiner 15 at the receiving party, and is coupled into the second phase modulator 17 from the single-mode pigtail of the fourth polarization beam splitter / combiner 16. The single-mode pigtail output of the second phase modulator 17 is connected to the second 90-degree rotating Faraday mirror 18, and the reflected light passes through the second phase modulator 17 again and reaches the input end of the single-mode pigtail of the fourth polarization beam splitter / combiner 16. The linearly polarized single-photon pulse passes through the second phase modulator 17 twice, and the polarization directions when passing through are perpendicular to each other. The pulse width of the pulse modulation voltage applied to the second phase modulator 17 is greater than the time for the round trip. The optical path structure of the present invention overcomes the defect that the commonly used waveguide-type phase modulator can only work in the single-polarization working mode, and at the same time performs phase modulation according to the agreement of the quantum key protocol, and loads the information on the linearly polarized single-photon pulse. It is coupled into the G port of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19 from the other polarization-maintaining pigtail output of the fourth polarization beam splitter / combiner 16, while the other linearly polarized single-photon pulse is coupled into the H port of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19 from the polarization-maintaining pigtail output of the third polarization beam splitter / combiner 15.

[0042] Since the linearly polarized single-photon pulse output from the transmitting end passes through a 90-degree polarization rotator (i.e., the half-wave plate 26) and then enters the quantum channel 25 for propagation, the two linearly polarized single-photon pulses perpendicular to each other are first coupled into the two arms of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19 according to the polarization directions by the polarization beam splitter / combiner 15 at the receiving end. Since the optical path structure at the receiving end is exactly the same as that of the transmitting end. Compared with the transmitting end, due to the 90-degree rotation of the polarization direction, the originally phase-modulated linearly polarized single-photon pulse will no longer be modulated. The originally unmodulated linearly polarized single-photon pulse will be phase-modulated according to the agreement of the quantum key protocol at the receiving end. In this way, when the two linearly polarized single-photon pulses reach the combining point of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19, their polarization directions are the same and the optical paths they travel are also the same, so an interference phenomenon occurs. The interfered linearly polarized single-photon pulse is output from either the E port or the F port of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19, which is related to the phases modulated by the first phase modulator 7 and the second phase modulator 17. The linearly polarized single-photon pulse output from the F port of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19 is detected by the fourth single-photon detector 22. The linearly polarized single-photon pulse output from the E port of the second polarization-maintaining 50 / 50x type optical beam splitter / combiner 19 is coupled into the co-directional output end of the second polarization-maintaining circulator 20 and enters the third single-photon detector 21 for detection from its reverse output end.

[0043] In the above analysis, the receiving end and the transmitting end are defined for the sake of narration.

[0044] In the quantum key distribution system of the present invention, the compositions and arrangements of the instruments at the transmitting end and the receiving end are exactly the same, which increases the robustness of the system and the anti-interference ability in complex environments. The quantum key distribution system of the present invention can realize the automatic compensation of the polarization state of the linearly polarized single-photon pulse. Both parties can perform phase modulation according to the agreement of the quantum key protocol, load the information on the linearly polarized single-photon pulse, which is convenient for the two communication parties to send information to each other, and then establish their cipher books to realize the unconditional secure distribution system of quantum keys. It is widely applied to secure communications, such as military, political, important business intelligence and other fields.

Claims

1. A transceiver device suitable for quantum key scheduling management, characterized in that: It comprises a main optical path and a quantum state modulation unit, wherein the main optical path is connected in sequence to a first single photon source (1), a first polarization-maintaining circulator (2), a first polarization-maintaining 50 / 50x optical beam splitter / combiner (5), and a second polarization beam splitter / combiner (9); The first single-photon source (1) outputs a linearly polarized single-photon pulse to the first polarization-maintaining circulator (2); one path of the linearly polarized single-photon pulse after being split by the first polarization-maintaining 50 / 50x optical splitter / combiner (5) enters the quantum state modulation unit, and the other path is directly coupled to the polarization-maintaining pigtail of the second polarization splitter / combiner (9); the output end of the quantum state modulation unit is connected to the polarization-maintaining pigtail of the second polarization splitter / combiner (9), and the second polarization splitter / combiner (9) combines the two linearly polarized single-photon pulses into one optical path for output; The quantum state modulation unit is used to perform phase modulation on the linearly polarized single photon pulse according to the agreement of the quantum key protocol during information reception or transmission, and load the modulation information on the linearly polarized single photon pulse.

2. The transceiver device suitable for quantum key scheduling management according to claim 1, characterized in that: The quantum state modulation unit comprises a first polarization beam splitter / combiner (6), a first phase modulator (7), and a first 90-degree rotating Faraday reflector (8); A polarization-maintaining pigtail of the first polarization splitter / combiner (6) is connected to the polarization-maintaining pigtail C port of the first polarization-maintaining 50 / 50x optical splitter / combiner (5), the single-mode optical fiber output end of the first polarization splitter / combiner (6) is connected to the single-mode optical fiber input end of the first phase modulator (7), and the single-mode optical fiber output end of the first phase modulator (7) is connected to the first 90-degree rotating Faraday reflector (8); Another polarization-maintaining pigtail of the first polarization beam splitter / combiner (6) is connected to the polarization-maintaining pigtail of the second polarization beam splitter / combiner (9).

3. The transceiver device suitable for quantum key scheduling management according to claim 2, characterized in that: The linearly polarized single-photon pulse passes through the first phase modulator (7) twice, and the polarization directions of the two passes through the first phase modulator (7) are perpendicular to each other, and the width of the electric pulse applied to the first phase modulator (7) is greater than the time it takes for the linearly polarized single-photon pulse to pass through the first phase modulator (7) twice.

4. The transceiver device suitable for quantum key scheduling management according to claim 2, characterized in that: The first phase modulator (7) performs phase modulation on the linearly polarized single photon pulse according to the agreement of the quantum key protocol, and loads the modulation information on the linearly polarized single photon pulse.

5. The transceiver device suitable for quantum key scheduling management according to claim 1, characterized in that: The input port of the first polarization-maintaining circulator (2) is connected to the first single-photon source (1), the same-direction output end of the input port is connected to the polarization-maintaining pigtail A port of the first polarization-maintaining 50 / 50x optical splitter / combiner (5), and the reverse output end of the input port is connected to the first single-photon detector (3).

6. The transceiver device suitable for quantum key scheduling management according to claim 1, characterized in that: The B port of the first polarization-maintaining 50 / 50x optical beam splitter / combiner (5) is connected to the second single-photon detector (4).

7. A quantum key distribution system, characterized in that: The invention comprises two sets of transceiver devices suitable for quantum key scheduling management as claimed in claim 1, and the two sets of transceiver devices suitable for quantum key scheduling management are connected to each other; The two groups of transceiver devices suitable for quantum key scheduling management are connected via a quantum channel (26), one group of transceiver devices suitable for quantum key scheduling management is used to send information, and the other group of transceiver devices suitable for quantum key scheduling management is used to receive information.

8. The quantum key distribution system according to claim 7, characterized in that: Any one of the two groups of transceiver devices suitable for quantum key scheduling management is used as the receiver, and the other group is used as the sender.

9. The quantum key distribution system according to claim 8, characterized in that: The receiver and the transmitter can both perform phase modulation on the uplink linearly polarized single-photon pulse and the downlink linearly polarized single-photon pulse according to the agreement of the quantum key protocol.

10. The quantum key distribution system according to claim 7, characterized in that: A 1 / 2 wave plate (26) is arranged in the quantum channel (26).

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