Quantum state encoding device, method and software-defined quantum communication system

Abstract

The present application provides a quantum state encoding device, method, and software-defined quantum communication system. The quantum state encoding device includes: a time phase encoding unit, a first optical coupling unit, an unequal-arm polarization control interferometer, a first transmission optical path, and a second optical coupling unit. The time phase encoding unit is used to generate optical pulses in a time phase-encoded quantum state; the unequal-arm polarization control interferometer is used to convert the optical pulses in the time phase-encoded quantum state into optical pulses in a polarization-encoded quantum state. By controlling the first and second optical coupling units to select output optical pulses in a polarization-encoded quantum state or output optical pulses in a time phase-encoded quantum state according to quantum communication coding control instructions, the present application enables the same quantum state encoding device to meet the different coding requirements of a quantum communication system.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication and optical quantum coding technology, and in particular to a quantum state coding device, method and software-defined quantum communication system. Background Art

[0002] Quantum communication technology is a cutting-edge field at the intersection of quantum physics and information science. Current applications primarily include quantum key distribution (QKD) and quantum direct communication (QDC). Based on physical principles such as the Heisenberg uncertainty relation in quantum mechanics and the quantum no-cloning theorem, QKD enables real-time and secure key sharing between communicating parties. Quantum direct communication ensures secure information transmission. Quantum communication can detect potential eavesdropping on communication channels and has applications in defense, government, finance, electricity, and other sectors requiring high-security information transmission.

[0003] The physical implementation of quantum communication systems, such as quantum key distribution and quantum direct communication, requires encoding and decoding of quantum states. Currently, practical quantum communication system encoding methods primarily include polarization encoding and time phase encoding. A quantum communication system typically uses only one of these encoding methods, making the system less versatile and inflexible in networking.

[0004] How to combine multiple quantum communication coding methods in the same optical quantum coding device and realize the on-demand generation of time phase encoding and polarization encoding quantum states is an important issue in current quantum communication applications. Summary of the Invention

[0005] The present application provides a quantum state encoding device, method and software-defined quantum communication system to solve the technical problems mentioned in the prior art.

[0006] According to a first aspect of the present application, a quantum state encoding device is provided, comprising: a time phase encoding unit, a first optical coupling unit, an unequal-arm polarization control interferometer, a first transmission optical path, and a second optical coupling unit;

[0007] The temporal phase encoding unit comprises at least one input port and an output port, wherein the temporal phase encoding unit is configured to input an optical pulse through the input port, generate an optical pulse of a temporal phase encoded quantum state based on the optical pulse, and output the optical pulse through the output port;

[0008] The first optical coupling unit comprises an input port and two output ports, namely a first port, a second port and a third port, wherein the first port is connected to the output port of the time phase encoding unit;

[0009] The second optical coupling unit comprises two input ports and one output port, namely a fourth port, a fifth port and a sixth port;

[0010] The unequal-arm polarization control interferometer includes an input port and an output port, which is used to perform polarization coding conversion on an input light pulse in a time-phase-coded quantum state and output a light pulse in a polarization-coded quantum state;

[0011] The third port of the first optical coupling unit is connected to the input port of the unequal-arm polarization control interferometer, and the output port of the unequal-arm polarization control interferometer is connected to the fifth port of the second optical coupling unit to form a first optical output branch;

[0012] The second port of the first optical coupling unit is connected to the fourth port of the second optical coupling unit through the first transmission optical path to form a second optical output branch;

[0013] The first optical coupling unit is configured to input the optical pulse of the time phase coded quantum state output by the time phase coding unit into the first optical output branch and / or the second optical output branch according to a quantum communication coding control instruction, wherein the quantum communication coding control instruction is determined according to the coding requirements of the quantum communication system;

[0014] The sixth port of the second optical coupling unit is the output port of the quantum state encoding device, which is used to output the time phase encoded quantum state optical pulse transmitted by the second optical output branch or the polarization encoded quantum state optical pulse output by the first optical output branch according to the quantum communication coding control instruction.

[0015] In some embodiments, the first optical coupling unit is an optical coupler, and the second optical coupling unit is an optical switch.

[0016] In some embodiments, the first optical coupling unit is configured to input the optical pulse of the time phase coded quantum state output by the time phase encoding unit through the first port, split the optical pulse of the time phase coded quantum state into two sub-optical pulses, and input the two sub-optical pulses into the first optical output branch and the second optical output branch through the third port and the second port, respectively;

[0017] The second optical coupling unit is used to select, according to the quantum communication coding control instruction, to output the optical pulse of the time phase coded quantum state transmitted by the second optical output branch or the optical pulse of the polarization coded quantum state output by the first optical output branch.

[0018] In some embodiments, the first optical coupling unit is an optical switch, and the second optical coupling unit is an optical switch or an optical coupler.

[0019] In some embodiments, the first optical coupling unit is configured to selectively input the optical pulse of the time phase coded quantum state into the first optical output branch or the second optical output branch according to the quantum communication coding control instruction;

[0020] When the second optical coupling unit is optically switched, the second optical coupling unit is configured to connect the first optical output branch for outputting the optical pulse of the polarization-encoded quantum state or the second optical output branch for outputting the optical pulse of the time-phase-encoded quantum state according to the quantum communication coding control instruction;

[0021] When the second optical coupling unit is an optical coupler, the second optical coupling unit is used to output the optical pulse in the polarization-encoded quantum state output by the first optical output branch or the optical pulse in the time-phase-encoded quantum state transmitted by the second optical output branch.

[0022] In some embodiments, the unequal-arm polarization control interferometer comprises: a third optical coupling unit, a fourth optical coupling unit, a second transmission optical path, and a third transmission optical path.

[0023] The third optical coupling unit includes at least three ports, one input port and two output ports; the fourth optical coupling unit includes at least three ports, two input ports and one output port; the two output ports of the third optical coupling unit are connected to the two input ports of the fourth optical coupling unit through the second transmission optical path and the third transmission optical path; the input port of the third optical coupling unit is the input port of the unequal-arm polarization control interferometer, and the output port of the fourth optical coupling unit is the output port of the unequal-arm polarization control interferometer; the optical path lengths of the second transmission optical path and the third transmission optical path are not equal.

[0024] In some embodiments, the third optical coupling unit and the fourth optical coupling unit are the same optical coupler, and the unequal-arm polarization control interferometer further includes: two reflecting mirrors,

[0025] The two output ports of the optical coupler are respectively connected to one end of the second transmission optical path and one end of the third transmission optical path, and the two reflectors are respectively connected to the other end of the second transmission optical path and the other end of the third transmission optical path.

[0026] In some embodiments, one of the two mirrors is a 90° polarization rotating mirror.

[0027] In some embodiments, the third optical coupling unit and the fourth optical coupling unit are the same polarization beam splitter, and the unequal-arm polarization control interferometer further includes: two reflecting mirrors,

[0028] The two output ports of the polarization beam splitter are respectively connected to one end of the second transmission light path and one end of the third transmission light path, and the two reflectors are respectively connected to the other end of the second transmission light path and the other end of the third transmission light path.

[0029] In some embodiments, both of the two reflectors are 90° polarization rotating reflectors.

[0030] In some embodiments, the third optical coupling unit and the fourth optical coupling unit are the same optical coupler, and the unequal-arm polarization control interferometer further includes: two reflectors and two polarizers.

[0031] The two output ports of the optical coupler are respectively connected to one end of the second transmission optical path and one end of the third transmission optical path, and the two reflectors are respectively connected to the other end of the second transmission optical path and the other end of the third transmission optical path; the two polarizers are respectively arranged on the second transmission optical path and the third transmission optical path, and the polarization directions of the two polarizers are orthogonal to each other.

[0032] In some embodiments, the 90° polarization rotation mirror is a quarter wave plate mirror or a 90° Faraday rotation mirror.

[0033] In some embodiments, the third optical coupling unit is an optical coupler, and the fourth optical coupling unit is an optical coupler or a polarization combiner.

[0034] In some embodiments, the second transmission optical path or the third transmission optical path is a 90° twisted polarization-maintaining optical fiber, or

[0035] The unequal-arm polarization control interferometer further includes a 90° polarization state rotator, which is arranged in the second transmission optical path or the third transmission optical path and is used to rotate the polarization state of the input sub-light pulse by 90°.

[0036] In some embodiments, the third optical coupling unit is an optical coupler, the fourth optical coupling unit is an optical coupler, and the unequal-arm polarization control interferometer further includes: two polarizers,

[0037] The two polarizers are respectively arranged on the second transmission light path and the third transmission light path, and the polarization directions of the two polarizers are orthogonal to each other.

[0038] In some embodiments, the third optical coupling unit is a polarization beam splitter, and the fourth optical coupling unit is an optical coupler or a polarization beam combiner.

[0039] According to a second aspect of the present application, a quantum state encoding method is provided, which is applied to the above-mentioned quantum state encoding device to implement quantum state encoding.

[0040] According to a third aspect of the present application, a software-defined quantum communication system is provided, comprising the above-mentioned quantum state encoding device and encoding controller;

[0041] The coding controller is used to generate quantum communication coding control instructions based on the coding requirements of the quantum communication system and send them to the quantum state coding device.

[0042] In summary, the quantum state encoding device, method, and quantum communication system provided by this application have at least the following beneficial effects:

[0043] The present application uses a time phase encoding unit, a first optical coupling unit, an unequal-arm polarization control interferometer, a first transmission optical path, and a second optical coupling unit to form a quantum state encoding device, wherein the time phase encoding unit can generate a light pulse of a time phase-encoded quantum state, and the unequal-arm polarization control interferometer can convert the light pulse of the time phase-encoded quantum state into a light pulse of a polarization-encoded quantum state. The first optical coupling unit and the second optical coupling unit can control the output of the light pulse of the time phase-encoded quantum state or the output of the light pulse of the polarization-encoded quantum state according to the quantum communication coding control instruction. Therefore, the quantum state encoding device described in the embodiment of the present application flexibly implements multiple quantum communication coding methods of time phase-encoded quantum state and polarization-encoded quantum state, and realizes that the same quantum state encoding device can meet the different coding requirements of the quantum communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 A block diagram of a quantum state encoding device provided in an embodiment of the present application;

[0046] Figure 2 A diagram illustrating the architecture of a first embodiment of a quantum state encoding device provided in an embodiment of the present application;

[0047] Figure 3 A diagram illustrating an architecture of a second embodiment of a quantum state encoding device provided in an embodiment of the present application;

[0048] Figure 4 A diagram illustrating an architecture of a third embodiment of a quantum state encoding device provided in an embodiment of the present application;

[0049] Figure 5A structural diagram of a first embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0050] Figure 6 A structural diagram of a second embodiment of the unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0051] Figure 7 A structural diagram of a third embodiment of the unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0052] Figure 8 A structural diagram of a fourth embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0053] Figure 9 A structural diagram of a fifth embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0054] Figure 10 A structural diagram of a sixth embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0055] Figure 11 A structural diagram of a seventh embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0056] Figure 12 A structural diagram of an eighth embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0057] Figure 13 A structural diagram of a ninth embodiment of an unequal-arm polarization control interferometer provided in an embodiment of the present application;

[0058] Figure 14 Schematic diagram of the software-defined quantum communication system structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the above and other features and advantages of the present application more clear, the present application is further described below with reference to the accompanying drawings. It should be understood that the specific embodiments given herein are for the purpose of explaining to those skilled in the art and are only exemplary and not restrictive.

[0060] In the following description, many specific details are set forth to provide a thorough understanding of the present application. However, it will be apparent to those skilled in the art that it is not necessary to adopt the specific details to practice the present application. In other cases, well-known steps or operations are not described in detail to avoid obscuring the present application.

[0061] This application proposes a quantum state encoding device, such as Figure 1The figure shows a structural block diagram of a quantum state encoding device provided in an embodiment of the present application, wherein the device includes: a time phase encoding unit 100, a first optical coupling unit 200, an unequal-arm polarization control interferometer 300, a first transmission optical path 400, and a second optical coupling unit 500.

[0062] In some embodiments, the time phase encoding unit 100 includes at least one input port and one output port. The time phase encoding unit 100 is used to input an optical pulse through one of the input ports, generate an optical pulse in a time phase encoded quantum state based on the input optical pulse, and output it through the output port. The optical pulse in the time phase encoded quantum state may include two time slots, which are two time slot sub-optical pulses separated in the time domain; or the time phase encoded quantum state may include only one time slot, which is one of the two time slot sub-optical pulses separated in the time domain (the previous time slot sub-optical pulse or the next time slot sub-optical pulse). The polarization states of the two time slot sub-optical pulses may be the same or orthogonal to each other.

[0063] It should be noted that the time phase encoding described in the embodiments of the present application includes phase encoding, that is, the time phase encoding is an encoding composed of any combination of quantum states of the X phase basis, the Y phase basis, and the Z time basis.

[0064] The embodiment of the present application does not impose any specific limitation on the structure of the time phase encoding unit 100 , which may be any structure that can achieve the function.

[0065] Refer to the attached Figure 2 The figure shows the architecture of the first embodiment of the quantum state encoding device provided by the embodiment of the present application, wherein the first optical coupling unit 200 includes one input port and two output ports, namely the first port A, the second port B, and the third port C. The first port A is connected to the output port of the time phase encoding unit 100. The second optical coupling unit 500 includes two input ports and one output port, namely the fourth port B', the fifth port C', and the sixth port A'.

[0066] Refer again to the attached Figure 2 The unequal-arm polarization control interferometer 300 includes an input port and an output port. The unequal-arm polarization control interferometer 300 is used to perform polarization encoding conversion on the input optical pulse of the time phase encoded quantum state and output the optical pulse of the polarization encoded quantum state. The input port of the unequal-arm polarization control interferometer 300 is used to receive the optical pulse of the time phase encoded quantum state output by the first optical coupling unit 200, and the output port of the unequal-arm polarization control interferometer 300 is used to output the optical pulse of the polarization encoded quantum state after the polarization encoding conversion by the unequal-arm polarization control interferometer 300.

[0067] The third port C of the first optical coupling unit 200 is connected to the input port of the unequal-arm polarization control interferometer 300. The output port of the unequal-arm polarization control interferometer 300 is connected to the fifth port C' of the second optical coupling unit 500 to form a first optical output branch.

[0068] The second port B of the first optical coupling unit 200 is connected to the fourth port B′ of the second optical coupling unit 500 through the first transmission optical path 400 to form a second optical output branch.

[0069] The first optical coupling unit 200 is used to input the optical pulse of the time phase coded quantum state output by the time phase coding unit into the first optical output branch and / or the second optical output branch according to the quantum communication coding control instruction, and the quantum communication coding control instruction is determined according to the coding requirements of the quantum communication system.

[0070] The sixth port A' of the second optical coupling unit 500 is the output port of the quantum state encoding device. In the embodiment of the present application, the second optical coupling unit 500 can be used to output the optical pulse of the time phase-encoded quantum state output by the second optical output branch or the optical pulse of the polarization-encoded quantum state output by the first optical output branch according to the quantum communication coding control instruction.

[0071] It should be noted that quantum communication coding control instructions can be issued by the host computer software. For example, when the first optical coupling unit and the second optical coupling unit are both optical switches, according to the coding requirements of the quantum communication system, the host computer software is run by the control processor in the quantum communication system to issue quantum communication coding control instructions to configure the gating state of the optical switch, thereby realizing the selective output of polarization-encoded quantum state light pulses or time-phase-encoded quantum state light pulses.

[0072] In the above embodiment, a time phase encoding unit 100, a first optical coupling unit 200, an unequal-arm polarization control interferometer 300, a first transmission optical path 400, and a second optical coupling unit 500 are used to form a quantum state encoding device, wherein the time phase encoding unit 100 can generate a light pulse of a time phase encoded quantum state, and the unequal-arm polarization control interferometer 300 can convert the light pulse of the time phase encoded quantum state into a light pulse of a polarization encoded quantum state. The first optical coupling unit 200 and the second optical coupling unit 500 can control the output of the light pulse of the time phase encoded quantum state or the output of the light pulse of the polarization encoded quantum state according to the quantum communication coding control instruction. Therefore, the quantum state encoding device described in the embodiment of the present application flexibly implements multiple quantum communication coding methods of time phase encoded quantum state and polarization encoded quantum state, so that the same quantum state encoding device can meet the different coding requirements of the quantum communication system.

[0073] In one embodiment, the first optical coupling unit 200 is an optical coupler, and the second optical coupling unit 500 is an optical switch. The optical coupler can be a free-space crystal coupler or a fiber coupler, used to split the optical pulses. The optical switch can selectively output the encoded quantum state transmitted by one optical output branch by connecting or disconnecting the optical switch.

[0074] When the first optical coupling unit 200 is an optical coupler, the first optical coupling unit 200 is used to input the optical pulse of the time phase coded quantum state output by the time phase coding unit 100 through the first port A, and split the optical pulse of the time phase coded quantum state into two sub-optical pulses, and input the two sub-optical pulses into the first optical output branch and the second optical output branch respectively through the third port C and the second port B.

[0075] In this embodiment, the second optical coupling unit 500 is configured to selectively output an optical pulse in a time-phase-encoded quantum state output by the second optical output branch or an optical pulse in a polarization-encoded quantum state output by the first optical output branch, based on the quantum communication coded control instruction. In this embodiment, the second optical coupling unit 500 is an optical switch that can flexibly switch the connection between the second optical output branch and the first optical output branch based on the quantum communication coded control instruction, thereby selectively outputting an optical pulse in a time-phase-encoded quantum state output by the second optical output branch or an optical pulse in a polarization-encoded quantum state output by the first optical output branch.

[0076] In the above embodiment, the beam splitting of the first optical coupling unit 200 allows the optical pulse of the time-phase-encoded quantum state to be split into two paths, respectively fed into the first optical output branch and the second optical output branch. Furthermore, the selection function of the second optical coupling unit 500 allows the optical output branch to be switched according to the coding requirements of the quantum communication system. In this way, quantum states with different coding schemes can be selectively output, improving the flexibility and adaptability of the quantum communication system. Furthermore, the advantages of both coding schemes can be fully utilized to ensure the adaptability of quantum states to the communication channel during quantum communication, thereby improving the security and reliability of the quantum communication system. Furthermore, it facilitates the integration of new coding schemes, thereby supporting new communication protocols and higher-performance quantum state transmission.

[0077] In another embodiment, the first optical coupling unit 200 is an optical switch, and the second optical coupling unit 500 is an optical switch.

[0078] When the first optical coupling unit 200 is an optical switch, the optical pulse in the time phase coded quantum state can be selectively input to the first optical output branch or the second optical output branch according to the quantum communication coding control instruction.

[0079] In one embodiment of the present application, the first optical coupling unit 200 can select a connection to a corresponding optical output branch based on a quantum communication coding control instruction, and input an optical pulse of a time-phase-coded quantum state output by the time-phase coding unit 100 into the corresponding optical output branch. Specifically, when the quantum communication coding control instruction is an instruction corresponding to outputting a time-phase-coded quantum state, the first optical coupling unit 200 selects a connection to a second optical output branch and inputs an optical pulse of a time-phase-coded quantum state into the second optical output branch. When the quantum communication coding control instruction is an instruction corresponding to outputting a polarization-coded quantum state, the first optical coupling unit 200 selects a connection to a first optical output branch and inputs an optical pulse of a time-phase-coded quantum state into the first optical output branch, and then undergoes polarization coding conversion via the unequal-arm polarization control interferometer 300 to output an optical pulse of a polarization-coded quantum state.

[0080] In this embodiment, the second optical coupling unit 500 is an optical switch, which can connect the first optical output branch or the second optical output branch according to the quantum communication coding control instruction, that is, connect the first optical output branch that outputs the polarization-encoded quantum state optical pulse, or connect the second optical output branch that outputs the time phase-encoded quantum state optical pulse.

[0081] It should be noted that, generally, the optical output branch selected by the second optical coupling unit 500 for connection is consistent with the optical output branch selected by the first optical coupling unit 200 for connection. For example, the first optical coupling unit 200 and the second optical coupling unit 500 select the same optical output branch for connection based on the quantum communication coding control instruction. That is, the first optical coupling unit 200 selects the first optical output branch for connection based on the quantum communication coding control instruction, and the second optical coupling unit 500 also selects the first optical output branch for connection based on the quantum communication coding control instruction. When both the first optical coupling unit 200 and the second optical coupling unit 500 are connected to the first optical output branch, the second optical coupling unit 500 outputs an optical pulse in the polarization-encoded quantum state output by the first optical output branch. Correspondingly, when both the first optical coupling unit 200 and the second optical coupling unit 500 are connected to the second optical output branch, the second optical coupling unit 500 outputs an optical pulse in the time-phase-encoded quantum state output by the second optical output branch.

[0082] In the above embodiment, the first optical coupling unit 200 and the second optical coupling unit 500 can be connected to the same optical output branch according to quantum communication coding control instructions. This allows the output of quantum states required for encoding in the quantum communication system, thereby improving the flexibility and adaptability of the quantum communication system. Furthermore, the advantages of both coding methods can be fully utilized to ensure the adaptability of quantum states to the communication channel during quantum communication, thereby enhancing the security and reliability of the quantum communication system. Furthermore, this facilitates the integration of new coding methods, thereby supporting new communication protocols and higher-performance quantum state transmission.

[0083] In some embodiments, the first optical coupling unit 200 is an optical switch, and the second optical coupling unit 500 is an optical coupler.

[0084] In the embodiment of the present application, the first optical coupling unit 200 can freely switch the connection port based on the quantum communication coding control instruction, so as to be connected to the first optical output branch or the second optical output branch.

[0085] The optical coupler corresponding to the second optical coupling unit 500 may include two input ports and one output port, each of which may be connected to a corresponding optical output branch. The optical coupler is configured to output the optical pulses in the time-phase-encoded quantum state transmitted by the second optical output branch or the optical pulses in the polarization-encoded quantum state output by the first optical output branch.

[0086] Specifically, when the first optical coupling unit 200 is connected to the first optical output branch through the third port C based on the quantum communication coding control instruction, the first optical coupling unit 200 inputs the optical pulse of the time phase coded quantum state output by the time phase coding unit 100 into the first optical output branch through the third port C. At this time, the first optical output branch inputs the optical pulse of the time phase coded quantum state transmitted by the first optical coupling unit 200, and after conversion by the unequal-arm polarization control interferometer 300, outputs the optical pulse of the polarization coded quantum state. The input and output of the second optical output branch are both empty. The second optical coupling unit 500 couples the outputs of the two optical output branches, and the output coupling amount is the optical pulse of the polarization coded quantum state of the first optical output branch.

[0087] When the first optical coupling unit 200 is connected to the second optical output branch via the second port B based on the quantum communication coded control instruction, the first optical coupling unit 200 inputs the optical pulse of the time phase-encoded quantum state output by the time phase encoding unit 100 into the second optical output branch via the second port B. At this time, the second optical output branch receives the optical pulse of the time phase-encoded quantum state input by the first optical coupling unit 200 and outputs it, and the input and output of the first optical output branch are both empty. The second optical coupling unit 500 couples the outputs of the two optical output branches, and the output coupling amount is the optical pulse of the time phase-encoded quantum state of the second optical output branch.

[0088] In the above embodiment, the first optical coupling unit 200 can input an optical pulse of a time-phase-encoded quantum state into the optical output branch that matches the encoding required by the quantum communication system. The second optical coupling unit 500 can then output the quantum state required by the quantum communication system. This improves the flexibility and adaptability of the quantum communication system. Furthermore, the advantages of both encoding schemes can be fully utilized, ensuring the adaptability of quantum states to the communication channel during quantum communication, thereby improving the security and reliability of the quantum communication system. Furthermore, it facilitates the integration of new encoding schemes, thereby supporting new communication protocols and higher-performance quantum state transmission.

[0089] In one embodiment of the present application, refer to the attached Figure 3 The figure shows the second embodiment of the quantum state encoding device of the present application. In this embodiment, the unequal-arm polarization control interferometer 300 includes a third optical coupling unit 31, a fourth optical coupling unit 32, a second transmission optical path 33, and a third transmission optical path 34. The third optical coupling unit 31 includes at least three ports, including at least one input port and two output ports, namely, one input port D and two output ports E and port F. The fourth optical coupling unit 32 includes at least three ports, including two input ports and at least one output port, namely, two input ports E', port F', and one output port D'. The output port F of the third optical coupling unit 31 is connected to the input port F' of the fourth optical coupling unit 32 through the second transmission optical path 33, and the output port E of the third optical coupling unit 31 is connected to the input port E' of the fourth optical coupling unit 32 through the third transmission optical path 34. Among them, the input port D of the third optical coupling unit 31 is the input port of the unequal-arm polarization control interferometer 300, which is connected to the third port C of the first optical coupling unit 200. The output port D' of the fourth optical coupling unit 32 is the output port of the unequal-arm polarization control interferometer 300, which is connected to the fifth port C' of the second optical coupling unit 500. The optical path lengths of the second transmission optical path 33 and the third transmission optical path 34 are not equal. In the above embodiment, the third optical coupling unit 31 is used to split an input optical pulse into two optical sub-pulses, namely a first optical pulse and a second optical pulse. The first optical pulse and the second optical pulse are transmitted along the second transmission optical path 33 and the third transmission optical path 34, respectively, and are combined and output by the fourth optical coupling unit 32.

[0090] Refer to the attached Figure 4 Shown is the architecture diagram of the third embodiment of the quantum state encoding device of the present application. In this embodiment, the third optical coupling unit 31 and the fourth optical coupling unit 32 included in the unequal-arm polarization control interferometer 300 are the same optical coupling unit 41, and the unequal-arm polarization control interferometer 300 also includes a second transmission optical path 42, a third transmission optical path 43, and two reflectors 44 and 45.

[0091] The optical coupling unit 41 includes four ports, namely port D, port E, port F and port D', where port D is an input port, which is connected to the third port C of the first optical coupling unit 200, and port D' is an output port, which is connected to the fifth port C' of the second optical coupling unit 500. Port F and port E are connected to two reflectors 44 and 45 through the second transmission optical path 42 and the third transmission optical path 43, respectively. The reflectors 44 and 45 are used to reflect the input sub-light pulses back to the optical coupling unit 41.

[0092] like Figure 5 is a structural diagram of a first embodiment of an unequal-arm polarization control interferometer 300. In this embodiment, the third optical coupling unit 31 and the fourth optical coupling unit 32 are the same optical coupler. The second transmission optical path 33 and the third transmission optical path 34 are two different transmission optical paths. The unequal-arm polarization control interferometer 300 includes an optical coupler 51 (i.e., the third optical coupling unit 31 and the fourth optical coupling unit 32), a second transmission optical path 52 and a third transmission optical path 53, a reflector 54, and a reflector 55. An output port F of the optical coupler 51 is connected to one end of the second transmission optical path 52, another output port E of the optical coupler 51 is connected to one end of the third transmission optical path 53, the reflector 54 is connected to the other end of the second transmission optical path 52, and the reflector 55 is connected to the other end of the third transmission optical path 53. The reflectors 54 and 55 are used to reflect the input sub-light pulse back to the optical coupler 51. Optionally, one of the reflectors 54 and 55 is a 90° polarization state rotation mirror. In an exemplary embodiment, the 90° polarization state rotation mirror can be a quarter-wave plate mirror or a 90° Faraday rotation mirror, so that the polarization state of the reflected sub-light pulse is rotated 90° relative to the sub-light pulse input to the corresponding mirror, so that the polarization states of the two sub-light pulses are orthogonal to each other when they are reflected back to the optical coupler 51.

[0093] In this embodiment, the optical coupler 51 may include at least three ports, including at least one input port and two output ports, namely port D, port E, and port F. Port F and port E are connected to two reflectors via a second transmission optical path 52 and a third transmission optical path 53, respectively. Port D serves as an input port for receiving input optical pulses. Port E is connected to a reflector 55 via a third transmission optical path 53, and port F is connected to a reflector 54 via a second transmission optical path 52. When the optical coupler 51 includes three ports, the input port D can also serve as the output port of the unequal-arm polarization control interferometer 300, for outputting optical pulses of polarization-encoded quantum states; at this time, the unequal-arm polarization control interferometer 300 also includes an optical circulator (not shown in the figure), which is arranged at the front end of port D. The optical circulator includes three ports, namely a first port, a second port and a third port. The first port of the optical circulator is the input port of the unequal-arm polarization control interferometer 300, and the third port of the optical circulator is the output port of the unequal-arm polarization control interferometer 300. The second port of the optical circulator is connected to port D, and the optical pulse input by the first port of the optical circulator is output through the second port of the optical circulator, and the optical pulse input by the second port of the optical circulator is output through the third port of the optical circulator. When the optical coupler 51 includes four ports, the optical coupler 51 can also include an output port, such as Figure 5 The port D′ in the figure serves as the output port of the unequal-arm polarization control interferometer 300 for outputting optical pulses of polarization-encoded quantum states.

[0094] Refer to the attached Figure 6 The figure shows the structure of the second embodiment of the unequal-arm polarization control interferometer 300 of the present application. In this embodiment, the third optical coupling unit 31 and the fourth optical coupling unit 32 are the same polarization beam splitter. The second transmission optical path 33 and the third transmission optical path 34 are two different transmission optical paths. Figure 6 As shown in , the unequal-arm polarization control interferometer 300 of this embodiment includes a polarization beam splitter 61 (i.e., the third optical coupling unit 31 and the fourth optical coupling unit 32), a second transmission optical path 62 and a third transmission optical path 63, a reflector 64, and a reflector 65. The output port F of the polarization beam splitter 61 is connected to one end of the second transmission optical path 62, the output port E of the polarization beam splitter 61 is connected to one end of the third transmission optical path 63, the reflector 64 is connected to the other end of the second transmission optical path 62, and the reflector 65 is connected to the other end of the third transmission optical path 63. The reflector 64 and the reflector 65 are used to reflect the input sub-light pulse back to the polarization beam splitter 61. Optionally, the reflector 64 and the reflector 65 are polarization state rotation mirrors.

[0095] The polarization beam splitter 61 may include at least three ports, namely port D, port E and port F, wherein port F and port E are connected to two reflectors via the second transmission optical path 62 and the third transmission optical path 63, respectively. Port D serves as an input port for receiving input light pulses. Port E is connected to the reflector 65 via the third transmission optical path 63, and port F is connected to the reflector 64 via the second transmission optical path 62. When the polarization beam splitter 61 includes three ports, such as Figure 6 As shown in , the input port D can also serve as the output port of the unequal-arm polarization control interferometer 300, for outputting optical pulses of polarization-encoded quantum states; at this time, the unequal-arm polarization control interferometer 300 further includes an optical circulator (not shown in the figure), which is arranged at the front end of the port D. The optical circulator comprises three ports, namely a first port, a second port and a third port. The first port of the optical circulator is the input port of the unequal-arm polarization control interferometer 300, and the third port of the optical circulator is the output port of the unequal-arm polarization control interferometer 300. The second port of the optical circulator is connected to the port D, and the optical pulse input by the first port of the optical circulator is output via the second port of the optical circulator, and the optical pulse input by the second port of the optical circulator is output via the third port of the optical circulator.

[0096] When the polarization beam splitter 61 includes four ports, as shown in FIG. Figure 7 As shown in FIG, it is a structural diagram of the third embodiment of the unequal-arm polarization control interferometer 300 of the present application. The difference between this embodiment and the second embodiment is that the polarization beam splitter 61 can also include an output port, such as Figure 7 The port D′ in the figure serves as the output port of the unequal-arm polarization control interferometer 300 for outputting optical pulses of polarization-encoded quantum states.

[0097] It should be noted that, when the reflectors 64 and 65 do not rotate the polarization states of the input sub-light pulses, the polarization beam splitter 61 only outputs the combined light pulse in the polarization-encoded quantum state from port D. When the reflectors 64 and 65 rotate the polarization states of the input sub-light pulses by any angle (other than 0° and 90°), the polarization beam splitter 61 can output the combined light pulse in the polarization-encoded quantum state from port D or port D'. If the polarization states of the sub-light pulses are rotated by 90°, the combined light pulse in the polarization-encoded quantum state can only be output from port D'.

[0098] In this embodiment, the polarization beam splitter 61 is used to polarization-split a time-phase-encoded quantum state light pulse received from the input port into two sub-light pulses, and output them through port E and port F respectively, and transmit them along the second transmission optical path 62 and the third transmission optical path 63 to the two reflectors 64 and 65 respectively, and are reflected back to the polarization beam splitter 61 by the two reflectors 64 and 65.

[0099] like Figure 8 , which is a structural diagram of a fourth embodiment of an unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 is an optical coupler, and the fourth optical coupling unit 32 is a polarization combiner. The unequal-arm polarization control interferometer 300 includes an optical coupler 81, a second transmission optical path 82, a third transmission optical path 83, and a polarization combiner 84. The optical path lengths of the second transmission optical path 82 and the third transmission optical path 83 are unequal.

[0100] Based on this structure, in one embodiment, the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are orthogonal to each other, and the polarization states of the two time-slot sub-light pulses are the intrinsic polarization states of the polarization combiner 84, or there is an angle that is not 0 degrees with the intrinsic polarization state of the polarization combiner 84; or the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are the same, and there is an angle that is not 0 degrees with the intrinsic polarization state of the polarization combiner 84, preferably an angle of 45°.

[0101] In another embodiment, the second transmission optical path 82 or the third transmission optical path 83 is a 90° twisted polarization-maintaining optical fiber, or the unequal-arm polarization control interferometer 300 further includes: a 90° polarization state rotator 85 (e.g., Figure 8 ), a 90° polarization state rotator 85 is disposed on the second transmission optical path 82 or the third transmission optical path 83 to rotate the polarization state of the passing sub-light pulse by 90°. The 90° polarization state rotator 85 may be a half-wave plate or a 90° Faraday rotator. In this case, the polarization state of the two time-slot sub-light pulses input to the unequal-arm polarization control interferometer 300 is the same and is one of the intrinsic polarization states of the polarization combiner 84; or the polarization state of the two time-slot sub-light pulses input to the unequal-arm polarization control interferometer 300 is the same or orthogonal and is not the intrinsic polarization state of the polarization combiner 84.

[0102] In this embodiment, the optical coupler 81 may include three ports, namely, port D, port E, and port F. The polarization beam combiner 84 may include three ports, namely, port D', port E', and port F'. Port F of the optical coupler 81 may be connected to port F' of the polarization beam combiner 84 via a second transmission optical path 82, and port E of the optical coupler 81 may be connected to port E' of the polarization beam combiner 84 via a third transmission optical path 83.

[0103] Optical coupler 81 is used to split an optical pulse input from port D into two sub-optical pulses, namely a first optical pulse and a second optical pulse, which are output from ports F and E, respectively. The first optical pulse and the second optical pulse are transmitted along a second transmission optical path 82 and a third transmission optical path 83, respectively. The two sub-optical pulses are input to polarization beam combiner 84 from ports F' and E', respectively. Polarization beam combiner 84 is used to combine the two input sub-optical pulses and output an optical pulse with a polarization-encoded quantum state from port D'.

[0104] like Figure 9 , which is a structural diagram of a fifth embodiment of an unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 can be an optical coupler, and the fourth optical coupling unit 32 can be an optical coupler. The unequal-arm polarization control interferometer 300 includes: an optical coupler 91 (i.e., the third optical coupling unit 31), a second transmission optical path 92, a third transmission optical path 93, and an optical coupler 94 (i.e., the fourth optical coupling unit 32). The unequal-arm polarization control interferometer 300 further includes two polarizers, namely a polarizer 95 and a polarizer 96. The two polarizers 95 and 96 are respectively arranged on the second transmission optical path 92 and the third transmission optical path 93. One output port of the optical coupler 91 is connected to a first side port of the polarizer 95. The polarizer 95 is used to polarize one path of optical pulses output by the optical coupler 91. The other output port of the optical coupler 91 is connected to a first side port of the polarizer 96. The polarizer 96 is used to polarize the other path of optical pulses output by the optical coupler 91. The polarization directions of the two polarizers 95 and 96 are orthogonal to each other. The other side port of the polarizer 95 and the other side port of the polarizer 96 are respectively connected to the optical coupler 94 via the second transmission optical path 92 and the third transmission optical path 93. Optionally, the second transmission optical path 92 or the third transmission optical path 93 is a 90° twisted polarization-maintaining optical fiber, or the unequal-arm polarization control interferometer 300 further includes: a 90° polarization state rotator 97, which is arranged in the second transmission optical path 92 or the third transmission optical path 93, and is used to rotate the polarization state of the passing sub-light pulse by 90°. The 90° polarization state rotator 97 can be a half-wave plate or a 90° Faraday rotator.

[0105] like Figure 10 , which is a structural diagram of a sixth embodiment of an unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 can be a polarization beam splitter, and the fourth optical coupling unit 32 can be an optical coupler. The unequal-arm polarization control interferometer 300 includes a polarization beam splitter 1001 (i.e., the third optical coupling unit 31), a second transmission optical path 1002, a third transmission optical path 1003, and an optical coupler 1004 (i.e., the fourth optical coupling unit 32).

[0106] like Figure 10 As shown, the polarization beam splitter 1001 is connected to the optical coupler 1004 via the second transmission optical path 1002 and the third transmission optical path 1003. The polarization beam splitter 1001 may include three ports, namely, port D, port E, and port F. The optical coupler 1004 may include three ports, namely, port D', port E', and port F'. Port E of the polarization beam splitter 1001 may be connected to port E' of the optical coupler 1004 via the third transmission optical path 1003, and port F of the polarization beam splitter 1001 may be connected to port F' of the optical coupler 1004 via the second transmission optical path 1002.

[0107] In one embodiment, the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are orthogonal to each other, and the polarization states of the two time-slot sub-light pulses are the intrinsic polarization states of the polarization beam splitter 1001, or are at an angle other than 0 degrees with the intrinsic polarization state of the polarization beam splitter 1001; or the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are the same, and are at an angle other than 0 degrees with the intrinsic polarization state of the polarization beam splitter 1001, preferably an angle of 45°.

[0108] like Figure 11 , which is a structural diagram of a seventh embodiment of an unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 may be a polarization beam splitter, and the fourth optical coupling unit 32 may be a polarization beam combiner. In this embodiment, the unequal-arm polarization control interferometer 300 includes a polarization beam splitter 1101 (i.e., the third optical coupling unit 31), a second transmission optical path 1102, a third transmission optical path 1103, and a polarization beam combiner 1104 (i.e., the fourth optical coupling unit 32).

[0109] In one embodiment, the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are orthogonal to each other, and the polarization states of the two time-slot sub-light pulses are the intrinsic polarization states of the polarization beam splitter 1101, or are at an angle other than 0 degrees with the intrinsic polarization state of the polarization combiner 1104; or the polarization states of the two time-slot sub-light pulses input into the unequal-arm polarization control interferometer 300 are the same, and are at an angle other than 0 degrees with the intrinsic polarization state of the polarization combiner 1104, preferably an angle of 45°.

[0110] like Figure 11As shown, the polarization beam splitter 1101 is connected to the polarization beam combiner 1104 through the second transmission optical path 1102 and the third transmission optical path 1103. The polarization beam splitter 1101 may include three ports, namely port D, port E, and port F, and the polarization beam combiner 1104 may include three ports, namely port D', port E', and port F'. Port E of the polarization beam splitter 1101 may be connected to port E' of the polarization beam combiner 1104 through the third transmission optical path 1103, and port F of the polarization beam splitter 1101 may be connected to port F' of the polarization beam combiner 1104 through the second transmission optical path 1102. Port D of the polarization beam splitter 1101 serves as the input port of the unequal-arm polarization control interferometer 300, and port D' of the polarization beam combiner 1104 serves as the output port of the unequal-arm polarization control interferometer 300.

[0111] like Figure 12 , which is a structural diagram of an eighth embodiment of an unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 and the fourth optical coupling unit 32 are the same optical coupler. The unequal-arm polarization control interferometer 300 includes an optical coupler 1201, a second optical transmission path 1202, a third optical transmission path 1203, two reflectors 1204 and 1205, and two polarizers 1206 and 1207. The two output ports of the optical coupler 1201 are connected to one end of the second optical transmission path 1202 and one end of the third optical transmission path 1203, respectively. The two reflectors 1204 and 1205 are connected to the other end of the second optical transmission path 1202 and the other end of the third optical transmission path 1203, respectively. Two polarizers 1206 and 1207 are disposed on the second optical transmission path 1202 and the third optical transmission path 1203, respectively. The polarization directions of the two polarizers 1206 and 1207 are orthogonal to each other.

[0112] like Figure 13, which is a structural diagram of a ninth embodiment of the unequal-arm polarization control interferometer 300 according to an embodiment of the present application. In this embodiment, the third optical coupling unit 31 and the fourth optical coupling unit 32 are both optical couplers. The unequal-arm polarization control interferometer 300 includes: an optical coupler 1301, a second transmission optical path 1302, a third transmission optical path 1303, and an optical coupler 1304. The two output ports of the optical coupler 1301 are connected to the optical coupler 1304 via the second transmission optical path 1302 and the third transmission optical path 1303, respectively. In one embodiment, the polarization states of the two time-slot sub-light pulses input to the unequal-arm polarization control interferometer 300 are orthogonal to each other. In another embodiment, the second transmission optical path 1302 or the third transmission optical path 1303 is a 90° twisted polarization-maintaining fiber, or the unequal-arm polarization control interferometer 300 further includes a 90° polarization state rotator 1305. The 90° polarization state rotator 1305 is disposed on the second transmission optical path 1302 or the third transmission optical path 1303 and is configured to rotate the polarization state of the passing sub-light pulse by 90°. The 90° polarization state rotator 1305 may be a half-wave plate or a 90° Faraday rotator. In this case, the polarization states of the sub-light pulses in the two time slots input to the unequal-arm polarization control interferometer 300 are the same.

[0113] In some embodiments, according to the requirements of quantum communication, the quantum state encoding device of the present application can also be used in the quantum state decoding process.

[0114] According to the present application, a quantum state encoding method is provided, which uses the above-mentioned quantum state encoding device to implement time phase encoding.

[0115] The present application also provides a software-defined quantum communication system. Figure 14 As shown, it includes the above-mentioned quantum state encoding device 1401 and the encoding control device 1402. The encoding control device 1402 is used to generate quantum communication encoding control instructions based on the encoding requirements of the quantum communication system and send them to the quantum state encoding device 1401, so that the quantum state encoding device 1401 can select to output polarization-encoded quantum state light pulses or time phase-encoded quantum state light pulses based on the quantum communication encoding control instructions.

[0116] The quantum communication system can be a discrete variable quantum communication system or a continuous variable quantum communication system.

[0117] It should be understood that the specific features, operations, and details described hereinabove with respect to the apparatus of the present application may also be similarly applied to the method and system of the present application, or vice versa.

[0118] The various technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification as long as such combination does not conflict.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A quantum state encoding device, characterized in that: include: A time phase encoding unit, a first optical coupling unit, an unequal-arm polarization control interferometer, a first transmission optical path, and a second optical coupling unit; The temporal phase encoding unit comprises at least one input port and an output port, wherein the temporal phase encoding unit is configured to input an optical pulse through the input port, generate an optical pulse of a temporal phase encoded quantum state based on the optical pulse, and output the optical pulse through the output port; The first optical coupling unit comprises an input port and two output ports, namely a first port, a second port and a third port, wherein the first port is connected to the output port of the time phase encoding unit; The second optical coupling unit comprises two input ports and one output port, namely a fourth port, a fifth port and a sixth port; The unequal-arm polarization control interferometer includes an input port and an output port, which is used to perform polarization coding conversion on an input light pulse in a time-phase-coded quantum state and output a light pulse in a polarization-coded quantum state; The third port of the first optical coupling unit is connected to the input port of the unequal-arm polarization control interferometer, and the output port of the unequal-arm polarization control interferometer is connected to the fifth port of the second optical coupling unit to form a first optical output branch; The second port of the first optical coupling unit is connected to the fourth port of the second optical coupling unit through the first transmission optical path to form a second optical output branch; The first optical coupling unit is configured to input the optical pulse of the time phase coded quantum state output by the time phase coding unit into the first optical output branch and / or the second optical output branch according to a quantum communication coding control instruction, wherein the quantum communication coding control instruction is determined according to the coding requirements of the quantum communication system; The sixth port of the second optical coupling unit is the output port of the quantum state encoding device, which is used to output the time phase encoded quantum state optical pulse transmitted by the second optical output branch or the polarization encoded quantum state optical pulse output by the first optical output branch according to the quantum communication coding control instruction.

2. The device according to claim 1, characterized in that The first optical coupling unit is an optical coupler, and the second optical coupling unit is an optical switch.

3. The device according to claim 2, characterized in that The first optical coupling unit is configured to input the optical pulse of the time phase coded quantum state output by the time phase encoding unit through the first port, split the optical pulse of the time phase coded quantum state into two sub-optical pulses, and input the two sub-optical pulses into the first optical output branch and the second optical output branch through the third port and the second port, respectively; The second optical coupling unit is used to select, according to the quantum communication coding control instruction, to output the optical pulse of the time phase coded quantum state transmitted by the second optical output branch or the optical pulse of the polarization coded quantum state output by the first optical output branch.

4. The device according to claim 1, characterized in that The first optical coupling unit is an optical switch, and the second optical coupling unit is an optical switch or an optical coupler.

5. The device according to claim 4, characterized in that The first optical coupling unit is used to selectively input the optical pulse of the time phase coded quantum state into the first optical output branch or the second optical output branch according to the quantum communication coding control instruction; When the second optical coupling unit is optically switched, the second optical coupling unit is configured to connect the first optical output branch for outputting the optical pulse of the polarization-encoded quantum state or the second optical output branch for outputting the optical pulse of the time-phase-encoded quantum state according to the quantum communication coding control instruction; When the second optical coupling unit is an optical coupler, the second optical coupling unit is used to output the optical pulse in the polarization-encoded quantum state output by the first optical output branch or the optical pulse in the time-phase-encoded quantum state transmitted by the second optical output branch.

6. The device according to claim 1, characterized in that The unequal-arm polarization control interferometer comprises: a third optical coupling unit, a fourth optical coupling unit, a second transmission optical path and a third transmission optical path. The third optical coupling unit includes at least three ports, one input port and two output ports; the fourth optical coupling unit includes at least three ports, two input ports and one output port; the two output ports of the third optical coupling unit are connected to the two input ports of the fourth optical coupling unit through the second transmission optical path and the third transmission optical path; the input port of the third optical coupling unit is the input port of the unequal-arm polarization control interferometer, and the output port of the fourth optical coupling unit is the output port of the unequal-arm polarization control interferometer; the optical path lengths of the second transmission optical path and the third transmission optical path are not equal.

7. The device according to claim 6, characterized in that The third optical coupling unit and the fourth optical coupling unit are the same optical coupler, and the unequal-arm polarization control interferometer further includes: two reflecting mirrors, The two output ports of the optical coupler are respectively connected to one end of the second transmission optical path and one end of the third transmission optical path, and the two reflectors are respectively connected to the other end of the second transmission optical path and the other end of the third transmission optical path.

8. The device according to claim 7, characterized in that One of the two reflectors is a 90° polarization rotation reflector.

9. The device according to claim 6, characterized in that The third optical coupling unit and the fourth optical coupling unit are the same polarization beam splitter, and the unequal-arm polarization control interferometer further includes: two reflecting mirrors, The two output ports of the polarization beam splitter are respectively connected to one end of the second transmission light path and one end of the third transmission light path, and the two reflectors are respectively connected to the other end of the second transmission light path and the other end of the third transmission light path.

10. The device according to claim 9, characterized in that The two reflectors are both 90° polarization rotation reflectors.

11. The device according to claim 6, characterized in that The third optical coupling unit and the fourth optical coupling unit are the same optical coupler, and the unequal-arm polarization control interferometer further includes: two reflectors and two polarizers. The two output ports of the optical coupler are respectively connected to one end of the second transmission optical path and one end of the third transmission optical path, and the two reflectors are respectively connected to the other end of the second transmission optical path and the other end of the third transmission optical path; the two polarizers are respectively arranged on the second transmission optical path and the third transmission optical path, and the polarization directions of the two polarizers are orthogonal to each other.

12. The device according to claim 8 or 10, characterized in that The 90° polarization state rotation mirror is a quarter wave plate mirror or a 90° Faraday rotation mirror.

13. The device according to claim 6, characterized in that The third optical coupling unit is an optical coupler, and the fourth optical coupling unit is an optical coupler or a polarization combiner.

14. The device according to claim 13, characterized in that The second transmission optical path or the third transmission optical path is a 90° twisted polarization-maintaining optical fiber, or, The unequal-arm polarization control interferometer further includes a 90° polarization state rotator, which is arranged in the second transmission optical path or the third transmission optical path and is used to rotate the polarization state of the input sub-light pulse by 90°.

15. The device according to claim 6, characterized in that The third optical coupling unit is an optical coupler, the fourth optical coupling unit is an optical coupler, and the unequal-arm polarization control interferometer further includes: two polarizers, The two polarizers are respectively arranged on the second transmission light path and the third transmission light path, and the polarization directions of the two polarizers are orthogonal to each other.

16. The device according to claim 6, characterized in that The third optical coupling unit is a polarization beam splitter, and the fourth optical coupling unit is an optical coupler or a polarization beam combiner.

17. A quantum state encoding method, characterized in that: Quantum state encoding is achieved by applying the quantum state encoding device described in any one of claims 1 to 16.

18. A software-defined quantum communication system, characterized in that: A quantum state encoding device and encoding controller comprising any one of claims 1 to 16; The coding controller is used to generate quantum communication coding control instructions based on the coding requirements of the quantum communication system and send them to the quantum state coding device.

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