An integrated chip-based high-dimensional quantum key distribution system

Abstract

The present invention relates to an integrated chip high-dimensional quantum key distribution system, comprising a laser, a transmitting coding end chip, a receiving decoding end chip and a detector, wherein the laser is connected to the transmitting coding end chip, the transmitting coding end chip is connected to the receiving decoding end chip, and the receiving decoding end chip is connected to the detector. The transmitting coding end chip is integrated on the same photonic chip using silicon-based optical waveguides, and the receiving decoding end chip is integrated on the same photonic chip using silicon nitride. The present invention simultaneously integrates the transmitting coding end chip and the receiving decoding end chip in the time phase coding HD-QKD system. The transmitting coding end chip in the integrated system has a great advantage in coding rate, and the integrated receiving decoding end chip has very low insertion loss and good stability, which can realize the experimental demonstration and application of a stable, secure, high-speed modulation, and high-code rate HD-QKD protocol.

Description

Technical Field

[0001] The present invention relates to the field of quantum information technology, and in particular to an integrated chip-based high-dimensional quantum key distribution system. Background Art

[0002] With the rapid development of the information technology industry, secure information transmission is becoming increasingly important. The development of new technologies such as quantum computing will have a disruptive impact on traditional cryptographic systems. Furthermore, quantum communication, based on the fundamental principles of quantum mechanics, can theoretically achieve unconditional communication security. Currently, the most mature and widely developed technology in quantum communication is quantum key distribution (QKD), which primarily involves the preparation, transmission, and detection of quantum states.

[0003] To improve the key transmission efficiency of QKD, high-dimensional quantum key distribution (HD-QKD) has been proposed based on the traditional two-dimensional BB84 scheme. While traditional two-dimensional QKD carries one bit of key per photon, HD-QKD can enable each photon to carry multiple bits of key by expanding the Hilbert space dimension describing the quantum state. For example, a d-dimensional quantum state can carry log2 d bits of key per photon. In addition to its significant advantage in terms of information transmission, HD-QKD also has the potential to surpass the PLOB boundary, exhibit high channel noise resistance, and reduce cloning fidelity, making it a key development direction for future QKD. Currently, HD-QKD encoding methods include photon orbital angular momentum encoding, temporal phase encoding, path encoding, and temporal energy encoding. Temporal phase encoding is the most mature technology, with experimental demonstrations demonstrating secure key generation exceeding 10 Mbit / s under 40 km of optical fiber attenuation. Existing HD-QKD practical applications are relatively limited compared to traditional two-dimensional QKD, and are based on conventional fiber optic components. This approach is bulky, complex to debug, unstable, and expensive, making large-scale deployment difficult. With the recent development of integrated photonics, integrated, low-cost, low-power, and portable QKD systems will be a hot research topic in the future.

[0004] Therefore, based on the current development needs of HD-QKD, the present invention discloses an integrated HD-QKD system based on time phase coding, which includes a transmitter and a receiver, and can realize the experimental demonstration and application of the HD-QKD protocol.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides an integrated chip high-dimensional quantum key distribution system. The transmitting coding end chip in the integrated system has a great advantage in coding rate, and the integrated receiving decoding end chip has very small insertion loss and good stability. It can realize the experimental demonstration and application of the stable, secure, high-speed modulation and high-code rate HD-QKD protocol.

[0007] The integrated chip high-dimensional quantum key distribution system provided by the present invention includes a first laser, a second laser, a transmitting encoding end chip, a receiving decoding end chip, a photodetector, a first single-photon detector, a second single-photon detector, a third single-photon detector, a fourth single-photon detector, a fifth single-photon detector, a sixth single-photon detector, a seventh single-photon detector and an eighth single-photon detector;

[0008] The first laser and the second laser are both connected to the transmitting encoding end chip, the transmitting encoding end chip is connected to the receiving decoding end chip, and the receiving decoding end chip is respectively connected to the photodetector, the first single-photon detector, the second single-photon detector, the third single-photon detector, the fourth single-photon detector, the fifth single-photon detector, the sixth single-photon detector, the seventh single-photon detector, and the eighth single-photon detector;

[0009] The transmitting coding end chip includes a first fiber coupler, a second fiber coupler, a three-intensity joint modulation module, a phase modulation module, a multiplexing module, a third fiber coupler and a fourth fiber coupler;

[0010] The first optical fiber coupler is connected to the three-intensity joint modulation module, the three-intensity joint modulation module is connected to the phase modulation module, the phase modulation module is connected to the multiplexing module, and the multiplexing module is connected to the second optical fiber coupler, the third optical fiber coupler, and the fourth optical fiber coupler respectively.

[0011] The receiving and decoding end chip includes a fifth fiber coupler, a sixth fiber coupler, a seventh fiber coupler, an eighth fiber coupler, a ninth fiber coupler, a tenth fiber coupler, an eleventh fiber coupler, a twelfth fiber coupler, a thirteenth fiber coupler, a fourteenth fiber coupler, a fifteenth fiber coupler, a sixteenth fiber coupler, a seventeenth fiber coupler, an eighteenth fiber coupler, a nineteenth fiber coupler, a twentieth fiber coupler, a demultiplexer, a variable optical beam splitting module, a time-based decoding module, and a phase-based decoding module.

[0012] The fifth fiber coupler is connected to the demultiplexer, the demultiplexer is respectively connected to the ninth fiber coupler and the variable optical beam splitting module, the variable optical beam splitting module is respectively connected to the time-base decoding module and the phase-base decoding module, the time-base decoding module is respectively connected to the tenth fiber coupler, the eleventh fiber coupler, the twelfth fiber coupler, and the thirteenth fiber coupler, and the phase-base decoding module is respectively connected to the sixteenth fiber coupler, the seventeenth fiber coupler, the eighteenth fiber coupler, the nineteenth fiber coupler, and the twentieth fiber coupler.

[0013] The triple-intensity joint modulation module includes a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, and a sixth beam splitter;

[0014] Two optical arms are provided between the first beam splitter and the second beam splitter. A first thermally tuned phase shifter and a first carrier dispersion phase shifter are connected in series on the first optical arm, and a second thermally tuned phase shifter and a second carrier dispersion phase shifter are connected in series on the second optical arm. The first thermally tuned phase shifter and the second thermally tuned phase shifter are both connected to the first beam splitter, and the first carrier dispersion phase shifter and the second carrier dispersion phase shifter are both connected to the second beam splitter. A first optical power detector is also connected to the second beam splitter. The first beam splitter is connected to the first optical fiber coupler.

[0015] Two optical arms are provided between the third beam splitter and the fourth beam splitter. A third thermally tuned phase shifter and a third carrier dispersion phase shifter are connected in series on the first optical arm, and a fourth thermally tuned phase shifter and a fourth carrier dispersion phase shifter are connected in series on the second optical arm. The third thermally tuned phase shifter and the fourth thermally tuned phase shifter are both connected to the third beam splitter, and the third carrier dispersion phase shifter and the fourth carrier dispersion phase shifter are both connected to the fourth beam splitter. A second optical power detector is also connected to the fourth beam splitter. The second beam splitter is connected to the third beam splitter.

[0016] Two optical arms are provided between the fifth beam splitter and the sixth beam splitter. A fifth thermally tuned phase shifter and a fifth carrier dispersion phase shifter are connected in series on the first optical arm, and a sixth thermally tuned phase shifter and a sixth carrier dispersion phase shifter are connected in series on the second optical arm. The fifth thermally tuned phase shifter and the sixth thermally tuned phase shifter are both connected to the fifth beam splitter, and the fifth carrier dispersion phase shifter and the sixth carrier dispersion phase shifter are both connected to the sixth beam splitter. A third optical power detector is also connected to the sixth beam splitter. The fourth beam splitter is connected to the fifth beam splitter.

[0017] The phase modulation module includes a seventh beam splitter, an eighth beam splitter, a ninth beam splitter, a tenth beam splitter, an eleventh beam splitter, and a twelfth beam splitter;

[0018] Two optical arms are provided between the eighth beam splitter and the ninth beam splitter. A seventh thermally tuned phase shifter and a seventh carrier dispersion phase shifter are connected in series on the first optical arm, and an eighth thermally tuned phase shifter and an eighth carrier dispersion phase shifter are connected in series on the second optical arm. The seventh thermally tuned phase shifter and the eighth thermally tuned phase shifter are both connected to the eighth beam splitter, and the seventh carrier dispersion phase shifter and the eighth carrier dispersion phase shifter are both connected to the ninth beam splitter.

[0019] Two optical arms are provided between the tenth beam splitter and the eleventh beam splitter. A ninth thermally tuned phase shifter and a ninth carrier dispersion type phase shifter are connected in series on the first optical arm, and a tenth thermally tuned phase shifter and a tenth carrier dispersion type phase shifter are connected in series on the second optical arm. The ninth thermally tuned phase shifter and the tenth thermally tuned phase shifter are both connected to the tenth beam splitter, and the ninth carrier dispersion type phase shifter and the tenth carrier dispersion type phase shifter are both connected to the eleventh beam splitter.

[0020] The sixth beam splitter is connected to the seventh beam splitter, the seventh beam splitter is connected to the eighth beam splitter and the tenth beam splitter respectively, the ninth beam splitter is connected to the twelfth beam splitter, and the eleventh beam splitter is connected to the twelfth beam splitter via the eleventh thermally tuned phase shifter.

[0021] The multiplexing modules respectively include a thirteenth beam splitter, a variable optical attenuator, a fourth optical power detector, a multiplexer, a fourteenth beam splitter, and a fifth optical power detector;

[0022] The thirteenth beam splitter is respectively connected to the variable optical attenuator and the fourth optical power detector; the variable optical attenuator is connected to the twelfth beam splitter; the thirteenth beam splitter is also respectively connected to the third optical fiber coupler and the multiplexer; the multiplexer is respectively connected to the fourth optical fiber coupler and the fourteenth beam splitter; the fourteenth beam splitter is also respectively connected to the second optical fiber coupler and the fifth optical power detector.

[0023] The variable optical beam splitting module includes a fifteenth beam splitter and a sixteenth beam splitter, two optical arms are provided between the fifteenth beam splitter and the sixteenth beam splitter, and a twelfth thermally tunable phase shifter and a thirteenth thermally tunable phase shifter are provided on the two optical arms respectively; the fifteenth beam splitter is respectively connected to the demultiplexer and the sixth optical fiber coupler, and the sixteenth beam splitter is respectively connected to the time-based decoding module, the fourteenth optical fiber coupler, the fifteenth optical fiber coupler and the phase-based decoding module.

[0024] The time base decoding module includes a seventeenth beam splitter, an eighteenth beam splitter and a nineteenth beam splitter, the seventeenth beam splitter is connected to the eighteenth beam splitter and the nineteenth beam splitter respectively; the sixteenth beam splitter is connected to the seventeenth beam splitter, the eighteenth beam splitter is connected to the tenth fiber coupler and the eleventh fiber coupler respectively, and the nineteenth beam splitter is connected to the twelfth fiber coupler and the thirteenth fiber coupler respectively.

[0025] The phase-based decoding module adopts a cascaded tree interferometer structure, including a 20th beam splitter, a 21st beam splitter, a 22nd beam splitter, a 23rd beam splitter, a 24th beam splitter, a 25th beam splitter, a 26th beam splitter, a 27th beam splitter and a 28th beam splitter;

[0026] Two optical arms are provided between the second demultiplexer and the twenty-first beam splitter, a fourteenth thermally tuned phase shifter is provided on the first optical arm, and a fifteenth thermally tuned phase shifter is provided on the second optical arm; the sixteenth beam splitter is connected to the second demultiplexer; two optical arms are provided between the twenty-first beam splitter and the twenty-second beam splitter, a first delay line and a second delay line are connected in series on the first optical arm, and a sixteenth thermally tuned phase shifter is provided on the second optical arm; the first delay line is connected to the twenty-first beam splitter, and the second delay line is connected to the twenty-second beam splitter;

[0027] Two optical arms are provided between the twenty-third beam splitter and the twenty-fourth beam splitter, the first optical arm being provided with a seventeenth thermally tuned phase shifter, and the second optical arm being provided with an eighteenth thermally tuned phase shifter; the twenty-second beam splitter is connected to the twenty-third beam splitter, which is also connected to the sixteenth optical fiber coupler; two optical arms are provided between the twenty-fourth beam splitter and the twenty-fifth beam splitter, the first optical arm being provided with a third delay line, and the second optical arm being provided with a twenty-first thermally tuned phase shifter; the twenty-fifth beam splitter is connected to the seventeenth optical fiber coupler and the eighteenth optical fiber coupler, respectively;

[0028] Two optical arms are provided between the twenty-sixth beam splitter and the twenty-seventh beam splitter, the first optical arm is provided with a nineteenth thermally tuned phase shifter, and the second optical arm is provided with a twentieth thermally tuned phase shifter; the twenty-second beam splitter is connected to the twenty-sixth beam splitter, and the twenty-sixth beam splitter is also connected to the eighth optical fiber coupler; two optical arms are provided between the twenty-seventh beam splitter and the twenty-eighth beam splitter, the first optical arm is provided with a twenty-second thermally tuned phase shifter, and the second optical arm is provided with a fourth delay line; the twenty-eighth beam splitter is connected to the nineteenth optical fiber coupler and the 20th optical fiber coupler, respectively.

[0029] Preferably, the first laser is connected to the first fiber coupler via an optical fiber, the second laser is connected to the second fiber coupler via an optical fiber, the connections of the transmitting encoding end chip are all connected via a silicon-based optical waveguide, the connections of the receiving decoding end chip are all connected via a silicon nitride optical waveguide, the transmitting encoding end chip is connected to the receiving decoding end chip via an optical fiber, the ninth fiber coupler is connected to the photodetector via an optical fiber, the tenth fiber coupler is connected to the first single-photon detector via an optical fiber, the eleventh fiber coupler is connected to the second single-photon detector via an optical fiber, the twelfth fiber coupler is connected to the third single-photon detector via an optical fiber, the thirteenth fiber coupler is connected to the fourth single-photon detector via an optical fiber, the seventeenth fiber coupler is connected to the fifth single-photon detector via an optical fiber, the eighteenth fiber coupler is connected to the sixth single-photon detector via an optical fiber, the nineteenth fiber coupler is connected to the seventh single-photon detector via an optical fiber, and the twentieth fiber coupler is connected to the eighth single-photon detector via an optical fiber.

[0030] Beneficial effects of the present invention:

[0031] (1) The present invention can realize the experimental demonstration and application of a stable, secure, high-speed modulation, and high-bitrate HD-QKD protocol;

[0032] (2) The present invention implements the HD-QKD protocol, which is a breakthrough in the traditional two-dimensional quantum key distribution scheme. Compared with traditional QKD, it has outstanding advantages such as high information content, high system stability, and high noise resistance.

[0033] (3) The present invention uses IQ modulation to adjust the phase of the quantum state, ensuring that the intensity of the light pulse is basically consistent when adjusting different phases, greatly improving the fidelity of the quantum state preparation;

[0034] (4) The present invention implements a method for joint modulation of three intensity modulators on a chip. Each intensity modulator has its own specific function, so that no disturbance occurs between the modulated signals and the modulation speed can be maximized.

[0035] (5) The present invention integrates a wavelength division multiplexer and a de-wavelength division multiplexer on the chip to multiplex the signal light and the synchronization light, further improving the integration of the QKD chip while reducing the use of traditional wavelength division multiplexing devices, making the system more stable.

[0036] (6) The present invention is equipped with multiple optical power detectors, which are very convenient for judging whether the chip debugging meets the requirements, and can also play a role in monitoring the status of each module during use;

[0037] (7) The present invention uses a silicon nitride platform to integrate the receiving end, which can reduce the insertion loss of the receiving end chip and improve the detection efficiency of the receiving end;

[0038] (8) The present invention uses a variable optical beam splitter and a tunable Mach-Zehnder interferometer at the receiving end, which can achieve the required experimental indicators through external adjustment, thereby improving the tolerance of the system.

[0039] Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.

[0041] Figure 1 The figure shows the structure of the integrated chip high-dimensional quantum key distribution system provided by the present invention.

[0042] In the figure, 1-high-dimensional quantum key distribution transmitter, 11-transmitting encoding end, 12-first laser, 13-second laser, 1101-first fiber coupler, 1102-second fiber coupler, 1103-three-intensity joint modulation module, 1104-phase modulation module, 1105-multiplexing module, 1106-third fiber coupler, 1107-fourth fiber coupler, 110301-first beam splitter, 110302-second beam splitter, 110303-first thermally tunable phase shifter, 110304-first carrier dispersion phase shifter, 110305-second thermally tunable phase shifter, 110306-second carrier dispersion phase shifter, 110307-first optical power detector, 110 308-third beam splitter, 110309-fourth beam splitter, 110310-third thermally tuned phase shifter, 110311-third carrier dispersion phase shifter, 110312-fourth thermally tuned phase shifter, 110313-fourth carrier dispersion phase shifter, 110314-second optical power detector, 110315-fifth beam splitter, 110316-sixth beam splitter, 110317-fifth thermally tuned phase shifter, 110318-fifth carrier dispersion phase shifter, 110319-sixth thermally tuned phase shifter, 1103020-sixth carrier dispersion phase shifter, 1103021-third optical power detector, 110401-seventh beam splitter, 110402-eighth beam splitter Beam splitter, 110403-10th beam splitter, 110404-7th thermally tunable phase shifter, 110405-7th carrier dispersion phase shifter, 110406-8th thermally tunable phase shifter, 110407-8th carrier dispersion phase shifter, 110408-9th thermally tunable phase shifter, 110409-9th carrier dispersion phase shifter, 110410-10th thermally tunable phase shifter, 110411-10th carrier dispersion phase shifter, 110412-9th beam splitter, 110413-11th beam splitter, 110414-11th thermally tunable phase shifter, 110415-12th beam splitter, 110501-4th optical power detector, 110502-variable optical attenuator, 1 10503 - 13th beam splitter, 110504 - multiplexer, 110505 - 14th beam splitter, 110506 - 5th optical power detector, 2 - high-dimensional quantum key distribution receiving end, 21 - receiving and decoding end chip, 2101 - 5th fiber coupler, 2102 - demultiplexer, 2103 - variable optical beam splitting module, 2104 - time-based decoding module, 2105 - phase-based decoding module, 2106 - 9th fiber coupler, 2107 - 10th fiber coupler, 2108 - 11th fiber coupler, 2109 - 12th fiber coupler, 2110 - 13th fiber coupler, 2111 - 14th fiber coupler, 2112 - 15th fiber coupler, 2113 - 16th fiber coupler,2114-17th fiber coupler, 2115-18th fiber coupler, 2116-19th fiber coupler, 2117-20th fiber coupler, 2118-6th fiber coupler, 2119-7th fiber coupler, 2120-8th fiber coupler, 21031-15th beam splitter, 21032-12th thermally tuned phase shifter, 21033-13th thermally tuned phase shifter, 21034-16th beam splitter, 21041-17th Seventeenth beam splitter, 21042-Eighteenth beam splitter, 21043-Nineteenth beam splitter, 210501-Twenty-first beam splitter, 210502-Fourteenth thermally tuned phase shifter, 210503-Fifteenth thermally tuned phase shifter, 210504-Twenty-first beam splitter, 210505-First delay line, 210506-Second delay line, 210507-Sixteenth thermally tuned phase shifter, 210508-Twenty-second beam splitter, 210509- 23rd beam splitter, 210510-17th thermally tuned phase shifter, 210511-18th thermally tuned phase shifter, 210512-24th beam splitter, 210513-3rd delay line, 210514-21st thermally tuned phase shifter, 210515-25th beam splitter, 210516-26th beam splitter, 210517-19th thermally tuned phase shifter, 210518-20th thermally tuned phase shifter, 21051 9-27th beam splitter, 210520-22nd thermally tuned phase shifter, 210521-4th delay line, 210522-28th beam splitter, 22-photodetector, 23-1st single-photon detector, 24-2nd single-photon detector, 25-3rd single-photon detector, 26-4th single-photon detector, 27-5th single-photon detector, 28-6th single-photon detector, 29-7th single-photon detector, 210-8th single-photon detector. DETAILED DESCRIPTION

[0043] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise expressly stated, throughout the specification and claims, the term "including" or its variations such as "comprising" or "including" will be understood to include the stated elements or components, without excluding other elements or other components.

[0045] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0046] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention can be practiced without certain specific details. In some instances, methods, means, and components well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.

[0047] Example 1

[0048] Figure 1 The structure diagram of the integrated chip high-dimensional quantum key distribution system provided by the first embodiment of the present invention is shown as follows: Figure 1 As shown, the integrated chip high-dimensional quantum key distribution system of the present invention includes a transmitting end 1, a receiving end 2, a transmitting encoding end chip 11, a first laser 12, a second laser 13, a receiving decoding end chip 21, a photodetector 22, a first single-photon detector 23, a second single-photon detector 24, a third single-photon detector 25, a fourth single-photon detector 26, a fifth single-photon detector 27, a sixth single-photon detector 28, a seventh single-photon detector 29 and an eighth single-photon detector 210;

[0049] The first laser 12 and the second laser 13 are both connected to the transmitting coding end chip 11, the transmitting coding end chip 11 is connected to the receiving decoding end chip 21, and the receiving decoding end chip 21 is respectively connected to the photodetector 22, the first single-photon detector 23, the second single-photon detector 24, the third single-photon detector 25, the fourth single-photon detector 26, the fifth single-photon detector 27, the sixth single-photon detector 28, the seventh single-photon detector 29 and the eighth single-photon detector 210.

[0050] The transmitting coding end chip 11 includes a first fiber coupler 1101 , a second fiber coupler 1102 , a triple intensity joint modulation module 1103 , a phase modulation module 1104 , a multiplexing module 1105 , a third fiber coupler 1106 and a fourth fiber coupler 1107 .

[0051] The first optical fiber coupler 1101 is connected to the three-intensity joint modulation module 1103, the three-intensity joint modulation module 1103 is connected to the phase modulation module 1104, the phase modulation module 1104 is connected to the multiplexing module 1105, and the multiplexing module 1105 is connected to the second optical fiber coupler 1102, the third optical fiber coupler 1101 and the fourth optical fiber coupler 1107 respectively.

[0052] The receiving and decoding end chip 21 includes a fifth fiber coupler 2101, a sixth fiber coupler 2118, a seventh fiber coupler 2119, an eighth fiber coupler 2120, a ninth fiber coupler 2106, a tenth fiber coupler 2107, an eleventh fiber coupler 2108, a twelfth fiber coupler 2109, a thirteenth fiber coupler 2110, a fourteenth fiber coupler 2111, a fifteenth fiber coupler 2112, a sixteenth fiber coupler 2113, a seventeenth fiber coupler 2114, an eighteenth fiber coupler 2115, a nineteenth fiber coupler 2116, a twentieth fiber coupler 2117, a demultiplexer 2102, a variable optical beam splitting module 2103, a time-based decoding module 2104, and a phase-based decoding module 2105.

[0053] The fifth fiber coupler 2101 is connected to the demultiplexer 2102, the demultiplexer 2102 is respectively connected to the ninth fiber coupler 2106 and the variable optical beam splitting module 2103, the ninth fiber coupler 2106 is connected to the photodetector 22, and the variable optical beam splitting module 2103 is respectively connected to the time-base decoding module 2104 and the phase-base decoding module 2105; the time-base decoding module 2104 is respectively connected to the tenth fiber coupler 2107, the eleventh fiber coupler 2108, the twelfth fiber coupler 2109, and the thirteenth fiber coupler 2110; and the phase-base decoding module 2105 is respectively connected to the sixteenth fiber coupler 2113, the seventeenth fiber coupler 2114, the eighteenth fiber coupler 2115, the nineteenth fiber coupler 2116, and the twentieth fiber coupler 2117.

[0054] The triple-intensity joint modulation module 1103 includes a first beam splitter 110301 and a second beam splitter 110302. Two optical arms are provided between the first beam splitter 110301 and the second beam splitter 110302. A first thermally tuned phase shifter 110303 and a first carrier dispersion phase shifter 110304 are connected in series on the first optical arm. A second thermally tuned phase shifter 110305 and a second carrier dispersion phase shifter 110306 are connected in series on the second optical arm. 6; The first thermally tunable phase shifter 110303 and the second thermally tunable phase shifter 110305 are both connected to the first beam splitter 110301, and the first carrier dispersion phase shifter 110304 and the second carrier dispersion phase shifter 110306 are both connected to the second beam splitter 110302; the first optical power detector 110307 is also connected to the second beam splitter 110302; the first beam splitter 110301 is connected to the first optical fiber coupler 1101.

[0055] Two optical arms are provided between the third beam splitter 110308 and the fourth beam splitter 110309. A third thermally tuned phase shifter 110310 and a third carrier dispersion type phase shifter 110311 are connected in series on the first optical arm, and a fourth thermally tuned phase shifter 110312 and a fourth carrier dispersion type phase shifter 110313 are connected in series on the second optical arm. The third thermally tuned phase shifter 110310 and the fourth thermally tuned phase shifter 110312 are both connected to the third beam splitter 110308, and the third carrier dispersion type phase shifter 110311 and the fourth carrier dispersion type phase shifter 110313 are both connected to the fourth beam splitter 110309. A second optical power detector 110314 is also connected to the fourth beam splitter 110309. The second beam splitter 110302 is connected to the third beam splitter 110308.

[0056] Two optical arms are provided between the fifth beam splitter 110315 and the sixth beam splitter 110316. The fifth thermally tuned phase shifter 110317 and the fifth carrier dispersion phase shifter 110318 are connected in series on the first optical arm, and the sixth thermally tuned phase shifter 110319 and the sixth carrier dispersion phase shifter 110320 are connected in series on the second optical arm; the fifth thermally tuned phase shifter 110317 and the sixth thermally tuned phase shifter 110319 are both connected to the fifth beam splitter 110315, and the fifth carrier dispersion phase shifter 110318 and the sixth carrier dispersion phase shifter 110320 are both connected to the sixth beam splitter 110316; the third optical power detector 110321 is also connected to the sixth beam splitter 110316; the fourth beam splitter 110309 is connected to the fifth beam splitter 110315.

[0057] The phase modulation module 1104 includes a seventh beam splitter 110401 , an eighth beam splitter 110402 , a ninth beam splitter 110412 , a tenth beam splitter 110403 , an eleventh beam splitter 110413 , and a twelfth beam splitter 110415 .

[0058] Two optical arms are provided between the eighth beam splitter 110402 and the ninth beam splitter 110412. The seventh thermally tuned phase shifter 110404 and the seventh carrier dispersion type phase shifter 110405 are connected in series on the first optical arm, and the eighth thermally tuned phase shifter 110406 ​​and the eighth carrier dispersion type phase shifter 110407 are connected in series on the second optical arm; the seventh thermally tuned phase shifter 110404 and the eighth thermally tuned phase shifter 110406 ​​are both connected to the eighth beam splitter 110402, and the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 are both connected to the ninth beam splitter 110412.

[0059] Two optical arms are provided between the tenth beam splitter 110403 and the eleventh beam splitter 110413. The ninth thermally tuned phase shifter 110408 and the ninth carrier dispersion type phase shifter 110409 are connected in series on the first optical arm, and the tenth thermally tuned phase shifter 110410 and the tenth carrier dispersion type phase shifter 110411 are connected in series on the second optical arm. The ninth thermally tuned phase shifter 110408 and the tenth thermally tuned phase shifter 110410 are both connected to the tenth beam splitter 110403, and the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411 are both connected to the eleventh beam splitter 110413.

[0060] The sixth beam splitter 110316 is connected to the seventh beam splitter 110401, the seventh beam splitter 110401 is respectively connected to the eighth beam splitter 110402 and the tenth beam splitter 110403, the ninth beam splitter 110412 is connected to the twelfth beam splitter 110415, and the eleventh beam splitter 110413 is connected to the twelfth beam splitter 110415 via the eleventh thermally tuned phase shifter 110414.

[0061] The multiplexing module 1105 includes a tenth beam splitter 110503, a variable optical attenuator 110502, a fourth optical power detector 110501, a multiplexer 110504, a fourteenth beam splitter 110505, and a fifth optical power detector 110506;

[0062] The tenth de-beam splitter 110503 is respectively connected to the variable optical attenuator 110502 and the fourth optical power detector 110501; the variable optical attenuator 110502 is connected to the twelfth beam splitter 110415; the tenth de-beam splitter 110503 is also respectively connected to the third optical fiber coupler 1106 and the multiplexer 110504; the multiplexer 110504 is respectively connected to the fourth optical fiber coupler 1107 and the fourteenth beam splitter 110505; the fourteenth beam splitter 110505 is also respectively connected to the second optical fiber coupler 1102 and the fifth optical power detector 110506.

[0063] The variable optical beam splitting module 2103 includes a fifteenth beam splitter 21031 and a sixteenth beam splitter 21034. Two optical arms are provided between the fifteenth beam splitter 21031 and the sixteenth beam splitter 21034, and a twelfth thermally tunable phase shifter 21032 and a thirteenth thermally tunable phase shifter 21033 are provided on these two optical arms respectively; the fifteenth beam splitter 21031 is respectively connected to the demultiplexer 2102 and the sixth optical fiber coupler 2118, and the sixteenth beam splitter 21034 is respectively connected to the time base decoding module 2104, the fourteenth optical fiber coupler 2111, the fifteenth optical fiber coupler 2112 and the phase base decoding module 2105.

[0064] The time base decoding module 2104 includes a seventeenth beam splitter 21041, an eighteenth beam splitter 21042 and a nineteenth beam splitter 21043. The seventeenth beam splitter 21041 is connected to the eighteenth beam splitter 21042 and the nineteenth beam splitter 21043 respectively; the sixteenth beam splitter 21034 is connected to the seventeenth beam splitter 21041, the eighteenth beam splitter 21042 is connected to the tenth fiber coupler 2107 and the eleventh fiber coupler 2108 respectively, and the nineteenth beam splitter 21043 is connected to the twelfth fiber coupler 2109 and the thirteenth fiber coupler 2110 respectively; the tenth fiber coupler 2107 is connected to the first single-photon detector 23, the eleventh fiber coupler 2108 is connected to the second single-photon detector 24, the twelfth fiber coupler 2109 is connected to the third single-photon detector 25, and the thirteenth fiber coupler 2110 is connected to the fourth single-photon detector 26.

[0065] The phase-based decoding module 2105 adopts a cascaded tree interferometer structure, including a 20th beam splitter 210501, a 21st beam splitter 210504, a 22nd beam splitter 210508, a 23rd beam splitter 210509, a 24th beam splitter 210512, a 25th beam splitter 210515, a 26th beam splitter 210516, a 27th beam splitter 210519, and a 28th beam splitter 210522.

[0066] Two optical arms are provided between the 2nd demultiplexer 210501 and the 21st beam splitter 210504, the first optical arm being provided with a 14th thermally tuned phase shifter 210502, and the second optical arm being provided with a 15th thermally tuned phase shifter 210503; the 16th beam splitter 210507 is connected to the 20th demultiplexer 210501; two optical arms are provided between the 21st beam splitter 210504 and the 22nd beam splitter 210508, the first optical arm being provided with a first delay line 210505 and a second delay line 210506 connected in series, and the second optical arm being provided with a 16th thermally tuned phase shifter 210507; the first delay line 210505 is connected to the 21st beam splitter 210504, and the second delay line 210506 is connected to the 22nd beam splitter 210518;

[0067] Two optical arms are provided between the twenty-third beam splitter 210521 and the twenty-fourth beam splitter 210512. The first optical arm is provided with a seventeenth thermally tuned phase shifter 210510, and the second optical arm is provided with an eighteenth thermally tuned phase shifter 210511. The twenty-second beam splitter 210508 is connected to the twenty-third beam splitter 210509, which is further connected to the sixteenth fiber coupler 2113. Two optical arms are provided between the twenty-fourth beam splitter 210512 and the twenty-fifth beam splitter 210515. The first optical arm is provided with a third delay line 210513, and the second optical arm is provided with a twenty-first thermally tuned phase shifter 210514. The twenty-fifth beam splitter 210515 is respectively connected to the seventeenth fiber coupler 2114 and the eighteenth fiber coupler 2115.

[0068] Two optical arms are provided between the twenty-sixth beam splitter 210516 and the twenty-seventh beam splitter 210519, the first optical arm is provided with a nineteenth thermally tuned phase shifter 210517, and the second optical arm is provided with a twentieth thermally tuned phase shifter 210518; the twenty-second beam splitter 210508 is connected to the twenty-sixth beam splitter 210516, and the twenty-sixth beam splitter 210516 is also connected to the eighth optical fiber coupler 2120; two optical arms are provided between the twenty-seventh beam splitter 210519 and the twenty-eighth beam splitter 210522, the first optical arm is provided with a twenty-second thermally tuned phase shifter 210520, and the second optical arm is provided with a fourth delay line 210521; the twenty-eighth beam splitter 210522 is respectively connected to the nineteenth optical fiber coupler 2116 and the twentieth optical fiber coupler 2117.

[0069] In this embodiment, the first laser 12 is connected to the first fiber coupler 1101 via an optical fiber, the second laser 13 is connected to the second fiber coupler 1102 via an optical fiber, the connection between the transmitting encoding end chip 11 is connected via a silicon-based optical waveguide, the connection between the receiving decoding end chip 21 is connected via a silicon nitride optical waveguide, the transmitting end 1 is connected to the receiving end 2 via an optical fiber, the ninth fiber coupler 2106 is connected to the photodetector 22 via an optical fiber, the tenth fiber coupler 2107 is connected to the first single-photon detector 23 via an optical fiber, and the eleventh fiber coupler 2108 is connected to the second single-photon detector 24 via an optical fiber. The sub-detector 24 is connected via optical fiber, the twelfth optical fiber coupler 2109 is connected to the third single-photon detector 25 via optical fiber, the thirteenth optical fiber coupler 2110 is connected to the fourth single-photon detector 26 via optical fiber, the seventeenth optical fiber coupler 2114 is connected to the fifth single-photon detector 27 via optical fiber, the eighteenth optical fiber coupler 2115 is connected to the sixth single-photon detector 28 via optical fiber, the nineteenth optical fiber coupler 2116 is connected to the seventh single-photon detector 29 via optical fiber, and the twentieth optical fiber coupler 2117 is connected to the eighth single-photon detector 210 via optical fiber.

[0070] The integrated chip-based high-dimensional quantum key distribution system provided in this embodiment integrates both the transmitting encoding module and the receiving decoding module, and can implement the time phase coding-based HD-QKD protocol shown in Example 2.

[0071] Example 2: Implementation of an integrated HD-QKD system based on time phase encoding

[0072] Step S1: Continuous light emitted by an off-chip laser is coupled into a waveguide via the first fiber coupler 1101 and enters the transmitting encoding end chip 11. The first thermally tuned phase shifter 110303 is adjusted to maximize the output light intensity of the first optical power detector 110307. The third thermally tuned phase shifter 110301 is adjusted to maximize the output light intensity of the second optical power detector 110314. The fifth thermally tuned phase shifter 110317 is adjusted to maximize the output light intensity of the third optical power detector 110321. The seventh thermally tuned phase shifter 110404 and the ninth thermally tuned phase shifter 110408 are adjusted to maximize the output light intensity of the off-chip photodetector connected to the third fiber coupler 1111, thereby balancing the initial phase difference caused by manufacturing process errors. Then, the eleventh thermally tuned phase shifter 110414 is adjusted to a phase of π / 2.

[0073] In step S2, the continuous light sent by the off-chip laser is coupled into the waveguide through the sixth fiber coupler 2118 and enters the receiving and decoding end chip 21. At the same time, it is observed using an off-chip photodetector connected to the fourteenth fiber coupler 2111 and the fifteenth fiber coupler 2112. By adjusting the twelfth thermally tuned phase shifter 21032, the intensity of the light output from the fourteenth fiber coupler 2111 is 9 times the intensity of the light output from the fifteenth fiber coupler 2112.

[0074] In step S3, the pulse light emitted by the off-chip laser, whose relative phase is 0 and whose pulse time interval is the same as the delay of the third delay line 210513, is coupled into the waveguide through the sixteenth fiber coupler 2113 and enters the twenty-third beam splitter 210509. The seventeenth thermally tuned phase shifter 210510 and the twenty-first thermally tuned phase shifter 210514 are adjusted so that the extinction ratio between the fifth single-photon detector 27 and the sixth single-photon detector 28 is maximized. At this time, it indicates that the insertion loss between the third delay line 210513 and the twenty-first thermally tuned phase shifter 210514 has been balanced, and the phase of the twenty-first thermally tuned phase shifter 210514 is 0.

[0075] In step S4, the pulse light emitted by the off-chip laser, whose relative phase is 0 and whose pulse time interval is the same as the delay of the fourth delay line 210521, is coupled into the waveguide through the eighth optical fiber coupler 2120 and enters the twenty-sixth beam splitter 210516. The nineteenth thermally tuned phase shifter 210517 and the twenty-second thermally tuned phase shifter 210520 are adjusted so that the extinction ratio between the seventh single-photon detector 29 and the eighth single-photon detector 210 is maximized. At this time, it indicates that the insertion loss between the fourth delay line 210521 and the twenty-second thermally tuned phase shifter 210520 has been balanced, and the phase of the twenty-second thermally tuned phase shifter 210520 is 0. The twenty-second thermally tuned phase shifter 210520 is further adjusted so that the extinction ratio between the seventh single-photon detector 29 and the eighth single-photon detector 210 is minimized. At this time, it indicates that the working phase of the twenty-second thermally tuned phase shifter 210520 is π / 2.

[0076] In step S5, the pulse light emitted by the off-chip laser with a relative phase of 0 and a pulse time interval the same as the delay of the first delay line 210505 is coupled into the waveguide through the seventh optical fiber coupler 2119 and enters the second beam splitter 210501. The fourteenth thermally tuned phase shifter 210502 is adjusted to maximize the extinction ratio between the fifth single-photon detector 27 and the sixth single-photon detector 28. At this time, it indicates that the insertion loss between the first delay line 210505 and the second delay line 210506 and the sixteenth thermally tuned phase shifter 210507 has been balanced.

[0077] At this point, after steps S2, S3, S4, and S5, the debugging of the phase decoding module 2105 is completed. The delays of the first delay line 210505, the second delay line 210506, the third delay line 210513, and the fourth delay line 210521 are the same and equal to the time interval between adjacent pulses of the signal light.

[0078] Step S6: Continuous light is transmitted using the first laser 12. The continuous light enters the transmitting encoding end chip 11 through the first fiber coupler 1101, passes through the first beam splitter 110301, and is modulated into a pulsed light sequence by adjusting the phase difference between the first carrier dispersion type phase shifter 110304 and the second carrier dispersion type phase shifter 110306 to 0 or π. The continuous light is then output from the second beam splitter 110302.

[0079] Step S7, the pulse light modulated in step S6 enters the third beam splitter 110308 for basis vector selection, and four adjacent pulse sequences are selected as a group. When modulating the time basis vector, by adjusting the phase difference between the third carrier dispersion type phase shifter 110311 and the fourth carrier dispersion type phase shifter 110313 to 0 or π, if the first pulse of the four adjacent pulses is made to interfere constructively at the fourth beam splitter 110309, and the other three pulses are made to interfere destructively at the fourth beam splitter 110309, this corresponds to the |t0> state under the time basis vector; if the second pulse of the four adjacent pulses is made to interfere constructively at the fourth beam splitter 110309, then the |t0> state corresponds to the time basis vector; The four pulses interfere constructively at beam splitter 110309, while the other three pulses interfere destructively at the fourth beam splitter 110309. This corresponds to the |t1> state under the time basis. If the third pulse of the four adjacent pulses interfere constructively at the fourth beam splitter 110309, the other three pulses interfere destructively at the fourth beam splitter 110309. This corresponds to the |t2> state under the time basis. If the fourth pulse of the four adjacent pulses interfere constructively at the fourth beam splitter 110309, the other three pulses interfere destructively at the fourth beam splitter 110309. This corresponds to the |t3> state under the time basis. When modulating the phase basis, the phase difference between the third carrier dispersion phase shifter 110311 and the fourth carrier dispersion phase shifter 110313 is adjusted to 0, so that the four adjacent pulses all interfere constructively at the fourth beam splitter 110309 and enter the next level of modulation.

[0080] In step S8, the pulsed light modulated in step S7 enters the fifth beam splitter 110315 for intensity modulation of the trapped state. By adjusting the phase difference between the fifth carrier dispersion phase shifter 110318 and the sixth carrier dispersion phase shifter 110320, the intensities of the signal state and the trapped state meet the experimental requirements. It should be noted that the intensity of the time basis vector must be twice the intensity of the phase basis vector.

[0081] In step S9, the pulse light modulated by the three-intensity joint modulation module 1103 needs to be modulated by the phase modulation module 1104 to complete the preparation of the quantum state. In particular, the adjustment of the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 adopts a dual-arm drive push-pull adjustment method (push-pull) to generate a phase modulation signal. For the four time states |t0>, |t1>, |t2>, |t3> prepared by the phase modulation module 1104, it is necessary to adjust the electrical signals loaded on the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407, and adjust the electrical signals loaded on the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411, so that the phase difference between the optical signal after combining on the twelfth beam splitter 110415 and the optical signal before splitting on the seventh beam splitter 110401 is 0. For the phase basis vector, if the electrical signals loaded on the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 are adjusted, and the electrical signals loaded on the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411 are adjusted so that the phase difference between the optical signal after combining at the twelfth beam splitter 110415 and the optical signal before splitting at the seventh beam splitter 110401 is 0, then the phase basis vector |f 0> state; if the electrical signals loaded on the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 are adjusted, and the electrical signals loaded on the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411 are adjusted so that the phase difference between the optical signal after beam combination at the twelfth beam splitter 110415 and the optical signal before beam splitting at the seventh beam splitter 110401 is π / 2, then the phase basis vector |f1 can be completed. > state; if the electrical signals loaded on the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 are adjusted, and the electrical signals loaded on the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411 are adjusted so that the phase difference between the optical signal after combining at the twelfth beam splitter 110415 and the optical signal before splitting at the seventh beam splitter 110401 is π, then the |f2> state under the phase basis vector can be achieved; If the electrical signals applied to the seventh carrier dispersion type phase shifter 110405 and the eighth carrier dispersion type phase shifter 110407 are adjusted, and the electrical signals applied to the ninth carrier dispersion type phase shifter 110409 and the tenth carrier dispersion type phase shifter 110411 are adjusted so that the phase difference between the optical signal after combining at the twelfth beam splitter 110415 and the optical signal before splitting at the seventh beam splitter 110401 is 3π / 2, then the |f3> state under the phase basis vector can be achieved;

[0082] Step S10: Finally, the pulse light output from the phase modulation module 1104 is attenuated to the single-photon level by the variable optical attenuator 110503 in the multiplexing module 1105 and then output through the tenth de-beam splitter 110503. Simultaneously, the synchronization light enters the chip from the second laser 13 via the second fiber coupler 1102, passes through the fourteenth beam splitter 110505, and is multiplexed with the signal light output from the tenth de-beam splitter 110503 at the multiplexer 110504 before being output to an optical fiber outside the chip via the fourth fiber coupler 1112.

[0083] Step S11: The optical pulse transmitted through the optical fiber enters the receiving decoding end chip 21 through the fifth optical fiber coupler 2101 and is demultiplexed by the demultiplexer 2102. The synchronization light is output to the off-chip photodetector 22 through the ninth optical fiber coupler 2106. The signal light is split by the variable optical beam splitting module 2103 and then transmitted to the time-based decoding module 2104 or the phase-based decoding module 2105 for decoding. The decoded signal is transmitted by the first single-photon detector 23 connected to the tenth optical fiber coupler 2107 and the eleventh optical fiber coupler 210 8, the third single-photon detector 25 connected to the twelfth fiber coupler 2109, the fourth single-photon detector 26 connected to the thirteenth fiber coupler 2110, the fifth single-photon detector 27 connected to the seventeenth fiber coupler 2114, the sixth single-photon detector 28 connected to the eighteenth fiber coupler 2115, the seventh single-photon detector 29 connected to the nineteenth fiber coupler 2116, and the eighth single-photon detector 210 connected to the twentieth fiber coupler 2117. If the first single-photon detector 23, the second single-photon detector 24, the third single-photon detector 25, and the fourth single-photon detector 26 respond, it means that the time base signal has been detected, and the four time states |t0>, |t1>, |t2>, and |t3> are calibrated according to the arrival time. If the fifth single-photon detector 27 responds, it indicates that the |f0> state under the phase basis vector has been detected; if the sixth single-photon detector 28 responds, it indicates that the |f1> state under the phase basis vector has been detected; if the seventh single-photon detector 29 responds, it indicates that the |f2> state under the phase basis vector has been detected; and if the eighth single-photon detector 210 responds, it indicates that the |f3> state under the phase basis vector has been detected.

[0084] In step S12, the communicating parties can finally generate a security key after coordinating the basis vector and post-processing the data.

[0085] According to the method of the second embodiment, the HD-QKD protocol based on time phase coding can be implemented.

[0086] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

[0087] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

Claims

1. An integrated chip-based high-dimensional quantum key distribution system, characterized by: It includes a first laser, a second laser, a transmitting encoding end chip, a receiving decoding end chip, a photodetector, a first single photon detector, a second single photon detector, a third single photon detector, a fourth single photon detector, a fifth single photon detector, a sixth single photon detector, a seventh single photon detector and an eighth single photon detector; The first laser and the second laser are both connected to the transmitting encoding end chip, the transmitting encoding end chip is connected to the receiving decoding end chip, and the receiving decoding end chip is respectively connected to the photodetector, the first single-photon detector, the second single-photon detector, the third single-photon detector, the fourth single-photon detector, the fifth single-photon detector, the sixth single-photon detector, the seventh single-photon detector, and the eighth single-photon detector; The transmitting coding end chip includes a first fiber coupler, a second fiber coupler, a three-intensity joint modulation module, a phase modulation module, a multiplexing module, a third fiber coupler and a fourth fiber coupler; The first optical fiber coupler is connected to the three-intensity joint modulation module, the three-intensity joint modulation module is connected to the phase modulation module, the phase modulation module is connected to the multiplexing module, and the multiplexing module is connected to the second optical fiber coupler, the third optical fiber coupler, and the fourth optical fiber coupler respectively; The receiving and decoding end chip includes a fifth fiber coupler, a sixth fiber coupler, a seventh fiber coupler, an eighth fiber coupler, a ninth fiber coupler, a tenth fiber coupler, an eleventh fiber coupler, a twelfth fiber coupler, a thirteenth fiber coupler, a fourteenth fiber coupler, a fifteenth fiber coupler, a sixteenth fiber coupler, a seventeenth fiber coupler, an eighteenth fiber coupler, a nineteenth fiber coupler, a twentieth fiber coupler, a demultiplexer, a variable optical beam splitting module, a time-based decoding module, and a phase-based decoding module. The fifth fiber coupler is connected to the demultiplexer, the demultiplexer is respectively connected to the ninth fiber coupler and the variable optical beam splitting module, the variable optical beam splitting module is respectively connected to the time-base decoding module and the phase-base decoding module, the time-base decoding module is respectively connected to the tenth fiber coupler, the eleventh fiber coupler, the twelfth fiber coupler, and the thirteenth fiber coupler, and the phase-base decoding module is respectively connected to the sixteenth fiber coupler, the seventeenth fiber coupler, the eighteenth fiber coupler, the nineteenth fiber coupler, and the twentieth fiber coupler.

2. The integrated chip-based high-dimensional quantum key distribution system according to claim 1, characterized in that: The triple-intensity joint modulation module includes a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, and a sixth beam splitter; Two optical arms are provided between the first beam splitter and the second beam splitter. A first thermally tuned phase shifter and a first carrier dispersion phase shifter are connected in series on the first optical arm, and a second thermally tuned phase shifter and a second carrier dispersion phase shifter are connected in series on the second optical arm. The first thermally tuned phase shifter and the second thermally tuned phase shifter are both connected to the first beam splitter, and the first carrier dispersion phase shifter and the second carrier dispersion phase shifter are both connected to the second beam splitter. A first optical power detector is also connected to the second beam splitter. The first beam splitter is connected to the first optical fiber coupler. Two optical arms are provided between the third beam splitter and the fourth beam splitter. A third thermally tuned phase shifter and a third carrier dispersion phase shifter are connected in series on the first optical arm, and a fourth thermally tuned phase shifter and a fourth carrier dispersion phase shifter are connected in series on the second optical arm. The third thermally tuned phase shifter and the fourth thermally tuned phase shifter are both connected to the third beam splitter, and the third carrier dispersion phase shifter and the fourth carrier dispersion phase shifter are both connected to the fourth beam splitter. A second optical power detector is also connected to the fourth beam splitter. The second beam splitter is connected to the third beam splitter. Two optical arms are provided between the fifth beam splitter and the sixth beam splitter. A fifth thermally tuned phase shifter and a fifth carrier dispersion phase shifter are connected in series on the first optical arm, and a sixth thermally tuned phase shifter and a sixth carrier dispersion phase shifter are connected in series on the second optical arm. The fifth thermally tuned phase shifter and the sixth thermally tuned phase shifter are both connected to the fifth beam splitter, and the fifth carrier dispersion phase shifter and the sixth carrier dispersion phase shifter are both connected to the sixth beam splitter. A third optical power detector is also connected to the sixth beam splitter. The fourth beam splitter is connected to the fifth beam splitter.

3. The integrated chip-based high-dimensional quantum key distribution system according to claim 2, characterized in that: The phase modulation module includes a seventh beam splitter, an eighth beam splitter, a ninth beam splitter, a tenth beam splitter, an eleventh beam splitter, and a twelfth beam splitter; Two optical arms are provided between the eighth beam splitter and the ninth beam splitter. A seventh thermally tuned phase shifter and a seventh carrier dispersion phase shifter are connected in series on the first optical arm, and an eighth thermally tuned phase shifter and an eighth carrier dispersion phase shifter are connected in series on the second optical arm. The seventh thermally tuned phase shifter and the eighth thermally tuned phase shifter are both connected to the eighth beam splitter, and the seventh carrier dispersion phase shifter and the eighth carrier dispersion phase shifter are both connected to the ninth beam splitter. Two optical arms are provided between the tenth beam splitter and the eleventh beam splitter. A ninth thermally tuned phase shifter and a ninth carrier dispersion type phase shifter are connected in series on the first optical arm, and a tenth thermally tuned phase shifter and a tenth carrier dispersion type phase shifter are connected in series on the second optical arm. The ninth thermally tuned phase shifter and the tenth thermally tuned phase shifter are both connected to the tenth beam splitter, and the ninth carrier dispersion type phase shifter and the tenth carrier dispersion type phase shifter are both connected to the eleventh beam splitter. The sixth beam splitter is connected to the seventh beam splitter, the seventh beam splitter is connected to the eighth beam splitter and the tenth beam splitter respectively, the ninth beam splitter is connected to the twelfth beam splitter, and the eleventh beam splitter is connected to the twelfth beam splitter via the eleventh thermally tuned phase shifter.

4. The integrated chip-based high-dimensional quantum key distribution system according to claim 3, characterized in that: The multiplexing modules respectively include a thirteenth beam splitter, a variable optical attenuator, a fourth optical power detector, a multiplexer, a fourteenth beam splitter, and a fifth optical power detector; The thirteenth beam splitter is respectively connected to the variable optical attenuator and the fourth optical power detector; the variable optical attenuator is connected to the twelfth beam splitter; the thirteenth beam splitter is also respectively connected to the third optical fiber coupler and the multiplexer; the multiplexer is respectively connected to the fourth optical fiber coupler and the fourteenth beam splitter; the fourteenth beam splitter is also respectively connected to the second optical fiber coupler and the fifth optical power detector.

5. The integrated chip-based high-dimensional quantum key distribution system according to claim 1, characterized in that: The variable optical beam splitting module includes a fifteenth beam splitter and a sixteenth beam splitter, two optical arms are provided between the fifteenth beam splitter and the sixteenth beam splitter, and a twelfth thermally tunable phase shifter and a thirteenth thermally tunable phase shifter are provided on the two optical arms respectively; the fifteenth beam splitter is respectively connected to the demultiplexer and the sixth optical fiber coupler, and the sixteenth beam splitter is respectively connected to the time-based decoding module, the fourteenth optical fiber coupler, the fifteenth optical fiber coupler and the phase-based decoding module.

6. The integrated chip-based high-dimensional quantum key distribution system according to claim 5, characterized in that: The time base decoding module includes a seventeenth beam splitter, an eighteenth beam splitter and a nineteenth beam splitter, the seventeenth beam splitter is connected to the eighteenth beam splitter and the nineteenth beam splitter respectively; the sixteenth beam splitter is connected to the seventeenth beam splitter, the eighteenth beam splitter is connected to the tenth fiber coupler and the eleventh fiber coupler respectively, and the nineteenth beam splitter is connected to the twelfth fiber coupler and the thirteenth fiber coupler respectively.

7. The integrated chip-based high-dimensional quantum key distribution system according to claim 5, characterized in that: The phase-based decoding module adopts a cascaded tree interferometer structure, including a 20th beam splitter, a 21st beam splitter, a 22nd beam splitter, a 23rd beam splitter, a 24th beam splitter, a 25th beam splitter, a 26th beam splitter, a 27th beam splitter and a 28th beam splitter; Two optical arms are provided between the second demultiplexer and the twenty-first beam splitter, a fourteenth thermally tuned phase shifter is provided on the first optical arm, and a fifteenth thermally tuned phase shifter is provided on the second optical arm; the sixteenth beam splitter is connected to the second demultiplexer; two optical arms are provided between the twenty-first beam splitter and the twenty-second beam splitter, a first delay line and a second delay line are connected in series on the first optical arm, and a sixteenth thermally tuned phase shifter is provided on the second optical arm; the first delay line is connected to the twenty-first beam splitter, and the second delay line is connected to the twenty-second beam splitter; Two optical arms are provided between the twenty-third beam splitter and the twenty-fourth beam splitter, the first optical arm being provided with a seventeenth thermally tuned phase shifter, and the second optical arm being provided with an eighteenth thermally tuned phase shifter; the twenty-second beam splitter is connected to the twenty-third beam splitter, which is also connected to the sixteenth optical fiber coupler; two optical arms are provided between the twenty-fourth beam splitter and the twenty-fifth beam splitter, the first optical arm being provided with a third delay line, and the second optical arm being provided with a twenty-first thermally tuned phase shifter; the twenty-fifth beam splitter is connected to the seventeenth optical fiber coupler and the eighteenth optical fiber coupler, respectively; Two optical arms are provided between the twenty-sixth beam splitter and the twenty-seventh beam splitter, the first optical arm is provided with a nineteenth thermally tuned phase shifter, and the second optical arm is provided with a twentieth thermally tuned phase shifter; the twenty-second beam splitter is connected to the twenty-sixth beam splitter, and the twenty-sixth beam splitter is also connected to the eighth optical fiber coupler; two optical arms are provided between the twenty-seventh beam splitter and the twenty-eighth beam splitter, the first optical arm is provided with a twenty-second thermally tuned phase shifter, and the second optical arm is provided with a fourth delay line; the twenty-eighth beam splitter is connected to the nineteenth optical fiber coupler and the 20th optical fiber coupler, respectively.

8. The integrated chip-based high-dimensional quantum key distribution system according to any one of claim 1, characterized in that: The first laser is connected to the first fiber coupler via an optical fiber, the second laser is connected to the second fiber coupler via an optical fiber, the transmission encoding end chip is connected via a silicon-based optical waveguide, the reception decoding end chip is connected via a silicon nitride optical waveguide, the transmission encoding end chip is connected to the reception decoding end chip via an optical fiber, the ninth fiber coupler is connected to the photodetector via an optical fiber, the tenth fiber coupler is connected to the first single-photon detector via an optical fiber, the eleventh fiber coupler is connected to the second single-photon detector via an optical fiber, the twelfth fiber coupler is connected to the third single-photon detector via an optical fiber, the thirteenth fiber coupler is connected to the fourth single-photon detector via an optical fiber, the seventeenth fiber coupler is connected to the fifth single-photon detector via an optical fiber, the eighteenth fiber coupler is connected to the sixth single-photon detector via an optical fiber, the nineteenth fiber coupler is connected to the seventh single-photon detector via an optical fiber, and the twentieth fiber coupler is connected to the eighth single-photon detector via an optical fiber.

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