Teaching system of discrete phase coded quantum key distribution protocol based on optical chip

Abstract

The present invention provides a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip. The encoding and decoding ends of the teaching system are both manufactured based on the optical chip. The entire system has the advantages of low cost, modularization, and convenient teaching. It makes up for the problem that the existing commercial quantum key distribution system cannot be used for physics teaching in colleges and universities as well as junior and senior high schools due to its high cost and large size.

Description

Technical Field

[0001] The present invention relates to the technical field of physics teaching products, and more specifically, to a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip applied to physics teaching. Background Art

[0002] With the continuous development of science and technology, quantum information technology has also developed rapidly. Relevant products in major application directions such as quantum cryptography, quantum computing and quantum measurement have gradually moved from laboratory research to engineering practice. The rapid development of emerging technologies cannot be separated from a group of professional quantum information engineering and technical talents. At the same time, the country has also established an undergraduate discipline of quantum information, aiming to cultivate professional and technical talents in quantum information.

[0003] For talent cultivation, textbooks and teaching experimental systems are particularly important. However, traditional quantum information systems are expensive and large in size, which is not conducive to promotion in ordinary universities, junior high schools and high schools, and hinders the development of quantum information-related disciplines. Summary of the invention

[0004] In view of this, in order to solve the above problems, the present invention provides a teaching system of discrete phase coded quantum key distribution protocol based on optical chip, and the technical solution is as follows:

[0005] A teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip, the teaching system comprising:

[0006] A laser module, wherein the laser module is used to emit an optical pulse signal with a certain repetition frequency;

[0007] At least four two-arm unequal-arm interferometer chip modules and at least one three-arm unequal-arm interferometer chip module, wherein the two-arm unequal-arm interferometer chip module and the three-arm unequal-arm interferometer chip module are at least used for phase modulation of optical pulses;

[0008] At least two adjustable optical attenuators, the adjustable optical attenuators are used to strongly attenuate the optical pulses so as to attenuate the optical pulses to a light intensity close to a single-photon level;

[0009] at least two single photon detector modules, the single photon detector modules being used to respond to received light intensities at the single photon level;

[0010] A signal acquisition module, wherein the signal acquisition module is used to collect the detection signal of the single-photon detector module and send it to an operation platform;

[0011] The operating platform is equipped with at least one software for demonstrating corresponding experimental phenomena.

[0012] Preferably, in the above teaching system, the teaching system further comprises:

[0013] A passive optical component group, wherein the passive optical component group is used to realize the connection of various components in the teaching system.

[0014] Preferably, in the above teaching system, the laser module is a DFB laser module;

[0015] The DFB laser module includes a DFB laser diode and a driving circuit board.

[0016] Preferably, in the above teaching system, the two-arm unequal-arm interferometer chip module comprises:

[0017] Two waveguide lines, one of which is a time-delay waveguide line, and the other waveguide line is provided with a thermal phase modulation module;

[0018] The parts of the two waveguide lines located at the input ends are provided with waveguide beam splitters;

[0019] The parts of the two waveguide lines located at the output ends are provided with waveguide combiners.

[0020] Preferably, in the above teaching system, the two-arm unequal-arm interferometer chip module further includes:

[0021] A temperature modulation device is used to maintain the temperature of the two-arm unequal-arm interferometer chip module.

[0022] Preferably, in the above teaching system, the three-arm unequal-arm interferometer chip module comprises:

[0023] Three waveguide lines, wherein the first waveguide line, the second waveguide line and the third waveguide line are all provided with a thermal phase modulation module;

[0024] The second waveguide wire and the third waveguide wire are both delay waveguide wires, and the delay time of the third waveguide wire is greater than the delay time of the second waveguide wire;

[0025] The first waveguide wire and the second waveguide wire are provided with a first waveguide beam splitter at the input end;

[0026] The second waveguide wire and the third waveguide wire are provided with a second waveguide beam splitter at the input end;

[0027] The second waveguide wire and the third waveguide wire are provided with a first waveguide combiner at the output end;

[0028] The parts of the first waveguide wire and the second waveguide wire located at the output ends are provided with a second waveguide combiner.

[0029] Preferably, in the above teaching system, the three-arm unequal-arm interferometer chip module further includes:

[0030] A temperature modulation device is used to maintain the temperature of the three-arm unequal-arm interferometer chip module.

[0031] Preferably, in the above teaching system, the software includes:

[0032] BB84 protocol result statistics and bit rate calculation software;

[0033] DPS protocol result statistics and bit rate calculation software;

[0034] Beam attack demonstration software.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention provides a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip, comprising: a laser module, the laser module being used to emit an optical pulse signal with a certain repetition frequency; at least four two-arm unequal-arm interferometer chip modules and at least one three-arm unequal-arm interferometer chip module, the two-arm unequal-arm interferometer chip module and the three-arm unequal-arm interferometer chip module being used at least to perform phase modulation on optical pulses; at least two adjustable optical attenuators, the adjustable optical attenuators being used to perform strong attenuation processing on optical pulses so as to attenuate them to a light intensity close to a single-photon level; at least two single-photon detector modules, the single-photon detector modules being used to respond to a received light intensity at a single-photon level; a signal acquisition module, the signal acquisition module being used to collect detection signals of the single-photon detector modules and send them to an operating platform; the operating platform being equipped with at least one software for performing corresponding experimental phenomenon demonstrations. This teaching system is based on a simple system structure and does not require high parameters. Compared with the commercial phase-coded quantum key distribution system, it has the advantages of low cost, small size, clear principle demonstration, and easy teaching. Ultimately, the relevant teaching experiments of discrete phase-coded quantum key distribution technology will be promoted to ordinary universities and junior and senior high school teaching. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0038] Figure 1 A schematic diagram of the composition of a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip provided by an embodiment of the present invention;

[0039] Figure 2 A schematic structural diagram of a two-arm unequal-arm interferometer chip module provided by an embodiment of the present invention;

[0040] Figure 3 A schematic structural diagram of a three-arm unequal-arm interferometer chip module provided by an embodiment of the present invention;

[0041] Figure 4 A schematic diagram of an integrated packaging system for a discrete phase coded quantum key distribution protocol teaching system based on an optical chip provided by an embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a BB84 phase coding protocol demonstration experiment system based on BB84 protocol result statistics and code rate calculation software provided in an embodiment of the present invention;

[0043] Figure 6 A codec table of the BB84 protocol provided in an embodiment of the present invention;

[0044] Figure 7 A schematic diagram of a DPS phase coding protocol demonstration experiment system based on DPS protocol result statistics and bit rate calculation software provided in an embodiment of the present invention;

[0045] Figure 8 A schematic diagram of a beam attack demonstration experiment system based on beam attack demonstration software provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 creative work are within the scope of protection of the present invention.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] refer to Figure 1 , Figure 1 A schematic diagram of the composition of a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip provided in an embodiment of the present invention.

[0049] The teaching system comprises:

[0050] The laser module 11 is used to emit an optical pulse signal with a certain repetition frequency.

[0051] At least four two-arm unequal-arm interferometer chip modules 12 and at least one three-arm unequal-arm interferometer chip module 13, wherein the two-arm unequal-arm interferometer chip module 12 and the three-arm unequal-arm interferometer chip module 13 are at least used for phase modulation of optical pulses.

[0052] At least two adjustable optical attenuators 14 are used to strongly attenuate the optical pulses so as to attenuate the optical pulses to a light intensity close to the single photon level. Optionally, the adjustable optical attenuators 14 can be ordinary commercial adjustable optical attenuators.

[0053] At least two single-photon detector modules 15, the single-photon detector modules 15 are used to respond to the light intensity at the received single-photon level. Optionally, the single-photon detector module 15 can be an avalanche photodiode made of indium gallium arsenide material, and a corresponding driving circuit to achieve the response to the light intensity at the received single-photon level.

[0054] The signal acquisition module 16 is used to collect the detection signal of the single photon detector module 15 and send it to the operation platform. Optionally, the signal acquisition module 16 can be a commercial data acquisition card.

[0055] The operating platform 17 is equipped with at least one software for performing corresponding experimental phenomenon demonstration.

[0056] Optionally, the operating platform 17 is equipped with a series of software for data statistics and data processing, and can also be replaced by a desktop computer or other types of host computers.

[0057] In this embodiment, the laser module 11 includes but is not limited to a DFB laser module. When the laser module 11 is a DFB laser module, the DFB laser module at least includes a DFB laser diode and a corresponding driving circuit board. The driving circuit board is used to control the working state of the DFB laser diode, at least to make the DFB laser diode emit an optical pulse signal with a certain repetition frequency.

[0058] Furthermore, among the at least four two-arm unequal-arm interferometer chip modules 12, any two-arm unequal-arm interferometer chip module 12 is made of materials such as silicon-based silicon dioxide or silicon on insulator, and has an unequal-arm Mach-Zehnder interferometer structure with a specific delay difference, and at least one arm of the interferometer structure has a thermally adjusted phase.

[0059] Specifically, refer to Figure 2 , Figure 2 A schematic structural diagram of a two-arm unequal-arm interferometer chip module provided in an embodiment of the present invention.

[0060] The two-arm unequal-arm interferometer chip module 12 comprises:

[0061] There are two waveguide lines, one of which is a delay waveguide line, and the other waveguide line is provided with a thermal phase modulation module 19.

[0062] The parts of the two waveguide lines located at the input ends are provided with waveguide beam splitters.

[0063] The parts of the two waveguide lines located at the output ends are provided with waveguide combiners.

[0064] The two-arm unequal-arm interferometer chip module 12 is formed based on an optical chip structure.

[0065] Among them, Figure 2 As shown, the two-arm unequal-arm interferometer chip module 12 also includes:

[0066] The temperature modulation device 20 is used to maintain the temperature of the two-arm unequal-arm interferometer chip module 12 .

[0067] Optionally, the temperature modulation device 20 includes but is not limited to a ceramic electrically controlled temperature modulation device, which is used to maintain the temperature of the two-arm unequal-arm interferometer chip module 12 to avoid affecting the phase modulation, so that the phase modulation is modulated based on the operating voltage of the thermal phase modulation module 19.

[0068] Furthermore, at least one three-arm unequal-arm interferometer chip module 13 is made of materials such as silicon-based silicon dioxide or silicon on insulator, which can be regarded as a combination of two Mach-Zehnder interferometers, in which a thermally tuned phase modulation module exists on any arm of the interferometer.

[0069] Specifically, refer to Figure 3 , Figure 3 A schematic structural diagram of a three-arm unequal-arm interferometer chip module provided in an embodiment of the present invention.

[0070] The three-arm unequal-arm interferometer chip module 13 comprises:

[0071] There are three waveguide lines, wherein the first waveguide line, the second waveguide line and the third waveguide line are all provided with a thermal phase modulation module 19 .

[0072] The second waveguide wire and the third waveguide wire are both delay waveguide wires, and the delay time of the third waveguide wire is greater than the delay time of the second waveguide wire.

[0073] Portions of the first waveguide wire and the second waveguide wire located at the input end are provided with a first waveguide beam splitter.

[0074] The second waveguide wire and the third waveguide wire portions located at the input ends are provided with a second waveguide beam splitter.

[0075] The second waveguide wire and the third waveguide wire portions located at the output ends are provided with a first waveguide combiner.

[0076] The parts of the first waveguide wire and the second waveguide wire located at the output ends are provided with a second waveguide combiner.

[0077] The three-arm unequal-arm interferometer chip module 13 is formed based on an optical chip structure.

[0078] Among them, Figure 3 As shown, the three-arm unequal-arm interferometer chip module 13 also includes:

[0079] The temperature modulation device 20 is used to maintain the temperature of the three-arm unequal-arm interferometer chip module 13 .

[0080] Optionally, the temperature modulation device 20 includes but is not limited to a ceramic electrically controlled temperature modulation device, which is used to maintain the temperature of the three-arm unequal-arm interferometer chip module 13 to avoid affecting the phase modulation, so that the phase modulation is modulated based on the operating voltage of the thermal phase modulation module 19.

[0081] Optional, such as Figure 1 As shown, the teaching system also includes:

[0082] The passive optical component group 18 is used to realize the connection of various components in the teaching system.

[0083] Specifically, the passive optical component group 18 at least includes passive optical components such as optical fiber jumpers and optical fiber beam splitters, which are used to achieve the connection between various components in the teaching system.

[0084] Optional, such as Figure 1 As shown, the software installed in the operating platform 17 at least includes:

[0085] BB84 protocol result statistics and bit rate calculation software.

[0086] DPS protocol result statistics and bit rate calculation software.

[0087] Beam attack demonstration software.

[0088] Among them, the BB84 protocol result statistics and code rate calculation software includes a protocol demonstration video tutorial and data statistical analysis software, which allows users to perform statistics on encoded data and decoded data, and perform code rate calculations and experimental phenomenon demonstrations based on the BB84 quantum key distribution protocol.

[0089] Among them, the DPS protocol result statistics and bit rate calculation software includes a protocol demonstration video tutorial and data statistical analysis software, which allows users to perform statistics on encoded data and decoded data, and perform bit rate calculations and experimental phenomenon demonstrations based on the DPS quantum key distribution protocol.

[0090] Among them, the beam attack demonstration software includes a protocol demonstration video tutorial and data statistical analysis software, which allows users to perform statistics on encoded data and decoded data, and calculate the bit rate of attackers and legitimate users based on the beam attack plan for the BB84 protocol, as well as demonstrate experimental phenomena.

[0091] It can be seen that the teaching system is based on a simple system structure and does not require high parameter requirements. Compared with the commercial phase-coded quantum key distribution system, it has the advantages of low cost, small size, clear principle demonstration, and easy teaching. Ultimately, the relevant teaching experiments of discrete phase-coded quantum key distribution technology will be promoted to ordinary universities and junior and senior high school teaching.

[0092] Further, in another embodiment of the present invention, referring to Figure 4 , Figure 4 A schematic diagram of the integrated packaging of a teaching system for a discrete phase-coded quantum key distribution protocol based on an optical chip provided in an embodiment of the present invention.

[0093] like Figure 4 As shown, in order to further improve the convenience of educational experiments, the product appearance of the teaching system can be a portable experimental box, in which a laser module 11, a two-arm unequal-arm interferometer chip module 12, a three-arm unequal-arm interferometer chip module 13, an adjustable optical attenuator 14, a single-photon detector module 15, a signal acquisition module 16, a passive optical component group 18 and an operating platform 17 are integrated. The operating platform 17 is equipped with at least one software for demonstrating corresponding experimental phenomena.

[0094] Optionally, the operating platform 17 may be an electronic device such as a tablet notebook.

[0095] The integrated optical chip device module includes at least four two-arm unequal-arm interferometer chip modules 12 and at least one three-arm unequal-arm interferometer chip module 13 .

[0096] In the following, different software demonstration experiments are demonstrated in combination with a teaching system for a discrete phase coded quantum key distribution protocol based on an optical chip provided in the above embodiment of the present invention:

[0097] 1. Reference Figure 5 , Figure 5 A schematic diagram of a BB84 phase coding protocol demonstration experiment system based on BB84 protocol result statistics and code rate calculation software provided in an embodiment of the present invention.

[0098] At the protocol transmitting end, the DFB laser module emits a series of continuous optical pulse signals at a certain repetition frequency. Each of these continuous optical pulses is equivalent, and a single optical pulse is used for explanation below.

[0099] The optical pulse enters the unequal-arm interferometer chip module 1 (i.e., a two-arm unequal-arm interferometer chip module 12), and is divided into two optical pulses with equal energy at the waveguide beam splitter located at the input end of the unequal-arm interferometer chip module 1. One of the optical pulses is transmitted through the delay waveguide line, and the other optical pulse is transmitted through the waveguide line provided with a thermally adjustable phase modulation module 19. During this process, the thermally adjustable phase modulation module 19 randomly or autonomously loads one of the four fixed phases φ1=0, pi / 2, pi, 3pi / 2 on the optical pulse.

[0100] Subsequently, the two waveguides are combined by the waveguide combiner at the output end of the unequal-arm interferometer chip module 1 ; the effect after the combination is that two pulses with a fixed phase difference are output through the unequal-arm interferometer chip module 1 .

[0101] like Figure 5 As shown, the continuous light pulse is strongly attenuated by the adjustable optical attenuator to attenuate it to a light intensity close to the single-photon level, which only changes the light intensity of the light pulse.

[0102] The above-mentioned light pulses attenuated by the adjustable optical attenuator enter the unequal-arm interferometer chip module 2 (i.e., another two-arm unequal-arm interferometer chip module 12) at the protocol receiving end. In the unequal-arm interferometer chip module 2, the front and rear light pulses will be split by the waveguide beam splitter located at the input end. The two light pulses passing through the delayed waveguide line are delayed backward by a fixed time relative to the two light pulses passing through the waveguide line equipped with a thermally adjustable phase modulation module 19.

[0103] Since the unequal-arm interferometer chip module 1 and the unequal-arm interferometer chip module 2 at the protocol transmitting end and the protocol receiving end are exactly the same, the front-end light pulses of the two light pulses passing through the delay waveguide wire and the rear-end light pulses of the two light pulses passing through the waveguide wire equipped with the thermally adjustable phase modulation module 19 overlap and interfere with each other at the waveguide combiner at the output end of the unequal-arm interferometer chip module 2 when they arrive at the waveguide combiner.

[0104] At the same time, the two light pulses passing through the waveguide wire equipped with the thermally adjustable phase modulation module 19 are loaded with phase φ2=0, pi / 2 relative to the two light pulses passing through the delayed waveguide wire for base selection measurement, so the final interference result of the two light pulses at the waveguide combiner is determined by the phase difference φ1+φ2.

[0105] If φ1+φ2=0, one of the single-photon detector modules has a detection result; if φ1+φ2=pi, the other single-photon detector module has a detection result; if φ1+φ2=pi / 2 or 3pi / 2, both single-photon detector modules have a general probability of having a detection result.

[0106] refer to Figure 6 , Figure 6 A codec table of the BB84 protocol provided in an embodiment of the present invention.

[0107] After the measurement is completed, the protocol receiver declares to the protocol transmitter whether the randomly selected phase φ2 is 0 or pi / 2. Figure 6 The BB84 protocol encoding and decoding table shown in the figure can obtain the coding result according to the phase value recorded by the current protocol transmitter and the protocol receiver, and use the BB84 protocol result statistics and code rate calculation software to calculate the current bit error rate and code rate.

[0108] In summary, this is the implementation plan of the BB84 phase coding protocol demonstration experiment system. As a basic demonstration teaching experiment, the system fully demonstrates the basic composition of the BB84 protocol system, the protocol encoding and decoding method, and the final key generation method.

[0109] 2. Reference Figure 7 , Figure 7 A schematic diagram of a DPS phase coding protocol demonstration experiment system based on DPS protocol result statistics and bit rate calculation software provided in an embodiment of the present invention.

[0110] At the protocol transmitting end, the DFB laser module emits a series of continuous optical pulse signals at a certain repetition frequency. Each of these continuous optical pulses is equivalent, and a single optical pulse is used for explanation below.

[0111] The optical pulse enters the three-arm unequal-arm interferometer chip module 13, and is divided into three optical pulses with the same energy at the two waveguide beam splitters located at the input end of the three-arm unequal-arm interferometer chip module 13. The delay time between each two is the same. The three optical pulses all pass through the thermally tuned phase modulation module 19, and one of the two fixed phases φ1=0 and pi is loaded on the optical pulse.

[0112] Then, the three optical pulses are combined at two waveguide combiners at the output end of the three-arm unequal-arm interferometer chip module 13; the effect after combining is three optical pulses with fixed delays, and the phase difference between every two optical pulses is φ1.

[0113] like Figure 7 As shown, the continuous light pulse is strongly attenuated by the adjustable optical attenuator to attenuate it to a light intensity close to the single-photon level, which only changes the light intensity of the light pulse.

[0114] The above-mentioned light pulses attenuated by the adjustable optical attenuator enter the two-arm unequal-arm interferometer chip module 12 at the protocol receiving end. In the two-arm unequal-arm interferometer chip module 12, the front and rear three light pulses will be split by the waveguide beam splitter located at the input end. The two light pulses passing through the delayed waveguide are delayed backward by a fixed time relative to the two light pulses passing through the waveguide provided with the thermally adjustable phase modulation module 19.

[0115] Since the unit delay on the three-arm unequal-arm interferometer chip module 13 and the two-arm unequal-arm interferometer chip module 12 at the protocol transmitting end and the protocol receiving end is the same, the two front-end light pulses of the three light pulses passing through the delay waveguide wire and the two rear-end light pulses of the three light pulses passing through the waveguide wire equipped with the thermally adjustable phase modulation module 19 overlap and interfere with each other at the waveguide combiner located at the output end of the two-arm unequal-arm interferometer chip module 12 when they arrive at the two-arm unequal-arm interferometer chip module 12.

[0116] It can be seen at this point that single encoding will cause two interferences on the two-arm unequal-arm interferometer chip module 12 in the protocol receiving end, namely, interference between the first light pulse and the second light pulse, and interference between the second light pulse and the third light pulse.

[0117] According to the interference result, if the phase difference between the two interfering light pulses is 0, the single photon detector module 1 outputs the measurement result; if the phase difference between the two interfering light pulses is pi, the single photon detector module 2 outputs the measurement result.

[0118] In the DPS protocol, the protocol receiver retains the situation where only one of the two interferences has a result. If the single-photon detector module 1 outputs the measurement result, it is recorded as bit 0; if the single-photon detector module 2 outputs the measurement result, it is recorded as bit 1. In this way, the coded result can be obtained, and the DPS protocol result statistics and bit rate calculation software can be used to calculate the current bit error rate and bit rate.

[0119] To sum up, this is the implementation plan of the DPS phase coding protocol demonstration experiment system. As a basic demonstration teaching experiment, the system fully demonstrates the basic composition of the DPS protocol system, the protocol encoding and decoding method, and the final key generation method.

[0120] 3. Reference Figure 8 , Figure 8 A schematic diagram of a beam attack demonstration experiment system based on beam attack demonstration software provided in an embodiment of the present invention.

[0121] At the protocol transmitting end, the DFB laser module emits a series of continuous optical pulse signals at a certain repetition frequency. Each of these continuous optical pulses is equivalent, and a single optical pulse is used for explanation below.

[0122] The optical pulse enters the unequal-arm interferometer chip module 1 (i.e., a two-arm unequal-arm interferometer chip module 12), and is divided into two optical pulses with equal energy at the waveguide beam splitter located at the input end of the unequal-arm interferometer chip module 1. One of the optical pulses is transmitted through the delay waveguide line, and the other optical pulse is transmitted through the waveguide line provided with a thermally adjustable phase modulation module 19. During this process, the thermally adjustable phase modulation module 19 randomly or autonomously loads one of the four fixed phases φ1=0, pi / 2, pi, 3pi / 2 on the optical pulse.

[0123] Subsequently, the two waveguides are combined by the waveguide combiner at the output end of the unequal-arm interferometer chip module 1 ; the effect after the combination is that two pulses with a fixed phase difference are output through the unequal-arm interferometer chip module 1 .

[0124] like Figure 8 As shown, the continuous light pulse is strongly attenuated by the adjustable optical attenuator to attenuate it to a light intensity close to the single-photon level, which only changes the light intensity of the light pulse.

[0125] At the attacking end, the attacking end intercepts the signal transmitted by the protocol transmitting end, and measures the received signal through the implementation rules of the BB84 protocol receiving end mentioned above.

[0126] The attacking end performs quantum state modulation and encoding according to the measured signal in accordance with the BB84 phase coding protocol transmitting end implementation method.

[0127] If the attacker previously selected φ2=0 for measurement, and the single-photon detector module 1 responds at this time, the quantum state is encoded as φ1=0; if the single-photon detector module 2 responds at this time, the quantum state is encoded as φ1=pi.

[0128] If the attacker previously selected φ2=pi / 2 for measurement, and the single-photon detector module 1 responds at this time, the quantum state is encoded as φ1=pi / 2; if the single-photon detector module 2 responds at this time, the quantum state is encoded as φ1=3pi / 2.

[0129] After receiving the quantum state sent by the attacker, the protocol receiving end performs measurement according to the implementation method of the BB84 phase coding protocol receiving end, and Figure 6 The BB84 protocol codec table is shown for decoding. It can be found here that due to the existence of the attacking end, the interception and retransmission attack will cause an additional 25% bit error rate.

[0130] In summary, this is the implementation plan of the interception and retransmission attack demonstration experiment system. As a basic demonstration teaching experiment, the system fully demonstrates the interception and retransmission attack demonstration experiment system, the protocol encoding and decoding method, and the final key generation method.

[0131] In summary, this application proposes a teaching system for a discrete phase-coded quantum key distribution protocol based on an optical chip. The encoding and decoding ends of the teaching system are both made based on optical chips. The entire system has the advantages of low cost, modularity, and convenient teaching. It makes up for the problem that the existing commercial quantum key distribution system cannot be used for physics teaching in colleges and universities as well as junior and senior high schools due to its high cost and large size.

[0132] The above is a detailed introduction to a teaching system for a discrete phase-coded quantum key distribution protocol based on an optical chip provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

[0133] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0134] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A teaching system for discrete phase coded quantum key distribution protocol based on optical chip, characterized in that: The teaching system comprises: A laser module, wherein the laser module is used to emit an optical pulse signal with a certain repetition frequency; At least four two-arm unequal-arm interferometer chip modules and at least one three-arm unequal-arm interferometer chip module, wherein the two-arm unequal-arm interferometer chip module and the three-arm unequal-arm interferometer chip module are at least used for phase modulation of optical pulses; At least two adjustable optical attenuators, the adjustable optical attenuators are used to strongly attenuate the optical pulses so as to attenuate the optical pulses to a light intensity close to a single-photon level; at least two single photon detector modules, the single photon detector modules being used to respond to received light intensities at the single photon level; A signal acquisition module, wherein the signal acquisition module is used to collect the detection signal of the single-photon detector module and send it to an operation platform; The operating platform is equipped with at least one software for performing corresponding experimental phenomenon demonstration; the software includes beam attack demonstration software; the beam attack demonstration software is used to calculate the bit rate of the attacker and the legitimate user according to the beam attack scheme, and to demonstrate the attack experimental phenomenon.

2. The teaching system according to claim 1, characterized in that: The teaching system also includes: A passive optical component group, wherein the passive optical component group is used to realize the connection of various components in the teaching system.

3. The teaching system according to claim 1, characterized in that: The laser module is a DFB laser module; The DFB laser module includes a DFB laser diode and a driving circuit board.

4. The teaching system according to claim 1, characterized in that: The two-arm unequal-arm interferometer chip module comprises: Two waveguide lines, one of which is a time-delay waveguide line, and the other waveguide line is provided with a thermal phase modulation module; The parts of the two waveguide lines located at the input ends are provided with waveguide beam splitters; The parts of the two waveguide lines located at the output ends are provided with waveguide combiners.

5. The teaching system according to claim 4, characterized in that: The two-arm unequal-arm interferometer chip module also includes: A temperature modulation device is used to maintain the temperature of the two-arm unequal-arm interferometer chip module.

6. The teaching system according to claim 1, characterized in that: The three-arm unequal-arm interferometer chip module comprises: Three waveguide lines, wherein the first waveguide line, the second waveguide line and the third waveguide line are all provided with a thermal phase modulation module; The second waveguide wire and the third waveguide wire are both delay waveguide wires, and the delay time of the third waveguide wire is greater than the delay time of the second waveguide wire; The first waveguide wire and the second waveguide wire are provided with a first waveguide beam splitter at the input end; The second waveguide wire and the third waveguide wire are provided with a second waveguide beam splitter at the input end; The second waveguide wire and the third waveguide wire are provided with a first waveguide combiner at the output end; The parts of the first waveguide wire and the second waveguide wire located at the output ends are provided with a second waveguide combiner.

7. The teaching system according to claim 6, characterized in that: The three-arm unequal-arm interferometer chip module also includes: A temperature modulation device is used to maintain the temperature of the three-arm unequal-arm interferometer chip module.

8. The teaching system according to claim 1, characterized in that: The software includes: BB84 protocol result statistics and bit rate calculation software; DPS protocol result statistics and bit rate calculation software; Beam attack demonstration software.

Images