Multi-user QKD system based on OCC code

Abstract

The utility model discloses a multi-user QKD system based on OCC codes. The system comprises a sender and a plurality of receivers. The sender comprises an optical signal generator, an OCC code generator and a modulator; the receiver comprises an optical signal receiver and a demodulator. The utility model discloses a multi-user QKD (Quantum Key Distribution) system based on an OCC (Optical Code Code), which realizes one-to-many multi-user QKD communication by utilizing the OCC (Optical Code Code), better reduces crosstalk among multiple access information, can improve the multi-user capacity with the maximum capacity, and uses the same frequency band to carry out QKD communication in the same channel by utilizing the OCC and a code division multiplexing technology. The system has the advantages of high spectrum utilization rate, large system capacity, strong anti-interference capability and the like, does not occupy too many channel resources, is simple in structure and has expansibility.

Description

Technical Field

[0001] The utility model relates to the field of quantum communication equipment, and particularly relates to a multi-user QKD system based on OCC code. Background Technique

[0002] Quantum Key Distribution (QKD) is a research focus in the field of quantum communication. Based on the characteristics of quantum mechanics, both communicating parties can maintain secure communication in the presence of eavesdropping attempts by eavesdroppers, and the eavesdroppers cannot obtain the communication content.

[0003] Since the BB84 protocol first proposed in 1984, the QKD protocol has developed all the way to the recent TF-QKD protocol. The QKD protocol has become increasingly mature. With the continuous improvement of the protocol, QKD technology has gradually moved towards practical application and commercialization. How to extend QKD technology to multi-user network communication is a key to the practical application of QKD technology in quantum networks.

[0004] Currently, the commonly used technologies for realizing multi-user networks include wavelength division multiplexing technology, time division multiplexing technology, space division multiplexing technology, etc. These technologies can effectively increase the number of channels supported in a shared optical fiber channel and carry a higher communication bandwidth. In wavelength division multiplexing technology, as the number of channels in the transmission system increases, the nonlinear effect of single-mode optical fiber intensifies and has approached the nonlinear Shannon limit; wavelength division multiplexing technology will occupy more and more channel resources for communication, and channel resources are scarce resources. The time division switching required by time division multiplexing technology has high requirements for the storage of quantum states and is in the laboratory stage; the application of space division multiplexing technology needs to be improved and tends to be mature.

[0005] Therefore, there is currently no multiplexing scheme that can effectively realize a multi-user network and does not occupy too many resources. Content of the Utility Model

[0006] In order to solve the problem of a multiplexing scheme that can effectively realize a multi-user network and reduce the consumption of channel resources, the utility model proposes a multi-user QKD system based on OCC code.

[0007] To achieve the above object, the technical solution adopted by the utility model is as follows:

[0008] A multi-user QKD system based on OCC code includes a sender and multiple receivers;

[0009] The sender includes an optical signal generator, an OCC code generator, and a modulator;

[0010] The receiver includes an optical signal receiver and a demodulator;

[0011] The output end of the optical signal generator and one output end of the OCC code generator are respectively connected to different input ends of the modulator; the output end of the optical signal receiver is connected to one input end of the demodulator; the other output end of the OCC code generator is respectively connected to the other input ends of the demodulators of each receiving party; the output end of the modulator is respectively connected to the input ends of the optical signal receivers in each receiving party.

[0012] In the above solution, one-to-many multi-user QKD communication is achieved by using OCC codes (optical orthogonal codes), which can preferably reduce the crosstalk between multi-access information, maximize the improvement of multi-user capacity, use the same frequency band in the same channel for QKD communication by using OCC codes and code division multiplexing technology, and has the advantages of high spectrum utilization rate, large system capacity, strong anti-interference ability, etc., does not occupy too many channel resources, and the system structure is simple and has scalability.

[0013] Preferably, the sending party further includes a quantum random number generator;

[0014] The output end of the quantum random number generator is connected to one input end of the modulator.

[0015] Preferably, the output end of the modulator is respectively connected to the input ends of the optical signal receivers in each receiving party through a quantum channel.

[0016] Preferably, it further includes a coupler; the output end of the modulator is connected to the input end of the coupler through a quantum channel, and the output end of the coupler is respectively connected to the input ends of the optical signal receivers in each receiving party through a quantum channel.

[0017] Preferably, the average photon number of the optical pulse sequence generated by the optical signal generator is below 1.

[0018] Preferably, the optical signal generator is a single-photon generator.

[0019] Preferably, the optical signal receiver is a single-photon detector.

[0020] Preferably, the OCC codes corresponding to each receiving party are different.

[0021] The beneficial technical effects of the present utility model:

[0022] The present utility model provides a multi-user QKD system based on OCC codes. One-to-many multi-user QKD communication is achieved by using OCC codes (optical orthogonal codes), which can preferably reduce the crosstalk between multi-access information, maximize the improvement of multi-user capacity, use the same frequency band in the same channel for QKD communication by using OCC codes and code division multiplexing technology, and has the advantages of high spectrum utilization rate, large system capacity, strong anti-interference ability, etc., does not occupy too many channel resources, and the system structure is simple and has scalability. Brief Description of the Drawings

[0023] Figure 1 is the overall structural block diagram of the present utility model;

[0024] Wherein: 101, optical signal generator; 102, OCC code generator; 103, modulator; 104, quantum random number generator; 201, optical signal receiver; 202, demodulator; 301, coupler. Detailed Embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below in conjunction with embodiments. However, the scope of protection required by the present utility model is not limited to the following specific embodiments.

[0026] Embodiment 1

[0027] As Figure 1 shown, a multi-user QKD system based on OCC codes includes a sender and multiple receivers (Bob1, Bob2, Bob3,..., BobN);

[0028] The sender includes an optical signal generator 101, an OCC code generator 102 and a modulator 103;

[0029] The receiver includes an optical signal receiver 201 and a demodulator 202;

[0030] The output end of the optical signal generator 101 and one output end of the OCC code generator 102 are respectively connected to different input ends of the modulator 103; the output end of the optical signal receiver 201 is connected to one input end of the demodulator 202; the other output end of the OCC code generator 102 is respectively connected to the other input ends of the demodulators 202 of each receiver; the output end of the modulator 103 is respectively connected to the input ends of the optical signal receivers 201 in each receiver.

[0031] In the specific implementation process, one-to-many multi-user QKD communication is realized by using OCC codes (optical orthogonal codes), which can better reduce the crosstalk between multi-access information, can maximize the multi-user capacity, use the same frequency band in the same channel for QKD communication by using OCC codes and code division multiplexing technology, has the advantages of high spectrum utilization rate, large system capacity, strong anti-interference ability, etc., does not occupy too many channel resources, and the system structure is simple and has scalability.

[0032] More specifically, the sender further includes a quantum random number generator 104;

[0033] The output end of the quantum random number generator 104 is connected to one input end of the modulator 103.

[0034] In the specific implementation process, the optical signal generator 101 of the sender generates an optical pulse sequence, which is modulated by the modulator 103 controlled by the OCC code generator 102 and the quantum random number generator 104, so that the optical pulse sequence has key information and multiplexing information;

[0035] The modulator 103 performs intensity modulation on the optical pulse sequence according to the electrical signal provided by the OCC code generator 102: when the electrical signal is 1, the intensity of the corresponding optical pulse sequence is not operated; when the electrical signal is 0, the intensity of the corresponding optical pulse sequence is modulated to 0;

[0036] The modulator 103 performs key information modulation on the optical pulse sequence according to the quantum random number electrical signal provided by the quantum random number generator 104. According to the requirements of the QKD protocol, the optical pulse sequence is modulated in terms of basis vector, phase, polarization, etc. according to the random number signal;

[0037] At the receiver, first, the optical signal receiver 201 decodes the key information of the received optical pulse sequence to obtain a key with code division multiple access information, and then, after demodulation by the demodulator 202, a unique key is obtained.

[0038] More specifically, the OCC codes corresponding to each receiver are different.

[0039] In the specific implementation process, each receiver has its own unique identification code, which is a group of codes in the OCC code sequence. According to the identification code of the receiver to be communicated with, the OCC code generator 102 of the sender generates the corresponding OCC code to ensure that the generated optical pulse sequence can be modulated into having the correct multiplexing information and can be demodulated (demultiplexed) by the correct receiver, while other receivers cannot demodulate (demultiplex) the multiplexing information because they do not have the correct identification code, achieving the effect of code division multiple access and ensuring the secure transmission of data.

[0040] The optical orthogonal code (OCC code) can be expressed by the following formula:

[0041] (F, K, λ a , λ c )

[0042]

[0043] where F is the length, K is the weight, satisfying the autocorrelation and cross-correlation characteristics, and the autocorrelation and cross-correlation constraints are respectively the (0, 1) sequence family of λ a and λ c . K is the number of "1"s in the sequence, F is the length of the sequence, λ a is the maximum value of the sidelobe of the autocorrelation function of any each codeword, λc is the maximum cross-correlation value between any two codewords.

[0044] More specifically, the output end of the modulator 103 is respectively connected to the input end of the optical signal receiver 201 in each receiving party through a quantum channel.

[0045] More specifically, it further includes a coupler 301; the output end of the modulator 103 is connected to the input end of the coupler 301 through a quantum channel, and the output end of the coupler 301 is respectively connected to the input end of the optical signal receiver 201 in each receiving party through a quantum channel.

[0046] More specifically, the average number of photons in the optical pulse sequence generated by the optical signal generator 101 is below 1.

[0047] More specifically, the optical signal generator 101 is a single-photon generator.

[0048] More specifically, the optical signal receiver 201 is a single-photon detector.

[0049] According to the disclosure and teachings of the above specification, those skilled in the art to which the present utility model pertains can also make changes and modifications to the above embodiments. Therefore, the present utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the utility model should also fall within the protection scope of the claims of the present utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience and do not constitute any limitation to the present utility model.

Claims

1. A multi-user QKD system based on OCC codes, characterized in that, It includes a sender and multiple receivers; The sender includes an optical signal generator, an OCC code generator, and a modulator; The receiver includes an optical signal receiver and a demodulator; The output end of the optical signal generator and one output end of the OCC code generator are respectively connected to different input ends of the modulator; the output end of the optical signal receiver is connected to one input end of the demodulator; the other output end of the OCC code generator is respectively connected to the other input ends of the demodulators of each receiver; the output end of the modulator is respectively connected to the input ends of the optical signal receivers in each receiver; The sender further includes a quantum random number generator; The output end of the quantum random number generator is connected to one input end of the modulator; It further includes a coupler; the output end of the modulator is connected to the input end of the coupler through a quantum channel, and the output end of the coupler is respectively connected to the input ends of the optical signal receivers in each receiver through a quantum channel.

2. The multi-user QKD system based on the OCC code according to claim 1, wherein, The average photon number of the optical pulse sequence generated by the optical signal generator is below 1.

3. A multi-user QKD system based on OCC codes according to claim 1, characterized in that, The optical signal generator is a single-photon generator.

4. The multi-user QKD system based on the OCC code according to claim 3, wherein, The optical signal receiver is a single-photon detector.

5. A multi-user QKD system based on OCC code according to claim 1, characterized in that, The OCC codes corresponding to each receiver are different.

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