High-capacity chaotic confidential transmission device based on few-mode fiber

Abstract

The invention belongs to the technical field of chaotic secret communication, and discloses a high-capacity chaotic secret transmission device based on a few-mode optical fiber, which comprises a driving source, the few-mode optical fiber, a communication party A and a communication party B. The communication party A comprises a party A chaotic laser, N signal generators, N combiners and a mode division multiplexer, the communication side B comprises a side B chaotic laser, N signal receivers, N subtracters and a modular decomposition multiplexer; a signal output by the driving source is divided into two beams of first injection light and second injection light after passing through the first beam splitter, and the two beams of first injection light and second injection light are respectively injected into the A-side chaotic laser and the B-side chaotic laser to be in chaotic synchronization with the driving source; synchronous transmission of multi-mode chaotic carrier confidential signals is realized by using the few-mode optical fiber, and the transmission capacity of the chaotic confidential transmission device is greatly improved.

Description

Technical Field

[0001] The present invention relates to a high-capacity chaotic secure transmission device based on few-mode fiber, belonging to the technical field of chaotic secure communication in the field of communication. Background Art

[0002] With the rapid development of today's information network and the rapid increase in information transmission rate, the information security problems brought about are becoming increasingly prominent. The security of traditional secure communication systems depends on mathematical encryption algorithms at the application layer. With the improvement of computing power (especially quantum computing), there is always a possibility of being cracked in principle for algorithm encryption. Therefore, chaotic secure communication, as a physical layer hardware encryption technology, has attracted much attention due to its security advantages. Chaotic secure communication focuses on research such as rate improvement and security enhancement. Among them, improving the chaotic secure transmission capacity is one of the research concerns.

[0003] Methods for improving the chaotic secure transmission capacity include wavelength division multiplexing, polarization multiplexing, space division multiplexing, etc. In 2004, Professor T. Matsuura of Takushoku University in Japan and others proposed theoretically and experimentally to improve the chaotic secure transmission capacity by using wavelength division multiplexing (Optics Letters, 29(23):2731-2733, 2004). In 2012, Professor Jiang Ning and others experimentally realized the chaotic secure transmission of two on-off keying (OOK) signals by using two orthogonal polarization modes of a vertical cavity surface emitting chaotic laser, and its overall transmission capacity reached 10 Gbit / s (IEEE Photonics Technology Letters, 24(13):1094-1096, 2012). In 2015, the team of Professor Yin Hongxi of Dalian University of Technology used polarization multiplexing of distributed feedback semiconductor lasers to experimentally realize the chaotic secure transmission of OOK signals with a capacity of 2×1.25 Gbit / s (Applied Optics, 54(14):4509-4513, 2015). In 2016, Professor Jiang Ning and others used five-channel wavelength division multiplexing of a multimode semiconductor laser to theoretically obtain the two-way chaotic secure transmission of OOK signals with an overall capacity of 15 Gbit / s (Nonlinear Dynamics, 86(3):1937-1949, 2016). In 2023, the team of Professor Wang Jian of Huazhong University of Science and Technology used space division multiplexing of seven-core fiber to experimentally realize the chaotic secure transmission of OOK signals with a capacity of 7×10 Gbit / s and orthogonal phase shift keying (QPSK) signals with a capacity of 7×20 Gbit / s (Optics Letters, 48(17):4440-4443, 2023).

[0004] At present, the chaotic secure transmission capacity has reached more than 100 Gbit / s, but it still cannot meet the requirement of the next-generation new multi-dimensional multiplexing high-speed coherent optical access system with a capacity exceeding 200 Gbit / s. Summary of the Invention

[0005] To solve the technical problem of insufficient transmission capacity in chaotic secure communication in the prior art, the present invention proposes a high-capacity chaotic secure transmission device based on few-mode fiber. By combining few-mode fiber multiplexing with 16QAM high-order signal modulation, the chaotic secure transmission capacity is increased to 200 Gbit / s, providing a solution for improving the chaotic secure transmission capacity.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is: a high-capacity chaotic secure transmission device based on few-mode fiber, including: a driving source, a few-mode fiber, Party A of communication and Party B of communication.

[0007] Party A of communication includes a chaotic laser of Party A, N signal generators, N combiners and a mode division multiplexer. Party B of communication includes a chaotic laser of Party B, N signal receivers, N subtractors and a mode division demultiplexer; where N is a positive integer.

[0008] The signal output by the driving source is divided into two beams, namely the first injection light and the second injection light, after passing through the first beam splitter. The first injection light is used to inject into the chaotic laser of Party A to generate chaotic laser.

[0009] The signal to be transmitted is encoded into 16QAM signals by each signal generator; the chaotic laser output by the chaotic laser of Party A is divided into N beams after passing through the second beam splitter. Each beam of chaotic laser and a 16QAM signal emitted by a signal generator are output as chaotic carrier encrypted signals after passing through a combiner. Each chaotic carrier encrypted signal and the second injection light are connected to the mode division multiplexer, and after being matched with each mode of the few-mode fiber through the mode division multiplexer, they are transmitted through the few-mode fiber to the mode division demultiplexer. The mode division demultiplexer is used to separate each chaotic carrier encrypted signal and the second injection light. The separated second injection light is injected into the chaotic laser of Party B to synchronize chaotically with the driving source. Each of the separated chaotic carrier encrypted signals is respectively connected to the first input end of a subtractor; the chaotic signal output by the chaotic laser of Party B is divided into multiple beams after passing through the third beam splitter and is respectively sent to the second input end of a subtractor to decrypt each chaotic carrier encrypted signal to obtain a carrier signal, and the carrier signal is received by the signal receiver for signal restoration.

[0010] The value of N is 3 to 8.

[0011] The value of N is 5.

[0012] The driving source includes a distributed feedback laser, an optical fiber coupler, a first variable optical attenuator, and a first optical fiber mirror. The output end of the distributed feedback laser is connected to the input end of the optical fiber coupler. The light output from the first output end of the optical fiber coupler is incident on the first optical fiber mirror after passing through the first variable optical attenuator, and then is reflected by the first optical fiber mirror and returns to the distributed feedback laser along the original path to make it output chaotic laser. The output chaotic laser is output from the second output end of the optical fiber coupler.

[0013] The driving source further includes an erbium-doped fiber amplifier and an isolator. The chaotic laser output from the second output end of the optical fiber coupler is amplified by the erbium-doped fiber amplifier and isolated by the isolator, and then sent to the first beam splitter.

[0014] The Party A chaotic laser includes a Party A distributed feedback laser, a second variable optical attenuator, and a second optical fiber mirror. The output end of the Party A distributed feedback laser is connected to the input end of the second beam splitter. The light output from the first output end of the second beam splitter is incident on the second optical fiber mirror after passing through the second variable optical attenuator, and then is reflected by the second optical fiber mirror and returns to the Party A distributed feedback laser along the original path to make it output chaotic laser. The output chaotic laser is divided into multiple beams by the second beam splitter and output from its respective second output ends.

[0015] The first injection light is injected into the Party A distributed feedback laser through the second beam splitter.

[0016] The Party B chaotic laser includes a Party B distributed feedback laser, a third variable optical attenuator, and a third optical fiber mirror. The output end of the Party B distributed feedback laser is connected to the input end of the second beam splitter. The light output from the first output end of the third beam splitter is incident on the second optical fiber mirror after passing through the third variable optical attenuator, and then is reflected by the third optical fiber mirror and returns to the Party B distributed feedback laser along the original path to make it output chaotic laser. The output chaotic laser is divided into multiple beams by the third beam splitter and output from its respective second output ends.

[0017] The second injection light is injected into the Party B distributed feedback laser through the third beam splitter.

[0018] Each signal generator is used to generate 16QAM signals at 40 Gbit / s.

[0019] The working principle of the present invention is as follows: When the few-mode fiber transmits messages, through mode multiplexing and demultiplexing, each mode can independently transmit information, doubling the capacity of the channel. Compared with single-mode fiber, the few-mode fiber can significantly improve the chaotic secure transmission capacity. Compared with multi-core fiber, the few-mode fiber has the same cladding diameter as the single-mode fiber and has good compatibility with the single-mode fiber system.

[0020] The present invention has the following beneficial effects compared with the prior art:

[0021] The present invention provides a device for improving the chaotic secure transmission capacity by using few-mode fiber. By combining few-mode fiber multiplexing with 16QAM high-order signal modulation, the capacity of chaotic secure communication is effectively improved, and the chaotic secure transmission capacity is increased to 200 Gbit / s, providing a solution for improving the chaotic secure transmission capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a device for improving the chaotic secure transmission capacity by using few-mode fiber provided in Embodiment 1 of the present invention;

[0023] Figure 2 It is a 40 Gbit / s quadrature amplitude modulation (16QAM) signal transmitted when the present invention encrypts and decrypts information; Figure 2 In (a), it is a time waveform diagram of the 16QAM signal, the horizontal axis is time, and the vertical axis is the signal amplitude of the I channel and the Q channel; (b) is a constellation diagram of the 16QAM signal, the horizontal axis is the carrier signal of the I channel, and the vertical axis is the carrier signal of the Q channel;

[0024] Figure 3 It is a schematic diagram of a device for improving the chaotic secure transmission capacity by using few-mode fiber provided in Embodiment 2 of the present invention.

[0025] In the figure: 1a - distributed feedback laser; 2a - fiber coupler; 3a - first variable optical attenuator; 4a - first fiber mirror; 5 - erbium-doped fiber amplifier; 6 - optical isolator; 7 - first beam splitter; 8 - mode division multiplexer; 9 - few-mode fiber; 10 - mode de-multiplexer; 1b - distributed feedback laser of Party A; 2b - second beam splitter; 3b - second variable optical attenuator; 4b - second fiber mirror; 5b - combiner; 6b - signal generator; 1c - distributed feedback laser of Party B; 2c - third beam splitter; 3c - third variable optical attenuator; 4c - third fiber mirror; 5c - subtractor; 6c - signal receiver. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, 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. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1

[0028] As Figure 1As shown in the figure, Embodiment 1 of the present invention provides a high-capacity chaotic secure transmission device based on a few-mode fiber, including: a driving source, a few-mode fiber 9, a communication Party A and a communication Party B;

[0029] The communication Party A includes an A-party chaotic laser, N signal generators 6b, N combiners 5b, and a mode division multiplexer 8, and the communication Party B includes a B-party chaotic laser, N signal receivers 6c, N subtractors 5c, and a mode demultiplexer 10; where N is a positive integer;

[0030] The signal output by the driving source is divided into two beams, namely a first injection light and a second injection light, by a first beam splitter 7, wherein the first injection light is used to inject into the A-party chaotic laser to generate chaotic laser;

[0031] The signal to be transmitted is encoded into 16QAM signals by each signal generator 6b; the chaotic laser output by the A-party chaotic laser is divided into N beams by a second beam splitter 2b, and each beam of chaotic laser and a 16QAM signal sent by a signal generator 6b are output as chaotic carrier encrypted signals after passing through a combiner 5b. Each chaotic carrier encrypted signal and the second injection light are connected to the mode division multiplexer 8, and after being matched with each mode of the few-mode fiber 9 through the mode division multiplexer 8, they are transmitted to the mode demultiplexer 10 through the few-mode fiber 9. The mode demultiplexer 10 is used to separate each chaotic carrier encrypted signal and the second injection light. The separated second injection light is injected into the B-party chaotic laser to make it chaotic synchronous with the A-party chaotic laser, and each separated chaotic carrier encrypted signal is respectively connected to a first input end of a subtractor 5c; the chaotic signal output by the B-party chaotic laser is divided into multiple beams by a third beam splitter 2c and then respectively sent to a second input end of a subtractor 5c to decrypt each chaotic carrier encrypted signal to obtain a carrier signal, and the carrier signal is restored by the signal receiver 6c.

[0032] Specifically, in this embodiment, the value of N is 5.

[0033] The working principle of this embodiment is as follows: The signal output by the driving source is divided into two beams, namely a first injection light and a second injection light, by a first beam splitter 7. The first injection light is used to inject into the A-party chaotic laser to generate chaotic laser, and the second injection light is injected into the B-party chaotic laser through the mode division multiplexer 8, the few-mode fiber 9, and the mode demultiplexer 10 to make it chaotic synchronous with the A-party chaotic laser, thus realizing the chaotic synchronization of the communication between Party A and Party B. The signal generator 6b generates as Figure 2The 40 Gbit / s 16QAM information shown is coupled with the chaotic laser output from the chaotic laser of Party A through the multiplexer 5b. The coupled chaotic carrier encrypted signal is divided into 5 paths, and then multiplexed with the second injection light into each mode of at least the few-mode fiber 9 through the mode division multiplexer 8, and then demultiplexed by the mode de-multiplexer 10 to obtain 5 paths of chaotic carrier encrypted signals and the second injection light. Then, after the 5 paths of chaotic carrier encrypted signals are demodulated by the synchronous chaotic signal output from the chaotic laser of Party B, the original 5 paths of 16QAM information can be restored. Therefore, since the few-mode fiber is a fiber that can simultaneously transmit multiple-mode optical signals, and each mode can be used as an independent channel to transmit information, the parallel transmission through the few-mode fiber in the present invention can improve the chaotic secure transmission capacity.

[0034] In addition, in this embodiment, the value range of N can also be 3 to 8. Then, the few-mode fiber can realize the synchronous transmission of 3 to 8 paths of 16QAM information, and the mode division multiplexer 8 and the mode de-multiplexer 10 can be photon lanterns.

[0035] Embodiment 2

[0036] As Figure 3 shown, Embodiment 2 of the present invention provides a high-capacity chaotic secure transmission device based on a few-mode fiber. Similar to Embodiment 1, in this embodiment, it includes a driving source, a few-mode fiber 9, a communication Party A and a communication Party B; the communication Party A includes a chaotic laser of Party A, N signal generators 6b, N multiplexers 5b and a mode division multiplexer 8, and the communication Party B includes a chaotic laser of Party B, N signal receivers 6c, N subtractors 5c and a mode de-multiplexer 10.

[0037] Different from Embodiment 1, in this embodiment, the driving source includes a distributed feedback laser 1a, an optical fiber coupler 2a, a first variable optical attenuator 3a, and a first optical fiber mirror 4a. The output end of the distributed feedback laser 1a is connected to the input end of the optical fiber coupler 2a. The light output from the first output end of the optical fiber coupler 2a is incident on the first optical fiber mirror 4a after passing through the first variable optical attenuator 3a, and then returns to the distributed feedback laser 1a along the original path after being reflected by the first optical fiber mirror 4a to make it output chaotic laser, and the output chaotic laser is output from the second output end of the optical fiber coupler 2a.

[0038] Further, in this embodiment, the driving source further includes an erbium-doped fiber amplifier 5 and an isolator 6. The chaotic laser output from the second output end of the optical fiber coupler 2a is amplified by the erbium-doped fiber amplifier 5 and isolated by the isolator 6 and then sent to the first beam splitter 7.

[0039] Further, in this embodiment, the Party A chaotic laser includes a Party A distributed feedback laser 1b, a second variable optical attenuator 3b, and a second fiber optic mirror 4b. The output end of the Party A distributed feedback laser 1b is connected to the input end of a second beam splitter 2b. The light output from the first output end of the second beam splitter 2b is incident on the second fiber optic mirror 4b after passing through the second variable optical attenuator 3b, and then returns along the original path to the Party A distributed feedback laser 1b after being reflected by the second fiber optic mirror 4b, causing it to output chaotic laser. The output chaotic laser is split into multiple beams by the second beam splitter 2b and output from its respective second output ends.

[0040] Specifically, in this embodiment, the first injection light is injected into the Party A distributed feedback laser 1b through the second beam splitter 2b. Taking N = 5 as an example, the second beam splitter 2b is a 1×7 fiber coupler, whose input end is connected to the Party A distributed feedback laser 1b, one output end is connected to the second variable optical attenuator 3b, one output end is connected to the first injection light, and five output ends are respectively connected to a multiplexer 5b. In addition, in this embodiment, a 1×2 fiber coupler can also be provided outside the second beam splitter 2b, in which case the second beam splitter 2b is a 1×6 fiber coupler.

[0041] As Figure 3 shown, in this embodiment, the Party B chaotic laser includes a Party B distributed feedback laser 1c, a third variable optical attenuator 3c, and a third fiber optic mirror 4c. The output end of the Party B distributed feedback laser 1c is connected to the input end of a third beam splitter 2c. The light output from the first output end of the third beam splitter 2c is incident on the third fiber optic mirror 4c after passing through the third variable optical attenuator 3c, and then returns along the original path to the Party B distributed feedback laser 1c after being reflected by the third fiber optic mirror 4c, causing it to output chaotic laser. The output chaotic laser is split into multiple beams by the third beam splitter 2c and output from its respective second output ends.

[0042] Specifically, in this embodiment, the second injection light is injected into the Party B distributed feedback laser 1c through the third beam splitter 2c. Taking N = 5 as an example, the third beam splitter 2c is a 1×7 fiber coupler, whose input end is connected to the Party B distributed feedback laser 1c, one output end is connected to the third variable optical attenuator 3c, one output end is connected to the corresponding channel of the second injection light of the mode demultiplexer 10, and five output ends are respectively connected to a subtractor 5c. In addition, in this embodiment, a 1×2 fiber coupler can also be provided outside the third beam splitter 2c to realize the injection of the second injection light into the Party B chaotic laser, in which case the third beam splitter 2c is a 1×6 fiber coupler.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-capacity chaotic secure transmission device based on few-mode optical fiber, characterized in that: include: A driving source, a few-mode optical fiber (9), a communication party A and a communication party B, The communication party A includes a chaotic laser of party A, N signal generators (6b), N combiners (5b) and an analog division multiplexer (8), and the communication party B includes a chaotic laser of party B, N signal receivers (6c), N subtractors (5c) and an analog division multiplexer (10); wherein N is a positive integer; The signal output by the driving source is divided into two beams, a first injection light and a second injection light, after passing through a first beam splitter (7), wherein the first injection light is used to inject into the chaotic laser of party A to make it generate chaotic laser; The signal to be sent is encoded into a 16QAM signal by each signal generator (6b); the chaotic laser output by the chaotic laser of party A is divided into N beams after passing through a second beam splitter (2b); each chaotic laser beam and a 16QAM signal emitted by a signal generator (6b) are outputted through a combiner (5b) to form a chaotic carrier encrypted signal; each chaotic carrier encrypted signal and the second injected light are connected to a mode division multiplexer (8), and after being matched with each mode of a few-mode optical fiber (9) through the mode division multiplexer (8), they are transmitted to a mode division multiplexer (10) through the few-mode optical fiber (9) The analog-to-analog multiplexer (10) is used to separate each chaotic carrier encryption signal from the second injection light, and the separated second injection light is injected into the chaotic laser of party B to make it chaotically synchronized with the driving source. The separated chaotic carrier encryption signals are respectively connected to the first input end of a subtractor (5c); the chaotic signal output by the chaotic laser of party B is divided into multiple beams by the third beam splitter (2c), and then respectively sent to the second input end of a subtractor (5c) to decrypt each chaotic carrier encryption signal to obtain a carrier signal, and the carrier signal is received by a signal receiver (6c) to restore the signal.

2. According to claim 1, a high-capacity chaotic secure transmission device based on few-mode optical fiber is characterized in that: The value of N is 3-8.

3. According to claim 1, a high-capacity chaotic secure transmission device based on few-mode optical fiber is characterized in that: The value of N is 5.

4. According to claim 1, a high-capacity chaotic secure transmission device based on few-mode optical fiber is characterized in that: The driving source comprises a distributed feedback laser (1a), a fiber coupler (2a), a first variable optical attenuator (3a), and a first fiber reflector (4a); the output end of the distributed feedback laser (1a) is connected to the input end of the fiber coupler (2a); the light output from the first output end of the fiber coupler (2a) is incident on the first fiber reflector (4a) after passing through the first variable optical attenuator (3a); then, after being reflected by the first fiber reflector (4a), the light returns to the distributed feedback laser (1a) along the original path, so that the distributed feedback laser outputs chaotic laser light; and the output chaotic laser light is output through the second output end of the fiber coupler (2a).

5. A high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 4, characterized in that: The driving source also includes an erbium-doped fiber amplifier (5) and an isolator (6); the chaotic laser output from the second output end of the fiber coupler (2a) is amplified by the erbium-doped fiber amplifier (5), isolated by the isolator (6), and then sent to the first beam splitter (7).

6. The high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 1, characterized in that: The A-side chaotic laser comprises an A-side distributed feedback laser (1b), a second variable optical attenuator (3b), and a second optical fiber reflector (4b); the output end of the A-side distributed feedback laser (1b) is connected to the input end of the second beam splitter (2b); the light output from the first output end of the second beam splitter (2b) is incident on the second optical fiber reflector (4b) after passing through the second variable optical attenuator (3b); then, after being reflected by the second optical fiber reflector (4b), it returns to the A-side distributed feedback laser (1b) along the original path to make it output chaotic laser light; the output chaotic laser light is divided into multiple beams by the second beam splitter (2b) and output from each of its second output ends.

7. The high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 1, characterized in that: The first injected light is injected into the A-side distributed feedback laser (1b) through a second beam splitter (2b).

8. The high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 1, characterized in that: The B-party chaotic laser comprises a B-party distributed feedback laser (1c), a third variable optical attenuator (3c), and a third optical fiber reflector (4c); the output end of the B-party distributed feedback laser (1c) is connected to the input end of the third beam splitter (2c); the light output from the first output end of the third beam splitter (2c) is incident on the third optical fiber reflector (4c) after passing through the third variable optical attenuator (3c); then, after being reflected by the third optical fiber reflector (4c), it returns to the B-party distributed feedback laser (1c) along the original path so that it outputs chaotic laser light; the output chaotic laser light is divided into multiple beams by the third beam splitter (2c) and output from each of its second output ends.

9. The high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 1, characterized in that: The second injected light is injected into the B-side distributed feedback laser (1c) through a third beam splitter (2c).

10. The high-capacity chaotic secure transmission device based on few-mode optical fiber according to claim 1, characterized in that: Each signal generator (6b) is used to send out a 40Gbit / s 16QAM signal.

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