Optical communication system and method based on amplitude phase two-dimensional chaotic encryption

Abstract

The invention discloses an optical communication system and method based on amplitude phase two-dimensional chaotic encryption, in the system, light of a first laser is coupled with a light text signal through a Mach-Zehnder modulator and an optical coupler and then is divided into two beams, and one beam sequentially passes through a delay line and the like and then enters the Mach-Zehnder modulator; the other beam is injected into the phase modulator; light of a fifth laser is divided into two beams by a third optical coupler, and one beam passes through a reflector; the other beam is divided into two beams through a fourth optical coupler, and one beam is used for channel transmission; and the other beam enters a first phase modulator after passing through a first circulator and the like. The light after channel transmission passes through a circulator and the like and then enters a phase modulator; the other beam is divided into two beams after passing through a phase modulator and an optical coupler, and one beam is connected with an optical mixer; and the other beam sequentially passes through a second delay line and the like and then enters a second Mach-Zehnder modulator. Light of the second laser passes through the second Mach-Zehnder modulator and then enters the optical mixer; and decryption is realized through coherent detection.

Description

Technical Field

[0001] The present invention belongs to the field of optical information technology, and in particular relates to an optical communication system and method based on amplitude-phase dual-dimensional chaotic encryption. Background Art

[0002] Chaotic signals have shown significant advantages in the field of high-speed, long-distance secure communications due to their unique unpredictability, noise-like, wide bandwidth, and extreme sensitivity to initial values. Chaotic encryption communication of plaintext signals is based on the physical layer, and its security is more outstanding than traditional secure communication systems based on application layer digital encryption.

[0003] However, the existing optical chaotic secure communication system still has problems such as weak confidentiality and low information transmission efficiency. To this end, the present invention proposes an optical communication system and method based on amplitude-phase dual-dimensional chaotic encryption. The present invention can increase the transmission rate and expand the key space while allowing plaintext information to participate in the generation of chaotic signals and encrypt them in the dual dimensions of amplitude and phase, effectively improving the security and reliability of the communication system. Summary of the invention

[0004] In view of the above-mentioned status quo of the prior art, the present invention improves the complexity and transmission rate of chaotic signals, and adopts the means of chaotic encryption of plaintext signals in both amplitude and phase dimensions to effectively improve the security and reliability of optical chaotic communication systems. An optical communication system and method based on amplitude and phase dual-dimensional chaotic encryption are designed by combining electro-optical delay intensity feedback and all-optical feedback with light injection.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The optical communication system based on amplitude-phase dual-dimensional chaotic encryption includes a transmitter and a receiver, and the transmitter and the receiver are connected through an optical fiber link, as follows:

[0007] At the transmitting end, the binary plaintext signal is converted into an electrical signal by a mapper and injected into an in-phase quadrature modulator (IQM); the third optical signal emitted by the third continuous wave laser enters the in-phase quadrature modulator, and the electrical signal is modulated into an optical signal by the in-phase quadrature modulator to obtain a plaintext signal for optical chaos encryption, and the optical signal enters the first optical attenuator after passing through the third variable optical attenuator;

[0008] The first optical signal emitted by the first continuous wave laser passes through the first Mach-Zehnder modulator and enters the first optical coupler to be divided into two optical signals, namely, the first optical signal and the second optical signal. The first optical signal is coupled with the plaintext signal and enters the first phase modulator; the second optical signal is coupled with the plaintext information and passes through the first delay line, the first variable optical attenuator, the first photodetector, and the first radio frequency amplifier in sequence and enters the first Mach-Zehnder modulator.

[0009] The fifth continuous wave laser is divided into two beams after passing through the third optical coupler, one beam is projected to the reflector (M), and the other beam is divided into two optical signals through the fourth optical coupler, wherein the first beam enters the first input port of the wavelength division multiplexer (WDM), the second beam enters the sixth continuous wave laser after passing through the first circulator, returns to the first circulator, and then enters the first phase modulator through the third photodetector, the output port of the first phase modulator is connected to the second input port of the wavelength division multiplexer, and the output port of the wavelength division multiplexer is connected to the receiving end through the optical fiber;

[0010] At the receiving end, the signal transmitted through the optical fiber link is divided into two beams by the wavelength division multiplexer, one beam enters the seventh continuous wave laser after passing through the second circulator, then returns to the second circulator, and then enters the second phase modulator through the fourth photodetector, and the other beam enters the second phase modulator;

[0011] The optical signal after phase decryption by the second phase modulator is divided into two beams after passing through the second optical coupler. One beam of light enters the first input port of the 90-degree optical mixer (Hybrid), and the other beam passes through the second delay line, the second variable photoelectric attenuator, the second photodetector, and the second radio frequency amplifier in sequence and then enters the second Mach-Zehnder modulator. The optical signal emitted by the second continuous wave laser enters the second input port of the 90-degree optical mixer after passing through the second Mach-Zehnder modulator.

[0012] Intensity decryption is achieved through subtraction of a 90-degree optical mixer. The 90-degree optical mixer is connected to the first input port of the coherent receiver. The fourth continuous wave laser is connected to the second input port of the coherent receiver. The electrical signal is obtained through the coherent receiver, and then the original binary plaintext information is restored through the inverse mapper.

[0013] In the present invention, the transmitting end includes three modules: signal modulation, intensity chaos encryption and phase chaos encryption. In the signal modulation module, the binary plaintext signal is generated into an electrical signal through a mapper and injected into an in-phase quadrature modulator; the third optical signal emitted by the third continuous wave laser enters the in-phase quadrature modulator, and the electrical signal is modulated into an optical signal by the in-phase quadrature modulator, thereby obtaining a plaintext signal for optical chaos encryption. The optical signal enters the first optical coupler after passing through the third variable optical attenuator, and is divided into two beams, one of which participates in the intensity chaos participation process; the other enters the first phase modulator. In the intensity chaos module, the first optical signal emitted by the first continuous wave laser enters the first optical coupler after passing through the first Mach-Zehnder modulator in sequence, and is divided into two beams, one of which is coupled with the optical signal and enters the first phase modulator; the other is coupled with the plaintext information and passes through the first delay line, the first variable optical attenuator, the first photodetector, and the first radio frequency amplifier in sequence, and then enters the radio frequency drive port of the first Mach-Zehnder modulator. In the phase chaos encryption module, the fifth optical signal emitted by the fifth continuous wave laser is first divided into two beams by the third coupler, one beam reflects the light back to the fifth continuous wave laser through a reflector; the other beam is also divided into two beams through the fourth optical coupler. One beam enters the wavelength division multiplexer; the other beam passes through the first circulator, first injected into the sixth continuous wave laser, and then passes through the first circulator and the third photodetector in sequence before entering the RF drive port of the first phase modulator. Finally, the signal encrypted by the first phase modulator enters the wavelength division multiplexer, and the output port of the wavelength division multiplexer is connected to the receiving end through an optical fiber.

[0014] The receiving end adopts an open-loop symmetrical structure with the transmitting end, mainly including a phase chaos decryption module, an intensity chaos decryption module and a signal demodulation module. In the phase chaos decryption module, the multiplexed signal transmitted through the optical fiber link is divided into two beams through a wavelength division multiplexer. One beam passes through the second circulator and is first injected into the seventh continuous wave laser, then passes through the second circulator and the fourth photodetector in sequence and enters the second phase modulator; the other beam enters the second phase modulator. In the intensity decryption module, the optical signal after phase decryption is divided into two beams by the second optical coupler, one beam enters the optical mixer; the other beam passes through the second delay line, the second variable optical attenuator, the second photodetector, and the second radio frequency amplifier in sequence and enters the radio frequency driving port of the second Mach-Zehnder modulator. The optical signal generated by the second continuous wave laser passes through the second Mach-Zehnder modulator, and is modulated by the phase decryption signal to generate an intensity chaos signal, which enters the second input port of the optical mixer. The phase decryption signal and the intensity chaos signal are subtracted through the optical mixer to realize the intensity decryption operation. In the signal demodulation module, the intensity-decrypted signal and the optical signal generated by the fourth continuous wave laser are connected to the coherent receiver and can be restored to the electrical signal, and finally the original binary signal is restored through the inverse mapper.

[0015] As a preferred solution, according to the binary plaintext information to be transmitted, 16QAM optical modulation is used to modulate the signal into an optical QAM signal for optical chaotic encryption and transmission; and the optical text signal is involved in the generation process of the intensity chaotic carrier, which also means that the plaintext information is hidden.

[0016] As a preferred embodiment, the parameters of the corresponding devices between the transmitting end and the receiving end are the same, that is, the parameters of the first laser and the second laser are the same; the parameters of the third laser and the fourth laser are the same; the parameters of the sixth laser and the seventh laser are the same; the parameters of the first Mach-Zehnder modulator and the second Mach-Zehnder modulator are the same; the parameters of the first optical coupler, the second optical coupler, the third optical coupler and the fourth optical coupler are the same, such as the coupling coefficients are all 0.5; the parameters of the first delay line and the second delay line are the same; the parameters of the first variable optical attenuator and the second variable optical attenuator are the same; the parameters of the first photodetector and the second photodetector are the same; the parameters of the third photodetector and the fourth photodetector are the same; the parameters of the first radio frequency amplifier and the second radio frequency amplifier are the same; the parameters of the first phase modulator and the second phase modulator are the same.

[0017] In the present invention, the intensity chaos encryption module at the transmitting end generates a first optical chaotic signal through electro-optical delay feedback, and the optical text signal is coupled into the electro-optical delay feedback loop to participate in the generation of the first optical chaotic signal, thereby realizing the hiding of the optical text signal. The phase chaos encryption module generates a driving chaotic signal through all-optical feedback, and injects the driving chaotic signal into the laser again to generate a more complex transmitting chaotic signal, that is, the second optical chaotic signal, and phase encrypts the intensity encryption signal through the first phase modulator. Then, it is wavelength-division multiplexed with the driving chaotic signal to enter the optical fiber transmission link. At the receiving end, a symmetrical structure is used with the transmitting end to generate a synchronized chaotic signal; and the received encrypted signal is phase-decrypted to induce the generation of a synchronized intensity chaotic signal, and preliminary decryption is achieved through an optical mixer; then, coherent detection is performed to restore the electrical signal, and finally, the binary plaintext information is restored through inverse mapping.

[0018] As a preferred solution, the coupling coefficients of all couplers are 0.5.

[0019] As a preferred solution, the communication system signal transmission rate is 40 Gb / s.

[0020] As a preferred solution, the receiving end realizes the recovery of binary plaintext information through an optical mixer, a coherent receiver and a 16QAM inverse mapper.

[0021] The present invention also discloses an optical communication method based on amplitude-phase dual-dimensional chaotic encryption. Based on the above system, the method has the following specific steps:

[0022] At the transmitting end, the binary plaintext signal is mapped to generate an electrical signal and injected into the in-phase orthogonal modulator; the optical signal emitted by the third continuous wave laser is modulated by in-phase orthogonal modulation to obtain the plaintext signal for optical chaos encryption, and the signal enters the first optical coupler through the third variable optical attenuator to participate in the generation of intensity chaos signal; the optical signal emitted by the first continuous wave laser generates an intensity chaos signal through electro-optical delay feedback, and realizes the intensity encryption of the light text signal; the optical signal emitted by the fifth continuous wave laser generates a driving chaos signal after all-optical feedback, and this signal is injected into the sixth continuous wave laser to generate a phase chaos signal; then the first phase modulator is used to encrypt the intensity encrypted signal again, realizing the encryption of the plaintext signal in two dimensions of intensity and phase. In this process, the plaintext information participates in the generation process of optical intensity chaos, which enhances the complexity of the chaotic signal. And because the electro-optical delay feedback loop adopts an open-loop structure, the system has strong robustness, and the device parameters in each module further expand the key space, improving the security of the chaotic communication system.

[0023] At the receiving end, a structure symmetrical to the transmitting end is used to realize chaotic decryption. First, a phase chaos signal synchronized with the transmitting end is generated, and the phase decryption is completed using the second phase modulator; then it is divided into two beams through the second optical coupler, one beam is used for intensity decryption, and the other beam induces the generation of intensity chaos; then a 90-degree optical mixer is used for phase subtraction to achieve intensity decryption; then the signal is demodulated, and the intensity-decrypted signal and the optical signal generated by the fourth continuous wave laser are first coherently detected, and finally the original binary plaintext signal is restored through inverse mapping.

[0024] At the transmitting end of the present invention, the optical signals emitted by the first continuous wave laser, the fifth continuous wave laser and the sixth continuous wave laser are respectively subjected to electro-optical time delay feedback and all-optical feedback combined with optical injection to generate chaotic signals for intensity encryption and phase encryption respectively. The optical signal emitted by the third continuous wave laser is obtained by an in-phase orthogonal modulator to obtain a light signal for optical chaos encryption, which is successively involved in the generation process of intensity chaos through the third variable optical attenuator and the first optical coupler, and intensity chaos encryption is realized. The phase chaos signal is converted into an electrical signal by the third photodetector, and the intensity encrypted signal is phase modulated by the first phase modulator to realize the phase encryption operation.

[0025] At the receiving end of the present invention, a structure symmetrical to the transmitting end is used to realize chaotic decryption. The seventh continuous wave laser is used to generate a phase chaotic signal synchronized with the transmitting end, and the second phase modulator is used to perform phase decryption on the encrypted signal. The optical signal after phase decryption is divided into two beams by the second optical coupler, one beam is used for intensity decryption, and the other beam is used to generate an intensity chaotic signal synchronized with the transmitting end, and then the intensity decryption operation is realized with the phase decryption signal through a 90-degree optical mixer. Then, the intensity decrypted signal and the optical signal generated by the fourth continuous wave laser are coherently detected and restored to an electrical signal, and finally the original binary signal is restored by inverse mapping.

[0026] Preferably, the transmission rate of the signal is set to 40 Gb / s.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The optical communication system and method based on amplitude-phase dual-dimensional chaotic encryption of the present invention, at the transmitting end, firstly, the binary plaintext information is modulated into an optical signal by using an in-phase orthogonal modulator. Chaos is generated by a Mach-Zehnder modulator, and the optical signal is involved in the generation process of the intensity chaotic signal through a coupler to complete the intensity encryption. By allowing the plaintext information to participate in the generation of chaos, not only the complexity of the chaotic signal is improved, but also the hiding of the plaintext information is effectively realized, the security of information transmission is further improved, and the signal is effectively prevented from being intercepted. Then, phase encryption is performed, and the chaotic signal is first generated by an all-optical feedback method, and then the generated chaotic signal is injected by light to generate a new chaotic signal. This method can enhance the bandwidth of the chaotic carrier and overcome the problem of limited information transmission rate caused by the limited bandwidth of the chaotic carrier. Finally, the optical signal is converted into an electrical signal by a photodetector, and phase modulation is performed in a phase modulator to achieve phase encryption. This further expands the key space, effectively lowers the brute force attack of illegal eavesdroppers, and further improves the security and reliability of the communication system. In addition, the present invention adopts an open-loop symmetrical structure to achieve chaotic synchronization, which makes the communication system have strong robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 It is a schematic diagram of the architecture of an optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to a preferred embodiment of the present invention.

[0031] Figure 2 This is a constellation diagram of a 16QAM optical signal input at the transmitting end of an optical communication system based on amplitude-phase dual-dimensional chaotic encryption in a preferred embodiment of the present invention.

[0032] Figure 3This is a constellation diagram of a 16QAM optical signal decrypted in an optical communication system based on amplitude-phase dual-dimensional chaotic encryption in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the embodiments of the present invention, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings and other implementation methods can be obtained based on these accompanying drawings without creative work.

[0034] like Figure 1 As shown, this embodiment is an optical communication system based on amplitude-phase dual-dimensional chaotic encryption, including a transmitting end and a receiving end, wherein:

[0035] The transmitting end components include a first continuous wave laser 1-1, a third continuous wave laser 1-3, a fifth continuous wave laser 1-5, a sixth continuous wave laser 1-6, a first Mach-Zehnder modulator 2-1, a first optical coupler 3-1, a third optical coupler 3-3, a fourth optical coupler 3-4, a first delay line 4-1, a first variable attenuator 5-1, a third variable attenuator 5-3, a first photodetector 6-1, a third photodetector 6-3, a first radio frequency amplifier 7-1, a first phase modulator 8-1, a first circulator 9-1, an in-phase quadrature modulator IQM, a reflector M, and a wavelength division multiplexer WDM;

[0036] The receiving end components include a second continuous wave laser 1-2, a fourth continuous wave laser 1-4, a seventh continuous wave laser 1-7, a second Mach-Zehnder modulator 2-2, a second optical coupler 3-2, a second delay line 4-2, a second variable attenuator 5-2, a second photodetector 6-2, a fourth photodetector 6-4, a second RF amplifier 7-2, a second phase modulator 8-2, a second circulator 9-2, a 90-degree optical mixer, a coherent receiver, and a wavelength division multiplexer.

[0037] The transmitting end and the receiving end are connected through a standard single-mode optical fiber 10 , an erbium-doped optical fiber amplifier 11 and a dispersion compensation optical fiber 12 .

[0038] The specific connection methods of the above components are as follows:

[0039] In the transmitting end, the first continuous wave laser 1-1 is connected to the input port of the first Mach-Zehnder modulator 2-1, the output port of the first Mach-Zehnder modulator 2-1 is connected to the first input port of the first optical coupler 3-1, the first output port of the first optical coupler 3-1 is connected to the input port of the first phase modulator 8-1, the second output port of the first optical coupler 3-1 is connected to the first port of the first delay line 4-1, the second port of the first delay line 4-1 is connected to the first port of the first variable optical attenuator 5-1, the second port of the first variable optical attenuator 5-1 is connected to the input port of the first photodetector 6-1, the output port of the first photodetector 6-1 is connected to the input port of the first radio frequency amplifier 7-1, and the output port of the first radio frequency amplifier 7-1 is connected to the radio frequency driving port of the first Mach-Zehnder modulator 2-1.

[0040] The 16QAM mapper is connected to the first input port of the in-phase quadrature modulator, the third continuous wave laser 1-3 is connected to the second input port of the in-phase quadrature modulator, the output port of the in-phase quadrature modulator is connected to the first port of the third variable optical attenuator 5-3, and the second port of the third variable optical attenuator 5-3 is connected to the second input port of the first optical coupler 3-1.

[0041] The fifth continuous wave laser 1-5 is connected to the input port of the third optical coupler 3-3, the first output port of the third optical coupler 3-3 is connected to the reflector and reflected back to the fifth continuous wave laser 1-5, and a driving chaotic signal is generated in an all-optical feedback manner and injected into the third optical coupler 3-3, the second output port of the third optical coupler 3-3 is connected to the input port of the fourth optical coupler 3-4, the first output port of the fourth optical coupler 3-4 is connected to the first input port of the wavelength division multiplexer, the second output port of the fourth optical coupler 3-4 is connected to the first port of the first circulator 9-1, the second port of the first circulator 9-1 is connected to the sixth continuous wave laser 1-6, the third port of the first circulator 9-1 is connected to the input port of the third photodetector 6-3, the output port of the third photodetector 6-3 is connected to the RF driving port of the first phase modulator 8-1, and the output port of the first phase modulator 8-1 is connected to the second input port of the wavelength division multiplexer.

[0042] In the common transmission channel, the output port of the wavelength division multiplexer is connected to the first port of the standard single-mode optical fiber 10, the second port of the standard single-mode optical fiber 10 is connected to the input port of the erbium-doped fiber amplifier 11, the output port of the erbium-doped fiber amplifier 11 is connected to the first port of the dispersion compensating optical fiber 12, and the second port of the dispersion compensating optical fiber 12 is connected to the input port of the wavelength division multiplexer.

[0043] In the receiving end, the first output port of the wavelength division multiplexer is connected to the first port of the second circulator 9-2, the second port of the second circulator 9-2 is connected to the seventh continuous wave laser 1-7, the third port of the second circulator 9-2 is connected to the input port of the fourth photodetector 6-4, and the output port of the fourth photodetector 6-4 is connected to the RF driving port of the second phase modulator 8-2; the second output port of the wavelength division multiplexer is connected to the input port of the second phase modulator 8-2, the output port of the second phase modulator 8-2 is connected to the input port of the second optical coupler 3-2, the first output port of the second optical coupler 3-2 is connected to the first port of the second delay line 4-2, the second port of the second delay line 4-2 is connected to the first port of the second variable photoelectric attenuator 5-2, and the second port of the second variable photoelectric attenuator 5-2 is connected to the second optical coupler 3-2. The input port of the second electrical detector 6-2 is connected, the output port of the second photodetector 6-2 is connected to the input port of the second RF amplifier 7-2, the output port of the second RF amplifier 7-2 is connected to the RF driving port of the second Mach-Zehnder modulator 2-2, the second continuous wave laser 1-2 is connected to the input port of the second Mach-Zehnder modulator 2-2, the output port of the second Mach-Zehnder modulator 2-2 is connected to the second input port of the 90-degree optical mixer, the second output port of the second optical coupler 3-2 is connected to the first input port of the optical mixer, the third output port of the optical mixer is connected to the first input port of the coherent receiver, the fourth continuous wave laser 1-4 is connected to the second input port of the coherent receiver, the coherent receiver outputs a 16QAM electrical signal, and then the original binary plaintext information is restored through the 16QAM inverse mapper.

[0044] In this embodiment, 16QAM optical modulation is used to modulate the binary plaintext information to be transmitted, and the plaintext information is made to participate in the generation of intensity chaos to achieve information hiding.

[0045] In this embodiment, the coupling coefficients of all couplers are 0.5.

[0046] In this embodiment, the parameters of the first continuous wave laser and the second continuous wave laser are the same; the parameters of the third continuous wave laser and the fourth continuous wave laser are the same; the parameters of the sixth continuous wave laser and the seventh continuous wave laser are the same. The parameters of the first Mach-Zehnder modulator and the second Mach-Zehnder modulator are the same. The parameters of the first delay line and the second delay line are the same; and the parameters of the first variable optical attenuator and the second variable optical attenuator are the same. The parameters of the first photodetector and the second photodetector are the same; the parameters of the third photodetector and the fourth photodetector are the same; and the parameters of the first radio frequency amplifier and the second radio frequency amplifier are the same. The parameters of the first phase modulator and the second phase modulator are the same.

[0047] In this embodiment, the transmission rate of the signal is 40 Gb / s.

[0048] In the optical communication system based on amplitude-phase dual-dimensional chaotic encryption disclosed in this embodiment, the principle of signal encryption and decryption is as follows:

[0049] At the transmitting end, the light signal emitted by the third continuous wave laser is modulated in phase and quadrature to obtain the plaintext signal for optical chaos encryption. The signal participates in the generation process of intensity chaos signal after passing through the third variable optical attenuator and the first optical coupler. The light signal emitted by the first continuous wave laser generates intensity chaos signal through electro-optical delay feedback, and realizes the intensity encryption of light text signal. The light signal emitted by the fifth continuous wave laser generates driving chaos signal after all-optical feedback, and injects this signal into the sixth continuous wave laser to generate phase chaos signal. Then the first phase modulator is used to encrypt the intensity encrypted signal again, so as to realize the encryption of the plaintext signal in two dimensions of intensity and phase. In this process, the plaintext information participates in the generation process of optical intensity chaos, which enhances the complexity of chaotic signal. And because the electro-optical delay feedback loop adopts an open-loop structure, the system has strong robustness, and the device parameters in each module further expand the key space, which improves the security of the chaotic communication system.

[0050] At the receiving end, a structure symmetrical to the transmitting end is used to achieve chaotic decryption. First, a phase chaos signal synchronized with the transmitting end is generated, and the second phase modulator is used to complete the phase decryption. Then it is divided into two beams through the second optical coupler, one for intensity decryption and the other to induce the generation of intensity chaos. After that, a 90-degree optical mixer is used to perform a subtraction operation to achieve intensity decryption. Then the signal is demodulated, and the intensity-decrypted signal and the optical signal generated by the fourth continuous wave laser are first coherently detected. The parameters of this laser are the same as those of the third continuous wave laser at the transmitting end. Finally, the original binary plaintext signal is restored through 16QAM inverse mapping.

[0051] The process of realizing communication in the optical communication system based on amplitude-phase dual-dimensional chaotic encryption in this embodiment is briefly described as follows:

[0052] 1. Set parameters to generate intensity chaotic signals by coupling optical information through electro-optical time delay feedback, and generate phase chaotic signals by combining all-optical feedback with optical injection to further enhance the complexity of chaotic signals.

[0053] 2. The light signal participates in the generation process of the intensity chaotic signal to achieve intensity encryption. The phase chaotic signal is converted into an electrical signal through a photodetector, and the phase encryption of the intensity encrypted signal is achieved through a phase modulator.

[0054] 3. The receiving end adopts a symmetrical structure with the transmitting end. The encrypted signal carrying plaintext information is first phase-decrypted by a synchronized phase chaotic signal. Then, the phase-decrypted signal and the synchronized intensity chaotic signal are intensity-decrypted by an optical mixer. Finally, the transmitted binary plaintext information can be obtained through a coherent receiver and 16QAM inverse mapping.

[0055] The above embodiment is demonstrated by taking the chaotic encryption after optical 16QAM signal modulation of binary plaintext information as an example. However, the present invention is not limited to this single signal format, and can also play an excellent protection role for other signals with amplitude and phase information, such as orthogonal phase shift keying (QPSK) signals.

[0056] The above are preferred implementations of the present invention, and do not limit the protection scope of the present invention. For ordinary technicians in this field, according to the research ideas provided by the present invention, there will be improvements in the specific design scheme, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. An optical communication system based on amplitude-phase dual-dimensional chaotic encryption, including a transmitting end and a receiving end, characterized in that: At the transmitting end, the binary plaintext signal is converted into an electrical signal through a mapper and injected into an in-phase quadrature modulator; the third optical signal emitted by the third continuous wave laser (1-3) enters the in-phase quadrature modulator, and the electrical signal is modulated into an optical signal through the in-phase quadrature modulator to obtain a plaintext signal for optical chaos encryption, and the optical signal enters the first optical attenuator (3-1) after passing through the third variable optical attenuator (5-3); A first optical signal emitted by a first continuous wave laser (1-1) passes through a first Mach-Zehnder modulator (2-1) and then enters a first optical coupler (3-1) to be divided into two optical signals, namely, a first optical signal and a second optical signal; the first optical signal is coupled with a plaintext signal and then enters a first phase modulator (8-1); the second optical signal is coupled with the plaintext signal and then passes through a first delay line (4-1), a first variable optical attenuator (5-1), a first photodetector (6-1), and a first radio frequency amplifier (7-1) in sequence and then enters the first Mach-Zehnder modulator (2-1); The fifth continuous wave laser (1-5) is divided into two beams after passing through the third optical coupler (3-3), one beam is projected onto the reflector, and the other beam is divided into two optical signals through the fourth optical coupler (3-4), wherein the first beam enters the first input port of the wavelength division multiplexer, the second beam enters the sixth continuous wave laser (1-6) after passing through the first circulator (9-1), returns to the first circulator (9-1), and then enters the first phase modulator (8-1) through the third photodetector (6-3), the output port of the first phase modulator (8-1) is connected to the second input port of the wavelength division multiplexer, and the output port of the wavelength division multiplexer is connected to the receiving end through the optical fiber; At the receiving end, the signal transmitted through the optical fiber link is divided into two beams by the wavelength division multiplexer, one beam passes through the second circulator (9-2) and enters the seventh continuous wave laser (1-7), then returns to the second circulator (9-2), and then enters the second phase modulator (8-2) through the fourth photodetector (6-4), and the other beam enters the second phase modulator (8-2); The optical signal after phase decryption by the second phase modulator (8-2) is divided into two beams after passing through the second optical coupler (3-2), one beam of light enters the first input port of the 90-degree optical mixer, and the other beam of light passes through the second delay line (4-2), the second variable photoelectric attenuator (5-2), the second photodetector (6-2), and the second radio frequency amplifier (7-2) in sequence before entering the second Mach-Zehnder modulator (2-2), and the optical signal emitted by the second continuous wave laser (1-2) passes through the second Mach-Zehnder modulator (2-2) before entering the second input port of the 90-degree optical mixer; Intensity decryption is achieved through subtraction of a 90-degree optical mixer, the 90-degree optical mixer is connected to a first input port of a coherent receiver, a fourth continuous wave laser (1-4) is connected to a second input port of the coherent receiver, an electrical signal is obtained through the coherent receiver, and then the original binary plaintext information is restored through an inverse mapper.

2. According to claim 1, the optical communication system based on amplitude-phase dual-dimensional chaotic encryption is characterized in that: The parameters of the first continuous wave laser and the second continuous wave laser are the same; the parameters of the third continuous wave laser and the fourth continuous wave laser are the same; and the parameters of the sixth continuous wave laser and the seventh continuous wave laser are the same.

3. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to claim 1 is characterized in that: The parameters of the first Mach-Zehnder modulator and the second Mach-Zehnder modulator are the same.

4. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to claim 1 is characterized in that: The coupling coefficients of the first optical coupler, the second optical coupler, the third optical coupler, and the fourth optical coupler are all 0.

5.

5. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to claim 1 is characterized in that: The output port of the wavelength division multiplexer is connected to the receiving end through a standard single-mode optical fiber (10), an erbium-doped optical fiber amplifier (11) and a dispersion compensation optical fiber (12) in sequence.

6. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to claim 1 is characterized in that: The parameters of the first delay line and the second delay line are the same; and the parameters of the first variable optical attenuator and the second variable optical attenuator are the same.

7. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to claim 1 is characterized in that: The first photodetector and the second photodetector have the same parameters; the third photodetector and the fourth photodetector have the same parameters; and the first radio frequency amplifier and the second radio frequency amplifier have the same parameters.

8. The optical communication system based on amplitude-phase dual-dimensional chaotic encryption according to any one of claims 1 to 7, characterized in that: The parameters of the first phase modulator and the second phase modulator are the same.

9. An optical communication method based on amplitude-phase dual-dimensional chaotic encryption, based on a system as claimed in any one of claims 1 to 8, characterized in that: The specific steps of the method are as follows: At the transmitting end, the binary plaintext signal is generated into an electrical signal through a mapper and injected into an in-phase orthogonal modulator; the optical signal emitted by the third continuous wave laser (1-3) is subjected to in-phase orthogonal modulation to obtain a plaintext signal for optical chaos encryption, and the signal enters the first optical coupler (3-1) through a third variable optical attenuator (5-3) to participate in the generation of an intensity chaos signal; the optical signal emitted by the first continuous wave laser (1-1) is fed back through an electro-optical time delay to generate an intensity chaos signal, and intensity encryption of the optical plaintext signal is achieved; The optical signal emitted by the fifth continuous wave laser (1-5) generates a driving chaotic signal after all-optical feedback, and the signal is injected into the sixth continuous wave laser (1-6) to generate a phase chaotic signal; then the first phase modulator (8-1) is used to perform phase encryption on the intensity-encrypted signal again, thereby realizing encryption of the plaintext signal in two dimensions, namely, intensity and phase; At the receiving end, a phase chaos signal synchronized with the transmitting end is generated, and phase decryption is completed using a second phase modulator (8-2); then, the signal is divided into two beams through a second optical coupler (3-2), one beam is used for intensity decryption, and the other beam induces the generation of intensity chaos; then, a subtraction operation is performed through a 90-degree optical mixer to achieve intensity decryption; then, signal demodulation is performed, firstly, the intensity-decrypted signal and the optical signal generated by the fourth continuous wave laser (1-4) are coherently detected, and finally, the original binary plaintext signal is restored through inverse mapping.

10. The optical communication method based on amplitude-phase dual-dimensional chaotic encryption according to claim 9 is characterized in that: The signal transmission rate is 40Gb / s.

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