A photon terahertz security communication and perception integrated system based on chaotic signal

Abstract

This invention discloses a terahertz secure communication and sensing integrated system based on chaotic signals, comprising a multi-wavelength coherent light source module, a communication signal module, a chaotic sensing signal module, a terahertz signal transmitting module, a communication signal receiving module, and a sensing signal receiving module. This system utilizes a flexible optical architecture to generate chaotic signals based on the multi-wavelength coherent light source module, the communication signal module, and the chaotic sensing signal module. These chaotic signals are coupled with plaintext optical signals to generate a chaotic communication and sensing integrated signal, simultaneously achieving chaotic encryption. Furthermore, the terahertz signal transmitting module, combined with a flexible heterodyne beat frequency architecture, generates the terahertz chaotic communication and sensing integrated signal, effectively improving the performance of the integrated communication and sensing signal, significantly reducing the design complexity of the terahertz communication and sensing integrated signal and the transmitter complexity, and effectively enhancing the security of the terahertz communication and sensing integrated system.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication and sensing technology, specifically relating to a photonic terahertz secure communication and sensing integrated system based on chaotic signals. Background Technology

[0002] Terahertz sensing integration (ISAC), as a core technology for next-generation wireless networks, holds immense potential in improving spectrum efficiency and enabling multifunctional applications. However, the open nature of terahertz wireless channels exposes them to severe security threats, such as interference. These threats not only jeopardize data integrity but may also compromise the reliability of sensing results. Therefore, addressing these security vulnerabilities is crucial for ensuring the robustness and reliability of ISAC technology in terahertz wireless networks.

[0003] While traditional cryptographic methods based on mathematical complexity offer robust data protection for terahertz ISAC security, their high computational latency is a major limitation. With the continuous development of large-scale computing power, the security of these methods faces increasingly severe challenges. However, Physical Layer Security (PLS) mechanisms utilize the physical layer entropy characteristics of wireless channels and the inherent randomness of signal processing as physical keys to construct a more secure architecture. In recent years, PLS methods such as artificial noise injection and adaptive beamforming have been theoretically optimized and have shown the potential to enhance ISAC security. However, these methods typically require the allocation of dedicated resources (such as power or spatial degrees of freedom), which may conflict with the efficiency goals of ISAC systems.

[0004] Against this backdrop, chaotic signals, which combine nonlinear dynamics, inherent randomness, wide spectral density, and excellent autocorrelation properties, offer a new approach to resolving the aforementioned contradictions. These signals naturally meet the dual requirements of terahertz secure ISAC systems, enhancing both security and functionality. Their unique chaotic masking mechanism can organically combine low-power communication signals with high-power physical chaos, providing a highly promising solution for realizing terahertz secure ISAC systems.

[0005] A literature search revealed extensive research on secure ISAC waveforms. In 2023, Fuwang Dong et al. from Southern University of Science and Technology of China published a paper titled "Secure ISAC Transmission With Random Signaling" at the IEEE Globecom 2023 conference. This paper derived, designed, and optimized the ISAC waveform to meet the requirements of specific application scenarios, namely, enabling the base station to sense targets of interest while communicating with legitimate users, and simultaneously preventing information leakage to eavesdroppers. However, most of this research remains at the theoretical design and optimization stage and has not yet been systematically experimentally verified.

[0006] Research on the integration of chaotic security and sensing has been conducted for many years. In 2014, Jingjing Zhao et al. from the National University of Defense Technology of China published an article entitled "A chaos-based phase-coded OFDM signal for joint radar-communication systems" at the ICSP2014 conference. This paper implemented phase coding of OFDM signals based on chaos theory, optimized the performance of communication sensing waveforms, and realized a sensing-integrated function centered on sensing optimization. However, this type of coding-based chaotic communication-sensing integration has limitations in terms of mathematical complexity and security.

[0007] In 2023, Bo Yang et al. from Hangzhou Dianzi University in China published an article in Optics Communications entitled "Joint radar and communication system based on a chaotic optoelectronic oscillator." This paper utilizes the electro-optical feedback mechanism of the MZM (Multi-Zoom Oscillator) to generate optical chaos and uses the generated chaotic optical signal as a chaotic carrier for modulation. This signal is then radiated into free space through an antenna, achieving both communication and sensing functions. The experiment ultimately achieved target detection with a resolution of 7 cm and a communication transmission rate of 125 Mbit / s. However, due to limitations in transmission frequency and the inductive coupling mechanism, the security sensing performance achieved by this scheme is restricted. Enhancing sensing performance and improving system security remains a pressing issue. Summary of the Invention

[0008] In view of the above, the purpose of this invention is to provide a photonic terahertz secure communication and sensing integrated system based on chaotic signals. This system utilizes a flexible optical architecture to generate chaotic signals, which are then coupled with plaintext optical signals to generate an integrated optical chaotic communication and sensing signal, simultaneously achieving chaotic encryption. Combined with a flexible heterodyne beat frequency architecture, the system generates the terahertz chaotic communication and sensing integrated signal, effectively improving the performance of the integrated sensing signal, significantly reducing the design complexity and transmitter complexity of the terahertz communication and sensing integrated signal, and effectively enhancing the security of the terahertz communication and sensing integrated system.

[0009] To achieve the above-mentioned objectives, the embodiments provide a photonic terahertz secure communication and sensing integrated system based on chaotic signals, including a multi-wavelength coherent light source module, a communication signal module, a chaotic sensing signal module, a terahertz signal transmitting module, a communication signal receiving module, and a sensing signal receiving module; The multi-wavelength coherent light source module is used to generate two coherent optical carrier signals; The communication signal module is used to modulate the plaintext radio frequency signal to be encrypted onto a beam of optical carrier signal; The chaotic sensing signal module is used to generate chaotic signals and mix them with the communication plaintext radio frequency signals on the optical carrier to generate an integrated chaotic communication and sensing optical chaotic communication and sensing signal, while realizing chaotic masking encryption. The terahertz signal transmitting module is used to convert a chaotic communication and sensing integrated signal into a terahertz chaotic communication and sensing integrated signal based on another optical carrier signal and then transmit it. The communication signal receiving module is used to receive the integrated terahertz chaotic communication and sensing signal and decrypt and demodulate to recover the plaintext communication information. The sensing signal receiving module is used to receive the reflected signal of the terahertz chaotic communication sensing integrated signal acting on the target object and process it to obtain sensing information.

[0010] Preferably, the multi-wavelength coherent light source module uses an electro-optic modulator or electro-optic cavity to generate an optical frequency comb, and uses a filter to filter out two optical carriers from the optical frequency comb. The frequency difference between the two optical carriers is equal to the terahertz frequency. The filter includes a passive filter or an active filter.

[0011] Preferably, the communication signal module includes an optical amplifier 1, an optical coupler 1, a polarization controller 1, a polarization controller 2, a random signal generator, an electrical amplifier 1, an electro-optic modulator, an adjustable attenuator 1, and a polarization controller 3; The optical amplifier 1 is used to amplify a beam of optical carrier signal generated by the multi-wavelength coherent light source module; The optical coupler 1 is used to split the amplified optical carrier information into two beams. One beam is injected into the chaotic sensing signal module after the polarization state is adjusted by the polarization controller 2, and the other beam is input to the electro-optic modulator after the polarization state is adjusted by the polarization controller 1. The random signal generator is used to generate a plaintext radio frequency signal to be encrypted. The plaintext radio frequency signal is amplified by an amplifier 1 and then input into an electro-optic modulator. The electro-optic modulator is used to modulate the input optical carrier signal and modulate the plaintext radio frequency signal to be encrypted onto the optical carrier signal; The adjustable attenuator 1 is used to adjust the optical power of the communication plaintext radio frequency signal on the optical carrier, adjust the ratio used for coupling with the chaotic signal and output to the polarization controller 3; The polarization controller 3 is used to adjust the polarization state of the input signal so as to couple it with the chaotic signal and output it to the chaotic sensing signal module.

[0012] The optical amplifier 1 includes a semiconductor optical amplifier or an erbium-doped fiber amplifier. The electro-optic modulator includes a Mach-Zehnder modulator or a dual parallel Mach-Zehnder modulator.

[0013] Preferably, the chaotic sensing signal module includes a Mach-Zehnder modulator, an optical coupler 2, an optical coupler 3, an optical coupler 4, a photoelectric converter 1, a photoelectric converter 2, a photoelectric converter 3, an optical fiber delay line, an adjustable attenuator 2, and an electrical amplifier 2. The Mach-Zehnder modulator is used to generate broadband optical chaotic signals by self-modulating the plaintext radio frequency signal on the input polarized optical carrier using its own nonlinear photoelectric conversion characteristics. The optical coupler 2 is used to split the bandwidth optical chaotic signal output by the Mach-Zehnder modulator into two beams. One beam of bandwidth optical chaotic signal is input to the photoelectric converter 1 to be converted into an electrical signal for subsequent acquisition. The other beam of bandwidth optical chaotic signal is input to the optical coupler 3 and coupled with the communication plaintext radio frequency signal on the polarized optical carrier to generate an integrated optical chaotic communication and sensing signal, while realizing the chaotic masking and encryption of the communication plaintext radio frequency signal. The optical coupler 4 is used to split the coupled optical chaotic communication sensing integrated signal into two beams. One beam is input to the photoelectric converter 3 to be converted into an electrical signal and used as a reference signal for the sensing receiver for subsequent processing. The other beam is input to the terahertz signal transmitting module to achieve coupling with another optical carrier signal, which is the optical local oscillator signal. The optical fiber delay line is used to introduce a loop delay for the integrated optical chaotic communication and sensing signal generated by the optical coupler 3. The adjustable attenuator 2 is used to adjust the optical power of the optical chaotic syn-inductive integrated signal after the loop delay of the optical fiber delay line feedback to meet the requirements of the photoelectric converter 2. The photoelectric converter 2 is used to convert the integrated optical chaotic communication and sensing signal into an electrical signal in order to achieve modulation of the optical carrier in the signal; The electric amplifier 2 is used to amplify the chaotic inductive integrated electrical signal output by the photoelectric converter 2 to meet the voltage requirements of the nonlinear modulation of the Mach-Zehnder modulator.

[0014] Among them, photoelectric converter 1, photoelectric converter 2 and photoelectric converter 3 all include APD type photoelectric detector, PIN type photoelectric detector or PN type photoelectric detector.

[0015] Preferably, the terahertz signal transmitting module includes an adjustable attenuator 3, an optical coupler 5, an optical amplifier 2, a polarization controller 4, an adjustable attenuator 5, and a terahertz signal transmitter; The adjustable attenuator 3 is used to adjust the optical power of another optical carrier signal, which is the optical local oscillator signal, so that it matches the power of the integrated optical chaotic communication and sensing optical signal output by the chaotic sensing signal module. The optical coupler 5 is used to couple the optical local oscillator signal with the integrated chaotic communication and sensing optical signal. The resulting coupled optical signal is amplified by the optical amplifier 2 and then input to the polarization controller 4. The polarization controller 4 is used to adjust the polarization state of the coupled optical signal to maximize its output optical power, and then input it to the adjustable attenuator 2 for optical power adjustment to maximize the optical power of the optical signal input to the terahertz transmitter. The terahertz signal transmitter is used to generate and radiate a terahertz chaotic communication and sensing integrated signal based on the input optical signal.

[0016] The optical amplifier 2 includes a semiconductor optical amplifier or an erbium-doped fiber amplifier; the terahertz signal transmitter includes a single-row carrier photodetector or a PIN photodetector.

[0017] Preferably, the communication signal receiving module includes a terahertz signal receiver 1 and a communication signal processing module; The terahertz signal receiver 1 is used to receive the integrated terahertz chaotic communication and sensing signal and convert it into an intermediate frequency signal; The communication signal processing module is used to process the intermediate frequency signal, realize down-conversion, chaotic decryption, channel compensation, and recover the plaintext communication information of the transmitting end.

[0018] The terahertz signal receiver 1 includes a subharmonic mixer, a photoconductive antenna, a Schottky barrier diode, or a quantum well photodetector.

[0019] The communication signal processing module utilizes a neural network to achieve chaotic synchronization and thus chaotic decryption. The neural network includes at least one of a fully connected neural network, a convolutional neural network, a recurrent neural network, and a reservoir neural network.

[0020] Preferably, the sensing signal receiving module includes a terahertz signal receiver 2 and a sensing signal processing module; The terahertz signal receiver 2 is used to receive the reflected signal of the terahertz chaotic communication and sensing integrated signal acting on the target object, and convert the reflected signal into an intermediate frequency signal. The sensing signal processing module is used to obtain sensing information by performing signal processing based on the intermediate frequency signal and the reference signal output by the chaotic sensing signal module.

[0021] The terahertz signal receiver 2 includes a subharmonic mixer, a photoconductive antenna, a Schottky barrier diode, or a quantum well photodetector.

[0022] When the sensing signal processing module performs signal processing based on the intermediate frequency signal and combined with the reference signal output by the chaotic sensing signal module, it detects the distance, speed, and two-dimensional or three-dimensional information of the communication signal receiving module and objects between the links through the range-Doppler algorithm, back projection algorithm, or compressed sensing algorithm.

[0023] Compared with the prior art, the beneficial effects of the present invention include at least the following: (1) The present invention realizes a photonic terahertz secure communication and sensing integrated system based on chaotic signals. It utilizes photogenerated physical chaotic signals to realize chaotic masking encrypted communication and sensing, thereby improving the physical layer security of the terahertz communication and sensing integrated system and ensuring the security of terahertz communication and sensing information. (2) Based on chaotic masking, the present invention realizes the fusion of encrypted communication plaintext signal and chaotic signal used for sensing, effectively improving the performance of integrated sensing signal and effectively reducing the design complexity of terahertz chaotic communication sensing integrated signal and transmitter complexity. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the integrated photonic terahertz secure communication and sensing system based on chaotic signals provided in the embodiment. Figure 2This is a schematic diagram of the structure of the multi-wavelength coherent light source module provided in the embodiment. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of this invention.

[0027] The inventive concept of this invention is as follows: Addressing the security threats faced by terahertz communication sensing links, this invention provides a photonic terahertz secure communication sensing integrated system based on chaotic signals. It utilizes a flexible optical architecture to generate chaotic signals, which are coupled with plaintext radio frequency signals to generate an optical chaotic communication sensing integrated signal, simultaneously achieving chaotic encryption. Combined with a flexible heterodyne beat frequency architecture, it realizes the generation of the terahertz chaotic communication sensing integrated signal, effectively improving the performance of the integrated sensing signal, effectively reducing the design complexity of the terahertz communication sensing integrated signal and the transmitter complexity, and effectively improving the security of the terahertz communication sensing integrated system.

[0028] Based on the above inventive concept, such as Figure 1 As shown in the embodiment, the photonic terahertz secure communication and sensing integrated system based on chaotic signals includes a multi-wavelength coherent light source module, a communication signal module, a chaotic sensing signal module, a terahertz signal transmitting module, a communication signal receiving module, and a sensing signal receiving module. The system comprises the following modules: a multi-wavelength coherent light source module to generate two coherent optical carrier signals, which are used for the generation and transmission of a terahertz chaotic communication and sensing integrated signal; a communication signal module to modulate the plaintext radio frequency signal to be encrypted onto one optical carrier signal; a chaotic sensing signal module to generate a chaotic signal and mix it with the plaintext radio frequency signal on the optical carrier to generate a chaotic communication and sensing integrated optical chaotic communication and sensing integrated signal, while simultaneously achieving chaotic masking encryption; a terahertz signal transmission module to convert the chaotic encrypted optical chaotic communication and sensing integrated signal into a terahertz chaotic communication and sensing integrated signal based on another optical carrier signal and then transmit it; a communication signal receiving module to receive the terahertz chaotic communication and sensing integrated signal and decrypt and demodulate it to recover the plaintext communication information; and a sensing signal receiving module to receive the reflected signal of the terahertz chaotic communication and sensing integrated signal acting on the target object and process it to obtain sensing information.

[0029] In this embodiment, the multi-wavelength coherent light source module uses an electro-optic modulator or electro-optic cavity to generate an optical frequency comb. Two optical carrier signals are filtered out from the optical frequency comb using a filter, and the frequency difference between the two optical carrier signals is equal to the terahertz frequency. The filter includes passive filters and active filters. Figure 2As shown, an embodiment provides a multi-wavelength coherent light source module based on an electro-optic modulator, including a tunable laser, a polarization controller, a phase modulator, a radio frequency signal generator, an electrical amplifier, and a tunable wavelength selection switch. The tunable laser generates a seed light signal; the tunable laser can be an external cavity laser, a DFB laser, a DBR laser, or a single-mode solid-state laser, etc. This seed light signal enters the phase modulator after passing through the polarization controller. The phase modulator modulates the phase of the seed light signal. The polarization controller adjusts the polarization state of the seed light signal to maximize the optical power of the output phase modulator. The radio frequency signal generator generates a radio frequency signal, which is amplified by the electrical amplifier and then input to the phase modulator to modulate the phase of the input seed light signal. The tunable wavelength selection switch filters the optical signal and outputs two coherent optical carriers, the frequency difference of which is the frequency at which the terahertz wave is generated.

[0030] In this embodiment, the communication signal module includes an optical amplifier 1, an optical coupler 1, a polarization controller 1, a polarization controller 2, a random signal generator, an electro-amplifier 1, an electro-optic modulator, an adjustable attenuator 1, and a polarization controller 3. The optical amplifier 1 splits an amplified optical carrier signal into two beams. One beam, after polarization adjustment by the polarization controller 2, is injected into the chaotic sensing signal module. The other beam, after polarization adjustment by the polarization controller 1, is input to the electro-optic modulator. The electro-optic modulator modulates the optical carrier signal to be encrypted onto the optical carrier. The polarization controller 1 adjusts the polarization state of the optical carrier input to the electro-optic modulator. The polarization controller 2 adjusts the polarization state of the optical carrier input to the chaotic sensing signal module. The random signal generator generates the plaintext radio frequency signal to be encrypted. The electro-amplifier 1 amplifies the output of the random signal generator. The communication plaintext radio frequency signal to be encrypted; the adjustable attenuator 1 is used to adjust the optical power of the communication plaintext radio frequency signal, adjust the ratio used for coupling with the chaotic sensing signal, and output to the polarization controller 3. This ratio refers to the optical power ratio when the communication plaintext radio frequency signal is coupled with the chaotic signal. The optical power of the chaotic signal and the optical power of the communication plaintext signal can be measured separately by an optical power meter. The adjustable optical attenuator can adjust the optical power of the communication plaintext signal, that is, adjust its optical power when coupled with the chaotic signal, i.e., adjust the coupling ratio; the polarization controller 3 is used to adjust the polarization state of the output signal of the communication signal module to facilitate coupling with the chaotic signal. Specifically, the optical amplifier 1 can be a semiconductor optical amplifier or an erbium-doped fiber amplifier, and the electro-optic modulator can be a Mach-Zehnder modulator or a dual parallel Mach-Zehnder modulator.

[0031] In this embodiment, the chaotic sensing signal module includes a Mach-Zehnder modulator (MZM), optical coupler 2, optical coupler 3, optical coupler 4, photoelectric converter 1, photoelectric converter 2, photoelectric converter 3, fiber delay line, adjustable attenuator 2, and electrical amplifier 2. The MZM utilizes its nonlinear photoelectric conversion characteristics to self-modulate the input polarized optical carrier's plaintext radio frequency signal to generate a broadband optical chaotic signal. Optical coupler 2 splits the broadband optical chaotic signal output from the MZM into two beams: one beam is input to electrical converter 1 to be converted into an electrical signal for subsequent acquisition, and the other beam is input to optical coupler 3 to couple with the polarized optical carrier's plaintext radio frequency signal. Photoelectric converter 1 converts the uncoupled optical chaotic signal into an electrical signal for subsequent acquisition and serves as the target signal for training the neural network. Optical coupler 3 couples the plaintext radio frequency signal with the broadband optical chaotic signal to generate an integrated optical chaotic communication and sensing signal, simultaneously achieving chaotic masking and encryption of the plaintext radio frequency signal. Optical coupler 4 couples the coupled optical chaotic signal... The chaotic communication sensing integrated signal is divided into two beams. One beam is input to the electrical converter 3 to be converted into an electrical signal, serving as a reference signal for the sensing receiver and an input signal for training the neural network. The other beam is input to the optical coupler 5 in the terahertz signal transmitting module to couple with another optical carrier signal, which serves as the optical local oscillator signal. An optical fiber delay line is used to introduce a loop delay for the optical chaotic communication sensing integrated signal generated by the optical coupler 3. An adjustable attenuator 2 is used to adjust the optical power of the optical chaotic sensing integrated signal after the loop delay fed back by the optical fiber delay line to meet the requirements of the photoelectric converter 2. The photoelectric converter 2 is used to convert the optical chaotic communication sensing integrated signal into an electrical signal to achieve modulation of the optical carrier in the signal. An electrical amplifier 2 is used to amplify the chaotic sensing integrated electrical signal output by the photoelectric converter 2 to meet the voltage requirements of MZM nonlinear modulation. Specifically, photoelectric converters 1, 2, and 3 can employ APD-type photodetectors, PIN-type photodetectors, or PN-type photodetectors.

[0032] In this embodiment, the terahertz signal transmitting module includes an adjustable attenuator 3, an optical coupler 5, an optical amplifier 2, a polarization controller 4, and a terahertz signal transmitter. The adjustable attenuator 3 is used to match the power of the optical carrier signal (another optical carrier signal serving as the local oscillator signal) with the power of the integrated optical signal output by the chaotic sensing signal module. The optical coupler 5 is used to couple the local oscillator signal with the integrated optical signal. The optical amplifier 2 amplifies the coupled signal between the integrated optical signal and the local oscillator signal. The polarization controller 4 adjusts the polarization state of the coupled optical signal to maximize its output power. The terahertz signal transmitter generates and radiates the integrated terahertz signal based on the input optical signal. The adjustable attenuator 2 adjusts the polarization of the input optical signal to the terahertz transmitter to maximize the output optical power. Specifically, the optical amplifier 2 can be a semiconductor optical amplifier or an erbium-doped fiber amplifier, and the terahertz signal transmitter can be a single-row carrier photodetector or a PIN photodetector.

[0033] In this embodiment, the communication signal receiving module includes a terahertz signal receiver 1 and a communication signal processing module. The terahertz signal receiver 1 receives the integrated terahertz chaotic communication and sensing signal and converts it into an intermediate frequency (IF) signal. The communication signal processing module processes the IF signal to perform down-conversion, chaotic decryption, channel compensation, and recover the plaintext communication information from the transmitting end. The terahertz signal receiver 1 includes a subharmonic mixer, a photoconductive antenna, a Schottky barrier diode, or a quantum well photodetector.

[0034] In this embodiment, the communication signal processing module utilizes a neural network to achieve chaotic synchronization, thereby enabling chaotic decryption. The neural network has been pre-trained at the transmitting end and shared with the legitimate receiving end. The legitimate receiving end inputs the signal to be decrypted into the pre-trained neural network, and the network output is the synchronized, chaotic optical signal without communication signals. The neural network includes at least one of a fully connected neural network, a convolutional neural network, a recurrent neural network, and a reservoir neural network.

[0035] In this embodiment, the sensing signal receiving module includes a terahertz signal receiver 2 and a sensing signal processing module. The terahertz signal receiver 2 receives the reflected signal from the target object caused by the integrated terahertz chaotic communication and sensing signal, and converts the reflected signal into an intermediate frequency (IF) signal. The sensing signal processing module performs signal processing based on the IF signal and a reference signal output from the chaotic sensing signal module to obtain sensing information. The terahertz signal receiver 1 includes a subharmonic mixer, a photoconductive antenna, a Schottky barrier diode, or a quantum well photodetector.

[0036] In this embodiment, when the sensing signal processing module performs signal processing based on the intermediate frequency signal and in combination with the reference signal output by the chaotic sensing signal module, it detects the distance, speed, and two-dimensional or three-dimensional information of the communication receiving module and objects between the links through the range-Doppler algorithm, the back projection algorithm, or the compressed sensing algorithm.

[0037] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above description is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for integrated sensing and secure communication of photonic terahertz based on chaotic signals, characterized in that, It includes a multi-wavelength coherent light source module, a communication signal module, a chaotic sensing signal module, a terahertz signal transmitting module, a communication signal receiving module, and a sensing signal receiving module; The multi-wavelength coherent light source module is used to generate two coherent optical carrier signals; The communication signal module is used to modulate the plaintext radio frequency signal to be encrypted onto a beam of optical carrier signal; The chaotic sensing signal module is used to generate chaotic signals and mix them with the communication plaintext radio frequency signals on the optical carrier to generate an integrated chaotic communication and sensing optical chaotic communication and sensing signal, while realizing chaotic masking encryption. The terahertz signal transmitting module is used to convert a chaotic communication and sensing integrated signal into a terahertz chaotic communication and sensing integrated signal based on another optical carrier signal and then transmit it. The communication signal receiving module is used to receive the integrated terahertz chaotic communication and sensing signal and decrypt and demodulate to recover the plaintext communication information. The sensing signal receiving module is used to receive the reflected signal of the terahertz chaotic communication sensing integrated signal acting on the target object and process it to obtain sensing information; The chaotic sensing signal module includes a Mach-Zehnder modulator, an optical coupler 2, an optical coupler 3, an optical coupler 4, a photoelectric converter 1, a photoelectric converter 2, a photoelectric converter 3, an optical fiber delay line, an adjustable attenuator 2, and an electrical amplifier 2. The Mach-Zehnder modulator is used to generate broadband optical chaotic signals by self-modulating the plaintext radio frequency signal on the input polarized optical carrier using its own nonlinear photoelectric conversion characteristics. The optical coupler 2 is used to split the bandwidth optical chaotic signal output by the Mach-Zehnder modulator into two beams. One beam of bandwidth optical chaotic signal is input to the photoelectric converter 1 to be converted into an electrical signal for subsequent acquisition. The other beam of bandwidth optical chaotic signal is input to the optical coupler 3 and coupled with the communication plaintext radio frequency signal on the polarized optical carrier to generate an integrated optical chaotic communication and sensing signal, while realizing the chaotic masking and encryption of the communication plaintext radio frequency signal. The optical coupler 4 is used to split the coupled optical chaotic communication sensing integrated signal into two beams. One beam is input to the photoelectric converter 3 to be converted into an electrical signal and used as a reference signal for the sensing receiver for subsequent processing. The other beam is input to the terahertz signal transmitting module to achieve coupling with another optical carrier signal, which is the optical local oscillator signal. The optical fiber delay line is used to introduce a loop delay for the integrated optical chaotic communication and sensing signal generated by the optical coupler 3. The adjustable attenuator 2 is used to adjust the optical power of the optical chaotic syn-inductive integrated signal after the loop delay of the optical fiber delay line feedback to meet the requirements of the photoelectric converter 2. The photoelectric converter 2 is used to convert the integrated optical chaotic communication and sensing signal into an electrical signal to achieve modulation of the optical carrier in the signal; The electric amplifier 2 is used to amplify the chaotic inductive integrated electrical signal output by the photoelectric converter 2 to meet the voltage requirements of the nonlinear modulation of the Mach-Zehnder modulator.

2. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 1, characterized in that, The multi-wavelength coherent light source module uses an electro-optic modulator or electro-optic cavity to generate an optical frequency comb. Two optical carriers are filtered out from the optical frequency comb using a filter. The frequency difference between the two optical carriers is equal to the terahertz frequency. The filter includes a passive filter or an active filter.

3. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 1, characterized in that, The communication signal module includes an optical amplifier 1, an optical coupler 1, a polarization controller 1, a polarization controller 2, a random signal generator, an electrical amplifier 1, an electro-optic modulator, an adjustable attenuator 1, and a polarization controller 3. The optical amplifier 1 is used to amplify a beam of optical carrier signal generated by the multi-wavelength coherent light source module; The optical coupler 1 is used to split the amplified optical carrier information into two beams. One beam is injected into the chaotic sensing signal module after the polarization state is adjusted by the polarization controller 2, and the other beam is input to the electro-optic modulator after the polarization state is adjusted by the polarization controller 1. The random signal generator is used to generate a plaintext radio frequency signal to be encrypted. The plaintext radio frequency signal is amplified by an amplifier 1 and then input into an electro-optic modulator. The electro-optic modulator is used to modulate the input optical carrier signal and modulate the plaintext radio frequency signal to be encrypted onto the optical carrier signal; The adjustable attenuator 1 is used to adjust the optical power of the communication plaintext radio frequency signal on the optical carrier, adjust the ratio used for coupling with the chaotic signal and output to the polarization controller 3; The polarization controller 3 is used to adjust the polarization state of the input signal so as to couple it with the chaotic signal and output it to the chaotic sensing signal module.

4. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 3, characterized in that, The optical amplifier 1 includes a semiconductor optical amplifier or an erbium-doped fiber amplifier; The electro-optic modulator includes a Mach-Zehnder modulator or a dual parallel Mach-Zehnder modulator.

5. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 1, characterized in that, The terahertz signal transmitting module includes an adjustable attenuator 3, an optical coupler 5, an optical amplifier 2, a polarization controller 4, an adjustable attenuator 5, and a terahertz signal transmitter; The adjustable attenuator 3 is used to adjust the optical power of another optical carrier signal, which is the optical local oscillator signal, so that it matches the power of the integrated optical chaotic communication and sensing optical signal output by the chaotic sensing signal module. The optical coupler 5 is used to couple the optical local oscillator signal with the optical chaotic communication sensing integrated optical signal. The resulting coupled optical signal is amplified by the optical amplifier 2 and then input to the polarization controller 4. The polarization controller 4 is used to adjust the polarization state of the coupled optical signal to maximize its output optical power, and then input it to the adjustable attenuator 2 for optical power adjustment to maximize the optical power of the optical signal input to the terahertz transmitter. The terahertz signal transmitter is used to generate and radiate a terahertz chaotic communication and sensing integrated signal based on the input optical signal.

6. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 1, characterized in that, The communication signal receiving module includes a terahertz signal receiver 1 and a communication signal processing module; The terahertz signal receiver 1 is used to receive the integrated terahertz chaotic communication and sensing signal and convert it into an intermediate frequency signal; The communication signal processing module is used to process the intermediate frequency signal, realize down-conversion, chaotic decryption, channel compensation, and recover the plaintext communication information of the transmitting end.

7. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 6, characterized in that, In the communication signal processing module, a neural network is used to achieve chaotic synchronization, thereby realizing chaotic decryption. The neural network includes at least one of a fully connected neural network, a convolutional neural network, a recurrent neural network, and a reservoir neural network.

8. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 1, characterized in that, The sensing signal receiving module includes a terahertz signal receiver 2 and a sensing signal processing module; The terahertz signal receiver 2 is used to receive the reflected signal of the terahertz chaotic communication and sensing integrated signal acting on the target object, and convert the reflected signal into an intermediate frequency signal. The sensing signal processing module is used to obtain sensing information by performing signal processing based on the intermediate frequency signal and the reference signal output by the chaotic sensing signal module.

9. The photonic terahertz secure communication and sensing integrated system based on chaotic signals according to claim 8, characterized in that, When the sensing signal processing module performs signal processing based on the intermediate frequency signal and combined with the reference signal output by the chaotic sensing signal module, it detects the distance, velocity, and two-dimensional or three-dimensional information of the communication signal receiving module and objects between the links through the range-Doppler algorithm, back projection algorithm, or compressed sensing algorithm.

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