High-capacity space-time safety optical communication system based on chaos micro comb

Abstract

The invention belongs to the technical field of physical layer security optical communication, and provides a high-capacity security optical communication system based on time-space double-layer encryption of a chaos micro comb. The system generates a chaotic optical frequency comb by using an optical fiber micro-ring, and extracts a plurality of comb tooth combinations from the chaotic optical frequency comb as a key entropy source. The key entropy source is used for carrying out time domain encryption on a signal to be transmitted, the encrypted signal and a chaotic signal are modulated to be in an orbital angular momentum mode of light through the spatial light modulator, the chaotic signal and the time domain encrypted signal are multiplexed in an opposite mode and then are transmitted to a receiving end through a free space link, and encryption of a spatial domain is achieved. And the receiving end separates the chaotic signal from the encrypted signal according to the pre-negotiated information, and executes time domain decryption to recover the original data. According to the method disclosed by the invention, double-layer encryption of a time domain and a space domain and multi-path parallel high-capacity secure communication can be realized, and the physical layer security and secure transmission efficiency of an optical communication system are improved.

Description

Technical Field

[0001] This invention belongs to the field of physical layer secure optical communication technology, specifically relating to a spatiotemporal domain optical signal encryption and decryption method based on chaotic microcomb, and a high-capacity spatiotemporal secure optical communication system using this method. Background Technology

[0002] With the widespread application of high-speed optical communication systems in scenarios such as data center interconnection, quantum-secure networks, and free-space optical communication, the physical layer security threats faced by communication links are becoming increasingly prominent. Because optical signals are vulnerable to attacks such as eavesdropping, beam splitting, or spatial pattern probing during transmission, simply relying on upper-layer encryption is insufficient to counter physical layer intrusions targeting the optical field itself. Therefore, researching physical layer security technologies that can directly perform encryption processing at the physical layer of optical field transmission has become an important direction.

[0003] Existing physical layer security technologies for free-space optical communication mainly include phase coding, intensity perturbation, mode perturbation, and spatial encryption methods based on spatial optical modulators. However, traditional spatial optical modulators are limited by refresh rate and modulation speed, resulting in limited real-time encryption capabilities in high-speed communication scenarios. Furthermore, some schemes rely on fixed spatial patterns or predictable modulation structures, leading to limited key spaces and making them vulnerable to joint analysis of time-domain or spatial-domain signals by high-performance detection equipment. On the other hand, the random characteristics of chaotic lasers or chaotic optical frequency combs have been proven to possess excellent unpredictability and high-dimensionality, making them suitable as physical layer key sources. However, existing schemes often only use chaotic signals for time-series perturbation, lacking joint encryption mechanisms in the time and spatial domains, making it difficult to simultaneously achieve high capacity, security, and scalability in multidimensional optical fields.

[0004] Therefore, there is an urgent need for an optical communication method that can simultaneously utilize the high-dimensional entropy characteristics of chaotic light sources and combine temporal and spatial domain encryption to improve physical layer security, expand the key space, and achieve high-capacity, multi-channel secure optical transmission. Summary of the Invention

[0005] This invention addresses the technical problems of insufficient physical layer security in existing optical communication systems, the difficulty in coordinating time-domain and spatial-domain encryption, and the challenge of balancing security and real-time performance in multi-channel high-capacity communication. It proposes a high-capacity spatiotemporal secure optical communication system based on a chaotic microcomb and its optical signal encryption / decryption method. This invention utilizes the high-dimensional randomness of a chaotic optical frequency comb to construct a physical layer key entropy source, and combines time-domain encryption with orbital angular momentum (OAM) mode modulation to achieve two-dimensional secure hiding of optical signals, thereby significantly improving the anti-eavesdropping capability and transmission security of the communication link.

[0006] The technical solution provided by this invention includes the following steps:

[0007] Chaotic entropy source generation: A chaotic optical frequency comb is generated by an optical fiber micro-ring pumped by a distributed feedback (DFB) laser. Multiple independent comb teeth are separated by a wavelength division multiplexer to form a multi-channel parallel chaotic key entropy source.

[0008] Time-domain encryption: Converts chaotic optical signals into electrical signals for time-series encryption of raw data. It can process multiple data streams simultaneously and achieve parallel encryption.

[0009] OAM spatial encryption: By using a spatial light modulator to load the temporal encryption signal and the chaotic signal into complementary OAM modes, spatial domain signal hiding is achieved.

[0010] OAM spatial decryption: The receiver uses a spatial optical processor to separate the chaotic signal from the encrypted signal based on the pre-shared mode information, thus completing spatial decryption.

[0011] Time-domain decryption: The receiving end uses the corresponding chaotic entropy source channel to reverse the encrypted signal and recover the original data.

[0012] Through the above technical solution, the present invention achieves dual-layer encryption in the time domain and spatial domain, supports multi-channel parallel transmission, and has high capacity, high security and anti-eavesdropping capabilities. It is suitable for various physical layer secure communication scenarios such as free space optical communication and short-distance high-speed interconnection. Attached image description:

[0013] Figure 1 A schematic diagram of the spatiotemporal optical signal encryption and decryption method based on chaotic microcomb provided in this embodiment of the invention;

[0014] Figure 2 : A schematic diagram of the structure of a high-capacity spatiotemporal secure optical communication system based on chaotic microcomb provided in this embodiment of the invention; Detailed implementation method:

[0015] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in conjunction with the accompanying drawings and embodiments. It should be understood that the following embodiments are only used to illustrate the technical concept of this invention and are not intended to limit the invention.

[0016] like Figure 1 and Figure 2 As shown, the system and method proposed in this invention mainly include: a laser pumping module 101, an optical fiber microring 102, a wavelength division multiplexer 103, communication signal sources 201-204, a time-domain encryption module 301-304, a spatial encryption module 305, a spatial decryption module 401, an erbium-doped fiber amplifier 402-405, a time-domain decryption module 406-409, and a signal receiver / collector 501-504.

[0017] I. System Structure Implementation Examples

[0018] 101 Laser Pump Module:

[0019] Used to provide stable pump light for fiber microrings, ensuring the generation of chaotic optical frequency combs. Includes a distributed feedback laser, polarization controller, isolator, and erbium-doped fiber amplifier.

[0020] 102 Fiber Microring:

[0021] As a chaotic optical frequency comb generation unit, it generates a broadband, multi-tooth chaotic signal under pump light injection, forming a high-dimensional, independent physical layer key entropy source.

[0022] 103WDM multiplexer:

[0023] The chaotic optical frequency comb is decomposed into multiple channels to achieve multi-channel independent chaotic entropy source output.

[0024] 201~204 communication signal source:

[0025] It generates multiple independent data sequences to provide input signals for multi-channel parallel communication.

[0026] Time-domain encryption modules 301-304:

[0027] The module utilizes a chaotic entropy source to perform time-series encryption on communication signals. It includes a photodetector, a continuous wavelength laser, and a Mach-Zehnder modulator.

[0028] 305 Space Encryption Module:

[0029] By loading the encrypted signal into a specified OAM mode using a spatial light modulator, and simultaneously loading the chaotic signal into a complementary OAM mode, spatial domain signal hiding is achieved.

[0030] 401 Space Decryption Module:

[0031] The receiver uses a spatial optical processor or an OAM beam splitter to separate the chaotic signal and the encrypted signal, providing a key for subsequent time-domain decryption.

[0032] 402-405 Erbium-doped fiber amplifiers:

[0033] The power of each signal after spatial decryption is adjusted to ensure the requirements of time-domain decryption processing.

[0034] 406-409 Time Domain Decryption Module:

[0035] By using a photodetector, inverter, and power divider, the chaotic key is matched with the encrypted signal to achieve the recovery of the original time series.

[0036] Signal receivers and acquisition units 501-504:

[0037] It receives and collects the decrypted optical signal to fully recover the original information.

[0038] II. Method Flow Examples

[0039] Step S1: Generation of Chaotic Entropy Source

[0040] The pump light output from the laser pump module is injected into the fiber microring to generate a chaotic optical frequency comb, which is then separated into multiple independent chaotic signals by a wavelength division multiplexer.

[0041] Step S2: Time Domain Encryption

[0042] After the chaotic optical signal is converted into an electrical signal, it performs time-series perturbation on the communication data to form a multi-channel parallel encrypted signal.

[0043] Step S3: Spatial Domain Encryption

[0044] By loading encrypted signals into the OAM mode using a spatial light modulator, and simultaneously loading chaotic light into the complementary mode, spatial concealment is achieved.

[0045] Step S4: Spatial Domain Decryption

[0046] The receiver uses a spatial optical processor to separate the chaotic signal from the encrypted signal, thus completing spatial decryption.

[0047] Step S5: Time Domain Decryption

[0048] The encrypted signal is decrypted using the corresponding chaotic key to recover the original time series.

[0049] III. Implementation Results

[0050] This invention constructs multiple independent physical layer key entropy sources based on chaotic microcombs and combines temporal encryption with orbital angular momentum (OAM) spatial encryption to form a two-dimensional superimposed encryption structure. Through the inherent high-dimensional randomness of the chaotic comb teeth, parallel generation and mutual independence of multi-channel keys are achieved; through the orthogonality of the OAM modes, the encrypted signal is effectively masked by chaotic signals in the spatial domain, significantly enhancing the communication link's resistance to eavesdropping.

[0051] The system structure of this invention is clear and highly modular, supporting multiple temporal encryption and multi-mode spatial encryption simultaneously under the same chaotic microcomb entropy source. It reliably recovers signals without complex synchronization control, which is beneficial for deployment and expansion in practical free-space optical communication systems. Compared with existing single-dimensional encryption methods based solely on the temporal or spatial domains, this invention significantly improves system security, transmission capacity, parallelism, and anti-interference capabilities by introducing a chaotic microcomb-OAM collaborative encryption mechanism. In particular, the spatiotemporal dual-domain encryption structure simultaneously increases the key space and information hiding depth, making it suitable for scenarios such as high-capacity free-space optical communication, short-distance high-speed interconnection, and physical layer secure transmission, demonstrating high engineering practicality and development potential.

[0052] IV. Additional Notes

[0053] The above embodiments are only used to illustrate the technical solutions, to facilitate understanding and implementation by those skilled in the art, and do not constitute a limitation on the scope of protection of the present invention. Without departing from the principles and essence of the present invention, those skilled in the art can make various modifications and improvements to the above embodiments, and such modifications and improvements should also fall within the scope of protection of the present invention.

Claims

1. A spatiotemporal secure optical encryption and decryption system based on chaotic microcombs, characterized in that, The system comprises a chaotic microcomb generation module, a time-domain encryption module, an OAM mode generation and multiplexing module, a spatial disturbance module, a receiving end demultiplexing module, a chaotic synchronization and decryption module, wherein: The chaotic microcomb generation module is used for generating a multi-tooth chaotic optical frequency comb in a microcavity under the driving of a pump laser. The time-domain encryption module is used for selecting a plurality of chaotic teeth as a key sequence and performing time-domain covering on an input optical signal. The OAM mode generation and multiplexing module is used for modulating the encrypted optical signal into a plurality of OAM modes to realize spatial domain encryption. The spatial disturbance module is used for applying phase disturbance to the multi-mode optical field to enhance spatial aliasing. The receiving end demultiplexing module is used for recovering the OAM mode and restoring the time-domain chaotic key of each path. The chaotic synchronization and decryption module generates and sends the chaotic key sequence consistent with the sending end by using a synchronous chaotic microcavity, thereby completing decryption and recovery. The system comprises:

2. A spatiotemporal secure optical encryption and decryption method based on chaotic microcombs, characterized in that, Step A: generating a chaotic optical frequency comb by a microcavity under stimulated pumping, and selecting a plurality of teeth as a key source by a multi-channel filter; Step B: using a chaotic key to perform time-domain covering or modulation on an input signal to realize physical layer encryption in the time-domain layer; Step C: using an OAM mode modulator to map the time-domain encrypted optical signal into a plurality of orthogonal OAM modes to realize spatial domain encryption; Step D: using a phase disturbance device or a random scattering element to disturb the multiplexed OAM mode in space; Step E: the receiving end reconstructs the chaotic key sequence by using an OAM demultiplexer and a synchronous chaotic microcomb, and sequentially completes double decryption in the spatial domain and the time domain.

3. The system of claim 1, wherein: The chaotic microcomb generation module comprises a pump laser, a micro-ring or micro-disk resonant cavity, a temperature control unit and a coupling structure, and is used for realizing stable output of high-coherence chaotic microcomb.

4. The system of claim 1, wherein: The time-domain encryption module comprises an adjustable optical filter, an optical amplifier and an electro-optical modulator, and is used for realizing random covering or amplitude and phase modulation according to the instantaneous waveform of the chaotic tooth.

5. The system of claim 1, wherein: The OAM mode generation and multiplexing module comprises a polarization controller, a spatial light modulator, a spiral phase plate or an integral multi-mode multiplexer, and is used for generating and multiplexing a plurality of OAM modes with different topological charges.

6. The system of claim 1, wherein: The spatial disturbance module uses a random phase plate, a vortex disturbance device or a scatterer with a specific structure to nonlinearly disturb the spatial field distribution to increase the decryption difficulty.

7. The method of claim 2, wherein: In step A, the tooth spacing, spectral width and chaotic degree of the chaotic optical frequency comb are dynamically controlled by adjusting the pump power, the in-cavity dispersion and the thermal tuning.

8. The method of claim 2, wherein: The OAM mode used in step C comprises positive integer, negative integer and high-order topological charge mode to improve the spatial domain key space and parallel transmission capacity.

9. The method of any one of claims 2 to 8, wherein: ​ The method is suitable for free space optical communication, large capacity short distance interconnection, physical layer secure transmission and multi-dimensional parallel encryption communication scenarios.

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