Non-vision field optical communication device and method based on partially coherent vortex optical field

Abstract

The invention discloses a non-vision field optical communication device and method based on a partially coherent vortex light field, and belongs to the technical field of laser, and the device comprises a laser device which is used for generating a Gaussian laser beam; the first light modulation module is used for converting the Gaussian laser beam into a partially coherent Gaussian-Shell model light beam; the second light modulation module is used for converting the Gaussian-Schell model light beam into a Laguerre Gaussian-Schell model vortex light beam; the third light modulation module is used for shielding the Laguerre Gaussian-Shell model vortex light beam and then obtaining a modulated light beam through phase modulation; wherein the modulation phases are two diffraction phases obtained through light diffraction neural network training, and after light beams modulated through the first diffraction phase and the second diffraction phase in sequence are transmitted for a fixed distance, the light beams are displayed as rectangular light beams at different positions under the condition of different topological charges; and the light beam receiving and identifying module is used for receiving the rectangular light beams at different positions and completing non-vision field optical communication through light beam identification.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, and particularly relates to a non-line-of-sight optical communication device and method based on a partially coherent vortex optical field. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Free-space optical communication (FSO) boasts advantages such as high bandwidth, resistance to electromagnetic interference, and flexible deployment, making it valuable for applications in emergency communications, interplanetary communications, and urban backbone network coverage. Its core transmission mechanism relies on line-of-sight propagation, requiring a clear and unobstructed line of sight between the transmitter and receiver for stable signal transmission. However, in complex real-world environments, these ideal conditions are often difficult to achieve. Factors such as buildings, trees, and weather conditions can interfere with or even interrupt signal transmission, significantly limiting the application scope of free-space optical communication. Therefore, developing non-line-of-sight optical communication technology to overcome the limitations of line-of-sight propagation and enable stable operation in complex environments has become a crucial research direction in the field of optical communication. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a non-line-of-sight optical communication device and method based on a partially coherent vortex light field. In non-line-of-sight scenarios, a partially coherent vortex beam is combined with an optical diffraction neural network to construct an optical communication link, thereby improving the performance of the communication system and enabling efficient, reliable, and accurate non-line-of-sight optical communication in a wider range of scenarios. This solves the problem that existing free-space optical communication relies on line-of-sight propagation, is easily interfered with in complex environments leading to communication interruptions, and is difficult to form an efficient and reliable solution.

[0005] In a first aspect, the present invention provides a non-line-of-sight optical communication device based on a partially coherent vortex optical field.

[0006] A non-line-of-sight optical communication device based on a partially coherent vortex optical field includes: Lasers are used to generate Gaussian laser beams; The first optical modulation module is used to convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam. The second optical modulation module is used to convert the Gauss-Scher model beam into a Laguerre-Gauss-Scher model vortex beam. The third optical modulation module is used to block the Laguerre Gauss-Sher model vortex beam and then obtain a modulated beam through phase modulation. The modulation phase is two diffraction phases obtained by training the optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence will appear as a rectangular beam at different positions after transmitting a fixed distance under different topological charge numbers. The beam receiving and identification module is used to receive rectangular beams at different positions and complete non-line-of-sight optical communication based on a partially coherent vortex optical field through beam identification.

[0007] In a further technical solution, the laser is a helium-neon laser.

[0008] In a further technical solution, the first optical modulation module includes a beam expander, a first thin lens, a rotating frosted glass, a second thin lens, and a Gaussian filter arranged sequentially. Among them, the beam expander is used to expand the Gaussian laser beam generated by the laser to obtain the expanded laser beam; The first thin lens is used to focus the expanded laser beam to obtain the focused laser beam; A rotating frosted glass plate is used to reduce the coherence of the focused laser, converting it into completely incoherent light; The second thin lens is used to perform a Fourier transform on the completely incoherent light to obtain the transformed completely incoherent light. Gaussian filters are used to modulate and filter the amplitude of the transformed, completely incoherent light, and output a partially coherent Gaussian-Sher model beam.

[0009] In a further technical solution, the second optical modulation module includes a first spatial light modulator, a third thin lens, an aperture, and a fourth thin lens; The first spatial light modulator is used to load the Laguerre amplitude vortex phase onto the Gauss-Scher model beam to generate a Laguerre-Gauss-Scher model vortex beam. The third thin lens, the aperture stop, and the fourth thin lens are used together to filter out the first-order diffracted Laguerre-Gauss-Sher model vortex beams in the Laguerre-Gauss-Sher model vortex beam.

[0010] In a further technical solution, the second optical modulation module also includes a blocking object, which is disposed after the fourth thin lens and is used to block the first-order diffracted Laguerre-Gauss-Sher model vortex beam.

[0011] In a further technical solution, the third optical modulation module includes a second spatial light modulator, a right-angle prism, and a reflector; The second spatial light modulator is divided into two parts: the left half is used to load the first diffraction phase obtained by training the optical diffraction neural network, and the right half is used to load the second diffraction phase obtained by training the optical diffraction neural network. A right-angle prism is used to reflect the beam modulated by the first diffraction phase to the right half of the second spatial light modulator, so that it is further loaded with the second diffraction phase. The reflector is used to reflect the beam modulated by the second diffraction phase to a fixed distance, so that beams with different topological charges form rectangular beams at different positions at the fixed distance.

[0012] In a further technical solution, the optical diffraction neural network consists of multiple diffraction layers, including an input layer, a first phase modulation layer, a second phase modulation layer, and a detector layer; The optical diffraction neural network is trained to obtain two corresponding diffraction phases for beam modulation, as follows: Using the occluded Laguerre Gauss-Schel model vortex beam as the training sample input and the unoccluded Laguerre Gauss-Schel model vortex beam as the training sample output, the beam propagates forward and is aggregated at the detector layer to obtain the final optical field intensity. The mean square error between the optical field intensity of the detector layer and the target optical field intensity is used as the loss. The training is iterated continuously through the backpropagation algorithm until the loss is minimized, thus completing the training and obtaining the two diffraction phases in the first and second phase modulation layers.

[0013] In a further technical solution, the beam receiving and recognition module includes a charge-coupled element, which is disposed at a fixed distance behind the reflector. The fixed distance is consistent with the fixed distance at which the beam modulated by the second diffraction phase forms a rectangular beam, and is used to accurately capture and record the rectangular beam at different positions.

[0014] Secondly, the present invention provides a non-line-of-sight optical communication method based on a partially coherent vortex optical field.

[0015] A non-line-of-sight optical communication method based on a partially coherent vortex optical field, implemented using the non-line-of-sight optical communication device based on a partially coherent vortex optical field proposed in the first aspect, includes: Convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam; Transform the Gauss-Sher model beam into a Laguerre-Gauss-Sher model vortex beam; The Laguerre Gauss-Sher model vortex beam is blocked and then phase-modulated to obtain a modulated beam. The modulation phase is two diffraction phases obtained by training an optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence appears as a rectangular beam at different positions under different topological charge numbers after transmitting a fixed distance. It receives rectangular light beams from different positions and completes non-line-of-sight optical communication based on a partially coherent vortex light field through beam recognition.

[0016] Thirdly, the present invention provides a non-line-of-sight optical communication method based on a partially coherent vortex optical field.

[0017] A non-line-of-sight optical communication method based on a partially coherent vortex optical field includes: The data to be transmitted is encoded using Laguerre-Gauss-Sher model vortex beams with different topological charge numbers; Following the steps of the method described in the second aspect, the encoded Laguerre Gauss-Sher model vortex beams with different topological charge numbers are made into rectangular beams at different positions at a fixed distance. By using charge-coupled devices to record rectangular light beams at different locations and identifying the location of the maximum light intensity, a non-line-of-sight optical communication link based on a partially coherent vortex light field is obtained, enabling data transmission.

[0018] The above one or more technical solutions have the following beneficial effects: 1. This invention proposes a non-line-of-sight optical communication device and method based on a partially coherent vortex light field. In non-line-of-sight scenarios, a partially coherent vortex beam is combined with an optical diffraction neural network to construct an optical communication link. This fully utilizes the advantages of the partially coherent vortex beam in terms of anti-turbulence, anti-scattering, and multi-data stream transmission, while leveraging the characteristics of the optical diffraction neural network in terms of light-speed operation and low energy consumption. This constructs a highly efficient and accurate non-line-of-sight optical communication link, breaking through the limitation of traditional free-space optical communication that relies on line-of-sight propagation, improving the performance of the communication system, and realizing highly efficient, reliable, and accurate non-line-of-sight optical communication in a wider range of scenarios.

[0019] 2. In this invention, the modules in the device have clear division of labor and close cooperation. From laser generation to rectangular beam formation and recording, each link is precisely designed to ensure that the beam modulation, phase loading and other processes are stable and reliable, thereby improving the stability and reliability of non-line-of-sight optical communication.

[0020] 3. This invention provides two communication methods: one is suitable for conventional non-line-of-sight optical communication scenarios, and the other further enhances the flexibility and applicability of communication through data encoding. It can meet different non-line-of-sight optical communication needs, providing a brand-new technical solution for the field of non-line-of-sight optical communication and has broad application prospects.

[0021] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram of the structure of a non-line-of-sight optical communication device based on a partially coherent vortex optical field in an embodiment of the present invention; Figure 2 ( a() is a Laguerre-Gauss-Sher model vortex beam with a topological charge of 4 after being blocked in this embodiment of the invention; Figure 2 ( b () represents the rectangular beam at the position corresponding to the topological charge 4 in this embodiment of the invention; Figure 3 ( a () represents the first diffraction phase used in training the optical diffraction neural network in this embodiment of the invention; Figure 3 ( b () represents the second diffraction phase for training the optical diffraction neural network in this embodiment of the invention.

[0024] Among them, 1. Laser; 2. Beam expander; 3. First thin lens; 4. Ground glass plate; 5. Second thin lens; 6. Gaussian filter; 7. First spatial light modulator; 8. Third thin lens; 9. Aperture; 10. Fourth thin lens; 11. Obstruction; 12. Second spatial light modulator; 13. Right angle prism; 14. Mirror; 15. Charge-coupled device. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are exemplary and are intended only to describe specific embodiments and to provide further explanation of the invention, and are not intended to limit the scope of exemplary embodiments of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Vortex beams, as special beams carrying orbital angular momentum (OAM), exhibit a spiral shape in their wavefront and can be transmitted through phase factors. (in For topological load number, Described by azimuth angle, vortex beams with different topological charges exhibit orthogonal characteristics, enabling the parallel transmission of multiple independent data streams in the same frequency channel, thereby significantly increasing the capacity of the communication system. By reducing the random light field generated by beam coherence, resistance to turbulence and scattering can be effectively improved. Furthermore, through specific design, it can adapt to different channel conditions, enhancing signal stability and reliability. Therefore, utilizing random light fields in non-line-of-sight optical communication links can effectively address various scenarios. Optical diffraction neural networks consist of multiple diffraction layers, with each point on the layer acting as a neuron. By adjusting phase information, they control the propagation path and intensity distribution of light waves. Their training process is similar to traditional deep learning, but the final output is the specific settings of each phase unit rather than the weights. Moreover, the trained optical diffraction neural network can operate at the speed of light with low energy consumption.

[0027] Addressing the issues raised in the background section regarding existing free-space optical communication relying on line-of-sight propagation, which is susceptible to interference in complex environments leading to communication interruptions and hindering efficient and stable communication, this invention proposes a non-line-of-sight optical communication device and method based on a partially coherent vortex light field. This method utilizes a combination of a partially coherent vortex light field and a light diffraction neural network to construct an optical communication link, overcoming the shortcomings of existing solutions in terms of communication capacity, anti-interference capability, and transmission accuracy, thereby achieving efficient and stable non-line-of-sight optical communication in complex environments.

[0028] Example 1 This embodiment provides a non-line-of-sight optical communication device based on a partially coherent vortex optical field, the device specifically comprising: Lasers are used to generate Gaussian laser beams; The first optical modulation module is used to convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam. The second optical modulation module is used to convert the Gauss-Scher model beam into a Laguerre-Gauss-Scher model vortex beam. The third optical modulation module is used to block the Laguerre Gauss-Sher model vortex beam and then obtain a modulated beam through phase modulation. The modulation phase is two diffraction phases obtained by training the optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence will appear as a rectangular beam at different positions after transmitting a fixed distance under different topological charge numbers. The beam receiving and identification module is used to receive rectangular beams at different positions and complete non-line-of-sight optical communication based on a partially coherent vortex optical field through beam identification.

[0029] The following content provides a detailed description of the non-line-of-sight optical communication device based on a partially coherent vortex optical field proposed in this embodiment.

[0030] like Figure 1 As shown, the laser is a helium-neon laser 1, used to generate a stable Gaussian laser beam. The first optical modulation module includes a beam expander 2, a first thin lens 3, a rotating frosted glass plate 4, a second thin lens 5, and a Gaussian filter 6 arranged sequentially. The Gaussian laser spot emitted by the helium-neon laser 1 first passes through the beam expander 2, which expands the Gaussian laser beam to obtain the expanded laser. The expanded spot is then focused by the first thin lens 3 onto the rotating frosted glass plate 4 to reduce coherence and convert it into completely incoherent light. Then, it passes through the second thin lens 5 to perform a Fourier transform on the completely incoherent light to obtain the transformed completely incoherent light. Finally, the beam is amplitude-modulated by the Gaussian filter 6 to output a partially coherent Gaussian-Sher model beam.

[0031] Furthermore, the second optical modulation module includes a first spatial light modulator 7, a third thin lens 8, an aperture 9, a fourth thin lens 10, and a blocking object 11 arranged sequentially. The Gauss-Schel model beam is modulated by the first spatial light modulator 7, and by loading the Laguerre amplitude vortex phase, a Laguerre-Gauss-Schel model vortex beam is output. The third thin lens 8, aperture 9, and fourth thin lens 10 work together to filter out the first-order diffracted Laguerre-Gauss-Schel model vortex beam from the Laguerre-Gauss-Schel model vortex beam. The first-order diffracted Laguerre-Gauss-Schel model vortex beam is blocked by the blocking object 11. In this embodiment, the blocking object 11 is a glass plate coated with black markings. The beam cannot pass through the black markings on the glass plate, but the beam can pass through other positions. Using this blocking object for blocking allows for convenient control of the size and shape of the blocking.

[0032] Furthermore, the third optical modulation module includes a second spatial light modulator 12, a right-angle prism 13, and a reflector 14. The blocked light beam is incident on the second spatial light modulator 12, which is divided into left and right parts, each loaded with two diffraction phases obtained from training an optical diffraction neural network. Specifically, the left half is loaded with the first diffraction phase obtained from training the optical diffraction neural network, such as... Figure 3 As shown in (a), the right half is loaded with the second diffraction phase obtained from training an optical diffraction neural network, as follows: Figure 3 As shown in (b); the right-angle prism 13 is disposed on the light-emitting side of the left half of the second spatial light modulator 12, at a 45° angle to the beam propagation direction, and is used to reflect the beam modulated by the first diffraction phase to the right half of the second spatial light modulator 12, so that it is further loaded with the second diffraction phase; the reflector 14 is disposed on the light-emitting side of the right half of the second spatial light modulator 12, at a 45° angle to the beam propagation direction, and is used to reflect the beam modulated by the second diffraction phase to a fixed distance, so that beams with different topological charges form rectangular beams at different positions at this fixed distance. The beam modulated by the second diffraction phase is reflected by the reflector 14 to a fixed distance, and the rectangular beams at different positions are located at this fixed distance. The charge-coupled element 15 is located at a fixed distance behind the reflector and is used to capture and record the rectangular beams at different positions. For example, when the topological charge is 4, it forms as shown in the figure. Figure 2 The rectangular beam shown in (b) has a corresponding blocked beam as follows: Figure 2 As shown in (a).

[0033] In this embodiment, the introduced optical diffraction neural network consists of multiple diffraction layers, including an input layer, a first phase modulation layer, a second phase modulation layer, and a detector layer. Each node in the layer can be considered as a neuron in the neural network, and the phase and amplitude distribution of the diffraction neurons can achieve beam modulation. Specifically, the neurons in the previous layer propagate to the subsequent layers according to the Rayleigh–Sommerfeld diffraction equation. Layer coordinates are The Each node, in Layer coordinates are The secondary light field distribution generated at the node for: (1) In the above formula, The operating wavelength of the incident light; j It is a complex number; the wavefront propagation distance r satisfy: .

[0034] No. Layer coordinates are The Output light field of each node ,Depend on The output light field of the layer is incident on the node. i All incident light fields and nodes i The phase and amplitude are jointly determined, and can be expressed as: (2) in, yes All layers k A node is incident to a node. i The incident light field, For the first Layer coordinates are The The transmission function of each node can be expressed as: (3) in, For nodes i The amplitude, For nodes i The phase, in the pure phase diffraction layer .

[0035] Furthermore, the constructed optical diffraction neural network is trained to obtain two corresponding diffraction phases for beam modulation, realizing non-line-of-sight optical communication based on a partially coherent vortex square. The training process of the optical diffraction neural network includes beam forward propagation and error backward propagation. Specifically, the occluded Laguerre-Gauss-Schel model vortex beam is used as the training sample input, and the unoccluded Laguerre-Gauss-Schel model vortex beam is used as the training sample output; both input and output samples are obtained through simulation. The light field distribution of the input layer can be represented as... The light field that the beam propagates forward to the detector layer can then be derived as follows: (4) Therefore, the light field intensity of the system at the detector layer can be expressed as: .

[0036] Defined as the light field intensity of the probe layer and target light field intensity The mean squared error function between them is the loss function, expressed as: With the goal of minimizing the loss, iterative training is conducted to optimize the following issues: (5) In the aforementioned iterative training process, the gradient of the optical diffraction neural network is a vector. The direction of gradient ascent indicates the direction in which the error function increases the fastest among all trainable variables. During each training cycle, the system weights are updated and iterated. This causes the loss function value to continuously decrease, meaning the actual output light intensity gradually approaches the desired output light intensity. When the light intensity deviation drops to an acceptable range (or a preset range), the learning and training process of the optical diffraction neural network terminates, and the weights obtained at this point are... The distribution (characterizing phase and amplitude) is the optimal weight for the optical diffraction neural network.

[0037] After training, the diffraction phase obtained from the training is applied to the communication system, which can display the blocked Laguerre Gauss-Sher model vortex beam as a rectangular beam at the corresponding position at the detector end in real time during the decoding process, greatly shortening the information decoding time and improving communication efficiency.

[0038] Using the method proposed in this embodiment, after being blocked, the vortex beams of different topological Hora-Gail-Gauss-Sher model generate rectangular beams at corresponding positions at the detector end after being modulated by two diffraction phases. This process only requires the time of light propagation, which greatly shortens the decoding time. This enables a highly efficient non-line-of-sight optical communication link. Moreover, during the training process of the optical diffraction neural network, the backpropagation of errors is used to make the output light intensity gradually approach the desired output light intensity. By increasing the diversity of input samples, the optical diffraction neural network can adapt to different obstructions and the anti-turbulence characteristics of some coherent beams, which can effectively improve the accuracy in the non-line-of-sight optical communication link.

[0039] Example 2 This embodiment provides a non-line-of-sight optical communication method based on a partially coherent vortex optical field, implemented using the non-line-of-sight optical communication device based on a partially coherent vortex optical field proposed in Embodiment 1, specifically including the following steps: Convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam; Transform the Gauss-Sher model beam into a Laguerre-Gauss-Sher model vortex beam; The Laguerre Gauss-Sher model vortex beam is blocked and then phase-modulated to obtain a modulated beam. The modulation phase is two diffraction phases obtained by training an optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence appears as a rectangular beam at different positions under different topological charge numbers after transmitting a fixed distance. It receives rectangular light beams from different positions and completes non-line-of-sight optical communication based on a partially coherent vortex light field through beam recognition.

[0040] Specifically, in step S1, the Gaussian laser beam generated by laser 1 passes through beam expander 2 to obtain expanded laser beam.

[0041] The laser obtained in steps S2 and S1 is incident on the first thin lens 3 to obtain a focused laser.

[0042] In steps S3 and S2, the laser beam is incident on the rotating frosted glass plate 4. The completely coherent signal beam is converted into completely incoherent light after passing through the dynamically rotating frosted glass plate 4.

[0043] The completely incoherent light obtained in steps S4 and S3 is subjected to Fourier transform by the second thin lens 5 and then filtered and shaped by the Gaussian filter 6 to obtain a Gaussian-Sher model beam.

[0044] The Gauss-Sher model beams obtained in steps S5 and S4 are incident on the first spatial light modulator 7. After being loaded with Laguerre amplitude vortex phase, they are filtered out by the third thin lens 8, the aperture 9, and the fourth thin lens 10 to produce a first-order diffraction Laguerre-Gauss-Sher model vortex beam.

[0045] After the Laguerre Gauss-Sher model vortex beam obtained in steps S6 and S5 is blocked by an obstruction 11 placed at a certain distance, it is incident on the left half of the second spatial light modulator 12 and loaded with the first diffraction phase trained by the optical diffraction neural network.

[0046] The light beams modulated by the first diffraction phase in steps S7 and S6 are reflected by the right-angle prism 13 and then incident on the right half of the second spatial light modulator 12, which loads the second diffraction phase trained by the optical diffraction neural network.

[0047] After propagating a fixed distance, the beam modulated by the second diffraction phase in steps S8 and S7 appears as a rectangular beam at different positions under different topological charge numbers.

[0048] Step S9: Import rectangular beams at different positions into the program for identification to achieve non-line-of-sight optical communication based on partially coherent vortex optical fields.

[0049] Example 3 This embodiment provides a method for non-line-of-sight optical communication based on a partially coherent vortex optical field, implemented using the non-line-of-sight optical communication device based on a partially coherent vortex optical field proposed in Embodiment 1, including: The data to be transmitted is encoded using Laguerre-Gauss-Sher model vortex beams with different topological charge numbers; Following the steps of the method described in Embodiment 2, the encoded Laguerre Gauss-Sher model vortex beams with different topological charge numbers are made into rectangular beams at different positions at a fixed distance. By using charge-coupled devices to record rectangular light beams at different locations and identifying the location of the maximum light intensity, a non-line-of-sight optical communication link based on a partially coherent vortex light field is obtained, enabling data transmission.

[0050] The steps involved in Examples 2 and 3 above correspond to those in Example 1. For specific implementation details, please refer to the relevant description section of Example 1.

[0051] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention has been described in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A non-line-of-sight optical communication device based on a partially coherent vortex optical field, characterized in that, include: Lasers are used to generate Gaussian laser beams; The first optical modulation module is used to convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam. The second optical modulation module is used to convert the Gauss-Scher model beam into a Laguerre-Gauss-Scher model vortex beam. The third optical modulation module is used to block the Laguerre Gauss-Sher model vortex beam and then obtain a modulated beam through phase modulation. The modulation phase is two diffraction phases obtained by training the optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence will appear as a rectangular beam at different positions after transmitting a fixed distance under different topological charge numbers. The beam receiving and identification module is used to receive rectangular beams at different positions and complete non-line-of-sight optical communication based on a partially coherent vortex optical field through beam identification.

2. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 1, characterized in that, The laser used is a helium-neon laser.

3. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 1, characterized in that, The first optical modulation module includes a beam expander, a first thin lens, a rotating frosted glass, a second thin lens, and a Gaussian filter arranged sequentially. Among them, the beam expander is used to expand the Gaussian laser beam generated by the laser to obtain the expanded laser beam; The first thin lens is used to focus the expanded laser beam to obtain the focused laser beam; A rotating frosted glass plate is used to reduce the coherence of the focused laser, converting it into completely incoherent light; The second thin lens is used to perform a Fourier transform on the completely incoherent light to obtain the transformed completely incoherent light. Gaussian filters are used to modulate and filter the amplitude of the transformed, completely incoherent light, and output a partially coherent Gaussian-Sher model beam.

4. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 1, characterized in that, The second optical modulation module includes a first spatial light modulator, a third thin lens, an aperture, and a fourth thin lens; The first spatial light modulator is used to load the Laguerre amplitude vortex phase onto the Gauss-Sher model beam to generate a Laguerre-Gauss-Sher model vortex beam. The third thin lens, the aperture stop, and the fourth thin lens are used together to filter out the first-order diffracted Laguerre-Gauss-Sher model vortex beams in the Laguerre-Gauss-Sher model vortex beam.

5. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 4, characterized in that, The second optical modulation module also includes a blocking device, which is positioned behind the fourth thin lens and is used to block the first-order diffracted Laguerre-Gauss-Sher model vortex beam.

6. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 1, characterized in that, The third optical modulation module includes a second spatial optical modulator, a right-angle prism, and a reflector; The second spatial light modulator is divided into two parts: the left half is used to load the first diffraction phase obtained by training the optical diffraction neural network, and the right half is used to load the second diffraction phase obtained by training the optical diffraction neural network. A right-angle prism is used to reflect the beam modulated by the first diffraction phase to the right half of the second spatial light modulator, so that it is further loaded with the second diffraction phase. The reflector is used to reflect the beam modulated by the second diffraction phase to a fixed distance, so that beams with different topological charges form rectangular beams at different positions at the fixed distance.

7. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 6, characterized in that, The optical diffraction neural network consists of multiple diffraction layers, including an input layer, a first phase modulation layer, a second phase modulation layer, and a detector layer; The optical diffraction neural network is trained to obtain two corresponding diffraction phases for beam modulation, as follows: Using the occluded Laguerre Gauss-Schel model vortex beam as the training sample input and the unoccluded Laguerre Gauss-Schel model vortex beam as the training sample output, the beam propagates forward and is aggregated at the detector layer to obtain the final optical field intensity. The mean square error between the optical field intensity of the detector layer and the target optical field intensity is used as the loss. The training is iterated continuously through the backpropagation algorithm until the loss is minimized, thus completing the training and obtaining the two diffraction phases in the first and second phase modulation layers.

8. The non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in claim 1, characterized in that, The beam receiving and recognition module includes a charge-coupled element, which is located at a fixed distance behind the reflector. The fixed distance is consistent with the fixed distance at which the beam modulated by the second diffraction phase forms a rectangular beam, and is used to accurately capture and record the rectangular beam at different positions.

9. A non-line-of-sight optical communication method based on a partially coherent vortex optical field, characterized in that, Implemented using the non-line-of-sight optical communication device based on a partially coherent vortex optical field as described in any one of claims 1-8, comprising: Convert the Gaussian laser beam into a partially coherent Gaussian-Sher model beam; Transform the Gauss-Sher model beam into a Laguerre-Gauss-Sher model vortex beam; The Laguerre Gauss-Sher model vortex beam is blocked and then phase-modulated to obtain a modulated beam. The modulation phase is two diffraction phases obtained by training an optical diffraction neural network. The beam modulated by the first and second diffraction phases in sequence appears as a rectangular beam at different positions under different topological charge numbers after transmitting a fixed distance. It receives rectangular light beams from different positions and completes non-line-of-sight optical communication based on a partially coherent vortex light field through beam recognition.

10. A non-line-of-sight optical communication method based on a partially coherent vortex optical field, characterized in that, include: The data to be transmitted is encoded using Laguerre-Gauss-Sher model vortex beams with different topological charge numbers; According to the steps of the non-line-of-sight optical communication method based on partially coherent vortex optical field as described in claim 9, the encoded Laguerre Gauss-Sher model vortex beams with different topological charge numbers form rectangular beams at different positions at a fixed distance. By using charge-coupled devices to record rectangular light beams at different locations and identifying the location of the maximum light intensity, a non-line-of-sight optical communication link based on a partially coherent vortex light field is obtained, enabling data transmission.

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