Optical and electrical integrated synthetic space optical communication multi-aperture receiving method

Abstract

This invention provides a multi-aperture receiving method for space optical communication that integrates optical and electrical synthesis. It employs a densely packed multi-aperture optical antenna to intelligently adjust the number of sub-apertures in the optical beam combiner, ensuring the independence of the optical signals in the combined beam. An optical antenna array, with the total number of sub-apertures determined based on the receiving plane, receives the optical signals and corrects for first and second-order Zernike aberrations. The optical signals are transmitted via an optical beam splitter; a portion is input to a coupled energy photodetector and converted into voltage or current feedback signals, which are then input to a control module; the other portion is input to an N×1 adaptive beam combining module. The optical signals are coherently combined through the N×1 adaptive beam combining module to form M independent optical signals. These M optical signals are then directly or coherently detected, converting them into M electrical signals, which are then electrically synthesized. This method not only improves communication stability but also ensures the independence of the electrically synthesized signals.

Description

Technical Field

[0001] This invention relates to the technical field of MIMO free-space optical communication, and specifically to a multi-aperture receiving method for space optical communication that integrates optics and electronics. Background Technology

[0002] Free-space optical communication (FSOC) is favored for its exceptionally high speed and energy efficiency. Compared to millimeter-wave communication, FSOC offers higher bandwidth and lower power consumption. Compared to fiber optic communication, the high bandwidth of FSOC is unaffected by inter-symbol interference caused by fiber dispersion. However, low-order aberrations in the atmosphere, such as the first and second-order Zernike aberrations, can limit the reception performance of FSOC, increasing the bit error rate and even causing communication interruptions. Employing a multi-aperture receiving scheme to receive optical signals and correct for the first and second-order Zernike aberrations can effectively reduce the probability of interruptions and improve communication performance.

[0003] Currently, multi-channel sub-signal combining methods in multi-aperture receiver schemes for space optical communication mainly fall into two categories: electrical combining and optical combining. Electrical combining methods include analog combining methods represented by combiners and digital combining methods represented by algorithms such as Maximum Ratio Combining (MRC), Equal Gain Combining (EGC), and Selective Combining (SC). However, electrical combining requires a separate detector for each channel and demands that each sub-channel be independent, resulting in significant energy waste in the receiving plane. Optical combining performs phase compensation on multiple input optical signals, pre-combining a single optical signal before demodulation. Optical combining can effectively increase the power of the optical signal, enhance the optical signal-to-noise ratio in highly turbulent environments, and suppress optical flicker, making it a feasible solution for future ultra-high throughput communication requirements.

[0004] However, considering the current electrical combining method, the performance only improves with the increase of the number of sub-apertures when the sub-apertures are independent. Therefore, how to improve the receiving efficiency of multi-aperture antennas while ensuring the independence of the electrical combining signals is a problem that needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a multi-aperture receiving method for space optical communication that integrates optical and electrical technologies, thereby solving the technical problem of how to ensure the independence of electrically synthesized signals in multi-aperture receiving.

[0006] This invention provides a multi-aperture receiving method for space optical communication that integrates optical and electrical technologies, comprising:

[0007] S1. Determine the total receiving area based on the aperture size, communication link length, and turbulence intensity of the closely packed multi-aperture optical antenna;

[0008] S2. The number of optical beam combiner sub-apertures is intelligently adjusted by combining atmospheric refractive index structure constant, communication link length, signal light wavelength and channel correlation coefficient to ensure that the combined optical signals are independent of each other, and the optical signals are coupled and received and the first and second order Zernike aberrations are corrected based on the densely packed multi-aperture optical antenna with a determined receiving area and number of sub-apertures.

[0009] S3. The optical signal is split by an optical beam splitter. Part of the optical signal is input to the coupled energy photodetector and converted into a voltage or current feedback signal, which is then input to the control module. The energy of the other part of the optical signal is input to the N×1 adaptive beam combining module.

[0010] S4. Based on the intelligent adjustment of N×M sub-apertures, the optical signal is coherently combined into one optical signal through an N×1 adaptive beam combining module, and finally a total of M independent optical signals are formed.

[0011] S5. Directly or coherently detect the M optical signals, convert them into M electrical signals, and output the M electrical signals as a single electrical signal through electrical synthesis, and then perform decision demodulation on the electrical signal.

[0012] Optionally, the close-packed multi-aperture optical antenna includes:

[0013] The densely packed multi-aperture optical antenna uses an adaptive fiber coupler array or an on-chip phased array to achieve the beam splitting and combining function of the optical path.

[0014] Optionally, the number of optical combiner apertures can be intelligently adjusted by combining the atmospheric refractive index structure constant, communication link length, signal light wavelength, and channel correlation coefficient, including:

[0015] When the correlation coefficient between two sub-apertures is less than 1 / e 2 The channel correlation coefficient between two points on the receiving plane of the densely packed multi-aperture optical antenna can be considered as an independent channel:

[0016]

[0017] Where i and j represent two sub-apertures, s ij The distance between the centers of the two sub-apertures. These are the scintillation indices at sub-apertures i and j, respectively, and C ij The covariance coefficient between the two sub-apertures.

[0018] Optionally, the method of intelligently adjusting the number of optical combiner apertures by combining atmospheric refractive index structure constant, communication link length, signal light wavelength, and channel correlation coefficient further includes:

[0019] The covariance of irradiance is a function of distance s. In a weakly turbulent environment, the covariance function of light intensity is:

[0020]

[0021] In a strongly turbulent environment, the covariance function of light intensity is:

[0022]

[0023]

[0024] in, It is the Rytov variance, and L is the communication link length.

[0025] Optionally, the coupled energy photodetector includes:

[0026] Photon detectors, photodiodes, phototransistors, avalanche photodiodes, or photomultiplier tubes are used to convert optical signals into voltage or current signals.

[0027] Optionally, the N×1 adaptive beam combining module includes:

[0028] The N×1 adaptive beam combining module consists of a combining phase modulator, a directional coupler, a combining photodetector, and a combining piston aberration controller, and is used to compensate for piston aberrations between adaptive fiber coupler arrays.

[0029] Optionally, the step of synthesizing electrical signals from the M channels includes:

[0030] The M-channel electrical signals are synthesized using equal gain combining and maximum signal-to-noise ratio combining algorithms.

[0031] Optionally, the adaptive fiber coupler array includes:

[0032] The adaptive fiber coupler array can be arranged in a triangular, square, hexagonal, circular, or ring-shaped manner; and the overall receiving and transmitting apertures can be increased by increasing the number of adaptive fiber couplers.

[0033] Optionally, the control module includes:

[0034] Multi-channel adaptive fiber couplers are used to generate output control voltages using stochastic gradient descent, dithering, deep learning, or reinforcement learning algorithms.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] By intelligently adjusting the number of optical combiner apertures, energy waste caused by aperture independence is avoided, enabling the system to cope with different atmospheric turbulence conditions and improve communication stability. Furthermore, through a multi-aperture receiving method that integrates optical and electrical synthesis, the independence of the electrical synthesized signal is ensured in advance using optical coherent beam combining. This reduces the complexity of the electrical signal processing section when expanding the aperture array to a larger scale with more elements. Additionally, optical synthesis enhances the light intensity of the single-path detection signal, allowing for accurate demodulation of the modulated optical signal even under low signal-to-noise ratio conditions using the electrical synthesis algorithm. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the process of the present invention;

[0040] Figure 2 This is a schematic diagram of the overall photoelectric synthesis scheme in this invention;

[0041] Figure 3 This is a schematic diagram of the spatial diversity array distribution within the same receiving range in this invention;

[0042] Figure 4 This is a general schematic diagram of the optical synthesis scheme in this invention;

[0043] Figure 5 This is a schematic diagram of the overall electrical synthesis scheme in this invention;

[0044] Figure 6 This is a schematic diagram illustrating the influence of the antenna receiving aperture and the number of sub-apertures on the optical signal scintillation index in the vertical link of this invention.

[0045] Figure 7 This is a schematic diagram illustrating the influence of the number of sub-apertures within the same receiving range in the horizontal link on turbulence suppression performance in this invention.

[0046] Figure 8 This is a schematic diagram of the synthesis path of each received signal in this invention;

[0047] Figure 9This diagram illustrates the comparison of interruption probabilities for different receiving schemes, including optical and electrical synthesis, electrical synthesis, and optical synthesis, under different channel lengths, obtained through simulation. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Functional units with the same reference numerals in the examples of this invention have the same and similar structures and functions.

[0049] See Figure 1 and Figure 2 This invention provides a multi-aperture receiving method for space optical communication that integrates optical and electrical technologies, comprising:

[0050] S1. Determine the total receiving area based on the aperture size, communication link length, and turbulence intensity of the closely packed multi-aperture optical antenna;

[0051] S2. The number of optical beam combiner sub-apertures is intelligently adjusted by combining atmospheric refractive index structure constant, communication link length, signal light wavelength and channel correlation coefficient to ensure that the combined optical signals are independent of each other, and the optical signals are coupled and received and the first and second order Zernike aberrations are corrected based on the densely packed multi-aperture optical antenna with a determined receiving area and number of sub-apertures.

[0052] S3. The optical signal is split by an optical beam splitter. Part of the optical signal is input to the coupled energy photodetector and converted into a voltage or current feedback signal, which is then input to the control module. The energy of the other part of the optical signal is input to the N×1 adaptive beam combining module.

[0053] S4. Based on the intelligent adjustment of N×M sub-apertures, the optical signal is coherently combined into one optical signal through an N×1 adaptive beam combining module, and finally a total of M independent optical signals are formed.

[0054] S5. Directly or coherently detect the M optical signals, convert them into M electrical signals, and combine the M electrical signals into a single electrical signal through electrical processing. Then, perform decision demodulation on the electrical signal.

[0055] In this embodiment, S1, the total receiving area is determined based on the aperture size of the closely packed multi-aperture optical antenna, the communication link length, and the turbulence intensity;

[0056] The total receiving area is determined based on the transmission path distance and atmospheric turbulence intensity; the size of the sub-aperture is determined based on the atmospheric refractive index structure constant, communication link length, and signal light wavelength; the arrangement pattern of the multi-aperture receiving array is determined based on the principle of close-packed distribution; and the antenna's receiving performance is evaluated based on the scintillation index of the optical signal and the average aperture coefficient.

[0057] The flicker index of an optical signal reflects the change in normalized light intensity. The flicker index is defined as:

[0058]

[0059] Where I represents the normalized light intensity, and the scintillation index is generally:

[0060]

[0061] Where Rytov variance It refers to the variance after taking the logarithm of the light intensity.

[0062] Communication links can be divided into satellite-to-ground vertical links and ground-to-ground horizontal links. The turbulence intensity of the entire link is the integral of the atmospheric refractive index structure constant along the path. According to the atmospheric stratification theory, atmospheric turbulence is more severe only in areas with large temperature differences near the Earth's surface. The turbulence intensity of the entire path of the ground-to-ground horizontal link is affected by the ground atmospheric conditions. Therefore, the turbulence intensity of vertical links and horizontal links are different.

[0063] refer to Figure 6 It can be seen that in a vertical link, if the total area D of the receiving aperture is changed... G In areas with strong turbulence When the aperture size increases from 0.1m to 1m, the scintillation index of a single-aperture receiver with K=1 decreases from 0.5767 to 0.3868, even in weak turbulence. At that time, the flicker index decreased from 0.0096 to 0.0070. Increasing the receiver aperture showed the most significant improvement in flicker suppression for a single-aperture receiver with one aperture. As the number of apertures gradually increased, increasing the area of ​​the receiver aperture had little effect on flicker suppression. Meanwhile, increasing the number of sub-apertures significantly reduced the flicker effect. When D... G When the value is 0.1m, K increases from 1 to 25. Under turbulent conditions, scintillation index It decreased from 0.0096 to 0.0004. turbulent conditions It decreased from 0.5767 to 0.0218; when D G When K = 1m, K increases from 1 to 25. Under turbulent conditions, It decreased from 0.0070 to 0.0004. turbulent conditions The value decreased from 0.3868 to 0.0213. Increasing the number of sub-apertures had a more significant aperture-average effect than increasing the receiver aperture. Therefore, it can be concluded that using multi-aperture receiving technology can achieve better flicker suppression within a smaller receiving area than with a single aperture and can determine the closest possible receiving area based on requirements.

[0064] For multi-aperture array antennas, the equivalent aperture size is D G For the equivalent diameter of a single large aperture, D is the sub-aperture size, and K is the number of sub-apertures. Aperture averaging effect refers to the phenomenon that increasing the area of ​​the receiving aperture increases the average power of the coupled optical power. We use the aperture averaging coefficient to characterize the antenna's turbulence suppression effect; the smaller the aperture averaging coefficient, the lower its scintillation index and the stronger its turbulence suppression effect. Increasing the receiving aperture D increases the average power but also introduces more severely distorted optical signals. In practice, the value of D / r0 is often used to determine the size of the receiving aperture. The larger the receiving aperture D, the stronger the turbulence and the smaller the atmospheric coherence length r0. The larger this value, the more severe the distortion of the coupled and detected optical signal. In a multi-aperture receiving scheme, D / r0≈1, and the equivalent aperture averaging coefficient for multi-aperture receiving is:

[0065]

[0066] As can be seen from the above formula, when the wavelength is constant, the aperture average coefficient depends only on the aperture size and the path length. (Reference) Figure 7 Total reception range D in the horizontal link G The aperture average coefficient at 0.4m shows that the more sub-apertures an antenna has, the better its turbulence suppression effect under different turbulence intensities. However, in practical receivers, the number of sub-apertures cannot be increased indefinitely, as the subsequent complex signal processing modules and the introduction of noise will reduce the signal-to-noise ratio of the detector.

[0067] S2. The number of optical beam combiner sub-apertures is intelligently adjusted by combining the atmospheric refractive index structure constant, communication link length, signal light wavelength and channel correlation coefficient to ensure that the combined optical signals are independent of each other. Based on the densely packed multi-aperture optical antenna with a determined receiving area and number of sub-apertures, the optical signals are coupled and received and the first and second order Zernike aberrations are corrected.

[0068] Considering the electrical combining method, performance only improves with the increase of the number of sub-apertures when they are independent. Therefore, the focus of this scheme is on the flexible modification of the independent region. The spacing and number of sub-apertures for coherent combining, i.e., the optical beam combining region, are determined. This region is related to the atmospheric refractive index structure constant, the communication link length, and the atmospheric coherence length r0 determined by the signal light wavelength. Detailed information on determining the coherent combining region of the receiving sub-apertures is as follows:

[0069] The formula for calculating the atmospheric coherence length r0 is:

[0070]

[0071] Where r0 is the atmospheric coherence length, λ is the atmospheric refractive index structure constant, L is the communication link length, k is the wave number, k = 2π / λ, and λ is the wavelength, which corresponds to the diffraction-limited diameter distorted by atmospheric turbulence. When the telescope aperture is larger than this parameter, the imaging resolution no longer increases with the increase of the receiver aperture.

[0072] In current multi-aperture receiving antenna designs, sub-apertures are considered independent if the spacing between them is greater than the coherence length. This theory applies to moderate and weak turbulence. In strong turbulence, r0 decreases, while the correlation coefficient between two points at the same distance on the receiving plane increases. When correlation exists between sub-apertures, this correlation coefficient should be considered. Specifically, when the correlation coefficient between two observation points (two sub-apertures) on the receiving plane decreases to 1 / e... 2 When the distance is zero, it can be considered as two independent points, and this distance is named the correlation width of the light intensity on the receiving surface, with the correlation width number p. c This refers to the minimum spacing between two sub-apertures that are a certain distance apart, ensuring that their light intensity attenuation remains independent. The sub-aperture spacing of a multi-aperture receiver array antenna must be greater than the correlation width p at the laser arrival plane. c Only then can they be considered as mutually independent channels. Therefore, the channel correlation coefficient of the two sub-apertures in the densely packed multi-aperture optical antenna is:

[0073]

[0074] Where i and j represent two sub-apertures, s ij The distance between the centers of the two sub-apertures. These are the scintillation indices at sub-apertures i and j, respectively, and C ij The covariance coefficient between the two sub-apertures.

[0075] The covariance of irradiance is a function of distance s. In a weakly turbulent environment, the covariance function of light intensity is:

[0076]

[0077] In a strongly turbulent environment, the covariance function of light intensity is:

[0078]

[0079] in, It is the Rytov variance, and L is the communication link length.

[0080] Using the channel correlation model above, the impact of aperture spacing and number on the performance of multi-aperture receiving antennas can be accurately estimated under all turbulence intensities. The Rytov variance reflects the turbulence intensity, and ρ is obtained. c The relationship between r0 and turbulence intensity shows that the coherence width increases with increasing turbulence, while the atmospheric coherence length decreases. Based on existing experience, the spacing between sub-apertures should be within the relevant width ρ. c Nearby, the diameter should be within the coherence length scale. For multi-aperture receivers, the receiver area first needs to be fixed, determined by the aperture diameter, communication link length, turbulence intensity, etc., and then the aperture spacing and number of sub-apertures are calculated based on the turbulence suppression effect of the multi-aperture receiving antenna.

[0081] For fixed-link communication, the more sub-apertures in the receiving area, the more significant the turbulence mitigation effect after optical combining. Considering that the optical signals must be independent in the electrical combining method, this scheme uses the center distance of each optical coherent beam combining module as a reference to ensure the independence of electrical combining. By changing the size of the optical combining area, it can adapt to different turbulence conditions, while avoiding energy waste caused by excessively large sub-aperture spacing.

[0082] S3. The optical signal is split by an optical beam splitter. Part of the optical signal is input to the coupled energy photodetector and converted into a voltage or current feedback signal, which is then input to the control module. The energy of the other part of the optical signal is input to the N×1 adaptive beam combining module.

[0083] The optical beam splitter can be selected as needed, such as a 95:5 or 98:2 optical beam splitter. If a 95:5 optical beam splitter is used, 5% of the optical signal is input to the coupled energy photodetector and converted into a voltage or current feedback signal, which is then input to the control module. The remaining 95% of the optical signal is input to the N×1 adaptive beam combining module. The coupled energy photodetector uses a photon detector, photodiode, phototransistor, avalanche photodiode, or photomultiplier tube to convert the optical signal into a voltage or current signal. The coupled optical power of a single aperture should be higher than the sensitivity of the detector, and the operating wavelength range of the photodetector should cover the wavelength of the signal laser beam. The control module uses a multi-channel adaptive fiber coupling array controller, which generates an output control voltage using at least a stochastic gradient descent algorithm, a dithering algorithm, a deep learning algorithm, or a reinforcement learning algorithm. The control voltage applied to the phase modulator is used to achieve adaptive optical coherent combining, and the control voltage applied to the receiving coupling array is used to adaptively improve the coupling efficiency of spatial light.

[0084] S4. Based on intelligent adjustment of N×M sub-apertures, the optical signal is coherently combined into one optical signal through an N×1 adaptive beam combining module, ultimately forming a total of M independent optical signals.

[0085] An adaptive beamforming module based on phase compensation combines N optical signals into a single signal using a binary tree cascade approach. It selects a directional coupler with a corresponding splitting ratio based on the input light intensity ratio for coherent beamforming. The N×1 adaptive beamforming module consists of a combining phase modulator, a directional coupler, a combining photodetector, and a combining piston aberration controller, which compensates for piston aberrations between adaptive fiber coupler arrays. The phase modulator performs phase modulation on each received sub-signal, and after wavelength-scale phase compensation, inputs it to the coupler for coherent beamforming. Path selection is based on the correlation width p on the receiving surface. c The change in the number of sub-paths of coherent synthesis alters the path of the signal controlled by the optical switch, connecting to a coupler to continue coherent synthesis, or connecting to a photodetector to convert it into an electrical signal for digital demodulation; the synthesis piston aberration controller receives the electrical signal from the synthesis coupling energy photodetector and uses an optimized control algorithm to generate an output control voltage.

[0086] S5. Directly or coherently detect the M optical signals, convert them into M electrical signals, and combine the M electrical signals into a single electrical signal through electrical processing. Then, perform decision demodulation on the electrical signal.

[0087] See Figure 3The adaptive fiber coupler array can be arranged in a triangular, square, hexagonal, circular, or ring-shaped manner. At the same time, the optical combination area distribution of the hexagonal array and the combination model distribution of the square array, with the sub-apertures closely arranged on the receiving end face, can also increase the receiving area by stacking array modules.

[0088] See Figure 4 This demonstrates the overall scheme of the optical synthesis method. Figure 4 The correction of the first and second order Zernike aberrations can be achieved by using the optical power intensity output by a single-path coupled optical signal or an optical synthesis module as the performance index to perform closed-loop control of the corresponding optical signal aperture adaptive fiber coupler.

[0089] See Figure 5 This demonstrates the overall scheme of the electrosynthesis method. Figure 5 The optical signal is converted into an electrical signal and then electrically synthesized.

[0090] See Figure 6 This demonstrates the scintillation index of different aperture numbers under different aperture sizes in a vertical link.

[0091] See Figure 7 This study demonstrates the effect of different numbers of sub-apertures on turbulence suppression when the diameter of the multi-aperture receiving antenna is 0.4m, under different turbulence intensities of the horizontal link.

[0092] See Figure 8 In cases of weak turbulence, four sub-aperture regions are used as one optical coherent beam combining region, outputting one synthesized optical signal, ultimately forming 16 independent optical signals, which are then converted into electrical signals and electrically synthesized. In cases of strong turbulence, the coherence width is larger, and 16 sub-apertures are used as one optical beam combining region. Optical switches control the light propagation path, continuing optical coherent beam combining to form four independent optical signals, which are then converted into four independent electrical signals and electrically synthesized.

[0093] See Figure 9 The communication link lengths of the first, second, and third columns are 1km, 3km, and 5km, respectively. To verify the beam combining effect of this invention, simulations were used to compare the interruption probabilities of a single large-aperture optical and electrical combined scheme with a single electrical combined scheme under different channel lengths. The simulations used D... GTaking a receiving range of 0.4m as an example, within the same receiving range, the fewer the number of sub-apertures, the larger the diameter of a single closely packed sub-aperture. When the number of sub-apertures is 1, 4, 16, and 64, the corresponding single sub-aperture sizes are 0.4m, 0.2m, 0.1m, and 0.05m, respectively. Taking a receiving array arrangement with the most sub-apertures (64 (8x8) elements) as an example, the N×M optical and electrical synthesis region channel divisions are 1×64, 4×16, 16×4, and 64×1, respectively. The magnitude of represents the intensity of turbulence. It is evident that under different turbulence intensities, the probability of interruption of electrical synthesis is low in weak turbulence, while the probability of interruption of optical synthesis is low in strong turbulence. The interruption probability of optical and electrical synthesis between strong and weak turbulence is consistently the lowest.

[0094] See Figure 9 The results show the comparison of different receiving schemes, including optical and electrical combined reception, electrical combined reception, and optical combined reception. This invention intelligently adjusts the number of apertures in the optical combiner, avoiding energy waste caused by independent apertures, and can cope with different atmospheric turbulence conditions, improving communication stability. Furthermore, through multi-aperture reception using optical and electrical combined reception, the independence of the electrical combined signal is guaranteed by pre-emptively using optical coherent beam combining. This reduces the complexity of the electrical signal processing section when expanding to large-scale aperture arrays with more elements. Additionally, optical combined reception increases the light intensity of a single-path detection signal, enabling the correct demodulation of the modulated optical signal even under low signal-to-noise ratio conditions using electrical combined reception.

[0095] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0096] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A multi-aperture receiving method for space optical communication that integrates optical and electrical technologies, characterized in that, include: S1. Determine the total receiving area based on the aperture size, communication link length, and turbulence intensity of the closely packed multi-aperture optical antenna; S2. The number of optical beam combiner sub-apertures is intelligently adjusted based on the atmospheric refractive index structure constant, communication link length, signal wavelength, and channel correlation coefficient to ensure that the combined optical signals are independent of each other, including when the correlation coefficient between two sub-apertures is less than... The channel correlation coefficient between two points on the receiving plane of the densely packed multi-aperture optical antenna can be considered as an independent channel: , in, These represent two sub-apertures, The distance between the centers of the two sub-apertures. They are Scintillation index at the two sub-apertures The covariance coefficient between two sub-apertures is based on the irradiance covariance, which is the distance. In a weakly turbulent environment, the covariance function of light intensity is: , In a strongly turbulent environment, the covariance function of light intensity is: ， ， in, Let Rytov variance be the variance. L For the length of the communication link, As a hypergeometric function, the turbulence intensity is reflected by the Rytov variance, and thus obtained. and The correlation width increases with the increase of turbulence intensity, and the atmospheric coherence length... The aperture spacing and the number of sub-apertures are calculated based on the turbulence suppression effect of the multi-aperture receiving antenna. The optical signal is coupled and received and the first and second order Zernike aberrations are corrected based on the densely packed multi-aperture optical antenna with a determined receiving area and the number of sub-apertures. S3. The optical signal is split by an optical beam splitter. Part of the optical signal is input to the coupled energy photodetector and converted into a voltage or current feedback signal, which is then input to the control module. The energy of the other part of the optical signal is input to the N×1 adaptive beam combining module. S4. Based on the intelligent adjustment of N×M sub-apertures, the optical signal is coherently combined into one optical signal through an N×1 adaptive beam combining module, and finally a total of M independent optical signals are formed. S5. Directly or coherently detect the M optical signals, convert them into M electrical signals, and combine the M electrical signals into a single electrical signal through electrical processing. Then, perform decision demodulation on the electrical signal.

2. The optical and electrical integrated multi-aperture receiving method for space optical communication as described in claim 1, characterized in that, The densely packed multi-aperture optical antenna includes: The densely packed multi-aperture optical antenna uses an adaptive fiber coupler array or an on-chip phased array to achieve the beam splitting and combining function of the optical path.

3. The optical and electrical integrated multi-aperture receiving method for space optical communication as described in claim 1, characterized in that, The coupled energy photodetector includes: Photon detectors, photodiodes, phototransistors, avalanche photodiodes, or photomultiplier tubes are used to convert optical signals into voltage or current signals.

4. The space optical communication multi-aperture receiving method that integrates optics and electronics as described in claim 1, characterized in that, The N×1 adaptive beam combining module includes: The N×1 adaptive beam combining module consists of a combining phase modulator, a directional coupler, a combining photodetector, and a combining piston aberration controller, and is used to compensate for piston aberrations between adaptive fiber coupler arrays.

5. The optical and electrical integrated multi-aperture receiving method for space optical communication as described in claim 1, characterized in that, The electrical signal synthesis of the M-channel electrical signals includes: The electrical signals of the M channels are synthesized using analog or digital merging methods.

6. The optical and electrical integrated multi-aperture receiving method for space optical communication as described in claim 2, characterized in that, The adaptive fiber coupler array includes: The adaptive fiber coupler array can be arranged in a triangular, square, hexagonal, circular, or ring-shaped manner; and the overall receiving and transmitting apertures can be increased by increasing the number of adaptive fiber couplers.

7. The optical and electrical integrated multi-aperture receiving method for space optical communication as described in claim 1, characterized in that, The control module includes: A multi-channel adaptive fiber coupler array controller is used to generate output control voltage using stochastic gradient descent, dithering, deep learning, or reinforcement learning algorithms.

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