Multi-aperture coherent synthesis laser communication system and method based on circular offset keying modulation

Abstract

The present invention provides a multi-aperture coherent synthesis laser communication system and method based on circular offset keying modulation, wherein the method is applied to a multi-aperture coherent synthesis laser communication system based on circular offset keying modulation including a FSOC transmitter and a multi-aperture space diversity receiver, and the method includes: the FSOC transmitter generates FSOC signal light, CPolSK modulates the FSOC signal light to obtain emission light, and sends the emission light to the multi-aperture space diversity receiver; the multi-aperture space diversity receiver receives the emission light, adaptively couples the emission light and coherently synthesizes it to obtain a multi-aperture coherent synthesis laser, and demodulates and outputs the multi-aperture coherent synthesis laser. The present invention can achieve efficient and stable communication under complex atmospheric conditions and optimize the performance of the FSOC system under complex atmospheric conditions. The present invention adopts CPolSK modulation technology and multi-aperture coherent synthesis technology to effectively improve the anti-turbulence capability of the FSOC system.

Description

Technical Field

[0001] The present invention relates to the technical field of free space optical communication, and in particular to a multi-aperture coherent synthesis laser communication system and method based on circularly offset keying modulation. Background Art

[0002] As an important communication method, free space optical communication (FSOC) is favored by people because of its advantages such as large data transmission volume, rapid transmission and high transmission accuracy. However, the performance of FSOC system is largely limited by the wavefront distortion caused by atmospheric turbulence. This distortion can lead to a series of problems such as spot drift, light intensity flicker and signal depth attenuation, which significantly increases the bit error rate of the system and may even lead to the interruption of communication link in severe cases. Although the use of adaptive optics (AO) technology and multi-aperture spatial diversity receiving system can alleviate these problems to a certain extent, their performance is limited under strong turbulence conditions. Summary of the invention

[0003] Based on this, it is necessary to provide a multi-aperture coherent synthesis laser communication system and method based on circular offset keying modulation to address the above technical problems.

[0004] The multi-aperture coherent synthesis laser communication method based on circular offset keying modulation is applied to a multi-aperture coherent synthesis laser communication system based on circular offset keying modulation including a FSOC transmitter and a multi-aperture space diversity receiver, and comprises the following steps:

[0005] The FSOC transmitter generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver;

[0006] The multi-aperture spatial diversity receiver receives the emission light, performs adaptive coupling and coherent synthesis on the emission light to obtain multi-aperture coherent synthesis laser light, and demodulates and outputs the multi-aperture coherent synthesis laser light.

[0007] In one of the embodiments, the FSOC transmitter includes: a laser transmitter, a first PBS, a first PBC, a first QWP, a fiber amplifier, and a collimator;

[0008] The laser transmitter emits FSOC signal light, and the FSOC signal light passes through the first PBS to obtain two mutually orthogonal first polarized lights;

[0009] Phase modulate any one beam of first polarized light to obtain modulated polarized light, and send the modulated polarized light and another beam of first polarized light to the first PBC;

[0010] The first PBC receives the modulated polarized light and another first polarized light to obtain a first linear polarized light, and sends the first linear polarized light to the first QWP;

[0011] The first QWP receives the first linearly polarized light to obtain a first circularly polarized light, and sends the first circularly polarized light to the optical fiber amplifier;

[0012] The optical fiber amplifier amplifies the first circularly polarized light to obtain processed circularly polarized light, and sends the processed circularly polarized light to the collimator to obtain emitted light.

[0013] In one embodiment, a multi-aperture spatial diversity receiver includes: an adaptive fiber coupler array, a plurality of first phase modulators, a plurality of second QWPs, a plurality of second PBSs, a plurality of second PBCs, a first photodetector, a second photodetector, a first amplifier, a second amplifier, a first subtractor, and a first piston phase error control module;

[0014] The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the first phase modulator through the coupling fiber;

[0015] The first phase modulator corresponds to the second QWP one by one, receives the diversity signal light, performs piston phase error compensation on the diversity signal light to obtain a first co-phase circularly polarized light, and sends the first co-phase circularly polarized light to the second QWP;

[0016] The second QWP receives the first co-phase circularly polarized light to obtain a second linearly polarized light, and sends the second linearly polarized light to the second PBS;

[0017] The second PBS receives the second linearly polarized light to obtain mutually orthogonal first polarization state light, and sends the first polarization state light to the second PBC;

[0018] The second PBC performs coherent synthesis on the light of the same first polarization state to obtain two first synthesized light beams, sends any one of the first synthesized light beams to the first photodetector, and sends the other first synthesized light beam to the second photodetector;

[0019] The first photodetector receives the arbitrary first synthetic light beam, detects the beam intensity of the arbitrary first synthetic light beam, and sends the arbitrary first synthetic light beam to the first amplifier;

[0020] The second photodetector receives the other first synthetic light beam, detects the beam intensity of the other first synthetic light beam, and sends the other first synthetic light beam to the second amplifier;

[0021] The first amplifier amplifies the signal of any one of the first synthetic light beams to obtain a first amplified signal, and sends the first amplified signal to the first subtractor;

[0022] The second amplifier amplifies the signal of the other first synthetic light beam to obtain a second amplified signal, and sends the second amplified signal to the first subtractor;

[0023] The first subtractor receives the first amplified signal and the second amplified signal to obtain a first differential signal, and demodulates the first amplified signal and the second amplified signal according to the first differential signal to obtain a first demodulated multi-aperture coherent synthesis laser;

[0024] The first piston phase error control module is arranged between the first subtractor and the first phase modulator, and adjusts the piston phase error between different diversity signal lights by the first phase controller according to the first amplified signal and the second amplified signal in the first subtractor.

[0025] In one embodiment, the multi-aperture spatial diversity receiver includes: an adaptive fiber coupler array, a plurality of third QWPs, a plurality of second phase modulators, a plurality of third PBSs, a plurality of third PBCs, a third photodetector, a fourth photodetector, a third amplifier, a fourth amplifier, and a second subtractor;

[0026] The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the third QWP through the coupling fiber;

[0027] The third QWP receives the diversity signal light to obtain a third linearly polarized light, and sends the third linearly polarized light to the third PBS;

[0028] The third PBS receives the third linearly polarized light to obtain mutually orthogonal second polarization state light, and sends the second polarization state light to the second phase modulator;

[0029] The second phase modulator receives the second polarization state light, performs piston phase error compensation on the second polarization state light to obtain second co-phase circularly polarized light, and sends the second co-phase circularly polarized light to the third PBC;

[0030] The third PBC performs coherent synthesis on the same second co-phase circularly polarized light to obtain two second synthesized light beams, sends any one of the second synthesized light beams to the third photodetector, and sends the other second synthesized light beam to the fourth photodetector;

[0031] The third photodetector receives the arbitrary second composite light beam, detects the beam intensity of the arbitrary second composite light beam, and sends the arbitrary second composite light beam to the third amplifier;

[0032] The fourth photodetector receives the other second composite light beam, detects the beam intensity of the other second composite light beam, and sends the other second composite light beam to the fourth amplifier;

[0033] The third amplifier amplifies the signal of any one of the second synthetic light beams to obtain a third amplified signal, and sends the third amplified signal to the second subtractor;

[0034] The fourth amplifier amplifies the signal of the other second synthetic light beam to obtain a fourth amplified signal, and sends the fourth amplified signal to the second subtractor;

[0035] The second subtractor receives the third amplified signal and the fourth amplified signal to obtain a second differential signal, and demodulates the third amplified signal and the fourth amplified signal according to the second differential signal to obtain a second demodulated multi-aperture coherent synthesis laser.

[0036] In one of the embodiments, the multi-aperture spatial diversity receiver further includes: a plurality of third phase modulators;

[0037] The third phase modulator is arranged between the third PBCs and on the propagation path of the third synthetic light beam, and performs piston phase error compensation on the third synthetic light beam.

[0038] In one of the embodiments, further comprising: a plurality of fourth QWPs;

[0039] The fourth QWP is disposed between the third PBC and the third photodetector and the fourth photodetector, receives the second synthetic light beam to obtain a fourth linearly polarized light, and sends the fourth linearly polarized light to the third photodetector and the fourth photodetector.

[0040] In one of the embodiments, it further includes: a fourth photodetector, a tilt aberration control module and a high voltage amplifier;

[0041] The aperture division is performed on the emission light to obtain diversity signal light, and then the method further comprises:

[0042] The fourth photodetector receives the diversity signal light, detects the beam intensity of the diversity signal light, and sends the diversity signal light to the tilt aberration control module;

[0043] The tilt aberration control module receives the diversity signal light, generates a random control voltage according to the diversity signal light, sends the random control voltage to the high-voltage amplifier to obtain an amplified voltage, and sends the amplified voltage to the adaptive fiber coupler array to ensure that the fiber coupling efficiency of the diversity signal light reaches the maximum power.

[0044] In one of the embodiments, it further includes: a second piston phase error control module and a third piston phase error control module;

[0045] The second piston phase error control module is arranged between the third amplifier and the second phase modulator, and adjusts the second piston phase error of the second phase controller between different second co-phase circularly polarized lights according to the third amplified signal in the third amplifier;

[0046] The third piston phase error control module is arranged between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error between different second co-phase circularly polarized lights by the second phase controller according to the fourth amplified signal in the fourth amplifier.

[0047] In one of the embodiments, it further includes: a fourth piston phase error control module and a fifth piston phase error control module;

[0048] The fourth piston phase error control module is arranged between the third amplifier and the third phase modulator, and adjusts the third piston phase error between different third synthetic light beams by the third phase controller according to the third amplified signal in the third amplifier;

[0049] The third piston phase error control module is arranged between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error between different third synthetic light beams by the third phase controller according to the fourth amplified signal in the fourth amplifier.

[0050] A multi-aperture coherent synthesis laser communication system based on circular deviation keying modulation includes: a FSOC transmitter and a multi-aperture spatial diversity receiver;

[0051] The FSOC transmitter generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver;

[0052] The multi-aperture spatial diversity receiver receives the emission light, performs adaptive coupling and coherent synthesis on the emission light to obtain multi-aperture coherent synthesis laser light, and demodulates and outputs the multi-aperture coherent synthesis laser light.

[0053] Compared with the prior art, the advantages and beneficial effects of the present invention are: the present invention can achieve efficient and stable communication under complex atmospheric conditions, and optimize the performance of the FSOC system under complex atmospheric conditions, especially under strong atmospheric turbulence. The present invention adopts CPolSK modulation technology and multi-aperture coherent synthesis technology, and realizes signal light CPolSK modulation and coherent polarization synthesis reception and demodulation through a specially designed optical antenna component, effectively improving the anti-turbulence capability of the FSOC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of a flow chart of a multi-aperture coherent synthesis laser communication method based on circular offset keying modulation in one embodiment;

[0055] Figure 2 A schematic diagram of a FSOC transmitter processing flow in one embodiment;

[0056] Figure 3 A schematic diagram of a processing flow of a multi-aperture spatial diversity receiver in one embodiment;

[0057] Figure 4 A schematic diagram of the installation structure of a second phase modulator in one embodiment;

[0058] Figure 5 It is a schematic diagram of the installation structure of the third phase modulator in one embodiment;

[0059] Figure 6 A schematic diagram of a fourth QWP installation structure in an embodiment;

[0060] Figure 7 The figure is a schematic diagram of the structure of a multi-aperture coherent synthesis laser communication system based on circular offset keying modulation in one embodiment.

[0061] In the figure: 10-FSOC transmitter, 11-multi-aperture spatial diversity receiver, 100-laser transmitter, 101-first PBS, 102-first PBC, 103-first QWP, 104-fiber amplifier, 105-collimator, 110-adaptive fiber coupler array, 111-first phase modulator, 112-second QWP, 113-second PBS, 114-second PBC, 115-first photodetector, 116-second photodetector, 117-first amplifier, 118-second amplifier, 119-first subtractor, 110-first piston phase error control module, 112'-third QWP, 1110-second phase modulator, 112-second QWP, 113-second PBS, 114-second PBC, 115-first photodetector, 116-second photodetector, 117-first amplifier, 118-second amplifier, 119-first subtractor, 110-first piston phase error control module, 1110-third QWP, 1111-second phase modulator, 1112-second QWP, 1113-second PBS, 114-second PBC, 115-first photodetector, 116-second photodetector, 117-first amplifier, 118-second amplifier, 119-first subtractor, 110-first piston phase error control module, 1113-third QWP, 1114-second 11'-second phase modulator, 113'-third PBS, 114'-third PBC, 115'-third photodetector, 116'-fourth photodetector, 117'-third amplifier, 118'-fourth amplifier, 119'-second subtractor, 1111-fourth photodetector, 1112-tilt aberration control module, 1113-high voltage amplifier, 1114-fourth QWP, 1115-second piston phase error control module, 1116-third piston phase error control module, 1115'-fourth piston phase error control module, 1116'-fifth piston phase error control module, 1117-third phase modulator DETAILED DESCRIPTION

[0062] Before describing the specific embodiments of the present invention, the overall concept of the present invention is described as follows:

[0063] The present invention is mainly developed in the process of free space optical communication. At present, the performance of the FSOC system is largely limited by the wavefront distortion caused by atmospheric turbulence. This distortion can cause a series of problems such as spot drift, light intensity flicker and signal depth attenuation, significantly increasing the bit error rate of the system, and in severe cases may even lead to the interruption of the communication link. Although the use of adaptive optics (AO) technology and multi-aperture spatial diversity receiving systems can alleviate these problems to a certain extent, their performance is limited under strong turbulence conditions.

[0064] The selection and optimization of the modulation mode of the FSOC system has become a key breakthrough point for improving the system's ability to resist turbulence interference. The CPolSK (Circular Polarization Shift Keying) modulation mode is a modulation technology that uses the change of circular polarization state to transmit information, and realizes the encoding and transmission of information by changing the circular polarization state of the transmitted signal. Compared with traditional modulation methods, CPolSK modulation has better anti-turbulence performance. For example, under the same constraints, the SNR requirement of CPolSK modulation is 8dB lower than that of OOK modulation. However, to give full play to the potential of the CPolSK modulation mode, a special optical antenna system must be designed, including the design of special optical transmitters and receivers, etc., so as to further improve the anti-turbulence ability of the CPolSK modulation mode. Therefore, the present invention proposes a multi-aperture coherent synthesis laser communication method based on circular polarization keying modulation, which is applied to a multi-aperture coherent synthesis laser communication system based on circular polarization keying modulation, and by designing the corresponding FSO transmitter and multi-aperture spatial diversity receiver, the CPolSK modulation signal generation and reception in the atmospheric channel are realized, thereby improving the anti-turbulence performance of the communication system.

[0065] After introducing the overall concept of the present invention, in order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0066] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of this specification should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in one or more embodiments of this specification do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0067] For ease of understanding, the terms involved in the embodiments of the present invention are explained below:

[0068] FSOC: Free Space Optical Communications refers to the communication technology that uses light waves as carriers to transmit information in a vacuum or atmosphere. It can be divided into atmospheric optical communications, satellite-to-satellite optical communications, and satellite-to-ground optical communications.

[0069] CPolSK modulation: Circular polarization keying (PolSK) is a modulation technology that uses changes in circular polarization states to transmit information. It achieves information encoding and transmission by changing the circular polarization state of the transmitted signal.

[0070] PBC: Polarization beam combiner, based on the characteristics of polarized light, combines two mutually perpendicular polarized light beams (p-polarization and s-polarization) together.

[0071] PBS: Polarization beam splitter, also known as polarization beam splitter prism, is an optical device used to couple orthogonal linear polarized light in one optical fiber to two optical fibers for output.

[0072] QWP: A quarter wave plate is also called a "quarter retardation plate". When a certain wavelength of light is incident vertically, the phase difference between the outgoing ordinary light and the extraordinary light is 1 / 4 wavelength. In the optical path, it is often used to convert linear polarized light into circular polarized light or elliptically polarized light; or vice versa.

[0073] In one embodiment, Figure 1 As shown, a multi-aperture coherent synthesis laser communication method based on circular offset keying modulation is provided. The method is applied to a multi-aperture coherent synthesis laser communication system based on circular offset keying modulation including a FSOC transmitter 10 and a multi-aperture space diversity receiver 11, and includes the following steps:

[0074] Step S101: the FSOC transmitter generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver.

[0075] Specifically, the FSOC transmitter 10 generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, transmits the transmission light to be transmitted in the atmospheric channel, and sends the transmission light to the multi-aperture spatial diversity receiver 11 through the atmospheric channel.

[0076] On this basis, the FSOC transmitter includes: a laser transmitter, a first PBS, a first PBC, a first QWP, a fiber amplifier and a collimator;

[0077] The laser transmitter emits FSOC signal light, and the FSOC signal light passes through the first PBS to obtain two mutually orthogonal first polarized lights;

[0078] Phase modulate any one beam of first polarized light to obtain modulated polarized light, and send the modulated polarized light and another beam of first polarized light to the first PBC;

[0079] The first PBC receives the modulated polarized light and another first polarized light to obtain a first linear polarized light, and sends the first linear polarized light to the first QWP;

[0080] The first QWP receives the first linearly polarized light to obtain a first circularly polarized light, and sends the first circularly polarized light to the optical fiber amplifier;

[0081] The optical fiber amplifier amplifies the first circularly polarized light to obtain processed circularly polarized light, and sends the processed circularly polarized light to the collimator to obtain emitted light.

[0082] Specifically, Figure 2 As shown, in the FSOC transmitter 10, it includes: a laser transmitter 100, a first PBS 101, a first PBC 102, a first QWP 103, a fiber amplifier 104 and a collimator 105;

[0083] The FSOC signal light is sent through the laser transmitter 100. The FSOC signal light passes through the first PBS 101. The FSOC signal light rotated 45° with the optical axis is divided into two orthogonal X and Y first polarized light components. Any of the first polarized lights is phase modulated by the encoded data to rotate the laser phase by 0 or π. After passing through the first PBC 102 (polarization beam combiner), the two orthogonal signal lights are combined into first linear polarized lights with different polarization directions of 45° / -45°, which are converted into right / left first circularly polarized lights through the first QWP 103 (1 / 4 wave plate). The first circularly polarized light is sent to the optical fiber amplifier 104. After the optical fiber amplifier 104 amplifies the first circularly polarized light, the processed circularly polarized light is sent to the collimator 105 to obtain the emission light, which is then emitted through the collimator 105 to be transmitted in the atmospheric channel.

[0084] Step S102, the multi-aperture spatial diversity receiver receives the emission light, adaptively couples the emission light and coherently synthesizes it to obtain multi-aperture coherently synthesized laser light, and demodulates and outputs the multi-aperture coherently synthesized laser light.

[0085] Specifically, the multi-aperture spatial diversity receiver 11 receives the transmitted light, performs adaptive coupling on the transmitted light, and performs coherent synthesis on the transmitted light before demodulation and output.

[0086] In this embodiment, the multi-aperture spatial diversity receiver can not only identify the polarization state, but also has the function of multi-aperture coherent synthesis, thereby increasing the power of the received signal and reducing the degree of jitter. The multi-aperture spatial diversity receiving technology can realize efficient reception and demodulation of the signal light, and the signal light is demodulated and output after multi-aperture coherent synthesis to obtain the demodulated multi-aperture coherent synthesis laser.

[0087] On this basis, in one embodiment, the multi-aperture spatial diversity receiver includes: an adaptive fiber coupler array, a plurality of first phase modulators, a plurality of second QWPs, a plurality of second PBSs, a plurality of second PBCs, a first photodetector, a second photodetector, a first amplifier, a second amplifier, a first subtractor, and a first piston phase error control module;

[0088] The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the first phase modulator through the coupling fiber;

[0089] The first phase modulator corresponds to the second QWP one by one, receives the diversity signal light, performs piston phase error compensation on the diversity signal light to obtain a first co-phase circularly polarized light, and sends the first co-phase circularly polarized light to the second QWP;

[0090] The second QWP receives the first co-phase circularly polarized light to obtain a second linearly polarized light, and sends the second linearly polarized light to the second PBS;

[0091] The second PBS receives the second linearly polarized light to obtain mutually orthogonal first polarization state light, and sends the first polarization state light to the second PBC;

[0092] The second PBC performs coherent synthesis on the light of the same first polarization state to obtain two first synthesized light beams, sends any one of the first synthesized light beams to the first photodetector, and sends the other first synthesized light beam to the second photodetector;

[0093] The first photodetector receives the arbitrary first synthetic light beam, detects the beam intensity of the arbitrary first synthetic light beam, and sends the arbitrary first synthetic light beam to the first amplifier;

[0094] The second photodetector receives the other first synthetic light beam, detects the beam intensity of the other first synthetic light beam, and sends the other first synthetic light beam to the second amplifier;

[0095] The first amplifier amplifies the signal of any one of the first synthetic light beams to obtain a first amplified signal, and sends the first amplified signal to the first subtractor;

[0096] The second amplifier amplifies the signal of the other first synthetic light beam to obtain a second amplified signal, and sends the second amplified signal to the first subtractor;

[0097] The first subtractor receives the first amplified signal and the second amplified signal to obtain a first differential signal, and demodulates the first amplified signal and the second amplified signal according to the first differential signal to obtain a first demodulated multi-aperture coherent synthesis laser;

[0098] The first piston phase error control module is arranged between the first subtractor and the first phase modulator, and adjusts the piston phase error between different diversity signal lights by the first phase controller according to the first amplified signal and the second amplified signal in the first subtractor.

[0099] Specifically, Figure 3 As shown, the multi-aperture spatial diversity receiver 11 includes: an adaptive fiber coupler array 110, a plurality of first phase modulators 111, a plurality of second QWPs 112, a plurality of second PBSs 113, a plurality of second PBCs 114, a first photodetector 115, a second photodetector 116, a first amplifier 117, a second amplifier 118, a first subtractor 119 and a first piston phase error control module 1110.

[0100] The multi-aperture spatial diversity receiver 11 performs aperture segmentation on the received optical signal through a light cutting array to obtain multiple diversity signal light beams, and uses a control algorithm to couple the diversity signal light into the coupling optical fiber corresponding to the adaptive fiber coupler through the adaptive fiber coupler array 110.

[0101] The coupling optical fiber is correspondingly connected to a first phase modulator 111, which adopts a control algorithm to perform piston phase error compensation on the phase error between each optical signal with the strength of the differential signal as an evaluation standard, obtains a first co-phase circularly polarized light, and realizes phase alignment of the diversity signal.

[0102] The first phase modulator 111 first converts the co-phase circularly polarized light into the second linearly polarized light through the second QWP112 (1 / 4 wave plate), so that the co-phase circularly polarized light in the right / left direction is converted into the second linearly polarized light of 45° / -45°, and then the polarization direction of the second linearly polarized light is divided into orthogonal X and Y polarization directions by the second PBS113 (polarization beam splitter) to obtain the first polarization state light, and then the same first polarization state light is coherently polarized through the second PBC114 (polarization beam combiner) to be output as one beam of light, and a total of two first synthetic light beams are obtained.

[0103] The two first composite light beams are connected to the first photodetector 115 and the second photodetector 116 respectively, and the first photodetector 115 and the second photodetector 116 detect the intensity of the two first composite light beams corresponding to the 45° / -45° second linear polarized light. After passing through the first photodetector 115 and the second photodetector 116, the first composite light beam is converted from an optical signal to an electrical signal, and the two first composite light beams are sent to the first amplifier 117 and the second amplifier 118 respectively for electrical signal amplification. The first amplified signal and the second amplified signal obtained by amplifying the two beams can be used by the first subtractor 119 to generate a differential signal to realize the demodulation of the signal light of the CPolSK modulation mode.

[0104] The first piston phase error control module 1110 is disposed between the first subtractor 119 and the first phase modulator 111 , and adjusts the piston phase error between different diversity signal lights by the first phase controller 111 according to the first amplified signal and the second amplified signal in the first subtractor 119 .

[0105] On this basis, in one embodiment, the multi-aperture spatial diversity receiver includes: an adaptive fiber coupler array, a plurality of third QWPs, a plurality of second phase modulators, a plurality of third PBSs, a plurality of third PBCs, a third photodetector, a fourth photodetector, a third amplifier, a fourth amplifier, and a second subtractor;

[0106] The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the third QWP through the coupling fiber;

[0107] The third QWP receives the diversity signal light to obtain a third linearly polarized light, and sends the third linearly polarized light to the third PBS;

[0108] The third PBS receives the third linearly polarized light to obtain mutually orthogonal second polarization state light, and sends the second polarization state light to the second phase modulator;

[0109] The second phase modulator receives the second polarization state light, performs piston phase error compensation on the second polarization state light to obtain second co-phase circularly polarized light, and sends the second co-phase circularly polarized light to the third PBC;

[0110] The third PBC performs coherent synthesis on the same second co-phase circularly polarized light to obtain two second synthesized light beams, sends any one of the second synthesized light beams to the third photodetector, and sends the other second synthesized light beam to the fourth photodetector;

[0111] The third photodetector receives the arbitrary second composite light beam, detects the beam intensity of the arbitrary second composite light beam, and sends the arbitrary second composite light beam to the third amplifier;

[0112] The fourth photodetector receives the other second composite light beam, detects the beam intensity of the other second composite light beam, and sends the other second composite light beam to the fourth amplifier;

[0113] The third amplifier amplifies the signal of any one of the second synthetic light beams to obtain a third amplified signal, and sends the third amplified signal to the second subtractor;

[0114] The fourth amplifier amplifies the signal of the other second synthetic light beam to obtain a fourth amplified signal, and sends the fourth amplified signal to the second subtractor;

[0115] The second subtractor receives the third amplified signal and the fourth amplified signal to obtain a second differential signal, and demodulates the third amplified signal and the fourth amplified signal according to the second differential signal to obtain a second demodulated multi-aperture coherent synthesis laser.

[0116] Specifically, Figure 4 As shown, the multi-aperture spatial diversity receiver 11 can be composed of another structure, including: an adaptive fiber coupler array 110, a plurality of third QWPs 112', a second phase modulator 111', a plurality of third PBSs 113', a plurality of third PBCs 114', a third photodetector 115', a fourth photodetector 116', a third amplifier 117', a fourth amplifier 118' and a second subtractor 119'.

[0117] The multi-aperture spatial diversity receiver 11 performs aperture segmentation on the received optical signal through a light cutting array to obtain multiple diversity signal light beams, and uses a control algorithm to couple the diversity signal light into the coupling optical fiber corresponding to the adaptive fiber coupler through the adaptive fiber coupler array 110.

[0118] The coupling optical fiber is correspondingly connected to the third QWP112', and the second QWP112' (1 / 4 wave plate) is converted into a third linear polarized light, so that the co-phase circularly polarized light in the right / left direction is converted into a 45° / -45° third linear polarized light, and then the third linear polarized light is sent to the third PBS113' (polarization beam splitter), and the third PBS113' divides the polarization direction of the third linear polarized light into orthogonal X and Y polarization directions to obtain a second polarization state light, and then the second polarization state light is sent to the second phase modulator 111', the second phase modulator 111' receives the second polarization state light, performs piston phase error compensation on the second polarization state light, and obtains a second co-phase circularly polarized light, and then the same first polarization state light is coherently polarized through the third PBC114' (polarization beam combiner) to be output as a beam of light, and a total of two second synthetic light beams are obtained.

[0119] The two second composite light beams are connected to the third photodetector 115' and the fourth photodetector 116' respectively. The third photodetector 115' and the fourth photodetector 116' detect the intensity of the two second composite light beams corresponding to the third linear polarized light of 45° / -45°. After passing through the third photodetector 115' and the fourth photodetector 116', the second composite light beams are converted from optical signals into electrical signals. The two second composite light beams are sent to the third amplifier 117' and the fourth amplifier 118' respectively for electrical signal amplification. The third amplified signal and the fourth amplified signal obtained by amplifying the two beams can be used by the second subtractor 119' to generate a differential signal to realize the demodulation of the signal light of the CPolSK modulation mode.

[0120] On this basis, in one embodiment, it further includes: the multi-aperture spatial diversity receiver further includes: a plurality of third phase modulators;

[0121] The third phase modulator is arranged between the third PBCs and on the propagation path of the third synthetic light beam, and performs piston phase error compensation on the third synthetic light beam.

[0122] Specifically, Figure 5 As shown, the multi-aperture spatial diversity receiver 11 can also be constructed in this structure, where a secondary phase modulator, ie, a third phase modulator 1117 is arranged in the middle of the third PBC 114', and the third phase modulator 1117 performs piston phase error compensation on the third synthetic light beam.

[0123] In this embodiment, the multi-aperture spatial diversity receiver 11 can have a variety of structures. A first-level phase modulator can be set between the third PBS113' and the third PBC114', and on this basis, a second-level phase modulator can be set between the third PBS113' and the third PBC114' and between the third PBC114'. In addition, a multi-level phase modulator can be set. The structure is flexible and can meet complex optical transmission and processing requirements.

[0124] Providing the third phase modulator 1117 can further reduce phase noise and interference, and improve signal quality and transmission reliability.

[0125] On this basis, it also includes: It also includes: the fourth QWP;

[0126] The fourth QWP is disposed between the third PBC and the third photodetector and the fourth photodetector, receives the second synthetic light beam to obtain a fourth linearly polarized light, and sends the fourth linearly polarized light to the third photodetector and the fourth photodetector.

[0127] Specifically, Figure 6 As shown, the multi-aperture spatial diversity receiver 11 can also be constructed in this structure, where a fourth QWP 1114 is disposed between the third PBC 114' and the third photodetector 115' and the fourth photodetector 116'.

[0128] In this embodiment, the fourth QWP 1114 is disposed between the third PBC 114 ′ and the third photodetector 115 ′ and the fourth photodetector 116 ′, which can improve the transmission efficiency and stability of the signal.

[0129] On this basis, it also includes: a fourth photodetector, a tilt aberration control module and a high-voltage amplifier;

[0130] The aperture division is performed on the emission light to obtain diversity signal light, and then the method further comprises:

[0131] The fourth photodetector receives the diversity signal light, detects the beam intensity of the diversity signal light, and sends the diversity signal light to the tilt aberration control module;

[0132] The tilt aberration control module receives the diversity signal light, generates a random control voltage according to the diversity signal light, sends the random control voltage to the high-voltage amplifier to obtain an amplified voltage, and sends the amplified voltage to the adaptive fiber coupler array to ensure that the fiber coupling efficiency of the diversity signal light reaches the maximum power.

[0133] Specifically, after the emission light is aperture-split to obtain the diversity signal light, it is necessary to determine the coupling power intensity of the diversity signal light and couple the coupling optical fiber. The fourth photodetector 1111 receives the diversity signal light, detects the beam intensity of the diversity signal light, and sends the diversity signal light to the tilt aberration control module 1112.

[0134] The tilt aberration control module 1112 receives the diversity signal light, generates a random control voltage according to the diversity signal light, generates a control voltage signal, and sends the random control voltage to the high-voltage amplifier 1113. The high-voltage amplifier 1113 amplifies the random control voltage to obtain an amplified voltage, and sends the amplified voltage to the adaptive fiber coupler array 110, so that the fiber coupling efficiency of the diversity signal light reaches the optimal level in the whole process, and fiber coupling is performed.

[0135] On this basis, it also includes: a second piston phase error control module and a third piston phase error control module;

[0136] The second piston phase error control module is arranged between the third amplifier and the second phase modulator, and adjusts the second piston phase error of the second phase controller between different second co-phase circularly polarized lights according to the third amplified signal in the third amplifier;

[0137] The third piston phase error control module is arranged between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error between different second co-phase circularly polarized lights by the second phase controller according to the fourth amplified signal in the fourth amplifier.

[0138] Specifically, the second piston phase error control module 1115 and the third piston phase error control module 1116 are connected to the third amplifier 117' and the fourth amplifier 118' respectively, and adjust the second piston phase error of the second phase controller 111' between different second co-phase circularly polarized lights according to the third amplified signal and the fourth amplified signal.

[0139] On this basis, it also includes: a fourth piston phase error control module and a fifth piston phase error control module;

[0140] The fourth piston phase error control module is arranged between the third amplifier and the third phase modulator, and adjusts the third piston phase error between different third synthetic light beams by the third phase controller according to the third amplified signal in the third amplifier;

[0141] The third piston phase error control module is arranged between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error between different third synthetic light beams by the third phase controller according to the fourth amplified signal in the fourth amplifier.

[0142] Specifically, the fourth piston phase error control module 1115' and the fifth piston phase error control module 1116' are respectively connected to the third amplifier 117' and the fourth amplifier 118', and adjust the third piston phase error between different third synthetic beams by the second phase controller 111' according to the third amplified signal and the fourth amplified signal.

[0143] The multi-aperture coherent synthesis laser communication method based on circularly offset keying modulation provided by the present invention can realize efficient and stable communication under complex atmospheric conditions, and optimize the performance of the FSOC system under complex atmospheric conditions, especially under strong atmospheric turbulence. The present invention adopts CPolSK modulation technology and multi-aperture coherent synthesis technology, and realizes signal light CPolSK modulation and multi-aperture coherent synthesis reception and demodulation through a specially designed optical antenna component, effectively improving the anti-turbulence capability of the FSOC system.

[0144] It should be noted that the method of the embodiment of the present invention can be performed by a single device, such as a computer or a server. The method of this embodiment can also be applied in a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present invention, and the multiple devices will interact with each other to complete the described method.

[0145] It should be noted that some embodiments of the present invention are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0146] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present invention also provides a multi-aperture coherent synthesis laser communication system based on circular offset keying modulation.

[0147] refer to Figure 7 The multi-aperture coherent synthesis laser communication system based on circular offset keying modulation includes: a FSOC transmitter 10 and a multi-aperture spatial diversity receiver 11;

[0148] The FSOC transmitter 10 generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver 11;

[0149] The multi-aperture spatial diversity receiver 11 receives the emission light, performs adaptive coupling and coherent synthesis on the emission light to obtain multi-aperture coherent synthesis laser light, and demodulates and outputs the multi-aperture coherent synthesis laser light.

[0150] For the convenience of description, the above device is described as being divided into various modules according to their functions. Of course, when implementing the present invention, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0151] The device of the above embodiment is used to implement the corresponding multi-aperture coherent synthesis laser communication method based on circular offset keying modulation in any of the above embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0152] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0153] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0154] In addition, to simplify the description and discussion, and in order not to obscure the embodiments of the present invention, known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided figures. In addition, the devices may be shown in the form of block diagrams to avoid obscuring the embodiments of the present invention, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present invention will be implemented (i.e., these details should be fully within the scope of understanding of those skilled in the art). Where specific details (e.g., circuits) are set forth to describe exemplary embodiments of the present invention, it will be apparent to those skilled in the art that embodiments of the present invention may be implemented without these specific details or with variations in these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0155] Although the invention has been described in conjunction with specific embodiments of the invention, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0156] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-aperture coherent synthesis laser communication method based on circular deflection keying modulation, characterized in that: The invention is applied to a multi-aperture coherent synthesis laser communication system based on circular shift keying modulation, which includes a FSOC transmitter and a multi-aperture space diversity receiver; wherein the FSOC transmitter includes: a laser transmitter, a first PBS, a first PBC, a first QWP, a fiber amplifier and a collimator; The laser transmitter emits FSOC signal light, and the FSOC signal light passes through the first PBS to obtain two mutually orthogonal first polarized lights; Phase modulate any one beam of first polarized light to obtain modulated polarized light, and send the modulated polarized light and another beam of first polarized light to the first PBC; The first PBC receives the modulated polarized light and another first polarized light to obtain a first linear polarized light, and sends the first linear polarized light to the first QWP; The first QWP receives the first linearly polarized light to obtain a first circularly polarized light, and sends the first circularly polarized light to the optical fiber amplifier; The optical fiber amplifier amplifies the first circularly polarized light to obtain processed circularly polarized light, and sends the processed circularly polarized light to the collimator to obtain emitted light; The multi-aperture spatial diversity receiver comprises: an adaptive fiber coupler array, a plurality of first phase modulators, a plurality of second QWPs, a plurality of second PBSs, a plurality of second PBCs, a first photodetector, a second photodetector, a first amplifier, a second amplifier, a first subtractor and a first piston phase error control module; The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the first phase modulator through the coupling fiber; The first phase modulator corresponds to the second QWP one by one, receives the diversity signal light, performs piston phase error compensation on the diversity signal light to obtain a first co-phase circularly polarized light, and sends the first co-phase circularly polarized light to the second QWP; The second QWP receives the first co-phase circularly polarized light to obtain a second linearly polarized light, and sends the second linearly polarized light to the second PBS; The second PBS receives the second linearly polarized light to obtain mutually orthogonal first polarization state light, and sends the first polarization state light to the second PBC; The second PBC performs coherent synthesis on the light of the same first polarization state to obtain two first synthesized light beams, sends any one of the first synthesized light beams to the first photodetector, and sends the other first synthesized light beam to the second photodetector; The first photodetector receives the arbitrary first synthetic light beam, detects the beam intensity of the arbitrary first synthetic light beam, and sends the arbitrary first synthetic light beam to the first amplifier; The second photodetector receives the other first synthetic light beam, detects the beam intensity of the other first synthetic light beam, and sends the other first synthetic light beam to the second amplifier; The first amplifier amplifies the signal of any one of the first synthetic light beams to obtain a first amplified signal, and sends the first amplified signal to the first subtractor; The second amplifier amplifies the signal of the other first synthetic light beam to obtain a second amplified signal, and sends the second amplified signal to the first subtractor; The first subtractor receives the first amplified signal and the second amplified signal to obtain a first differential signal, and demodulates the first amplified signal and the second amplified signal according to the first differential signal to obtain a first demodulated multi-aperture coherent synthesis laser; The first piston phase error control module is arranged between the first subtractor and the first phase modulator, and adjusts the piston phase error of the first phase modulator between different diversity signal lights according to the first amplified signal and the second amplified signal in the first subtractor; The method comprises: The FSOC transmitter generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver; The multi-aperture spatial diversity receiver receives the emission light, performs adaptive coupling on the emission light and performs coherent synthesis on the emission light to obtain multi-aperture coherent synthesis laser light, and demodulates and outputs the multi-aperture coherent synthesis laser light.

2. According to claim 1, the multi-aperture coherent synthesis laser communication method based on circular offset keying modulation is characterized in that: The multi-aperture spatial diversity receiver comprises: an adaptive fiber coupler array, a plurality of third QWPs, a plurality of second phase modulators, a plurality of third PBSs, a plurality of third PBCs, a third photodetector, a fourth photodetector, a third amplifier, a fourth amplifier, and a second subtractor; The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the third QWP through the coupling fiber; The third QWP receives the diversity signal light to obtain a third linearly polarized light, and sends the third linearly polarized light to the third PBS; The third PBS receives the third linearly polarized light to obtain mutually orthogonal second polarization state light, and sends the second polarization state light to the second phase modulator; The second phase modulator receives the second polarization state light, performs piston phase error compensation on the second polarization state light to obtain second co-phase circularly polarized light, and sends the second co-phase circularly polarized light to the third PBC; The third PBC performs coherent synthesis on the same second co-phase circularly polarized light to obtain two second synthesized light beams, sends any one of the second synthesized light beams to the third photodetector, and sends the other second synthesized light beam to the fourth photodetector; The third photodetector receives the arbitrary second composite light beam, detects the beam intensity of the arbitrary second composite light beam, and sends the arbitrary second composite light beam to the third amplifier; The fourth photodetector receives the other second composite light beam, detects the beam intensity of the other second composite light beam, and sends the other second composite light beam to the fourth amplifier; The third amplifier amplifies the signal of any one of the second synthetic light beams to obtain a third amplified signal, and sends the third amplified signal to the second subtractor; The fourth amplifier amplifies the signal of the other second synthetic light beam to obtain a fourth amplified signal, and sends the fourth amplified signal to the second subtractor; The second subtractor receives the third amplified signal and the fourth amplified signal to obtain a second differential signal, and demodulates the third amplified signal and the fourth amplified signal according to the second differential signal to obtain a second demodulated multi-aperture coherent synthesis laser.

3. The multi-aperture coherent synthesis laser communication method based on circular offset keying modulation according to claim 2 is characterized in that: The multi-aperture spatial diversity receiver further includes: a plurality of third phase modulators; The third phase modulator is arranged between the third PBCs and on the propagation path of the third synthetic light beam, and performs piston phase error compensation on the third synthetic light beam.

4. The multi-aperture coherent synthesis laser communication method based on circular offset keying modulation according to claim 3 is characterized in that: Also includes: Several fourth QWPs; The fourth QWP is disposed between the third PBC and the third photodetector and the fourth photodetector, receives the second synthetic light beam to obtain a fourth linearly polarized light, and sends the fourth linearly polarized light to the third photodetector and the fourth photodetector.

5. The multi-aperture coherent synthesis laser communication method based on circular shift keying modulation according to claim 2, characterized in that: Also includes: a fourth photodetector, a tilt aberration control module and a high voltage amplifier; The aperture division is performed on the emission light to obtain diversity signal light, and then the method further comprises: The fourth photodetector receives the diversity signal light, detects the beam intensity of the diversity signal light, and sends the diversity signal light to the tilt aberration control module; The tilt aberration control module receives the diversity signal light, generates a random control voltage according to the diversity signal light, sends the random control voltage to the high-voltage amplifier to obtain an amplified voltage, and sends the amplified voltage to the adaptive fiber coupler array to ensure that the fiber coupling efficiency of the diversity signal light reaches the maximum power.

6. The multi-aperture coherent synthesis laser communication method based on circular shift keying modulation according to claim 2, characterized in that: Also includes: a second piston phase error control module and a third piston phase error control module; The second piston phase error control module is arranged between the third amplifier and the second phase modulator, and adjusts the second piston phase error of the second phase modulator to different second co-phase circularly polarized lights according to the third amplified signal in the third amplifier; The third piston phase error control module is arranged between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error of the second phase modulator to different second co-phase circularly polarized lights according to the fourth amplified signal in the fourth amplifier.

7. The multi-aperture coherent synthesis laser communication method based on circular offset keying modulation according to claim 3, characterized in that: Also includes: a fourth piston phase error control module and a fifth piston phase error control module; The fourth piston phase error control module is arranged between the third amplifier and the third phase modulator, and adjusts the third piston phase error between different third synthetic light beams of the third phase modulator according to the third amplified signal in the third amplifier; The fifth piston phase error control module is disposed between the fourth amplifier and the second phase modulator, and adjusts the second piston phase error of the third phase modulator between different third synthetic light beams according to the fourth amplified signal in the fourth amplifier.

8. A multi-aperture coherent synthesis laser communication system based on circular deflection keying modulation, characterized in that: include: FSOC transmitter and multi-aperture spatial diversity receiver; wherein the FSOC transmitter comprises: a laser transmitter, a first PBS, a first PBC, a first QWP, a fiber amplifier and a collimator; The laser transmitter emits FSOC signal light, and the FSOC signal light passes through the first PBS to obtain two mutually orthogonal first polarized lights; Phase modulate any one beam of first polarized light to obtain modulated polarized light, and send the modulated polarized light and another beam of first polarized light to the first PBC; The first PBC receives the modulated polarized light and another first polarized light to obtain a first linear polarized light, and sends the first linear polarized light to the first QWP; The first QWP receives the first linearly polarized light to obtain a first circularly polarized light, and sends the first circularly polarized light to the optical fiber amplifier; The optical fiber amplifier amplifies the first circularly polarized light to obtain processed circularly polarized light, and sends the processed circularly polarized light to the collimator to obtain emitted light; The multi-aperture spatial diversity receiver comprises: an adaptive fiber coupler array, a plurality of first phase modulators, a plurality of second QWPs, a plurality of second PBSs, a plurality of second PBCs, a first photodetector, a second photodetector, a first amplifier, a second amplifier, a first subtractor and a first piston phase error control module; The adaptive fiber coupler array receives the emission light, performs aperture division on the emission light to obtain diversity signal light, couples the diversity signal light to a coupling fiber, and sends the diversity signal light to the first phase modulator through the coupling fiber; The first phase modulator corresponds to the second QWP one by one, receives the diversity signal light, performs piston phase error compensation on the diversity signal light to obtain a first co-phase circularly polarized light, and sends the first co-phase circularly polarized light to the second QWP; The second QWP receives the first co-phase circularly polarized light to obtain a second linearly polarized light, and sends the second linearly polarized light to the second PBS; The second PBS receives the second linearly polarized light to obtain mutually orthogonal first polarization state light, and sends the first polarization state light to the second PBC; The second PBC performs coherent synthesis on the light of the same first polarization state to obtain two first synthesized light beams, sends any one of the first synthesized light beams to the first photodetector, and sends the other first synthesized light beam to the second photodetector; The first photodetector receives the arbitrary first synthetic light beam, detects the beam intensity of the arbitrary first synthetic light beam, and sends the arbitrary first synthetic light beam to the first amplifier; The second photodetector receives the other first synthetic light beam, detects the beam intensity of the other first synthetic light beam, and sends the other first synthetic light beam to the second amplifier; The first amplifier amplifies the signal of any one of the first synthetic light beams to obtain a first amplified signal, and sends the first amplified signal to the first subtractor; The second amplifier amplifies the signal of the other first synthetic light beam to obtain a second amplified signal, and sends the second amplified signal to the first subtractor; The first subtractor receives the first amplified signal and the second amplified signal to obtain a first differential signal, and demodulates the first amplified signal and the second amplified signal according to the first differential signal to obtain a first demodulated multi-aperture coherent synthesis laser; The first piston phase error control module is arranged between the first subtractor and the first phase modulator, and adjusts the piston phase error of the first phase modulator between different diversity signal lights according to the first amplified signal and the second amplified signal in the first subtractor; The FSOC transmitter generates FSOC signal light, performs CPolSK modulation on the FSOC signal light to obtain transmission light, and sends the transmission light to the multi-aperture spatial diversity receiver; The multi-aperture spatial diversity receiver receives the emission light, performs adaptive coupling on the emission light and performs coherent synthesis on the emission light to obtain multi-aperture coherent synthesis laser light, and demodulates and outputs the multi-aperture coherent synthesis laser light.

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