Space laser communication device and communication method

Abstract

The invention relates to a space laser communication device and a communication method. The device comprises a laser communication transmitting end device, a laser communication relay end device and a laser communication receiving end device which are arranged along a light path, after carrier laser generated by the laser communication transmitting end device enters the relay end device, the carrier laser and laser generated by the relay end device are subjected to time sequence coherent combination to obtain new carrier laser, and the new carrier laser is transmitted to the laser communication receiving end device. And the laser communication receiving end device receives the new carrier laser and decodes the new carrier laser, so that space laser communication is completed. The multi-dimensional laser carrier, the secondary coding technology and the like are utilized, the information dimension of laser communication is greatly improved, the bit error rate is reduced, and the confidentiality and safety of an existing laser space communication system are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of laser and communication technology, specifically to a space laser communication device and communication method. Background Technology

[0002] Laser space communication technology refers to an advanced communication technology that uses lasers as an information carrier to transmit information at high speed between space platforms (such as satellites, spacecraft, deep space probes, and near-space vehicles) or between space and the ground. Its core advantages lie in its ultra-large communication capacity, extremely low power consumption, strong resistance to electromagnetic interference, and high security, making it considered one of the core supporting technologies for future space information networks.

[0003] With the development of the information age, the amount of information transmitted is growing exponentially. Traditional microwave communication systems can no longer meet user needs, while space laser communication systems have attracted widespread attention due to their advantages such as higher capacity, greater bandwidth, and faster communication speeds. Space laser communication technology combines the advantages of fiber optic communication and microwave communication. It does not require the laying of optical fibers, avoiding the problem of spectrum limitations. At the same time, this technology does not require approval and can be used directly, which has significant advantages.

[0004] Under current space laser communication technology, when a laser beam traverses the atmosphere, it may experience weak "leakage" due to atmospheric scattering (such as Rayleigh scattering and Mie scattering) or reflection from space objects. Attackers can reconstruct parts of the communication content by deploying distributed receiving arrays on the ground, leading to security issues such as laser communication information leakage. Therefore, improving the confidentiality and security of space laser communication has become an urgent problem to be solved. Summary of the Invention

[0005] The main objective of this invention is to solve the aforementioned problems existing in the prior art and to provide a space laser communication device, which includes: A laser communication transmitter device is used to output a carrier laser carrying encrypted information and allow it to pass through the atmosphere and enter the laser communication relay device. A laser communication relay device is used to output a specific laser and perform time-series coherent synthesis with the carrier laser to achieve secondary encryption. The resulting new carrier laser passes through the atmosphere and enters the laser communication receiving device. A laser communication receiver device is used to receive new carrier laser light and decode it to obtain the transmitted information.

[0006] In the above scheme, the laser communication transmitter device includes a signal source control component and a fiber laser (1), an electro-optic modulator (2), a wavelength division multiplexer (3), a splitting processing component, and a fiber combiner (8) arranged along the carrier laser optical path. The signal source control component is directly or indirectly connected to and controls the fiber laser (1), the electro-optic modulator (2), the wavelength division multiplexer (3), and the splitting processing component. The fiber laser (1) is controlled to generate N (N≥2) lasers of different wavelengths (i.e., multi-wavelength lasers). These lasers are split into N beams according to wavelength (i.e., one laser beam per wavelength) after passing through the electro-optic modulator (2). After the laser beams of different wavelengths are processed by the splitting processing component (i.e., first encryption), they enter the fiber combiner (8) for beam combining to obtain a carrier laser carrying encrypted information.

[0007] In the above scheme, the splitting processing component includes N splits, and each split includes an optical fiber delayer and an ultra-narrowband optical fiber filter arranged along the carrier laser optical path.

[0008] In the above scheme, the signal source control component includes a signal source (24), an encoder (9), and a transmitter controller (10) connected in sequence. The transmitter controller (10) is connected to and controls the fiber laser (1), the electro-optic modulator (2), each fiber delay unit in the splitting processing component, and the laser communication relay device (specifically the receiver controller 19).

[0009] In the above scheme, the laser communication relay device includes a laser (17), a laser control component, and a polarization control module (11), a folding mirror (13), and a dichroic mirror (14) arranged along the carrier laser optical path. The laser control component is directly or indirectly connected to the laser (17) and the polarization control module (11) and controls them; after the carrier laser passes through the polarization control module (11), it illuminates the folding mirror (13), and the folding mirror (13) reflects the carrier laser onto the dichroic mirror (14). The N different wavelength lasers (i.e., multi-wavelength lasers) generated by the laser (17) illuminate the dichroic mirror (14) and are time-coherently synthesized with the carrier laser to complete the secondary encryption. The new carrier laser obtained thereby passes through the atmosphere and enters the laser communication receiving device.

[0010] In the above scheme, when the N different wavelength lasers (i.e., multi-wavelength lasers) generated by the laser (17) reach the dichroic mirror (14), they completely cancel each other out, partially cancel each other out, or are completely incoherent with the carrier laser. When the two completely cancel each other out, the laser generated by the laser (17) and the carrier laser have the same center wavelength, linewidth, and modulation frequency in real time. At this time, the two laser beams have the same intensity and a constant phase difference, so they can cancel each other out.

[0011] In the above scheme, the laser control assembly includes an electrically controlled polarization state control module (12), a phase control module (15), a delay unit (16), an absorption cell (18), a receiver controller (19), and a laser detection module (20). The laser (17), delay unit (16), phase control module (15), electrically controlled polarization state control module (12), dichroic mirror (14), and absorption cell (18) are arranged along the optical path of the laser (17) (which is perpendicular to the optical path of the carrier laser). The receiver controller (19) is connected to and controls the laser (17), delay unit (16), phase control module (15), electrically controlled polarization state control module (12), laser detection module (20), and the transmitter controller (10) of the laser communication transmitter device. The laser detection module (20) is connected to the polarization control module (11).

[0012] In the above scheme, the folding mirror (13) and the dichroic mirror (14) are both arranged at an angle (they can be perpendicular or not perpendicular to each other). The surface of the dichroic mirror (14) is coated with a film layer with a specific (50%) laser reflectivity, which can combine the carrier laser and the two laser beams emitted by the laser (17) into one beam to obtain a new carrier laser.

[0013] In the above scheme, the laser beam wavelengths generated by the laser communication transmitter device (i.e., fiber laser 1) and the laser communication relay device (i.e., laser 17) are both in the range of 1000-1600nm.

[0014] In the above scheme, the laser communication receiving device includes a detector (21), a decoder (22), and a computer (23) arranged along the new carrier laser optical path.

[0015] The second objective of this invention is to provide a method for space laser communication using the above-mentioned device, comprising: an encoder (9) encoding information output by a signal source (24) and loading it onto a transmitter controller (10); the transmitter controller (10) controlling a fiber laser (1) to generate multi-wavelength lasers; the lasers are split by a wavelength division multiplexer (3) and then enter different paths for encryption processing; and are then processed by a fiber combiner (8) into carrier lasers carrying encrypted information; the carrier lasers are transmitted through the atmosphere and enter a laser communication relay device, where they are coherently combined with the multi-wavelength lasers generated by a laser (17) at a dichroic mirror (14); the output state of the laser (17) is controlled to perform secondary encryption on the carrier lasers to obtain new carrier lasers; the new carrier lasers are transmitted through the atmosphere again and enter a laser communication receiver device for decoding to obtain the transmitted information.

[0016] Compared with existing similar products or technologies, the advantages of this invention are mainly reflected in the following points: (1) Using fiber laser as a laser source, a multi-wavelength, intensity-variable sequence of pulsed lasers is generated by an electro-optic modulator. When the laser enters the relay device, it is coherently synthesized with a similar laser emitted by the laser inside the relay device, thereby realizing secondary encoding and encryption of the signal carrier and greatly improving the confidentiality and security of laser communication; (2) The device utilizes multi-dimensional laser carriers and secondary encoding technologies, which not only improves the information dimension of laser communication and reduces the bit error rate, but also effectively improves the confidentiality performance of existing laser space communication systems, which is of great significance in the fields of national defense, aerospace, and information security; (3) The overall structure of the device is relatively simple, with a high level of informatization and intelligence, and has good application potential in various fields. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the space laser communication device described in this invention.

[0018] Figure 2 This is a timing diagram of the continuous laser output from a fiber laser.

[0019] Figure 3 This is a timing diagram of the laser output from each branch after passing through the wavelength division multiplexer.

[0020] Figure 4 This is the timing diagram of the laser output after passing through the beam combiner.

[0021] Figure 5 This is a timing diagram of the laser beam and the laser beam emitted by the laser source after coherent encoding.

[0022] Reference numerals: 1-Fiber laser, 2-Electro-optic modulator, 3-Wavelength division multiplexer, 4-First fiber delayer, 5-First ultra-narrowband fiber filter, 6-Second fiber delayer, 7-Second ultra-narrowband fiber filter, 8-Fiber combiner, 9-Encoder, 10-Transmitter controller, 11-Polarization control module, 12-Electrically controlled polarization state control module, 13-Folding mirror, 14-Dichroic mirror, 15-Phase control module, 16-Delayer, 17-Laser, 18-Absorption cell, 19-Receiver controller, 20-Laser detection module, 21-Detector, 22-Decoder, 23-Computer, 24-Signal source. Detailed Implementation

[0023] To enable those skilled in the art to fully understand the objectives, technical solutions, and advantages of this invention, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be emphasized that the illustrative embodiments and descriptions of this invention are for explaining the invention only and do not constitute any limitation on the invention.

[0024] It should also be noted that, to avoid obscuring the invention with unnecessary details, only structures and / or processing steps closely related to the technical solution of the invention are shown in the accompanying drawings, while other details not closely related to the invention are omitted. This treatment does not affect those skilled in the art's understanding and implementation of the invention. The term "comprising / including" primarily refers to the presence of features, elements, steps, or components, and does not exclude the presence or addition of one or more other features, elements, steps, or components. Unless otherwise specified, the terms "connected," "linked," etc., can refer not only to a direct connection but also to an indirect connection or wireless connection with an intermediary. In the accompanying drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0025] like Figure 1 As shown, the space laser communication device provided by this invention mainly includes a laser communication transmitter, a laser communication relay, and a laser communication receiver. The laser communication transmitter outputs a carrier laser carrying encrypted information. After atmospheric transmission, the carrier laser enters the laser communication relay. Through time-series coherent synthesis with the built-in laser of the laser communication relay, secondary encryption of the carrier laser is achieved. The secondary encrypted carrier laser then enters the laser communication receiver for demodulation after atmospheric transmission, thereby realizing laser space communication.

[0026] The laser communication transmitter is mainly used to output a carrier laser carrying encrypted information. This carrier laser can encrypt information through multi-dimensional changes such as wavelength, intensity, and modulation frequency encoding. To achieve the above purpose, the laser communication transmitter mainly includes a fiber laser (1), an electro-optic modulator (2), a wavelength division multiplexer (3), a first fiber delay unit (4), a first ultra-narrowband fiber filter (5), a second fiber delay unit (6), a second ultra-narrowband fiber filter (7), a fiber combiner (8), an encoder (9), a transmitter controller (10), and a signal source (24). Among them, the fiber laser (1), electro-optic modulator (2), wavelength division multiplexer (3), and fiber combiner (8) are arranged sequentially along the optical path. The first fiber delay unit (4) and the first ultra-narrowband fiber filter (5) are arranged sequentially to form one branch, and the second fiber delay unit (6) and the second ultra-narrowband fiber filter (7) are arranged sequentially to form another branch. These two branches are arranged side by side on the optical path between the wavelength division multiplexer (3) and the fiber combiner (8). The signal source (24), encoder (9), transmitter controller (10), and fiber laser (1) are connected in sequence. The transmitter controller (10) is also connected to the electro-optic modulator (2), the first fiber delay unit (4), and the second fiber delay unit (6).

[0027] In some other embodiments, the number of similar splits can be three or more, mainly determined by the fiber laser (1) generating several continuous laser beams of different wavelengths. Each beam includes a fiber delayer and an ultra-narrowband fiber filter arranged in sequence. After the different wavelength laser beams split from the wavelength division multiplexer (3) enter their respective splitting processes, they are finally merged into the fiber combiner (8) to form a single carrier laser beam.

[0028] The functions of each module or component in the laser communication transmitter device are as follows: Fiber lasers (1) are mainly used to generate continuous lasers with at least two different wavelengths (such as 1064nm and 1550nm) and a linewidth of 2GHz. Figure 2 The timing diagram of the continuous laser output of the fiber laser (1) includes two laser beams with wavelengths of 1064nm and 1550nm.

[0029] The electro-optic modulator (2) is mainly used to receive the control signal sent by the transmitter controller (10) and to perform high-speed modulation on the laser emitted by the fiber laser (1) to generate a high-speed pulse signal in the GHz range.

[0030] The wavelength division multiplexer (3) is mainly used to separate lasers of different wavelengths (such as 1064nm and 1550nm) generated by the fiber laser (1) so that they enter different paths for encryption processing. Figure 3 The laser timing diagram is shown for each output after passing through the wavelength division multiplexer (3).

[0031] The first fiber delay unit (4) and the second fiber delay unit (6) are mainly used to receive the control signal sent by the transmitter controller (10) and to delay the pulse laser of each branch corresponding wavelength (such as 1064nm, 1550nm).

[0032] The first ultra-narrowband fiber filter (5) and the second ultra-narrowband fiber filter (7) are mainly used to filter and compress the pulse laser spectrum width of the corresponding wavelengths (such as 1064nm and 1550nm) of each branch, with a compression width of 1GHz.

[0033] The fiber combiner (8) is mainly used to combine lasers of different wavelengths (such as 1064nm and 1550nm) to form a processed carrier laser. Figure 4 The output laser timing diagram is shown after passing through the beam combiner (8).

[0034] The encoder (9) is mainly used to receive signals from the signal source (24) and encode them according to the information content.

[0035] The transmitter controller (10) is mainly used to receive the encoded signal emitted by the encoder (9) and generate the corresponding control signal. The control signal directly or indirectly acts on the fiber laser (1), electro-optic modulator (2), wavelength division multiplexer (3), first fiber delay (4) and second fiber delay (6) to generate the laser carrier signal required by the signal source (24).

[0036] The signal source (24) is mainly used to generate corresponding signals based on communication information.

[0037] The laser communication relay device mainly includes a polarization control module (11), an electrically controlled polarization state control module (12), a folding mirror (13), a dichroic mirror (14), a phase control module (15), a delay unit (16), a laser (17), an absorption cell (18), a receiver controller (19), and a laser detection module (20). The polarization control module (11) faces the incident direction of the carrier laser and is arranged sequentially along the optical path with the folding mirror (13) and the dichroic mirror (14). Both the folding mirror (13) and the dichroic mirror (14) are tilted at 45° and perpendicular to each other. The electrically controlled polarization state control module (12), the phase control module (15), the delay unit (16), and the laser (17) are arranged sequentially on the left side of the dichroic mirror (14) against the optical path. The absorption cell (18) is arranged on the right side of the dichroic mirror (14). The receiver controller (19) is connected to the laser (17), the phase control module (15), the delay unit (16), the electronically controlled polarization state control module (12), the laser detection module (20), and the transmitter controller (10) of the laser communication transmitter device. The laser detection module (20) is also connected to the polarization control module (11).

[0038] The carrier laser from the fiber combiner (8) passes through the atmosphere and enters the polarization control module (11). After passing through the polarization control module (11), it is reflected by the folding mirror (13) onto the dichroic mirror (14). The carrier laser and the laser beam emitted by the laser (17) are then coherently combined in a time sequence and then enter the atmosphere through the transmission dichroic mirror (14). Figure 5 The timing diagram of the laser emitted by the carrier laser and the laser (17) after coherent coding is shown. As a complement, excess laser light is reflected or transmitted to the absorption cell (18) by the dichroic mirror (14) for absorption.

[0039] The functions of each module or component in the laser communication relay device are as follows: The polarization control module (11) is mainly used to control the polarization of the carrier laser emitted by the laser communication transmitter, making it polarized light. The laser beam with a wavelength of 1064nm has a polarization direction of W1 and a phase of ø1; the laser beam with a wavelength of 1550nm has a polarization direction of W2 and a phase of ø2. In addition, the carrier signal generated inside the polarization control module (11) can be captured by the laser detection module (20) and then transmitted to the receiver controller (19).

[0040] The electronically controlled polarization state control module (12) is mainly used to control the polarization state direction of the laser output by the laser (17). The polarization direction of the laser beam with a wavelength of 1064nm is W1 and the phase is ø3; the polarization direction of the laser beam with a wavelength of 1550nm is W2 and the phase is ø4.

[0041] The folding mirror (13) is mainly used to deflect the light path of the carrier laser emitted by the laser communication transmitter device, so that it is oriented and refracted onto the dichroic mirror (14).

[0042] The surface of the dichroic mirror (14) is coated with a film layer with 50% laser reflectivity, which can combine the carrier laser emitted by the laser communication transmitter device and the laser emitted by the laser (17) into one.

[0043] The phase control module (15) is mainly used to control the phase of the laser processed by the delay unit (16), so that the phase of the 1064nm laser emitted by the laser (17) is ø3 and the phase of the 1550nm laser is ø4, which is convenient to cancel out the carrier laser during subsequent synthesis.

[0044] The delay unit (16) is mainly used to delay the laser emitted by the laser (17).

[0045] The laser (17) is mainly used to generate two (or multiple, same as the laser beam generated by the fiber laser) continuous lasers with wavelengths of 1064nm and 1550nm respectively, with a linewidth of 1GHz and a modulation frequency the same as that of the carrier laser.

[0046] The absorption cell (18) is mainly used to absorb the remaining laser light that has not been utilized.

[0047] The receiver controller (19) is mainly used to receive control signals from the laser detection module (20) and the transmitter controller (10) and generate corresponding multi-channel control signals, thereby directly or indirectly controlling the electronic polarization state control module 12, the phase control module (15), the delay unit (16), the laser (17), etc.

[0048] The laser detection module (20) is mainly used to receive the carrier signal inside the polarization control module (11), and to calculate and identify the multi-dimensional information such as the modulation frequency, phase (ø1 and ø2), and polarization (W1 and W2) of the carrier laser originating from the laser communication transmitter device in the carrier signal, and then transmit the corresponding signal to the receiver controller (19).

[0049] The laser communication receiver device includes a detector (21), a decoder (22), and a computer (23) arranged along the optical path. The carrier laser refracted or transmitted from the dichroic mirror (14) of the laser communication relay device passes through the atmosphere and then sequentially through the detector (21), decoder (22), and computer (23). The processed information is displayed and stored on the computer.

[0050] The detector (21) is mainly used to receive laser modulation signals and generate electrical signals to transmit to the decoder (22). The decoder (22) is mainly used to receive the signals transmitted from the detector (21) and decode the carrier wave. The computer (23) is used to receive the signals processed by the decoder (22) and obtain the transmission information.

[0051] The working principle of the space laser communication device provided by the present invention is as follows: The encoder (9) encodes the information content generated by the signal source (24) and loads the corresponding signal onto the transmitter controller (10). The transmitter controller (10) controls the fiber laser (1) to generate two continuous laser beams of 1064nm and 1550nm (or multiple continuous laser beams of other wavelengths) according to the corresponding control signal. These two laser beams are split into two paths after passing through the wavelength division multiplexer (3). At the same time, the electro-optic modulator (2), the first fiber delayer (4), and the second fiber delayer (6) receive the control signal sent by the transmitter controller (10) and perform delay and other processing on the two pulse carrier lasers of different wavelengths (1064nm and 1550nm) of the split path. Multi-dimensional encryption is performed by combining noise signal data and information signal data. The two pulse carrier laser beams are then combined into one carrier laser beam by the fiber combiner (8).

[0052] After being transmitted through the atmosphere, the carrier laser enters the polarization control module (11) in the laser communication relay device. The module controls the polarization of the carrier laser, converting both the 1064nm and 1550nm lasers into polarized light with polarization directions W1 and W2, and phases ø1 and ø2, respectively. The carrier laser is then directionally reflected by the folding mirror (13) onto the dichroic mirror (14). Simultaneously, the optical signal received by the polarization control module (11) is captured by the laser detection module (20), which calculates and identifies multi-dimensional information such as wavelength, modulation frequency, phase, and polarization in the optical signal, generating corresponding signals that are transmitted to the receiver controller (19). The receiver controller (19) then generates control signals to control the laser (17), delay unit (16), and phase control module (15) in the laser communication relay device.

[0053] The laser (17) generates two laser beams with the same intensity and modulation frequency as the laser communication transmitter, and wavelengths of 1064nm and 1550nm respectively. Under the control of the receiver controller 19, the two laser beams emitted by the laser (17) are respectively sent to the dichroic mirror (14) via the delay unit (16), the phase control module (15), and the electrically controlled polarization state control module (12). At the dichroic mirror (14), the two laser beams with wavelengths of 1064nm and 1550nm originating from the laser (17) have phases of ø3 and ø4, and polarization directions of W1 and W2 respectively. The two laser beams with wavelengths of 1064nm and 1550nm originating from the fiber laser (1) have phases of ø1 and ø2, and polarization directions of W1 and W2 respectively. Where ø1-ø3=ø2-ø4=(2k+1)π (k is an integer), thus achieving the coherent cancellation condition. At this time, the laser emitted by laser (17) cancels out the carrier laser emitted by fiber laser (1), and the signal is 0. If the receiver controller 19 is turned off to stop the laser (17) from emitting light, or if the phase difference between the two laser beams is not constant at (2k+1)π, then the two laser beams are incoherent, and the signal is 1. Through continuous control in this way, secondary encoding encryption of the carrier laser in the laser communication relay device can be realized, thereby greatly improving the security performance of laser space communication.

[0054] The new carrier laser from the laser communication relay device re-enters the atmosphere and is transmitted to the laser communication receiver device. After the detector (21) in the laser communication receiver device receives the carrier signal, it calculates the communication content through the decoder (22) and uploads it to the computer (23) to complete the laser communication.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can have many other embodiments. Any modifications, equivalent substitutions, or improvements made without departing from the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A space laser communication device, characterized in that... The device includes: a laser communication transmitter for outputting a carrier laser carrying encrypted information and transmitting it through the atmosphere to a laser communication relay device; a laser communication relay device for outputting a specific laser and performing time-sequential coherent synthesis with the carrier laser, thereby obtaining a new carrier laser that passes through the atmosphere and enters a laser communication receiver device; and a laser communication receiver for receiving the new carrier laser and decoding it to obtain the transmitted information.

2. The space laser communication device as described in claim 1, characterized in that: The laser communication transmitter device includes a signal source control component and a fiber laser, an electro-optic modulator, a wavelength division multiplexer, a splitting processing component, and a fiber combiner arranged along the carrier laser optical path. The signal source control component is connected to the fiber laser, the electro-optic modulator, the wavelength division multiplexer, and the splitting processing component. The fiber laser is controlled to generate N lasers of different wavelengths. After passing through the electro-optic modulator, the lasers enter the wavelength division multiplexer and are split into N beams according to their wavelengths. After being processed by the splitting processing component, the laser beams of different wavelengths enter the fiber combiner for beam combining to obtain a carrier laser carrying encrypted information, where N≥2.

3. The space laser communication device as described in claim 2, characterized in that: The branching processing component includes N branches, each of which includes an optical fiber delayer and an ultra-narrowband optical fiber filter arranged along the carrier laser optical path.

4. The space laser communication device as described in claim 3, characterized in that: The signal source control component includes a signal source, an encoder, and a transmitter controller connected in sequence. The transmitter controller is connected to the fiber laser, the electro-optic modulator, each fiber delay unit in the splitting processing component, and the laser communication relay device.

5. The space laser communication device as described in claim 1, characterized in that: The laser communication relay device includes a laser, a laser control component, and a polarization control module, a folding mirror, and a dichroic mirror arranged along the carrier laser optical path. The laser control component is connected to the laser and the polarization control module. After the carrier laser passes through the polarization control module, it illuminates the folding mirror. The folding mirror reflects the carrier laser onto the dichroic mirror. N lasers of different wavelengths generated by the laser illuminate the dichroic mirror and are coherently combined with the carrier laser in a time sequence. The resulting new carrier laser passes through the atmosphere and enters the laser communication receiving device.

6. The space laser communication device as described in claim 5, characterized in that: When N lasers of different wavelengths generated by a laser reach a dichroic mirror, they completely cancel each other out, partially cancel each other out, or are completely incoherent with the carrier laser, thereby achieving temporal coherent synthesis or non-temporal coherent synthesis.

7. The space laser communication device as described in claim 5, characterized in that: The laser control assembly includes an electrically controlled polarization state control module, a phase control module, a delay unit, an absorption cell, a receiver controller, and a laser detection module. The laser, delay unit, phase control module, electrically controlled polarization state control module, dichroic mirror, and absorption cell are arranged along the optical path of the laser. The receiver controller is connected to the laser, phase control module, delay unit, electrically controlled polarization state control module, laser detection module, and laser communication transmitter device. The laser detection module is connected to the polarization control module.

8. The space laser communication device as described in claim 5, characterized in that: The folding mirror and the dichroic mirror are both arranged at an angle. The carrier laser and the laser emitted by the laser are combined at the dichroic mirror to obtain a new carrier laser.

9. The space laser communication device as described in claim 1, characterized in that: The laser communication receiving device includes a detector, a decoder, and a computer arranged along the new carrier laser optical path.

10. A method for space laser communication, characterized in that... The method includes: an encoder encoding information output from a signal source and loading it onto a transmitter controller; the transmitter controller controlling a fiber laser to generate multi-wavelength laser light; the laser light being split by a wavelength division multiplexer and then entering different paths for encryption processing; and then processed by a fiber combiner into a carrier laser carrying encrypted information; the carrier laser light being transmitted through the atmosphere and entering a laser communication relay device; at a dichroic mirror, it being coherently combined with the multi-wavelength laser light generated by the laser; the laser light output state being controlled to perform secondary encryption on the carrier laser light to obtain a new carrier laser light; the new carrier laser light being transmitted through the atmosphere again and entering a laser communication receiver device for decoding to obtain the transmitted information.

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