Multi-aperture coherent synthetic optical phased array laser communication device and method

Abstract

The application discloses a multi-aperture coherent synthesis optical phased array laser communication device and method, belongs to the technical field of laser communication, and solves the technical problem that in the prior art, due to the fact that a single phase compensator is relied on to perform centralized phase regulation on all input light beams, and when long-distance transmission is performed, the wavefront distortion is caused by the influence of atmospheric turbulence, it is difficult to accurately match the phase difference of each light beam in real time, and the far-field coherence of a synthesized light beam is significantly reduced. The laser communication device is constructed, a multi-aperture coherent light synthesis unit cascade architecture is adopted, a signal transceiving logic is reconstructed by using a multi-beam interference and a synthesis aperture principle, the light path coupling of the multi-aperture is completed, the phase of each coherent light synthesis unit is accurately regulated, and high-quality communication is realized. The application is used for realizing dynamic tracking and compensation of rapid random phase fluctuations caused by turbulence, and efficient and accurate coherent aperture synthesis.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser communication, in particular to a multi-aperture coherent synthesis optical phased array laser communication device and method. BACKGROUND

[0002] Free-Space Optical Communication, FSO, as a new generation of high-speed information transmission technology, realizes data interaction by means of spatial transmission of laser beams, and not only shows unique advantages in satellite communication, deep space exploration and near-earth high-speed link, but also has outstanding characteristics such as anti-electromagnetic interference and low power consumption. However, its actual application is deeply affected by multiple problems, such as wavefront distortion caused by atmospheric turbulence, beam jitter caused by platform vibration, and link attenuation in long-distance transmission. These factors jointly affect the reliability and transmission quality of the system. Therefore, how to ensure the reliability and transmission quality of the system is a key problem faced by the field of laser communication.

[0003] Traditional solutions such as mechanical tracking mirrors and single-aperture receiving technology have slow response speed and limited aperture gain, and are difficult to meet the needs of high-dynamic and long-distance communication scenarios. To break through the above limitations, coherent aperture synthesis technology emerges as the times require. This technology accurately superimposes the beams of multiple independent light sources through multi-beam interference and synthetic aperture principles to form a synthetic beam with an equivalent large aperture. Compared with traditional single-aperture signal systems, multi-aperture technology corrects atmospheric distortion through multi-beam synthesis wavefront to improve the anti-turbulence ability, significantly enhances the signal transmitting and receiving gain and the recovery ability to deal with channel and platform interference, thereby realizing high-quality communication, solving the dilemma of traditional aperture receiving, and having great application potential. However, in actual application, the requirement of phase consistency needs to be met, and too many apertures may lead to a decrease in signal coherence or a sharp increase in computational complexity. Traditional coherent synthesis technology usually uses a beam combiner and relies on a single phase compensator to centrally control the phase of all input beams. However, due to the different influences of temperature and stress and other environmental disturbances on each beam during transmission, and the random and dynamic wavefront distortion introduced by atmospheric turbulence during long-distance transmission, the traditional method is difficult to accurately match the phase difference of each beam in real time, resulting in a significant decrease in the far-field coherence of the synthetic beam.

[0004] In the prior art, Chinese patent document CN115567115A discloses "an optical phased array laser communication system based on multiple aperture coherent synthesis", including a large deflection angle optical phased array antenna, a relay optical path, a fiber phase shifter, a fiber combiner, a fiber beam splitter, a laser emitting unit, a coherent demodulation unit, an optical power detection unit, a phase control unit, the large deflection angle optical phased array antenna realizes the deflection of the light beam in a large angle range, the relay optical path realizes the tracking of the light beam and couples to the optical fiber, the fiber phase shifter and the fiber combiner coherently synthesize the light coupled to the optical fiber via multiple aperture optical phased array antennas to enhance the optical power of the received signal. However, this technical solution adopts an N*1 single-mode fiber combiner, relies on a single phase compensator to perform centralized phase regulation on all input light beams, and can cause the problem of significant decline of the far-field coherence of the synthesized light beam due to the difficulty in real-time accurate matching of the phase difference of each light beam.

[0005] In summary, the prior art has the technical problem of significant decline of the far-field coherence of the synthesized light beam due to the difficulty in real-time accurate matching of the phase difference of each light beam due to the dependence on a single phase compensator for centralized phase regulation on all input light beams, and the wavefront distortion caused by the influence of atmospheric turbulence during long-distance transmission. SUMMARY

[0006] The present application solves the technical problem of significant decline of the far-field coherence of the synthesized light beam due to the difficulty in real-time accurate matching of the phase difference of each light beam due to the dependence on a single phase compensator for centralized phase regulation on all input light beams, and the wavefront distortion caused by the influence of atmospheric turbulence during long-distance transmission.

[0007] The laser signal transmitting device according to the present application comprises:

[0008] The first APT module drives the precision servo mechanism to perform wavefront correction using the first APT system when transmitting signals, and locks the target information at the center of the sensor field of view based on the first APT system;

[0009] The first coherent aperture synthesis module constructs a first coherent aperture synthesis system, including a host computer, a plurality of collimators and a plurality of coherent light synthesis units, cascades the plurality of coherent light synthesis units, and uses the cascaded coherent light synthesis units to perform optical coupling on the modulated coherent signal light;

[0010] The host computer outputs an analog voltage to the corresponding coherent light synthesis unit;

[0011] The plurality of collimators are used to output the coherent signal light after optical coupling;

[0012] The modulation module modulates the coherent signal light generated by the laser using a modulator when transmitting signals, and is used to carry transmission information.

[0013] The laser signal receiving device comprises:

[0014] The second APT module drives the precision servo mechanism to perform wavefront correction by using the second APT system when receiving the signal, and locks the target information at the center of the sensor field of view based on the second APT system;

[0015] The second coherent aperture synthesis module constructs a second coherent aperture synthesis system, which comprises a host computer, a photoelectric detector, a plurality of collimators and a plurality of coherent light synthesis units, cascades the plurality of coherent light synthesis units, and uses the cascaded coherent light synthesis units to perform optical path coupling on the incident light signal;

[0016] The host computer is used for receiving the voltage signal converted by the photoelectric detector and outputting a control voltage to the corresponding coherent light synthesis unit;

[0017] The photoelectric detector is used for converting the incident light signal after optical path coupling into a voltage signal;

[0018] The plurality of collimators are used for transmitting the incident light signal to the corresponding coherent light synthesis unit respectively;

[0019] The demodulation module demodulates the voltage signal converted by the photoelectric detector by using a demodulator to recover the original transmission information when receiving the signal.

[0020] The laser communication device comprises:

[0021] The APT module constructs an APT system and is used for executing the first APT module and the second APT module;

[0022] The coherent aperture synthesis module constructs a coherent aperture synthesis system and is used for executing the first coherent aperture synthesis module and the second coherent aperture synthesis module;

[0023] The coherent aperture synthesis system further comprises a circulator for isolating the transceiving signal;

[0024] The modulation and demodulation module constructs a modulation and demodulation system and is used for executing the modulation module and the demodulation module.

[0025] Further, in an embodiment of the present application, the coherent light synthesis unit comprises an input end , an input end , an output end , an output end , a fiber coupler and a phase shifter;

[0026] The input end The phase shifter is loaded to perform phase control, and the incident light signal passes through the input end and the input end into the fiber coupler for coupling, and the coupled incident light signal is output from the output end and the output end .

[0027] Further, in an embodiment of the present application, the phase shifter is loaded to perform phase control, specifically:

[0028] Ensure that the incident light signals of the input end and the input end are the same, and ensure that the phase difference between the input end and the input end is:

[0029] ;

[0030] wherein, is an integer.

[0031] Further, in an embodiment of the present application, the coupling ratio of the fiber coupler is 50 / 50.

[0032] Further, in an embodiment of the present application, when receiving signals, the device uses a compensation algorithm to compensate for the phase difference in real time according to the voltage signal.

[0033] Further, in an embodiment of the present application, the coherent aperture synthesis module further comprises a polarization controller and a polarization maintaining optical fiber, and the polarization controller and the polarization maintaining optical fiber are used to keep the signal light polarization state stable.

[0034] The laser communication method of the present application, the method is realized based on the above device, comprising the following steps:

[0035] Step 1, when transmitting and receiving signals, use the APT system to drive the precision servo mechanism to perform wavefront correction, and simultaneously lock the target information in the center of the sensor field of view based on the APT system;

[0036] Step 2, use the coherent aperture synthesis system to couple the optical path of the transmitting and receiving signals, and isolate the transmitting and receiving signals through the circulator;

[0037] Step 3, based on the modulation and demodulation system, modulate or demodulate the transmitting and receiving signals, specifically:

[0038] When transmitting signals, use the modulator to modulate the coherent signal light generated by the laser, and transmit the modulated coherent signal light to the cascaded coherent light synthesis unit for optical path coupling, and use multiple collimators to output the corresponding optical path coupled coherent signal light;

[0039] When receiving a signal, the incident light signal is transmitted to the cascaded coherent light synthesis unit by using multiple collimators for optical path coupling, the incident light signal after optical path coupling is converted into a voltage signal based on a photodetector, and the voltage signal converted by the photodetector is demodulated by using a demodulator, so that laser communication is realized.

[0040] The present application solves the technical problems in the prior art that due to the dependence on a single phase compensator for centralized phase regulation of all input light beams, and the influence of atmospheric turbulence on wavefront distortion during long-distance transmission, it is difficult to accurately match the phase difference of each light beam in real time, resulting in a significant decrease in the far-field coherence of the synthesized light beam. The specific beneficial effects include:

[0041] 1. The present application proposes a laser communication device adopting a coherent light synthesis unit with a cascaded architecture of sixteen apertures to reconstruct the signal transceiver logic based on the principles of multi-beam interference and synthetic aperture, and to effectively offset the link attenuation of long-distance transmission (such as interstellar and deep space exploration) by using multi-beam energy superposition. Compared with the traditional single-aperture system, the phase of the coherent light synthesis unit can be optimized in real time, effectively overcoming the technical problems of wavefront distortion and significant decrease in the far-field coherence of the synthesized light beam caused by target and platform motion, atmospheric turbulence and other disturbances, and the equivalent receiving area is increased by 16 times, and the transceiver gain is significantly improved.

[0042] 2. The present application proposes a laser communication device, which can realize efficient and accurate coherent aperture synthesis by fine regulation of the laser phase through multiple phase shifters, coupling and splitting of the light beam through multiple 3-dB couplers in cascade, and real-time optimization of the phase of the phase shifter by feedback of the optical power value of the photodetector. It has important significance for improving the performance of optical systems in complex environments.

[0043] 3. The present application proposes a laser communication device, which can simultaneously offset the triple interference of "target motion, platform vibration and atmospheric turbulence" by combining a precision servo mechanism of a turntable with an APT system error correction algorithm. In a strong wind environment near the ground, the attitude can still be adjusted in real time by the turntable, and the wavefront correction of APT is used to ensure uninterrupted link, and the SPGD algorithm is used to compensate the phase difference in real time with optical power as feedback to dynamically offset the wavefront distortion and polarization drift caused by atmospheric turbulence, so that the system can stably communicate under the influence of atmospheric turbulence. BRIEF DESCRIPTION OF DRAWINGS

[0044] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings, in which:

[0045] Figure 1 is the structure diagram of the laser communication device described in embodiment three;

[0046] Figure 2is a capture, aiming and tracking schematic diagram according to the third embodiment;

[0047] Figure 3 is a coherent light synthesis unit schematic diagram according to the fourth embodiment;

[0048] Figure 4 is a 16-aperture transmitting-receiving array schematic diagram based on coherent synthesis according to the fifth embodiment. DETAILED DESCRIPTION

[0049] Various embodiments of the present application will be described in detail below with reference to the drawings. The examples described by reference to the drawings are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0050] Embodiment one. The laser signal transmitting device according to the present embodiment, the device comprises:

[0051] The first APT module, when transmitting a signal, drives the precision servo mechanism to perform wavefront correction by using the first APT system, and locks the target information at the center of the sensor field of view based on the first APT system;

[0052] The first coherent aperture synthesis module, a first coherent aperture synthesis system is constructed, which comprises a host computer, a plurality of collimators and a plurality of coherent light synthesis units, the plurality of coherent light synthesis units are cascaded, and the coherent signal light after modulation is coupled by using the cascaded coherent light synthesis units;

[0053] The host computer outputs an analog voltage to the corresponding coherent light synthesis unit;

[0054] The plurality of collimators are used to output the coherent signal light after optical coupling;

[0055] The modulation module, when transmitting a signal, modulates the coherent signal light generated by the laser by using the modulator, which is used to carry transmission information.

[0056] In the prior art, when transmitting a laser signal at a long distance, atmospheric turbulence can seriously affect the imaging quality. Atmospheric turbulence can cause the phase of the laser beam to change randomly, thereby destroying the effect of coherent synthesis. Therefore, phase matching is a core challenge faced by multi-aperture coherent synthesis technology when transmitting a laser signal. In order to effectively synthesize the light beam, the phase of each light beam in the array must be matched and kept stable. Moreover, the existing laser signal transmitting device needs to be connected to a beam splitter and a power device, and then connected to a cascaded 3-db fiber coupler. When transmitting a signal, the light beam needs to be split, which can reduce the effective transmitting power of the transmitting end. The receiving end needs sufficient signal power to accurately detect information. The reduction of transmitting power can cause the signal-to-noise ratio of the receiving end to decrease, thereby affecting the signal receiving quality. Moreover, the transmitting and receiving communication integration cannot be realized. The existing technology usually connects multiple photodetectors in the transmitting device, which greatly increases the system complexity.

[0057] Therefore, in order to solve the above technical problems, the embodiment provides a laser signal transmitting device. The first APT system is used to first perform coarse tracking and quickly capture a target, thereby reducing the deviation. Then, the fine tracking is used to dynamically compensate for the deviation, so as to finally stably lock the target information at the center of the sensor field of view, thereby ensuring the continuous and accurate reception of the signal.

[0058] The modulator is used to modulate the coherent signal light generated by the laser. The modulated coherent signal light is transmitted to the cascaded coherent light synthesis unit for optical coupling. The multiple collimators are used to output the corresponding optical coupling coherent signal light. The host computer is built by taking the FPGA (programmable logic gate array) and the 32-bit ARM (microcontroller) as the hardware core. The host computer outputs an analog voltage to the corresponding coherent light synthesis unit, so as to control the phase of the coherent light synthesis unit. When transmitting a signal, multiple photodetectors do not need to be connected to feed back the voltage signal of the host computer, thereby reducing the complexity of phase control. The phase matching problem is effectively solved. Through the accurate modulation of the modulator on the coherent signal light and the cooperative control of the host computer, the phase of each light beam in the array can be accurately matched and kept stable. The effect of multi-aperture coherent synthesis is significantly improved. Moreover, the light beam does not need to be split, and the transmitting and receiving communication integration design can be realized.

[0059] Moreover, the light beam coupled by the coherent light synthesis unit and output by the collimator can reduce the influence of the random phase change caused by atmospheric turbulence, reduce the damage to the coherent synthesis effect, and further improve the imaging quality of long-distance laser signal transmission. The host computer is also used to uniformly manage the entire signal transmission and synthesis process. The optical coupling efficiency is optimized, the stability and reliability of the system operation are enhanced, and a powerful guarantee is provided for the efficient transmission of the laser signal.

[0060] Embodiment two. The laser signal receiving device provided in the embodiment comprises:

[0061] a second APT module, when receiving a signal, driving a precision servo mechanism to perform wavefront correction by using a second APT system, and locking target information at the center of a sensor field of view based on the second APT system;

[0062] a second coherent aperture synthesis module, constructing a second coherent aperture synthesis system, including a host computer, a photoelectric detector, a plurality of collimators, and a plurality of coherent light synthesis units, cascading the plurality of coherent light synthesis units, and coupling an incident light signal by using the cascaded coherent light synthesis units;

[0063] the host computer, configured to receive a voltage signal converted by the photoelectric detector, and output a control voltage to a corresponding coherent light synthesis unit;

[0064] the photoelectric detector, configured to convert the incident light signal coupled in an optical path into a voltage signal;

[0065] the plurality of collimators, configured to transmit the incident light signal to the corresponding coherent light synthesis unit respectively;

[0066] a demodulation module, configured to demodulate the voltage signal converted by the photoelectric detector by using a demodulator to recover original transmission information when receiving a signal.

[0067] In the prior art, when receiving a laser signal, the receiving end cannot actively control the phases of the light beams like the sending end, and must rely on signal processing after receiving to realize phase alignment. Atmospheric turbulence and transmission path differences can cause wavefront distortion, random changes in the phases of each channel, destruction of coherence, and time differences and phase differences of signals received by different apertures, resulting in a decrease in synthesis efficiency.

[0068] To solve the above technical problems, the embodiment provides a laser signal receiving device. When receiving a signal, the device transmits an incident light signal to cascaded coherent light synthesis units by using a plurality of collimators to couple the incident light signal in an optical path, converts the incident light signal coupled in the optical path into a voltage signal based on a photoelectric detector, transmits the converted voltage signal to a host computer, outputs a control voltage to a corresponding coherent light synthesis unit by the host computer, and demodulates the voltage signal by using a demodulator to realize laser communication. The laser signal receiving device can effectively cope with the wavefront distortion problem caused by atmospheric turbulence and transmission path differences, reduce random changes in the phases of each channel, reduce time differences and phase differences of signals received by different apertures, thereby improving the coherence of the signals, improving the synthesis efficiency, and optimizing the performance of laser communication.

[0069] Embodiment three. The laser communication device is constructed based on the device in embodiment one or two, and includes:

[0070] An APT module, which constructs an APT system, is used to execute the first APT module and the second APT module;

[0071] A coherent aperture synthesis module, which constructs a coherent aperture synthesis system, is used to execute the first coherent aperture synthesis module and the second coherent aperture synthesis module;

[0072] The coherent aperture synthesis system further comprises a circulator, which is used to isolate the transceiving signals;

[0073] A modulation and demodulation module, which constructs a modulation and demodulation system, is used to execute the modulation module and the demodulation module.

[0074] In the prior art, the traditional single-aperture receiving technology has the defects of limited aperture gain and weak anti-interference ability, and the transceiving gain and signal strength are weak. The coherent aperture synthesis technology has high requirements for phase control accuracy, and when long-distance transmission, atmospheric turbulence will introduce random and dynamic wavefront distortion, which is difficult to accurately match the phase difference of each light beam in real time, resulting in a significant decrease in the far-field coherence of the synthesized light beam. Moreover, the existing coherent aperture synthesis technology usually uses complex components such as fiber combiner, relay optical path and large deflection angle optical phased array antenna, which has high system complexity. At the same time, due to the dependence on a single phase compensator for centralized phase regulation of all input light beams, there is a link attenuation problem when long-distance transmission.

[0075] If the cascaded coherent light synthesis unit is directly applied to the laser communication device, it may cause spatial light to fiber coupling mismatch, resulting in input source distortion. The cascaded coherent light synthesis unit relies on the stable coherent light signal in the optical fiber, while the spatial light will have spot shift and wavefront distortion after passing through the atmospheric turbulence, which cannot be accurately coupled to the optical fiber and will also destroy the phase matching condition of the cascaded module, resulting in power leakage of the 3-dB optical fiber coupler and a significant decrease in coherent synthesis efficiency.

[0076] To solve the above technical problems, the embodiment provides a laser communication device, as shown in Figure 1 In the embodiment, there are APT (acquisition, pointing and tracking) system, coherent aperture synthesis system and modulation and demodulation system, respectively. The APT system is designed to achieve high-precision optical control of dynamic targets, and the core is to complete a series of coherent operations such as "finding the target", "aligning the target" and "continuously tracking the target", as shown in Figure 2 The APT system and the coherent aperture synthesis system cooperate to solve the coupling mismatch. The APT system further drives the precision servo mechanism and performs wavefront correction. The turntable servo mechanism compensates for the platform attitude disturbance to avoid optical axis shift. The wavefront corrector corrects the wavefront distortion caused by atmospheric turbulence to optimize the incident light quality. The multiple collimators ensure efficient coupling of spatial light to optical fiber, providing stable coherent light input for the cascaded coherent light synthesis unit, and solving the input source distortion problem from the source.

[0077] In operation, first enters the capture phase, APT system according to the preset target information, drive the platform carrying optical load pointing to the expected airspace. Using wide field of view, low resolution sensor to carry out scanning search. In this process, the beacon light emitted by the beacon light can be used as a stable and easy to identify optical beacon, greatly simplifies the process of identifying and preliminary confirming the target from complex background noise. Relying on the image data collected by COMS camera, APT system can quickly lock the beacon light position through real-time image processing algorithm.

[0078] When the target is successfully captured, the system immediately enters the aiming phase. The beacon light provides a crucial phase reference for the APT system, and the wavefront information it carries enables the APT system to accurately measure and analyze the small deviation of the target relative to the optical center axis of the system, including the error introduced by atmospheric turbulence and other path disturbances. Based on the real-time image from the COMS camera and the error signal, the APT system further drives the precision servo mechanism and performs wavefront correction. Based on the real-time image from the COMS camera and the error signal, the APT system first drives the servo mechanism for high-speed fine tuning, compensates for the macroscopic deviation and low-frequency jitter of the target in the field of view, and locks the target in the center of the sensor field of view, laying a solid foundation for subsequent coherent aperture synthesis and other operations requiring high phase stability.

[0079] The embodiment uses coherent light synthesis units for cascading to complete the coupling of sixteen apertures. In order to realize stable coherent light synthesis, a circulator is added to isolate the transmit and receive signals.

[0080] Therefore, the embodiment uses coherent aperture synthesis technology, constructs multiple coherent light synthesis units for cascading, accurately regulates the phase of each coherent light synthesis unit, realizes dynamic tracking and compensation of rapid random phase fluctuations caused by turbulence, and still maintains stable communication under the influence of atmospheric turbulence. The embodiment not only avoids the limitations of traditional centralized control, but also has faster convergence speed and stronger anti-interference ability, significantly improving the coherence quality of the synthesized light beam and the stability of the system.

[0081] Compared with the traditional coherent synthesis system, the embodiment realizes the integration design of the transmitting and receiving devices by isolating the transmitting signal and the receiving signal through the circulator, and has the advantages that the overall architecture of the system can be greatly simplified, the problems of large size and complex layout caused by the need to respectively configure independent optical paths, structural supports and control modules for the traditional separate transmitting and receiving devices are avoided, the system is more suitable for application scenarios with strict requirements on space size, and the stability and overall performance of the coherent synthesis are further improved. In addition, compared with the traditional Nxl combiner, the cascaded mode of the plurality of 3-dB fiber couplers has faster phase convergence speed and stronger anti-interference ability, and significantly improves the coherent quality of the synthesized light beam and the system stability.

[0082] Embodiment four. The embodiment is a further limitation of the laser communication device of embodiment three, wherein the coherent light synthesis unit comprises an input end , an input end , an output end , an output end , a fiber coupler and a phase shifter.

[0083] The input end carries a phase shifter for phase control, and the incident light signals enter the fiber coupler for coupling through the input end and the input end . The coupled incident light signals are output by the output end and the output end .

[0084] In the embodiment, the fiber coupler is a 3-dB fiber coupler.

[0085] When the 3-dB fiber coupler receives signal light from two input ports, according to the coupling mode theory, the optical power output from the two output ports can be represented as:

[0086]

[0087]

[0088] wherein, and are the optical powers of the input beams of the input end and the input end , respectively, is the phase difference between the input beams of the input end and the input end , wherein, and are the phases of the input beams of the input end and the input end , respectively. ​

[0089] The phase shifter is arranged to perform phase control, specifically:

[0090] Ensure that the input end The optical power of the incident light signal of the input end and the input end The phase difference is:

[0091] ;

[0092] Wherein, is an integer.

[0093] When the phase difference between the input end and the input end meets the above formula, and the optical power of the input beam is the same ( = ), all the optical power is output from the output end , and no optical power is leaked from the output end .

[0094] As Figure 3 shown, based on the above theory, the input end arranges a PS (phase shifter) for phase control, the input end is another input port, and the two input light signals are coupled through a 3-dB fiber coupler with a coupling ratio of 50 / 50. Finally, it is output through the output end and the output end , forming a coherent light synthesis unit.

[0095] The phase control is built with FPGA (Field Programmable Gate Array) and 32-bit ARM (microcontroller) as the hardware core, and the phase shifter is controlled by the corresponding analog voltage to compensate for the phase difference of the input light beam in each coherent light synthesis unit. High-frequency phase update can be realized to meet the real-time dynamic phase adjustment requirements.

[0096] However, the polarization of spatial light will drift after passing through atmospheric turbulence, which will cause the coupling ratio of the 3-dB fiber coupler to be unbalanced, the communication error rate to rise, and the joint interference of platform vibration and atmospheric turbulence to be unable to be cooperatively offset, resulting in frequent light interruption of the cascaded module and poor link stability. In order to solve the above technical problems, the present embodiment increases a PC (polarization controller) in the cascaded coherent light synthesis unit to keep the polarization state of the signal light stable, the polarization controller monitors and corrects the polarization drift of the incident light in real time, the polarization maintaining fiber avoids polarization crosstalk in the transmission process, and the polarization state parameters are included in the feedback system of the SPGD algorithm, which works with the phase shifter to ensure that the 3-dB coupler always maintains a stable coupling ratio, and solves the problem of error rate caused by polarization imbalance.​

[0097] Implementation Method 5. This implementation method further defines the laser communication device described in Implementation Method 3. When receiving a signal, the device uses a compensation algorithm to compensate for the phase difference in real time based on the voltage signal.

[0098] In this embodiment, the SPGD algorithm is used to compensate for the phase difference in real time based on the voltage signal converted by the photodetector.

[0099] First, the photodetector converts the received optical signal into a corresponding voltage signal. This voltage signal directly reflects the current phase matching state of the beam. The SPGD algorithm applies positive and negative perturbations and synchronously records the voltage change output by the photodetector after the perturbation. The gradient update direction is calculated based on the voltage change. When the gradient drops to the threshold, it indicates that the current phase has been adjusted to the optimal matching state and the phase difference has been effectively canceled. At this point, the algorithm stops iterating and completes the real-time compensation of the phase difference.

[0100] In summary, such as Figure 4 As shown, the coherent aperture synthesis module and modulation / demodulation module described in this embodiment constitute a 16-aperture transceiver array based on coherent synthesis. In this embodiment, during signal transmission and reception, the APT system drives a precision servo mechanism to perform wavefront correction. Simultaneously, the target information is locked at the center of the sensor's field of view based on the APT system. By integrating the coherent energy of multiple sub-beams through the 16-aperture transceiver array based on coherent synthesis, coherent synthesis between multiple apertures is achieved, forming a laser communication device with high power and strong anti-interference capability. Furthermore, by precisely controlling the phase of each aperture, the system power can be adjusted, significantly improving the system's transceiver gain. The circulator is integrated into the coherent aperture synthesis module to isolate the transceiver signals, enabling bidirectional communication and avoiding redundant structures. The host computer simultaneously receives turbulence data from the APT system and optical power data from the coherent synthesis aperture module, dynamically adjusts the phase shifter, and provides early warning to the APT system. This improves synthesis efficiency and enhances anti-interference capability, achieving a dual optimization of "prediction + real-time correction".

[0101] Implementation Method Six. A laser communication method according to this implementation method, the method being implemented based on the device described in Implementation Method Three, includes the following steps:

[0102] Step 1: When transmitting and receiving signals, the APT system is used to drive the precision servo mechanism to perform wavefront correction, and the target information is locked at the center of the sensor's field of view based on the APT system.

[0103] Step 2: Optical path coupling of the transmit and receive signals is performed using a coherent aperture synthesis system, and the transmit and receive signals are isolated by a circulator;

[0104] Step 3: Modulate or demodulate the transmit and receive signals respectively based on the modulation and demodulation system, specifically as follows:

[0105] When transmitting signals, the coherent signal light generated by the laser is modulated by the modulator, and the modulated coherent signal light is transmitted to the cascaded coherent light synthesis unit for optical path coupling, and the corresponding optical path coupled coherent signal light is output by the plurality of collimators;

[0106] When receiving signals, the incident light signal is transmitted to the cascaded coherent light synthesis unit for optical path coupling by the plurality of collimators, the optical path coupled incident light signal is converted into a voltage signal based on the photodetector, the voltage signal converted by the photodetector is demodulated by the demodulator, and laser communication is realized.

[0107] In the signal transmission process in the embodiment, the laser first generates coherent signal light, the coherent signal light is encoded and modulated by the modulator to carry transmission information, the modulated optical signal is isolated by the circulator to ensure that the transmission and reception channels do not interfere with each other, and finally transmitted to the cascaded coherent light synthesis unit for coupling. The coherent signal light after coupling is output by the plurality of collimators.

[0108] At the receiving end, the incident light signal is guided to the receiving path by the same circulator, and the incident light signal is converted into a voltage signal by the PD (photodetector) and uploaded to the host computer. The voltage signal value is used as the feedback input of the SPGD algorithm for real-time phase correction. At the same time, the demodulator analyzes and reconstructs the received electrical signal, thereby accurately recovering the original transmission information.

[0109] The embodiment is expected to be further expanded and applied in many fields. In the field of communication, with the continuous growth of the demand for high-speed and large-capacity data transmission, it can be used to improve the performance of free space optical communication system, overcome the influence of atmospheric channel on signal transmission, and improve the communication quality and transmission distance. In the aspect of remote sensing detection, it can enhance the detection capability of optical remote sensing equipment and realize high-resolution imaging of remote targets, which is helpful to obtain more rich and accurate target information. In addition, through the integration with emerging technologies such as artificial intelligence, it is expected to further optimize the system performance and realize more innovative applications, providing strong support for the development of related fields.

[0110] The above describes in detail a multi-aperture coherent synthesis optical phased array laser communication device and method. The principles and implementation modes of the present application are described by applying specific examples. The above examples are only used to help understand the method and core idea of the present application. For those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In view of the above, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A laser communication device, characterized in that, The device includes: The APT module constructs the APT system, which is used to execute the first APT module and the second APT module. A coherent aperture synthesis module constructs a coherent aperture synthesis system for executing the first coherent aperture synthesis module and the second coherent aperture synthesis module. The coherent aperture synthesis system also includes a circulator for isolating transmitted and received signals; The modulation and demodulation module constructs the modulation and demodulation system and is used to execute the modulation and demodulation modules. The first APT module, when transmitting signals, uses the first APT system to drive the precision servo mechanism to perform wavefront correction, and at the same time locks the target information at the center of the sensor's field of view based on the first APT system; The first coherent aperture synthesis module constructs the first coherent aperture synthesis system, including a host computer, multiple collimators and multiple coherent light synthesis units. The multiple coherent light synthesis units are cascaded, and the cascaded coherent light synthesis units are used to perform optical path coupling on the modulated coherent signal light. The host computer outputs an analog voltage to the corresponding coherent light combining unit; The plurality of collimators are used to output coherent signal light after optical path coupling; The modulation module modulates the coherent signal light generated by the laser when transmitting a signal, and uses a modulator to carry the transmitted information. The second APT module, when receiving signals, uses the second APT system to drive the precision servo mechanism to perform wavefront correction, and at the same time locks the target information at the center of the sensor's field of view based on the second APT system; The second coherent aperture synthesis module constructs a second coherent aperture synthesis system, including a host computer, a photodetector, multiple collimators and multiple coherent light synthesis units. The multiple coherent light synthesis units are cascaded, and the incident light signal is optically coupled using the cascaded coherent light synthesis units. The host computer is used to receive the voltage signal converted by the photodetector and output the control voltage to the corresponding coherent light combining unit. The photodetector is used to convert the incident light signal after optical path coupling into a voltage signal; The plurality of collimators are used to transmit the incident light signal to the corresponding coherent light combining unit, respectively. The demodulation module, when receiving a signal, uses a demodulator to demodulate the voltage signal converted by the photodetector to recover the original transmitted information; The coherent light combining unit includes an input terminal. Input end Output terminal Output terminal Fiber optic couplers and phase shifters; The input terminal Phase modulation is achieved by using a phase shifter, and the incident light signals pass through the input terminals respectively. and input terminal The incident light signal is coupled into the fiber optic coupler, and the coupled incident light signal is output from the fiber optic coupler. and output terminal Output.

2. The laser communication device according to claim 1, characterized in that, The phase modulation using the phase shifter is specifically as follows: Ensure input end and input terminal The incident light signal has the same optical power, and the input end is ensured to be the same. and input terminal The phase difference is: ； in, It is an integer.

3. The laser communication device according to claim 1, characterized in that, The coupling ratio of the fiber optic coupler is 50 / 50.

4. A laser communication device according to claim 1, characterized in that, When receiving a signal, the device uses a compensation algorithm to compensate for the phase difference in real time based on the voltage signal.

5. A laser communication device according to claim 1, characterized in that, The coherent aperture synthesis module also includes a polarization controller and a polarization-maintaining fiber, which are used to maintain the stability of the polarization state of the signal light.

6. A laser communication method, said method being implemented based on the device of claim 1, characterized in that, Includes the following steps: Step 1: When transmitting and receiving signals, the APT system is used to drive the precision servo mechanism to perform wavefront correction, and the target information is locked at the center of the sensor's field of view based on the APT system. Step 2: Optical path coupling of the transmit and receive signals is performed using a coherent aperture synthesis system, and the transmit and receive signals are isolated by a circulator; Step 3: Modulate or demodulate the transmit and receive signals respectively based on the modulation and demodulation system, specifically as follows: When transmitting a signal, the coherent signal light generated by the laser is modulated by a modulator, and the modulated coherent signal light is transmitted to a cascaded coherent light combining unit for optical path coupling. Multiple collimators are used to output the corresponding optically coupled coherent signal light. When receiving signals, multiple collimators are used to transmit the incident light signal to a cascaded coherent light combining unit for optical path coupling. The incident light signal after optical path coupling is converted into a voltage signal based on a photodetector. The voltage signal converted by the photodetector is demodulated by a demodulator to realize laser communication.

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