Rapid link building laser communication method and system based on optical phased array

Abstract

The invention relates to the technical field of wireless laser communication, and particularly discloses a rapid link building laser communication method and system based on an optical phased array. The invention discloses a rapid link building laser communication system based on an optical phased array. The system comprises an active transmitting terminal and a cat eye reverse modulation laser communication terminal, the active transmitting terminal is used for transmitting an uplink optical signal and comprises a control processing unit, a laser driver, a laser, a collimation beam expander and a spatial light modulator which are arranged in sequence; the cat eye reverse modulation laser communication terminal is used for receiving an uplink optical signal and feeding back a downlink optical signal, and comprises a cat eye optical system, a spectroscope, a spatial light modulator, a second photoelectric detector and a control processing unit. The problem that a link of an existing wireless laser communication system is difficult to establish is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless laser communication, and in particular to a method and system for fast link establishment laser communication based on an optical phased array. Background Art

[0002] With the development of information technology, the demand for high-speed and secure data transmission is becoming increasingly urgent. Traditional microwave links, due to limitations such as limited bandwidth and susceptibility to interference, cannot meet the requirements for information transmission under conditions of strong electromagnetic interference. Wireless laser communication, which uses lasers as communication carriers, offers advantages such as high security and strong resistance to electromagnetic interference, making it a key development direction for secure communication under conditions of strong electromagnetic interference.

[0003] Existing typical wireless laser communication systems are limited by the beam divergence angle, requiring two communication terminals to establish a communication link through a complex process of aiming, capturing, and tracking. This results in low link establishment efficiency, severely limiting the applicability of wireless laser communication. Designing a laser communication system that can quickly establish a link is an effective means of transmitting high-capacity, high-speed, and secure data under strong electromagnetic interference conditions. Summary of the Invention

[0004] In order to solve the problem of difficulty in establishing links in existing wireless laser communication systems, the first purpose of the present invention is to provide a fast link establishment laser communication system based on an optical phased array, which adopts an active transmitting terminal based on an optical phased array and a large field of view cat's eye reverse modulation laser communication terminal based on the cat's eye effect as active and passive information nodes respectively. The optical phased array technology is used to improve the active end capture, tracking and alignment process, and the reverse modulation technology is used to eliminate the capture, tracking and aiming process of the passive information node, which can greatly reduce the link establishment time and achieve fast link establishment.

[0005] The second object of the present invention is to provide a fast link-building laser communication method based on an optical phased array.

[0006] To achieve the first objective, the first technical solution of the present invention is: a fast link establishment laser communication system based on an optical phased array, comprising an active transmitting terminal and a cat's eye reverse modulation laser communication terminal;

[0007] The active transmitting terminal is used to transmit an uplink optical signal, and includes a control processing unit, a laser driver, a laser, a collimating beam expander, and a spatial light modulator arranged in sequence;

[0008] The cat's eye reverse modulation laser communication terminal is used to receive uplink optical signals and feed back downlink optical signals, and includes a cat's eye optical system, a spectroscope, a spatial light modulator, a second photodetector and a control processing unit.

[0009] Preferably, the active transmitting terminal is also used to receive downlink optical signals, and further comprises a large-field-of-view receiving lens, a first photodetector and a signal acquisition unit which are sequentially arranged along the direction of the downlink optical signal.

[0010] Preferably, the active transmitting terminal further includes a phase controller for performing phase shift control on the spatial light modulator, and receiving and transmitting phase shift signals according to the electrical signals of the control processing unit and the spatial light modulator.

[0011] Preferably, the spatial light modulator regulates the phase of each point in the uplink plane wave space to form an uplink communication light beam that is emitted to the cat's eye optical system.

[0012] Preferably, in the cat's eye reverse modulation laser communication terminal, the uplink communication light beam passes through the cat's eye optical system and is split by a spectroscope to form two uplink light signals, which are respectively focused on the spatial light modulator and the second photodetector.

[0013] Preferably, the second photodetector forms a detection signal, which is used to generate a downlink modulation signal through a control processing system, and controls the spatial light modulator to form a reverse modulated reflected light signal.

[0014] Preferably, the scanning range of the uplink communication light beam generated by the active transmitting terminal can cover the uncertain area where the cat's eye reverse modulation laser communication terminal is located and the receiving field of view of the large field of view receiving lens.

[0015] Preferably, the active transmitting terminal is located within the effective field of view angle range of the large field of view cat's eye reverse modulation laser communication terminal.

[0016] Preferably, the laser is a narrow linewidth laser.

[0017] To achieve the second objective, the second technical solution of the present invention is: a fast link establishment laser communication method based on an optical phased array, comprising:

[0018] The control processing unit in the active transmitting terminal controls the laser to emit an uplink communication laser through a laser driver. The communication laser is converted into an uplink plane wave by a collimating beam expander and irradiated to a spatial light modulator. The phase controller generates a specific phase shift signal to control the spatial light modulator to adjust the phase of each point in the uplink plane wave space, forming an uplink communication beam.

[0019] The uplink communication beam scans the uncertain area. When it scans the cat's eye reverse modulation laser communication terminal, the uplink communication beam is split by a spectroscope through the cat's eye optical system and focused on the spatial light modulator and the second photodetector respectively.

[0020] The second photoelectric detector generates a detection signal which is then processed by the control processing system to generate a downlink modulation signal;

[0021] The control spatial light modulator forms a reverse modulated reflected light signal, which is reflected through the cat's eye optical system to the large field of view receiving lens in the active transmitting terminal, focused on the first photodetector for photoelectric conversion, and sent to the control processing unit for processing to complete the link establishment.

[0022] Beneficial effects of the above technical solution:

[0023] The present invention provides a fast link-establishing laser communication system based on an optical phased array. The active transmitting terminal based on the optical phased array uses a spatial light modulator to control the phase of each point in the plane wave space, quickly forming a specific directional beam to scan the uncertain area where the passive terminal is located. This example system can complete scanning coverage of 32×32 equally spaced points within a 0.21°×0.21° range within 1 second.

[0024] Because the large-field-of-view cat's eye reverse modulation laser communication terminal based on the cat's eye effect utilizes the original path return characteristic of the incident communication beam to ensure that the reverse reflected communication beam can always strictly return to the active terminal, thereby eliminating the scanning and tracking process of the cat's eye terminal and can quickly establish a communication link with the active terminal within the field of view. In this example, the active transmitting terminal based on the optical phased array can quickly establish a link with a large-field-of-view cat's eye reverse modulation laser communication terminal based on the cat's eye effect located within an uncertainty range of 0.21°×0.21° within 1 second.

[0025] Based on the cat's eye effect, the downlink OOK signal transmission of the large field of view cat's eye reverse modulation laser communication terminal is actually measured at 500kbps OOK signal. Figure 3 The entire link lasted approximately three minutes, with error-free transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic diagram of the structure of a fast link establishment laser communication system based on an optical phased array provided in one embodiment of the present invention;

[0028] Figure 2 An embodiment of the present invention provides an uplink scanning beam formed by an active transmitting terminal based on an optical phased array through a spatial light modulator;

[0029] Figure 3A 500 kbps OOK signal is experimentally transmitted according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following further describes the implementation methods of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless there is a conflict.

[0031] The terms "first," "second," and the like (if any) in the specification and claims are used to distinguish similar objects and are not necessarily used to describe a particular order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated (if any) or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0032] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0033] Example 1

[0034] An embodiment of the present invention provides a fast link establishment laser communication system based on an optical phased array, the structural diagram of which is shown in FIG. Figure 1As shown. It includes an active transmitting terminal 1 and a cat's eye reverse modulation laser communication terminal 2. The control processing unit 1-0 in the active transmitting terminal 1 based on the optical phased array is an industrial control computer. The industrial control computer generates a TTL signal with a maximum modulation frequency of 3KHz and inputs the TTL signal to the external trigger port of the laser driver 1-1. The laser 1-2 used in this embodiment adopts a 532nm semiconductor single longitudinal mode continuous laser with an output power of 50mW, a divergence angle of 1mrad, and a beam diameter of 1.2mm. The collimating beam expander 1-4 has an output diameter of 20mm and a transmittance of 95%; the spatial light modulator 1-6 adopts a liquid crystal spatial light modulator from Meadowlark Optics with a response time of less than 0.6ms, a resolution of 1024×1024, an aperture of 17.4mm×17.4mm, and a unit size of 17μm; the phase controller 1-7 adopts a matching controller, which can control the phase control range of the spatial light modulator 1-6 to be 0~2π. The wide-field-of-view receiving lens 1-10 has a receiving aperture of 20mm, a transmittance of 90%, and a field of view of 5mrad. The first photodetector 1-11 uses a Thorlabs silicon photodiode with a minimum detectable power of 100nW. The cat's eye optical system 2-1 in the wide-field-of-view cat's eye reverse modulation laser communication terminal 2, based on the cat's eye effect, has a diameter of 2cm, an effective field of view of 30°, and a transmittance of 90%. The beam splitter 2-2 has a transmittance of 90% and a reflectivity of 10%. A microelectromechanical system array is placed in the focal plane as a spatial light modulator 2-3, a four-quadrant detector is used as the second photodetector 2-4, and an FPGA is used as the control and processing system 2-6.

[0035] When the system is working, the active transmitting terminal 1 based on the optical phased array is controlled by an industrial control computer as the processing unit 1-0. The large-field cat's eye reverse modulates the laser communication terminal 2 based on the cat's eye effect and the prior knowledge of the orientation. According to the agreed capture, tracking and aiming protocol, a TTL coded communication pulse signal is generated and input into the driver 1-1 to control the laser 1-2 to emit an uplink communication laser 1-3 in the form of a pulse. The uplink communication laser 1-3 is transformed into an uplink plane wave 1-5 through the collimating beam expander 1-4 and irradiated at a vertical angle to the liquid crystal spatial light modulator 1-6. According to the capture, tracking and aiming strategy, a specific phase shift signal 1-8 is generated through the phase controller 1-7 to control the spatial light modulator 1-6 to adjust the phase of each point in the space of the uplink plane wave 1-5, forming an uplink communication beam 1-9 to quickly scan the uncertain area. Figure 2The present invention employs an active transmitting terminal based on an optical phased array to form an uplink scanning beam through a spatial light modulator. When scanning a large-field-of-view cat's-eye reverse-modulated laser communication terminal 2 based on the cat's-eye effect, the uplink communication beam 1-9 is focused by a spectroscope 2-2 onto a spatial light modulator 2-3 and a second photodetector 2-4 located at the focal plane. The second photodetector 2-4 generates a detection signal 2-5, which is processed and analyzed by a control processing unit 2-6, which is an FPGA control processing system. After processing and analysis by the control processing unit 2-6, a downlink modulation signal 2-7 is generated according to the agreed capture, tracking, and aiming protocol. The spatial light modulator 2-3 is controlled to generate a reverse-modulated optical signal 2-8, which is reflected back through the cat's-eye optical system 2-1 to the active transmitting terminal 1 based on the optical phased array. The reverse-modulated optical signal 2-8 is received by a large-field-of-view receiving lens 1-10, focused on a photodetector 1-11, and then sent to the control processing unit 1-0 for processing, completing the link establishment. Based on the cat's eye effect, the downlink OOK signal transmission of the large field of view cat's eye reverse modulation laser communication terminal is actually measured at 500kbps OOK signal. Figure 3 The entire link lasted approximately three minutes, with error-free transmission.

[0036] The present invention also provides a method for rapid laser communication link establishment using a rapid laser communication system based on an optical phased array. Link establishment is accomplished using a rapid laser communication system based on an optical phased array; the method includes: a control processing unit 1-0 in an active transmitting terminal 1 controls a laser 1-2 via a laser driver 1-1 to emit an uplink communication laser 1-3; the communication laser 1-3 is transformed into an uplink plane wave 1-5 by a collimating beam expander 1-4 and irradiated onto a spatial light modulator 1-6; a phase controller 1-7 generates a specific phase shift signal 1-8 to control the spatial light modulator 1-6 to adjust the phase of each spatial point of the uplink plane wave 1-5, thereby forming an uplink communication beam 1-9. The uplink communication beam 1-9 scans an uncertain region. When it scans a cat's eye reverse modulation laser communication terminal 2, the cat's eye optical system 2-1 splits the uplink communication beam 1-9 via a beam splitter 2-2, focusing the beams onto the spatial light modulator 2-3 and the second photodetector 2-4, respectively. The second photodetector 2-4 generates a detection signal 2-5, which is then passed through the control processing system 2-6 to generate a downlink modulated signal 2-7. The spatial light modulator 2-3 is controlled to generate a reverse modulated reflected light signal 2-8, which is reflected along the original path through the cat's eye optical system 2-1 to the large field of view receiving lens 1-10 in the active transmitting terminal 1. The signal is then focused on the first photodetector 1-11 for photoelectric conversion and sent to the control processing unit 1-0 for processing, completing the link establishment.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A fast link establishment laser communication system based on optical phased array, characterized in that: It includes an active transmitting terminal (1) and a cat's eye reverse modulation laser communication terminal (2); The active transmitting terminal (1) is used for transmitting an uplink optical signal, and comprises a control processing unit (1-0), a laser driver (1-1), a laser (1-2), a collimating beam expander (1-4), and a spatial light modulator (1-6) which are arranged in sequence; The cat's eye reverse modulation laser communication terminal (2) is used for receiving uplink optical signals and feeding back downlink optical signals, and comprises a cat's eye optical system (2-1), a spectroscope (2-2), a spatial light modulator (2-3), a second photodetector (2-4), and a control processing unit (2-6).

2. The optical phased array-based fast link establishment laser communication system according to claim 1, characterized in that: The active transmitting terminal (1) is also used for receiving downlink optical signals, and further comprises a large-field-of-view receiving lens (1-10), a first photoelectric detector (1-11), and a signal acquisition unit (15) which are sequentially arranged along the direction of the downlink optical signal.

3. The optical phased array-based fast link establishment laser communication system according to claim 1, characterized in that: The active transmitting terminal (1) further includes a phase controller (1-7) for performing phase shift control on the spatial light modulator (1-6) and receiving and transmitting a phase shift signal (1-8) according to the electrical signals of the control processing unit (1-0) and the spatial light modulator (1-6).

4. The optical phased array-based fast link establishment laser communication system according to claim 3, characterized in that: The spatial light modulator (1-6) regulates the phase of each spatial point of the uplink plane wave (1-5) to form an uplink communication light beam (1-9) which is emitted to the cat's eye optical system (2-1).

5. The optical phased array-based fast link establishment laser communication system according to claim 1, characterized in that: In the cat's eye reverse modulation laser communication terminal (2), an uplink communication light beam (1-9) passes through the cat's eye optical system (2-1), is split by a spectroscope (2-2) to form two uplink light signals, and are respectively focused on the spatial light modulator (2-3) and the second photodetector (2-4).

6. The optical phased array-based fast link establishment laser communication system according to claim 5, characterized in that: The second photodetector (2-4) forms a detection signal (2-5), which is then processed by a control processing system (2-6) to generate a downlink modulation signal (2-7), which controls the spatial light modulator (2-3) to form a reverse modulated reflected light signal (2-8).

7. The optical phased array-based fast link establishment laser communication system according to claim 5, characterized in that: The scanning range of the uplink communication light beam (1-9) generated by the active transmitting terminal (1) can cover the uncertain area where the cat's eye reverse modulation laser communication terminal (2) is located and the receiving field of view of the large field of view receiving lens (1-10).

8. The optical phased array-based fast link establishment laser communication system according to claim 1, characterized in that: The active transmitting terminal (1) is located within the effective viewing angle range of the large-viewing-field cat's-eye reverse modulation laser communication terminal (2).

9. The optical phased array-based fast link establishment laser communication system according to claim 1, characterized in that: The laser (1-2) is a narrow linewidth laser.

10. A fast link establishment laser communication method based on optical phased array, characterized in that: A fast link establishment laser communication system based on an optical phased array according to any one of claims 1 to 9 is used to complete link establishment; comprising: A control processing unit (1-0) in an active transmitting terminal (1) controls a laser (1-2) to emit an uplink communication laser (1-3) via a laser driver (1-1); the communication laser (1-3) passes through a collimating beam expander (1-4) to become an uplink plane wave (1-5), which is then irradiated onto a spatial light modulator (1-6); a phase controller (1-7) generates a specific phase shift signal (1-8) to control the spatial light modulator (1-6) to regulate the phase of each spatial point of the uplink plane wave (1-5), thereby forming an uplink communication light beam (1-9); The uplink communication light beam (1-9) scans the uncertain area, and when it scans the cat's eye reverse modulation laser communication terminal (2), the uplink communication light beam (1-9) is split by a spectroscope (2-2) through a cat's eye optical system (2-1) and focused on a spatial light modulator (2-3) and a second photodetector (2-4) respectively; The second photodetector (2-4) generates a detection signal (2-5) which is then processed by a control processing system (2-6) to generate a downlink modulation signal (2-7); The control spatial light modulator (2-3) forms a reverse modulated reflected light signal (2-8), which is reflected through the original path of the cat's eye optical system (2-1) to the large field of view receiving lens (1-10) in the active transmitting terminal (1), focused on the first photodetector (1-11) for photoelectric conversion, and sent to the control processing unit (1-0) for processing, thereby completing the link establishment.

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