Miniaturized satellite-ground laser communication terminal based on single-photon detection technology

Abstract

The invention discloses a miniaturized satellite-ground laser communication terminal based on a single-photon detection technology, which belongs to the technical field of optical communication equipment and consists of seven light paths, the optical paths are respectively an observation receiving optical path A, a signal transmitting optical path B, a near-infrared beacon receiving optical path C, a short-wave infrared beacon receiving optical path D, a single-photon signal receiving optical path E, a single-photon beacon receiving optical path F and a beacon transmitting optical path G, and the optical paths jointly finish receiving, transmitting and detecting of single-photon / non-single-photon beacon light / signal light. The terminal can be used for satellite-ground laser communication, and compared with a traditional satellite-ground laser communication terminal, the antenna aperture is reduced by 20-30%, the size is only 20% of that of the traditional satellite-ground terminal, and the weight can be reduced by 80%; and meanwhile, satellite-ground transmission can be completed, ground point-to-point laser communication capability can be compatible, the application range of the laser communication ground station is greatly expanded, and the laser communication ground station can be widely applied to air-ground, satellite-ground, deep space and ground point-to-point laser communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communication equipment, and in particular relates to a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology. Background Art

[0002] Compared with the existing microwave communication technology, satellite laser communication technology has significant advantages such as high data rate, anti-interference and good confidentiality, and is an effective supplementary technical means for satellite communication in the future. At present, many satellite optical communication on-orbit tests have been carried out at home and abroad, and military and commercial aerospace applications are gradually being carried out.

[0003] Compared with traditional microwave communication systems, laser communication systems are superior in that they use light wave bands as information carriers (carrier 10~400THz), have extremely high communication bandwidth, and have the outstanding advantages of light weight, small size, and low power consumption.

[0004] The laser communication antenna is responsible for completing the whole star, beam divergence compression and directional emission of the transmitted signal / beacon light; at the same time, it completes the collection, beam splitting and focusing of the received signal / beacon light on the corresponding detector. The traditional laser communication system uses PIN, PD, APD and other devices, and the photosensitive material is InGaAs or GaAs, and its sensitivity is generally 40~42dBm@10Gbpa; while the spot position detector is a CCD or CMOS device, and the photosensitive surface material is InGaAs or Si material, and its sensitivity is -60~65dBm. The sensitivity is relatively low, the terminal optical antenna aperture needs to be relatively large (500mm~1600mm), the terminal volume (6~20m³), weight (2~10t) and power consumption are all large, so that the traditional laser communication ground station needs to be built on a fixed house or a large-sized load-carrying vehicle, which seriously restricts the application scope of the laser communication ground terminal. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention proposes a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology, which adopts single-photon positioning detectors and single-photon communication detectors as the position and communication detectors of laser communication, greatly improving the system detector sensitivity (-75~-80dBm), while realizing small-aperture reception (150~200mm), and significantly reducing the system weight (from 2~8t to 400kg), thereby reducing the system cost. At the same time, as the weight is reduced, the terminal can be carried and transported by a small car, which can not only realize satellite-to-ground communication transmission, but also realize ground point-to-point high-speed laser transmission between fixed points and fixed points, and fixed points and exciting points as the volume becomes smaller, greatly expanding the application scope of laser communication ground terminals.

[0006] The above purpose is achieved through the following technical solutions: A miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology includes the following optical components: Main telescope, reflector 1, filter 1, coarse beacon receiving lens group, coarse beacon detector, reflector 2, reflector 5, compensation mirror group, fine tracking mirror 1, reflector 3, two-way angle reflection prism group, reflector 4, reflector 6, light trap, beam splitter 3, signal transmitting mirror group, signal light source, filter 2, fine beacon 1 receiving mirror group, fine beacon 1 detector, fine tracking mirror 2, beam splitter 1, filter 3, fine beacon 2 receiving mirror group, fine beacon 2 detector, optical lifter, beam splitter 2, single-photon beacon receiving filter, single-photon beacon receiving mirror group, single-photon positioning detector, single-photon signal receiving filter, single-photon signal receiving mirror group, single-photon communication detector, beacon / signal laser, beacon / signal transmitting antenna; The above optical components constitute the observation receiving optical path A, the signal transmitting optical path B, the near-infrared beacon receiving optical path C, the short-wave infrared beacon receiving optical path D, the single-photon signal receiving optical path E, the single-photon beacon receiving optical path F, and the beacon transmitting optical path G, wherein: The observation receiving optical path A consists of the main telescope, reflector 1, filter 1, coarse beacon receiving lens group, and coarse beacon detector. The external receiving light beam is collected and reduced by the main telescope, reflected by the incident reflector 1, and then enters the incident filter 1 and the coarse beacon receiving lens group, and finally enters the coarse beacon detector to complete the beacon light reception and positioning work. This optical path is used to measure the incident coarse beacon light; The signal transmission optical path B is composed of the main telescope, the second reflector, the fifth reflector, the compensation mirror group, the fine tracking mirror one, the third reflector, the fourth reflector, the sixth reflector, the beam splitter three, the signal transmission mirror group, and the signal light source. First, the signal light source sends the signal light of the specified wavelength, which is shaped by the signal transmission mirror group, transmitted by the beam splitter three, reflected by the sixth reflector, the fourth reflector, the third reflector, and the fine tracking mirror one, and then passes through the compensation mirror group and the fifth reflector, the second reflector, and then shaped and reduced by the main telescope before being emitted to the target. The near-infrared beacon receiving optical path C is composed of the main telescope, reflector 2, reflector 5, compensation mirror group, precision tracking mirror 1, reflector 3, reflector 4, reflector 6, beam splitter 3, filter 2, precision beacon 1 receiving mirror group, and precision beacon 1 detector. After the external beacon light is received and beam-contracted by the main telescope, it passes through reflector 5, precision tracking mirror 1, reflector 3, reflector 4, reflector 6, beam splitter 3 and is incident on filter 2 and precision beacon 1 receiving mirror group, and finally forms an image on the precision beacon 1 detector. This optical path uses the beacon light spot information on the precision beacon 1 detector to realize closed-loop tracking of the precision tracking mirror 1; The short-wave infrared beacon receiving optical path D is composed of the main telescope, reflector 2, reflector 5, compensation mirror group, precision tracking mirror 1, reflector 3, reflector 4, reflector 6, precision tracking mirror 2, beam splitter 1, filter 3, precision beacon 2 receiving mirror group, and precision beacon 2 detector. After the external short-wave infrared beacon light is received and beam-contracted by the main telescope, it passes through reflector 5, compensation mirror group, precision tracking mirror 1, reflector 3, reflector 4, reflector 6, precision tracking mirror 2, beam splitter 1 and is incident on filter 3 and precision beacon 2 receiving mirror group, and finally forms an image on the precision beacon 2 detector. This optical path uses the beacon light spot information on the precision beacon 2 detector to realize closed-loop tracking of precision tracking mirror 2; The single-photon signal receiving optical path E is composed of a main telescope, a reflector 2, a reflector 5, a compensation mirror group, a precision tracking mirror 1, a reflector 3, a reflector 4, a reflector 6, a precision tracking mirror 2, a beam splitter 1, an optical lifter, a beam splitter 2, a single-photon signal receiving filter, a single-photon signal receiving mirror group, and a single-photon communication detector. After the external communication light is received and beam-contracted by the main telescope, it passes through the reflector 5, the compensation mirror group, the precision tracking mirror 1, the reflector 3, the reflector 4, the reflector 6, the precision tracking mirror 2, and the beam splitter 1 and is incident on the optical lifter. After being reflected by the incident beam splitter 2, it is incident on the single-photon signal receiving filter and the single-photon signal receiving mirror group, and is finally focused on the incident single-photon communication detector, and the single-photon communication detector is used to realize the reception of the communication signal by the received signal light; The single-photon beacon receiving optical path F is composed of a main telescope, a reflector 2, a reflector 5, a compensating mirror group, a precision tracking mirror 1, a reflector 3, a reflector 4, a reflector 6, a precision tracking mirror 2, a beam splitter 1, an optical lifter, a beam splitter 2, a single-photon beacon receiving filter, a single-photon beacon receiving mirror group, and a single-photon positioning detector. After the external communication light is received and beam-contracted by the main telescope, it passes through the reflector 5, the compensating mirror group, the precision tracking mirror 1, the reflector 3, the reflector 4, the reflector 6, the precision tracking mirror 2, and the beam splitter 1 and is incident on the optical lifter. After being reflected by the beam splitter 2, it is incident on the single-photon beacon receiving filter and the single-photon beacon receiving mirror group, and finally forms an image on the single-photon positioning detector. The optical path uses the single-photon positioning information of the single-photon positioning detector to perform closed-loop tracking of the precision tracking mirror 2. Beacon transmission optical path: It consists of a beacon / signal laser and a beacon / signal transmitting antenna. The beacon light that meets the wavelength is emitted by the beacon laser and shaped and the beam divergence angle is compressed by the beacon / signal transmitting antenna. It is then sent toward the target along with the two-dimensional turntable of the theodolite.

[0007] Furthermore, the main telescope, reflector 1, filter 1, coarse beacon receiving lens group, coarse beacon detector, reflector 2, reflector 5, compensation mirror group, fine tracking mirror 1, reflector 3, two-way angle reflection prism group, reflector 4, beacon / signal laser, beacon / signal transmitting antenna are placed on the two-dimensional turntable of the theodolite; and the target tracking of the two-dimensional turntable of the theodolite is controlled by electrical position feedback of the light spot on the coarse beacon detector.

[0008] Furthermore, the main telescope is a Cassegrain telescope.

[0009] Furthermore, the two-way corner reflection prism set is inserted into the optical path through a servo mechanism, and the aperture of the two-way corner reflection prism set should be greater than 2 inches.

[0010] Furthermore, an adaptive optical component is added between the reflector four and the reflector six, and the adaptive optical component has 32 to 64 units.

[0011] Furthermore, the splitting ratio of the beam splitter 1 needs to be divided according to the sensitivity characteristics of the precision beacon 2 detector, the single photon communication detector, and the single photon positioning detector. ,in is the sensitivity of the precision beacon 2 detector, in dBm; is the sensitivity of the single-photon localization detector, in dBm; is the sensitivity of the single-photon communication detector in dBm.

[0012] Beneficial effects: 1. Compared with the traditional Kude optical path antenna, the satellite-to-ground laser communication terminal is designed with a large-field-of-view beacon receiving optical path that does not pass through the Kude optical path arm, which is used for receiving the large-field-of-view beacon of the target; the present invention adopts a two-stage fast-reflection mirror design of a precision tracking mirror one and a precision tracking mirror two, wherein the first-stage fast-reflection mirror is controlled by the beacon detector, and at the same time realizes compensation for the turntable optical path axis error, and the second-stage fast-reflection mirror is controlled by the precision beacon second detector or the single-photon positioning detector, and realizes compensation for the turntable coarse tracking and the tracking residual of the first-stage fast-reflection mirror; wherein the single-photon positioning detector includes but is not limited to a single-photon four-quadrant detector, and can also be other multi-pixel single-photon positioning detectors.

[0013] 2. The satellite-to-ground laser communication terminal of the present invention is designed with a bidirectional corner reflection prism group as a self-inspection mechanism. The bidirectional corner reflection prism group is inserted into the optical path through a servo mechanism, so that the system can perform coaxiality detection of optical paths such as the signal transmission optical path, the near-infrared beacon receiving optical path, the short-wave infrared beacon receiving optical path, the single-photon signal receiving optical path, and the single-photon beacon receiving optical path without relying on an external light source, thereby facilitating the use of the system.

[0014] 3. In order to solve the problem that the ultra-sensitive detection of single-photon detectors is extremely sensitive to noise, the present invention designs an optical trap to effectively clear the optical signal of the emission optical path to avoid false alarms of single-photon detectors.

[0015] 4. The present invention designs an optical riser to isolate the optical path behind the terminal from the single-photon detector, while providing azimuth and altitude degrees of freedom. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall optical path of the present invention; Figure 2 A schematic diagram of an observation receiving optical path A of the present invention; Figure 3 Schematic diagram of the signal transmission optical path B of the present invention; Figure 4 Schematic diagram of the near-infrared beacon receiving optical path C of the present invention; Figure 5 Schematic diagram of the receiving optical path D of the short-wave infrared beacon of the present invention; Figure 6 Schematic diagram of a single-photon signal receiving optical path E of the present invention; Figure 7 Schematic diagram of the receiving optical path F of the single-photon beacon of the present invention; Figure 8 Schematic diagram of the beacon emission optical path G of the present invention; Description of each component in the figure: 1. Main telescope; 2. Reflector 1; 3. Filter 1; 4. Coarse beacon receiving lens group; 5. Coarse beacon detector; 6. Reflector 2; 7. Reflector 5; 8. Compensation mirror group; 9. Fine tracking mirror 1; 10. Reflector 3; 11. Theodolite two-dimensional turntable; 12. Bidirectional angle reflection prism group; 13. Reflector 4; 14. Reflector 6; 15. Light trap; 16. Beam splitter 3; 17. Signal transmitting mirror group; 18. Signal light source; 19. Filter 2; 20. Fine beacon 1 receiving mirror group; 21. Precision beacon one detector; 22. Precision tracking mirror two; 23. Beam splitter one; 24. Filter three; 25. Precision beacon two receiving mirror group; 26. Precision beacon two detector; 27. Optical lifter; 28. Beam splitter two; 29. ​​Single-photon beacon receiving filter; 30. Single-photon beacon receiving mirror group; 31. Single-photon positioning detector; 32. Single-photon signal receiving filter; 33. Single-photon signal receiving mirror group; 34. Single-photon communication detector; 35. Beacon / signal laser; 36. Beacon / signal transmitting antenna. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] As attached Figure 1 As shown, the miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology of this embodiment includes the following optical components: Main telescope 1, reflector 1 2, filter 1 3, coarse beacon receiving lens group 4, coarse beacon detector 5, reflector 2 6, reflector 5 7, compensation lens group 8, fine tracking mirror 1 9, reflector 3 10, two-way angle reflection prism group 12, reflector 4 13, reflector 6 14, light trap 15, beam splitter 3 16, signal transmitting lens group 17, signal light source 18, filter 2 19, fine beacon 1 receiving lens group 20, fine beacon 1 detector 21, fine Tracking mirror 2 22, beam splitter 1 23, filter 3 24, precision beacon 2 receiving mirror group 25, precision beacon 2 detector 26, optical lifter 27, beam splitter 2 28, single photon beacon receiving filter 29, single photon beacon receiving mirror group 30, single photon positioning detector 31, single photon signal receiving filter 32, single photon signal receiving mirror group 33, single photon communication detector 34, beacon / signal laser 35, beacon / signal transmitting antenna 36; The above-mentioned optical components constitute 7 optical paths, namely, observation receiving optical path A, signal transmitting optical path B, near-infrared beacon receiving optical path C, short-wave infrared beacon receiving optical path D, single-photon signal receiving optical path E, single-photon beacon receiving optical path F, and beacon transmitting optical path G. These optical paths together complete the reception and transmission and detection of single-photon / non-single-photon beacon light / signal light, respectively, and together constitute a small laser communication terminal based on single-photon detection, which can be used for satellite-to-ground laser communication. Compared with traditional satellite-to-ground laser communication terminals, the antenna aperture is reduced to 20~30% of the original, the volume is only 20% of the traditional satellite-to-ground terminal, and the weight can be reduced by 80%, only 200~300kg; at the same time, miniaturization brings convenience to transportation and use. It can not only complete satellite-to-ground transmission, but also be compatible with ground point-to-point laser communication capabilities, and quickly realize satellite-to-ground and ground-to-ground communication conversion, which can greatly expand the scope of use of laser communication ground stations and can be widely used in air-to-ground, satellite-to-ground, deep space, and ground point-to-point laser communications.

[0019] like Figure 2As shown, the observation receiving optical path A in this embodiment is composed of a main telescope 1, a reflector 2, a filter 3, a coarse beacon receiving lens group 4, and a coarse beacon detector 5. After the external receiving light beam is collected and focused by the main telescope 1, it is reflected by the incident reflector 2, enters the filter 3 and the coarse beacon receiving lens group 4, and finally enters the coarse beacon detector 5 to complete the beacon light reception and positioning work. This optical path is used to measure the incident coarse beacon light; the electrical position feedback of the light spot on the coarse beacon detector 5 controls the target tracking of the theodolite two-dimensional turntable 11.

[0020] like Figure 3 As shown, the signal transmission optical path B in this embodiment is composed of a main telescope 1, a reflector 2 6, a reflector 5 7, a compensation mirror group 8, a fine tracking mirror 1 9, a reflector 3 10, a reflector 4 13, a reflector 6 14, a beam splitter 3 16, a signal transmission mirror group 17, and a signal light source 18. First, the signal light source 18 sends a signal light of a specified wavelength, which is shaped by the signal transmission mirror group 17, transmitted by the beam splitter 3 16, and then reflected by the reflector 6 14, the reflector 4 13, the reflector 3 10, and the fine tracking mirror 1 9, and then shaped and reduced by the main telescope 1 after passing through the compensation mirror group 8, the reflector 5 7, and the reflector 2 6, and then emitted to the target.

[0021] like Figure 4 As shown, the near-infrared beacon receiving optical path C in this embodiment is composed of a main telescope 1, a reflector 2 6, a reflector 5 7, a compensation mirror group 8, a precision tracking mirror 1 9, a reflector 3 10, a reflector 4 13, a reflector 6 14, a beam splitter 3 16, a filter 2 19, a precision beacon 1 receiving mirror group 20, and a precision beacon 1 detector 21. After the external beacon light is received and focused by the main telescope 1, it passes through the reflector 5 7, the precision tracking mirror 1 9, the reflector 3 10, the reflector 4 13, the reflector 6 14, and the beam splitter 3 16 and is incident on the filter 2 19 and the precision beacon 1 receiving mirror group 20, and is finally imaged on the precision beacon 1 detector 21. The optical path uses the beacon light spot information on the precision beacon 1 detector 21 to realize closed-loop tracking of the precision tracking mirror 1 9.

[0022] like Figure 5As shown, the short-wave infrared beacon receiving optical path D in this embodiment is composed of the main telescope 1, the second reflector 6, the fifth reflector 7, the compensation mirror group 8, the fine tracking mirror 1 9, the third reflector 10, the fourth reflector 13, the sixth reflector 14, the fine tracking mirror 2 2, the beam splitter 1 23, the filter 3 24, the fine beacon 2 receiving mirror group 25, and the fine beacon 2 detector 26. After the external short-wave infrared beacon light is received and focused by the main telescope 1, it passes through the fifth reflector 7, the compensation mirror group 8, the fine tracking mirror 1 9, the third reflector 10, the fourth reflector 13, the sixth reflector 14, the fine tracking mirror 2 2, and the beam splitter 1 23 and is incident on the filter 3 24 and the fine beacon 2 receiving mirror group 25, and is finally imaged on the fine beacon 2 detector 26. The optical path uses the beacon light spot information on the fine beacon 2 detector 26 to realize closed-loop tracking of the fine tracking mirror 2 22.

[0023] like Figure 6 As shown, the single-photon signal receiving optical path E in this embodiment is composed of a main telescope 1, a second reflector 6, a fifth reflector 7, a compensation mirror group 8, a precision tracking mirror 1 9, a third reflector 10, a fourth reflector 13, a sixth reflector 14, a precision tracking mirror 2 22, a beam splitter 1 23, an optical riser 27, a beam splitter 2 28, a single-photon signal receiving filter 32, a single-photon signal receiving mirror group 33, and a single-photon communication detector 34. After the external communication light is received and beam-contracted by the main telescope 1, After passing through reflector five 7, compensation mirror group 8, precision tracking mirror one 9, reflector three 10, reflector four 13, reflector six 14, precision tracking mirror two 22, and beam splitter one 23, it is incident on the optical lifter 27, reflected by the incident beam splitter two 28, and enters the single-photon signal receiving filter 32 and the single-photon signal receiving mirror group 33, and is finally focused on the incident single-photon communication detector 34, and the single-photon communication detector 34 is used to realize the reception of the communication signal by the received signal light.

[0024] like Figure 7 As shown, the single-photon beacon receiving optical path F in this embodiment is composed of a main telescope 1, a second reflector 6, a fifth reflector 7, a compensation mirror group 8, a precision tracking mirror 1 9, a third reflector 10, a fourth reflector 13, a sixth reflector 14, a precision tracking mirror 2 22, a beam splitter 1 23, an optical riser 27, a beam splitter 28, a single-photon beacon receiving filter 29, a single-photon beacon receiving mirror group 30, and a single-photon positioning detector 31. The external communication light is received by the main telescope 1 and then beam-contracted. After passing through reflector five 7, compensation mirror group 8, precision tracking mirror one 9, reflector three 10, reflector four 13, reflector six 14, precision tracking mirror two 22, and beam splitter one 23, it is incident on the optical lifter 27, and after being reflected by beam splitter two 28, it is incident on the single-photon beacon receiving filter 29 and single-photon beacon receiving mirror group 30, and is finally imaged on the single-photon positioning detector 31. This optical path uses the single-photon positioning information of the single-photon positioning detector 31 to perform closed-loop tracking on the precision tracking mirror two 22.

[0025] like Figure 8 As shown, the beacon transmission optical path G in this embodiment is composed of a beacon / signal laser 35 and a beacon / signal transmitting antenna 36. The beacon light that meets the wavelength is emitted by the beacon laser 35 and is shaped and the beam divergence angle is compressed by the beacon / signal transmitting antenna 36, ​​and is pointed to the target and sent along the two-dimensional turntable 11 of the theodolite.

[0026] In this embodiment, the main telescope 1, reflector 1 2, filter 1 3, coarse beacon receiving lens group 4, coarse beacon detector 5, reflector 2 6, reflector 5 7, compensation mirror group 8, fine tracking mirror 1 9, reflector 3 10, bidirectional angle reflection prism group 12, reflector 4 13, beacon / signal laser 35, and beacon / signal transmitting antenna 36 are placed on the theodolite two-dimensional turntable 11; the target tracking of the theodolite two-dimensional turntable 11 is controlled by electrical position feedback of the light spot on the coarse beacon detector 5.

[0027] The main telescope 1 in this embodiment adopts a Cassegrain telescope with a receiving field of view as large as possible, preferably 4-8 mrad, and is matched with a compensation mirror group 8 to realize parallel light transmission at the Kuder optical path terminal.

[0028] In this embodiment, the two-way corner reflection prism set 12 is inserted into the optical path through a servo mechanism, and the aperture of the two-way corner reflection prism set should be larger than the internal light beam size, preferably 2 inches.

[0029] In this embodiment, an adaptive optical component is added between the reflector four 13 and the reflector six 14 to achieve time domain and spatial domain compensation for atmospheric influences through wavefront detection and wavefront correction. Considering that the aperture is significantly reduced, the number of corresponding adaptive optical component units can also be reduced to 32 to 64 units.

[0030] The splitting ratio of the beam splitter 23 in this embodiment needs to be divided according to the sensitivity characteristics of the precision beacon detector 26, the single photon positioning detector 31, and the single photon communication detector 34. That is, the splitting ratio of the beam splitter 23 is ,in is the sensitivity of the precision beacon second detector 26, in dBm; is the sensitivity of the single photon localization detector 31, in dBm; is the sensitivity of the single photon communication detector 34, in dBm. In this embodiment, the sensitivity of the precision beacon second detector 26 is -72.5 dBm (generally -72 to -73 dBm): the sensitivity of the single photon positioning detector 31 and the single photon communication detector 34 are both -75 dBm, so in the design of this embodiment, the splitting ratio of the beam splitter is Should meet: .

Claims

1. A miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology, comprising the following optical components: Main telescope (1), reflector 1 (2), filter 1 (3), coarse beacon receiving lens group (4), coarse beacon detector (5), reflector 2 (6), reflector 5 (7), compensation lens group (8), fine tracking lens 1 (9), reflector 3 (10), two-way angle reflection prism group (12), reflector 4 (13), reflector 6 (14), light trap (15), beam splitter 3 (16), signal transmitting lens group (17), signal light source (18), filter 2 (19), fine beacon 1 receiving lens group (20), fine beacon 1 detector (21) , precision tracking mirror 2 (22), beam splitter 1 (23), filter 3 (24), precision beacon 2 receiving mirror group (25), precision beacon 2 detector (26), optical lifter (27), beam splitter 2 (28), single-photon beacon receiving filter (29), single-photon beacon receiving mirror group (30), single-photon positioning detector (31), single-photon signal receiving filter (32), single-photon signal receiving mirror group (33), single-photon communication detector (34), beacon / signal laser (35), beacon / signal transmitting antenna (36); characterized in that, The above optical components constitute the observation receiving optical path A, the signal transmitting optical path B, the near-infrared beacon receiving optical path C, the short-wave infrared beacon receiving optical path D, the single-photon signal receiving optical path E, the single-photon beacon receiving optical path F, and the beacon transmitting optical path G, wherein: The observation receiving optical path A is composed of a main telescope (1), a reflector 1 (2), a filter 1 (3), a coarse beacon receiving lens group (4), and a coarse beacon detector (5). After the external receiving light beam is collected and reduced by the main telescope (1), it is reflected by the incident reflector 1 (2), enters the filter 1 (3) and the coarse beacon receiving lens group (4), and finally enters the coarse beacon detector (5), completing the beacon light reception and positioning work. The optical path is used to measure the incident coarse beacon light. The signal transmission optical path B is composed of a main telescope (1), a reflector 2 (6), a reflector 5 (7), a compensation mirror group (8), a precision tracking mirror 1 (9), a reflector 3 (10), a reflector 4 (13), a reflector 6 (14), a beam splitter 3 (16), a signal transmission mirror group (17), and a signal light source (18). First, the signal light source (18) transmits a signal light of a specified wavelength, which is shaped by the signal transmission mirror group (17), transmitted by the beam splitter 3 (16), reflected by the reflector 6 (14), the reflector 4 (13), the reflector 3 (10), and the precision tracking mirror 1 (9), and then shaped and reduced by the compensation mirror group (8), the reflector 5 (7), and the reflector 2 (6) before being transmitted to the target by the main telescope (1). The near-infrared beacon receiving optical path C is composed of a main telescope (1), a reflector 2 (6), a reflector 5 (7), a compensation mirror group (8), a precision tracking mirror 1 (9), a reflector 3 (10), a reflector 4 (13), a reflector 6 (14), a beam splitter 3 (16), a filter 2 (19), a precision beacon 1 receiving mirror group (20), and a precision beacon 1 detector (21). After receiving and converging the external beacon light through the main telescope (1), the external beacon light passes through the reflector 5 (7), the precision tracking mirror 1 (9), the reflector 3 (10), the reflector 4 (13), the reflector 6 (14), and the beam splitter 3 (16), and is incident on the filter 2 (19) and the precision beacon 1 receiving mirror group (20), and finally forms an image on the precision beacon 1 detector (21). The optical path uses the beacon light spot information on the precision beacon 1 detector (21) to realize closed-loop tracking of the precision tracking mirror 1 (9). The short-wave infrared beacon receiving optical path D is composed of a main telescope (1), a reflector 2 (6), a reflector 5 (7), a compensation mirror group (8), a precision tracking mirror 1 (9), a reflector 3 (10), a reflector 4 (13), a reflector 6 (14), a precision tracking mirror 2 (22), a beam splitter 1 (23), a filter 3 (24), a precision beacon 2 receiving mirror group (25), and a precision beacon 2 detector (26). The external short-wave infrared beacon light is received by the main telescope (1) and then beam-contracted. , passing through reflector five (7), compensation mirror group (8), precision tracking mirror one (9), reflector three (10), reflector four (13), reflector six (14), precision tracking mirror two (22), beam splitter one (23), incident on filter three (24), precision beacon two receiving mirror group (25), and finally imaged on precision beacon two detector (26). This optical path uses the beacon light spot information on the precision beacon two detector (26) to achieve closed-loop tracking of precision tracking mirror two (22); The single-photon signal receiving optical path E is composed of a main telescope (1), a reflector 2 (6), a reflector 5 (7), a compensation mirror group (8), a precision tracking mirror 1 (9), a reflector 3 (10), a reflector 4 (13), a reflector 6 (14), a precision tracking mirror 2 (22), a beam splitter 1 (23), an optical riser (27), a beam splitter 2 (28), a single-photon signal receiving filter (32), a single-photon signal receiving mirror group (33), and a single-photon communication detector (34). The external communication light is received by the main telescope (1) and then beam-contracted. After passing through the reflector five (7), the compensation mirror group (8), the precision tracking mirror one (9), the reflector three (10), the reflector four (13), the reflector six (14), the precision tracking mirror two (22), and the beam splitter one (23), the light is incident on the optical lifter (27), and after being reflected by the incident beam splitter two (28), it is incident on the single-photon signal receiving filter (32), the single-photon signal receiving mirror group (33), and finally focused on the incident single-photon communication detector (34), and the single-photon communication detector (34) is used to realize the reception of the communication signal by receiving the received signal light; The single-photon beacon receiving optical path F is composed of a main telescope (1), a reflector 2 (6), a reflector 5 (7), a compensation mirror group (8), a precision tracking mirror 1 (9), a reflector 3 (10), a reflector 4 (13), a reflector 6 (14), a precision tracking mirror 2 (22), a beam splitter 1 (23), an optical lifter (27), a beam splitter 2 (28), a single-photon beacon receiving filter (29), a single-photon beacon receiving mirror group (30), and a single-photon positioning detector (31). The external communication light is received by the main telescope (1) and beam-contracted, and then passes through the reflector. Five (7), compensation mirror group (8), precision tracking mirror one (9), reflector three (10), reflector four (13), reflector six (14), precision tracking mirror two (22), beam splitter one (23) are incident on the optical lifter (27), and after being reflected by beam splitter two (28), they are incident on the single-photon beacon receiving filter (29), the single-photon beacon receiving mirror group (30), and finally imaged on the single-photon positioning detector (31). The optical path uses the single-photon positioning information on the single-photon positioning detector (31) to perform closed-loop tracking on the precision tracking mirror two (22); The beacon transmission optical path G is composed of a beacon / signal laser (35) and a beacon / signal transmission antenna (36). Beacon light that meets the wavelength is emitted by the beacon laser (35) and is shaped and beam divergence angle compressed by the beacon / signal transmission antenna (36). It is then directed toward the target and transmitted along the theodolite two-dimensional turntable (11).

2. According to claim 1, a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology is characterized in that: The main telescope (1), reflector 1 (2), filter 1 (3), coarse beacon receiving lens group (4), coarse beacon detector (5), reflector 2 (6), reflector 5 (7), compensation mirror group (8), fine tracking mirror 1 (9), reflector 3 (10), bidirectional angle reflection prism group (12), reflector 4 (13), beacon / signal laser (35), and beacon / signal transmitting antenna (36) are placed on a two-dimensional turntable (11) of the theodolite; and target tracking of the two-dimensional turntable (11) of the theodolite is controlled by feedback of the electrical position of the light spot on the coarse beacon detector (5).

3. According to claim 1, a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology is characterized in that: The main telescope (1) is a Cassegrain telescope.

4. According to claim 1, a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology is characterized in that: The two-way corner reflection prism set (12) is inserted into the optical path through a servo mechanism, and the diameter of the two-way corner reflection prism set (12) should be greater than 2 inches.

5. According to claim 1, a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology is characterized in that: An adaptive optical component is added between the reflector four (13) and the reflector six (14), and the adaptive optical component has 32 to 64 units.

6. According to claim 1, a miniaturized satellite-to-ground laser communication terminal based on single-photon detection technology is characterized in that: The splitting ratio of the beam splitter 1 (23) needs to be based on the sensitivity characteristics of the precision beacon 2 detector (26), the single photon positioning detector (31), and the single photon communication detector (34) to divide the light intensity, that is, the splitting ratio of the beam splitter 1 (23) ,in is the sensitivity of the precision beacon second detector (26), in dBm; is the sensitivity of the single photon localization detector (31), in dBm; is the sensitivity of the single-photon communication detector (34), in dBm.

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