A space laser communication device and control method thereof

Abstract

The present application belongs to the field of space laser communication technology, and specifically discloses a space laser communication device and its control method. The device includes: a focusing lens, a microlens, a multi-core optical fiber, and a calculation module; the multi-core optical fiber includes a central optical fiber and a plurality of non-central optical fibers distributed around the central optical fiber, and the end face of each non-central optical fiber is coplanar with the end face of the central optical fiber, and the distance between each non-central optical fiber and the central optical fiber is equal; the central axes of the focusing lens, the microlens, and the central optical fiber are collinear; the size of the microlens is smaller than that of the focusing lens; the focusing lens is used to focus the incident light; the microlens is used to refocus the light beam after being focused by the focusing lens and transmit it to the multi-core optical fiber; the calculation module is used to determine the incident angle of the incident light based on the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber. Through this application, the angular measurement range and accuracy of the device can be effectively improved, and the optical path system is simple.

Description

Technical Field

[0001] The present application belongs to the field of space laser communication technology, and more specifically, relates to a space laser communication device and a control method thereof. Background Art

[0002] Free-space optical communication (FSO) technology uses lasers as information carriers to achieve wireless communications in free space. It offers advantages such as high security, fast communication rates, high transmission efficiency, flexible wavelength selection, and large information capacity. Given its advantages such as small terminal system size, light weight, low power consumption, easy installation, and high flexibility, FSO technology has significant strategic demand and application value in both military and civilian fields.

[0003] Traditional space laser communication devices primarily consist of a laser, a pan-tilt head (PTZ), a CCD camera, a fast reflector, and a four-quadrant detector. The beam capture and alignment process is performed in two stages: coarse capture and fine alignment. However, a major drawback of this design is that when measuring the incident angle of the beam, a portion of the light must be split onto a four-quadrant detector or other photoelectric detection device. Directly estimating the spot offset based on the area of ​​the spot falling on each of the four quadrants results in significant errors, resulting in low angular measurement accuracy and low lateral angle range. Summary of the Invention

[0004] In view of the defects of the existing technology, the present application aims to solve the problem that the angle measurement accuracy and side angle range of the existing space laser communication devices are not high.

[0005] To achieve the above objectives, in a first aspect, the present application provides a space laser communication device, comprising:

[0006] focusing lenses, microlenses, multi-core optical fibers, and computing modules;

[0007] The multi-core optical fiber includes a central optical fiber and a plurality of non-central optical fibers distributed around the central optical fiber, and the end face of each non-central optical fiber is coplanar with the end face of the central optical fiber, and the distance between each non-central optical fiber and the central optical fiber is equal;

[0008] The central axes of the focusing lens, the microlens, and the central optical fiber are collinear; the size of the microlens is smaller than that of the focusing lens;

[0009] The focusing lens is used to focus the incident light;

[0010] The microlens is used to refocus the light beam focused by the focusing lens and transmit it to the multi-core optical fiber;

[0011] The calculation module is used to determine the incident angle of the incident light based on radial offsets of light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber.

[0012] According to a space laser communication device provided by this application, the computing module is specifically used for:

[0013] In a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in each of the non-parallel radial directions, a first offset of each of the radial offsets of the light spots relative to the abscissa axis of the plane rectangular coordinate system and a second offset of each of the radial offsets of the light spots relative to the ordinate axis of the plane rectangular coordinate system are calculated; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin;

[0014] determining a first incident angle of the incident light relative to the abscissa axis based on a sum of the first offsets and a target focal length;

[0015] determining a second incident angle of the incident light relative to the longitudinal axis based on a sum of the second offsets and the target focal length;

[0016] The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; and the incident angle includes the first incident angle and the second incident angle.

[0017] According to a space laser communication device provided by this application, the computing module is specifically used for:

[0018] For any light spot radial offset among the light spot radial offsets, performing a product operation on the light spot radial offset and a target cosine value to obtain a first offset of the light spot radial offset relative to the abscissa axis;

[0019] Performing a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the vertical coordinate axis;

[0020] The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any one of the light spot radial offsets and the total vector direction corresponding to each of the non-parallel radial directions.

[0021] A space laser communication device provided by the present application further includes: a light splitting module;

[0022] The light splitting module includes a detection beam output end; the detection beam output end is connected to the calculation module;

[0023] The optical splitting module is used to split the communication beam and the detection beam output by the multi-core optical fiber, and output the detection beam through the detection beam output end; the communication beam is the beam coupled by the incident light into the central optical fiber; the detection beam is the beam coupled by the incident light into the non-central optical fiber;

[0024] The calculation module is further configured to determine radial offsets of light spots in multiple non-parallel radial directions within the end face of the multi-core optical fiber based on optical power information of the detection beam.

[0025] A space laser communication device provided by the present application further includes: a modulation and demodulation module;

[0026] The optical splitting module includes a communication beam output end for outputting the communication beam; the communication beam output end is connected to the modulation and demodulation module;

[0027] The modulation and demodulation module is used to modulate the local communication laser of the device when the device serves as a signal transmitting end, and send the modulated signal to the communication beam output end, so as to send the modulated signal out through the central optical fiber;

[0028] The modulation and demodulation module is further configured to demodulate the communication light beam outputted from the communication light beam output end when the device serves as a signal receiving end.

[0029] According to a space laser communication device provided by the present application, the radius of the microlens is greater than the radius of the central optical fiber and smaller than the distance between the central optical fiber and the non-central optical fiber.

[0030] In a second aspect, the present application further provides a control method for a space laser communication device as described above, the method comprising:

[0031] Focusing the incident light using the focusing lens;

[0032] Using the microlens to refocus the light beam focused by the focusing lens and transmit it to the multi-core optical fiber;

[0033] The calculation module determines the incident angle of the incident light based on radial offsets of light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber.

[0034] According to a control method for a space laser communication device provided by the present application, the calculation module determines the incident angle of the incident light based on the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber, including:

[0035] The calculation module calculates, based on the radial offsets of the light spots in the non-parallel radial directions, a first offset of each radial offset of the light spots relative to the abscissa axis of the plane rectangular coordinate system, and a second offset of each radial offset of the light spots relative to the ordinate axis of the plane rectangular coordinate system in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin;

[0036] The calculation module determines a first incident angle of the incident light relative to the abscissa axis based on a sum of the first offsets and a target focal length;

[0037] The calculation module determines a second incident angle of the incident light relative to the longitudinal axis based on a sum of the second offsets and the target focal length;

[0038] The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; and the incident angle includes the first incident angle and the second incident angle.

[0039] According to a control method for a space laser communication device provided by the present application, the calculation module calculates, in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in the non-parallel radial directions, a first offset of each of the radial offsets of the light spots relative to the abscissa axis of the plane rectangular coordinate system, and a second offset of each of the radial offsets of the light spots relative to the ordinate axis of the plane rectangular coordinate system, including:

[0040] For any one of the light spot radial offsets, the calculation module performs a product operation on the light spot radial offset and a target cosine value to obtain a first offset of the light spot radial offset relative to the abscissa axis;

[0041] The calculation module performs a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the vertical coordinate axis;

[0042] The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any one of the light spot radial offsets and the total vector direction corresponding to each of the non-parallel radial directions.

[0043] According to a control method for a space laser communication device provided by the present application, the device further includes a spectrometer module; the spectrometer module includes a detection beam output end; the detection beam output end is connected to the calculation module; the method further includes:

[0044] The optical splitting module splits the communication beam and the detection beam output by the multi-core optical fiber, and outputs the detection beam through the detection beam output end; the communication beam is the beam coupled by the incident light into the central optical fiber; the detection beam is the beam coupled by the incident light into the non-central optical fiber;

[0045] The calculation module determines radial offsets of light spots in multiple non-parallel radial directions within the end face of the multi-core optical fiber based on optical power information of the detection beam.

[0046] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0047] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0048] The space laser communication device and control method provided by the present application introduce a microlens structure. The microlens refocuses the laser beam after being focused by the focusing lens, so that the incident laser is efficiently coupled into the central optical fiber. At the same time, the light beam passing through the non-central optical fiber can be used to measure the radial offset of the light spot in multiple non-parallel radial directions within the end face of the multi-core optical fiber, and calculate the deviation angle of the incident light beam. In addition, all the core end faces of the multi-core optical fiber are in the same plane, and no changes in the optical fiber structure are required. The angular measurement range and accuracy can be effectively improved. The optical path system is simple, which is conducive to improving the communication performance of the device and greatly reduces the difficulty and cost of optical fiber processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is one of the structural diagrams of the space laser communication device provided by this application;

[0050] Figure 2 This is a schematic diagram of a light beam passing through a microlens and incident on a multi-core optical fiber in a space laser communication device provided by the present application;

[0051] Figure 3 This is the second structural diagram of the space laser communication device provided by this application;

[0052] Figure 4 This is a schematic diagram of the structure of the microlens-based spatial laser angle measurement and communication integrated system provided by the present application;

[0053] Figure 5 It is a flow chart of the control method of the space laser communication device provided in this application. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0055] The terms "first" and "second" in this specification and claims are used to distinguish different objects rather than to describe a specific order of objects. For example, "first response message" and "second response message" are used to distinguish different response messages rather than to describe a specific order of response messages.

[0056] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0057] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0058] Prior art has proposed a multi-core optical fiber device with a stepped structure for integrating angle measurement and communication functions in space laser communications. However, the protruding central optical fiber core structure in this approach can block and lose the incident light beam, reducing angle measurement accuracy and the range of lateral angles. Furthermore, this structure is difficult to manufacture and is costly.

[0059] To this end, in order to solve the above-mentioned technical defects existing in the prior art, the present application provides a space laser communication device and a control method thereof.

[0060] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0061] Figure 1 This is one of the structural diagrams of the space laser communication device provided by this application, such as Figure 1 As shown, the device includes:

[0062] Focusing lens 1, micro lens 2, multi-core optical fiber 3 and computing module 4;

[0063] The multi-core optical fiber 3 includes a central optical fiber 31 and a plurality of non-central optical fibers 32 distributed around the central optical fiber 31, and the end face of each non-central optical fiber 32 is coplanar with the end face of the central optical fiber 31, and the spacing between each non-central optical fiber 32 and the central optical fiber 31 is equal;

[0064] The central axes of the focusing lens 1, the micro lens 2, and the central optical fiber 31 are collinear; the size of the micro lens 2 is smaller than that of the focusing lens 1;

[0065] The focusing lens 1 is used to focus the incident light;

[0066] The micro lens 2 is used to refocus the light beam after being focused by the focusing lens and transmit it to the multi-core optical fiber 3;

[0067] The calculation module 4 is used to determine the incident angle of the incident light based on the radial offsets of the light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber 3 .

[0068] It can be understood that the central optical fiber described in the embodiments of the present application refers to the optical fiber located on the central axis of the multi-core optical fiber, and the non-central optical fiber is the optical fiber distributed around the central optical fiber.

[0069] Specifically, the radial offset of the light spot described in the embodiments of this application refers to the offset of the light spot of the incident light beam in multiple non-parallel radial directions within the end face of a multi-core optical fiber relative to the center point of the end face. This can be obtained by detecting and analyzing the detection beam output by the non-center optical fiber using a calculation module.

[0070] In the embodiments of the present application, a focusing lens is used to initially focus the parallel light beam incident on the device, converging the incident light and transmitting it to the microlens. The incident light beam passes through the microlens, focusing more light and coupling it into the central fiber core. The propagation mode of the incident light that has not passed through the microlens remains unchanged, manifesting as a larger light spot on the end face of the multi-core fiber. This allows the optical power to be detected in non-central fiber cores, and the current light spot position can be determined based on the correlation between the optical powers in different fiber cores.

[0071] The microlens is smaller than the focusing lens. It is fixedly positioned between the focusing lens and the multi-core fiber. The distance from the center of the microlens to the end face of the center fiber is equal to the focal length of the lens. Furthermore, the central axes of the focusing lens, microlens, and center fiber of the multi-core fiber are collinear.

[0072] Figure 2 This is a schematic diagram of a light beam passing through a microlens and incident on a multi-core optical fiber in a space laser communication device provided by the present application. Figure 2 As shown in the figure, the radius of the microlens is larger than the radius of the central fiber and smaller than the distance between the central fiber and the non-central fiber. This ensures that the microlens can effectively focus on the light spot in front of the central fiber without affecting the light transmission of other fiber cores, so that the incident laser can be coupled into the central fiber with higher efficiency, which is beneficial to improving the communication performance of the device.

[0073] Continue to refer to Figure 2, a multi-core optical fiber, includes a central optical fiber and N non-central optical fibers evenly arranged around the central optical fiber. The spacing between each non-central optical fiber and the central optical fiber is equal, and is used to receive the focused incident light. The core end faces of the non-central optical fiber and the central optical fiber are both on the same plane. The incident light beam is focused into the core of the central optical fiber through a microlens, which can couple into higher optical power for communication, and can form a communication beam spot on the end face of the multi-core optical fiber; the light beam transmission that has not passed through the microlens is not affected, and its size on the end face of the multi-core optical fiber is larger, which can cover the cores of multiple non-central optical fibers to form a detection beam spot for angle measurement.

[0074] It should be noted that the detection beam spot at the end face of the multi-core optical fiber covers at least the cores of two non-central optical fibers. When the incident light is aligned with the incident direction, the spot is focused into the central optical fiber.

[0075] It should also be noted that in the embodiment of the present application, the incident light beam can be a Gaussian beam, and the beam waist position is at the end face of the collimator. When the lens group is determined, the beam waist radius of the Gaussian beam satisfies the formula:

[0076]

[0077] The waist position satisfies the formula:

[0078]

[0079] Where F represents the focal length of the focusing lens, ω0 represents the waist radius of the Gaussian beam that has not passed through the focusing lens, l represents the distance from the waist position of the Gaussian beam that has not passed through the focusing lens to the focusing lens, and l′ represents the distance from the waist position of the Gaussian beam that has only passed through the focusing lens to the focusing lens.

[0080] At long distances, i.e., l>>F, the incident beam passes through the focusing lens and only passes through the Gaussian beam waist radius of the focusing lens. l'≈F, at this time l'>>F', where F' represents the focal length of the microlens. The incident light beam passes through the microlens, and the Gaussian beam waist radius after passing through the focusing lens and microlens is The distance l″≈F′ between the waist position of the Gaussian beam after passing through the focusing lens and the microlens and the microlens.

[0081] In a specific embodiment of the present application, l = 50F, a focusing lens with a focal length of 50mm is used, the distance between the microlens and the focusing lens is 50mm, the focal length of the microlens is 252μm, and the distance between the multi-core fiber end face and the microlens is 252μm. The incident beam waist radius is set to 1.43mm, and the incident light wavelength is 1550nm. The calculation shows that the communication beam spot radius at the fiber end face after the beam passes through the microlens is 6.5μm, and the detection beam spot radius at the fiber end face without passing through the microlens is 28.6μm.

[0082] In the examples of this application, simulations using the optical simulation software ZEMAX verified that the multi-core fiber used a seven-core fiber with a core spacing of 41.5μm, a microlens diameter of 80μm, and a focal length of 252μm. The spot diameter of the beam passing through the microlens on the end face was 8.2μm, with a coupling efficiency of 96.6%. The spot diameter of the beam not passing through the microlens on the end face was 44μm, with a detection range of ±0.02°-0.07°.

[0083] The system uses a 7-core fiber with a core pitch of 41.5μm, a microlens diameter of 60μm, and a focal length of 252μm. The spot diameter of the beam passing through the microlens on the end face is 7.5μm, with a coupling efficiency of 96.8%. The spot diameter of the beam not passing through the microlens on the end face is 45μm, and the detection range is ±0.01° to 0.07°.

[0084] Furthermore, in an embodiment of the present application, a calculation module is used to detect the incident angle of the incident laser beam. Specifically, it can perform optical analysis based on the radial offset of the light spot in multiple non-parallel radial directions within the end face of the multi-core optical fiber and the focal length of each lens to calculate the incident angle of the incident light.

[0085] The spatial laser communication device of the embodiment of the present application introduces a microlens structure. The microlens refocuses the laser beam after being focused by the focusing lens, so that the incident laser is efficiently coupled into the central optical fiber. At the same time, the light beam passing through the non-central optical fiber can be used to measure the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber, and calculate the deviation angle of the incident light beam. In addition, all the core end faces of the multi-core optical fiber are in the same plane, and no changes in the optical fiber structure are required. The angular measurement range and accuracy can be effectively improved. The optical path system is simple, which is conducive to improving the communication performance of the device and greatly reduces the difficulty and cost of optical fiber processing.

[0086] Figure 3 This is the second structural diagram of the space laser communication device provided by this application, such as Figure 3 As shown, in the embodiment of the present application, the device further includes: a light splitting module 5;

[0087] The light splitting module 5 includes a detection beam output end 51; the detection beam output end 51 is connected to the calculation module 4;

[0088] The optical splitter module 5 is used to split the communication beam and the detection beam output by the multi-core optical fiber 3, and output the detection beam through the detection beam output end 51; the communication beam is the beam of incident light coupled into the central optical fiber; the detection beam is the beam of incident light coupled into the non-central optical fiber;

[0089] The calculation module 4 is further configured to determine radial offsets of the light spots in multiple non-parallel radial directions within the end face of the multi-core optical fiber 3 based on the optical power information of the detection light beam.

[0090] Specifically, in an embodiment of the present application, the optical splitter module is used to spatially demultiplex the cores in the multi-core optical fiber, so that each core is fanned out in N+1 optical fibers, thereby distinguishing the communication beam and the detection beam output by the multi-core optical fiber, and outputting the detection beam through the detection beam output end. The communication beam and the detection beam are the incident light coupled into the central optical fiber and the non-central optical fiber, respectively. It can be understood that the detection beam output end is connected to each non-central optical fiber for outputting the detection beam coupled to each non-central optical fiber.

[0091] In an embodiment of the present application, the calculation module may include N detectors and a deviation angle calculation module, each detector being connected to each non-center optical fiber respectively to detect the detection beam output by the non-center optical fiber connected thereto.

[0092] Similarly, for optical fiber bundle structures (symmetrical or asymmetric structures) that are fixed by mechanical means, when the system can ensure that part of the optical fiber can detect power, placing a microlens of appropriate size in front of the communication optical fiber can play an integrated role in communication angle measurement in the field of space laser communication.

[0093] In an embodiment of the present application, the output end of the detection beam is connected to the calculation module, and the optical power of the detection beam output by each non-central optical fiber is detected by each detector, and the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber is calculated based on the optical power information of the detection beam through the deviation angle calculation module.

[0094] Specifically, when the incident angle of the incident light changes, the coupling efficiency and propagation path of the incident light in each fiber of the multi-core fiber will change, resulting in a change in the light intensity output by each fiber. Through the various detectors in the calculation module, the light intensity Pi of the light beam coupled to any core in the multi-core fiber can be detected. The correlation coefficient ki is set, where Pm and Pn represent the optical powers at two power points in the radial direction, respectively. The offset can be obtained in real time through proportional mapping, so that the incident angle of the incident light can be determined by the radial offset vectors of the light spots in multiple non-parallel radial directions.

[0095] It should be noted that when N is an even number, the power point is located at the center point of the non-center fiber on the end face of the multi-core fiber, and its optical power can be obtained by detecting the optical power in the non-center fiber through a detector.

[0096] When N is an odd number, the power point includes the non-central fiber center point on the multi-core fiber end face and a virtual point symmetrical to the center point about the multi-core fiber end face center point O. The optical power at the virtual point can be calculated based on the Gaussian distribution characteristics of the incident light spot on the multi-core fiber end face by using the optical power of any three non-central fiber center points. Optionally, the optical power of the non-central fiber center point is obtained by detecting the optical power in the non-central fiber using a detector.

[0097] It can be obtained that the radial offset of the light spot in the i-th radial direction is:

[0098]

[0099] Among them, k i represents the power coefficient in the i-th radial direction; k i_max represents the maximum value of the power coefficient of the incident light in the i-th radial direction; S i_max It represents the maximum offset of the center point of the incident light spot relative to the center point O in the i-th radial direction.

[0100] According to the above formula, the radial offsets of the light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber can be calculated.

[0101] The device of the embodiment of the present application introduces a splitter module to split the communication beam and the detection beam output by the multi-core optical fiber, and transmits the detection beam to the calculation module for detection and calculation, thereby obtaining the radial offset of the light spot in multiple non-parallel radial directions within the end face of the multi-core optical fiber, providing reliable data for the subsequent accurate measurement of the incident angle of the incident light beam, and improving the angular measurement accuracy of the device.

[0102] Based on the content of the above embodiment, as an optional embodiment, the calculation module 4 is specifically configured to:

[0103] In a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in each non-parallel radial direction, a first offset of each radial offset of the light spots relative to the abscissa axis (hereinafter referred to as the x-axis) of the plane rectangular coordinate system and a second offset of each radial offset of the light spots relative to the ordinate axis (hereinafter referred to as the y-axis) of the plane rectangular coordinate system are calculated; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin;

[0104] determining a first incident angle of the incident light relative to the x-axis based on a sum of the first offsets and the target focal length;

[0105] determining a second incident angle of the incident light relative to the y-axis based on a sum of the second offsets and the target focal length;

[0106] The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; the incident angle includes a first incident angle and a second incident angle.

[0107] Specifically, in an embodiment of the present application, a plane rectangular coordinate system is established with the center point O of the multi-core optical fiber end face as the origin, and the position of the center of the incident light spot on the multi-core optical fiber end face can be expressed by the offset of the center of the incident light spot relative to point O on the rectangular coordinate system.

[0108] In an embodiment of the present application, in the plane rectangular coordinate system established above, the radial offsets of the light spots in each non-parallel radial direction are decomposed to calculate the first offset of each radial offset of the light spot relative to the x-axis and the second offset of each radial offset of the light spot relative to the y-axis.

[0109] Based on the content of the above embodiment, as an optional embodiment, the calculation module is specifically configured to:

[0110] For any light spot radial offset among the light spot radial offsets, a product operation is performed on the light spot radial offset and the target cosine value to obtain a first offset of the light spot radial offset relative to the x-axis;

[0111] Perform a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the y-axis;

[0112] The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any light spot radial offset and the total vector direction corresponding to each non-parallel radial direction.

[0113] Specifically, in an embodiment of the present application, for any one of the radial offsets of the light spot in multiple non-parallel radial directions within the end face of the multi-core optical fiber, a product operation is performed by multiplying the radial offset of the light spot with the target cosine value to obtain a first offset of the radial offset of the light spot relative to the x-axis. This process can be specifically expressed as follows:

[0114]

[0115] Where Δx i It represents the first offset of the radial offset of the light spot in the i-th vector direction relative to the x-axis, S i Indicates the radial offset of the light spot in the i-th vector direction, represents the total vector direction corresponding to each non-parallel radial direction, Represents the direction of the i-th vector.

[0116] In the embodiment of the present application, a second offset of the radial offset of the light spot relative to the y-axis can be obtained by multiplying the radial offset of the light spot by the target sine value. The process can be specifically expressed as follows:

[0117]

[0118] Where Δy i It represents the second offset of the radial offset of the light spot in the i-th vector direction relative to the y-axis.

[0119] The device of the embodiment of the present application, through a preset calculation program, enables the calculation module to calculate the components of the radial offset of the light spot in any non-parallel radial direction within the end face of the multi-core optical fiber relative to each coordinate axis in the plane coordinate system, thereby facilitating the subsequent optical analysis and calculation of the incident angle of the incident light, and is conducive to improving the accuracy of the angle measurement calculation.

[0120] Furthermore, the sum of the first offsets and the sum of the second offsets can be calculated, wherein the sum of the first offsets can represent the offset of the center of the light spot relative to the x-axis in the plane rectangular coordinate system, and the sum of the second offsets can represent the offset of the center of the light spot relative to the y-axis in the plane rectangular coordinate system. This process can be specifically expressed as:

[0121]

[0122]

[0123] Wherein, Δx represents the offset of the center of the light spot relative to the x-axis in the plane rectangular coordinate system; Δy represents the offset of the center of the light spot relative to the y-axis in the plane rectangular coordinate system; S i represents the radial offset of the light spot in the i-th vector direction; S j represents the radial offset of the spot in the jth vector direction; S k Indicates the radial offset of the light spot in the kth vector direction.

[0124] Furthermore, in an embodiment of the present application, a first angle of incidence of the incident light relative to the x-axis is calculated based on the sum of the first offsets and the target focal length according to the following formula. Simultaneously, a second angle of incidence of the incident light relative to the y-axis is calculated using the sum of the second offsets and the target focal length. The target focal length can be obtained by calculating the sum of the focal length of the focusing lens and the focal length of the microlens.

[0125] Among them, the incident angle θ of the incident light x ,θ y The calculation formula can be expressed as:

[0126]

[0127] Among them, θ x θ represents the first incident angle, which represents the angle between the projection of the incident light beam on the plane formed by the system axial direction and the x-axis in the plane rectangular coordinate system and the x-axis direction; y represents the second incident angle, which characterizes the angle between the projection of the incident light beam on the plane formed by the system axial direction and the y-axis in the plane rectangular coordinate system and the y-axis direction; f represents the target focal length, which is equal to the sum of the focal length F of the focusing lens and the focal length F′ of the microlens.

[0128] Optionally, to reduce the test error, the power points in all non-parallel radial directions are combined to solve the spot coordinates. Specifically, the calculation module combines all non-parallel radial directions in pairs, and based on the radial offset of the light spots in the two radial directions under each combination, obtains the position of the incident light spot on the plane coordinate system and calculates the average value, which is used as the final position of the incident light spot on the end face of the multi-core optical fiber, and then obtains the incident angle of the incident light. At this time, the incident angle θ of the incident light is x ,θ y The calculation formula can be expressed as:

[0129]

[0130] in, and They respectively represent the average value of the offset of the center point of the incident light spot relative to point O in the x-axis direction and the average value of the offset in the y-axis direction obtained by calculating the spot offset in two directions on the plane coordinate system.

[0131] The device of the embodiment of the present application, through a calculation program preset in the calculation module, combines the positional relationship of each lens in space to optically analyze and solve the radial offset of the light spot in each non-parallel radial direction within the end face of the multi-core optical fiber to obtain the incident angle of the incident light, which can achieve a wide range of incident light angle measurement and high-precision angle measurement results.

[0132] Continue to refer to Figure 3 , in an embodiment of the present application, the device further includes: a modulation and demodulation module 6;

[0133] The optical splitter module 5 further includes a communication beam output terminal 52 for outputting a communication beam; the communication beam output terminal 52 is connected to the modulation and demodulation module 6;

[0134] The modulation and demodulation module 6 is used to modulate the local communication laser of the device when the device serves as a signal transmitting end, and send the modulated signal to the communication beam output end 52 so as to send the modulated signal out through the central optical fiber 31;

[0135] The modulation and demodulation module 6 is further configured to demodulate the communication light beam outputted from the communication light beam output terminal 52 when the device serves as a signal receiving terminal.

[0136] Specifically, in an embodiment of the present application, the spatial laser communication device further includes a modem module, and the optical splitter module further includes a communication beam output terminal for outputting a communication beam. The communication beam output terminal is connected to the modem module to achieve integrated communication and angle measurement capabilities of the device. It will be appreciated that the communication beam output terminal is connected to the central optical fiber of the multi-core optical fiber and is used to output the communication beam coupled from the central optical fiber.

[0137] In an embodiment of the present application, the modulation and demodulation module may specifically include a signal modulation module, a signal demodulation module, and a circulator. The signal modulation module is used for local communication laser modulation at the transmitter, the signal demodulation module is used for communication beam demodulation at the receiver, and the circulator is used to combine the communication beam input to the signal demodulation module and the modulated beam output from the signal modulation module into a central optical fiber to achieve full-duplex communication within the same laser link.

[0138] In an embodiment of the present application, when the device serves as a signal transmitting end, the signal modulation module modulates the local communication laser and sends the modulated signal to the communication beam output end through the circulator, so as to send the modulated signal out through the central optical fiber.

[0139] When the device serves as a signal receiving end, the communication beam output from the communication beam output end is transmitted to the signal demodulation module through the circulator, and the signal demodulation module demodulates the communication beam.

[0140] The device of the embodiment of the present application can realize full-duplex communication function by introducing a modulation and demodulation module on the basis of realizing the angle measurement function of the device, and transmitting the communication light beam coupled by the central optical fiber to the modulation and demodulation module for processing. At the same time, based on the introduced microlens, the integrated performance of multi-core optical fiber angle measurement communication in the field of space laser communication is improved.

[0141] Figure 4 This is a schematic diagram of the structure of the microlens-based spatial laser angle measurement and communication integrated system provided by this application. Figure 4 As shown, in an embodiment of the present application, the system is composed of two communication terminals, wherein each communication terminal includes a pan-tilt head, a CMOS camera, a fast deflection mirror FSM and the aforementioned space laser communication device.

[0142] The communication equipment uses a CMOS camera to confirm its initial position and a pan / tilt-tilt system (PTZ) for wide-field deflection. The modem module in the space laser communication device transmits and receives the communication beam. For any communication terminal in the system, the transmitted beam emerges from the central optical fiber, passes through a microlens and a focusing lens, and then is transmitted to a fast deflection mirror (FSM). The FSM precisely controls the beam's deflection. After passing through the FSM, the beam propagates through free space to the next communication terminal. It then passes through the FSM, a focusing lens, and a microlens in that terminal before being transmitted to the beam splitter module, where it is split into the modem module and the incident beam angle calculation module. When the beam is incident normally, most of the light is coupled into the communication fiber, where communication is carried out via the modem module. When the beam angle deflects, the optical signal is received by non-central optical fibers. The calculation module calculates the angle and feeds it back to the FSM control system, deflecting the beam to achieve normal incidence.

[0143] The control method of the space laser communication device provided in the present application is described below. The control method of the space laser communication device described below and the embodiment of the space laser communication device described above can be referenced to each other.

[0144] Figure 5 This is a flow chart of a control method for a space laser communication device provided by the present application, which is applicable to any of the aforementioned space laser communication devices, such as Figure 5 As shown, the method includes:

[0145] Step 510, focusing the incident light using a focusing lens;

[0146] Step 520 , using a microlens to refocus the light beam focused by the focusing lens and transmit it to the multi-core optical fiber;

[0147] In step 530 , the calculation module determines the incident angle of the incident light based on the radial offsets of the light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber.

[0148] It should be understood that the method in the above embodiment is applied to the aforementioned space laser communication device, and the implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above method. The specific implementation method of the above method can refer to the above working process embodiment of the device, which will not be repeated here.

[0149] The control method of the space laser communication device of the embodiment of the present application introduces a microlens structure. The microlens refocuses the laser beam after being focused by the focusing lens, so that the incident laser is efficiently coupled into the central optical fiber. At the same time, the light beam passing through the non-central optical fiber can be used to measure the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber, and calculate the deviation angle of the incident light beam. In addition, all the core end faces of the multi-core optical fiber are in the same plane, and no changes in the optical fiber structure are required. The angular measurement range and accuracy can be effectively improved. The optical path system is simple, which is conducive to improving the communication performance of the device and greatly reduces the difficulty and cost of optical fiber processing.

[0150] Based on the content of the above embodiment, as an optional embodiment, the calculation module determines the incident angle of the incident light based on the radial offset of the light spot in multiple non-parallel radial directions in the end face of the multi-core optical fiber, including:

[0151] The calculation module calculates, in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, a first offset of each radial offset of the light spot relative to the abscissa axis of the plane rectangular coordinate system and a second offset of each radial offset of the light spot relative to the ordinate axis of the plane rectangular coordinate system based on the radial offset of the light spot in each non-parallel radial direction; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin;

[0152] The calculation module determines a first incident angle of the incident light relative to the abscissa axis based on the sum of the first offsets and the target focal length;

[0153] The calculation module determines a second incident angle of the incident light relative to the vertical axis based on the sum of the second offsets and the target focal length;

[0154] The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; the incident angle includes a first incident angle and a second incident angle.

[0155] Based on the content of the above embodiment, as an optional embodiment, the calculation module calculates, in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in each non-parallel radial direction, a first offset of each radial offset of the light spot relative to the abscissa axis of the plane rectangular coordinate system, and a second offset of each radial offset of the light spot relative to the ordinate axis of the plane rectangular coordinate system, including:

[0156] For any radial offset of each light spot, the calculation module performs a product operation on the radial offset of the light spot and the target cosine value to obtain a first offset of the radial offset of the light spot relative to the abscissa axis;

[0157] The calculation module performs a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the vertical coordinate axis;

[0158] The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any light spot radial offset and the total vector direction corresponding to each non-parallel radial direction.

[0159] Based on the content of the above embodiment, as an optional embodiment, the device further includes a spectrometer module; the spectrometer module includes a detection beam output end; the detection beam output end is connected to the calculation module; the method further includes:

[0160] The optical splitter module splits the communication beam and the detection beam output by the multi-core optical fiber, and outputs the detection beam through the detection beam output end; the communication beam is the beam of incident light coupled into the central optical fiber; the detection beam is the beam of incident light coupled into the non-central optical fiber;

[0161] The calculation module determines the radial offsets of the light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber based on the optical power information of the detection light beam.

[0162] Based on the content of the above embodiment, as an optional embodiment, the device further includes: a modulation and demodulation module; the optical splitting module further includes a communication beam output end for outputting the communication beam; the communication beam output end is connected to the modulation and demodulation module; the method further includes:

[0163] When the device acts as a signal transmitting end, the modulation and demodulation module modulates the local communication laser of the device and sends the modulated signal to the communication beam output end so as to transmit the modulated signal through the central optical fiber;

[0164] When the device serves as a signal receiving end, the modulation and demodulation module demodulates the communication light beam output from the communication light beam output end.

[0165] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0166] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0167] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

[0168] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0169] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0170] In addition, in the embodiments of the present application, the mathematical concepts mentioned include symmetry, equality, parallelism, and perpendicularity. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense. A small amount of deviation is allowed, and it is possible to be approximately symmetric, approximately equal, approximately parallel, or approximately perpendicular. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0171] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A space laser communication device, characterized in that: include: focusing lenses, microlenses, multi-core optical fibers, and computing modules; The multi-core optical fiber includes a central optical fiber and a plurality of non-central optical fibers distributed around the central optical fiber, and the end face of each non-central optical fiber is coplanar with the end face of the central optical fiber, and the distance between each non-central optical fiber and the central optical fiber is equal; The central axes of the focusing lens, the microlens, and the central optical fiber are collinear; the size of the microlens is smaller than that of the focusing lens; The focusing lens is used to focus the incident light; The microlens is used to refocus the light beam focused by the focusing lens and transmit it to the multi-core optical fiber; The calculation module is used to determine the incident angle of the incident light based on radial offsets of light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber.

2. The space laser communication device according to claim 1, characterized in that: The calculation module is specifically used for: In a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in each of the non-parallel radial directions, a first offset of each of the radial offsets of the light spots relative to the abscissa axis of the plane rectangular coordinate system and a second offset of each of the radial offsets of the light spots relative to the ordinate axis of the plane rectangular coordinate system are calculated; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin; determining a first incident angle of the incident light relative to the abscissa axis based on a sum of the first offsets and a target focal length; determining a second incident angle of the incident light relative to the longitudinal axis based on a sum of the second offsets and the target focal length; The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; and the incident angle includes the first incident angle and the second incident angle.

3. The space laser communication device according to claim 2, characterized in that: The calculation module is specifically used for: For any light spot radial offset among the light spot radial offsets, performing a product operation on the light spot radial offset and a target cosine value to obtain a first offset of the light spot radial offset relative to the abscissa axis; Performing a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the vertical coordinate axis; The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any one of the light spot radial offsets and the total vector direction corresponding to each of the non-parallel radial directions.

4. The space laser communication device according to claim 1, characterized in that: Also includes: Splitting module; The light splitting module includes a detection beam output end; the detection beam output end is connected to the calculation module; The optical splitting module is used to split the communication beam and the detection beam output by the multi-core optical fiber, and output the detection beam through the detection beam output end; the communication beam is the beam coupled by the incident light into the central optical fiber; the detection beam is the beam coupled by the incident light into the non-central optical fiber; The calculation module is further configured to determine radial offsets of light spots in multiple non-parallel radial directions within the end face of the multi-core optical fiber based on optical power information of the detection beam.

5. The space laser communication device according to claim 4, characterized in that: Also includes: Modem module; The optical splitting module includes a communication beam output end for outputting the communication beam; the communication beam output end is connected to the modulation and demodulation module; The modulation and demodulation module is used to modulate the local communication laser of the device when the device serves as a signal transmitting end, and send the modulated signal to the communication beam output end, so as to send the modulated signal out through the central optical fiber; The modulation and demodulation module is further configured to demodulate the communication light beam outputted from the communication light beam output end when the device serves as a signal receiving end.

6. The space laser communication device according to any one of claims 1 to 5, characterized in that: The radius of the microlens is greater than the radius of the central optical fiber and smaller than the distance between the central optical fiber and the non-central optical fiber.

7. A control method for a space laser communication device according to any one of claims 1 to 6, characterized in that: The method comprises: Focusing the incident light using the focusing lens; Using the microlens to refocus the light beam focused by the focusing lens and transmit it to the multi-core optical fiber; The calculation module determines the incident angle of the incident light based on radial offsets of light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber.

8. The control method of the space laser communication device according to claim 7, characterized in that: The calculation module determines the incident angle of the incident light based on radial offsets of light spots in multiple non-parallel radial directions in the end face of the multi-core optical fiber, including: The calculation module calculates, based on the radial offsets of the light spots in the non-parallel radial directions, a first offset of each radial offset of the light spots relative to the abscissa axis of the plane rectangular coordinate system, and a second offset of each radial offset of the light spots relative to the ordinate axis of the plane rectangular coordinate system in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber; the plane rectangular coordinate system takes the center point of the end face of the central optical fiber as its origin; The calculation module determines a first incident angle of the incident light relative to the abscissa axis based on a sum of the first offsets and a target focal length; The calculation module determines a second incident angle of the incident light relative to the longitudinal axis based on a sum of the second offsets and the target focal length; The target focal length is determined based on the focal length of the focusing lens and the focal length of the microlens; and the incident angle includes the first incident angle and the second incident angle.

9. The control method of the space laser communication device according to claim 8, characterized in that: The calculation module calculates, in a plane rectangular coordinate system constructed within the end face of the multi-core optical fiber, based on the radial offsets of the light spots in the non-parallel radial directions, a first offset of each of the radial offsets of the light spots relative to the abscissa axis of the plane rectangular coordinate system, and a second offset of each of the radial offsets of the light spots relative to the ordinate axis of the plane rectangular coordinate system, including: For any one of the light spot radial offsets, the calculation module performs a product operation on the light spot radial offset and a target cosine value to obtain a first offset of the light spot radial offset relative to the abscissa axis; The calculation module performs a product operation on the radial offset of any light spot and the target sine value to obtain a second offset of the radial offset of any light spot relative to the vertical coordinate axis; The target sine value and the target cosine value are both calculated based on the angle between the vector direction corresponding to any one of the light spot radial offsets and the total vector direction corresponding to each of the non-parallel radial directions.

10. The control method of the space laser communication device according to claim 7, characterized in that: The device further includes a spectroscopic module; the spectroscopic module includes a detection beam output end; the detection beam output end is connected to the calculation module; the method further includes: The optical splitting module splits the communication beam and the detection beam output by the multi-core optical fiber, and outputs the detection beam through the detection beam output end; the communication beam is the beam coupled by the incident light into the central optical fiber; the detection beam is the beam coupled by the incident light into the non-central optical fiber; The calculation module determines radial offsets of light spots in multiple non-parallel radial directions within the end face of the multi-core optical fiber based on the optical power information of the detection beam.

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