Space laser communication external field coaxial calibration device and method

Abstract

The invention discloses a space laser communication external field coaxial calibration device and method. The device comprises a laser, a collimating lens group, a spectroscope, a beam expander group, an optical wedge assembly, an optical filter, a receiving lens group and a detection camera. The laser is used for emitting first laser, and the first laser is collimated by the collimating lens group, projected by the spectroscope, expanded by the beam expander group, deflected by the optical wedge assembly and then emitted; the optical wedge assembly is further used for receiving second laser emitted by the to-be-detected laser terminal, the second laser passes through the optical wedge assembly, is subjected to beam shrinkage through the beam expanding lens set and then is turned by 90 degrees through the spectroscope, and after the second laser passes through the optical filter and the receiving lens set, light spots of the second laser converge on the imaging face of the detection camera. The device is simple and reliable in design, easy to implement, convenient to adjust, low in cost and high in practicability, can effectively detect the receiving and transmitting coaxiality of the equipment in an external field test, and is not influenced by shaft running of the device.

Description

Technical Field

[0001] This application relates to the field of space laser communication technology, and in particular to a space laser communication field coaxial calibration device and method. Background Technology

[0002] Laser communication, as a novel, high-speed, secure, and interference-resistant communication technology, has broad application prospects and significant strategic importance. Laser communication involves modulating a signal onto the frequency, amplitude, or phase of a laser beam for transmission. At the transmitting end, information is sent to an optical modulator connected to the laser. The modulator modulates the information onto the laser beam and transmits it through an optical transmitting antenna. At the receiving end, an optical receiving antenna receives the laser signal and sends it to a photodetector. The photodetector converts the laser signal into an electrical signal, which is then amplified, demodulated, and used to recover the original information.

[0003] Currently, laser communication systems largely adopt coaxial transceiver structures to improve communication quality, simplify system structure, and enhance communication efficiency. The coaxiality index is crucial for successful link establishment and communication. Laser communication coaxial transceivers require extremely high precision and stability to ensure alignment of the transmitting and receiving optical axes. In practical applications, laser communication coaxial transceiver systems may be affected by environmental factors such as temperature, vibration, and atmospheric disturbances, leading to a decrease in optical axis alignment accuracy and consequently affecting communication quality. Some laser terminals lack built-in coaxial self-calibration functions, and even those with self-calibration functions lack field testing equipment for problem localization in the event of a malfunction. Transceiver coaxiality testing generally requires a specialized high-precision laboratory; a simple and portable coaxial testing and calibration device is lacking for field testing. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a coaxial calibration device and method for space laser communication in the field, which solves the problem that existing devices are difficult to perform coaxial detection and calibration of transmission and reception in field tests.

[0005] To address the aforementioned technical problems, this application provides a coaxial calibration device for space laser communication, comprising a laser, a collimating lens group, a beam splitter, a beam expander group, an optical wedge assembly, a filter, a receiving lens group, and a detection camera. The laser emits a first laser beam, which is collimated by the collimating lens group, projected by the beam splitter, expanded by the beam expander group, and then deflected by the optical wedge assembly before exiting. The optical wedge assembly also receives a second laser beam emitted by the laser terminal under test. After passing through the optical wedge assembly, the second laser beam is reduced by the beam expander group, deflected by the beam splitter by 90 degrees, and then converged on the imaging surface of the detection camera after passing through the filter and the receiving lens group.

[0006] In some embodiments, the laser is a semiconductor laser, which uses fiber optic output and is connected to the fiber optic interface of the collimating lens group via an FC / APC connector fiber optic patch cord, and the emitting end face of the emitting fiber head of the semiconductor laser is located on the focal plane of the collimating lens group.

[0007] In some embodiments, the beam splitter is a dichroic beam splitter, which is used to transmit the first laser and reflect the second laser.

[0008] In some embodiments, the filter is a dual-transmission wavelength filter, wherein the transmission center wavelength of the dual-transmission wavelength filter includes the wavelength of the first laser and the wavelength of the second laser.

[0009] In some embodiments, the wavelength of the first laser is 915 nm, and the wavelength of the second laser is 976 nm.

[0010] In some embodiments, the optical wedge assembly is composed of two wedge mirrors placed back-to-back, the rotation angle of which is adjustable for precise angle adjustment of the outgoing and incoming light beams.

[0011] In some embodiments, the wedge angle of the optical wedge assembly is 2 degrees.

[0012] In some embodiments, the detection camera is used to read the centroid coordinates of the first laser and the second laser spot in real time.

[0013] This application also provides a coaxial calibration method for space laser communication in the field of application. Based on the aforementioned coaxial calibration device for space laser communication in the field of application, the method includes the following steps: device self-collimation; firstly, the coaxial calibration device for space laser communication in the field of application is placed on a tripod or a special adjustment frame, and the device is powered on, so that both the laser and the detection camera are in working condition; then, a corner bevel mirror is placed in front of the first laser emission port of the coaxial calibration device for space laser communication in the field of application; the first laser emitted by the laser is reflected back along its original path by the corner bevel mirror, and the beam splitter reflects the first laser into the detection camera, which reads the first laser's... First spot centroid coordinates; Device position adjustment: Adjust the direction of the tripod or special adjustment frame so that the first laser emission port is aligned with the second laser emission port of the laser terminal under test, turn on the laser terminal under test to emit the second laser, and then finely adjust the direction of the tripod or special adjustment frame so that the detection camera receives the spot of the second laser and adjusts it to be near the center of the field of view; Internal device adjustment: Fix the position of the tripod or special adjustment frame, and finely adjust the optical wedge assembly according to the real-time spot centroid position display of the spatial laser communication field coaxial calibration device so that the second spot centroid coordinates of the second laser are located at the first spot centroid coordinates.

[0014] In some embodiments, the method further includes: determining the position coordinates of the receiver detector spot of the laser terminal under test as the coaxial point of the laser terminal under test.

[0015] The beneficial effects of this application are as follows: This application discloses a coaxial calibration device and method for space laser communication field. The device includes a laser, a collimating lens group, a beam splitter, a beam expander group, an optical wedge assembly, a filter, a receiving lens group, and a detection camera. The laser is used to emit a first laser. After being collimated by the collimating lens group, the first laser is projected by the beam splitter, expanded by the beam expander group, and then deflected by the optical wedge assembly before being emitted. The optical wedge assembly is also used to receive a second laser emitted by the laser terminal under test. After passing through the optical wedge assembly, the second laser is reduced in size by the beam expander group, deflected by 90 degrees by the beam splitter, and then converged on the imaging surface of the detection camera after passing through the filter and the receiving lens group. When using this device for coaxial calibration in the field of space laser communication, the laser emits a first laser beam, which is collimated by a collimating lens group and then transmitted to the laser terminal under test via an optical antenna. The second laser beam emitted by the laser terminal under test is then adjusted to the coaxial point of the detection camera by the optical wedge assembly. The coaxial point of the laser terminal under test can be detected at the laser terminal under test. The device is simple and reliable in design, easy to implement, convenient to adjust, low in cost, and highly practical. It can effectively detect the coaxiality of the equipment in field tests and is not affected by the device's own axis deviation. Attached Figure Description

[0016] Figure 1This is a schematic diagram of an embodiment of the space laser communication field coaxial calibration device according to this application;

[0017] Figure 2 This is a flowchart of an embodiment of the space laser communication field coaxial calibration method according to this application;

[0018] Figure 3 This is a schematic diagram illustrating the self-collimation principle of a device in one embodiment of the space laser communication field coaxial calibration method of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0021] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0023] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0024] Figure 1 An embodiment of the space laser communication field coaxial calibration device of this application is shown, including a laser 1, a collimating lens group 2, a beam splitter 3, a beam expander group 4, an optical wedge assembly 5, a filter 6, a receiving lens group 7, and a detection camera 8. The laser 1 is used to emit a first laser. After being collimated by the collimating lens group 2, the first laser is projected by the beam splitter 3, expanded by the beam expander group 4, and then deflected by the optical wedge assembly 5 before being emitted. The optical wedge assembly 5 is also used to receive a second laser emitted by the laser terminal under test. After passing through the optical wedge assembly 5, the second laser is reduced in size by the beam expander group 4, deflected by the beam splitter 3 by 90 degrees, and then passes through the filter 6 and the receiving lens group 7. The spot of the second laser converges on the imaging surface of the detection camera 8.

[0025] In this embodiment, laser 1 is a semiconductor laser. The semiconductor laser uses fiber optic output and is connected to the fiber optic interface of the collimating lens group through an FC / APC connector fiber optic patch cord. The emitting end face of the emitting fiber head of the semiconductor laser is located on the focal plane of the collimating lens group.

[0026] In this embodiment, the wavelength of the first laser emitted by the semiconductor laser is 915 nm.

[0027] Furthermore, beam splitter 3 is a dichroic beam splitter, used to transmit the first laser and reflect the second laser.

[0028] Specifically, in this embodiment, the beam splitter has a transmission wavelength of 915nm and a transmittance of approximately 98%, and a reflection wavelength of 976nm and a reflectance of approximately 97%.

[0029] In some other embodiments, the semiconductor laser can be replaced according to the wavelength received by the actual laser terminal under test. The dichroic beam splitter can be replaced according to the laser terminal under test.

[0030] Furthermore, filter 6 is a dual-transmission wavelength filter, and the transmission center wavelength of the dual-transmission wavelength filter includes the wavelength of the first laser and the wavelength of the second laser.

[0031] In this embodiment, the wavelength of the first laser is 915nm, the wavelength of the second laser is 976nm, the bandwidth is 10nm, and the cutoff rate for other wavelength bands is OD5.

[0032] In this embodiment, the optical wedge assembly 5 is composed of two wedge mirrors placed back to back. The rotation angle of the wedge mirrors is adjustable, which is used to make precise angle adjustments to the outgoing beam and the incoming beam.

[0033] Furthermore, the wedge angle of the optical wedge assembly 5 is 2 degrees to ensure fine-tuning accuracy.

[0034] In this embodiment, the detection wavelength of the detection camera 8 includes the wavelength of the first laser emitted by the semiconductor laser and the wavelength of the second laser emitted by the laser terminal under test.

[0035] It should be noted that the detection camera 8 has real-time image processing capabilities, including the ability to read the centroid coordinates of the laser spot in real time. Therefore, the detection camera 8 can be used to read the centroid coordinates of the first and second laser spots in real time, and then, based on the centroid coordinates, complete the coaxial calibration of the space laser communication field coaxial calibration device.

[0036] Specifically, the inspection camera 8 uses a common silicon-based CMOS sensor, is 1 inch in size, has 4096*4096 pixels, and the centroid detection image processing program has a detection accuracy of 0.1 pixels.

[0037] Based on the same inventive concept, such as Figure 2 As shown, the present invention also provides a coaxial calibration method for space laser communication in the field, comprising the following steps:

[0038] Step S1: Device self-collimation.

[0039] It should be noted that the aforementioned space laser communication field coaxial calibration device needs to be self-calibrated using a corner bevel mirror during each field use to detect the actual transmit and receive coaxial point of the device under the current state.

[0040] Combination Figure 3 First, place the space laser communication field coaxial calibration device on a tripod or a special adjustment frame, and turn on the space laser communication field coaxial calibration device so that both the laser 1 and the detection camera 8 are in working condition. Then, place the corner bevel mirror 9 in front of the first laser emission port of the space laser communication field coaxial calibration device. After the first laser emitted by the laser 1 is reflected by the corner bevel mirror 9 along the original path, the beam splitter 3 will reflect a small part of the first laser into the detection camera 8, and read the centroid coordinates (x0, y0) of the first spot of the first laser.

[0041] Among them, the corner cone reflector 9 adopts the market standard corner cone reflector PS975M-M01B from Thorlabs, with an accuracy of less than 3” and a diameter of 25.4mm.

[0042] In this embodiment, this step can eliminate the coaxial error caused by the external environment and can detect the current coaxial reference point of the instrument in real time.

[0043] Step S2: Adjust the device position.

[0044] In this embodiment, the direction of the tripod or special adjustment frame is adjusted so that the first laser emission port is aligned with the second laser emission port of the laser terminal under test, the laser terminal under test is turned on to emit the second laser, and then the direction of the tripod or special adjustment frame is finely adjusted so that the detection camera 8 receives the light spot of the second laser and is adjusted to be near the center area of ​​the field of view.

[0045] Step S3: Internal adjustment of the device.

[0046] In this embodiment, the position of the fixed tripod or special adjustment frame is adjusted according to the real-time spot centroid position display of the space laser communication field coaxial calibration device, so that the second spot centroid coordinates of the second laser are located at the first spot centroid coordinates (x0, y0).

[0047] Furthermore, this method also includes: determining the position coordinates (x1, y1) of the receiving detector spot of the laser terminal under test as the coaxial point of the laser terminal under test.

[0048] It should be noted that the space laser communication field transceiver coaxial calibration device proposed in this application provides transceiver coaxial testing services for field tests. It is portable, easy to operate, and low in cost. However, it should not be used as a reference instrument. After the field test is completed, it should be tested, calibrated and confirmed in a professional high-precision laboratory.

[0049] Therefore, this application discloses a coaxial calibration device and method for space laser communication in the field. The device includes a laser, a collimating lens group, a beam splitter, a beam expander group, an optical wedge assembly, a filter, a receiving lens group, and a detection camera. The laser is used to emit a first laser. After being collimated by the collimating lens group, the first laser is projected by the beam splitter, expanded by the beam expander group, and then deflected by the optical wedge assembly before being emitted. The optical wedge assembly is also used to receive a second laser emitted by the laser terminal under test. After passing through the optical wedge assembly, the second laser is reduced in size by the beam expander group, deflected by 90 degrees by the beam splitter, and then converged on the imaging surface of the detection camera after passing through the filter and the receiving lens group. When using this device for coaxial calibration in the field of space laser communication, the laser emits a first laser beam, which is collimated by a collimating lens group and then transmitted to the laser terminal under test via an optical antenna. The second laser beam emitted by the laser terminal under test is then adjusted to the coaxial point of the detection camera by the optical wedge assembly. The coaxial point of the laser terminal under test can be detected at the laser terminal under test. The device is simple and reliable in design, easy to implement, convenient to adjust, low in cost, and highly practical. It can effectively detect the coaxiality of the equipment in field tests and is not affected by the device's own axis deviation.

[0050] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A coaxial calibration device for space laser communication in an external field, characterized in that, Includes laser, collimating lens group, beam splitter, beam expander group, optical wedge assembly, filter, receiving lens group, and detection camera; The laser is used to emit a first laser. After being collimated by the collimating lens group, the first laser is projected by the beam splitter, expanded by the beam expander group, and then deflected by the optical wedge assembly before exiting. The optical wedge assembly is also used to receive a second laser emitted by the laser terminal under test. After passing through the optical wedge assembly, the second laser is reduced by the beam expander group, deflected by the beam splitter by 90 degrees, and then passes through the filter and the receiving lens group. The spot of the second laser converges on the imaging surface of the detection camera.

2. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The laser is a semiconductor laser, which uses fiber optic output and is connected to the fiber optic interface of the collimating lens group via an FC / APC connector fiber optic patch cord. The emitting end face of the emitting fiber head of the semiconductor laser is located on the focal plane of the collimating lens group.

3. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The beam splitter is a dichroic beam splitter, which is used to transmit the first laser and reflect the second laser.

4. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The filter is a dual-transmission wavelength filter, and the transmission center wavelength of the dual-transmission wavelength filter includes the wavelength of the first laser and the wavelength of the second laser.

5. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The wavelength of the first laser is 915nm, and the wavelength of the second laser is 976nm.

6. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The optical wedge assembly is composed of two wedge-shaped mirrors placed back to back. The rotation angle of the wedge-shaped mirrors is adjustable, which is used to precisely adjust the angle of the outgoing and incoming light beams.

7. The space laser communication field coaxial calibration device according to claim 6, characterized in that, The wedge angle of the optical wedge assembly is 2 degrees.

8. The space laser communication field coaxial calibration device according to claim 1, characterized in that, The detection camera is used to read the centroid coordinates of the first laser and the second laser spot in real time.

9. A method for coaxial calibration in the field of space laser communication, characterized in that, Based on the space laser communication field coaxial calibration device according to any one of claims 1-8, the method includes the following steps: The device is self-collimated. First, the space laser communication field coaxial calibration device is placed on a tripod or a special adjustment frame, and the space laser communication field coaxial calibration device is turned on so that the laser and the detection camera are both in working condition. Then, the corner bevel mirror is placed in front of the first laser emission port of the space laser communication field coaxial calibration device. The first laser emitted by the laser is reflected back along the original path by the corner bevel mirror, and the beam splitter will reflect the first laser into the detection camera to read the centroid coordinates of the first spot of the first laser. The device position is adjusted by adjusting the direction of the tripod or special adjustment frame so that the first laser emission port is aligned with the second laser emission port of the laser terminal under test. The laser terminal under test is then turned on to emit the second laser. The direction of the tripod or special adjustment frame is then finely adjusted so that the detection camera receives the spot of the second laser and is adjusted to be near the center of the field of view. The device is internally adjusted to fix the position of the tripod or special adjustment frame. Based on the real-time spot centroid position display of the space laser communication field coaxial calibration device, the optical wedge assembly is finely adjusted so that the second spot centroid coordinates of the second laser are located at the first spot centroid coordinates.

10. The space laser communication field coaxial calibration method according to claim 9, characterized in that, The method further includes: determining the position coordinates of the receiver detector spot of the laser terminal under test as the coaxial point of the laser terminal under test.

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