A laser communication terminal with on-orbit focal plane compensation function and a testing method thereof

Abstract

The application relates to a laser communication terminal with an on-orbit focal plane compensation function and a testing method thereof, which comprises an angle reflector, an optical antenna, a beam splitter, a fast reflector, a collimator, a fiber amplifier, a beam splitter, a tracking detector, a fast reflector, a beam-reducing lens group, a focal plane compensation mechanism and a comprehensive processing module. The laser communication terminal adopts a focusing mechanism for focal plane compensation on an orbit, the focusing mechanism adjusts the focal plane position through receiving energy signal feedback, realizes accurate movement, the angle reflector is used for self-calibration, and the system performance is optimized. Through the on-orbit focal plane real-time compensation technology, the adaptability and reliability of the laser communication terminal are remarkably improved, the system debugging process is simplified, the universalization, standardization and integrated design are realized, and the on-orbit use efficiency of the laser communication terminal is improved.

Description

Technical Field

[0001] This invention belongs to the field of laser communication and relates to a laser communication terminal with on-orbit focal plane compensation function and its testing method. Background Technology

[0002] In the field of aerospace communication technology, laser communication terminals have become an important means of satellite communication due to their high speed, low latency, and high security. However, due to the complexity of the space environment, such as temperature variations, vibration, and radiation, laser communication terminals often face the problem of focal length changes in the optical system during on-orbit operation. These problems can lead to a decline in communication quality or even the inability to establish an effective communication link. Traditional focusing solutions mainly rely on ground debugging and experimental verification. Although these solutions can solve the problem to some extent, they are complex and inefficient, and the focusing mechanism and control system are complex, making it difficult to meet the requirements of integrated design and mass production capabilities of laser terminals, and even affecting the rapid and stable establishment of on-orbit links.

[0003] While existing technologies offer solutions for focal length variations in laser communication terminals, they still have significant limitations. For example, ground-based commissioning requires substantial manual intervention, which is not only time-consuming and labor-intensive but also makes it difficult to guarantee consistent performance after each commissioning. Furthermore, current focal plane compensation mechanisms for spaceborne products are large in size and have complex control systems, failing to meet the miniaturization and integration requirements of laser communication terminals and increasing system maintenance difficulty and risk. In addition, these methods are often only effective under specific conditions and have poor adaptability to dynamically changing space environments, failing to ensure long-term stable communication performance. Therefore, developing a miniaturized focal plane compensation technology that can automatically adapt to changes in the on-orbit environment is particularly important. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a laser communication terminal with on-orbit vacuum focal plane compensation function. This provides a solution and test method for solving the problem of focal length change of the optical system after the laser communication terminal enters orbit, and can effectively improve the development efficiency of laser terminals and the on-orbit focal plane compensation effect.

[0005] The technical solution adopted in this invention is as follows: This invention discloses a laser communication terminal with on-orbit focal plane compensation function, comprising: a corner reflector, an optical antenna, a first beam splitter, a second beam splitter, a first fast-reflecting mirror, a tracking detector, a beam-shrinking mirror group, a focal plane compensation mechanism, and a comprehensive processing module; wherein, The optical antenna reflects or transmits spatial laser signals reflected by corner reflectors or emitted by external target laser terminals, and then reflects them through the first beam splitter before entering the second beam splitter; it adjusts the angle of receiving spatial laser signals according to the antenna pointing angle control command sent by the integrated processing module. The second beam splitter splits the received signal light according to a certain ratio, with one part of the beam incident on the tracking detector and the other part of the beam incident on the first fast reflector. The tracking detector is used to calculate the real-time position of the received light spot and output the position information of the received light signal to the integrated processing module. The integrated processing module calculates the tracking error based on the position information; based on the tracking error, it sends an antenna pointing angle control command to the optical antenna and a small angle adjustment control command to the first fast reflector; it demodulates the compensated optical signal sent by the focal plane compensation mechanism to obtain the target signal; and based on the energy of the optical signal sent by the focal plane compensation mechanism, it sends a position compensation control command to the focal plane compensation mechanism. The first fast reflector adjusts the propagation direction of the incident beam according to the small angle adjustment control command and sends it to the beam shrinking mirror group; The beam-shrinking mirror group shrinks the beam reflected by the first fast reflector and then transmits it to the receiving optical fiber loaded by the focal plane compensation mechanism. The focal plane compensation mechanism adjusts the position of the receiving optical fiber along the optical axis according to the position compensation control command sent by the integrated processing module, so that the focal point of the beam after being converged by the beam shrinking lens group can coincide with the end face of the receiving optical fiber, and the compensated optical signal energy is adjusted to the maximum before being output to the integrated processing module.

[0006] Furthermore, the aforementioned terminal also includes a second fast reflector, a collimator, and an optical fiber amplifier; wherein, The integrated processing module outputs the modulated laser signal, which then enters the fiber amplifier. The fiber optic amplifier amplifies the optical signal power of the modulated laser signal and outputs it to the collimator. The collimator collimates the amplified optical signal and then emits the collimated beam to the second fast reflector. The second fast reflector, after adjusting the direction of the beam's emission according to the small-angle control command sent by the integrated processing module, sends the signal to the optical antenna through the first beam splitter. The optical antenna expands the beam sent by the first beam splitter to transmit the laser signal to the target terminal.

[0007] Furthermore, in the aforementioned terminal, the corner reflector is installed on the terminal body or a nearby support, within the terminal's field of view; the optical antenna is an off-axis telescope or a transmission telescope; the beam splitter is a polarizing beam splitter, which splits the incident light into two beams: one beam is vertically polarized light, and the other beam is horizontally polarized light; the collimator is a reflective or transmission fiber optic collimator; the corner reflector consists of three mutually perpendicular plane mirrors, used to return the incident light along its original path.

[0008] Furthermore, in the aforementioned terminal, the tracking detector is a four-quadrant detector or a CMOS camera; the focal plane compensation mechanism is a piezoelectric linear motion mechanism with a position sensor, used to drive the receiving optical fiber to move back and forth along the optical axis to achieve focal plane closed-loop compensation; the beam shrinking lens group is a space light to fiber optic coupling device, used to couple the space beam into a single-mode polarization-maintaining fiber.

[0009] Furthermore, in the aforementioned terminal, the fast reflector is a voice coil mirror or a piezoelectric ceramic mirror, with an angular travel range of not less than 1 mrad and an execution accuracy of not less than 0.1 urad.

[0010] Furthermore, in the aforementioned terminal, the optical fiber amplifier is a polarization-maintaining optical fiber amplifier with a maximum output optical power of at least 6W and continuously adjustable power, and an operating wavelength of 1550nm.

[0011] Furthermore, in the aforementioned terminal, the transmission-to-reflection beam splitting ratio of the beam splitter is 1:1 to 1:10.

[0012] Furthermore, in the aforementioned terminal, the integrated processing module is used to generate intensity-modulated or phase-modulated emitted laser signals in the 900nm~1550nm band, and to detect, sample, demodulate, and decode the received intensity-modulated or phase-modulated laser signals in the 900nm~1550nm band.

[0013] This invention discloses an on-orbit self-calibration test method for a laser communication terminal with on-orbit focal plane compensation function, comprising: S1. Confirm the power-on and temperature control status of the laser terminal; S2. Set the first and second fast reflectors to be coaxial; S3. Drive the optical antenna to point to the corner reflector, so that the optical antenna's transmission outlet rotates to the self-calibration angle position; S4. Set the signal light emitted by the laser in the integrated processing module, and set the signal wavelength and modulation parameters; S5. Turn on the tracking detector and set the exposure and gain parameters of the tracking detector according to the target requirements. S6. Select the receiving channel of the optical antenna according to the requirements; S7. Set the fiber optic amplifier parameters and turn on the fiber optic amplifier; S8. Adjust the focal plane compensation mechanism to the position where the received optical signal energy is strongest and maintain it; S9. The integrated processing module determines whether the transmitted laser telemetry status, the tracking detector telemetry, and the received signal light energy meet the requirements. If not, repeat steps S3 to S8. If yes, the test passes.

[0014] Compared with the prior art, the present invention has the following advantages: (1) The present invention adopts an integrated design. By setting a focusing mechanism in the coupling receiving branch of the optical head system, the receiving fiber end face and the system coupling focal plane can achieve optimal matching under different environments, and on-orbit focal plane real-time compensation can be realized.

[0015] (2) The present invention adopts a closed-loop control design for the position of the focusing mechanism, which associates the focus mechanism focal plane position feedback signal with the system received energy signal to form a closed-loop control. The optimal matching of the focal position is achieved by the precise movement of the focusing mechanism.

[0016] (3) The present invention uses a corner reflector for laser terminal self-calibration. By transmitting and receiving signal light, the coupling efficiency of the receiving branch of the system can be self-checked, and the focal plane position can be initially optimized according to the received energy signal, laying the foundation for establishing inter-satellite links and improving the link establishment efficiency. Attached Figure Description

[0017] Figure 1 This is a block diagram illustrating the composition principle of the system of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, this invention discloses a laser communication terminal with on-orbit focal plane compensation function, comprising: a corner reflector, an optical antenna, a first beam splitter, a second beam splitter, a first fast reflector, a tracking detector, a beam-shrinking mirror group, a focal plane compensation mechanism, and a comprehensive processing module; wherein, The optical antenna reflects or transmits spatial laser signals reflected by corner reflectors or emitted by external target laser terminals, and then reflects them through the first beam splitter before entering the second beam splitter; it adjusts the angle of receiving spatial laser signals according to the antenna pointing angle control command sent by the integrated processing module. The second beam splitter splits the received signal light according to a certain ratio, with one part of the beam incident on the tracking detector and the other part of the beam incident on the first fast reflector. The tracking detector is used to calculate the real-time position of the received light spot and output the position information of the received light signal to the integrated processing module. The integrated processing module calculates the tracking error based on the position information; based on the tracking error, it sends an antenna pointing angle control command to the optical antenna and a small angle adjustment control command to the first fast reflector; it demodulates the compensated optical signal sent by the focal plane compensation mechanism to obtain the target signal; and based on the energy of the optical signal sent by the focal plane compensation mechanism, it sends a position compensation control command to the focal plane compensation mechanism. The first fast reflector adjusts the propagation direction of the incident beam according to the small angle adjustment control command and sends it to the beam shrinking mirror group; The beam-shrinking mirror group shrinks the beam reflected by the first fast reflector and then transmits it to the receiving optical fiber loaded by the focal plane compensation mechanism. The focal plane compensation mechanism adjusts the position of the receiving optical fiber along the optical axis according to the position compensation control command sent by the integrated processing module, so that the focal point of the beam after being converged by the beam shrinking lens group can coincide with the end face of the receiving optical fiber, and the compensated optical signal energy is adjusted to the maximum before being output to the integrated processing module.

[0020] According to the compensation control command sent by the integrated processing module, the focal plane position of the receiving optical fiber is compensated. Specifically, after the focusing mechanism is powered on, it performs position zeroing, and the zero point position is the theoretical focal plane position. After zeroing is achieved, the position of the focusing mechanism can be optimized on-orbit according to the self-calibration test method. That is, the integrated processing module performs position optimization according to the set motion step amount based on the telemetry of the signal light energy received at the current position of the focusing mechanism, with the aim of maximizing the received signal light energy. The position information of the focusing mechanism when the signal light energy reaches its maximum is identified, and the mechanism is kept in that position to complete the on-orbit focal plane compensation.

[0021] Preferably, it further includes a second fast reflector, a collimator, and an optical fiber amplifier; wherein, The integrated processing module outputs the modulated laser signal, which then enters the fiber amplifier. The fiber optic amplifier amplifies the optical signal power of the modulated laser signal and outputs it to the collimator. The collimator collimates the amplified optical signal and then emits the collimated beam to the second fast reflector. The second fast reflector, after adjusting the direction of the beam's emission according to the small-angle control command sent by the integrated processing module, sends the signal to the optical antenna through the first beam splitter. The optical antenna expands the beam sent by the first beam splitter to transmit the laser signal to the target terminal.

[0022] Preferably, the corner reflector is installed on the terminal body or a nearby bracket, within the terminal's field of view; the optical antenna is an off-axis telescope or a transmission telescope; the beam splitter is a polarizing beam splitter, which splits the incident light into two beams: one beam is vertically polarized light and the other beam is horizontally polarized light; the collimator is a reflective or transmission fiber optic collimator; the corner reflector consists of three mutually perpendicular plane mirrors, used to return the incident light along its original path.

[0023] Preferably, the tracking detector is a four-quadrant detector or a CMOS camera; the focal plane compensation mechanism is a piezoelectric linear motion mechanism with a position sensor, used to drive the receiving fiber to move back and forth along the optical axis to achieve focal plane closed-loop compensation; the beam shrinking lens group is a space light to fiber optic coupling device, used to couple the space beam into a single-mode polarization-maintaining fiber.

[0024] Preferably, the fast reflector is a voice coil mirror or a piezoelectric ceramic mirror, with an angular travel range of not less than 1 mrad and an execution accuracy of not less than 0.1 urad.

[0025] Preferably, the fiber amplifier is a polarization-maintaining fiber amplifier with a maximum output optical power of at least 6W and continuously adjustable power, and an operating wavelength of 1550nm.

[0026] Preferably, the transmission to reflection beam splitting ratio of the beam splitter is 1:1 to 1:10.

[0027] Preferably, the integrated processing module is used to generate intensity-modulated or phase-modulated emitted laser signals in the 900nm~1550nm band, and to detect, sample, demodulate and decode the received intensity-modulated or phase-modulated laser signals in the 900nm~1550nm band.

[0028] This invention discloses an on-orbit self-calibration test method for a laser communication terminal with on-orbit focal plane compensation function, comprising: S1. Confirm the power-on and temperature control status of the laser terminal; S2. Set the first and second fast reflectors to be coaxial; S3. Drive the optical antenna to point to the corner reflector, so that the optical antenna's transmission outlet rotates to the self-calibration angle position; S4. Set the signal light emitted by the laser in the integrated processing module, and set the signal wavelength and modulation parameters; S5. Turn on the tracking detector and set the exposure and gain parameters of the tracking detector according to the target requirements. S6. Select the receiving channel of the optical antenna according to the requirements; S7. Set the fiber optic amplifier parameters and turn on the fiber optic amplifier; S8. Adjust the focal plane compensation mechanism to the position where the received optical signal energy is strongest and maintain it; S9. The integrated processing module determines whether the transmitted laser telemetry status, the tracking detector telemetry, and the received signal light energy meet the requirements. If not, repeat steps S3 to S8. If yes, the test passes.

[0029] Example In this embodiment, when the terminal receives a laser signal, the spatial laser signal beam emitted by the target terminal enters the optical antenna. After reflection or transmission through the optical antenna, it is reflected by a beam splitter and then enters the beam splitter, which splits the received signal light according to a certain ratio. A portion of the beam is incident on a tracking detector, which calculates the real-time position of the received spot. The tracking detector outputs the received optical signal position information to the integrated processing module, which calculates the tracking error and controls the optical antenna to adjust the beam direction at a large angle and the fast reflector to adjust the propagation direction of another portion of the beam at a small angle. This portion of the beam is then coupled into the receiving optical fiber of the focal plane compensation mechanism via a beam-shrinking lens group, and subsequently output to the integrated processing module for demodulation of communication data. The integrated processing module can simultaneously identify the energy of the received signal light and display the beam energy information through telemetry. The beam energy information is correlated with the motion control of the focal plane compensation mechanism, enabling closed-loop control within the mechanism's motion range and achieving optimal focal plane position compensation.

[0030] When emitting a laser signal, the integrated processing module outputs a modulated laser signal with either intensity or phase modulation. The modulated signal enters an optical amplifier for power amplification, and then the amplifier inputs the signal to a collimator. The collimator enables the spatial beam of the laser signal to exit, directing the beam onto a fast reflector. Under the control of the integrated processing module, the fast reflector makes minute adjustments to the direction of the emitted beam to achieve pre-aiming. The beam then enters a beam splitter, which establishes a common optical path for both the emitted and received lasers. The beam then enters an optical antenna to expand the spatial beam and compress the beam divergence angle. Finally, the beam undergoes large-angle pointing adjustment by the optical antenna to complete the laser signal transmission to the target terminal.

[0031] The corner reflector is installed on the terminal body or a nearby bracket, within the terminal's field of view. Before establishing a link, each laser communication terminal can perform self-calibration using the corner reflector. The pointing angle of the optical antenna is adjusted to align with the corner reflector, allowing the emitted laser beam to enter. The corner reflector reflects the beam parallel to the optical antenna, and the beam then passes back into the rear optical path, achieving self-transmission and reception of the signal and beacon beams. The beam is coupled through a beam-shrinking lens group into the receiving fiber of the focal plane compensation mechanism, and then output to the integrated processing module. Through closed-loop control of the beam energy and the position of the focal plane compensation mechanism, preliminary focal plane position optimization can be achieved.

[0032] Furthermore, this invention provides an on-orbit self-calibration test method for a laser communication terminal, comprising the following steps: 1) On-orbit self-calibration should be performed after the laser terminal has been unlocked and its health status checked. During the on-orbit operation of the laser terminal, regular on-orbit maintenance should be carried out based on pointing error and link status. During on-orbit maintenance, laser terminal self-calibration tests should be conducted. The satellite platform should ensure attitude stability, and the test arc should avoid the influence of direct sunlight. Confirm the power-on and temperature control status of the laser terminal (if the laser is always powered on in orbit, proceed directly to the next steps). 2) Set the precision tracking and advance rapid response directions to the coaxial position of the transmitter and receiver (the advance rapid response compensation parameters corresponding to the same self-calibration angle on the ground can be used for setting). 3) Release the soft limit of the pointing angle, drive the servo mechanism to point the corner reflector, and rotate the optical antenna transmission outlet to the self-calibration angle position; 4) Set the laser in the integrated processing module to emit signal light, and set the signal wavelength and modulation parameters (modulation code rate, modulation data source). 5) Turn on the relevant tracking detector and set the tracking detector exposure parameters and gain parameters (initially, the same parameters as during ground calibration can be used). 6) Select the receiving channel of the optical antenna (if this function is available, you need to set it up; otherwise, you can proceed to the next step). 7) Set the optical amplifier parameters (the power control value uses the ground self-calibration time calibration data), turn on the optical amplifier, and set the power value to be the same as the value during ground testing; 9) For the focal plane compensation mechanism, adjust the mechanism position based on the position after entering the rail. After power-on, perform zeroing to return to the initial position, and then perform bidirectional position optimization based on the energy feedback from the integrated management module to find and maintain the position with the strongest coupling energy; 10) Check and record the capture detector error. Compare it with ground test data and estimate the optical axis change by the change in error. 11) Perform self-calibrated closed-loop communication test (used during processor communication status self-test; optical axis deviation calibration is not required). 12) After the test is completed, turn off the optical amplifier, laser and capture detector in sequence, so that the optical antenna returns to the safe docking position. Then, shut down the servo drive, shut down the integrated management module and power off the equipment.

[0033] In this embodiment, the effective aperture of the corner reflector is φ47mm, the overall angular accuracy is 3 arcseconds, and it is equipped with a neutral density filter with OD3@1550nm.

[0034] In this embodiment, the optical antenna is an off-axis reflecting telescope.

[0035] In this embodiment, the beam splitter is a 1550nm band beam splitter that transmits p-light and reflects s-light.

[0036] In this embodiment, the fast reflector is a piezoelectric ceramic galvanometer with an angle execution range of 3 mrad and an execution accuracy of 0.05 urad.

[0037] In this embodiment, the collimator used is a spatial light transmission collimator with a wavelength of 1550nm.

[0038] In this embodiment, the fiber amplifier is a polarization-maintaining fiber amplifier with a maximum output optical power of 5W that is continuously adjustable and an operating wavelength of 1550nm.

[0039] In this embodiment, the beam splitter is a beam splitter with a transmission-to-reflection beam splitting ratio of 1:1 and a center wavelength of 1550nm.

[0040] In this embodiment, the tracking detector uses a four-quadrant QD detector and a CMOS detector, which are split in a 9:1 ratio.

[0041] In this embodiment, the beam-shrinking lens group uses a spatial light transmission collimator with a wavelength of 1550nm.

[0042] In this embodiment, the focal plane compensation mechanism is a piezoelectric ceramic linear motion mechanism with a photoelectric encoder, which is used to drive the receiving optical fiber to move back and forth along the optical axis, thereby realizing focal plane closed-loop compensation.

[0043] In this embodiment, the integrated processing module generates a BPSK phase-modulated transmitted laser signal in the 1550nm band, with a maximum communication rate of 2Gbps. It can also generate OOK intensity-modulated transmitted laser signals at 1MHz and 1.7MHz. The receiving wavelength is 1550nm, the communication mode is BPSK phase modulation, and it supports a signal demodulation capability of up to 2Gbps. Simultaneously, it supports closed-loop control of the servo mechanism, fast reflector, and focal plane compensation mechanism.

[0044] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0045] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A laser communication terminal with on-orbit focal plane compensation function, characterized in that, It includes: a corner reflector, an optical antenna, a first beam splitter, a second beam splitter, a first fast-reflecting mirror, a tracking detector, a beam-shrinking lens group, a focal plane compensation mechanism, and an integrated processing module; among which, The optical antenna reflects or transmits spatial laser signals reflected by corner reflectors or emitted by external target laser terminals, and then reflects them through the first beam splitter before entering the second beam splitter; it adjusts the angle of receiving spatial laser signals according to the antenna pointing angle control command sent by the integrated processing module. The second beam splitter splits the received signal light according to a certain ratio, with one part of the beam incident on the tracking detector and the other part of the beam incident on the first fast reflector. The tracking detector is used to calculate the real-time position of the received light spot and output the position information of the received light signal to the integrated processing module. The integrated processing module calculates the tracking error based on the position information; based on the tracking error, it sends an antenna pointing angle control command to the optical antenna and a small angle adjustment control command to the first fast reflector; it demodulates the compensated optical signal sent by the focal plane compensation mechanism to obtain the target signal; and based on the energy of the optical signal sent by the focal plane compensation mechanism, it sends a position compensation control command to the focal plane compensation mechanism. The first fast reflector adjusts the propagation direction of the incident beam according to the small angle adjustment control command and sends it to the beam shrinking mirror group; The beam-shrinking mirror group shrinks the beam reflected by the first fast reflector and then transmits it to the receiving optical fiber loaded by the focal plane compensation mechanism. The focal plane compensation mechanism adjusts the position of the receiving optical fiber along the optical axis according to the position compensation control command sent by the integrated processing module, so that the focal point of the beam after being converged by the beam shrinking lens group can coincide with the end face of the receiving optical fiber, and the compensated optical signal energy is adjusted to the maximum before being output to the integrated processing module.

2. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that, It also includes a second fast reflector, a collimator, and an optical fiber amplifier; among which, The integrated processing module outputs the modulated laser signal, which then enters the fiber amplifier. The fiber optic amplifier amplifies the optical signal power of the modulated laser signal and outputs it to the collimator. The collimator collimates the amplified optical signal and then emits the collimated beam to the second fast reflector. The second fast reflector, after adjusting the direction of the beam's emission according to the small-angle control command sent by the integrated processing module, sends the signal to the optical antenna through the first beam splitter. The optical antenna expands the beam sent by the first beam splitter to transmit the laser signal to the target terminal.

3. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The corner reflector is installed on the terminal body or a nearby bracket, within the terminal's field of view; the optical antenna is an off-axis telescope or a transmission telescope; the beam splitter is a polarizing beam splitter, which splits the incident light into two beams: one beam is vertically polarized light, and the other beam is horizontally polarized light; the collimator is a reflective or transmission fiber optic collimator; the corner reflector consists of three mutually perpendicular plane mirrors, used to return the incident light along its original path.

4. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The tracking detector is a four-quadrant detector or a CMOS camera; the focal plane compensation mechanism is a piezoelectric linear motion mechanism with a position sensor, used to drive the receiving optical fiber to move back and forth along the optical axis to achieve focal plane closed-loop compensation; the beam shrinking lens group is a space light to fiber optic coupling device, used to couple the space beam into a single-mode polarization-maintaining fiber.

5. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The fast reflector is a voice coil mirror or a piezoelectric ceramic mirror, with an angular travel range of not less than 1 mrad and an execution accuracy of not less than 0.1 urad.

6. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The fiber amplifier is a polarization-maintaining fiber amplifier with a maximum output optical power of at least 6W and continuously adjustable power, and an operating wavelength of 1550nm.

7. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The transmission-to-reflection beam splitter ratio of the beam splitter is 1:1 to 1:

10.

8. A laser communication terminal with on-orbit focal plane compensation function according to claim 1, characterized in that: The integrated processing module is used to generate intensity-modulated or phase-modulated emitted laser signals in the 900nm~1550nm band, and to detect, sample, demodulate and decode the received intensity-modulated or phase-modulated laser signals in the 900nm~1550nm band.

9. The on-orbit self-calibration test method for a laser communication terminal with on-orbit focal plane compensation function as described in claim 1, characterized in that, include: S1. Confirm the power-on and temperature control status of the laser terminal; S2. Set the first and second fast reflectors to be coaxial; S3. Drive the optical antenna to point to the corner reflector, so that the optical antenna's transmission outlet rotates to the self-calibration angle position; S4. Set the signal light emitted by the laser in the integrated processing module, and set the signal wavelength and modulation parameters; S5. Turn on the tracking detector and set the exposure and gain parameters of the tracking detector according to the target requirements. S6. Select the receiving channel of the optical antenna according to the requirements; S7. Set the fiber optic amplifier parameters and turn on the fiber optic amplifier; S8. Adjust the focal plane compensation mechanism to the position where the received optical signal energy is strongest and maintain it; S9. The integrated processing module determines whether the transmitted laser telemetry status, the tracking detector telemetry, and the received signal light energy meet the requirements. If not, repeat steps S3 to S8. If yes, the test passes.

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