An optical path optical alignment device and method for a laser communication terminal

Abstract

The present invention provides an optical path optical alignment device for a laser communication terminal, belonging to the technical field of optical alignment. It includes a light pen fixed shell, an infrared light pen, a light pen positioning seat, and an adapter seat. A positioning light outlet is provided on the light pen fixed shell, and a positioning light inlet is provided on the light pen positioning seat; the infrared light pen is detachably installed inside the light pen fixed shell, and the light pen fixed shell and the light pen positioning seat are detachably fixed; the adapter seat is detachably installed on the top of the laser communication terminal, the light pen positioning seat is detachably connected to the adapter seat, and a through hole is provided on the adapter seat; the parallel infrared laser emitted by the infrared light pen passes through the positioning light outlet, the positioning light inlet, and the adapter seat, and enters the laser communication terminal through the light inlet hole of the laser terminal; The present invention also provides an alignment method, which solves the problems of cumbersome operation and long time consumption in the optical path alignment process of the existing laser communication terminal.

Description

Technical Field

[0001] The present invention relates to the technical field of optical alignment, and particularly to an optical path optical alignment device and method for a laser communication terminal. Background Art

[0002] The accuracy of the optical path of a laser communication terminal determines multiple indicators such as the tracking accuracy, acquisition time, acquisition probability, and acquisition field of view range during fine tracking between the laser terminal and the transmitter. Since these indicators are extremely precise, and the rear optical path contains multiple reflectors and beam splitters, the optical path is very complex. During the alignment process, it is often difficult to determine the components with alignment errors and the adjustment methods required only by measuring instruments, which causes great trouble for the alignment of each component in the optical path.

[0003] The traditional alignment methods for each component in the rear optical path of a laser communication terminal mainly include the following steps:

[0004] First step: Establish a Cartesian coordinate system on the bottom surface of the rear optical path, and calculate the position of the component in the coordinate axes of the bottom plane through theoretical calculation.

[0005] Second step: Use an autocollimator to accurately mark the angle and position where the beam splitter is to be installed.

[0006] Third step: Install the component at the marked position.

[0007] Fourth step: Use an autocollimator to confirm whether the position of each marked beam splitter is accurate. If the position is correct, jump to step six; if the position is incorrect, repeat steps four and five.

[0008] Fifth step: Adjust the optical path direction of the beam splitter by grinding the beam splitter chassis.

[0009] Sixth step: Assemble the optical path part of the optical machine of the laser communication terminal.

[0010] Seventh step: Transmit a beacon light through the transmitter.

[0011] Eighth step: Observe the position of the cursor on the CCD display screen. If the cursor is located at the center of the field of view, the alignment is qualified; if there is a deviation, it is necessary to disassemble the rear optical path of the laser communication terminal, open the rear optical path, and repeat steps four to eight until the alignment is qualified.

[0012] Since the position accuracy of the optical path beam splitter has a great influence on the optical path, a large error in the position of the beam splitter will cause the optical path to be misaligned. It is difficult to ensure the accuracy after the installation of the beam splitter only by relying on the autocollimator. It is found in the actual alignment process that for the beam splitter within the measurement error range of the autocollimator, the optical path may be misaligned due to the uneven chassis. Moreover, during the alignment process of the optical components in the rear optical path of the laser communication terminal, the installation angles of each beam splitter need to be adjusted. Since the actual situation of the optical path cannot be visually confirmed, installation deviations often occur during the alignment process, which is cumbersome and time-consuming. There is an urgent need in the industry for a method for aligning the optical components in the rear optical path of the laser communication terminal.

[0013] The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0014] The present invention provides an optical path optical alignment device and method for a laser communication terminal, aiming to solve the problems of cumbersome operation and long time consumption in the optical path alignment process of the existing laser communication terminal.

[0015] An optical path optical alignment device for a laser communication terminal, comprising a light pen fixing shell, an infrared light pen, a light pen positioning seat and an adapter seat. A positioning light outlet is provided on the light pen fixing shell, and a positioning light inlet is provided on the light pen positioning seat; the infrared light pen is detachably installed in the light pen fixing shell, and the light pen fixing shell and the light pen positioning seat are detachably fixed; the adapter seat is detachably installed on the top of the laser communication terminal, the light pen positioning seat is detachably connected to the adapter seat, and a through hole is provided on the adapter seat; the parallel infrared laser emitted by the infrared light pen passes through the positioning light outlet, the positioning light inlet and the adapter seat, and enters the laser communication terminal through the laser terminal light inlet hole; the bottom mounting surface of the laser communication terminal is a plane, the laser terminal light inlet hole is provided on the top, its axis is perpendicular to the bottom mounting surface, and the laser terminal light outlet hole is provided on the side wall of the laser communication terminal along the direction parallel to the bottom mounting surface in the axial direction; a beam splitter, a PZT, a receiver, a CCD infrared camera and a optical power meter are arranged inside the laser communication terminal. There are at least two beam splitters. After the infrared laser emitted by the infrared light pen enters the laser communication terminal along the laser terminal light inlet hole, it passes through the beam splitter and the PZT to change the optical path and then hits the receiver and the CCD infrared camera. The optical power meter is connected to the rear end of the receiver; the CCD infrared camera is used to display the received laser spot on the display screen in real time; the PZT is used for the reflection of the optical path; the receiver is used as the communication receiver of the laser communication terminal and is used to collect the received parallel light into the optical fiber for transmission; the optical power meter is used to detect the optical signal power entering the communication receiver in real time. Whether the beam entering the receiver split by the beam splitter is aligned with the receiver is judged by observing the optical power value received by the optical power meter; the alignment condition of the beam splitter is confirmed by observing the value of the optical power meter and the spot on the display screen of the CCD infrared camera.

[0016] Further, the optical path optical alignment device further comprises an adjustment intermediate seat, which is detachably connected to the light pen fixing shell and the adapter seat respectively. A through hole is provided on the adjustment intermediate seat for the infrared laser to pass through.

[0017] Further, the CCD infrared camera adopts an InGaAs short-wave infrared uncooled focal plane detection camera.

[0018] Further, the PZT adopts an electromagnetic galvanometer of piezoelectric ceramics.

[0019] Further, a threaded connection is adopted between the light pen fixing shell and the light pen positioning seat.

[0020] Based on the same concept, the present invention also proposes an optical path optical alignment method for a laser communication terminal, adopting the above optical path optical alignment device, comprising the following steps:

[0021] S1. Establish a Cartesian coordinate system on the bottom surface of the rear optical path, and calculate the positions of the components in the coordinate axes of the bottom plane through theoretical calculation;

[0022] S2. Precisely mark the angles and positions for installing each beam splitter using an autocollimator;

[0023] S3. Install each beam splitter at the marked positions;

[0024] S4. Turn on the infrared light pen and observe whether the installation and adjustment are qualified by the values of the CCD infrared camera and the optical power meter;

[0025] S4.1. Turn on the infrared light pen to emit infrared laser. Observe the position of the cursor on the display screen of the CCD infrared camera. If the cursor is at the center of the field of view, the optical path generated after refraction does not deflect and enters the position of the beam splitter in the infrared camera correctly; if it is not at the center of the field of view, the position of the above beam splitter is inaccurate, and adjust the position of the beam splitter according to step S5;

[0026] S4.2. Observe the values on each optical power meter. If the power of each optical power meter reaches the expected power, the installation and adjustment are qualified and the installation and adjustment are completed; if it does not reach the expected power, the position of the beam splitter where the optical path generated after refraction does not deflect and enters the corresponding optical power meter is inaccurate, and adjust the position of the beam splitter according to step S5;

[0027] Continuously observe through the values of the CCD infrared camera and the optical power meter until the position of the cursor observed on the display screen of the CCD infrared camera is at the center of the field of view and the values of the optical power meters on each reach the expected power, then the installation and adjustment are qualified and the installation and adjustment are completed;

[0028] S5. Adjust the optical path direction of the beam splitter by grinding the beam splitter chassis until the coaxiality error of the entire optical path meets the requirements;

[0029] So far, the optical path optical installation and adjustment of the laser communication terminal are completed.

[0030] Furthermore, in the step of adjusting the optical path direction of the beam splitter by grinding the beam splitter chassis, observe the light spot on the display screen of the CCD infrared camera to adjust the position of the beam splitter. The coaxiality error of a single optical path is not greater than 3 μrad, and the coaxiality error of the entire optical path is not greater than 5 μrad.

[0031] Furthermore, in the step of adjusting the optical path direction of the beam splitter by grinding the beam splitter chassis, when adjusting the position of the beam splitter, proceed as follows: adjust the coaxiality of each optical path separately, judge whether the position of the beam splitter is aligned with the receiver by observing the value of the optical power meter, and grind the chassis of the beam splitter according to the value until the optical path is aligned, ensuring that the coaxiality error of the optical path is not greater than 3 μrad; after the coaxiality of all single optical paths meets the requirements, adjust the position of each beam splitter to ensure that the coaxiality error of the entire optical path is not greater than 5 μrad.

[0032] Further, in the step of individually adjusting the coaxiality of each optical path, start the adjustment from the first beam splitter that enters the next beam splitter through the first refractive optical path or enters the next beam splitter after being reflected by the PZT.

[0033] Further, in the step of individually adjusting the coaxiality of each optical path, after the adjustment of all the beam splitters through which all the refractive optical paths enter the next beam splitter or enter the next beam splitter after being reflected by the PZT is completed, there is no order requirement for the adjustment of the remaining beam splitters.

[0034] The beneficial technical effects achieved by the present invention are as follows:

[0035] The installation conditions of each optical component in the optical path of the laser communication terminal can be visually adjusted. Compared with the method of repeatedly assembling, adjusting and testing the whole machine to determine whether the optical components are accurately installed and whether the optical path is deviated, the time spent on assembly and adjustment is greatly shortened, the labor consumption for the optical path assembly and adjustment of the communication terminal is significantly reduced, the complexity of the optical path test of the communication terminal is simplified, the reliability of the whole assembly and adjustment process is effectively improved, the problems of cumbersome operation and long time consumption in the optical path assembly and adjustment process of the laser communication terminal in the prior art are solved, and it has outstanding substantive features and remarkable progress.

[0036] Other features and advantages of the present invention will be described in the subsequent description, and part of them will become obvious from the description or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written description, claims and drawings. Description of the Drawings

[0037] Figure 1 is a schematic diagram of the external structure of the optical path optical assembly and adjustment device of one specific embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of the optical structure and optical path propagation principle of the optical path of the laser communication terminal of the present invention;

[0039] Reference numerals: 1, laser communication terminal; 3, laser terminal light output hole; 101, first beam splitter; 102, second beam splitter; 103, third beam splitter; 104, fourth beam splitter; 201, first PZT; 202, second PZT; 301, first receiver; 302, second receiver; 303, third receiver; 401, CCD infrared camera; 500, optical pen fixed housing; 501, infrared optical pen; 502, positioning light output port; 503, optical pen positioning seat; 504, adjustment intermediate seat; 505, adapter seat; 506, positioning light input port; 601, first optical power meter; 602, second optical power meter; 603, third optical power meter. Detailed Embodiments

[0040] The following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. Specific details such as specific system structures, models, technical parameters, etc. proposed in the following description are only explanations made for better understanding of the specific embodiments, rather than limitations, and should not affect the protection scope of the present invention. In addition, the content that should be known and understood by those skilled in the art will not be elaborated here.

[0041] As Figures 1-2 shown, a specific embodiment of an optical path optical alignment device for a laser communication terminal is applicable to an optical adjustment system where the laser propagation direction is parallel to the optical platform, and includes a light pen fixing shell 500, an infrared light pen 501, a light pen positioning seat 503, an adjustment intermediate seat 504, and an adapter seat 505. A positioning light output port 502 is provided on the light pen fixing shell 500, and a positioning light input port 506 is provided on the light pen positioning seat 503.

[0042] In this specific embodiment, the laser communication terminal 1 has a housing-encapsulated structure, the bottom mounting surface is a plane, the laser terminal light input hole (not shown in the figure) is provided at the top, and its axis is perpendicular to the bottom mounting surface. There are four laser terminal light output holes 3, which are respectively provided on the side wall of the laser communication terminal 1 along the direction parallel to the bottom mounting surface in the axial direction.

[0043] In this specific embodiment, a first beam splitter 101, a second beam splitter 102, a third beam splitter 103, a fourth beam splitter 104, a first PZT 201, a second PZT 202, a first receiver 301, a second receiver 302, a third receiver 303, a CCD infrared camera 401, a first optical power meter 601, a second optical power meter 602, and a third optical power meter 603 are provided inside the laser communication terminal 1. After the infrared laser enters the laser communication terminal 1 through the laser terminal light input hole, it sequentially passes through the first PZT 201, the first beam splitter 101, the second beam splitter 102, the second PZT 202, and the fourth beam splitter 104 and then hits the second receiver 302. The second receiver 302 is connected to the second optical power meter 602 at the rear end.

[0044] In this specific embodiment, the first beam splitter 101, the second beam splitter 102, and the fourth beam splitter 104 are energy beam splitters, which can split the light beam into two beams according to the energy ratio, one is the reflected light and the other is the direct light. When the infrared laser passes through the first beam splitter 101, the direct light part is directed to the second beam splitter 102, and the reflected light part is directed to the CCD infrared camera 401. When the infrared laser passes through the second beam splitter 102, the reflected light part is directed to the second PZT 202, and the direct light part is directed to the third beam splitter 103, and after reflection, it hits the first receiver 301. The back end of the first receiver 301 is connected to the first optical power meter 601. When the infrared laser passes through the fourth beam splitter 104, the direct light part is directed to the second receiver 302, and the reflected light part hits the third receiver 303. The back end of the third receiver 303 is connected to the third optical power meter 603. In this specific embodiment, the CCD infrared camera 401 used is an InGaAs short-wave infrared uncooled focal plane detection camera, which can display the received laser spot on the display screen in real time. In this specific embodiment, the PZT, that is, the fast steering mirror, uses a piezoelectric ceramic electromagnetic galvanometer for light path reflection. The receiver is the communication receiver of the laser communication terminal 1, which can collect the received parallel light and transmit it in the optical fiber. The function of the optical power meter is to detect the optical signal power entering the communication receiver in real time. By observing the optical power value received by the optical power meter, it can be judged whether the light beam split by the beam splitter and entering the receiver is aligned with the receiver. By observing the values of the three optical power meters and the spot on the display screen of the CCD infrared camera 401, the alignment of the beam splitters in the rear optical path can be confirmed.

[0045] It should be noted that the internal structures of the laser communication terminals 1 are not all the same, but the principle remains unchanged. Based on the technical solution described in this specific embodiment, the optical path optical alignment device should be adaptively modified according to the actual situation to adapt to the structures of different models of laser communication terminals 1. Such modifications can be made by those skilled in the art in combination with common general knowledge and should not be regarded as involving creative work.

[0046] The infrared light pen 501 is detachably installed in the light pen fixing case 500. A positioning light outlet 502 is provided at the end of the light pen fixing case 500. The infrared light pen 501 is used to emit a parallel light beam with high direction stability. In this specific embodiment, the emitted light is infrared laser. The infrared laser emitted by the infrared light pen 501 is emitted through the positioning light outlet 502. The light pen fixing case 500 has two functions: one is to fix the infrared light pen 501 and reliably fix it to the light pen positioning seat 503; the other is to adjust the direction of the infrared light pen 501 so that the emitted infrared laser is coaxial with the positioning light inlet 506 provided on the light pen positioning seat 503. The light pen fixing case 500 and the light pen positioning seat 503 are threadedly connected, and can also be connected by snap connection or other fixing methods. The adapter seat 505 is detachably installed on the top of the laser communication terminal 1. The adjustment intermediate seat 504 is detachably connected to the light pen positioning seat 503 and the adapter seat 505 respectively. Through holes are provided on both the adapter seat 505 and the adjustment intermediate seat 504, and the size and position of the through holes are determined according to the size and position of the laser terminal light inlet hole and the positioning light inlet 506. The function of the adjustment intermediate seat 504 is to adjust the relative positions of the light pen positioning seat 503 and the adapter seat 505, and improve the adaptability of the optical path optical alignment device. The parallel infrared laser emitted by the infrared light pen 501 sequentially passes through the positioning light outlet 502, the positioning light inlet 506, the adjustment intermediate seat 504, the adapter seat 505, and enters the laser communication terminal 1 from the laser terminal light inlet hole.

[0047] Based on the same concept, the present invention also provides an optical path optical alignment method for a laser communication terminal. The beam splitter is aligned by using the above optical path optical alignment device, and the steps are as follows:

[0048] S1. Establish a Cartesian coordinate system on the bottom surface of the rear optical path. Through theoretical calculation, calculate the positions of the components in the coordinate axes of the bottom plane.

[0049] S2. Use an autocollimator to accurately mark the angles and positions where each beam splitter is to be installed.

[0050] In this specific embodiment, there are four beam splitters, including the first beam splitter 101, the second beam splitter 102, the third beam splitter 103, and the fourth beam splitter 104.

[0051] S3. Install each beam splitter at the marked positions.

[0052] S4. Turn on the infrared light pen 501, and observe whether the alignment is qualified through the numerical values of the CCD infrared camera 401 and the optical power meter.

[0053] S4.1. Turn on the infrared light pen 501 to emit infrared laser light. Observe the position of the cursor on the display screen of the CCD infrared camera 401. If the cursor is at the center of the field of view, the position of the first beam splitter 101 is correct; if it is not at the center of the field of view, the position of the first beam splitter 101 is inaccurate, and adjust the position of the beam splitter according to step S5.

[0054] S4.2. Observe the power meter values on each power meter. If the power of all power meters reaches the expected power, the alignment and adjustment are qualified, and the alignment and adjustment are ended; if the expected power is not reached, the position of the beam splitter where the optical path after refraction enters the corresponding power meter without any deflection is inaccurate, and adjust the position of the beam splitter according to step S5.

[0055] In this specific embodiment, if the power of the first power meter 601 reaches the expected power, the position of the third beam splitter 101 is accurate; if the expected power is not reached, adjust the position of the beam splitter according to step S5.

[0056] When the power of the second power meter 602 or the third power meter 603 does not reach the expected power, the adjustment idea is the same, and it will not be elaborated here.

[0057] Until the position of the cursor observed on the display screen of the CCD infrared camera 401 is at the center of the field of view, and the power meter values observed on each power meter reach the expected power, the alignment and adjustment are qualified, and the alignment and adjustment are ended.

[0058] S5. Adjust the optical path direction of the beam splitter by grinding the beam splitter chassis.

[0059] S5.1. In this specific embodiment, adjust the position of the first beam splitter by observing the light spot on the display screen of the CCD infrared camera 401, and grind the chassis of the first beam splitter 101 according to the position where the light spot deviates from the center of the field of view, so that the coaxiality error of the single optical path is not greater than 3 μrad.

[0060] S5.2. Observe the value of the second power meter 602, and judge whether the position of the second beam splitter 102 is aligned with the second receiver 302 by observing the value of the second power meter 602, and grind the chassis of the second beam splitter 102 according to the value until the optical path is aligned, ensuring that the coaxiality error of the optical path is not greater than 3 μrad.

[0061] S5.3. Observe the value of the first power meter 601, and judge whether the position of the third beam splitter 103 is aligned with the first receiver 301 by observing the value of the first power meter 601, and grind the chassis of the third beam splitter 103 according to the value until the optical path is aligned, ensuring that the coaxiality error of the optical path is not greater than 3 μrad.

[0062] S5.4. Observe the value of the third optical power meter 603, and judge whether the position of the fourth beam splitter 104 is aligned with the third receiver 303 by observing the value of the third optical power meter 603. Grind the chassis of the fourth beam splitter 104 according to the value until the optical path is aligned, ensuring that the coaxiality error of the optical path is not greater than 3 μrad.

[0063] S5.5. By adjusting the positions of the first beam splitter 101, the second beam splitter 102, the third beam splitter 103, and the fourth beam splitter 104, ensure that the coaxiality error of the entire optical path is not greater than 5 μrad.

[0064] Thus, the optical alignment of the laser communication terminal is completed.

[0065] It should be noted that the order of steps S5.1 and S5.3 can be interchanged without affecting the final result.

[0066] The beneficial technical effects obtained by this specific embodiment are as follows:

[0067] The installation conditions of each optical component in the optical path of the laser communication terminal can be adjusted intuitively. Compared with the method of repeatedly assembling, adjusting, and testing the whole machine to determine whether the optical components are installed accurately and whether the optical path is deviated, the time spent on adjustment is greatly shortened, the labor consumption for the optical path adjustment of the communication terminal is significantly reduced, the complexity of the optical path test of the communication terminal is simplified, the reliability of the entire adjustment process is effectively improved, and the problems of cumbersome operation and long time consumption in the optical path adjustment process of the laser communication terminal in the prior art are solved.

[0068] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical path optical alignment device for a laser communication terminal, characterized in that, It includes a light pen fixing shell (500), an infrared light pen (501), a light pen positioning seat (503) and an adapter seat (505). A positioning light outlet (502) is provided on the light pen fixing shell (500), and a positioning light inlet (506) is provided on the light pen positioning seat (503). The infrared light pen (501) is detachably installed in the light pen fixing shell (500), and the light pen fixing shell (500) and the light pen positioning seat (503) are detachably fixed; the adapter seat (505) is detachably installed on the top of the laser communication terminal, the light pen positioning seat (503) is detachably connected to the adapter seat (505), and a through hole is provided on the adapter seat (505); the parallel infrared laser emitted by the infrared light pen (501) passes through the positioning light outlet (502), the positioning light inlet (506) and the adapter seat (505), and enters the laser communication terminal through the light inlet hole of the laser terminal. The light pen fixing shell (500) is used to fix the infrared light pen (501) and adjust the direction of the infrared light pen (501) so that the emitted infrared laser is coaxial with the positioning light inlet (506). The bottom mounting surface of the laser communication terminal is a plane. The light inlet hole of the laser terminal is provided at the top, and its axis is perpendicular to the bottom mounting surface. The light outlet hole of the laser terminal is provided on the side wall of the laser communication terminal along the direction parallel to the bottom mounting surface in the axial direction. Inside the laser communication terminal, there are beam splitters, PZT, receivers, a CCD infrared camera and a optical power meter. There are at least two beam splitters. After the infrared laser emitted by the infrared light pen (501) enters the laser communication terminal through the light inlet hole of the laser terminal, the optical path is changed by the beam splitters and PZT and then hits the receivers and the CCD infrared camera. The optical power meter is connected to the rear end of the receiver. The CCD infrared camera is used to display the received laser spot on the display screen in real time; the PZT is used for the reflection of the optical path. The receiver serves as the communication receiver of the laser communication terminal and is used to collect the received parallel light into the optical fiber for transmission; the optical power meter is used to detect the optical signal power entering the communication receiver in real time. Whether the beam split by the beam splitter and entering the receiver is aligned with the receiver is judged by observing the optical power value received by the optical power meter; the alignment of the beam splitter is confirmed by observing the value of the optical power meter and the spot on the display screen of the CCD infrared camera.

2. The optical path optical alignment device according to claim 1, characterized in that, The optical path optical alignment device further includes an adjustment intermediate seat (504). The adjustment intermediate seat (504) is detachably connected to the light pen fixing shell (500) and the adapter seat (505) respectively. A through hole is provided on the adjustment intermediate seat (504) for the infrared laser to pass through.

3. The optical path optical alignment device according to claim 2, wherein The CCD infrared camera adopts an InGaAs short-wave infrared uncooled focal plane detection camera.

4. The optical path optical alignment device according to claim 3, characterized in that, The PZT adopts an electromagnetic vibrating mirror of piezoelectric ceramics.

5. The optical path optical alignment device according to claim 3, characterized in that A threaded connection is adopted between the light pen fixing shell (500) and the light pen positioning seat (503).

6. An optical path optical alignment method for a laser communication terminal, characterized in that, Using the optical path optical alignment device described in any one of claims 1 to 5, the following steps are included: S1. Establish a Cartesian coordinate system on the bottom surface of the rear optical path, and calculate the positions of the components in the coordinate axes of the bottom plane through theoretical calculation. S2. Precisely mark the angles and positions for installing each beam splitter using an autocollimator; S3. Install each beam splitter at the marked positions; S4. Turn on the infrared light pen (501), and observe whether the installation and adjustment are qualified through the values of the CCD infrared camera and the optical power meter; S4.

1. Turn on the infrared light pen (501) to emit infrared laser. Observe the position of the cursor on the display screen of the CCD infrared camera. If the cursor is at the center of the field of view, it means that the optical path generated after refraction does not deflect at all and the position of the beam splitter entering the infrared camera is correct. If it is not at the center of the field of view, it means that the position of the above beam splitter is inaccurate, and adjust the position of the beam splitter according to step S5; S4.

2. Observe the values on each optical power meter. If the power of each optical power meter reaches the expected power, the installation and adjustment are qualified, and the installation and adjustment are completed. If the expected power is not reached, it means that the position of the beam splitter where the optical path generated after refraction does not deflect at all and enters the corresponding optical power meter is inaccurate, and adjust the position of the beam splitter according to step S5; Continuously observe through the values of the CCD infrared camera and the optical power meter until the position of the cursor observed on the display screen of the CCD infrared camera is at the center of the field of view, and the values of the optical power meters observed on each optical power meter reach the expected power, then the installation and adjustment are qualified, and the installation and adjustment are completed; S5. Adjust the optical path direction of the beam splitter by grinding the beam splitter chassis until the coaxiality error of the entire optical path meets the requirements; So far, the optical path optical installation and adjustment of the laser communication terminal are completed.

7. The optical path optical alignment method according to claim 6, wherein, In the step of adjusting the optical path direction of the beam splitter by grinding the beam splitter chassis, observe the light spot on the display screen of the CCD infrared camera to adjust the position of the beam splitter. The coaxiality error of a single optical path is not greater than 3 μrad, and the coaxiality error of the entire optical path is not greater than 5 μrad.

8. The optical path optical alignment method according to claim 7, characterized in that, In the step of adjusting the optical path direction of the beam splitter by grinding the beam splitter chassis, when adjusting the position of the beam splitter, proceed as follows: adjust the coaxiality of each optical path separately, judge whether the position of the beam splitter is aligned with the receiver by observing the value of the optical power meter, and grind the chassis of the beam splitter according to the value until the optical path is aligned, ensuring that the coaxiality error of the optical path is not greater than 3 μrad; after the coaxiality of all single optical paths meets the requirements, adjust the positions of each beam splitter to ensure that the coaxiality error of the entire optical path is not greater than 5 μrad.

9. The optical path optical alignment method according to claim 8, characterized in that In the step of adjusting the coaxiality of each optical path separately, start the adjustment from the beam splitter where the first refracted optical path enters the next beam splitter or after being reflected by the PZT and enters the next beam splitter.

10. The optical path optical alignment method according to claim 9, characterized in that, In the step of adjusting the coaxiality of each optical path separately, according to the optical propagation path, sequentially adjust the beam splitters where the refracted optical path enters the next beam splitter or after being reflected by the PZT and enters the next beam splitter until the refracted optical paths of the remaining beam splitters all directly reach the receiver or the infrared camera. There is no order requirement for the adjustment of the remaining beam splitters.

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