CN107655659A - Laser communication terminal vacuum test system and test method thereof - Google Patents

Abstract

The invention relates to a laser communication terminal vacuum test system and a test method thereof, including a divergence angle test system, a power test system and a wave phase difference test system; the laser communication terminal is adjusted so that the laser communication terminal points to and aligns with a collimator; the collimator receives The beam emitted by the laser communication terminal is converged and imaged on the photocoupler of the divergence angle test module; the laser communication terminal is adjusted so that the laser communication terminal emits a beam coaxial with the beam reduction system, and the emitted beam passes through the beam reduction system to form a beam reduction Parallel beams, narrowed parallel beams are split by the first beam splitter and transmitted to the power meter and the second beam splitter respectively. The second beam splitter splits the beam again and then the first Hartmann wavefront sensor and the second Hart Mambo front sensor reception. It can complete the thermal vacuum test of the single-ended laser communication terminal, verify the stability of the laser communication terminal during the high and low temperature vacuum process, and is an indispensable test system for the thermal vacuum test of the laser communication terminal.

Description

A vacuum test system and test method for a laser communication terminal

technical field

The invention belongs to the field of optical detection, and relates to a vacuum test system and a test method for a laser communication terminal, in particular to a test system and a test method for parameters such as divergence angle, wave phase difference, and emission power of a space laser communication terminal under vacuum conditions.

Background technique

Compared with traditional microwave space communication, laser communication, especially space laser communication, has the advantages of high speed, confidentiality, anti-interference and small size. With the development of space remote sensing technology, various payloads will obtain a large amount of space detection data, which needs to be transmitted to the ground in real time for analysis by relevant technical personnel. At present, the microwave bandwidth commonly used on satellites is about 100 megabytes, which is close to the theoretical limit of microwave communication, while the actual optical fiber laser communication transmission rate is as high as 40G/s, which has been practically applied at present. , DWDM) and other optical amplification technologies can also achieve higher transmission rates. The Baiji-level fiber laser communication system on the ground has been commercialized, so the use of lasers for communication will greatly reduce the pressure on data transmission. With the successful experiment of 5.65G/s space laser communication terminal (Laser Communication Terminal, LCT), dozens of gigabit rate space LCTs abroad are also under research and planning, which fully proves the advantages of laser communication in practical applications , so using laser as a medium for communication can solve the communication bandwidth bottleneck problem very well.

As a payload, the space laser communication system must be strictly tested for its main technical indicators no matter after the development is completed or before launch. In a thermal vacuum environment, evaluating the key indicators of the space laser communication system has become the top priority in the environmental test of the space laser communication system.

Since the information transmission of the space laser communication terminal requires at least one terminal to complete, and the test system required for the dual-terminal docking information transmission test is very complicated, it is very difficult to complete the dual-terminal docking test in the thermal vacuum test. Therefore, vacuum The key indicators of the single-ended space laser communication terminal are tested under these conditions.

The key indicators of a single-ended laser communication terminal include wave phase difference, divergence angle, and transmission power. How to complete the measurement of the above three indicators under thermal vacuum conditions is a difficult problem in verifying the thermal vacuum stability of a single-ended laser communication terminal.

Contents of the invention

The purpose of the present invention is to provide a laser communication terminal vacuum testing system and its testing method, to realize the testing of key indicators such as wave phase difference, divergence angle and transmission power under thermal vacuum conditions of a single-ended laser communication terminal.

The technical solution of the present invention is to provide a vacuum test system for laser communication terminals, which is special in that it includes a divergence angle test system, a power test system and a wave phase difference test system;

The launch angle of the laser communication terminal can be adjusted;

The above-mentioned divergence angle testing system includes a collimator 1 and a divergence angle testing module 2 arranged sequentially along one outgoing optical path of the laser communication terminal; the above-mentioned divergence angle testing module 2 includes a three-dimensional translation platform and a photocoupler arranged on the three-dimensional translation platform;

The above-mentioned laser communication terminal emits a light beam coaxial with the collimator 1; the above-mentioned collimator 1 receives the light beam emitted by the laser communication terminal, and converges the image on the photocoupler of the divergence angle test module 2;

The above-mentioned laser communication terminal and collimator 1 are located in a vacuum environment;

The above-mentioned power test system includes a beam shrinking system 6 arranged sequentially along the other outgoing optical path of the laser communication terminal, a first beam splitter 8 and a power meter 12 located in one outgoing optical path of the first beam splitter 8;

The above-mentioned wave phase difference testing system includes a second beam splitter 9 located in the other outgoing light path of the first beam splitter 8, and a second Hartmann wavefront sensor 11 and the first Hartmann wavefront sensor 11 respectively located in the outgoing light path of the second beam splitter 9. Terman wavefront sensor 10;

The above-mentioned laser communication terminal emits a beam coaxial with the beam reduction system 6, and the emitted beam passes through the beam reduction system 6 to form a reduced beam parallel beam, which is split by the first beam splitter 8 and transmitted to the power meter 12 and the second On the beam splitter 9 , the second beam splitter 9 splits the beam again and receives it by the first Hartmann wavefront sensor 10 and the second Hartmann wavefront sensor 11 .

Preferably, the test system also includes a vacuum tank 3 with an optical window 5. The above-mentioned laser communication terminal 4 is located in the vacuum tank 3, and the outgoing light of the laser communication terminal enters the beam reduction system 6 through the optical window 5;

The above-mentioned collimator 1 is fixedly connected with the vacuum tank 3, and the collimator 1 and the vacuum tank 3 form a closed vacuum space in which a vacuum environment can be simulated.

Preferably, in order to improve the measurement accuracy of the divergence angle, the above-mentioned collimator 1 is a parabolic reflective collimator with a long focal length axis. It is generally considered that a collimator with a focal length greater than 10 m is a long focal length collimator.

Preferably, the photosensitive surface of the divergence angle testing module 2 is located at the focal plane of the collimator 1 .

Preferably, the photosensitive device in the above-mentioned divergence angle test module 2 includes at least one CCD or CMOS device with a spectral range of 800nm to 1600nm; the above-mentioned divergence angle test module 2 also includes an attenuation sheet group positioned at the front end of the photosensitive device. The attenuation film set adjusts the energy entering the photosensitive device.

Preferably, the above-mentioned attenuation system 6 is composed of off-axis parabolic mirrors and eyepieces 7 sequentially arranged along the optical path, and the calculation formula of the attenuation magnification Γ is shown in formula (1);

Wherein: L is the exit pupil diameter of the laser communication terminal 4;

a is the diameter of the inscribed circle of the target surface of the two Hartmann wavefront sensors.

Preferably, the characteristic wavelengths of the first Hartmann wavefront sensor 10 and the second Hartmann wavefront sensor 11 match the characteristic wavelength of space laser communication.

Preferably, the above-mentioned vacuum tank 3 has a diameter of 3 m and a length of 5 m, and the internal vacuum degree can reach 1×10 ^-6 Pa;

The above-mentioned optical window 5 is a Φ500mm diameter window, and the material of the window glass is quartz or microcrystalline;

The above-mentioned collimator 1 is an off-axis parabolic reflective collimator with a focal length of 30 m and a diameter of Φ1 m;

The characteristic wavelengths of the above-mentioned first Hartmann wavefront sensor 10 are 808nm and 830nm, and the characteristic wavelengths of the above-mentioned second Hartmann wavefront sensor 11 are 1541nm and 1550nm;

The off-axis parabolic mirror of the attenuator system 6 is a Φ250mm off-axis parabolic mirror;

The above parameters are not limited to the data given.

Preferably, the aforementioned power meter 12 is an integrating sphere power meter 12 with a wavelength response range of 800nm-1700nm and a dynamic range of 0.01W-10W.

The present invention also provides a laser communication terminal vacuum test method based on the above-mentioned laser communication terminal vacuum test system, including the following steps:

Step 1: Simultaneously evacuate the interior of the vacuum tank and the collimator, and start the performance test of the laser communication terminal after the vacuum degree reaches within 1×10 ^-5 Pa;

Step 2: Adjust the laser communication terminal so that the laser communication terminal points to and aligns with the collimator;

Step 3: Select the attenuation sheet group, install it into the divergence angle test module, and turn on the laser communication terminal to emit the laser beam;

Step 4: The divergence angle test module adjusts the exposure time according to the formed spot image;

Step 5: The divergence angle test module continuously collects six images, calculates the spot diameter D _i corresponding to different images, and calculates the spot diameter at the focal plane according to formula (2) The unit is mm, and the divergence angle θ corresponding to different wavelengths is calculated according to formula (3), and the unit is rad;

Step 6: Adjust the angle of the laser communication terminal so that the laser communication terminal points to and aligns with the beam reduction system;

Step 7: Select two sets of attenuation sheets, install them into the front end of the first Hartmann wavefront sensor and the second Hartmann wavefront sensor respectively, and turn on the laser communication terminal to emit the laser beam;

Step 8: The power meter measures the outgoing power P ₂ , and calculates the emitted optical power P ₁ of the laser communication terminal according to formula (4);

Wherein, τ ₁ is the transmittance of the reduced beam system; τ ₂ is the reflectivity of the first beam splitter;

Step 9: The first Hartmann wavefront sensor receives the 808nm laser, and obtains the wave phase difference of the outgoing beam by adjusting its attitude; the second Hartmann wavefront sensor receives the 1541nm laser, and obtains the wave phase difference of the outgoing beam by adjusting its attitude.

The beneficial effects of the present invention are:

1. The present invention can complete the thermal vacuum test of a single-ended laser communication terminal, verify the stability of the laser communication terminal in the process of vacuum high and low temperature, and is an indispensable test system for the thermal vacuum test of the laser communication terminal;

2. The laser communication terminal vacuum test system of the present invention uses two-way splitting, which can simultaneously obtain the wave phase difference and transmission power of the laser communication terminal. The test process is stable and reliable, and the test efficiency can be greatly improved. It is very suitable for engineering testing In the middle application, the system puts the tested modules outside the vacuum environment, which is convenient for the subsequent expansion of other index tests, and its transformation function is very powerful;

3. The present invention uses a long focal length collimator to measure the divergence angle, and the divergence angle of the laser communication terminal is on the micro-arc scale, which can greatly improve the measurement accuracy of the divergence angle;

4. The present invention uses the design of the beam shrinking system and the beam splitter, which can simultaneously measure the wave phase difference of two wavelengths of the laser communication terminal, and can realize the simultaneous measurement of the wave phase difference and output power of the laser communication terminal. The system structure is stable and repeatable. , to meet the test requirements of thermal vacuum test.

Description of drawings

Fig. 1 is a schematic structural view of a divergence angle test module of a laser communication terminal vacuum test system provided by the present invention;

Fig. 2 is a schematic structural diagram of a wave phase difference and emission optical power test module of a laser communication terminal vacuum test system provided by the present invention;

3 is an enlarged view of a wave phase difference and emitted light power test module of a laser communication terminal vacuum test system provided by the present invention;

In the figure: 1-collimator; 2-divergence angle test module; 3-vacuum tank; 4-laser communication terminal; 5-optical window; 6-beam reduction system; 7-eyepiece; 8-first beam splitter; 9 - second beam splitter; 10 - first Hartmann wavefront sensor; 11 - second Hartmann wavefront sensor; 12 - power meter.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

It can be seen from Figures 1 and 2 that the test system of this embodiment includes a vacuum tank 3 for placing the laser communication terminal 4. The size of the vacuum tank 3 is 3m in diameter and 5m in length, and the internal vacuum degree can reach 1×10 ^-6 Pa; one side of the vacuum tank 3 has a quartz or microcrystalline optical window 5 capable of transmitting light, and the diameter of the optical window 5 is Φ500 mm; the direction of the outgoing light of the laser communication terminal 4 is adjustable.

It also includes a divergence angle test system, a power test system and a wave phase difference test system located in the outgoing light path of the laser communication terminal 4 .

The divergence angle test system includes a collimator 1 and a divergence angle test module 2 arranged along the optical path. The collimator 1 and the laser communication terminal 4 are in the same closed space, which can simulate a vacuum environment. The focal length and aperture are large, and it is difficult for the optical window 5 glass to achieve a diameter of Φ1m. Therefore, the collimator 1 and the vacuum tank 3 are connected together to form a closed space, which is convenient for simulating the vacuum environment; the divergence angle test module 2 and the power Both the test system and the wave phase difference test system are located outside the vacuum environment, and it is convenient to adjust the position; in this embodiment, the collimator 1 is an off-axis parabolic reflective collimator 1 with a focal length of 30 m and a diameter of Φ1 m. Not limited to this parameter; the photosensitive surface of the divergence angle test module 2 is located at the focal plane of the collimator 1, and the photosensitive device in the divergence angle test module 2 is a CCD or CMOS device with a spectral range of 800nm to 1600nm. It is also possible to meet the needs of the entire test spectrum range by replacing devices with different wavelength ranges; the front end of the photosensitive device of the divergence angle module can be added with an attenuating film group, and the energy entering the photosensitive device can be adjusted by adding attenuating film groups with different attenuation ratios.

The light beam emitted by the laser communication terminal 4 is coaxial with the collimator 1 , and the collimator 1 receives the light beam emitted by the laser communication terminal 4 and is imaged on the divergence angle test module 2 after convergence.

The power test system includes a beam shrinking system 6 arranged along the optical path, a first beam splitter 8 and a power meter 12. In this embodiment, the power meter 12 is located in the reflected light path of the first beam splitter 8. In other embodiments, the power meter 12 It can also be located in the transmission light path of the first beam splitter 8, as long as the power meter 12 and the wave phase difference testing system are respectively located in different light paths of the first beam splitter 8. The beam reduction system 6 is composed of a Φ250mm off-axis parabolic mirror and an eyepiece 7, and the calculation formula of the beam reduction magnification Γ is shown in formula (1);

Where: L is the exit pupil diameter of the laser communication terminal 4; a is the target surface size of the Hartmann wavefront sensor;

The power meter 12 is an integrating sphere power meter 12 with a wavelength response range of 800nm to 1700nm and a dynamic range of 0.01W to 10W;

The wave phase difference test system includes a second beam splitter 9 located in the transmission light path of the first beam splitter 8, a first Hartmann wavefront sensor 10 located in the transmission light path of the second beam splitter 9, and a first Hartmann wavefront sensor 10 located in the transmission light path of the second beam splitter 9. The second Hartmann wavefront sensor 11, in other embodiments the first Hartmann wavefront sensor 10 and the second Hartmann wavefront sensor 11 positions can be interchanged; The first Hartmann wavefront sensor 10 The characteristic wavelengths are 808nm and 830nm, and the characteristic wavelengths of the second Hartmann wavefront sensor 11 are 1541nm and 1550nm; these wavelengths are the characteristic wavelengths of space laser communication, but not limited to these wavelengths;

After the laser communication terminal 4 adjusts the azimuth angle, the emission beam is coaxial with the beam reduction system 6, and the emission beam passes through the optical window 5 and the beam reduction system 6 to form a parallel beam reduction beam, which is split by the first beam splitter 8 and transmitted to the power On the meter 12 and the second beam splitter 9, after being split by the second beam splitter 9, the light is received by the first Hartmann wavefront sensor 10 and the second Hartmann wavefront sensor 11 respectively.

At the same time, the present invention also provides a vacuum test method based on the laser communication terminal 4 as described above, the method includes the following steps:

1) The inside of the vacuum tank 3 and the collimator 1 are evacuated at the same time, and after the vacuum degree reaches within 1×10 ^-5 Pa, the performance test of the laser communication terminal is started;

2) The laser communication terminal 4 adjusts the pointing to align with the collimator 1;

3) According to the calculation in advance, select a suitable attenuator to assemble into the divergence angle test module 2, and turn on the laser communication terminal 4 to emit the laser beam;

4) The divergence angle test module 2 adjusts a suitable exposure time according to the formed spot image, generally making the imaged gray value not exceed 80% of the total number of quantized digits;

5) Continuously collect 6 images, calculate the spot diameter D _i corresponding to different images according to the program, and calculate according to formula (2) The divergence angle θ of different wavelengths is calculated by formula (3).

Where: θ is the signal light divergence angle, unit: rad;

is the spot diameter at the focal plane, unit: mm;

6) The laser communication terminal 4 adjusts the pointing and aligns with the beam reduction system 6;

7) According to the calculation in advance, select a suitable attenuator to assemble into the front end of the Hartmann wavefront sensor, and open the laser communication terminal 4 to emit the laser beam;

8) The power meter 12 measures the outgoing power P ₂ , and calculates the transmitted optical power P ₁ of the laser communication terminal 4 according to formula (4);

Where: P ₁ is the optical power emitted by the laser communication terminal 4;

P ₂ is the output power measured by the power meter 12;

τ ₁ is the transmittance of the beam reduction system 6; τ ₂ is the reflectivity of the first beam splitter 8;

9) The first Hartmann wavefront sensor 10 receives the 808nm laser, and obtains the wave phase difference of the outgoing beam by adjusting its attitude. The second Hartmann wavefront sensor 11 receives the 1541nm laser, and obtains the wave phase difference of the outgoing beam by adjusting its attitude.

The laser communication terminal vacuum test system of the present invention can meet the measurement of the main optical parameters of the single-ended laser communication terminal, and verify the stability of the laser communication terminal in the process of vacuum high and low temperature, which is indispensable in the thermal vacuum test process of the laser communication terminal test system.

The laser communication terminal vacuum test system of the present invention uses two beam splitters, which can simultaneously obtain the wave phase difference and emission power of the laser communication terminal. The test process is stable and reliable, and can greatly improve the test efficiency. It is very suitable for application in engineering testing. , the system puts the tested modules out of the vacuum environment, which facilitates the subsequent expansion of other index tests, and its transformation function is very powerful.

The laser communication terminal vacuum test system of the present invention selects a collimator with a longer focal length to measure the divergence angle, which can greatly improve the measurement accuracy of the divergence angle.

Claims (10)

1. A kind of 1. laser communication terminal vacuum test system, it is characterised in that：Including angle of divergence test system, power test system And ripple difference test system；

   Laser communication terminal transmission angle can be adjusted；

   The angle of divergence test system is included along the laser communication terminal parallel light tube (1) that emitting light path is set gradually all the way and hair Dissipate angle test module (2)；The angle of divergence test module (2) includes D translation platform and the photoelectricity being arranged on D translation platform Coupler；

   The laser communication terminal transmission light beam coaxial with parallel light tube (1)；It is whole that the parallel light tube (1) receives laser communication The light beam of transmitting is held, and converges and is imaged on the photoelectrical coupler of angle of divergence test module (2)；

   The laser communication terminal is located in vacuum environment with parallel light tube (1)；

   Shrink beam system (6) that the power test system includes setting gradually along laser communication terminal another way emitting light path, the One spectroscope (8) and the power meter (12) in the first spectroscope (8) all the way emitting light path；

   Ripple difference test system include the second spectroscope (9) being located in the first spectroscope (8) another way emitting light path and The second Hartmann wave front sensor (11) and first Hartmann's wavefront sensing being located at respectively in the second spectroscope (9) emitting light path Device (10)；

   The laser communication terminal transmission light beam coaxial with shrink beam system (6), transmitting light beam are formed after shrink beam system (6) Shrink beam collimated light beam, shrink beam collimated light beam are divided through the first spectroscope (8), are transmitted separately to power meter (12) and the second spectroscope (9) on, the second spectroscope (9) light beam is divided again after by the first Hartmann wave front sensor (10) and the second Hartmann Wavefront sensor (11) receives.
2. A kind of 2. laser communication terminal vacuum test system according to claim 1, it is characterised in that：Also include that there is light The vacuum tank (3) of window (5) is learned, the laser communication terminal (4) is located in vacuum tank (3), the emergent light of laser communication terminal Shrink beam system (6) is incident to by optical window (5)；

   The parallel light tube (1) is connected with vacuum tank (3), and parallel light tube (1) forms closed vacuum space with vacuum tank (3).
3. A kind of 3. laser communication terminal vacuum test system according to claim 2, it is characterised in that：The parallel light tube (1) it is long-focus off-axis parabolic collimator.
4. A kind of 4. laser communication terminal vacuum test system according to claim 3, it is characterised in that：The angle of divergence is surveyed The photosurface of die trial block (2) is located at the focal plane of parallel light tube (1).
5. A kind of 5. laser communication terminal vacuum test system according to claim 4, it is characterised in that：The angle of divergence is surveyed Sensor devices in die trial block (2) include the CCD or cmos device that at least one spectral region is 800nm~1600nm；It is described Angle of divergence test module (2) also includes the attenuator group positioned at sensor devices front end, by the decay for adding differential declines multiplying power Piece group is adjusted into the energy of sensor devices.
6. 6. according to a kind of any described laser communication terminal vacuum test systems of claim 1-5, it is characterised in that：The contracting Beam system (6) is made up of the off axis paraboloidal mirror and eyepiece (7) set gradually along light path, shrink beam multiplying power Γ calculation formula such as public affairs Shown in formula (1)；

   <mrow> <mi>&amp;Gamma;</mi> <mo>=</mo> <mfrac> <mi>L</mi> <mi>a</mi> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

   Wherein：L is the exit pupil diameter of laser communication terminal (4)；

   A is the inscribed circle diameter of the target surface of two Hartmann wave front sensors.
7. A kind of 7. laser communication terminal vacuum test system according to claim 6, it is characterised in that：First Hart Graceful Wavefront sensor (10) and the characteristic wavelength of the second Hartmann wave front sensor (11) and the characteristic wavelength of laser space communication Matching.
8. A kind of 8. laser communication terminal vacuum test system according to claim 7, it is characterised in that：

   A diameter of 3m, a length of 5m of the vacuum tank (3), internal vacuum is up to 1 × 10^-6Pa；

   The optical window (5) is Φ 500mm diameter windows, and the material of window glass is quartz or crystallite；

   The parallel light tube (1) is 30m focal lengths, the off-axis parabolic collimator of Φ 1m bores；

   The characteristic wavelength of first Hartmann wave front sensor (10) is 808nm, 830nm, and the second Hartmann wavefront passes The characteristic wavelength of sensor (11) is 1541nm, 1550nm；

   The off axis paraboloidal mirror of shrink beam system (6) is Φ 250mm off axis paraboloidal mirrors.
9. A kind of 9. laser communication terminal vacuum test system according to claim 7, it is characterised in that：The power meter (12) it is integrating sphere type power meter, wavelength response range is 800nm~1700nm, dynamic range 0.01W~10W.
10. 10. a kind of laser communication based on a kind of any described laser communication terminal vacuum test systems of claim 1-9 is whole Hold vacuum test method, it is characterised in that comprise the following steps：

    Step 1：For vacuum tank with being vacuumized inside parallel light tube simultaneously, vacuum reaches 1 × 10^-5After within Pa, start laser and lead to Believe terminal capabilities test；

    Step 2：Adjust laser communication terminal so that laser communication terminal is pointed to and is directed at parallel light tube；

    Step 3：Attenuator group is selected, is fitted into angle of divergence test module, opens laser communication terminal transmission laser beam；

    Step 4：Angle of divergence test module adjusts the time for exposure according to institute into light spot image；

    Step 5：The width image of angle of divergence test module continuous acquisition six, calculate spot diameter D corresponding to different images_i, according to public affairs Formula (2) calculates spot diameter at focal planeUnit is mm, the angle of divergence θ according to corresponding to formula (3) calculates different wave length, unit For rad；

    <mrow> <mover> <mi>D</mi> <mo>&amp;OverBar;</mo> </mover> <mo>=</mo> <mfrac> <mrow> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mn>6</mn> </munderover> <mrow> <mo>(</mo> <msub> <mi>D</mi> <mn>1</mn> </msub> <mo>+</mo> <msub> <mi>D</mi> <mn>2</mn> </msub> <mo>+</mo> <mn>...</mn> <mo>+</mo> <msub> <mi>D</mi> <mn>6</mn> </msub> <mo>)</mo> </mrow> </mrow> <mn>6</mn> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

    <mrow> <mi>&amp;theta;</mi> <mo>=</mo> <mfrac> <mover> <mi>D</mi> <mo>&amp;OverBar;</mo> </mover> <mi>f</mi> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow>

    Step 6：Adjust the angle of laser communication terminal so that laser communication terminal is pointed to and is directed at shrink beam system；

    Step 7：Two groups of attenuator groups are selected, are respectively charged into the first Hartmann wave front sensor and second Hartmann's wavefront sensing Device front end, open laser communication terminal transmission laser beam；

    Step 8：Power meter measurement outgoing power P₂, laser communication terminal transmission luminous power P is calculated according to formula (4)₁；

    <mrow> <msub> <mi>P</mi> <mn>1</mn> </msub> <mo>=</mo> <mfrac> <msub> <mi>P</mi> <mn>2</mn> </msub> <mrow> <msub> <mi>&amp;tau;</mi> <mn>1</mn> </msub> <mo>&amp;times;</mo> <msub> <mi>&amp;tau;</mi> <mn>2</mn> </msub> </mrow> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>4</mn> <mo>)</mo> </mrow> </mrow>

    Wherein, τ₁For the transmitance of shrink beam system；τ₂For first spectroscopical reflectivity；

    Step 9：First Hartmann wave front sensor receives 808nm laser, and outgoing beam ripple phase is obtained by adjusting its posture Difference, the second Hartmann wave front sensor receive 1541nm laser, and outgoing beam ripple difference is obtained by adjusting its posture.