CN116990982A

CN116990982A - Space optical transmission device for laser communication and adjustment method

Info

Publication number: CN116990982A
Application number: CN202311243363.3A
Authority: CN
Inventors: 永强; 徐伟; 谢晓光; 李小冬; 谭嘉恒
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2023-09-26
Filing date: 2023-09-26
Publication date: 2023-11-03
Anticipated expiration: 2043-09-26
Also published as: CN116990982B

Abstract

The invention relates to a space optical transmission device and an adjustment method for laser communication, belongs to the technical field of optical signal rotation transmission, and solves the technical problems of unstable mechanical structure, complex detection and adjustment process, insufficient resource utilization and low reliability in the laser communication space optical transmission process. The invention transfers the pointing angle reference and the radial displacement reference of the collimator to be measured to the plane mirror and the mounting and adjusting collimator respectively through reasonable application to the collimator to be measured, the mounting and adjusting collimator, the laser, the circulator, the reference prism, the plane mirror, the optical power meter, the theodolite, the six-dimensional adjusting frame and the like, thereby avoiding the influence of the mutual coupling of the pointing angle error and the radial displacement error of the collimator on the optical power meter reading and realizing the high-precision measurement of the optical path of the alignment collimator. The device has the characteristics of compact structure, high assembly and adjustment precision, simple optical detection, strong vibration resistance and the like.

Description

Space optical transmission device for laser communication and adjustment method

Technical Field

The invention relates to the technical field of optical signal rotation transmission, in particular to a space optical transmission device for laser communication and an adjustment method.

Background

When the two ends of the optical fiber continuously rotate in the transmission process, the conventional laser optical fiber generates larger optical loss or possibly causes the optical fiber to be damaged. If the optical fiber slip ring is selected, additional resistance moment can be generated for rotary motion, and the probe can be worn after long-time friction, so that the service life and the reliability of the system are influenced. The spatial light transmission device for laser communication generally comprises a transmitting end and a receiving end, wherein a laser signal in an optical fiber can be converted into spatial light through a transmitting end collimator, and the receiving end collimator couples the spatial light into the optical fiber, so that signal transmission is completed. In the transmission process of the laser communication system, the light paths of the transmitting end collimator and the receiving end collimator of the space light transmission device are aligned, so that the goal of efficient laser transmission can be achieved.

Devices generally used in the field of aerospace or other high reliability often concentrate on higher reliability, and a space optical transmission device for laser communication is designed with a backup optical path, so that when the loss of a main optical path becomes large or a fault occurs, the device can be switched into the backup optical path, thereby further improving the reliability of the system and reducing the maintenance cost. If the conventional method obviously cannot ensure that four sets of collimators for receiving and transmitting two optical paths of a main optical path and a backup optical path are mutually shielded, the collimator of one optical path can influence the other optical path.

Because the adjustment accuracy of the collimator has a larger influence on the coupling efficiency of the receiving and transmitting optical path, and the pointing angle error and the radial displacement error of the collimator are mutually coupled and influence the optical power counting, the conventional adjustment method for observing the optical power counting cannot judge whether the optical power loss is caused by the pointing angle error or the radial displacement error of the collimator.

Disclosure of Invention

The invention provides a space optical transmission device and an adjustment method for laser communication, which aims to solve the technical problems that in the prior art, a collimator pointing angle error and a radial displacement error are mutually coupled and an optical power loss source cannot be judged in the space optical transmission process of laser communication.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a spatial light transmission device for laser communication, comprising: a transmitting end and a receiving end;

the transmitting end and/or the receiving end respectively comprise: the device comprises a main collimator, a reference prism, a main collimator fixing frame, a backup collimator fixing frame and a backup collimator;

the main collimator and the main collimator fixing frame are fixed on the fixing frame through a third screw; the backup collimator and the backup collimator fixing frame are fixed on the fixing frame through first screws; the fixing frame is fixed on the transmitting end and/or the connecting piece of the receiving end through a second screw;

The main collimator adjusts the light path direction and position of the collimator by adjusting a first light path adjusting gasket and a first radial adjusting jackscrew; the backup collimator adjusts the light path direction and position of the collimator through adjusting a second light path adjusting gasket and a second radial adjusting jackscrew; the fixing frame adjusts the light path direction and position of the transmitting end or the receiving end through adjusting a third light path adjusting gasket and a third radial adjusting jackscrew;

the switching between the main part and the backup light path is realized by the translation of a 45-degree reflecting mirror through the cooperation of a ball screw, a guide rail sliding block and a sliding block connecting piece.

In the technical scheme, the spatial light transmission device is provided with the mechanism control unit, the mechanism control unit accurately judges the position of the 45-degree reflecting mirror through detecting feedback of the grating ruler, and high-precision closed-loop control of the position of the 45-degree reflecting mirror is realized through control of a motor, and the position repetition precision is within +/-0.1 mm.

A method of tuning a spatial light transmission device for laser communication, the spatial light transmission device for laser communication comprising: a transmitting end and a receiving end;

the switching between the main part and the backup light path is realized by the high-precision matching of the ball screw, the guide rail slide block and the slide block connecting piece and the translation of the 45-degree reflecting mirror;

the method for adjusting comprises the following steps:

step 1: splitting the adjustment reference by matching a main collimator and/or a backup collimator to be tested, an adjustment collimator, a laser, a circulator, a reference prism, a fourth plane mirror, an optical power meter, a theodolite and a six-dimensional adjusting frame;

Step 2: transferring the pointing angle reference of the light path of the primary collimator and/or the backup collimator to a fourth plane mirror;

step 3: and transferring the radial displacement reference of the primary collimator and/or the backup collimator light path to the adjustment collimator to realize adjustment of the collimator light path.

In the above technical solution, the method for adjusting the reference prism includes the following steps:

placing a fixing frame on an air bearing table, wiping a mechanical reference surface by dust-free cloth, installing a reference prism, screwing a screw, tightly attaching a first plane mirror to the mechanical reference surface, and adjusting the view field of the theodolite to enable the view field of the theodolite to be capable of simultaneously aiming at the reference prism and the first plane mirror;

and turning on an auto-collimation lamp of the theodolite, adjusting the focal length of the theodolite to infinity, observing the cross silk image reflected by the reference prism 2 and the first plane mirror, grinding the reference prism base correspondingly according to the positions of the two cross silk images, and repeating the steps to finally enable the cross silk image reflected by the reference prism and the first plane mirror to coincide, wherein the error of the corresponding surface of the reference prism is better than +/-0.001 degrees with the first plane mirror.

In the above technical solution, the method for adjusting the 45 ° reflector includes the following steps:

Placing a fixed frame on an air bearing table, wiping a mechanical reference surface by dust-free cloth, placing a second plane mirror on the mounting end surface of the backup collimator, and adjusting the view field of the theodolite to enable the theodolite to aim at a 45-degree reflecting mirror and a third plane mirror which is tightly attached to the mechanical reference surface at the same time;

and turning on an auto-collimation lamp of the theodolite, adjusting the focal length of the theodolite to infinity, observing the cross silk images reflected by the 45-degree reflecting mirror, the second plane mirror and the third plane mirror, and grinding the reflecting mirror gaskets according to the positions of the two cross silk images, and finally enabling the two cross silk images to coincide by repeating the steps, wherein the second plane mirror is parallel to the normal line of the third plane mirror after being reflected by the 45-degree reflecting mirror, and the error is better than +/-0.001 degrees.

In the above technical solution, the collimator pointing angle reference transfer method includes the following steps:

placing a fixing frame on an air floatation table, cutting out a 45-degree reflecting mirror to enable a main collimator to be in a working state, connecting the main collimator with a circulator, a laser and an optical power meter, opening the laser and the optical power meter, and placing a fourth plane mirror fixed on a two-dimensional adjusting table at the front end, wherein the fourth plane mirror adjusts an azimuth angle and a pitch angle through the two-dimensional adjusting table;

The laser path sent by the primary collimator coincides with the laser path received after being reflected by the fourth plane mirror, at the moment, the optical power loss is minimum, and the optical power count reaches the maximum value;

and (3) starting from the position with the maximum optical power counting number, respectively adjusting the azimuth angle and the pitch angle of the fourth plane mirror vertically and horizontally to perform verification, and observing the optical power counting number: if the optical power loss value after deflection is asymmetric, continuously adjusting the azimuth angle and the pitch angle of the fourth plane mirror according to the result; when the difference of the optical power loss values after deflection in the four directions is not more than 1dB, the maximum value point of the optical power count at the moment is considered as the symmetrical center point of the optical path of the main collimator, so that the pointing angle reference of the main collimator is transferred to a fourth plane mirror for measurement by a theodolite;

adjusting the view field of the theodolite to enable the view field of the theodolite to aim at the reference prism and the fourth plane mirror at the same time, turning on an auto-collimation lamp of the theodolite, adjusting the focal length of the theodolite to infinity, observing cross images reflected back by the reference prism and the fourth plane mirror, grinding a main collimator adjusting gasket according to the positions of the two cross images, repeating the steps to finally enable the two cross images to coincide, and enabling the normal line of the fourth plane mirror to be parallel to the normal line of the reference prism when the optical path of the main collimator is perpendicular to the fourth plane mirror, wherein the error is better than +/-10'.

In the above technical solution, the collimator radial displacement reference transfer method includes the following steps:

placing a fixing frame on an air floatation table, cutting out a 45-degree reflecting mirror to enable a main light path to be in a working state, placing an adjusting collimator at a position which is a certain distance away from the main collimator at the front part of a transmitting end and/or a receiving end, fixing the adjusting collimator with a six-dimensional adjusting frame, placing a prism and a dial indicator on the six-dimensional adjusting frame, and measuring the pointing angle change and radial displacement change of the adjusting collimator through the theodolite aiming prism and the reading of an observation dial indicator so as to avoid errors caused by the empty return of the six-dimensional adjusting frame;

the method comprises the steps of connecting a main collimator fiber to a laser or an optical power meter, connecting an adjusting collimator fiber to the optical power meter or the laser, fixing the main collimator by using jackscrews around, adjusting the light path direction and radial displacement of the adjusting collimator through a six-dimensional adjusting frame to enable the optical power meter to reach the maximum value, then respectively adjusting the azimuth angle and pitch angle of the adjusting collimator to be respectively deflected 3' from left to right up to down from the position with the maximum optical power meter, verifying the radial displacement of the adjusting collimator to be respectively deflected by 0.4mm from left to right up to down, and observing the optical power meter display: if the corresponding optical power loss values after deflection and offset are asymmetric, continuously adjusting the optical path direction and radial displacement of the installed and adjusted collimator according to the result; when the difference of the corresponding optical power loss values after the four-direction angle deflection and the four-direction displacement deflection is not more than 1dB, the maximum value point of the optical power count at the moment is the symmetrical center point of the collimator light path, the assembly collimator light path is overlapped with the main collimator light path, the radial displacement reference of the main collimator is transferred to the assembly collimator, and the position is taken as the position origin of the assembly collimator;

Maintaining a fixed frame and an adjusting collimator, cutting in a 45-degree reflecting mirror to enable a backup light path to work, connecting the backup collimator with a laser or an optical power meter, enabling the optical power meter to reach the maximum value by adjusting jackscrews around the backup collimator, then starting from the position, respectively adjusting the radial displacement of the adjusting collimator vertically from left to right by 0.4mm for verification, and observing the optical power meter to count: if the optical power loss value after the offset is asymmetric, continuously adjusting jackscrews around the backup collimator after the installed collimator is adjusted back to the original point of the position according to the result; when the difference of the optical power loss values after the displacement and the offset in the four directions is not more than 1dB, the maximum value point of the optical power count at the moment is considered to be the symmetrical center point of the collimator optical path, and the backup collimator optical path is overlapped with the adjustment collimator optical path and the main collimator optical path after being reflected by the 45-degree reflecting mirror, so that the error is better than +/-0.05 mm.

In the above technical solution, the method for adjusting the direction of the light path of the transmitting end includes the following steps:

the method comprises the steps of installing a space light transmission unit transmitting end on a rotary joint rotor shell, adjusting the positions of 2 theodolites to enable the respective fields of view of the 2 theodolites to respectively aim at two adjacent surfaces of a transmitting end reference prism, turning on auto-collimation lamps of the 2 theodolites, and adjusting the focal length of the 2 theodolites to infinity to respectively aim at two adjacent surfaces of the transmitting end reference prism;

The third light path adjusting gasket of the transmitting end is polished to enable the pitching axis display number of the corresponding surface of the aiming reference prism of 2 theodolites to be within 90+/-0.001 degrees.

In the above technical solution, the method for adjusting the direction of the light path of the receiving end includes the following steps:

the receiving end of the space light transmission unit is arranged on the stator shaft of the rotary joint, the positions of the 2 theodolites are adjusted to enable the respective fields of view to respectively aim at two adjacent surfaces of the reference prism of the receiving end, the auto-collimation lamps of the 2 theodolites are turned on, and the focal length of the 2 theodolites is adjusted to infinity to respectively aim at two adjacent surfaces of the reference prism of the receiving end;

the pitching axis indication number of the 2 theodolites after aiming at the corresponding surface of the reference prism is simultaneously within 90+/-0.001 degrees through repairing and grinding the light path adjusting gasket of the receiving end.

In the above technical solution, the method for adjusting radial displacement of the transmitting end and the receiving end includes the following steps:

the transmitting end primary collimator is connected with the laser, the receiving end primary collimator is connected with the optical power meter, and the 45-degree reflecting mirrors of the transmitting end and the receiving end are adjusted to be in a cut-out state, so that the transmitting end primary collimator and the receiving end primary collimator work;

rotating the rotary joint rotor shell at a constant speed, adjusting radial jackscrews at the transmitting end and radial jackscrews at the receiving end to ensure that the indication number of the optical power meter reaches the error requirement range in the rotating process of the rotary joint, finding out the position with the minimum space optical loss, and screwing up the mounting screw;

And sequentially measuring four working modes of the transmitting end primary collimator aiming at the receiving end primary collimator, the transmitting end primary collimator aiming at the receiving end backup collimator, the transmitting end backup collimator aiming at the receiving end primary collimator and the transmitting end backup collimator aiming at the receiving end backup collimator, recording the optical power loss under each mode, and repeating the steps to readjust the radial displacement of the transmitting end and the receiving end if the optical power loss does not meet the requirement until the optical power loss meets the design requirement, wherein an optical path of the transmitting end and an optical path of the receiving end coincide with a rotation central shaft.

The invention has the following beneficial effects:

according to the space light transmission device and the adjustment method for laser communication, the split of the adjustment reference is realized through reasonable application of a laser, a circulator, a plane mirror, an optical power meter, a theodolite, a six-dimensional adjustment frame and the like, the pointing angle reference of the optical path of the collimator to be tested is transferred to the plane mirror, the radial displacement reference is transferred to the adjustment collimator, the influence of mutual coupling of the pointing angle error and the radial displacement error of the collimator on the optical power meter reading is avoided, and therefore the adjustment precision of the optical path of the collimator is improved.

The invention solves the problem that the signal cannot be effectively transmitted when the two ends of the optical fiber continuously rotate during the traditional laser communication signal transmission, and provides a high-precision adjustment method, which is used for respectively transferring the pointing angle reference and the radial displacement reference of the collimator to be tested to the plane mirror and the adjustment collimator, avoiding the influence of the mutual coupling of the pointing angle error and the radial displacement error of the collimator on the optical power meter display, and the invention provides a space optical transmission device for laser communication, which has the characteristics of compact structure, high equipment adjustment precision, simple optical detection, strong vibration resistance and the like.

Drawings

The invention is described in further detail below with reference to the drawings and the detailed description.

Fig. 1 is a schematic diagram showing the mechanical structure layout of a spatial light transmission device for laser communication according to the present invention.

Fig. 2 is a schematic diagram of an optical path switching principle of the spatial light transmission device for laser communication according to the present invention.

Fig. 3 is a schematic diagram of optical path switching control logic of the spatial light transmission device for laser communication according to the present invention.

Fig. 4 is a schematic diagram of a reference prism assembly of a spatial light transmission device for laser communication according to the present invention.

Fig. 5 is a schematic diagram of 45 ° mirror adjustment of a spatial light transmission device for laser communication according to the present invention.

Fig. 6 is a flow chart of a method for transferring pointing angle references of a spatial light transmission device for laser communication according to the present invention.

Fig. 7 is a schematic diagram of the collimator optical path pointing adjustment of the spatial light transmission device for laser communication according to the present invention.

Fig. 8 is a flow chart of a radial displacement reference transfer method of the spatial light transmission device for laser communication according to the present invention.

Fig. 9 is a schematic diagram of primary backup collimator radial displacement adjustment for a spatial light transmission device for laser communication according to the present invention.

Fig. 10 is a schematic diagram of the optical path pointing adjustment of the transmitting end of the spatial light transmission device for laser communication according to the present invention.

Reference numerals in the drawings denote:

1-a primary collimator; 2-a reference prism; 3-a first radial adjustment jackscrew; 4-a third screw; 5-a first optical path adjustment spacer; 6-a main collimator fixing frame; 7-fixing frames; 8-ball screw; 9-a guide rail slide block; 10-a slider connection; 11-a second screw; 12-a third radial adjustment jackscrew; 13-a third optical path adjustment spacer; 14-a second radial adjustment jackscrew; 15-a first screw; 16-backup collimator mount; 17-backup collimator; 18-a second optical path adjustment spacer; 19-45 DEG reflecting mirror; 20-connecting piece; 21-a circulator; 22-a laser; 23-optical power meter; 24-a fourth plane mirror; 25-installing and adjusting a collimator; 26-a mechanical datum; 27-a first plane mirror; 28-a second planar mirror; 29-a third plane mirror; 30-rotary joint rotor shell.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1 to 10, the spatial light transmission device for laser communication of the present invention includes: a transmitting end and a receiving end; the transmitting end and/or the receiving end respectively comprise: a primary collimator 1, a reference prism 2, a primary collimator holder 6, a holder 7, a backup collimator holder 16 and a backup collimator 17.

The main collimator 1 and the main collimator fixing frame 6 are fixed on the fixing frame 7 through a third screw 4; the backup collimator 17 and the backup collimator fixing frame 16 are fixed on the fixing frame 7 through first screws 15; the fixing frame 7 is fixed on the connecting piece 20 of the transmitting end and/or the receiving end through the second screw 11;

the main collimator 1 adjusts the light path direction and position of the collimator by adjusting a first light path adjusting gasket 5 and a first radial adjusting jackscrew 3; the backup collimator 17 adjusts the collimator light path direction and position by adjusting the second light path adjusting gasket 18 and the second radial adjusting jackscrew 14; the fixing frame 7 adjusts the light path direction and position of a transmitting end or a receiving end through adjusting a third light path adjusting gasket 13 and a third radial adjusting jackscrew 12;

the switching between the main part and the backup light path is realized by the high-precision matching of the ball screw 8, the guide rail sliding block 9 and the sliding block connecting piece 10 and the translation of the 45-degree reflecting mirror 19. The 45 ° mirror 19 is coated with a reflective film having a small absorptivity in the spatial optical communication spectrum.

The main collimator 1, the main collimator fixing frame 6, the fixing frame 7, the backup collimator fixing frame 16 and the backup collimator 17 are respectively made of the following materials: any one of a hard aluminum alloy, a titanium alloy or a 40Cr material.

The spatial light transmission device is provided with a mechanism control unit, the mechanism control unit accurately judges the position of the 45-degree reflecting mirror 19 through feedback of the detection grating ruler, and high-precision closed-loop control of the position of the 45-degree reflecting mirror 19 is realized through control of a motor, and the position repetition precision is within +/-0.1 mm. The fundamental frequency of the spatial light transmission device reaches more than 200 Hz.

The invention relates to a method for adjusting a space optical transmission device for laser communication, which comprises the following steps:

step 1: the main collimator 1 and/or the backup collimator 17, the adjusting collimator 25, the laser 22, the circulator 21, the reference prism 2, the fourth plane mirror 24, the optical power meter 23, the theodolite and the six-dimensional adjusting frame to be tested are matched to split the adjusting reference; the primary collimator 1, the backup collimator 17, the laser 22 and the optical power meter 23 are connected with the circulator 21; the fourth plane mirror 24 and the alignment collimator 25 are respectively fixed on the six-dimensional adjusting frame.

Step 2: transferring the reference pointing angle of the optical path of the primary collimator 1 and/or the backup collimator 17 to a fourth plane mirror 24;

step 3: the radial displacement reference of the optical path of the primary collimator 1 and/or the backup collimator 17 is transferred to the adjusting collimator 25, so that the high-precision adjustment of the optical path of the collimator is realized. The radial displacement reference of the optical path of the primary collimator 1 is transferred to the adjustment collimator 25, the adjustment collimator 25 is kept still, the operation is switched to the backup collimator 17, the radial displacement of the backup collimator 17 is adjusted through a jackscrew, and when the indication of the optical power meter 23 reaches the maximum value, the optical path of the backup collimator 17 coincides with the optical path of the adjustment collimator 25, so that the high-precision adjustment of the radial displacement of the optical path of the collimator is realized. Specifically, the azimuth angle and the pitch angle of the fourth plane mirror 24 are adjusted by using the six-dimensional adjusting frame, when the laser path emitted by the primary collimator 1 coincides with the laser path received after being reflected by the fourth plane mirror 24, the optical power loss is minimum, and the indication number of the optical power meter 23 reaches the maximum.

The present invention will be described in further detail with reference to the accompanying drawings.

In a first aspect, the present invention provides a spatial light transmission device for laser communication, as shown in fig. 1-10, where the spatial light transmission device is composed of two parts, namely, a transmitting end and a receiving end, and the internal structures of the spatial light transmission device are identical and only slightly different from the external interfaces, as shown in fig. 1, and the main collimator 1, the backup collimator 17, the 45 ° reflector 19, the guide rail slider 9, the ball screw 8, and the like are assembled on a high-rigidity and high-strength titanium alloy fixing frame with high precision through reasonable structural layout.

In this embodiment, as shown in fig. 2, the schematic diagram of optical path switching of the spatial light transmission device is that the geometric center axis (i.e. the rotation axis) of the transmitting end (or receiving end) primary collimator 1 and the geometric center axis (i.e. the rotation axis) of the transmitting end (or receiving end) fixing frame 7 coincide, the optical path included angle between the transmitting end (or receiving end) primary collimator 1 and the backup collimator 17 is 90 °, and the included angle between the 45 ° mirror surface of the switching mechanism slider connector 10 and the primary and backup optical paths is 45 °. The laser light emitted (received) by the backup collimator 17 is reflected by the 45 ° reflecting mirror 19 and then coincides with the geometric center axis of the transmitting end (or receiving end) fixing frame 7 (i.e. coincides with the main optical path).

In the embodiment, a switching mechanism is further provided, and the switching mechanism is specifically formed by driving a worm by a motor so as to drive a worm wheel, wherein the worm wheel moves the 45-degree reflecting mirror 19 through the ball screw 8, and in addition, the 45-degree reflecting mirror 19 limits other degrees of freedom except the horizontal movement through a high-precision guide rail and a sliding block, so that the stability in the switching process reaches 5'; in addition, the position of the 45-degree reflecting mirror 19 is accurately positioned through the self-locking property of the worm gear and the worm, so that the aim of switching the main backup light path is fulfilled.

In this embodiment, a mechanism control unit is further provided, which accurately determines the position of the 45 ° reflecting mirror 19 by detecting feedback of the grating ruler, and performs forward rotation, reverse rotation and maintenance by using a driving motor to realize high-precision closed-loop control of the position of the 45 ° reflecting mirror 19, where the repetition precision of the position of the linear motion is within ±0.1mm, and receives parameters of the driving motor and the grating ruler by using an RS422 bus, so as to complete analysis and execution of the instruction, and transmit the instruction to an external single machine of the previous system, and an optical path switching control logic diagram is shown in fig. 3.

The space light transmission device is designed under the assistance of a computer through modal analysis, vibration analysis, thermal deformation analysis and the like, and the applicability of the product is further enhanced through limit design, vacuum grease coating and the like.

The 45 mirror 19 of the present invention is gold plated (or other reflective film having a small absorptivity in the spatial optical communication spectrum).

In the invention, the light path pointing adjustment of the primary collimator and/or the backup collimator is realized by repairing and grinding the dihedral angle of the first light path adjusting gasket 5 and/or the second light path adjusting gasket 18, and is fixed with the transmitting end/receiving end fixing frame 7 by uniformly distributing the third screws 4 and/or the first screws 15.

In the invention, the radial adjustment of the collimator light path adjusts the two-dimensional plane motion of the collimator light path through the front and back movement of the first radial adjustment jackscrews 3 and/or the second radial adjustment jackscrews 14 around the collimator light path so as to coincide with the rotation axis.

In the invention, the whole light path of the transmitting end (or receiving end) is adjusted by modifying the dihedral angle of the third light path adjusting gasket 13 of the transmitting end (or receiving end) so that the light path of the transmitting end (or receiving end) is parallel to the rotation axis (or other required light paths).

In the invention, the two-dimensional plane motion of the light path of the transmitting end (or the receiving end) is adjusted by the forward and backward movement of the third radial adjusting jackscrew 12 around the transmitting end (or the receiving end) so as to be coincided with the rotation axis.

The fundamental frequency of the equipment can reach more than 200Hz, and the equipment can still meet the use requirement after environmental tests such as space-level vibration tests, impact tests, thermal vacuum tests and the like.

The main mechanical structures of the invention are made of high-rigidity hard aluminum alloy, titanium alloy, 40Cr and other materials.

In a second aspect, the present invention further provides a high-precision adjustment method for a collimator, which is suitable for the spatial light transmission device provided in the first aspect, and by splitting the pointing angle reference and the radial displacement reference of the collimator, the influence of mutual coupling of the pointing angle error and the radial displacement error of the collimator on the optical power counting is avoided.

In the invention, before the pointing angles and radial displacements of the primary collimator 1 and the backup collimator 17 at the transmitting end (or receiving end) are adjusted, the assembly of a reference prism at the transmitting end (or receiving end) and the adjustment of a 45-degree reflecting mirror 19 are completed.

In the invention, the internal structures of the transmitting end and the receiving end of the space optical transmission device are identical and only slightly different from the external interface, so that the adjustment methods of the transmitting end and the receiving end are identical.

After the transmitting end and the receiving end are assembled and adjusted respectively, the transmitting end, the receiving end and the rotary joint are assembled and adjusted in a butt joint mode, the preparation work is carried out before the butt joint assembly and adjustment, the light path of the transmitting end points to the assembly and adjustment, and the light path of the receiving end points to the assembly and the radial displacement adjustment of the transmitting end and the receiving end.

In this embodiment, the method for adjusting the reference prism 2 includes the following steps:

1. as shown in fig. 4, the transmitting end (or receiving end) fixing frame 7 is placed on an air floating platform, a dust-free cloth is used for wiping a mechanical reference surface 26, a reference prism 2 is installed, screws are screwed, a first plane mirror 27 is tightly attached to the mechanical reference surface 26, and the view field of the theodolite is adjusted so that the view field can aim at the reference prism 2 and the first plane mirror 27 at the same time;

2. the auto-collimation lamp of the theodolite is turned on, the focal length of the theodolite is adjusted to infinity, the cross silk image reflected by the reference prism 2 and the first plane mirror 27 is observed, the base of the reference prism 2 is correspondingly ground according to the positions of the two cross silk images, the step is repeated to finally enable the cross silk image reflected by the reference prism 2 and the first plane mirror 27 to coincide, and then the corresponding surface of the reference prism 2 is parallel to the first plane mirror 27, namely the mechanical reference surface 26, and the error is better than +/-0.001 degrees.

In this embodiment, the method for adjusting the 45 ° mirror 19 includes the following steps:

1. as shown in fig. 5, the transmitting end (or receiving end) fixing frame 7 is placed on an air floating platform, the mechanical reference surface 26 is wiped by dust-free cloth, a second plane mirror 28 is placed on the mounting end surface of the backup collimator 17, and the view field of the theodolite is adjusted to aim at the 45-degree reflecting mirror 19 and a third plane mirror 29 which is closely attached to the mechanical reference surface 26 at the same time;

2. The auto-collimation lamp of the theodolite is turned on, the focal length of the theodolite is adjusted to infinity, the cross silk images reflected by the 45-degree reflecting mirror 19, the second plane mirror 28 and the third plane mirror 29 are observed, and the two cross silk images are finally overlapped by repeating the steps according to the corresponding grinding mirror gaskets of the positions of the two cross silk images, so that the normal line of the second plane mirror 28, namely the mounting end surface of the backup collimator 17, is parallel to the normal line of the third plane mirror 29, namely the mechanical reference surface 26 after being reflected by the 45-degree reflecting mirror 19, and the error is better than +/-0.001 degrees.

In this embodiment, a flow chart of the collimator pointing angle reference transfer method is shown in fig. 6, and includes the following steps:

1. taking the transmitting end primary collimator 1 as an example, a transmitting end (or receiving end) fixing frame 7 is placed on an air bearing table, a 45-degree reflecting mirror 19 is cut out to enable a primary light path to be in a working state, the primary collimator 1 is connected with a circulator 21, a laser 22 and an optical power meter 23, the laser 22 and the optical power meter 23 are opened, a fourth plane mirror 24 fixed on a two-dimensional adjusting table is placed at the front end, and the fourth plane mirror 24 can adjust azimuth angle and pitch angle through the two-dimensional adjusting table;

2. since the collimator can be used as a transmitting and receiving device of laser at the same time after being connected with the circulator 21, when the optical path of the primary collimator 1 is vertical to the fourth plane mirror 24, namely, the optical path of the laser emitted by the primary collimator 1 coincides with the optical path of the laser received after being reflected by the fourth plane mirror 24, at the moment, the optical power loss is minimum, and the indication number of the optical power meter 23 reaches the maximum;

3. The azimuth angle and the pitch angle of the fourth plane mirror 24 are adjusted to maximize the indication of the optical power meter 23, and since the optical power loss of the main collimator 1 near the optical path superposition is low, the maximum indication position of the optical power meter 23 is not a point but a section, the optical path of the main collimator 1 cannot be judged to be parallel to the normal line of the fourth plane mirror 24 only by the maximum indication of the optical power meter 23, and the indication of the optical power meter 23 is verified by adjusting the deflection 3' of the azimuth angle and the pitch angle of the fourth plane mirror 24 from the maximum indication position of the optical power meter 23 respectively left, right, up and down. If the optical power loss value after deflection is asymmetric, continuing to adjust the azimuth angle and the pitch angle of the fourth plane mirror 24 according to the result; when the difference of the optical power loss values after the deflection in the four directions is not more than 1dB, the maximum value point of the indication of the optical power meter 23 at this time can be considered as the symmetrical center point of the optical path of the primary collimator 1, namely, the optical path of the primary collimator 1 is perpendicular to the fourth plane mirror 24, so that the pointing angle reference of the primary collimator 1 is transferred to the fourth plane mirror 24 for measurement by a theodolite;

4. adjusting the view field of the theodolite to enable the theodolite to aim at the reference prism 2 and the fourth plane mirror 24 at the same time, turning on an auto-collimation lamp of the theodolite, adjusting the focal length of the theodolite to infinity, observing the cross silk images reflected by the reference prism 2 and the fourth plane mirror 24, grinding a main collimator 1 adjusting pad according to the positions of the two cross silk images, repeating the steps to finally enable the two cross silk images to coincide, and enabling the normal line of the fourth plane mirror 24 to be parallel to the normal line of the reference prism 2 when the optical path of the main collimator 1 is perpendicular to the fourth plane mirror 24, wherein the error is better than +/-10'.

In this embodiment, the collimator pointing angle reference transfer method is not affected by the collimator radial displacement error, and the difference between the adjustment of the pointing angle of the optical path of the backup collimator 17 and the adjustment of the pointing angle of the optical path of the primary collimator 1 is that the 45 ° mirror 19 is in the cut-in state, i.e. the backup optical path works.

In this embodiment, the collimator radial displacement reference transfer method is shown in fig. 8, and includes the following steps:

1. as shown in fig. 9, a transmitting end (or receiving end) fixing frame 7 is placed on an air floatation table, a 45-degree reflecting mirror 19 is cut out, a main optical path is in a working state, a receiving (transmitting) adjusting collimator 25 for testing is placed at the position, which is 213mm away from the length of the main collimator 1, at the front part of the transmitting end (or receiving end), the adjusting collimator 25 is fixed with a six-dimensional adjusting frame, a prism and a dial indicator are placed on the six-dimensional adjusting frame, and the pointing angle change and the radial displacement change of the adjusting collimator 25 can be accurately measured through the sighting prism of the theodolite and the reading of the dial indicator, so that errors caused by the empty back of the six-dimensional adjusting frame are avoided;

2. the optical fiber of the main collimator 1 at the transmitting end (receiving end) is connected to the laser 22 (or the optical power meter 23), the optical fiber of the receiving (transmitting) adjusting collimator 25 is connected to the optical power meter 23 (or the laser 22), the main collimator 1 is fixed by using the peripheral jackscrews, the optical path direction and the radial displacement of the adjusting collimator 25 are adjusted by the six-dimensional adjusting frame to ensure that the indication of the optical power meter 23 reaches the maximum value, and then starting from the position with the maximum indication of the optical power meter 23, respectively adjusting the azimuth angle and the pitch angle of the collimator 25 vertically and horizontally to deflect 3', and respectively adjusting the radial displacement of the collimator 25 vertically and horizontally to deflect 0.4mm to verify, and observing the indication of the optical power meter 23. If the corresponding optical power loss values after deflection and offset are asymmetric, continuously adjusting the optical path direction and radial displacement of the adjusting collimator 25 according to the result; when the difference between the corresponding optical power loss values after the four-direction angle deflection and the four-direction displacement deflection is not more than 1dB, the maximum value point of the indication of the optical power meter 23 at the moment can be considered as the symmetrical center point of the collimator optical path, namely the optical path of the alignment collimator 25 is overlapped with the optical path of the main collimator 1, so that the radial displacement reference of the main collimator 1 is transferred to the alignment collimator 25, and the position is taken as the position origin of the alignment collimator 25;

3. The transmitting end (or receiving end) fixing frame 7 and the adjusting collimator 25 are kept still, a 45-degree reflecting mirror 19 is cut into to enable a backup light path to work, the backup collimator 17 is connected to a laser 22 (an optical power meter 23) through optical fibers, the indication of the optical power meter 23 reaches the maximum value through adjusting jackscrews around the backup collimator 17, and then, from the position, the radial displacement of the adjusting collimator 25 is respectively adjusted to the left, the right, the upper and the lower, the offset is 0.4mm for verification, and the indication of the optical power 23 is observed. If the optical power loss value after the offset is asymmetric, continuously adjusting jackscrews around the backup collimator 17 after the installed and adjusted collimator 25 is adjusted back to the original point of the position according to the result; when the difference of the optical power loss values after the displacement and the offset in the four directions is not more than 1dB, the maximum value point of the indication of the optical power meter 23 at the moment can be considered as the symmetrical center point of the collimator optical path, and the optical path of the backup collimator 17 is reflected by the 45-degree reflecting mirror 19 and then coincides with the optical path of the adjustment collimator 25, namely the optical path of the primary collimator 1, so that the error is better than +/-0.05 mm.

In this embodiment, the preparation before docking and adjustment includes the following steps:

1. placing an electronic level on the rotary joint rotor housing 30 and monitoring the readings;

2. controlling the rotary joint to rotate around the stator, recording the reading of the electronic level meter every 30 degrees;

3. Adjusting the base center of the stator shaft of the rotary joint according to the reading of the electronic level to enable the rotary shaft to be perpendicular to the ground, wherein the precision is better than +/-0.001 degrees;

in this embodiment, the method for adjusting the optical path direction of the transmitting end includes the following steps:

1. as shown in fig. 10, the emitting end of the spatial light transmission device is mounted on the rotary joint rotor shell 30, the positions of the 2 theodolites are adjusted so that the respective fields of view can be respectively aimed at two adjacent surfaces of the emission end standard prism 2, the auto-collimation lamps of the 2 theodolites are turned on, and the focal length of the 2 theodolites is adjusted to infinity to be respectively aimed at two adjacent surfaces of the emission end standard prism 2;

2. the third optical path adjusting gasket 13 of the transmitting end is repaired and ground, so that the pitching axis indication number of the corresponding surface of the sighting reference prism 2 of 2 theodolites is simultaneously within 90+/-0.001 degrees, the optical path of the transmitting end is ensured to be vertical to the ground, and the optical path of the transmitting end is ensured to be parallel to the rotating shaft of the rotary joint.

In this embodiment, the method for adjusting the direction of the light path of the receiving end includes the following steps:

1. the receiving end of the space light transmission unit is arranged on the stator shaft of the rotary joint, the positions of the 2 theodolites are adjusted to enable the respective fields of view of the 2 theodolites to aim at two adjacent surfaces of the receiving end standard prism 2 respectively, the auto-collimation lamps of the 2 theodolites are turned on, and the focal length of the 2 theodolites is adjusted to infinity to aim at two adjacent surfaces of the receiving end standard prism 2 respectively;

2. The pitching axis indication number of the corresponding surface of the 2 theodolites aiming reference prism 2 is simultaneously within 90+/-0.001 degrees through repairing and grinding the receiving end light path adjusting gasket, so that the receiving end light path is vertical to the ground, and the receiving end light path is further ensured to be parallel to the rotary joint rotary shaft.

In this embodiment, the method for adjusting radial displacement of the transmitting end and the receiving end includes the following steps:

1. the transmitting end primary collimator 1 is connected with the laser 22, the receiving end primary collimator 1 is connected with the optical power meter 23, and the transmitting end and the receiving end 45-degree reflecting mirror 19 are adjusted to a cut-out state, so that the transmitting end primary and the receiving end primary work;

2. rotating the rotary joint rotor shell 30 at a constant speed, adjusting radial jackscrews at the transmitting end and radial jackscrews at the receiving end to ensure that the indication number of the optical power meter 23 reaches the error requirement range in the rotating process of the rotary joint, finding out the position with the minimum space optical loss, and screwing up the mounting screw;

3. and sequentially measuring four working modes of aligning the transmitting end primary collimator 1 with the receiving end primary collimator 1, aligning the transmitting end primary collimator 1 with the receiving end backup collimator 17, aligning the transmitting end backup collimator 17 with the receiving end primary collimator 1 and aligning the transmitting end backup collimator 17 with the receiving end backup collimator 17, recording the optical power loss under each mode, and repeating the steps to readjust the radial displacement of the transmitting end and the receiving end until the optical power loss under the four working modes meets the design requirement, thereby ensuring the coincidence of the optical paths of the transmitting end and the receiving end and the rotation center shaft.

The device disclosed by the invention is not only suitable for a laser communication system, but also suitable for other fields needing optical switching.

The adjusting method is not only suitable for the space optical transmission unit, but also suitable for other fields requiring high-precision measurement of the collimator optical path.

The apparatus and method disclosed in the present application may be implemented in other manners. The above described device embodiments are only illustrative, e.g. the division of the units is only one logical function division, and there may be other divisions in practice, such as: multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or units, whether electrically, mechanically, or otherwise.

The units described as separate units may or may not be physically separate, and units displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units; some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated in one processing module, or each unit may be separately used as one unit, or two or more units may be integrated in one unit; the integrated units may be implemented in hardware or in hardware plus software functional units.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims

1. A spatial light transmission device for laser communication, comprising: a transmitting end and a receiving end;

the transmitting end and/or the receiving end respectively comprise: a primary collimator (1), a reference prism (2), a primary collimator fixing frame (6), a fixing frame (7), a backup collimator fixing frame (16) and a backup collimator (17);

The main collimator (1) and the main collimator fixing frame (6) are fixed on the fixing frame (7) through third screws (4); the backup collimator (17) and the backup collimator fixing frame (16) are fixed on the fixing frame (7) through first screws (15); the fixing frame (7) is fixed on the connecting piece (20) of the transmitting end and/or the receiving end through a second screw (11);

the main collimator (1) adjusts the light path direction and position of the collimator by adjusting a first light path adjusting gasket (5) and a first radial adjusting jackscrew (3); the backup collimator (17) adjusts the direction and the position of the collimator light path through adjusting a second light path adjusting gasket (18) and a second radial adjusting jackscrew (14); the fixing frame (7) adjusts the light path direction and position of the transmitting end or the receiving end through adjusting a third light path adjusting gasket (13) and a third radial adjusting jackscrew (12);

the switching between the main part and the backup light path is realized by the translation of a 45-degree reflecting mirror (19) through the cooperation of a ball screw (8), a guide rail sliding block (9) and a sliding block connecting piece (10).

2. The spatial light transmission device for laser communication as set forth in claim 1, wherein the spatial light transmission device is provided with a mechanism control unit which precisely judges the position of the 45 ° mirror (19) by detecting feedback of a grating scale and realizes high-precision closed-loop control of the position of the 45 ° mirror (19) by controlling a motor with a position repetition precision within ±0.1 mm.

3. A method of tuning a spatial light transmission device for laser communication, the spatial light transmission device for laser communication comprising: a transmitting end and a receiving end;

The switching between the main part and the backup light path is realized by the high-precision matching of the ball screw (8), the guide rail sliding block (9) and the sliding block connecting piece (10) and the translation of the 45-degree reflecting mirror (19);

the method for adjusting comprises the following steps:

step 1: the main collimator (1) and/or the backup collimator (17), the adjustment collimator (25), the laser (22), the circulator (21), the reference prism (2), the fourth plane mirror (24), the optical power meter (23), the theodolite and the six-dimensional adjusting frame to be tested are matched to split the adjustment reference;

step 2: transferring the pointing angle reference of the optical path of the primary collimator (1) and/or the backup collimator (17) to a fourth plane mirror (24);

step 3: and transferring the radial displacement reference of the optical path of the primary collimator (1) and/or the backup collimator (17) to an adjustment collimator (25) to realize adjustment of the optical path of the collimator.

4. A method of tuning a spatial light transmission device for laser communication according to claim 3, characterized in that the method of tuning the reference prism (2) comprises the steps of:

placing a fixing frame (7) on an air floatation table, wiping a mechanical reference surface (26) by dust-free cloth, installing a reference prism (2), screwing a screw, attaching a first plane mirror (27) to the mechanical reference surface (26), and adjusting the view field of the theodolite to enable the view field of the theodolite to be capable of simultaneously aiming at the reference prism (2) and the first plane mirror (27);

The auto-collimation lamp of the theodolite is turned on, the focal length of the theodolite is adjusted to infinity, the cross silk image reflected by the reference prism (2) and the first plane mirror (27) is observed, the base of the reference prism (2) is correspondingly ground according to the positions of the two cross silk images, the step is repeated to finally enable the cross silk image reflected by the reference prism (2) and the first plane mirror (27) to coincide, and then the error of the corresponding surface of the reference prism (2) and the first plane mirror (27) is better than +/-0.001 degrees.

5. A method of tuning a spatial light transmission device for laser communication according to claim 3, characterized in that said method of tuning a 45 ° mirror (19) comprises the steps of:

placing a fixing frame (7) on an air floatation table, wiping a mechanical reference surface (26) by dust-free cloth, placing a second plane mirror (28) on the mounting end surface of a backup collimator (17), and adjusting the view field of the theodolite to enable the theodolite to aim at a 45-degree reflecting mirror (19) and a third plane mirror (29) which is closely attached to the mechanical reference surface (26) at the same time;

the auto-collimation lamp of the theodolite is turned on, the focal length of the theodolite is adjusted to infinity, the cross silk images reflected by the 45-degree reflecting mirror (19), the second plane mirror (28) and the third plane mirror (29) are observed, and the two cross silk images are finally overlapped by repeating the steps according to the corresponding grinding mirror gaskets of the positions of the two cross silk images, so that the second plane mirror (28) is parallel to the normal line of the third plane mirror (29) after being reflected by the 45-degree reflecting mirror (19), and the error is better than +/-0.001 degrees.

6. A method of tuning a spatial light transmission device for laser communication according to claim 3, wherein the collimator pointing angle reference transfer method comprises the steps of:

placing a fixing frame (7) on an air floatation table, cutting out a 45-degree reflecting mirror (19) to enable a main collimator (1) to be in a working state, connecting the main collimator (1) with a circulator (21), a laser (22) and an optical power meter (23), opening the laser (22) and the optical power meter (23), placing a fourth plane mirror (24) fixed on a two-dimensional adjusting table at the front end, and adjusting an azimuth angle and a pitch angle by the fourth plane mirror (24) through the two-dimensional adjusting table;

the laser light path emitted by the primary collimator (1) is overlapped with the laser light path received after being reflected by the fourth plane mirror (24), at the moment, the optical power loss is minimum, and the indication of the optical power meter (23) reaches the maximum;

and starting from the position with the maximum indication of the optical power meter (23), respectively adjusting the azimuth angle and the pitch angle of the fourth plane mirror (24) vertically and horizontally to verify each deflection 3', and observing the indication of the optical power meter (23): if the optical power loss value after deflection is asymmetric, continuing to adjust the azimuth angle and the pitch angle of the fourth plane mirror (24) according to the result; when the difference of the optical power loss values after deflection in the four directions is not more than 1dB, the maximum value point of the indication of the optical power meter (23) is considered to be the symmetrical center point of the optical path of the primary collimator (1), so that the pointing angle reference of the primary collimator (1) is transferred to a fourth plane mirror (24) for measurement by a theodolite;

The field of view of the theodolite is adjusted to enable the theodolite to aim at the reference prism (2) and the fourth plane mirror (24) at the same time, an auto-collimation lamp of the theodolite is turned on, the focal length of the theodolite is adjusted to infinity, cross images reflected by the reference prism (2) and the fourth plane mirror (24) are observed, gaskets are adjusted according to the positions of the two cross images by correspondingly grinding the primary collimator (1), the two cross images are finally overlapped by repeating the steps, and when the optical path of the primary collimator (1) is perpendicular to the normal of the fourth plane mirror (24) and the normal of the reference prism (2), the error is better than +/-10'.

7. A method of tuning a spatial light transmission device for laser communication according to claim 3, wherein said collimator radial displacement reference transfer method comprises the steps of:

placing a fixing frame (7) on an air floatation table, cutting out a 45-degree reflecting mirror (19) to enable a main light path to be in a working state, placing an adjusting collimator (25) at a position which is a certain distance away from a main collimator (1) at the front part of a transmitting end and/or a receiving end, fixing the adjusting collimator (25) with a six-dimensional adjusting frame, placing a prism and a dial indicator on the six-dimensional adjusting frame, and measuring the pointing angle change and radial displacement change of the adjusting collimator (25) through the theodolite aiming prism and observing the readings of the dial indicator so as to avoid errors caused by the empty back of the six-dimensional adjusting frame;

The main collimator (1) is connected to a laser (22) or an optical power meter (23) through optical fibers, the mounting collimator (25) is connected to the optical power meter (23) or the laser (22) through optical fibers, the main collimator (1) is fixed through four-side jackscrews, the optical path direction and radial displacement of the mounting collimator (25) are adjusted through a six-dimensional adjusting frame to enable the indication of the optical power meter (23) to reach the maximum value, then the azimuth angle and the pitch angle of the mounting collimator (25) are respectively adjusted from left to right and from top to bottom, the deflection 3' of the pitch angle of the mounting collimator (25) is respectively adjusted from left to right, the radial displacement of the mounting collimator (25) is respectively adjusted from left to top to the bottom, the indication of the optical power meter (23) is observed for verification by 0.4 mm: if the corresponding optical power loss values after deflection and offset are asymmetric, continuously adjusting the light path direction and radial displacement of the adjusting collimator (25) according to the result; when the difference of corresponding optical power loss values after the four-direction angle deflection and the four-direction displacement deflection is not more than 1dB, the maximum value point of the indication of the optical power meter (23) at the moment is the symmetrical center point of the collimator light path, the light path of the alignment collimator (25) coincides with the light path of the main collimator (1), the radial displacement reference of the main collimator (1) is transferred to the alignment collimator (25), and the position is taken as the position origin of the alignment collimator (25);

The fixing frame (7) and the adjusting collimator (25) are kept motionless, the 45-degree reflecting mirror (19) is cut into to enable the backup light path to work, the backup collimator (17) is connected to the laser (22) or the optical power meter (23) through adjusting jackscrews around the backup collimator (17), the indication of the optical power meter (23) reaches the maximum value, and then from the position, the radial displacement of the adjusting collimator (25) is respectively adjusted up and down from left to right, and is respectively offset by 0.4mm for verification, and the indication of the optical power meter (23) is observed: if the optical power loss value after the offset is asymmetric, continuously adjusting jackscrews around the backup collimator (17) after the installed collimator (25) is adjusted back to the original point of the position according to the result; when the difference of the optical power loss values after the displacement and the offset in the four directions is not more than 1dB, the maximum value point of the indication of the optical power meter (23) is considered to be the symmetrical center point of the collimator optical path, and the optical path of the backup collimator (17) is reflected by the 45-degree reflecting mirror (19) and then coincides with the optical path of the adjustment collimator (25) and the optical path of the main collimator (1), so that the error is better than +/-0.05 mm.

8. The method for adjusting a spatial light transmission device for laser communication according to claim 3, wherein the method for adjusting the direction of the light path of the transmitting end comprises the steps of:

The method comprises the steps of installing a space light transmission unit transmitting end on a rotary joint rotor shell (30), adjusting the positions of 2 theodolites to enable the positions of the 2 theodolites to respectively aim at two adjacent surfaces of a transmitting end reference prism (2) in respective fields of view, turning on auto-collimation lamps of the 2 theodolites, and adjusting the focal length of the 2 theodolites to infinity to respectively aim at two adjacent surfaces of the transmitting end reference prism (2);

the third light path adjusting gasket (13) of the transmitting end is ground so that the back pitching axis indication number of the corresponding surface of the 2 theodolites aiming reference prism (2) is simultaneously within 90+/-0.001 degrees.

9. The method for adjusting a spatial light transmission device for laser communication according to claim 3, wherein the method for adjusting the direction of the light path of the receiving end comprises the steps of:

the receiving end of the space light transmission unit is arranged on the stator shaft of the rotary joint, the positions of the 2 theodolites are adjusted to enable the respective fields of view to respectively aim at two adjacent surfaces of the reference prism (2) of the receiving end, the auto-collimation lamps of the 2 theodolites are turned on, and the focal length of the 2 theodolites is adjusted to infinity to respectively aim at two adjacent surfaces of the reference prism (2) of the receiving end;

the back pitching axis indication number of the corresponding surface of the 2 theodolites aiming reference prism (2) is simultaneously within 90+/-0.001 degrees through repairing and grinding the receiving end light path adjusting gasket.

10. The method for adjusting a spatial light transmission device for laser communication according to any one of claims 3 to 9, wherein the method for adjusting radial displacement of the transmitting end and the receiving end comprises the steps of:

the transmitting end primary collimator (1) is connected with the laser (22), the receiving end primary collimator (1) is connected with the optical power meter (23), and the transmitting end and the receiving end 45-degree reflecting mirror (19) are adjusted to a cut-out state, so that the transmitting end primary and the receiving end primary work;

the rotor shell (30) of the rotary joint rotates at a constant speed, the indication of the optical power meter (23) reaches the error requirement range in the rotation process of the rotary joint by adjusting the radial jackscrew of the transmitting end and the radial jackscrew of the receiving end, the position with the minimum space optical loss is found, and the mounting screw is screwed;

and sequentially measuring four working modes of aligning the transmitting end primary collimator (1) with the receiving end primary collimator (1), aligning the transmitting end primary collimator (1) with the receiving end backup collimator (17), aligning the transmitting end backup collimator (17) with the receiving end primary collimator (1), aligning the transmitting end backup collimator (17) with the receiving end backup collimator (17), recording the optical power loss under each mode, and repeating the steps to readjust the radial displacement of the transmitting end and the receiving end until the optical power loss meets the design requirement and the coincidence of the transmitting end optical path and the receiving end optical path with the rotation center shaft if the optical power loss does not meet the requirement.