Light trap structure for absorbing and suppressing stray light in laser communication system

Abstract

The utility model relates to a light trap structure for absorbing and inhibiting stray light in a laser communication system. The light trap structure comprises a cavity, a parabolic reflector and an extinction body, a first light inlet is formed in one end of the cavity, and the directrix plane of the parabolic reflector is parallel to the section of the first light inlet; the extinction body comprises a second light inlet, a central extinction cone, an edge extinction cone and a hollow diaphragm, the second light inlet is communicated with the interior of the extinction body and the cavity, and the section of the second light inlet and the directrix plane of the parabolic mirror are inclined by a certain angle; the second light inlet can receive light rays reflected by the parabolic reflector; the extinction body internally comprises a central extinction cone and edge extinction cones, wherein the edge extinction cones are symmetrically arranged on the two sides of the central extinction cone. According to the utility model, light rays can be absorbed once or multiple times, and the proportion of stray light escape energy is reduced to the greatest extent.

Description

Technical Field

[0001] The utility model relates to a light trap structure, in particular to a light trap structure for absorbing and suppressing stray light in a laser communication system. Background Technique

[0002] In the field of laser communication, the transmitting optical path and the receiving optical path share an optical antenna. Part of the light in the light transmitting branch enters the light receiving branch directly or indirectly after being scattered by the mechanical structure. Since the photodetector and the capacitive coupling device are highly sensitive to the detection of light energy, the stray light generated by the transmitting branch received by them will affect the signal reception.

[0003] When the stray light reaches the surface of the mechanical structure, it will scatter randomly in all directions, while the stray light generated in the transmitting branch remains relatively parallel before entering the mechanical structure. The conventional solution is to use a light trap structure to process the stray light; the light trap can absorb and suppress the stray light in the laser communication system by coating the surface with a high-absorbance extinction paint.

[0004] In the existing light trap structures, most are one-time stray light absorption structures, and a small part of the energy will still scatter in all directions. Based on the above background, it is necessary to consider a light trap structure that can absorb light multiple times. Summary of the Invention

[0005] The purpose of the utility model is to overcome the above deficiencies and provide a light trap structure for absorbing and suppressing stray light in a laser communication system, which can absorb light once and multiple times and minimize the proportion of the energy of the stray light escaping.

[0006] According to the technical solution provided by the utility model, a light trap structure for absorbing and suppressing stray light in a laser communication system includes a cavity, a parabolic mirror and an extinction body arranged inside the cavity; one end of the cavity is provided with a first light inlet, and the directrix plane of the parabolic mirror is arranged parallel to the cross-section of the first light inlet;

[0007] The extinction body includes a second light inlet, a central extinction cone, an edge extinction cone and a hollow diaphragm. The second light inlet communicates the inside of the extinction body with the cavity. The cross-section of the second light inlet is inclined at a certain angle with respect to the directrix plane of the parabolic mirror, and the center of the cross-section of the second light inlet is located at the focus of the parabolic mirror. The second light inlet can receive the light reflected by the parabolic mirror; the inside of the extinction body includes a central extinction cone and an edge extinction cone, and the edge extinction cones are symmetrically arranged on both sides of the central extinction cone. The second light inlet is an inlet formed by symmetric hollow diaphragms.

[0008] As a further improvement of the present utility model, the inclination angle between the cross-section of the second light inlet and the directrix plane of the parabolic mirror is 40° to 55°.

[0009] As a further improvement of the present utility model, the overall shape of the light extinction body is a cylindrical structure, and the cone half vertex angle α of the central light extinction cone is 15° to 20°.

[0010] As a further improvement of the present utility model, the cone half vertex angle β of the edge light extinction cone of the light extinction body is 10° to 15°.

[0011] As a further improvement of the present utility model, the inside of the light extinction body is coated with light extinction paint.

[0012] As a further improvement of the present utility model, the diameter of the first light inlet is less than 20 mm.

[0013] As a further improvement of the present utility model, the volume of the cavity is less than 50 mm × 50 mm × 50 mm.

[0014] As a further improvement of the present utility model, the diameter of the second light inlet is less than 2.5 mm.

[0015] The beneficial effects of the present utility model are as follows:

[0016] The light extinction body structure of the present utility model is reasonable. The central light extinction cone and the edge light extinction cone can absorb light multiple times, and the hollow diaphragm can prevent part of the scattered light from escaping, forming a relatively good stray light absorption area; at the same time, through the cylindrical groove area, part of the light overflowing from the light extinction body and part of the scattered light in the cavity can also be absorbed, which can greatly reduce the proportion of the energy of the stray light escaping. Description of the Drawings

[0017] Figure 1 is the overall structure schematic diagram of the present utility model.

[0018] Figure 2 is the enlarged structure schematic diagram of the light extinction body of the present utility model.

[0019] Figure 3 is the installation position schematic diagram of the present utility model.

[0020] Figure 4 is the test data of the escaping light of the present utility model.

[0021] Description of the reference numerals: 1. First light inlet; 2. Cavity; 3. Parabolic mirror; 4. Second light inlet; 5. Light extinction body; 6. Central light extinction cone; 7. Edge light extinction cone; 8. Hollow diaphragm; 9. Cylindrical groove area. Detailed Embodiments

[0022] The present utility model will be further described below in conjunction with the embodiments in the accompanying drawings:

[0023] In a laser communication system, the transmitting branch and the receiving branch share an optical antenna. When the transmitting branch is operating, the light incident on the beam splitter will also be divided into two parts: transmitted light and reflected light. Among them, the reflected light is sent outside the opto-mechanical system, while the transmitted light will be incident on the mechanical structure to form stray light, which will directly or indirectly affect the receiving branch, such as Figure 3 As shown, the light trap is located at the position where the transmitted light is formed after the transmitting branch passes through the beam splitter, and absorbs the transmitted light to prevent the transmitted light from being incident on the mechanical structure.

[0024] A light trap structure for absorbing and suppressing stray light in a laser communication system, comprising a cavity 2 and a parabolic mirror 3 and an extinction body 5 provided inside the cavity 2; one end of the cavity 2 is provided with a first light inlet 1, and the directrix plane of the parabolic mirror 3 is arranged parallel to the cross-section of the first light inlet 1;

[0025] The extinction body 5 includes a second light inlet 4, a central extinction cone 6, an edge extinction cone 7, and a hollow diaphragm 8. The second light inlet 4 communicates with the inside of the extinction body 5 and the inside of the cavity 2. The cross-section of the second light inlet 4 is inclined at a certain angle to the directrix plane of the parabolic mirror 3, and the center of the cross-section of the second light inlet 4 is located at the focus of the parabolic mirror 3. The second light inlet 4 can receive the light reflected by the parabolic mirror 3; the inside of the extinction body 5 includes a central extinction cone 6 and an edge extinction cone 7, where the edge extinction cones 7 are symmetrically arranged on both sides of the central extinction cone 6, and the second light inlet 4 is an inlet formed by symmetric hollow diaphragms 8.

[0026] The inclination angle between the cross-section of the second light inlet 4 and the directrix plane of the parabolic mirror 3 is 40° - 55°; Figure 4 In order to establish the mechanical structure and set the surface properties through the tracepro software, the relative energy of the escaping light is measured at the receiver. Two sets of data are set. One set is that the light enters the extinction body 5 through the reflection of the edge of the standard parabolic mirror 3, and the other set is that the light enters the extinction body 5 through the reflection at the center of the parabolic mirror 3; from the data, it can be seen that the escaping energy respectively shows low valley values in the ranges of 40° - 45° and 50° - 55°. Therefore, it is more reasonable that the inclination angle between the cross-section of the second light inlet 4 of the present utility model and the directrix plane of the parabolic mirror 3 is 40° - 55°.

[0027] The overall shape of the light extinction body 5 is a cylindrical structure. The cone half vertex angle α of the central light extinction cone 6 is 15° to 20°; the cone half vertex angle β of the edge light extinction cone 7 in the light extinction body 5 is 10° to 15°; considering the comprehensive light extinction requirements and assembly volume, the angle α of the central light extinction cone is preferably 15° to 20°; the angle β of the edge light extinction cone is slightly lower than α.

[0028] The inside of the light extinction body 5 is coated with light extinction paint; multiple cylindrical groove areas 9 are arranged inside the cavity 2, and the cylindrical groove areas 9 are arranged around the light extinction body 5; the inside of the cylindrical groove areas 9 is coated with light extinction paint.

[0029] The diameter of the first light inlet 1 is less than 20 mm; the volume of the cavity 2 is less than 50 mm×50 mm×50 mm; the diameter of the second light inlet 4 is less than 2.5 mm.

[0030] In the conventional setting, the radius of the first light inlet 1 should be slightly larger than the radius of the stray light. The size of the second light inlet 4 is selected according to the divergence angle of the light beam. The smaller the radius of the second light inlet 4, the larger the stray light suppression ratio; the shapes of the first light inlet 1 and the second light inlet 4 are mainly circular.

[0031] The working mechanism of the present utility model is as follows:

[0032] The collimated stray light first enters the cavity 2 through the first light inlet 1, is incident on the parabolic mirror 3, and converges to the parabolic focus;

[0033] After passing through the focus, the light enters the inside of the light extinction body 5, and is first incident on the surface of the central light extinction cone 6 for one - time energy absorption. The secondary and multiple scattered lights will continuously consume energy in the central light extinction cone 6 and the edge light extinction cone 7; the hollow diaphragm 8 can also further absorb light;

[0034] Only a very small amount of energy of the light can pass through the second light inlet 4 and be incident on the surface of the parabolic mirror 3 again to escape from the light trap, and the escaped light can also be further absorbed by a part through the cylindrical groove area 9.

[0035] In this way, the present utility model can absorb the collimated stray light generated in the light emission branch of the laser communication system or the collimated stray light in other systems to the greatest extent.

Claims

1. An optical trap structure for absorbing and suppressing stray light in a laser communication system, characterized in that: The invention comprises a cavity (2), a parabolic reflector (3) and a light extinction body (5) arranged inside the cavity (2); a first light inlet (1) is arranged at one end of the cavity (2), and a directrix plane of the parabolic reflector (3) is arranged parallel to a cross section of the first light inlet (1); The extinction body (5) comprises a second light entrance (4), a central extinction cone (6), an edge extinction cone (7) and a hollow aperture (8); the second light entrance (4) connects the interior of the extinction body (5) with the interior of the cavity (2); the cross section of the second light entrance (4) is inclined at a certain angle to the directrix plane of the parabolic reflector (3), and the cross section center of the second light entrance (4) is located at the focus of the parabolic reflector (3); the second light entrance (4) can receive light reflected by the parabolic reflector (3); the interior of the extinction body (5) comprises a central extinction cone (6) and an edge extinction cone (7), wherein the edge extinction cones (7) are symmetrically arranged on both sides of the central extinction cone (6); and the second light entrance (4) is a light entrance formed by a symmetrical hollow aperture (8).

2. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The inclination angle between the cross section of the second light entrance (4) and the directrix plane of the parabolic reflector (3) is 40° to 55°.

3. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The overall shape of the extinction body (5) is a cylindrical structure, and the cone half apex angle α of the central extinction cone (6) is 15° to 20°.

4. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 3, characterized in that: The cone half apex angle β of the edge extinction cone (7) in the extinction body (5) is 10° to 15°.

5. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The interior of the matt body (5) is coated with matt paint.

6. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: A plurality of columnar groove areas (9) are arranged inside the cavity (2), and the columnar groove areas (9) are arranged around the matte body (5).

7. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 6, characterized in that: The inside of the cylindrical groove area (9) is coated with matte paint.

8. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The diameter of the first light entrance (1) is less than 20 mm.

9. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The volume of the cavity (2) is less than 50 mm*50 mm*50 mm.

10. The optical trap structure for absorbing and suppressing stray light in a laser communication system according to claim 1, characterized in that: The diameter of the second light entrance (4) is less than 2.5 mm.

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