Light path structure and satellite laser communication terminal

Abstract

The invention relates to a light path structure which is characterized in that a Z-block and a fast reflecting mirror are arranged on a universal frame, the fast reflecting mirror is located on one side of the Z-block and is coupled with a first channel of the Z-block, and a TX optical filter, a semi-transparent semi-reflecting sheet and a total reflecting sheet are fixed to the positions, at the first channel, the second channel and the third channel, of the side face of the other side of the Z-block respectively. The universal frame is provided with a light emitting end coupled with the TX optical filter, and the universal frame is provided with a light receiving end coupled with the semi-transparent and semi-reflective sheet; a four-quadrant detector is arranged at the position, corresponding to the fourth channel of the Z-block, of the universal frame, and a first converging lens fixed to the universal frame is coupled between the fourth channel of the Z-block and the four-quadrant detector. The satellite laser communication terminal comprises the optical path structure. The beneficial effects are that the Z-block is used to separate the emitted light from the received light, the light path is reversible, the number of light path parts can be reduced, the size is small, and the transmitting and receiving are stable and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite communication, in particular to an optical path structure and a satellite laser communication terminal. BACKGROUND

[0002] Inter-satellite communication technology can be divided into microwave communication, terahertz communication and laser communication. Laser communication has the advantages of large bandwidth (high frequency of laser communication, the bandwidth for communication is much larger than radio frequency), small volume, mass and power consumption (the wavelength of laser communication is small, so that the diameter of the transmitter and the beam divergence of the system are smaller, so that the SWaP of laser communication is lower than that of a radio frequency system with similar performance), strong anti-interference ability (narrow beam width, making it difficult to be intercepted and interfered) and the like. The disadvantages include the requirements for beam pointing, the influence of weather on signals, etc.

[0003] Common satellite laser communication terminals, such as the OSIRIS4CubeSat laser terminal named by Germany DLR / Tesat, can realize laser communication on a cubic satellite, with a size of about 0.3U (95mmx95mmx30mm), a mass of <400g, a maximum power consumption of 8.5W, and a rate of 100M. The SOTA structure of the Japanese laser communication terminal, with a mass of 5.9kg and a power consumption of 40W, has a rate of 10M. The above two satellite laser communication terminals have a relatively large size and cannot meet the miniaturization requirement. For a miniaturized satellite laser communication terminal, it is a key factor in the optical path design to reduce the number of components and the size, and to ensure that the angle can be adjusted in real time to achieve the best optical path effect and ensure stable and reliable transmission and reception. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an optical path structure and a satellite laser communication terminal to overcome the deficiencies in the prior art.

[0005] The technical solution of the present application to solve the above technical problem is as follows: An optical path structure comprises a gimbal, a Z-block and a fast mirror arranged on the gimbal, the fast mirror is arranged on one side of the Z-block and coupled with a first channel of the Z-block, the Z-block is fixed with a TX filter, a half-mirror and a full mirror at a first channel, a second channel and a third channel on the side surface of the other side respectively, the TX filter only allows transmitting light to pass through, the gimbal is provided with a light emitting end coupled with the TX filter, the gimbal is provided with a light receiving end coupled with the half-mirror, the half-mirror allows part of the received light to pass through and reflects the remaining received light, the wavelength of the transmitting light is different from that of the received light; a four-quadrant detector is arranged on the gimbal corresponding to a fourth channel of the Z-block, and a first converging lens fixed with the gimbal is coupled between the fourth channel of the Z-block and the four-quadrant detector.

[0006] The beneficial effects of the present application are that the wavelength of the transmitting light (TX) is different from that of the received light (RX), the TX light and the RX light are separated by the Z-block, and the optical path is reversible, thereby reducing the number of optical path components, small in size (standard rectangular, less wasted space), the length and width dimensions can be 26mm*13mm, the angle can be adjusted in real time through the fast mirror to achieve the best effect of the optical path, and the transmission and reception are stable and reliable.

[0007] On the basis of the above technical scheme, the present application can also be improved as follows.

[0008] Further, the gimbal is provided with an expansion lens coupled with the fast mirror.

[0009] The above further beneficial effects are that the expansion lens can converge and then diverge the small size collimated light spot, for the received light, the expansion lens can converge the divergent light.

[0010] Further, the gimbal is provided with a bidirectional collimating lens coupled with the expansion lens, and the expansion lens is arranged between the bidirectional collimating lens and the fast mirror.

[0011] Further, the bidirectional collimating lens is a large-aperture bidirectional collimating lens.

[0012] Further, the aperture of the bidirectional collimating lens is greater than 5mm.

[0013] The above further beneficial effects are that for the transmitting light path, a large-aperture bidirectional collimating lens is added behind the divergent light, which can expand the small spot of the laser in the light emitting end into a large spot, increasing the communication margin, and for the received light path, the large spot can be reduced to a small spot.

[0014] Further, the light emitting end comprises a laser, a first collimating lens and an optical isolator, and the emitting light of the laser is coupled into the first channel of the Z-block in sequence through the first collimating lens, the optical isolator and the TX filter.

[0015] Further, the light receiving end comprises an RX filter, a second converging lens and a receiving detector, and the receiving light which is transmitted by the semi-transparent and semi-reflective sheet is coupled into the receiving detector in sequence through the RX filter and the second converging lens, and the RX filter only allows the receiving light to be transmitted.

[0016] Further, the light splitting ratio of the semi-transparent and semi-reflective sheet is 50:50.

[0017] Further, the wavelength of the emitting light is 1540nm, and the wavelength of the receiving light is 1560nm.

[0018] Based on the above technical scheme, the application further provides a satellite laser communication terminal comprising the optical path structure.

[0019] The above further beneficial effects are that the number of parts is small, the size is small, and the transmission and reception are stable and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Fig. 1 is a structural diagram of an optical path structure in the application; Figure 2 Fig. 2 is a structural diagram of a position where receiving light enters the optical path structure and is finally incident on a four-quadrant detector which is not at the center of the four-quadrant detector; Figure 3 Fig. 3 is a structural diagram of a four-quadrant detector.

[0021] In the drawings, the components represented by the respective reference numerals are listed as follows: 1, gimbal, 2, Z-block, 3, fast mirror, 4, TX filter, 5, semi-transparent and semi-reflective sheet, 6, fully reflective sheet, 7, four-quadrant detector, 8, first converging lens, 9, beam expander lens, 10, bidirectional collimating lens, 11, laser, 12, first collimating lens, 13, optical isolator, 14, RX filter, 15, second converging lens, 16, receiving detector. DETAILED DESCRIPTION

[0022] The principles and characteristics of the application are described below in combination with the drawings, and the examples are only used to explain the application and are not used to limit the scope of the application.

[0023] Example 1 As shown in Figure 1 , Figure 2 , Figure 3 An optical path structure comprises: The gimbal 1, the Z-block 2 and the fast mirror 3, wherein the Z-block 2 and the fast mirror 3 are respectively arranged on the gimbal 1, the fast mirror 3 is distributed on the gimbal 1 in an inclined manner, the fast mirror 3 is located on one side of the Z-block 2 and is coupled with a first channel of the Z-block 2, and the Z-block 2 is fixed with a TX filter 4, a half-transmission half-reflection film 5 and a full-reflection film 6 at a first channel, a second channel and a third channel respectively on the side surface on the other side, wherein the TX filter 4 only allows the transmission light to pass through and filters out other wavelength interference light, and the gimbal 1 is provided with a light emitting end coupled with the TX filter 4; The gimbal 1 is provided with a light receiving end coupled with the half-transmission half-reflection film 5, the half-transmission half-reflection film 5 allows part of the received light to pass through and reflects the remaining received light, and the wavelengths of the transmission light and the received light are different, so that the received light can be prevented from entering the light emitting end through the TX filter 4; the gimbal 1 is provided with a four-quadrant detector 7 at a fourth channel corresponding to the Z-block 2, the four-quadrant detector 7 is composed of a plurality of independent small PDs arranged in an array form, and a first converging lens 8 fixed with the gimbal 1 is coupled between the fourth channel of the Z-block 2 and the four-quadrant detector 7; When receiving light, the received light emitted by the remote satellite terminal in communication therewith is reflected by the fast mirror 3, coupled into the first channel of the Z-block 2, then incident on the TX filter 4, totally reflected by the TX filter 4 into the second channel, then incident on the half-transmission half-reflection film 5, allowed by the half-transmission half-reflection film 5 to pass through part of the received light and reflect the remaining received light, and then coupled into the light receiving end, and the remaining received light reflected by the half-transmission half-reflection film 5 is incident on the full-reflection film 6, then totally reflected by the full-reflection film 6 into the fourth channel, then emitted from the Z-block 2 through the fourth channel and incident on the first converging lens 8, then incident on the four-quadrant detector 7 after being converged by the first converging lens 8, if the received light emitted by the remote satellite terminal at a distance exists slight skew or the satellite has slight vibration during high-speed movement, etc., resulting in improper light path, then the position where the received light is finally incident on the four-quadrant detector 7 after entering the light path structure will not be at the center of the four-quadrant detector 7, but will be misaligned, which means that the received light coupled into the light receiving end also exists misalignment, so the angle of the light path structure can be adjusted by adjusting the angle of the fast mirror 3 to adapt to the angle of the received light emitted by the remote satellite terminal at a distance, i.e. 100% alignment, so as to ensure that the position where the received light is incident on the four-quadrant detector 7 is at the center of the four-quadrant detector 7, and the received light coupled into the light receiving end does not exist misalignment; The light path structure, when emitting light, the emitted light emitted by the light emitting end enters the first channel of the Z-block 2 after the TX filter 4, and then is coupled to the fast mirror 3, and the fast mirror 3 reflects the emitted light out of the light path structure and is coupled into the remote satellite terminal in communication with it.

[0024] In the application, the wavelength of the emitted light (TX) is different from the wavelength of the received light (RX), the TX light and the RX light are separated by the Z-block 2, and the light path is reversible, so that the number of light path components can be reduced, the size is small (standard rectangle, less wasted space), the length and width size can be 26mm*13mm, the angle can be adjusted in real time through the fast mirror to achieve the best effect of the light path, and the transmission and reception are stable and reliable.

[0025] Embodiment 2 As shown in the figure, this embodiment is a further improvement on the basis of embodiment 1, and the specific improvements are as follows: Figure 1 A beam expander lens 9 coupled with the fast mirror 3 is arranged on the gimbal 1, for the emitted light, the beam expander lens 9 can converge and then diverge the small size collimated light spot, and for the received light, the beam expander lens 9 can converge the divergent light. A bidirectional collimating lens 10 coupled with the beam expander lens 9 is arranged on the gimbal 1, and the beam expander lens 9 is between the bidirectional collimating lens 10 and the fast mirror 3, and the bidirectional collimating lens 10 preferably adopts a large-aperture bidirectional collimating lens, for the emitted light path, a large-aperture bidirectional collimating lens is added behind the divergent light, which can expand the small spot of the laser 11 in the light emitting end to a large spot, and increase the communication margin, and for the received light path, the large spot can be reduced to a small spot, and the aperture of the bidirectional collimating lens 10 is above 5mm.

[0026] Embodiment 3

[0027] As shown in the figure, this embodiment is a further improvement on the basis of embodiment 1 or 2, and the specific improvements are as follows: The light emitting end includes a laser 11, a first collimating lens 12 and an optical isolator 13, the laser 11, the first collimating lens 12 and the optical isolator 13 are arranged on the gimbal 1, and the emitted light of the laser 11 is coupled into the first channel of the Z-block 2 in sequence after the first collimating lens 12, the optical isolator 13 and the TX filter 4. Figure 1 Embodiment 4 As shown in the figure, this embodiment is a further improvement on the basis of embodiment 1 or 2 or 3, and the specific improvements are as follows:

[0028] Figure 1 ​​​The optical receiver includes an RX filter 14, a second converging lens 15, and a receiver detector 16. The RX filter 14, the second converging lens 15, and the receiver detector 16 are respectively mounted on the universal joint 1. The received light transmitted by the semi-transparent and semi-reflective film 5 passes through the RX filter 14 and the second converging lens 15 in sequence and is then coupled into the receiver detector 16. The RX filter 14 only allows the received light to pass through.

[0029] Example 5 like Figure 1 As shown, this embodiment is a further improvement on embodiment 1, 2, 3, or 4, as detailed below: The preferred spectral ratio of the semi-transparent and semi-reflective film 5 is 50:50. Of course, other spectral ratios may be used in practical applications.

[0030] Example 6 like Figure 1 As shown, this embodiment is a further improvement on any one of embodiments 1 to 5, as detailed below: The wavelength of the emitted light is 1540nm, the wavelength of the received light is 1560nm, the TX light wavelength of the remote satellite terminal communicating with it is 1560nm, and the RX light wavelength is 1540nm. In practical applications, the use of other wavelengths of light is not excluded, but it is generally around 1550nm.

[0031] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An optical path structure, characterized in that, The application relates to a light path structure, which comprises a gimbal (1), a Z-block (2) arranged on the gimbal (1) and a fast reflection mirror (3) arranged on one side of the Z-block (2) and coupled with a first channel of the Z-block (2), wherein TX filters (4) are fixed on the Z-block (2) at a first channel, a second channel and a third channel on the side of the other side of the Z-block (2), the TX filters (4) only allow transmitting light to pass through, a light emitting end of the gimbal (1) is coupled with the TX filters (4), a light receiving end of the gimbal (1) is coupled with a half-mirror (5), the half-mirror (5) allows part of receiving light to pass through and reflects the remaining receiving light, and the wavelength of the transmitting light is different from that of the receiving light; a four-quadrant detector (7) is arranged on the gimbal (1) at a fourth channel of the Z-block (2), and a first converging lens (8) fixed on the gimbal (1) is coupled between the fourth channel of the Z-block (2) and the four-quadrant detector (7). The gimbal (1) is provided with a beam expanding lens (9) coupled with the fast reflection mirror (3).

2. The optical path structure according to claim 1, wherein The gimbal (1) is provided with a bidirectional collimating lens (10) coupled with the beam expanding lens (9), and the beam expanding lens (9) is arranged between the bidirectional collimating lens (10) and the fast reflection mirror (3).

3. The optical path structure according to claim 2, wherein The bidirectional collimating lens (10) is a large-aperture bidirectional collimating lens.

4. The optical path structure according to claim 3, wherein The aperture of the bidirectional collimating lens (10) is larger than 5 mm.

5. An optical path structure according to claim 3 or 4, characterized in that The light emitting end comprises a laser (11), a first collimating lens (12) and an optical isolator (13), transmitting light of the laser (11) is sequentially coupled into the first channel of the Z-block (2) through the first collimating lens (12), the optical isolator (13) and the TX filters (4).

6. The optical path structure according to claim 1, wherein The light receiving end comprises RX filters (14), a second converging lens (15) and a receiving detector (16), receiving light of the half-mirror (5) is sequentially coupled into the receiving detector (16) through the RX filters (14) and the second converging lens (15), and the RX filters (14) only allow receiving light to pass through.

7. The optical path structure according to claim 1, wherein The light splitting ratio of the half-mirror (5) is 50:

50.

8. The optical path structure according to claim 1, wherein The wavelength of the transmitting light is 1540 nm, and the wavelength of the receiving light is 1560 nm.

9. The optical path structure according to claim 1, wherein The application further relates to a light path structure as claimed in any one of claims 1-9.

10. A satellite laser communication terminal, characterized by ​ ​

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