An optical antenna and communication terminal

Abstract

This application discloses an optical antenna and a communication terminal. The optical antenna includes a first light source assembly and an optical element. The first light source assembly is used to emit a first light beam toward the optical element. The optical element includes a reflective region for reflecting the first light beam, and the reflective region covers the central region of the first light spot formed by the first light beam on the optical element. The optical element also includes a transmission region for transmitting a second light beam, which is an external light beam. Alternatively, the optical antenna also includes a second light source assembly, and the second light beam is a light beam emitted by the second light source assembly toward the optical element. The energy distribution of the second light beam is different from that of the first light beam. The transmission region covers the central region of the second light spot formed by the second light beam on the optical element. The optical element is used to combine the first light beam and the second light beam through the reflective region and the transmission region. In this way, the two light beams are combined by means of energy distribution without relying on the wavelength or polarization characteristics of the light source itself.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to an optical antenna and a communication terminal. Background Technology

[0002] In optical communication, broadband beam splitters (a common non-polarized beam splitter that splits light according to energy ratio) or polarized beam splitters are typically used for beam combining. Broadband beam splitters mainly combine beams by utilizing the wavelength characteristics of the light source itself, while polarized beam splitters mainly combine beams by utilizing the polarization characteristics of the light source itself. Summary of the Invention

[0003] This application provides an optical antenna and a communication terminal, which are used to provide an optical antenna that can combine beams without relying on the wavelength or polarization characteristics of the light source itself.

[0004] In a first aspect, embodiments of this application provide an optical antenna, including a first light source assembly and optical elements, wherein:

[0005] The first light source assembly is used to emit a first light beam toward the optical element;

[0006] The optical element includes a reflective region for reflecting the first light beam, and the reflective region covers the central region of the first light spot formed by the first light beam on the optical element.

[0007] The optical element further includes a transmission region for transmitting a second light beam, which is an external light beam received by the optical antenna; alternatively, the optical antenna further includes a second light source assembly that emits the second light beam toward the optical element; the energy distribution of the second light beam and the first light beam are different; the transmission region covers the central region of the second light spot formed by the second light beam on the optical element;

[0008] The optical element is used to combine the first beam and the second beam through the reflection region and the transmission region.

[0009] In some embodiments, the reflective region is also used to reflect external light beams received by the optical antenna;

[0010] The optical element is also used to split the external light beam received by the optical antenna through the reflection region and the transmission region.

[0011] In some embodiments, the surface of the reflective region facing the first light source assembly is coated with a reflective film;

[0012] When the second beam is an external beam received by the optical antenna, the surface of the transmission region facing the second light source component is coated with a transmission film; when the second beam is a beam emitted by the second light source component, the opposite two surfaces of the transmission region are coated with transmission films.

[0013] In some embodiments, the reflecting region is a reflector and the transmitting region is an intensifying lens.

[0014] In some embodiments, the surface of the reflective region facing the first light source assembly is coated with a reflective film, or the reflective region is a reflective mirror;

[0015] The transmission area is hollowed out.

[0016] In some embodiments, the surface of the reflective region facing the first light source assembly is coated with a reflective film, and the transmission region is an intensifying lens, or;

[0017] The reflecting area is a reflector. When the second beam is an external beam received by the optical antenna, the surface of the transmission area facing the second light source component is coated with a transmission film. When the second beam is a beam emitted by the second light source component, the opposite two surfaces of the transmission area are coated with transmission films.

[0018] In some embodiments, the first light spot and the second light spot partially overlap, or the first light spot is located inside the second light spot, or the second light spot is located inside the first light spot.

[0019] In some embodiments, the difference between the wavelengths of the first beam and the second beam is less than a preset value.

[0020] In some embodiments, the difference in polarization characteristics between the first beam and the second beam is less than a preset requirement.

[0021] Secondly, embodiments of this application provide a communication terminal, including any of the optical antennas described above.

[0022] In this embodiment, the optical antenna includes a first light source assembly and an optical element. The first light source assembly is used to emit a first light beam toward the optical element. The optical element includes a reflective region for reflecting the first light beam, and the reflective region covers the central region of the first light spot formed by the first light beam on the optical element. The optical element also includes a transmission region for transmitting a second light beam, which is an external light beam received by the optical antenna. Alternatively, the optical antenna also includes a second light source assembly, the second light beam being a light beam emitted by the second light source assembly toward the optical element, and the transmission region covering the central region of the second light spot formed by the second light beam on the optical element. The optical element is used to combine the first light beam and the second light beam through the reflective region and the transmission region. Because the energy distributions of the first beam and the second beam are different, when both the first beam and the second beam are projected onto the optical element, the central regions of the first spot formed by the first beam and the second spot formed by the second beam will not completely overlap. To address this, a reflective region containing the central region of the first spot (i.e., the energy concentration region of the first beam) and a transmission region containing the central region of the second spot (i.e., the energy concentration region of the second beam) can be provided on the optical element. The first beam is reflected by the reflective region and the second beam is transmitted by the transmission region, thereby combining the first beam and the second beam by means of the energy distribution, without relying on the wavelength or polarization characteristics of the light source itself. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0024] Figure 1 This is a schematic diagram of an optical antenna in related technologies;

[0025] Figure 2 This is a schematic diagram of an optical antenna in related technologies;

[0026] Figure 3 A schematic diagram of an optical antenna provided for an embodiment of this application;

[0027] Figure 4 A schematic diagram of a first light spot and a second light spot provided for an embodiment of this application;

[0028] Figure 5 A schematic diagram of yet another optical antenna provided in an embodiment of this application;

[0029] Figure 6 A schematic diagram of yet another first and second light spots provided in the embodiments of this application;

[0030] Figure 7 This is a schematic diagram of the structure of a communication terminal provided in an embodiment of this application. Detailed Implementation

[0031] In order to provide an optical antenna that can combine beams without relying on the wavelength or polarization characteristics of the light source itself, embodiments of this application provide an optical antenna and a communication terminal.

[0032] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application. Furthermore, the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0033] In space laser communication, beam combining is typically achieved using either a broadband beam splitter (a commonly used non-polarized beam splitter that splits light according to energy ratio) or a polarized beam splitter. Broadband beam splitters primarily utilize the wavelength characteristics of the light source itself for beam combining, while polarized beam splitters primarily utilize the polarization characteristics of the light source itself. These two beam combining methods will be described in detail below.

[0034] See Figure 1 , Figure 1 This is a schematic diagram of the operation of an optical antenna 100 in related technology, including a first light-emitting component 01, a second light-emitting component 02, and a broadband beam splitter 03. The first light-emitting component 01 emits a light beam 11, the second light-emitting component 02 emits a light beam 22, and the broadband beam splitter 03 combines the light beams 11 and 22 into a light beam 33. Subsequently, the light beam 33 enters the light-receiving component 04 of another optical antenna. However, the broadband beam splitter 03 combines the beams according to energy ratio. Considering both transmission and reception, a 50% transmission and 50% reflection ratio is optimal. Thus, only 50% of the energy of the light beam 11 is transmitted, and only 50% of the energy of the light beam 22 is reflected, resulting in a 50% energy loss. During beam splitting, the optical path is reversed, and the beam to be split also has 50% of its energy transmitted and 50% reflected, again resulting in a 50% energy loss.

[0035] See Figure 2 , Figure 2This is a schematic diagram of another optical antenna 200 in the related technology, including a first light-emitting component 01, a second light-emitting component 02, a first polarization controller 05, a second polarization controller 06, and a polarization beam splitter 07. The first light-emitting component 01 emits a light beam 11, the second light-emitting component 02 emits a light beam 22, the first polarization controller 05 polarizes the light beam 11, the second polarization controller 06 polarizes the light beam 22, and the polarization beam splitter 07 combines the polarized light beams 11 and 22 into a single light beam 33. Subsequently, the light beam 33 enters the light-receiving component 04 of another antenna. However, the problem with the polarization beam splitter 07 is that it requires polarizing the light beams before polarization beam combining, which limits its application scenarios and increases the size and complexity of the optical path. When splitting the beam, the optical path is reversed, and the same problems exist.

[0036] To address the aforementioned issues, in this embodiment, the energy distribution of the beams on the two optical paths is differentiated through optical design. The central regions of the light spots formed by the two beams projected onto the optical element do not completely overlap. That is, the two beams have different energy concentration regions on the optical element. By utilizing these different energy concentration regions, the optical element allows most of the energy of the beam on one optical path to pass through and most of the energy of the beam on the other optical path to be reflected. Ultimately, the beams on the two optical paths can achieve spatial beam combining or splitting with high efficiency without relying on polarization or wavelength characteristics.

[0037] See Figure 3 , Figure 3 A schematic diagram of the operation of an optical antenna 300 provided in this application embodiment includes a first light source assembly 10, an optical element 20, and a beam-expanding transceiver antenna 30, wherein:

[0038] The first light source assembly 10 is used to emit a first beam toward the optical element 20;

[0039] The optical element 20 includes a reflective region for reflecting the first beam. The reflective region covers the central region of the first light spot formed by the first beam on the optical element 20. The central region of the first light spot refers to the region within a preset distance range from the center of the first light spot. Generally, the energy of the beam is concentrated in the central region of the light spot, so the central region of the first light spot is the energy concentration region of the first beam.

[0040] The optical element 20 also includes a transmission region for transmitting a second beam, which is an external beam received by the optical antenna. Generally, when external light shines on the beam-expanding transceiver antenna 30 (e.g., a 10x beam-expanding transceiver antenna), it is focused into a parallel beam (i.e., the external beam) and projected onto the optical element 20. The energy distribution of the second beam is different from that of the first beam. The transmission region covers the central region of the second light spot formed by the second beam on the optical element 20. The central region of the second light spot refers to the area within a preset distance from the center of the second light spot. Since the energy of the beam is concentrated in the central region of the spot, the central region of the second light spot is the energy concentration area of ​​the second beam.

[0041] Optical element 20 is used to reflect the first beam through the reflection region and transmit the second beam through the transmission region, thereby combining the first and second beams, that is, aligning the optical axes of the first and second beams. Afterwards, the first beam, after being reflected, is emitted outwards through the beam-expanding transceiver antenna 30, and the second beam, after being transmitted, enters subsequent optoelectronic processing devices.

[0042] In practical applications, after the external light beam received by the optical antenna is projected onto the optical element 20, it will be transmitted by the transmission area and reflected by the reflection area. Accordingly, the optical element 20 is also used to split the external light beam through the reflection area and the transmission area.

[0043] In some embodiments, the first light source assembly 10 may include a light-emitting device and a collimating lens. The light-emitting device may be a light-emitting diode, whose fast-axis divergence angle and slow-axis divergence angle may have a significant difference. A first beam with a nearly rectangular spot shape can be formed by a single aspherical collimating lens. See also Figure 4 , Figure 4 This is a schematic diagram of a first light spot and a second light spot provided in an embodiment of this application. The bright area inside is the first light spot, the elliptical area is the second light spot, and the circular hole in the middle is the background area.

[0044] In some embodiments, the reflective area can be Figure 4 The rectangular region shown can be considered as the elliptical region minus the rectangular region. Furthermore, to flexibly adjust reflection efficiency, the reflection region can be larger or smaller than the rectangular region, and similarly, the transmission region can be correspondingly reduced or expanded to flexibly adjust transmission efficiency.

[0045] Based on the comparison of experimental data, in Figure 3 Using optical element 20 compared to using broadband beam splitter 03 can improve the overall link gain of the transceiver link by approximately 4.93 dB.

[0046] See Figure 5 , Figure 5A schematic diagram of another optical antenna 400 provided in this application embodiment includes a first light source assembly 10, an optical element 20, a beam-expanding transceiver antenna 30, and a second light source assembly 40, wherein:

[0047] The first light source assembly 10 is used to emit a first light beam toward the optical element 20, and the second light source assembly 40 is used to emit a second light beam toward the optical element 20. The energy distribution of the second light beam and the first light beam are different.

[0048] The optical element 20 includes a reflective region for reflecting the first light beam. The reflective region covers the central region of the first light spot formed by the first light beam on the optical element 20, that is, the reflective region covers the energy concentration region of the first light beam.

[0049] The optical element 20 also includes a transmission region for transmitting the second beam. The transmission region covers the central region of the second spot formed by the second beam on the optical element 20, that is, the transmission region covers the energy concentration region of the second beam.

[0050] Optical element 20 is used to combine the first beam and the second beam through the reflection region and the transmission region. Subsequently, the combined beam can be transmitted outward through beam-expanding transceiver antenna 30, such as a 10x beam-expanding transceiver antenna.

[0051] In practical applications, when the external light beam received by the optical antenna through the beam-expanding transceiver antenna 30 is projected onto the optical element 20, the external light beam will be transmitted through the transmission region and reflected by the reflection region. Accordingly, the optical element 20 is also used to split the external light beam received by the optical antenna through the reflection region and the transmission region.

[0052] In some embodiments, both the first light source assembly 10 and the second light source assembly 40 may include a light-emitting device, such as a Gaussian light source, and a collimating lens. Furthermore, the wavelengths of the Gaussian light sources are the same, while the focal lengths of the collimating lenses are different. For example, the first light source assembly 10 emits a collimated beam with a wavelength of 1550 nm and a diameter of 1 mm, and the second light source assembly 40 emits a collimated beam with a wavelength of 1550 nm and a diameter of 6 mm. In this case, both the first and second beams form circular light spots. See also... Figure 6 , Figure 6 This is a schematic diagram of another first light spot and a second light spot provided in an embodiment of this application. The small gray circle represents the first light spot formed by the first beam, the large bright circle represents the second light spot formed by the second beam, and the small black circle in the middle represents the background area.

[0053] To maximize the reflection of the first beam and the transmission of the second beam, the reflection area can be the region where the first beam spot is located, i.e., the small gray circle region. The transmission area can be the non-overlapping area between the second and first beam spots, i.e., the area of ​​the large bright circle minus the small gray circle. Alternatively, to allow for flexible adjustment of reflection efficiency, the reflection area can also be a portion of the first beam spot; for example, the reflection area could be the central region of the small gray circle. Similarly, to allow for flexible adjustment of transmission efficiency, the transmission area can be a portion of the non-overlapping area between the second and first beam spots, or it can be the non-overlapping area of ​​the second and first beam spots plus a portion of the outer periphery of the small gray circle.

[0054] Based on the comparison of simulation data, in Figure 5 Using optical element 20 can improve emission efficiency by 5.433 dB compared to using broadband beam splitter 03.

[0055] exist Figure 4 and Figure 6 In this case, the first light spot is located inside the second light spot. In fact, the second light spot can also be located inside the first light spot, or the first light spot and the second light spot can only partially overlap each other.

[0056] In addition, in practical applications, Figure 3 and Figure 5 The optical element 20 can take many forms. The following are examples of the forms of the optical element 20.

[0057] The first type involves coating both the reflective and transmissive areas.

[0058] For the reflective area, a reflective film is coated on the side surface of the reflective area facing the first light source assembly 10, while the other side surface of the reflective area facing away from the first light source assembly 10 may or may not be coated with a reflective film.

[0059] For the transmission region, when the second beam is an external beam (i.e.) Figure 3 In the case where the transmission region faces the second light source assembly 40, a transmission film is coated on the side surface; when the second beam is a beam emitted by the second light source assembly 40 (i.e., Figure 5 In the case of transmission, both sides of the transmission area are coated with a transmission film.

[0060] The second type involves placing mirrors in both the reflection and transmission areas.

[0061] Specifically, the reflecting area is a reflector, and the transmitting area is an intensifying lens. Taking the first light spot being contained within the second light spot as an example, an intensifying lens can be selected, and then a hole is punched in the intensifying lens at the position corresponding to the reflecting area, and the reflector is inserted. Taking the second light spot being contained within the first light spot as an example, a reflector can be selected, and then a hole is punched in the reflector at the position corresponding to the transmitting area, and the intensifying lens is inserted.

[0062] The third type involves hollowing out the transmission area and coating or installing a reflector in the reflection area.

[0063] Considering that air also has a transmission effect, in some embodiments, the transmission area can be perforated. Furthermore, when the reflective area is coated, the surface of the reflective area facing the first light source assembly 10 is coated with a reflective film.

[0064] The fourth type involves setting one mirror in the reflection area and the other in the transmission area, with a coating on the other.

[0065] Case 1: Coating the reflective area and setting a mirror in the transmissive area.

[0066] The surface of the reflective area facing the first light source assembly 10 is coated with a reflective film, and the transmission area is an intensifying lens.

[0067] Scenario 2: A mirror is placed in the reflective area, and a coating is applied to the transmissive area.

[0068] The reflecting area is a reflector. For the transmitting area, when the second beam is an external beam, the surface of the transmitting area facing the second light source component 40 is coated with a transmission film; when the second beam is a beam emitted by the second light source component 40, the surfaces on both sides of the transmitting area can be coated with transmission films.

[0069] In this context, an anti-reflective coating refers to a thin film that increases light transmittance, a reflective coating refers to a thin film that reflects light, an anti-reflective lens refers to an optical mirror that increases light transmittance, and a reflective mirror refers to an optical mirror that reflects light. Considering that a dichroic mirror can also reflect light, a dichroic mirror can be used instead of a reflective mirror. Furthermore, the transmittance of the anti-reflective coating or anti-reflective lens can be selected by technicians according to actual needs, and the reflectance of the reflective coating or reflective mirror can also be selected by technicians according to actual needs; these details will not be elaborated further here.

[0070] In practical applications, Figure 1 The broadband beam splitter 03 can effectively process two beams with different wavelengths, such as splitting or combining them, but it has difficulty processing two beams with similar wavelengths (i.e., the difference between their wavelengths is less than a preset value). However, the optical antenna in this embodiment processes beams based on their energy distribution. Therefore, even if the wavelengths of the first and second beams are similar, as long as their energy distributions are different, the first and second beams can be split or combined relatively well.

[0071] in addition, Figure 2The polarization beam splitter 07 in the original text can effectively process two beams with different wavelength polarization characteristics (i.e., the difference between their polarization characteristics is not less than a preset requirement), such as splitting or combining them. However, it is difficult to process two beams with similar polarization characteristics or without fixed polarization characteristics. In contrast, the optical antenna in this embodiment processes beams based on their energy distribution. Therefore, even if the polarization characteristics of the first and second beams are similar, as long as their energy distributions are different, the first and second beams can be split or combined relatively well.

[0072] The optical antenna in this embodiment can perform beam processing, such as beam combining or splitting, on the first and second beams by utilizing the energy distribution of the beams, without relying on the wavelength or polarization characteristics of the beams. Furthermore, the optical antenna reflects the first beam in the reflection region where the first beam's energy is concentrated, and transmits the second beam in the transmission region where the second beam's energy is concentrated, allowing for more targeted transmission and reflection, thus reducing energy loss after the beam passes through the optical elements. The optical antenna also eliminates the need for additional components, therefore, it has a wide range of applications and does not increase the size or complexity of the optical path.

[0073] In practical applications, the space link requirement is usually identified first, and then an optical antenna is designed based on that requirement. The process of designing an optical antenna involves gradually optimizing its parameters until the antenna parameters meet various performance requirements. In this embodiment, the antenna parameters that need to be optimized include the energy distribution parameters of the first light source component 10, the energy distribution parameters of the second light source component 40, the position of the reflection area, the position of the transmission area, the reflectivity of the reflection area, and the transmittance of the projection area.

[0074] In practical applications, the general process of designing optical antennas based on space link requirements is as follows:

[0075] Determine the initial antenna parameters based on the preset space link requirements;

[0076] Based on the antenna parameters, simulate the working process of the optical antenna, that is, simulate the process of the optical antenna transmitting and receiving data under this set of antenna parameters;

[0077] Based on the performance characterization data obtained from the simulation, determine the index value of at least one performance index of the optical antenna, wherein at least one performance index is such as transmission efficiency, reception efficiency, etc.

[0078] If it is determined that the value of any performance index does not meet the requirements of that performance index, then at least one parameter in the antenna parameters shall be adjusted.

[0079] The process involves simulating the operation of the optical antenna according to its parameters until the values ​​of various performance indicators meet the requirements of their respective performance indicators. At this point, the current antenna parameters are considered the final antenna parameters. In other words, the optical antenna design can be completed when the values ​​of each performance indicator meet the requirements for that specific performance indicator.

[0080] Then, the antenna can be manufactured according to the antenna parameters obtained from the design.

[0081] Based on the same inventive concept, this application also provides a communication terminal 70', see [link to relevant documentation]. Figure 7 , Figure 7 The schematic diagram of a communication terminal 70' provided in this application embodiment includes: an optical antenna 71, a low-noise amplifier 72, a wavelength divider 73, a first wavelength conversion component 74, an optical amplifier 75, a wavelength multiplexer 76, and a second wavelength conversion component 77. The optical antenna 71 can adopt the structure of the optical antenna 300 or the optical antenna 400 described above, and is used to receive and transmit optical signals. The low-noise amplifier 72 is used to amplify the optical signal received by the optical antenna 71 and send it to the wavelength divider 73. The wavelength divider 73 is used to filter the received optical signal, forming optical control messages and optical data messages. The optical control message is sent to the subsequent switching control unit for processing, and the optical data message is sent to the second switching control unit for processing. The data is sent to the first wavelength conversion component 74; the first wavelength conversion component 74 is used to convert the wavelength of the optical data packet and send the converted optical data packet to the subsequent optical switching unit for processing; the second wavelength conversion component 77 is used to convert the wavelength of the optical data packet to be transmitted sent by the optical switching unit and send the converted optical data packet to the multiplexer 76; the multiplexer 76 is used to combine the optical control message to be transmitted sent by the switching control unit and the optical data packet to be transmitted to form the optical signal to be transmitted, and send the optical signal to be transmitted to the optical amplifier 75; the optical amplifier 75 is used to amplify the optical signal to be transmitted and send it to the optical antenna 71 for external transmission.

[0082] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0083] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, then this application also includes such modifications and variations.

Claims

1. An optical antenna, characterized in that, Includes a first light source assembly and optical elements, wherein: The first light source assembly is used to emit a first light beam toward the optical element; The optical element includes a reflective region for reflecting the first light beam, and the reflective region covers the central region of the first light spot formed by the first light beam on the optical element. The optical element further includes a transmission region for transmitting a second light beam, the second light beam being an external light beam received by the optical antenna; or, the optical antenna further includes a second light source assembly that emits the second light beam toward the optical element; the transmission region covers the central region of the second light spot formed by the second light beam on the optical element; the energy distributions of the second light beam and the first light beam are different, causing the first light spot and the second light spot to partially overlap, or, the first light spot is located inside the second light spot and their central regions do not coincide, or, the second light spot is located inside the first light spot and their central regions do not coincide; The optical element is used to combine the first beam and the second beam through the reflection region and the transmission region.

2. The optical antenna as described in claim 1, characterized in that, The reflective area is also used to reflect external light beams received by the optical antenna; The optical element is also used to split the external light beam received by the optical antenna through the reflection region and the transmission region.

3. The optical antenna as described in claim 1 or 2, characterized in that, The surface of the reflective area facing the first light source component is coated with a reflective film; When the second beam is an external beam received by the optical antenna, the surface of the transmission region facing the second light source component is coated with a transmission film; when the second beam is a beam emitted by the second light source component, the opposite two surfaces of the transmission region are coated with transmission films.

4. The optical antenna as described in claim 1 or 2, characterized in that, The reflecting area is a reflector, and the transmitting area is an intensifying lens.

5. The optical antenna as described in claim 1 or 2, characterized in that, The surface of the reflective area facing the first light source assembly is coated with a reflective film, or the reflective area is a reflective mirror; The transmission area is hollowed out.

6. The optical antenna as described in claim 1 or 2, characterized in that, The reflective area has a reflective film coated on the side of the surface facing the first light source component, and the transmission area is an intensifying lens, or; The reflecting area is a reflector. When the second beam is an external beam received by the optical antenna, the surface of the transmission area facing the second light source component is coated with a transmission film. When the second beam is a beam emitted by the second light source component, the opposite two surfaces of the transmission area are coated with transmission films.

7. The optical antenna as claimed in claim 1, characterized in that, The difference between the wavelengths of the first beam and the second beam is less than a preset value.

8. The optical antenna as claimed in claim 1, characterized in that, The difference in polarization characteristics between the first beam and the second beam is less than a preset requirement.

9. A communication terminal, characterized in that, Includes the optical antenna as described in any one of claims 1 to 8.

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