Light emitting device and related equipment

Abstract

A light emitting device and related equipment, the light emitting device comprising a light source for emitting a first light beam to the lens module, the first light beam being a Gaussian beam, the lens module for collimating the first light beam to form a second light beam, the equivalent Rayleigh distance of the second light beam being related to the first distance and the second distance, wherein the first distance is the distance between the lens module and the waist position of the first light beam, and the second distance is the focal length of the lens module. When the first distance is greater than or equal to 0 and the second distance is 0.48-3 times of the Rayleigh distance of the first light beam, the equivalent Rayleigh distance of the light beam generated by the light emitting device can be increased, the divergence of the light beam is reduced, and the receiving power of the light beam is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical communication technology, and specifically to a light emitting device and related equipment. Background Art

[0002] Wireless optical communication technology is a wireless communication technology that uses light waves to transmit information. Compared with traditional electromagnetic wave communication, it has higher frequencies and narrower beams, which can provide higher bandwidth and more secure data transmission while reducing interference with other devices.

[0003] Wireless optical communications are mainly based on Gaussian beams propagating in free space. The position where the Gaussian beam is transmitted absolutely parallel is its beam waist position. In addition, the Gaussian beam also has a Rayleigh distance, which refers to the distance from its beam waist position to a cross-section with an area twice the waist area along the direction of its travel.

[0004] However, since light diverges due to diffraction during propagation, when the transmission length of a light beam exceeds its Rayleigh distance, the power loss of the light beam is large, and part of the light energy cannot reach the detector at the receiving end. Summary of the Invention

[0005] An embodiment of the present application provides a light emitting device for reducing the divergence of a light beam and improving the receiving power of the light beam. An embodiment of the present application also provides a corresponding light emitting module, optical communication equipment, an optical communication system, a laser radar, etc.

[0006] In a first aspect, the present application provides a light emitting device, which includes a light source and a lens module; the light source is used to emit a first light beam to the lens module, and the first light beam is a Gaussian beam; the lens module is used to collimate the first light beam to form a second light beam, and the equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance, the first distance is the distance between the lens module and the waist position of the first light beam, and the second distance is the focal length of the lens module; the first distance is greater than or equal to 0, and the second distance is 0.48 times to 3 times the Rayleigh distance of the first light beam.

[0007] In the present application, the light source includes a light-emitting device and a signal adjustment module. The signal modulation module is used to determine the Gaussian beam emitted by the light source. The signal modulation module may include a signal modulation unit, a data signal interface, and a data source connected to the interface, wherein the data in the data source is sent to the signal modulation unit through the data signal interface, and the signal modulation unit determines the Gaussian beam emitted by the light source based on the data.

[0008] The lens module in this application includes one or more convex or concave lenses, including at least one convex lens. The equivalent focal length formed by the multiple convex or concave lenses is the focal length of the lens module, i.e., the second distance. The first distance is the distance between the waist position of the first light beam and the lens in the lens module closest to the waist position.

[0009] In this application, the equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance, that is, by adjusting the first distance and / or the second distance, the equivalent Rayleigh distance of the light beam generated by the light emitting device can be adjusted accordingly. The goal is to maximize the equivalent Rayleigh distance of the light beam generated by the light emitting device, so that the light beam emitted by the light emitting device does not diverge as much as possible, and reduces the energy lost after it is received.

[0010] In this first aspect, a light emitting device includes a light source and a lens module. The light source is configured to emit a first light beam to the lens module, wherein the first light beam is a Gaussian beam. The lens module is configured to collimate the first light beam to form a second light beam. The equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance, wherein the first distance is the distance between the lens module and the beam waist of the first light beam, and the second distance is the focal length of the lens module. When the first distance is greater than or equal to 0 and the second distance is between 0.48 and 3 times the Rayleigh distance of the first light beam, the equivalent Rayleigh distance of the light beam generated by the light emitting device can be increased, thereby reducing the divergence of the light beam and improving the received power of the light beam.

[0011] In a possible implementation manner of the first aspect, the lens module includes a first convex lens, and the first distance is less than or equal to 10 times the lens aperture of the first convex lens.

[0012] In this possible implementation, the lens module includes only one convex lens, and the value of the first distance has little effect on the equivalent Rayleigh distance. The smaller the first distance, the smaller the lens aperture of the first convex lens, which can reduce the production difficulty of the first convex lens. Therefore, the first distance is less than or equal to 10 times the lens aperture of the first convex lens.

[0013] In a possible implementation manner of the first aspect, the first distance is 0.

[0014] In this possible implementation, the first convex lens is placed at the waist of the first light beam to minimize the lens aperture of the first convex lens and maximize the compact integration of the entire light emitting device. The equivalent Rayleigh distance is maximized only by adjusting the second distance.

[0015] In a possible implementation of the first aspect, the lens module further includes at least one superimposed lens, the at least one superimposed lens is a convex lens or a concave lens, and the focal length of the lens module is an equivalent focal length of the at least one superimposed lens and the first convex lens.

[0016] In this possible implementation, the second distance required by the light emitting device may be too large to be met by a single convex lens. Therefore, at least one superimposed lens may be added to the first convex lens to achieve a longer focal length through a telescope system.

[0017] In a possible implementation of the first aspect, a distance between the first convex lens and the first superimposed lens is greater than a first threshold and less than a second threshold, the first superimposed lens is the superimposed lens closest to the first convex lens in the lens module, the first threshold is the maximum value of the focal length of the first convex lens and the focal length of the first superimposed lens, and the second threshold is the sum of the focal length of the first convex lens and the focal length of the first superimposed lens.

[0018] In this possible implementation, when the distance between the first convex lens and the first superimposed lens is greater than the maximum value of the focal length of the first convex lens and the focal length of the first superimposed lens, and less than the sum of the focal length of the first convex lens and the focal length of the first superimposed lens, the equivalent focal length of the first convex lens and the first superimposed lens can reach a larger value to meet the requirements of the light emitting device.

[0019] In a possible implementation manner of the first aspect, the light emitting device further includes an adjustment module, configured to adjust a distance between the at least one superimposed lens and the first convex lens to change the second distance.

[0020] In this possible implementation, based on the adjustment module, when the Gaussian light beam emitted by the light source changes, the second distance can be adjusted accordingly to keep the equivalent Rayleigh distance of the light beam generated by the light emitting device at the maximum, thereby minimizing the energy loss of the light beam.

[0021] In a possible implementation manner of the first aspect, the adjustment module is further configured to adjust a position of the first convex lens to change the first distance.

[0022] In this possible implementation, based on the adjustment module, when the Gaussian light beam emitted by the light source changes, the first distance can be adjusted accordingly to keep the equivalent Rayleigh distance of the light beam generated by the light emitting device at the maximum, thereby minimizing the energy loss of the light beam.

[0023] A second aspect of the present application provides an optical transmission module, which includes an optical transmission device as described in the first aspect or any possible implementation of the first aspect, and a signal modulation module coupled to the optical transmission device.

[0024] A third aspect of the present application provides an optical communication device, which includes a light emitting device as described in the first aspect or any possible implementation of the first aspect, and a signal modulation module coupled to the light emitting device.

[0025] A fourth aspect of the present application provides an optical communication system, which includes an optical emitting device and an optical receiving device as described in the first aspect or any possible implementation of the first aspect, wherein the optical receiving device is used to receive an optical signal emitted by the optical emitting device.

[0026] A fifth aspect of the present application provides a laser radar, which includes a light emitting device as described in the first aspect or any possible implementation of the first aspect.

[0027] In an embodiment of the present application, a light emitting device includes a light source and a lens module. The light source is configured to emit a first light beam to the lens module. The first light beam is a Gaussian beam. The lens module is configured to collimate the first light beam to form a second light beam. The equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance, wherein the first distance is the distance between the lens module and the beam waist of the first light beam, and the second distance is the focal length of the lens module. When the first distance is greater than or equal to 0 and the second distance is between 0.48 and 3 times the Rayleigh distance of the first light beam, the equivalent Rayleigh distance of the light beam generated by the light emitting device can be increased, thereby reducing the divergence of the light beam and improving the received power of the light beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the Rayleigh distance of a Gaussian beam;

[0029] Figure 2 A schematic diagram of the architecture of the transmitter optical system provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of an embodiment of a light emitting device provided in an embodiment of the present application;

[0031] Figure 4 A schematic diagram of another embodiment of a light emitting device provided in an embodiment of the present application;

[0032] Figure 5 A schematic diagram of another embodiment of a light emitting device provided in an embodiment of the present application;

[0033] Figure 6 A schematic diagram comparing the effects before and after using the light emitting device provided in an embodiment of the present application;

[0034] Figure 7 A schematic diagram of an embodiment of an optical communication system provided in an embodiment of the present application;

[0035] Figure 8 Schematic diagram of an embodiment of the laser radar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present application, rather than all the embodiments. Those skilled in the art will appreciate that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0037] The terms "first," "second," and the like in the specification and claims of this application and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0038] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0039] In addition, numerous specific details are provided in the detailed description below to better illustrate the present application. Those skilled in the art will appreciate that the present application can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0040] The following examples illustrate the application scenarios involved in the embodiments of the present application.

[0041] Wireless optical communication technology is a wireless communication technology that uses light waves to transmit information. Compared with traditional electromagnetic wave communication, it has higher frequencies and narrower beams, which can provide higher bandwidth and more secure data transmission while reducing interference with other devices.

[0042] like Figure 1 As shown in the figure, wireless optical communication is mainly based on Gaussian beams propagating in free space. The amplitude distribution of the cross section of the Gaussian beam follows the Gaussian function. The position where the Gaussian beam is absolutely parallel to the beam waist is the beam waist position. In addition, the Gaussian beam has a Rayleigh distance z0, which can also be called the Rayleigh length or Rayleigh range. The Rayleigh distance refers to the distance from the beam waist position to the cross section with an area twice the waist area along the direction of the beam's travel. At this time, the cross section radius is approximately times the waist radius.

[0043] The Rayleigh distance of a Gaussian beam propagating in free space is Where λ is the wavelength of the beam, w0 is the waist radius, that is, the axial radius of the narrowest part of the beam. Assuming that the waist of the beam is not particularly small, w0 ≥ 2λ / π.

[0044] However, since light diverges due to diffraction during propagation, when the transmission length of a light beam exceeds its Rayleigh distance, the power loss of the light beam is relatively large. Even if the receiving end and the transmitting end of the light beam are aligned, part of the light energy cannot reach the detector at the receiving end.

[0045] Based on this, embodiments of the present application provide a light emitting device for reducing the divergence of a light beam and improving the received power of the light beam. Embodiments of the present application also provide corresponding light emitting modules, optical communication equipment, optical communication systems, and laser radars. These are described in detail below.

[0046] like Figure 2 As shown, the optical emitting device provided in the embodiment of the present application is used in the transmitter optical system of wireless optical communication. The incident light beam is generally generated by a light source and incident on the lens module. After optical transformation, it is emitted into free space as an optical signal and received and processed by a remote receiving system. The transmitter optical system here may be an optical wireless base station or an optical backhaul station. In addition to the light-emitting device, the light source generally also includes a signal modulation unit, a data signal interface, and a data source connected to the interface.

[0047] The light emitting device provided in the embodiment of the present application is described below in conjunction with the above application scenarios.

[0048] like Figure 3 As shown, an embodiment of the present application provides a light emitting device, which includes a light source 100 and a lens module 200 .

[0049] In which, the light source 100 is used to emit a first light beam to the lens module 200, and the first light beam is a Gaussian beam; the lens module 200 is used to collimate the first light beam to form a second light beam, and the equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance. The first distance is the distance between the lens module 200 and the waist position of the first light beam, and the second distance is the focal length of the lens module 200; the first distance is greater than or equal to 0, and the second distance is 0.48 times to 3 times the Rayleigh distance of the first light beam.

[0050] It should be understood that Figure 3 The light emitting device shown is only a schematic diagram. In actual situations, the lens module is not packaged separately or together with the light source. The embodiment of the present application does not limit the specific structure of the lens module.

[0051] Specifically, the lens module may include multiple lenses, which are described in detail below.

[0052] 1. First Convex Lens

[0053] like Figure 4 As shown, when the lens module only includes the first convex lens, the first light beam passes through the first convex lens and becomes the second light beam. The focal length of the first convex lens, that is, the second distance is F, the distance between the waist position of the first light beam and the first convex lens, that is, the first distance is l, and the distance between the waist position of the second light beam and the first convex lens is l. c , the waist radius of the first beam is w0, the waist radius of the second beam is w′0, the Rayleigh distance of the first beam is z0, and the Rayleigh distance of the second beam is z′0. According to optical theory, we have:

[0054]

[0055]

[0056]

[0057] After the first beam passes through the first convex lens, the second beam converges and then diverges to a position z′0 away from the waist position of the second beam. The area of ​​the second beam expands to twice its original size. The equivalent Rayleigh distance z of the second beam is:

[0058] z=l c +z′0

[0059] in,

[0060]

[0061] Substituting the formula in optical theory, we can get:

[0062]

[0063] It can be seen that the equivalent Rayleigh distance z of the second light beam is related to the first distance l and the second distance F. Therefore, the above formula can be used as a constraint function to determine the values ​​of the first distance l and the second distance F when z is the maximum value by taking derivatives or using computing equipment. When the first distance is greater than or equal to 0 and the second distance is 0.48 to 3 times the Rayleigh distance z0 of the first light beam, the equivalent Rayleigh distance z of the second light beam can be made larger, thereby reducing the divergence of the light beam and improving the received power of the light beam.

[0064] It should be understood that the Rayleigh distance z′0 of the second light beam and the equivalent Rayleigh distance z of the second light beam are two different concepts. The Rayleigh distance z′0 of the second light beam is the Rayleigh distance of the second light beam itself, while the equivalent Rayleigh distance z of the second light beam can be understood as the equivalent Rayleigh distance of the light beam generated by the light emitting device. The Rayleigh distance z′0 of the second light beam plus the distance l between the waist position of the second light beam and the first convex lens is c After that, it is the equivalent Rayleigh distance z of the second beam, that is, z = l c +z′0.

[0065] Optionally, practice has found that the value of the first distance l has little effect on the equivalent Rayleigh distance z, and the smaller the first distance l is, the smaller the lens aperture of the first convex lens is, which can reduce the production difficulty of the first convex lens. Therefore, the first distance l is less than or equal to 10 times the lens aperture of the first convex lens.

[0066] For example, when the lens diameter of the first convex lens is 1 cm, the value range of the first distance l is 0 to 10 cm.

[0067] Optionally, the first distance l is 0, that is, the first convex lens is placed at the waist position of the first light beam, then:

[0068]

[0069] When the first distance l is 0, the lens aperture of the first convex lens is minimized and the compact integration of the entire light emitting device is maximized. Only by adjusting the second distance F, the equivalent Rayleigh distance z is maximized.

[0070] For example, the first distance l is 0, and the lens aperture of the first convex lens can be controlled to be 1 cm. Compared with the lens aperture of 10 cm, the first convex lens at this time has lower cost, lighter weight, smaller volume, and is more convenient to assemble.

[0071] Optionally, in a possible implementation, the second distance F further satisfies the following formula to maximize the equivalent Rayleigh distance z:

[0072]

[0073] Optionally, taking into account the problem of implementation error, when determining that z is the maximum value, the values ​​of the first distance l and the second distance F obtained can also be adjusted according to the error. For example, for the second distance F, the obtained value can be further adjusted within the range of plus or minus 0.1 meters.

[0074] 2. Combination of the First Convex Lens and the Superimposed Lens

[0075] Based on the first scenario above, the calculated second distance F may be too large to be achieved with a single convex lens. Therefore, at least one superimposed lens can be added to the first convex lens to achieve a longer focal length through the telescope system. Each of the at least one superimposed lens can be all convex, all concave, or a combination of convex and concave lenses. In this case, the focal length of the lens module, i.e., the second distance, is the equivalent focal length of the at least one superimposed lens and the first convex lens.

[0076] For example, Figure 5 As shown, the lens module 200 includes a first convex lens 201 and a first superimposed lens 202. The focal length of the first convex lens 201 is F1, the focal length of the first superimposed lens 202 is F2, the distance between the first convex lens 201 and the first superimposed lens 202 is d, and the equivalent focal length of the first convex lens 201 and the first superimposed lens 202, that is, the focal length of the lens module 200, that is, the second distance is f. According to the combined lens equation:

[0077]

[0078] In order to make f larger, the distance d between the first convex lens 201 and the first superimposed lens 202 is greater than a first threshold and less than a second threshold, the first threshold is the maximum value max(F1, F2) of the focal length of the first convex lens 201 and the focal length of the first superimposed lens 202, and the second threshold is the sum of the focal length of the first convex lens 201 and the focal length of the first superimposed lens 202 F1+F2.

[0079] Optionally, the lens module may include three or more lenses. In this case, the first superimposed lens is the superimposed lens closest to the first convex lens in the lens module. The first convex lens and the first superimposed lens can be combined into an equivalent lens, and then the added lens can calculate the new phase according to the above formula. This continues until all lenses are considered and the overall equivalent focal length is calculated. The overall equivalent focal length is the second distance.

[0080] It should be understood that the lens module should include at least one convex lens, that is, at least a first convex lens, on which basis other convex lenses or concave lenses can be superimposed, wherein the focal length of the convex lens is greater than 0, while the focal length of the concave lens is less than 0.

[0081] Optionally, the light emitting device further includes an adjustment module configured to adjust the spacing between at least one superimposed lens and the first convex lens to change the second distance. Furthermore, the adjustment module can also be configured to adjust the position of the first convex lens to change the first distance. Based on this adjustment module, when the Gaussian beam emitted by the light source changes, the first and second distances can be adjusted accordingly to maximize the equivalent Rayleigh distance of the light beam generated by the light emitting device, thereby minimizing energy loss in the beam.

[0082] Exemplarily, the adjustment module is a bracket for fixing the first convex lens and at least one first superimposed lens, and the distance between the at least one superimposed lens and the first convex lens is adjusted by moving the bracket, or the position of the first convex lens is adjusted separately.

[0083] like Figure 6 As shown, in the 1550nm band, with a 10cm emission aperture, the original Rayleigh distance is 5068m and remains unchanged. By using the light emitting device provided in the embodiment of the present application and superimposing a lens module with an equivalent focal length of 2408m, the equivalent Rayleigh distance will exceed the original value. The optimal equivalent focal length, i.e., the second distance, is F = 6972.7m, as marked by the dotted line, at which point the equivalent Rayleigh distance reaches 7167m.

[0084] In an embodiment of the present application, a light emitting device includes a light source and a lens module. The light source is configured to emit a first light beam to the lens module. The first light beam is a Gaussian beam. The lens module is configured to collimate the first light beam to form a second light beam. The equivalent Rayleigh distance of the second light beam is related to the first distance and the second distance, wherein the first distance is the distance between the lens module and the beam waist of the first light beam, and the second distance is the focal length of the lens module. When the first distance is greater than or equal to 0 and the second distance is between 0.48 and 3 times the Rayleigh distance of the first light beam, the equivalent Rayleigh distance of the light beam generated by the light emitting device can be increased, thereby reducing the divergence of the light beam and improving the received power of the light beam.

[0085] The above introduces the light emitting device provided in the embodiment of the present application. The following introduces the related equipment provided in the embodiment of the present application with reference to the accompanying drawings.

[0086] like Figure 7 As shown, in another embodiment of the present application, a light transmitting module is also provided, which includes the above Figures 3 to 6 Some embodiments describe a light emitting device and a signal modulation module coupled to the light emitting device.

[0087] The signal modulation module is used to determine the Gaussian beam emitted by the light source. The signal modulation module may include a signal modulation unit, a data signal interface, and a data source connected to the interface, wherein the data in the data source is sent to the signal modulation unit through the data signal interface, and the signal modulation unit determines the Gaussian beam emitted by the light source based on the data.

[0088] The optical transmission module may correspond to Figure 2 The light source and lens modules in the system shown.

[0089] Refer to Figure 7 In another embodiment of the present application, an optical communication device is also provided, the optical communication device comprising the above Figures 3 to 6Some embodiments describe a light emitting device and a signal modulation module coupled to the light emitting device.

[0090] The optical communication device may include the above-mentioned optical transmission module, and the optical communication device may also correspond to Figure 2 An optical wireless base station or optical backhaul station in the system shown.

[0091] Refer to Figure 7 In another embodiment of the present application, an optical communication system is also provided, which includes the above Figures 3 to 6 Some embodiments describe a light emitting device and a signal modulation module coupled to the light emitting device.

[0092] The optical communication system may include the above-mentioned optical communication device or optical transmission module, and also includes a remote receiving device. The optical communication system may also correspond to Figure 2 The system shown.

[0093] In another embodiment of the present application, a laser radar is also provided, which includes the above-mentioned Figures 3 to 6 Some embodiments describe light emitting devices.

[0094] like Figure 8 As shown, the laser radar can be used in the automotive field, that is, installed on the vehicle for scenarios such as autonomous driving or risk identification. At this time, the Gaussian beam generated by the light source in the optical emitting device may not contain a modulated signal.

[0095] In the several embodiments provided in this application, it should be understood that the disclosed structures can be implemented in other ways. For example, the embodiments described above are merely illustrative. For example, the division of the structure described can be divided in other ways in actual implementation, such as multiple units or components can be combined or integrated into another structure, or some features can be ignored. Some or all of the structures can be selected according to actual needs to achieve the purpose of the present embodiment.

[0096] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A light emitting device, characterized in that: including a light source and a lens module; The light source is used to emit a first light beam to the lens module, and the first light beam is a Gaussian light beam; The lens module is used to collimate the first light beam to form a second light beam, the equivalent Rayleigh distance of the second light beam is related to a first distance and a second distance, the first distance is the distance between the lens module and the waist position of the first light beam, and the second distance is the focal length of the lens module; The first distance is greater than or equal to 0, and the second distance is 0.48 times to 3 times the Rayleigh distance of the first light beam.

2. The device according to claim 1, characterized in that The lens module includes a first convex lens, and the first distance is less than or equal to 10 times of a lens diameter of the first convex lens.

3. The device according to claim 1 or 2, characterized in that The first distance is 0.

4. The device according to claim 2 or 3, characterized in that The lens module further includes at least one superimposed lens, the at least one superimposed lens is a convex lens or a concave lens, and the focal length of the lens module is an equivalent focal length of the at least one superimposed lens and the first convex lens.

5. The device according to claim 4, characterized in that A distance between the first convex lens and the first stacking lens is greater than a first threshold and less than a second threshold. The first stacking lens is the stacking lens closest to the first convex lens in the lens module. The first threshold is the maximum value of the focal length of the first convex lens and the focal length of the first stacking lens. The second threshold is the sum of the focal length of the first convex lens and the focal length of the first stacking lens.

6. The device according to claim 4 or 5, characterized in that An adjustment module is also included, and the adjustment module is used to adjust the distance between the at least one superimposed lens and the first convex lens to change the second distance.

7. The device according to claim 6, characterized in that The adjustment module is further used to adjust the position of the first convex lens to change the first distance.

8. An optical transmission module, characterized in that: The method comprises a light emitting device as claimed in any one of claims 1 to 7, and a signal modulation module coupled to the light emitting device.

9. An optical communication device, characterized in that: The method comprises a light emitting device as claimed in any one of claims 1 to 7, and a signal modulation module coupled to the light emitting device.

10. An optical communication system, characterized in that: The optical transmission device comprises the optical transmission device and the optical reception device as claimed in any one of claims 1 to 7, wherein the optical reception device is used to receive the optical signal transmitted by the optical transmission device.

11. A laser radar, characterized in that: Comprising the light emitting device as claimed in any one of claims 1 to 7.

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