Optical fiber close-packed structure, radar transmitting and receiving device and laser radar system

Abstract

The invention relates to an optical fiber close-packed structure, a radar transmitting and receiving device and a laser radar system, which are applied to a laser radar, the optical fiber close-packed structure comprises two substrates which are stacked up and down, and the opposite surfaces of the two substrates form an accommodating space; a V-shaped groove is formed in at least one side wall surface of the accommodating space, the V-shaped groove is used for placing coupling optical fibers, the adjacent coupling optical fibers form an optical fiber group, and the transverse distance between the adjacent coupling optical fibers in the optical fiber group is smaller than or equal to the diameter of a fiber core; at least two optical fiber groups are arranged in the accommodating space, a distance exists between different optical fiber groups, and each optical fiber group forms a detection range. According to the invention, each optical fiber group has small vertical angle resolution, the light-emitting angle density of the laser radar is increased, the plurality of optical fiber groups respectively form a detection range, each detection range corresponds to a light-sensitive surface of one receiving detector, the number of the receiving detectors is reduced, and the design cost is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of laser radar technology, and in particular to a densely packed optical fiber structure, a radar transceiver, and a laser radar system. Background Art

[0002] In a multi-line lidar, the angle between two adjacent beams is the lidar's vertical angular resolution. Vertical angular resolution is crucial for long-range target detection and identification. A lower vertical resolution allows for more points and a more detailed image to be captured on the target. Related technologies achieve different vertical angle distributions by adjusting the spacing of the lasers or the arrangement of the coupling fibers. However, this also suffers from insufficient angular density. Summary of the Invention

[0003] In order to solve at least one of the technical problems mentioned above, the present disclosure proposes a densely packed optical fiber structure, a radar transceiver, and a laser radar system.

[0004] According to some embodiments of the present disclosure, a close-packed optical fiber structure is provided for use in a laser radar, wherein the close-packed optical fiber structure includes two substrates stacked one above the other, and opposite surfaces of the two substrates form an accommodating space; a V-groove is provided on at least one side wall of the accommodating space, and the V-groove is used to place coupled optical fibers, and adjacent coupled optical fibers form an optical fiber group, and the lateral spacing between adjacent coupled optical fibers in an optical fiber group is less than or equal to a core diameter; at least two optical fiber groups are arranged in the accommodating space, and there is a spacing between different optical fiber groups, and each optical fiber group forms a detection range.

[0005] Based on the above scheme, the optical fiber close-packed structure includes multiple optical fiber groups, each optical fiber group includes multiple adjacent coupled optical fibers, and the lateral spacing between adjacent coupled optical fibers is less than or equal to the core diameter, that is, each optical fiber group has a small vertical angular resolution, which increases the luminous angle density of the laser radar. Multiple optical fiber groups form detection ranges respectively, and each detection range can correspond to the photosensitive surface of a receiving detector, thereby reducing the number of receiving detectors and thus reducing design costs. In addition, the optical fiber close-packed structure realized by multiple V-grooves has an overall structure that is convenient for debugging and assembly.

[0006] In some possible embodiments, the optical fiber group is a first optical fiber group or a second optical fiber group; the first optical fiber group includes at least one coupling optical fiber, and the coupling optical fibers of the first optical fiber group are arranged in a single layer in parallel, one side wall of the accommodating space is provided with a V-groove, and the other side wall is provided with a plane, the V-groove of one side wall and the plane of the other side wall form a first groove group, and the first groove group is used to place the first optical fiber group; the second optical fiber group includes at least three coupling optical fibers, and the coupling optical fibers of the second optical fiber group are arranged in a double layer in an staggered manner, and the two side walls of the accommodating space are respectively provided with parallel V-grooves, and the V-grooves of the two side walls are staggered and opposite, and the V-grooves of the two side walls form a second groove group, and the second groove group is used to place the second optical fiber group.

[0007] Based on the above scheme, the coupling fiber structure of the first fiber group is a single-layer parallel arrangement with a lateral spacing equal to one core diameter, while the coupling fiber structure of the second fiber group is a double-layer staggered arrangement with a lateral spacing less than one core diameter. The first fiber group and the second fiber group correspond to different vertical angular resolutions, respectively. By setting different first fiber groups and second fiber groups, the debugging difficulty of the laser radar when detecting objects with different precision requirements can be reduced, thereby improving the compatibility and flexibility of the laser radar.

[0008] In some possible implementations, the groove angle of the V-groove in the second groove group is 60°, the two layers of coupled optical fibers in the second optical fiber group are staggered and tangent to each other, and three adjacent coupled optical fibers are tangent to each other in pairs.

[0009] Based on the above solution, the lateral spacing of the coupled optical fibers of the second optical fiber group is equal to one fiber core radius, and the corresponding luminous angle density is twice that of the first optical fiber group. In addition, the two layers of coupled optical fibers of the second optical fiber group are staggered and tangent, which can reduce the lateral length of the second optical fiber group, making the laser beam more concentrated, and the corresponding laser radar detection accuracy is also greater.

[0010] In some possible embodiments, the optical fiber close-packed structure includes at least three substrates, which are stacked up and down, and a accommodating space is formed between every two adjacent substrates. At least one optical fiber group is arranged in each accommodating space.

[0011] Based on the above solution, a row of optical fiber groups is provided in the accommodating space between each two substrates. Multiple substrates form multiple accommodating spaces. Multiple optical fiber groups in each accommodating space form a denser detection range, and multiple optical fiber groups can be arranged in two dimensions, which can meet the complex detection requirements of the laser radar.

[0012] In some possible implementations, the lateral distances between adjacent coupled optical fibers in the optical fiber group are consistent, and the minimum lateral distance between adjacent optical fiber groups is equal to the lateral distance between adjacent coupled optical fibers in the optical fiber group.

[0013] Based on the above solution, the lateral distances between adjacent coupled optical fibers of two adjacent optical fiber groups remain consistent, thereby making the luminous angles of the coupled optical fibers of the two adjacent optical fiber groups continuous and uniform.

[0014] According to some other embodiments of the present disclosure, a radar transceiver is provided, including a transmitting module and a receiving module, wherein the transmitting module is used to transmit a laser beam, the transmitting module includes a driving board and an optical fiber close-packed structure according to any one of the above embodiments, the driving board includes a light source and a driving circuit, and the driving board is connected to the optical fiber close-packed structure via a coupling optical fiber; the receiving module is used to receive an echo signal, and the receiving module includes a photodetector.

[0015] In some possible embodiments, the receiving module includes a plurality of the photodetectors, the number of the photodetectors is consistent with the number of optical fiber groups in the optical fiber close-packed structure, the photodetectors correspond one-to-one to the optical fiber groups, and the photosensitive surface area of ​​each photodetector covers the area of ​​the corresponding optical fiber group.

[0016] Based on the above scheme, the photodetectors correspond to the optical fiber groups one by one. One photodetector can receive multiple light rays in one optical fiber group, which can reduce the number of photodetectors, thereby simplifying the structure of the laser radar and reducing the manufacturing cost of the laser radar. The photosensitive surface area of ​​the photodetector covers the area of ​​the optical fiber group, ensuring that the energy of the optical fiber group can be received by the photodetector, thereby improving the accuracy of the laser radar.

[0017] In some possible implementations, the coupling optical fibers belonging to the same optical fiber group emit light at different timings.

[0018] Based on the above solution, the coupled optical fibers of the same optical fiber group cannot emit light at the same time, which can avoid misjudgment when the photoelectric detector receives signals from the same optical fiber group, and can also avoid competitive interference caused by the simultaneous occurrence of signals from the same optical fiber group, thereby ensuring the detection accuracy of the lidar.

[0019] In some possible implementations, the photodetector includes an avalanche photodiode, a silicon photodiode, or a single-photon avalanche diode.

[0020] Based on the above solution, the accuracy of the lidar can be further improved by selecting specific photoelectric detectors.

[0021] According to some other embodiments of the present disclosure, a laser radar system is provided, comprising a radar transceiver device according to any one of the above embodiments.

[0022] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0023] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions and advantages of the embodiments of this specification or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 A schematic diagram showing a close-packed optical fiber structure according to an embodiment of the present disclosure is shown;

[0026] Figure 2 A schematic diagram showing another optical fiber close-packed structure according to an embodiment of the present disclosure;

[0027] Figure 3 A schematic diagram showing a radar transceiver device according to an embodiment of the present disclosure is shown;

[0028] Figure 4 A schematic diagram showing another optical fiber close-packed structure according to an embodiment of the present disclosure;

[0029] Figure 5 A light emission timing diagram of a close-packed optical fiber structure according to an embodiment of the present disclosure is shown;

[0030] Figure 6 A structural diagram of a driving board of a laser radar system according to an embodiment of the present disclosure is shown.

[0031] In the picture:

[0032] 1-driving board; 2-coupling optical fiber; 3-optical fiber close-packed structure; 4-receiving circuit board; 41-photodetector; 5-laser transmitter; 6-fast axis collimating optical fiber. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this invention.

[0034] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0036] 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.

[0037] The term "and / or" herein simply describes an association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent the existence of three situations: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0038] In addition, numerous specific details are provided in the following detailed description to better illustrate the present disclosure. Those skilled in the art will appreciate that the present disclosure 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 points of the present disclosure.

[0039] To facilitate understanding of the present disclosure, some technical terms appearing in the present disclosure are explained or defined below:

[0040] Laser Radar, also known as Laser Radar in English, is a radar system that uses laser beams to detect the position, speed and other characteristic quantities of a target. Its working principle is to transmit a detection signal (laser beam) to the target, and then compare the received signal reflected from the target (target echo) with the transmitted signal. After appropriate processing, relevant information about the target can be obtained, such as target distance, direction, altitude, speed, attitude, and even shape parameters, so as to detect, track and identify the target.

[0041] The vertical angle, also known as the vertical angle or altitude angle, refers to the angle between the sight line and its horizontal line of sight. It is the vertical angle between the central axis of the instrument and the observation point.

[0042] A fiber optic coupler, also known as a splitter, is a component that splits optical signals into multiple optical fibers.

[0043] In lidar, the angle between two adjacent beams is the lidar's vertical angular resolution. This parameter is crucial for long-range detection and target identification. For example, at a range of 100 meters, a vertical angular resolution of 1° can identify an object approximately 1.7 meters tall, while a vertical angular resolution of 0.1° can identify an object approximately 17 centimeters tall. Therefore, a smaller vertical angular resolution, as reflected in the point cloud data, yields more points and a more detailed image of the target object. Therefore, achieving a smaller vertical angular resolution is crucial to improving lidar performance.

[0044] Currently, in multi-line lidars, the main methods for adjusting the vertical angular resolution (or vertical angle distribution) include: adjusting the spacing of the lasers themselves; or, closely arranging the lasers emitted by the lasers through fiber couplers or coupled fibers to generate different beams. Because the design and arrangement of the laser drive circuits can easily lead to larger laser spacing, lidars using fiber coupling solutions have lower vertical angular resolution. The position angle of each fiber after the emitted laser is coupled with the fiber determines the vertical angular resolution. The closely packed coupled fibers are generally formed by photoetching grooves of different angles in a glass substrate, placing the fibers in the grooves, and then fixing them with glue on a cover plate to achieve different luminous angles. The closer the distance between the fibers, the greater the density of luminous angles.

[0045] Related technologies employ a closely packed coupling fiber structure with V-grooves on one side and coupled fibers placed side by side. The center-to-center spacing between adjacent coupled fibers is a minimum of one core diameter, limiting the vertical angular resolution of the light emission and resulting in insufficient angular density. This leads to insufficient LiDAR performance and low detection accuracy. Furthermore, multi-line LiDARs in related technologies require multiple photodetectors corresponding to multiple coupling fibers, increasing the cost of the LiDAR and resulting in a bulky and complex structure.

[0046] To address the aforementioned technical issues, embodiments of the present disclosure provide a close-packed optical fiber structure for use in laser radars (LiDARs) to adjust the exit position of the laser beam emitted by the LiDAR's laser transmitter. V-grooves are provided within the close-packed optical fiber structure to secure the coupled optical fibers. This close-packed optical fiber structure enables the staggered placement of multiple layers of coupled optical fibers, with the minimum lateral distance between coupled optical fibers being one core radius. This increases the angular density of the emitted light and achieves a lower vertical angular resolution.

[0047] In the embodiments of this disclosure, please refer to Figure 1 The optical fiber close-packed structure includes two substrates stacked up and down, and the opposite surfaces of the two substrates form an accommodating space; a V-groove is opened on at least one side wall of the accommodating space, and the V-groove is used to place coupled optical fibers. Adjacent coupled optical fibers form an optical fiber group, and the lateral spacing between adjacent coupled optical fibers in an optical fiber group is less than or equal to one fiber core diameter; at least two optical fiber groups are arranged in the accommodating space, and there is a spacing between different optical fiber groups, and each optical fiber group forms a detection range.

[0048] In the embodiment of the present disclosure, the transverse direction should be understood as the straight length direction where the multiple optical fiber groups are located, rather than being limited to the horizontal direction. That is to say, the embodiment of the present disclosure does not limit the placement angle of the optical fiber close-packed structure. The optical fiber close-packed structure can be placed horizontally, vertically, or at other angles.

[0049] It is worth noting that in the embodiment of the present disclosure, the outer skin (coating) of one end of the coupling optical fiber is removed and then placed in the V-groove, that is, the coupling optical fiber placed in the V-groove is the optical fiber core part, and the above-mentioned lateral spacing between adjacent coupling optical fibers specifically refers to the lateral spacing between adjacent optical fiber cores in the V-groove.

[0050] In addition, it should be noted that in the embodiment of the present disclosure, when the optical fiber group includes more than two layers of coupled optical fibers, that is, V-grooves are avoided on both sides of the accommodating space. At this time, the two adjacent layers of coupled optical fibers are abutted against each other in the vertical direction. That is to say, when the number of layers of coupled optical fibers in the optical fiber group is greater than or equal to 2, the coupled optical fibers are tightly stacked.

[0051] In the embodiment of the present disclosure, the definition of the fiber group is determined by the detection range, that is, one detection range corresponds to one fiber group, which is independent of the number of coupling fibers included in the fiber group. In other words, the fiber group is not limited to including a plurality of coupling fibers. Figure 1 and Figure 2If there is a single coupling fiber with no adjacent coupling fibers on either side (or the adjacent coupling fibers on both sides are far apart), and the single coupling fiber corresponds to a single detection range (or photoelectric sensor), then the single coupling fiber is a fiber group. In addition, unless otherwise specified, the adjacent coupling fibers in the general embodiments of the present disclosure should be understood as transversely adjacent coupling fibers, that is, the coupling fibers with the smallest transverse distance, and the transverse distance is the distance between the central axes of the two coupling fibers in the transverse projection. The embodiments of the present disclosure do not limit the transverse distance of the coupling fibers in the same fiber group, that is, the adjacent coupling fibers in the same fiber group can be tangent or have a spacing.

[0052] In the embodiments of the present disclosure, the purpose of providing a fiber group is to include one or more coupling fibers within the fiber group. When the fiber group includes multiple coupling fibers, the minimum lateral distance between adjacent coupling fibers is less than or equal to one core diameter. In this way, the angle between the light beams emitted by adjacent coupling fibers is smaller, that is, the vertical angular resolution is smaller, and objects of smaller heights can be identified. On the other hand, since adjacent coupling fibers are integrated into a fiber group, a fiber group can emit the same number of light beams as the number of coupling fibers, and each adjacent light beam has an angle. The more bundles, the greater the number of angles that can be set, and the corresponding laser radar has a greater luminous angle density. A greater luminous angle density can enhance the detection performance of the laser radar. For example, when detecting at 100 meters, a vertical angular resolution of 0.1° can identify an object about 17 cm high. If a fiber group includes ten coupling fibers, it can also emit ten light beams, and the angle between adjacent light beams is 0.1°. Then, the fiber group can identify an object 1.7 m away and a feature on the object 17 cm high. Therefore, by integrating multiple coupled fibers into a fiber group and limiting the lateral distance between adjacent coupled fibers within the fiber group, a larger detection range and smaller vertical angular resolution can be achieved simultaneously. It should be understood that the angles between adjacent light rays within a fiber group are not limited to being the same.

[0053] In the embodiment of the present disclosure, there is no restriction on the arrangement structure of the coupling optical fibers within the optical fiber group, that is, the coupling optical fibers within the optical fiber group can be placed side by side in a single layer, or in multiple layers, or in multiple layers staggered. The advantage of stacking the coupling optical fibers is that it can reduce the lateral length of the optical fiber group and thus reduce the volume of the optical fiber close-packed structure, and it can also make the minimum lateral distance of the coupling optical fibers within the optical fiber group less than one core diameter, thereby increasing the luminous angle density and reducing the vertical angular resolution. The embodiment of the present disclosure does not limit the number of layers of coupling optical fibers within the optical fiber group. An optical fiber group can contain only one layer of coupling optical fibers, or it can contain two or more layers of coupling optical fibers. Considering the actual manufacturing situation, the number of layers of coupling optical fibers within the optical fiber group is preferably one or two layers.

[0054] It should be noted that, in general, the lateral spacing between adjacent coupled fibers within a fiber group is fixed, and the corresponding angle between adjacent light beams is also fixed. In some possible implementations, such as when a LiDAR needs to detect objects with irregular or gradient shapes, the lateral spacing between adjacent coupled fibers within a fiber group can be varied.

[0055] In the embodiments of the present disclosure, the fiber optic close-packed structure is not limited to the same fiber optic groups, that is, in a fiber optic close-packed structure, the coupling fiber arrangement structures of different fiber optic groups can be the same or different. Based on the description of the above embodiments, it can be seen that the vertical angular resolution and luminous angle density corresponding to the fiber optic groups of different coupling fiber optic arrangement structures are different. The fiber optic close-packed structure can achieve different laser radar detection requirements by adjusting the number and combination of fiber optic groups. For example, when the overall volume of the target object detected by the laser radar is large, and the laser radar needs to simultaneously detect multiple smaller target features on the target object, then the fiber optic close-packed structure can include multiple identical fiber optic groups, each of which adopts a scheme of placing coupled fibers in multiple layers side by side; when the target object detected by the laser radar has both large-area local features and small-area local features, then the fiber optic close-packed structure can include multiple different fiber optic groups, and different fiber optic groups respectively detect different local features, wherein a fiber optic group with a structure of multiple layers of coupled fibers placed side by side can be used to detect large-area local features, and a fiber optic group with a structure of single layers of coupled fibers placed side by side can be used to detect small-area local features. It should be understood that the design of the fiber group of the densely packed fiber structure is determined by the application scenario and detection requirements of the lidar in which it is located. The above case is for illustrative purposes only and is not the only configuration solution.

[0056] In a further embodiment, the coupled fiber arrangement structures of the fiber groups included in the fiber close-packed structure cannot be completely the same, that is, one fiber close-packed structure includes at least two fiber groups with different coupled fiber arrangement structures.

[0057] Based on the above embodiments, different coupling fiber arrangement structures may have different lateral distances. For example, a close-packed fiber structure includes two fiber groups, wherein one fiber group includes a single layer of coupling fiber, and adjacent coupling fibers abut against each other, and the other fiber group also includes a single layer of coupling fiber, but there is a gap between adjacent coupling fibers. Similarly, the fiber groups within a fiber group can also all have a two-layer coupling fiber structure. In other words, the fiber groups in the close-packed structure have the same hierarchy, and the difference lies in the lateral distances of the coupling fibers in different fiber groups. The close-packed structure under this setting corresponds to an uneven variation in the angular density of radar rays, which can be adapted to the detection of objects with special shapes.

[0058] Based on the above embodiments, different coupling fiber arrangements can also be implemented in different layers. For example, a close-packed fiber structure can include two fiber groups, one of which includes a single layer of coupling fibers, while the other includes multiple layers of coupling fibers. Alternatively, a close-packed fiber structure can include two fiber groups, one of which includes two layers of coupling fibers, while the other includes three layers of coupling fibers. Based on this arrangement, the lateral distances between adjacent coupling fibers in different fiber groups can be set to be consistent, thereby ensuring a uniform angular density variation.

[0059] In further embodiments, please refer to Figure 1 and Figure 2 A close-packed optical fiber structure includes at least one optical fiber group with a single-layer coupled optical fiber arrangement and at least one optical fiber group with a multi-layer coupled optical fiber arrangement, wherein the optical fiber group with the multi-layer coupled optical fiber arrangement includes at least two layers of coupled optical fibers. Based on this arrangement, the optical fiber groups in the close-packed optical fiber structure can be prevented from having a single structure. The comprehensive detection performance of the lidar can be enhanced by using optical fiber groups with different structures. For example, the lidar can simultaneously detect objects at different distances based on optical fiber groups with different structures; alternatively, the lidar can simultaneously detect objects at different resolutions based on optical fiber groups with different structures.

[0060] Based on the above embodiments, it can be seen that one optical fiber group corresponds to one detection range, and the embodiments of the present disclosure do not limit the definition of the detection range. The detection range can be understood as an independent light spot range formed by the light emitted by the optical fiber group; it can also be understood as follows: there is an independent photoelectric detector or an independent receiving module in the laser radar, which is used to receive the reflected light emitted by the optical fiber group on the object.

[0061] It should be noted that the embodiments of the present disclosure do not limit the division method of the optical fiber groups. In the above embodiment, the optical fiber groups are divided in such a way that the coupled optical fibers of the same optical fiber group are adjacent in sequence, while there is a gap between different optical fiber groups. It should be understood that the definition of the optical fiber group in the above embodiment is only a preferred division method, not the only division method. In some possible implementations, the coupled optical fibers in the optical fiber close-packed structure are adjacent in sequence, that is, the adjacent coupled optical fibers in the optical fiber close-packed structure abut against each other, and the coupled optical fibers can be grouped according to artificially set rules based on the detection requirements of the laser radar.

[0062] In an optical fiber group with multiple layers of coupled optical fibers arranged and stacked, as the number of layers of coupled optical fibers increases, the space occupied also increases. Although the optical fiber group containing multiple layers of coupled optical fibers increases the luminous angle density, it will increase the design difficulty when combined with optical fiber groups of other structures. For example, if three optical fiber groups are included in a close-packed optical fiber structure, and the three optical fiber groups respectively include one layer of coupled optical fiber, two layers of coupled optical fiber, and three layers of coupled optical fiber, the optical fiber group containing three layers of coupled optical fiber requires the largest height, followed by the optical fiber group containing two layers of coupled optical fiber. At this time, in order to realize the above combination scheme, in addition to providing a V-groove, the substrate also needs to be provided with an additional stepped structure to accommodate the simultaneous placement of the three optical fiber groups. Obviously, in order to achieve the above design, the manufacturing difficulty of the close-packed optical fiber structure increases, and the close-packed optical fiber structure also has the problem of structural unevenness, which can easily lead to damage and deformation.

[0063] In order to solve the above problems, in one embodiment of the present disclosure, please refer to Figure 1 The optical fiber group is a first optical fiber group or a second optical fiber group; the first optical fiber group includes at least one coupled optical fiber, the coupled optical fibers of the first optical fiber group are arranged in a single layer in parallel, one side wall of the accommodating space is provided with a V-groove, and the other side wall is provided with a plane, the V-groove of one side wall and the plane of the other side wall form a first groove group, and the first groove group is used to place the first optical fiber group; the second optical fiber group includes at least three coupled optical fibers, the coupled optical fibers of the second optical fiber group are arranged in a double layer in an staggered manner, the two side walls of the accommodating space are respectively provided with parallel V-grooves, and the V-grooves on the two side walls are staggered and opposite, the V-grooves on the two side walls form a second groove group, and the second groove group is used to place the second optical fiber group.

[0064] Based on the above configuration, the fiber group is limited to include only one or two layers of coupling fibers, the second fiber group is a two-layer coupling fiber arrangement structure, and the first fiber group is a one-layer coupling fiber arrangement structure, wherein the first fiber group may only include one coupling fiber. The purpose of this solution is to reduce the manufacturing difficulty of the fiber close-packed structure and at the same time improve the strength of the light close-packed structure. Please refer to Figure 1As can be seen from the figure, the height of the first groove group is similar to that of the second groove group. Furthermore, when manufacturing a densely packed optical fiber structure comprising the first and second optical fiber groups, only the substrate needs to be grooved to obtain the first and second groove groups. This eliminates the need for additional steps and reduces manufacturing costs. In this embodiment, when the optical fiber group includes three or more coupled optical fibers, the optical fiber group can be configured as either the first or second optical fiber group. When including the same number of coupled optical fibers, the first optical fiber group can provide a larger detection angle, thereby providing a larger detection range, but with a larger vertical angular resolution. This means that the detection range is large but the detection accuracy is low. The second optical fiber group, on the other hand, can provide a smaller vertical angular resolution. Accordingly, its detection angle is small, and its detection range is reduced compared to the first optical fiber group, but the detection accuracy is significantly improved. It should be understood that the size of the detection angle is determined by the lateral length of the optical fiber group. That is, under the condition of the same lateral length, the detection angle of the second optical fiber group is the same as that of the first optical fiber group, but the vertical angular resolution of the second optical fiber group is smaller than that of the first optical fiber group, and the luminous angle density of the second optical fiber group is greater than the luminous angle density of the first optical fiber group. That is, under the condition of the same lateral length, the second optical fiber group can achieve more precise detection.

[0065] In one embodiment of the present disclosure, please refer to Figure 1 The groove angle of the V-groove in the second groove group is 60°. At this time, the two layers of coupling optical fibers in the second optical fiber group are staggered and tangent to each other, and the three adjacent coupling optical fibers are tangent to each other, that is, the adjacent coupling optical fibers are arranged in abutment with each other. Since the groove angle of the V-groove is 60°, the groove cross-section of the V-groove is an equilateral triangle, and the V-grooves on the two side walls are staggered and opposite, that is, the bottom of the V-groove on one side of the wall is aligned with the top of the V-groove on the other side of the wall. Correspondingly, the axes of the three adjacent coupling optical fibers form the three edges of a regular triangular prism, and the three coupling optical fibers are tangent to each other, as shown in FIG. Figure 1 As shown, the minimum lateral spacing between adjacent coupled fibers is one core radius. Based on this solution, the lateral spacing between the coupled fibers in the second fiber group is halved compared to that in the first fiber group. Consequently, the vertical angular resolution of the second fiber group is half that of the first fiber group, and the luminous angle density of the second fiber group is twice that of the first fiber group. This results in a more concentrated laser beam and greater lidar detection accuracy.

[0066] Based on the above-mentioned multiple embodiments, it can be known that as the optical fiber group is limited to the first optical fiber group or the second optical fiber group, the overall height of the optical fiber group is limited, and the distance between the corresponding substrates is reduced. In order to maintain the luminous angle density and the detection range, the optical fiber group needs to add more coupling optical fibers in the horizontal direction, which will lead to an increase in the lateral length of the densely packed light structure, and in turn increase the volume of the densely packed optical fiber structure, thereby affecting the structure of the laser radar.

[0067] To address the aforementioned technical issues, in one embodiment of the present disclosure, multiple close-packed optical fiber structures can be stacked and combined. This stacking arrangement offers the advantage of reducing the lateral length of the optical fiber pack while maintaining the total number of emission bundles (i.e., the total number of coupled optical fibers included in the close-packed optical fiber structure). Furthermore, as the close-packed optical fiber structures are stacked, the resulting close-packed optical fiber structure can include a greater number of optical fiber groups. The staggered alignment of optical fiber groups in the same coupled optical fiber arrangement can increase the luminous angle density.

[0068] In order to further simplify the volume of the optical fiber close-packed structure, in one embodiment of the present disclosure, the optical fiber close-packed structure includes at least three substrates, which are stacked up and down, and a accommodating space is formed between every two adjacent substrates. At least one optical fiber group is arranged in each accommodating space.

[0069] In a specific embodiment, please refer to Figure 2 , Figure 2 The figure shows a fiber optic close-packed structure comprising three substrates. The fiber optic close-packed structure can be improved based on the fiber optic close-packed structure of the double substrate. A V-groove is also provided on the bottom of the lower substrate of the fiber optic close-packed structure of the double substrate, and an additional substrate is provided opposite to the lower substrate. A corresponding V-groove is provided on the additional substrate. In addition, it can be understood that the fiber optic close-packed structure can also be regarded as two fiber optic close-packed structures of the double substrate being stacked up and down, wherein the lower substrate of the upper fiber optic close-packed structure and the upper substrate of the lower fiber optic close-packed structure are integrally formed and provided, so as to obtain Figure 2 Based on the above configuration, compared to the stacked fiber-optic close-packed structure of dual substrates, the integrated molding solution can reduce the overall height of the fiber-optic close-packed structure, helping to reduce the volume. Furthermore, the integrated molding solution does not require additional stacking steps. During optical path debugging, only a few receiving or transmitting lines are needed to determine the relative position of the entire transceiver module, greatly reducing the manufacturing cost and assembly difficulty of the LiDAR.

[0070] In the embodiments of the present disclosure, the arrangement of the optical fiber groups in the optical fiber close-packed structure is not limited. Specifically, the hierarchical arrangement of the optical fiber groups is not limited. For example, when the optical fiber close-packed structure includes more than three substrates, that is, the optical fiber close-packed structure includes more than two layers of optical fiber groups, the optical fiber groups in different layers can be aligned or staggered. The intra-layer arrangement of the optical fiber groups is also not limited. For example, the optical fiber groups in the same layer can be symmetrically distributed or cyclically distributed, and the spacing between adjacent optical fiber groups can be fixed or variable.

[0071] In a specific embodiment, please refer to Figure 4The densely packed fiber structure shown in the figure includes two layers of fiber optic groups arranged in a staggered pattern, with the fiber optic groups within each accommodation space arranged at equal intervals. This configuration allows for evenly distributed fiber optic groups within the densely packed fiber structure, facilitating the installation of the LiDAR receiver module and ensuring a one-to-one correspondence between the module's photodetectors and the fiber optic groups, reducing the difficulty of LiDAR debugging. Furthermore, the evenly distributed fiber optic groups provide a high density of light-emitting angles and precise light-emitting angles, improving LiDAR detection accuracy.

[0072] In the embodiment of the present disclosure, when the optical fiber close-packed structure includes more than three substrates, the optical fiber close-packed structure includes more than two layers of optical fiber groups. To ensure the continuity of the luminous angle, this can be achieved by controlling the lateral distances of different optical fiber groups. Specifically, the lateral distances of adjacent coupled optical fibers within an optical fiber group are kept consistent, and the minimum lateral distance of adjacent optical fiber groups is equal to the lateral distance of adjacent coupled optical fibers within the optical fiber group. For example, please refer to Figure 4 The figure includes four fiber groups, among which the luminous angles of the two upper fiber groups (ad, eg) are both 0.5°. The lateral distance between adjacent coupled fibers in the same fiber group is one fiber radius. If the luminous angle of the coupled fiber ag is to be continuous and unchanged, the lateral distance between the coupled fibers d and e is set to one fiber radius. The lateral distance between the coupled fibers d and e is the minimum lateral distance between the two fiber groups.

[0073] In some other embodiments of the present disclosure, a radar transceiver device is also provided. Figure 3 The radar transceiver includes a transmitting module and a receiving module. The transmitting module is used to transmit a laser beam, and the receiving module is used to receive the echo signal after the laser beam irradiates the target object. Figure 3 As shown, the transmitting module includes a driving board 1 and a fiber optic close-packed structure 3 according to any one of the above embodiments. The fiber optic close-packed structure 3 is composed of a substrate with a V-groove provided on the substrate. One end of the coupling fiber 2 is fixedly placed in the V-groove, and the other end of the coupling fiber 2 is connected to the driving board 1; the receiving module includes a receiving circuit board 4, and a photodetector 41 is provided on the receiving circuit board 4.

[0074] In the disclosed embodiment, driver board 1 is a laser emitting circuit board, which includes a light source and a driver circuit. The specific type of light source is not limited; it should be understood that any light source that can be used for lidar can be applied to the solution of the disclosed embodiment. In other words, the light source can be a laser diode, a solid-state laser, or the like.

[0075] In one possible implementation, see Figure 6The driving board 1 may include multiple laser emitters 5, a fast-axis collimating fiber 6, and multiple coupling fibers 2. The laser emitters 5 and the coupling fibers 2 are respectively arranged on both sides of the fast-axis collimating fiber 6. The emission light beam of the laser emitter 5 is adjusted by the fast-axis collimating fiber 6 and then received by the coupling fibers 2. The number of coupling fibers 2 is consistent with the number of laser emitters 5. The multiple coupling fibers 2 are placed in parallel at one end away from the fiber close-packed structure 3. The fast-axis collimating fiber 6 is placed at one end of the coupling fibers 2 away from the fiber close-packed structure 3, and the fast-axis collimating fiber 6 is perpendicular to the multiple coupling fibers 2. In the above scheme, the function of the fast-axis collimating fiber 6 is to compress the divergence angle of the laser beam and adjust the laser beam to be nearly parallel light. It should be understood that the fast-axis collimating fiber 6 can be replaced with other optical fibers with the same function.

[0076] In the embodiment of the present disclosure, the receiving module should be set corresponding to the transmitting module, and the photodetector 41 in the receiving module should be flexibly selected and configured according to the optical fiber close-packed structure 3. Specifically, the receiving module may include multiple photodetectors 41, and the photodetectors 41 correspond one-to-one to the coupling optical fibers 2 in the optical fiber close-packed structure 3; or, each photodetector 41 corresponds to multiple coupling optical fibers 2, thereby reducing the cost of the receiving module of the laser radar and further realizing the miniaturization of the laser radar. In addition, the embodiment of the present disclosure does not limit the type of photodetector 41. The photodetector 41 can be an avalanche photodiode, a silicon photodiode, or a single-photon avalanche diode, etc., and a receiving module can include multiple different types of photodetectors 41.

[0077] In one embodiment of the present disclosure, the receiving module includes a plurality of photodetectors 41. The number of photodetectors 41 is consistent with the number of optical fiber groups in the optical fiber close-packed structure 3, and the photodetectors 41 correspond to the optical fiber groups one by one. In the same transceiver optical system, the focal length of the light beam is the same, so the optical path is reversible. The correspondence between the photodetectors 41 and the optical fiber groups can be established by obtaining the photosensitive range of the photodetector 41 and then placing the optical fiber group that matches it within the photosensitive range. Please refer to Figure 2, the circles in the figure represent the sensitive range of each photodetector 41 respectively. It can be seen from the figure that the photosensitive surface area of ​​each photodetector 41 covers the area of ​​the corresponding optical fiber group. In combination with the above-mentioned multiple embodiments, it can be seen that integrating adjacent coupling optical fibers 2 into an optical fiber group can not only enhance the detection performance of the laser radar, but also reduce the cost of the laser radar. In this embodiment, the photodetectors 41 are arranged in a one-to-one correspondence with the optical fiber group. One photodetector 41 can receive multiple light rays in one optical fiber group, which can reduce the number of photodetectors 41, thereby simplifying the structure of the laser radar and reducing the manufacturing cost of the laser radar. In this embodiment, the photosensitive surface area of ​​the photodetector 41 covers the area of ​​the optical fiber group, that is, the beam emitted by the coupled optical fiber 2 of the optical fiber group is within the photosensitive range of the photodetector 41, which can ensure that the energy of the optical fiber group can be received by the photodetector 41, thereby improving the accuracy of the laser radar.

[0078] In the above embodiment, the scheme of one-to-one correspondence between the photoelectric detector 41 and the optical fiber group can also reduce the difficulty of debugging the laser radar. In a specific embodiment, please refer to Figure 3 and Figure 4 The densely packed optical fiber structure 3 includes two layers of optical fiber groups, which are staggered and evenly spaced. Correspondingly, the receiving module includes two layers of photodetectors 41, which are arranged in the same manner as the optical fiber groups, and correspond one-to-one with each optical fiber group. When debugging the radar transceiver, it is necessary to ensure that the photodetectors 41 receive the echo signals of all the bundles emitted by the corresponding optical fiber groups. Since the arrangement positions of the optical fiber groups are fixed, the arrangement positions of the photodetectors 41 are also fixed, forming a single optical path between the corresponding optical fiber groups and the photodetectors 41. Once two optical paths have been debugged, the remaining optical fiber groups and photodetectors 41 are simultaneously matched. In other words, during the debugging process, at least only two optical paths can be debugged to complete the debugging of the radar transceiver. To further improve the accuracy of debugging, two optical paths that are as far apart as possible should be selected for debugging. For example, one optical path at one end of the first layer and one at the opposite end of the second layer should be selected for debugging.

[0079] In the above embodiment, the purpose of the photosensitive surface area of ​​the photodetector 41 covering the area of ​​the optical fiber group is to ensure that the energy of the optical fiber group can be received by the photodetector 41. When the laser radar is actually manufactured and used, there are factors such as debugging errors, manufacturing errors, and external damage. These factors can easily cause the optical path to deviate, and thus the photodetector 41 cannot receive the entire line bundle of the corresponding optical fiber group. Therefore, the coupling optical fiber 2 of the optical fiber group should be as close as possible to the center of the detection surface of the photodetector 41, and there should be a gap between the coupling optical fiber 2 of the optical fiber group and the edge of the detection surface of the photodetector 41.

[0080] In a specific embodiment, the core diameter of the coupling optical fiber 2 used in the transmitting module is 125um, and the diameter of the photosensitive surface of the photodetector 41 used in the receiving module is 500um. In this case, the optical fiber group includes at most four stacked and fixed coupling optical fibers 2, and when the number of coupling optical fibers 2 in the optical fiber group reaches three, the optical fiber group can only be selected as the second optical fiber group. Please refer to Figure 2 The optical fiber close-packed structure 3 under this scheme includes four optical fiber groups with different structures, and the corresponding numbers of coupled optical fibers 2 are one, two, three and four respectively.

[0081] In the above embodiment, since the photodetector 41 corresponds one-to-one to the optical fiber group, the photodetector 41 needs to receive the bundles of multiple coupled optical fibers 2 in the optical fiber group. If multiple coupled optical fibers 2 in the same optical fiber group emit light at the same time, then the photodetector 41 also needs to receive multiple echo signals at the same time. Since the optical fiber group has a large light-emitting angle density and a small vertical angular resolution, the echo signals received by the photodetector 41 are also concentrated, which may increase the difficulty of processing point cloud data and create the risk of garbled imaging.

[0082] In order to solve the above-mentioned technical problems, in one embodiment of the present disclosure, the coupling optical fibers 2 belonging to the same optical fiber group emit light at different timings. Based on this solution, the coupling optical fibers 2 of the same optical fiber group cannot emit light at the same time, which can avoid misjudgment when the photodetector 41 receives signals from the same optical fiber group, thereby ensuring the detection accuracy of the laser radar. It should be understood that the coupling optical fibers 2 of the same optical fiber group should also avoid emitting light at adjacent timings. Otherwise, within a time interval, the photodetector 41 corresponding to the optical fiber group needs to continuously receive the echo signal, which will cause identification interference and easily lead to the signal of one coupling optical fiber 2 being misjudged as the signal of another coupling optical fiber 2, thereby causing inaccurate detection. In addition, the same optical fiber group emitting light beams simultaneously or in sequence can also easily lead to competitive interference of signal components. Therefore, multiple coupling optical fibers 2 of the same optical fiber group should emit light beams in sequence at intervals to ensure the detection accuracy of the laser radar.

[0083] In a specific embodiment, the optical fiber groups corresponding to the photodetectors 41 that are farther away can be selected to emit light simultaneously or in adjacent time sequence. Figure 4 and Figure 5 The figure contains four optical fiber groups. The coupling optical fibers 2 are a to l from top to bottom. A, B, C, and D are a fiber group, E, F, and G are a fiber group, H, I, and J are a fiber group, and K and L are a fiber group. The corresponding light emission timing is agbhcidjekfl.

[0084] Some other embodiments of the present disclosure further provide a laser radar system, which includes a radar transceiver device as described in any one of the above embodiments.

[0085] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A densely packed optical fiber structure, used in laser radar, characterized by: The optical fiber close-packed structure includes two substrates stacked up and down, and the opposite surfaces of the two substrates form an accommodating space; A V-groove is formed on at least one side wall of the accommodating space, wherein the V-groove is used to place coupling optical fibers, adjacent coupling optical fibers form an optical fiber group, and a lateral spacing between adjacent coupling optical fibers in an optical fiber group is less than or equal to one fiber core diameter; At least two optical fiber groups are arranged in the accommodating space, and there is a distance between different optical fiber groups. Each optical fiber group forms a detection range.

2. The optical fiber close-packed structure according to claim 1, characterized in that: The optical fiber group is the first optical fiber group or the second optical fiber group; The first optical fiber group includes at least one coupling optical fiber, and the coupling optical fibers of the first optical fiber group are arranged in a single layer in parallel. One side wall of the accommodating space is provided with a V-groove, and the other side wall is provided with a flat surface. The V-groove on one side wall and the flat surface on the other side wall form a first groove group, and the first groove group is used to accommodate the first optical fiber group; The second optical fiber group includes at least three coupled optical fibers, and the coupled optical fibers of the second optical fiber group are arranged in a double-layer staggered manner. The two side walls of the accommodating space are respectively provided with parallel V-grooves, and the V-grooves on the two side walls are staggered and opposite to each other. The V-grooves on the two side walls form a second groove group, and the second groove group is used to place the second optical fiber group.

3. The optical fiber close-packed structure according to claim 2, characterized in that: The groove angle of the V-grooves in the second groove group is 60°. The two layers of coupling optical fibers in the second optical fiber group are staggered and tangent to each other, and three adjacent coupling optical fibers are tangent to each other in pairs.

4. The optical fiber close-packed structure according to claim 2 or 3, characterized in that: The optical fiber close-packed structure includes at least three substrates, which are stacked up and down. An accommodating space is formed between every two adjacent substrates, and at least one optical fiber group is arranged in each accommodating space.

5. The optical fiber close-packed structure according to claim 4, characterized in that: The lateral distances between adjacent coupled optical fibers in the optical fiber group are consistent, and the minimum lateral distance between adjacent optical fiber groups is equal to the lateral distance between adjacent coupled optical fibers in the optical fiber group.

6. A radar transceiver device, comprising a transmitting module and a receiving module, characterized in that: The transmitting module is used to transmit a laser beam, and the transmitting module includes a driving board and a close-packed optical fiber structure according to any one of claims 1 to 5, the driving board includes a light source and a driving circuit, and the driving board is connected to the close-packed optical fiber structure via a coupling optical fiber; The receiving module is used to receive the echo signal, and the receiving module includes a photoelectric detector.

7. The radar transceiver according to claim 6, characterized in that: The receiving module includes a plurality of photodetectors, the number of which is consistent with the number of optical fiber groups in the optical fiber close-packed structure, the photodetectors correspond one-to-one to the optical fiber groups, and the photosensitive surface area of ​​each photodetector covers the area of ​​the corresponding optical fiber group.

8. The radar transceiver according to claim 6, characterized in that: The coupling optical fibers belonging to the same optical fiber group emit light at different timings.

9. The radar transceiver according to claim 6, characterized in that: The photodetector includes an avalanche photodiode, a silicon photodiode or a single photon avalanche diode.

10. A laser radar system, characterized in that: A radar transceiver device comprising any one of claims 6 to 9.

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