The present application claims the benefit of priority to Chinese Patent Application Nos. 202211102152.3 and 202211105845.8, both filed on Sep. 9, 2022, which are hereby incorporated by reference in their entireties.
The present application pertains to the technical field of autonomous driving, and in particular, relates to a transceiving module and a LiDAR.
A LiDAR is a radar system that emits a laser beam to obtain characteristics of targets such as position and speed. The working principle of the LiDAR is to first emit detection laser beams to the target, then compare received signals reflected from the target with emitted signals, and properly process the signals to obtain relevant information of the target, for example, parameters of the target such as distance, azimuth, height, speed, posture, and even shape.
However, an existing LiDAR coaxial transceiving system using integrated optical technologies requires a free-space optical circulator, which causes low production efficiency, low integration, and high overall costs for the LiDAR; and resolution of such LiDAR depends on a scanning speed, and therefore, the resolution can be improved to a limited extent.
The present application aims to provide a transceiving module and a LiDAR, to resolve technical problems of high costs, and insufficient ranging capability and resolution of the LiDAR in the related art.
The present application is implemented in the following manner: According to a first aspect, a transceiving module is provided, including a substrate and multiple transceiving assemblies, where the multiple transceiving assemblies are arranged on the substrate in sequence along a first direction, each transceiving assembly includes an emission waveguide and a receiving waveguide, the emission waveguide is configured to transmit and emit a detection beam, and the receiving waveguide is configured to receive and transmit an echo beam.
In an embodiment, the transceiving module further includes a reflection structure formed on a first side of the transceiving assembly, the first side is a side on which the transceiving assembly emits the detection beam and receives the echo beam, the reflection structure includes a first reflection region corresponding to the emission waveguide, and a second reflection region corresponding to the receiving waveguide, the first reflection region is configured to reflect the detection beam emitted by the emission waveguide, to emit the detection beam outwards, and the second reflection region is configured to receive and reflect the echo beam, so that the echo beam enters the receiving waveguide.
In an embodiment, the reflection structure includes multiple reflection slopes corresponding to the multiple transceiving assemblies to form a quantity correspondence, each reflection slope includes a first reflection region and a second reflection region, the detection beam emitted by the emission waveguide is deflected on the first reflection region of the reflection slope, and the echo beam is deflected on the second reflection region of the reflection slope and then enters the receiving waveguide.
In an embodiment, the reflection structure and the transceiving assembly are disposed at intervals.
In an embodiment, the multiple reflection slopes are staggered along a second direction, and the second direction is perpendicular to the first direction.
In an embodiment, the multiple reflection slopes are sequentially connected to form a combined surface.
In an embodiment, the transceiving assembly and the reflection structure are disposed on a first surface of the substrate.
In an embodiment, an accommodating cavity is disposed on the first surface, and the reflection structure is disposed in the accommodating cavity.
In an embodiment, the reflection structure is fixed in the accommodating cavity.
In an embodiment, the transceiving module further includes an upper coating covering the first surface of the substrate and the transceiving assembly, and the reflection structure is disposed on a second surface of the upper coating.
In an embodiment, the transceiving assembly includes one emission waveguide and at least one receiving waveguide arranged along the first direction, and the receiving waveguide is on the same side or two sides of the emission waveguide.
In an embodiment, in the same transceiving assembly, a light outgoing surface of the emission waveguide and a light incident surface of the receiving waveguide are on the same plane; or the light incident surface of the receiving waveguide is staggered behind the light outgoing surface of the emission waveguide in the second direction.
In an embodiment, each transceiving assembly includes an emission waveguide and a receiving waveguide disposed at intervals along the first direction; a first reflection surface is disposed on a light outgoing side of the emission waveguide, and the first reflection surface is configured to reflect a detection beam transmitted in the emission waveguide, to emit the detection beam outwards; and a second reflection surface is disposed on the light incident side of the receiving waveguide, and the second reflection surface is configured to receive and reflect the echo beam, so that the echo beam enters the receiving waveguide.
In an embodiment, the first reflection surface is formed on a light outgoing terminal of the emission waveguide, and the second reflection surface is formed on a light incident terminal of the receiving waveguide.
In an embodiment, the transceiving assembly includes one emission waveguide and one receiving waveguide arranged along the first direction, and a distance between the emission waveguide and the receiving waveguide is less than 2 μm.
In an embodiment, the first reflection surface of the emission waveguide and the second reflection surface of the receiving waveguide that belong to the same transceiving assembly are aligned in the first direction.
In an embodiment, a flared structure is formed on an input terminal of the receiving waveguide.
In an embodiment, the substrate is on the light outgoing side of the detection beam, an included angle between the first reflection surface and the first surface is 30° to 60°, and an included angle between the second reflection surface and the first surface is also 30° to 60°; or the substrate is on a side facing away from the light outgoing side of the detection beam, an included angle between the first reflection surface and the first surface is 120° to 150°, and an included angle between the second reflection surface and the first surface is also 120° to 150°.
In an embodiment, both the first reflection surface and the second reflection surface are coated with a high-reflection film; and the quantity of transceiving assemblies is greater than or equal to 2, and the multiple transceiving assemblies are arranged in sequence along the first direction.
According to a second aspect, a LiDAR is provided, including an emission module, a receiving module and a scanning module, and further including the transceiving module provided in the foregoing embodiments, where the emission module emits a detection beam; the detection beam enters the transceiving module and is directed by the transceiving module towards the scanning module, and the scanning module deflects the detection beam and then emits the detection beam outwards for detection; and the scanning module is also configured to receive an echo beam, deflect the echo beam and then emit the echo beam to the transceiving module, and the echo beam enters the transceiving module and enters the receiving module through the transceiving module.
In an embodiment, the emission module and the receiving module are located on the same transceiving chip, and the transceiving chip is coupled to the transceiving module.
Compared with the related art, a technical effect of the present application is: In the transceiving module and the LiDAR provided in the embodiments of the present application, the transceiving module includes the substrate and the multiple transceiving assemblies, where the multiple transceiving assemblies are arranged on the substrate in sequence along the first direction, each transceiving assembly includes the emission waveguide and the receiving waveguide, the emission waveguide is configured to transmit and emit the detection beam, and the receiving waveguide is configured to receive and transmit the echo beam. According to the first aspect, the transceiving module provided in the embodiments of the present application is provided with the multiple transceiving assemblies in the first direction, one transceiving assembly forms a detection channel, and the transceiving module is disposed, so that a first direction of the transceiving module and a direction Y of the scanning module are parallel, to form multiple detection channels in the direction Y, which can effectively improve resolution of the LiDAR in the direction Y. A waveguide of each transceiving assembly directly transmits and receives a beam. The transceiving module is integrated on a planar optical waveguide chip to implement integration of receiving and emission without using a spatial optical circulator, thereby improving integration of the LiDAR. According to the second aspect, in the transceiving module provided in the embodiments of the present application, the emission waveguide and the receiving waveguide are disposed on the surface of the substrate, so that the first direction of the transceiving module is parallel to the direction Y, without a need to stack multiple transceiving assemblies in a thickness direction of the planar optical waveguide chip to improve resolution in the direction Y, thereby optimizing a chip design and simplifying processing. According to the third aspect, an optical path along a direction parallel to the surface of the substrate can be deflected via the reflection structure, and the multiple reflection slopes are staggered in the second direction, which can not only increase the quantity of detection channels arranged in the second direction, but also increase resolution of the LiDAR in a direction X and a vertical direction Y.
To explain the technical solution in embodiments in the present application more clearly, the following briefly introduces the accompanying drawings required for description in the embodiments of the present application or the related art. Obviously, the accompanying drawings in the following description are only some embodiments in the present application. A person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.
The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, and the same or similar reference signs indicate the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and intended to explain the present application, but cannot be construed as a limitation on the present application.
In the description of the present application, it should be understood that azimuth or position relationships indicated by terms such as “length,” “width,” “above,” “under,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer” are based on the azimuth or position relationships shown in the accompanying drawings, are merely intended to describe the present application and simplify the descriptions, but are not intended to indicate or imply that the specified device or element shall have specific azimuth or be formed and operated in specific azimuth, and therefore cannot be understood as a limitation on the present application.
In addition, the terms such as “first” and “second” are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature with a determiner such as “first” or “second” may expressly or implicitly include one or more features. In the description of the present application, “a plurality of” means two or more, unless otherwise specifically defined.
In the present application, unless otherwise clearly specified and limited, terms such as “mounting,” “connection,” “link,” and “fixing” should be understood in a general sense. For example, these terms may be a fixed connection, a detachable connection, or an integrated connection; or may be a mechanical connection or an electrical connection; or may be a direct connection, an indirect connection via an intermediate medium, or an internal link of two elements or an interaction of two elements. A person of ordinary skill in the art may understand specific meanings of the foregoing terms in the present application according to a specific situation.
To make the objectives, technical solutions, and advantages of the present application more comprehensible, the following further describes the present application in detail with reference to accompanying drawings and embodiments.
As shown in
The ranging principle applicable to the foregoing LiDAR can be Time of Flight (ToF) or Frequency Modulated Continuous Wave (FMCW). The scanning module 400 deflects a beam in direction X (horizontal direction) and direction Y (vertical direction), so that the LiDAR scans in the horizontal direction and the vertical direction.
Referring to
As shown in
During detection, as shown in
According to the first aspect, the transceiving module 100 provided in the embodiments of the present application is provided with the multiple transceiving assemblies 120 in the first direction, one transceiving assembly 120 forms one detection channel, and a first direction is set to be parallel to a direction Y of the scanning module 400, to form multiple detection channels in the direction Y, which can effectively improve resolution of the LiDAR in the direction Y. A waveguide of each transceiving assembly 120 directly transmits and receives a beam. The transceiving module 100 is integrated on a planar optical waveguide chip to implement integration of receiving and emission without using a spatial optical circulator, thereby improving integration of the LiDAR. According to the second aspect, in the transceiving module 100 provided in the embodiments of the present application, the emission waveguide 121 and the receiving waveguide 122 can be disposed on the surface of the substrate 110, so that the first direction of the transceiving module 100 is set to be parallel to the direction Y, to form the multiple detection channels in the direction Y, without a need to stack multiple transceiving assemblies 120 in a thickness direction of the planar optical waveguide chip, thereby optimizing a chip design and simplifying processing.
As shown in
In this embodiment, the emission waveguide 121, the receiving waveguide 122 and the reflection structure 130 are disposed in the transceiving module 100, the emission waveguide 121 corresponds to the first reflection region, and the receiving waveguide 122 corresponds to the second reflection region. Optical paths of the detection beam transmitted in the emission waveguide 121 and the echo beam transmitted in the receiving waveguide 122 are deflected after reflection of the reflection structure 130, and therefore, a transmission direction of the detection beam originally transmitted in a direction parallel to the surface of the substrate 110 is changed to a direction perpendicular to the surface of the substrate 110, or a direction forming another angle with the surface of the substrate 110; in addition, an echo beam in the direction perpendicular to the surface of the substrate 110 or in a direction forming another angle with the surface of the substrate 110 can enter the receiving waveguide 122.
Based on the transceiving module 100 provided in this embodiment, multiple optical paths that are used for emission and reception and that pass through the transceiving module 100 can be staggered on both a plane parallel to the surface of the substrate 110 and a plane perpendicular to the surface of the substrate 110 or a plane forming a specific angle with the surface of the substrate 110, which effectively resolves a problem that optical paths cannot be staggered in two directions in a planar waveguide chip using a one-dimensional waveguide array. In the LiDAR using the foregoing transceiving module 100, optical paths of the multiple transceiving modules 100 are separately staggered in two directions, and the to-be-detected region is scanned after the optical paths pass through the scanning module, which can increase resolution in the direction X and the direction Y simultaneously.
In an embodiment, reflection structures are disposed on terminal surfaces of the emission waveguide and the receiving waveguide. A surface of a terminal of the emission waveguide that emits the detection beam is processed into an inclined plane, a reflection coating, a reflection film, or the like is disposed on the inclined plane to form a reflection surface, and the first reflection region is on a reflection surface of the emission waveguide. Likewise, for a second reflection region, a surface of a terminal of the receiving waveguide that receives the echo beam is processed into an inclined plane, a reflection coating, a reflection film, or the like is disposed on the inclined plane to form a reflection surface, and the second reflection region is on a reflection surface of the receiving waveguide. Included angles between the substrate and the inclined planes of the terminal surface of the emission waveguide and the terminal surface of the receiving waveguide satisfy a preset angle, for example, 30° to 60°. An outgoing direction of the detection beam reflected by the inclined plane of the emission waveguide forms an included angle 1 with the surface of the substrate 110. In addition, an echo beam in an incident direction forming an included angle 2 (which may be approximately equal to the included angle 1) with the surface of the substrate 110 enters the receiving waveguide after being reflected by the inclined plane of the receiving waveguide. The included angle 1 mentioned herein can be 90°, an acute angle relative to the surface of the substrate 110, or an obtuse angle relative to the surface of the substrate 110, which can be specifically designed based on a light emission requirement. The angle 2 is similar to the angle 1. Details are not described herein again.
In another embodiment, as shown in
The first reflection region and the second reflection region can be designed based on an optical setting need. For example, for the detection beam and the echo beam, because displacement of the scanning module during flight of photons causes a walkoff effect of a receiving angle, optical paths of the detection beam and the echo beam may not completely overlap with each other. The first reflection region and the second reflection region may not be on the same reflection slope, and included angles between the first reflection region, the second reflection region and the surface of the substrate are adjusted, or distances between the first reflection region, the second reflection region and the waveguide are adjusted, so that the optical path is aligned with the corresponding reflection region, thereby improving emission efficiency and reception efficiency. Therefore, the reflection slope in which the first reflection region is located and the reflection slope in which the second reflection region is located may also be at different tilt angles. To facilitate processing and simplify a design, the first reflection region and the second reflection region are arranged on the same reflection slope. As shown in
In some embodiments, the reflection slope 132 can be an independent part, and is disposed on the substrate 110. For example, the substrate 110 is provided with a slope structure forming the reflection slope 132, and a reflection coating, a reflection film, or the like is disposed on the slope structure to form the reflection slope 132, or a reflector is fixed on the slope structure, and the reflector is the reflection slope 132, which can effectively reduce processing difficulty of the reflection structure, so that the reflection structure and the transceiving assembly can be maintained independently without affecting each other.
In some embodiments, the reflection slope 132 can be directly disposed on the substrate 110. For example, the surface of the substrate 110 is directly provided with a slope structure forming the reflection slope 132, and a reflection coating, a reflection film, or the like is disposed on the slope structure to form the reflection slope 132, or a reflector is fixed on the slope structure, and the reflector is the reflection slope 132, which simplifies a manufacturing step of the reflection structure and production.
In an embodiment, the multiple reflection slopes are staggered along a second direction B, and the second direction is perpendicular to the first direction, which can increase the quantity of channels in the second direction B. When the transceiving assembly is disposed vertically and the first direction A of the transceiving assembly is parallel to the direction Y, the second direction B is parallel to the direction X, after deflection of the corresponding reflection slope, optical paths for channels are staggered in the direction X, and therefore, the quantity of detection channels of the LiDAR in the direction X can be effectively increased, that is, resolution of the corresponding LiDAR in the direction X is increased, which improves detection accuracy of the LiDAR and can also reduce an adverse effect of the walkoff effect of the receiving angle in the direction X on detection of the LiDAR, thereby improving a ranging capability of the corresponding LiDAR.
Taking the first reflection slope at the outermost edge as a reference, a staggered distance between the second reflection slope and the reference along the second direction B is d2, and by analogy, a staggered distance between an Nth reflection slope and the reference along the second direction B is dN. The multiple reflection slopes may be sequentially staggered along the second direction B, that is, d2 to dN increase sequentially. The staggered distances between the multiple reflection slopes along the second direction B may be in an ascending order first and then a descending order (or in a descending order first and then an ascending order), or may be set randomly. Provided that d2 to dN are not all equal, the optical paths for multiple channels can be staggered in the direction X after deflection of the corresponding reflection slope, thereby improving the resolution of the LiDAR in the direction X.
The multiple reflection slopes 132 included in the reflection structure may be separate structures. For example, each transceiving assembly is correspondingly provided with an independent slope structure. The multiple reflection slopes may also be sequentially connected to form a combined surface. Corresponding positions and the set quantity of the multiple reflection slopes correspond to those of the transceiving assemblies. To facilitate processing, the multiple reflection slopes can be sequentially connected through a transition surface, and the reflection structure is an integrated structure. As shown in
Positions of multiple transceiving assemblies corresponding to multiple reflection slopes in the second direction B do not affect a position of the optical path in the direction X after being directed out of the LiDAR, and offset of the optical path for each channel in the direction X is related to the position of the reflection slope. Therefore, the positions of the multiple transceiving assemblies in the second direction B can be set randomly. In some embodiments, first terminals of the multiple transceiving assemblies are arranged on the same plane, which simplifies a production process. The first terminal of the transceiving assembly may be a central point of a light outgoing surface of the emission waveguide in the transceiving assembly. In some embodiments, as shown in
To increase an emission rate of the detection beam and a reception rate of the echo beam, based on the foregoing embodiments, the reflection slope is a total reflection surface.
In an embodiment, as shown in
In an embodiment, as shown in
In an embodiment, the reflection structure 130 is fixed in the accommodating cavity 111. As shown in
In an embodiment, as shown in
In an embodiment, as shown in
In some embodiments, to satisfy optical performance of the reflection structure 130, for example, a flatness requirement or thermal deformation of the first reflection region and the second reflection region, a material used is relatively expensive. The reflection structure 130 is arranged on a base 160, and the base 160 is a structure for adjusting the height of the reflection structure 130, so that the height of the reflection structure 130 matches the height of the transceiving assembly, and the optical path of the transceiving assembly is aligned with the reflection slope of the reflection structure 130. In this way, the costs of the entire transceiving module 100 can be reduced, and the two parts can be assembled after production to achieve optical cooperation, thereby reducing processing difficulty.
An embodiment of the present application also provides a transceiving module 100. A transceiving assembly 120 in the transceiving module 100 includes one emission waveguide 121 and at least one receiving waveguide 122 arranged along a first direction A. Generally, the transceiving assembly 120 includes one emission waveguide 121 and one receiving waveguide 122 arranged side by side along the first direction A, the emission waveguide 121 is configured to transmit the detection beam, and the receiving waveguide 122 is configured to transmit the echo beam, so that functions of the transceiving assembly 120 can be realized.
When the LiDAR provided in the foregoing embodiment is used for detection, the scanning module 400 deflects the optical path to quickly scan the field of view to detect an object in the to-be-detected region. Due to relatively long time of flight of photons in long-distance detection, the scanning module 400 has moved non-negligibly during this period of time; and a spatial orientation of the scanning module 400 when receiving the echo beam is different from a spatial orientation when the detection beam is emitted, which causes a walkoff effect of a scanning receiving angle of the LiDAR. Offset caused by the walkoff effect of the receiving angle is related to the time of flight of photons. The longer the time, the larger the offset. Therefore, the offset of an echo beam returned after being reflected from an object at a greater distance is greater. The walkoff effect of the scanning receiving angle of the LiDAR mentioned herein is manifested in both the direction X and the direction Y.
In an embodiment, as shown in
Further, at least one receiving waveguide 122 may be on the same side of the emission waveguide 121. As shown in
The at least one receiving waveguide 122 may be on two sides of the emission waveguide 121. As shown in
Further, a distance d between a receiving waveguide closest to the emission waveguide and the emission waveguide is less than or equal to 2 μm. Because the emission optical path and the receiving optical path of the transceiving assembly are approximately coaxial, the scanning module or another optical system in front of the transceiving assembly also follows the approximately coaxial design of the emission optical path and the receiving optical path, and therefore, all returned echo beams fall near the emission waveguide. To ensure the rate of receiving the echo beam by the receiving waveguide, the receiving waveguide is disposed close to the emission waveguide.
In an embodiment, as shown in
Further, in the same transceiving assembly, a light outgoing surface of the emission waveguide and a light incident surface of the receiving waveguide may be on the same plane. As shown in
In the same transceiving assembly, the light incident surface of the receiving waveguide may be staggered behind the light outgoing surface of the emission waveguide in the second direction B. As mentioned above, in the two-dimensional scanning LiDAR, the walkoff effect of the scanning receiving angle occurs in both the direction X and the direction Y. Multiple receiving waveguides in the same transceiving assembly are arranged along the first direction A, which can compensate for the offset of the echo beam in the first direction A; and through the optical design of the transceiving module and the scanning module of the LiDAR, the first direction A can be consistent with the direction Y. At this time, with the arrangement of the multiple receiving waveguides of the LiDAR, the offset of the echo beam in the direction Y can be compensated for. By analogy, the light incident surfaces of the multiple receiving waveguides are staggered backward in the second direction B, which can compensate for the offset of the echo beam in the second direction B. Similarly, light incident surfaces of multiple receiving waveguides of the LiDAR using the foregoing optical design are staggered in the second direction B, which can compensate for the offset of the echo beam in the direction X. Disposing the receiving waveguides in this way can improve the receiving efficiency of each transceiving assembly, thereby improving the receiving efficiency of the transceiving module and the LiDAR.
On the basis of the foregoing embodiments, the second terminals of the multiple transceiving assemblies 120 are located on the same plane, and the second terminal is the terminal of the transceiving assembly 120 that receives the detection beam and outputs the echo beam. With this structure, the light incident terminals of all emission waveguides 121 and the light outgoing terminals of all receiving waveguides 122 are located on the same plane, which facilitates coupling of the transceiving module 100 and the transceiving chip 500 during use.
For the transceiving module 100 disclosed in the foregoing embodiment, first, multiple transceiving assemblies are arranged on a surface of a PLC (Planar Lightwave Circuit) chip along the first direction, so that multiple optical paths emitted and received by the transceiving module are staggered along the first direction. Then a reflection structure is disposed at the first terminal of each transceiving assembly to change a direction of the optical path of the transceiving assembly from a direction parallel to the surface of the PLC chip to a direction forming a specific angle with the surface of the PLC chip, so that multiple optical paths emitted and received by the transceiving module are staggered along the second direction. The transceiving module used in the LiDAR is arranged vertically, the first direction A is parallel to the direction Y, and the second direction B is parallel to the direction X, which can improve both resolution in the direction X and resolution in the direction Y. In addition, compared with the design method in which multiple groups of emission waveguides and receiving waveguides are stacked in a thickness direction of the PLC chip to improve both the resolution in the direction X and the resolution in the direction Y, a configuration manner of the transceiving module provided in the foregoing embodiment is used, in a production process, there is no need to perform operations such as thinning and precise alignment on a wafer of the PLC chip, which can effectively reduce the production costs of the transceiving module and improve production efficiency, so that integration of the overall structure is higher, production efficiency is higher, and the costs are lower.
Referring to
The emission module 200 in this embodiment may include a laser beam source. The laser source can be a DFB laser (Distributed Feedback Laser), an EEL laser (Edge Emitting Laser), a VCSEL (Vertical Cavity Surface Emitting Laser), or a laser source combining the DFB laser and the EDFA (Erbium-doped Optical Fiber Amplifier). A coupling manner of the emission module 200, the receiving module 600 and the transceiving module 100 may be fiber coupling, grating coupling, microlens coupling, or direct coupling. The receiving module 600 may include a combination of one or more of a receiver and a processing circuit, a receiving and processing chip, and a silicon optical coherent receiving chip.
As shown in
A working principle of the LiDAR provided in this embodiment is as follows.
The emission module 200 emits detection beams, and the detection beams are coupled to enter the transceiving module 100, are transmitted and emitted by the transceiving module 100 to the scanning module 400, are deflected by the scanning module 400 and are then emitted outwards to a to-be-detected region. Then, echo beams returned after being reflected by an object in the to-be-detected region are received by the scanning module 400, and the scanning module 400 deflects the echo beams and then emits the echo beams to the transceiving module 100. The echo beams are coupled to enter the transceiving module 100. The transceiving module 100 emits the echo beams to the receiving module 600, and the receiving module 600 performs calculation according to the received echo beams to obtain a detection result.
The LiDAR provided in the embodiments of the present application uses the transceiving module 100 provided in the foregoing embodiments, so that the LiDAR has multiple detection channels in the vertical direction, which can effectively improve resolution of the LiDAR in the vertical direction, and implement integration of transceiving functions without requiring a spatial optical circulator, thereby implementing a high degree of integration.
In an embodiment, as shown in
In an embodiment, as shown in
In an embodiment, as shown in
The frequency-modulated continuous-wave LiDAR further includes a signal processing module 800 for processing an echo electric signal output by the receiving module 600. The signal processing module 800 includes a signal adjustment circuit, a signal collection circuit, a signal processing circuit, an algorithm control circuit, an external interface, and the like.
The emission module 200 can emit the detection beams by using a fiber laser, the detection beams are coupled through one or more optical fibers to enter the emission waveguides 121 of the N transceiving assemblies of the transceiving module 100, the receiving waveguides 122 of the N transceiving assemblies receive the corresponding echo beams, and then the echo beams are coupled to enter the receiving module 600. The light-splitting module 700 splits the local oscillator beam into N parts to be coupled to enter the receiving module 600. The receiving module 600 includes N receiving paths, each receiving path respectively receives one local oscillator beam and one echo beam of the receiving waveguide 122, outputs the corresponding echo electric signal after frequency beating, and sends the echo electric signal to the signal processing module 800.
An embodiment of the present application provides another transceiving module. Referring to
The first reflection surface 1211 is disposed on a light outgoing side of the emission waveguide 121, and the first reflection surface 1211 is configured to reflect a detection beam transmitted in the emission waveguide 121, to emit the detection beam outwards. The second reflection surface 1221 is disposed on the light incident side of the receiving waveguide 122, and the second reflection surface 1221 is configured to receive and reflect the echo beam, so that the echo beam enters the receiving waveguide 122.
In this embodiment, the first reflection surface 1211 can be formed at the terminal of the emission waveguide 121, or can be disposed independently. When disposed independently, the first reflection surface can be prepared on the substrate 110 and disposed independently of the emission waveguide 121, which can be flexibly selected according to a use need. Likewise, the second reflection surface 1221 can be formed at the terminal of the receiving waveguide 122, or can be disposed independently. When disposed independently, the second reflection surface can be prepared on the substrate 110 and disposed independently of the receiving waveguide 122, which can be flexibly selected according to a use need. In addition, the first reflection surface 1211 and the second reflection surface 1221 are both inclined, so that an outgoing direction of the detection beam reflected by the first reflection surface 1211 forms an included angle with the first surface 112. The included angle mentioned herein can be 90°, a specific acute angle relative to the first surface 112, or a specific obtuse angle relative to the first surface 112, which can be designed based on a light emission requirement. In addition, an incident direction of the echo beam forms an included angle with the first surface 112. The included angle mentioned herein can be 90°, a specific acute angle relative to the first surface 112, or a specific obtuse angle relative to the first surface 112, which can be designed based on a light emission requirement.
The emission waveguide 121 in this embodiment can be a single-mode waveguide, the receiving waveguide 122 can be a single-mode waveguide or a multi-mode waveguide, and a material of the waveguide can be a SiO2 material, an organic polymer material, or a silicon material. In addition, the emission waveguide 121 and the receiving waveguide 122 can use structures with equal cross sections respectively, and can also use structures switching from the single mode to the multi-mode or from the multi-mode to the single mode. During manufacture, an organic polymer can be first directly imprinted on the substrate 110, and then corresponding surfaces of the emission waveguide 121 and the receiving waveguide 122 are coated to form the first reflection surface 1211 and the second reflection surface 1221; or the emission waveguide 121 and the receiving waveguide 122 can be prepared first, and then the emission waveguide 121 and the receiving waveguide 122 can be assembled onto the substrate 110 in a precise assembly manner. In another embodiment, the emission waveguide 121 and the receiving waveguide 122 can also be manufactured via etching, machining, or the like. This is not limited herein.
In this embodiment, the substrate 110 may be on the light outgoing side of the emission waveguide 121, or on a side facing away from the light outgoing side of the emission waveguide 121. When the substrate 110 is on the light outgoing side of the emission waveguide 121, the substrate 110 needs to be made of a translucent material. At this time, the emission waveguide 121 and the receiving waveguide 122 are on an inner side of the transceiving module and are uneasy to damage. When the substrate 110 is on the side facing away from the light outgoing side of the emission waveguide 121, the beam is directly emitted out without passing through the substrate 110, and it is unnecessary to consider impact of a material of the substrate on the detection beam and the echo beam when the substrate 110 is designed, so that a large range of materials can be selected for preparing the substrate 110, which facilitates designing and processing of the substrate.
A working principle of the LiDAR provided in this embodiment of the present application is as follows.
When a target object is detected, the emission module 200 emits a detection beam, the detection beam passes through an incident terminal of the emission waveguide 121 to enter the emission waveguide 121, is transmitted by the emission waveguide 121 and then reaches the first reflection surface 1211, then is reflected by the first reflection surface 1211 to reach the collimating module 300, and is collimated by the collimating module 300, and then passes through the scanning module 400 to form the scanning beam; and the scanning beam is incident on the target object, and then the beam is reflected by the target object to form an echo beam. The echo beam passes through the scanning module 400 and the collimating module 300 in sequence to be incident on the second reflection surface 1221, and then is reflected by the second reflection surface 1221 to enter the receiving waveguide 122, then transmitted to an output terminal of the receiving waveguide 122 through the receiving waveguide 122, and then output to the receiving module 600 through the receiving waveguide 122. The receiving module 600 receives and processes the echo beam.
However, in the transceiving module 100 provided in this embodiment of the present application, the first reflection surface 1211 is disposed on the light outgoing side of the emission waveguide 121, and the second reflection surface 1221 is disposed on the light incident side of the receiving waveguide 122, so that a transmission direction of the detection beam originally parallel to the first surface 112 is changed to a direction perpendicular to the first surface 112 or a direction forming another included angle with the first surface 112, and an echo beam that is perpendicular to the first surface 112 or forms another included angle with the first surface 112 can be received by the receiving waveguide 122. In addition, the emission waveguide 121 and the receiving waveguide 122 are arranged at intervals along the first direction A. During use, azimuth of the transceiving module is designed, so that the first direction A is parallel to the direction Y, and the echo beam can still be received by the receiving waveguide 122 even if the echo beam and the detection beam are staggered by an angle≥0.05° in the direction Y. During use, multiple transceiving assemblies are arranged in the first direction A as required, and the multiple transceiving assemblies are staggered in the second direction B parallel to the direction X, which can improve the quantities of detection channels in both the direction X and the direction Y and further improve the resolution of the LiDAR in both the direction X and the direction Y.
In addition, the transceiving module 100 provided in this embodiment of the present application is used, so that the LiDAR needs no free-space optical circulator, which reduces hardware overheads and costs, simplifies the system, and reduces complexity of the optical-mechanical system, thereby reducing a volume of the entire system and improving reliability.
It can be seen that, in the first aspect, the transceiving module 100 provided in this embodiment of the present application is provided with at least one transceiving assembly in the first direction A, a waveguide of each transceiving assembly directly transmits and receives a beam. The transceiving module 100 is integrated on a planar optical waveguide chip to implement integration of receiving and emission without using a spatial optical circulator, thereby improving integration of the LiDAR. In addition, the first reflection surface 1211 and the second reflection surface 1221 are used, so that the optical path along the direction parallel to the surface of the substrate 110 is deflected and the transceiving module 100 can emit beams in two directions, which facilitates adjustment of positions of optical paths of the transceiving assembly in two directions, or adjustment of a relative positional relationship of optical paths of multiple transceiving assemblies, thereby optimizing resolution of the LiDAR in both the direction X and the direction Y. According to the second aspect, the emission waveguide 121 and the receiving waveguide 122 of each transceiving assembly are arranged at intervals, to compensate for a walkoff effect (walkoff effect) of the receiving angle in the first direction A, thereby improving receiving efficiency in the first direction A and further improving the ranging capability of the LiDAR.
During processing, one terminal of the emission waveguide 121 can be first processed into a slope, and then the slope can be coated with a total reflection waveguide film, or attached with a reflection film or the like to form the first reflection surface 1211. All regions except the light incident region and the light outgoing region in the outer surface of the emission waveguide 121 may be coated with a total reflection waveguide film, or attached with a reflection film or the like, to prevent the detection beam transmitted in the emission waveguide 121 being emitted out from a region other than the light outgoing region of the emission waveguide 121 and affecting the amount of outgoing detection beams. The foregoing light outgoing region refers to a region of the waveguide that is covered by the detection beam in the emission waveguide 121 when being reflected by the first reflection surface and then emitted outward. Likewise, the second reflection surface 1221 in the receiving waveguide 122 can also be manufactured in the foregoing manner, and the two reflection surfaces can be prepared simultaneously or separately. All regions except the light incident region in the outer surface of the receiving waveguide 122 may be coated with a total reflection waveguide film, or attached with a reflection film or the like, to prevent the echo beam transmitted in the receiving waveguide 122 being leaked from the region other than the light incident region of the receiving waveguide 122 and affecting the amount of echo beams received by the receiving module 600. The foregoing light incident region means that the echo beam enters the receiving waveguide 122 after passing through the light incident region and being incident on the second reflection surface.
The structure provided in this embodiment facilitates processing of the first reflection surface 1211 and a second emission surface 131, and makes an overall structure of the transceiving module compact and small in size.
In the foregoing embodiments, the transceiving assembly includes N emission waveguides and N receiving waveguides, where N≥1. In an embodiment, the same transceiving assembly includes one emission waveguide and N receiving waveguides. When one receiving waveguide is provided in the same transceiving assembly, the structure of the transceiving assembly is simple and production costs are relatively low. When there are multiple receiving waveguides, an area of the receiving surface of the transceiving assembly can be effectively increased, thereby improving the reception rate of the echo beam and the ranging capability of the LiDAR using the transceiving assembly. When the LiDAR provided in the foregoing embodiment is used for detection, the scanning module deflects the optical path to quickly scan the field of view to detect an object in the to-be-detected region. Due to relatively long time of flight of photons in long-distance detection, the scanning module has moved non-negligibly during this period of time; and a spatial orientation of the scanning module when receiving the echo beam is different from a spatial orientation when the detection beam is emitted, which causes a walkoff effect of a scanning receiving angle of the LiDAR. Offset caused by the walkoff effect of the receiving angle is related to the time of flight of photons. The longer the time, the larger the offset. Therefore, the offset of an echo beam returned after being reflected from an object at a greater distance is greater. The walkoff effect of the scanning receiving angle of the LiDAR mentioned herein is manifested in both the direction X and the direction Y. It can be known from the foregoing description that objects at different distances correspond to different time of flight of photons. For the LiDAR, due to a large ranging range of the LiDAR, offset of the echo beams also differs greatly, and a single receiving waveguide cannot effectively receive the echo beam within the entire ranging range, which affects the receiving efficiency. N receiving waveguides disposed in the transceiving assembly can correspond to echo beams with various offset, thereby improving receiving coupling efficiency of the transceiving assembly and further improving a ranging capability of the LiDAR.
In the foregoing embodiments, to ensure a good receiving effect of the receiving waveguides, a distance between the waveguides in the same transceiving assembly is less than 2 μm.
In an embodiment, multiple receiving waveguides are placed on either side or both sides of the emission waveguide in each transceiving assembly. As shown in
In an embodiment, in the same transceiving assembly, the first reflection surface of the emission waveguide and the second reflection surface of the receiving waveguide are aligned in the first direction, which facilitates an optical path design and simultaneous processing of the two reflection surfaces.
To further improve the reception rate of the echo beam and the coupling efficiency of coupling the echo beam to enter the receiving waveguide, on the basis of the foregoing embodiments, as shown in
The flared structure 123 in this embodiment is a structure whose width decreases along a transmission direction of the echo signal, and may be a tapered structure that changes uniformly or non-uniformly. The arrangement of the flared structure 123 enlarges the signal receiving surface of the receiving waveguide 122 in the first direction A. Under different scanning conditions, scanning speeds of the scanning apparatus are different, and therefore, the echo beams have different offset in the vertical direction, and the receiving waveguide 122 can still receive the echo beam with sufficient energy (provided that the minimum requirement for system receiving sensitivity is satisfied), which can further effectively alleviate impact of the walkoff effect of the receiving angle on the receiving efficiency of the FMCW LiDAR. Using the transceiving module 100 provided in this embodiment of the present application can effectively improve the efficiency of receiving the echo beam by the FMCW LiDAR, thereby ensuring the detection distance of the LiDAR.
The foregoing flared structure can be arranged into various forms. Referring to
In an embodiment, the receiving waveguide includes a multi-mode waveguide, a tapered transition waveguide, and a single-mode waveguide connected in sequence. The multi-mode waveguide and the tapered transition waveguide are combined to form the flared structure. The emission waveguide is the single-mode waveguide. In some other embodiments, for the multi-mode waveguide, a few-mode waveguide may also be used.
In an embodiment, as shown in
In an embodiment, as shown in
To improve the reflectivity of the transceiving module provided in the foregoing embodiments and reduce loss of light energy, in an embodiment, both the first reflection surface and the second reflection surface are coated with a high-reflection film.
In an embodiment, as shown in
In an embodiment, the first terminals of the multiple transceiver modules are located on the same plane, and the second terminals are located on the same plane. The first terminal is the terminal of the transceiving assembly that emits the detection beam and receives the echo beam, and the second terminal is the terminal of the transceiving assembly that receives the detection beam and outputs the echo beam. The facilitates production of the transceiving assembly, provided that both the first terminal and the second terminal are formed on the surface of the substrate.
In another embodiment, as shown in
On the basis of the foregoing embodiments, the second terminals of the multiple transceiving assemblies are located on the same plane. With this structure, the light incident terminals of all emission waveguides 121 and the light outgoing terminals of all receiving waveguides 122 are located on the same plane, which facilitates a design of a coupling packaging structure of the emission waveguide and the emission module, and a design of a coupling packaging structure of the receiving waveguide and the receiving module.
In another embodiment, as shown in
In conclusion, in the two embodiments corresponding to
Another embodiment of the present application provides a LiDAR, including an emission module 200, a scanning module 400, a receiving module 600, and the transceiving module 100 provided in the foregoing embodiment. The emission module 200 is configured to emit a detection beam, the transceiving module 100 is configured to receive the detection beam and emit the detection beam to the scanning module 400, and is also configured to receive the echo beam transmitted by the scanning module 400, and the scanning module 400 is configured to receive and reflect the detection beam to deflect the detection beam outwards to the to-be-detected region, and is also configured to receive and reflect the echo beam, so that the echo beam is polarized and then directed to the transceiving module 100. The receiving module 600 is configured to receive and process the echo signal transmitted by the transceiving module 100.
The emission module 200 in this embodiment may include a laser beam source. The laser source can be a DFB laser (Distributed Feedback Laser), an EEL laser (Edge Emitting Laser), a VCSEL (Vertical Cavity Surface Emitting Laser), or a laser source combining the DFB laser and the EDFA (Erbium-doped Optical Fiber Amplifier). A coupling manner of the emission module 200, the receiving module 600 and the transceiving module 100 may be fiber coupling, grating coupling, microlens coupling, or direct coupling. The receiving module 600 may include a combination of one or more of a receiver and a processing circuit, a receiving and processing chip, and a silicon optical coherent receiving chip.
As shown in
A working principle of the LiDAR provided in this embodiment is as follows.
The emission module 200 emits detection beams, and the detection beams are coupled to enter the transceiving module 100, are transmitted and emitted by the transceiving module 100 to the scanning module 400, are deflected by the scanning module 400 and are then emitted outwards to a to-be-detected region. Then, echo beams returned after being reflected by an object in the to-be-detected region are received by the scanning module 400, and the scanning module 400 deflects the echo beams and then emits the echo beams to the transceiving module 100. The echo beams are coupled to enter the transceiving module 100. The transceiving module 100 emits the echo beams to the receiving module 600, and the receiving module 600 performs calculation according to the received echo beams to obtain a detection result.
The LiDAR provided in the embodiments of the present application uses the transceiving module 100 provided in the foregoing embodiments, so that the LiDAR has multiple detection channels in the vertical direction, which can effectively improve resolution of the LiDAR in the vertical direction, and implement integration of transceiving functions without requiring a spatial optical circulator, thereby implementing a high degree of integration.
In an embodiment, as shown in
In an embodiment, as shown in
The frequency-modulated continuous-wave LiDAR further includes a signal processing module 800 for processing an echo electric signal output by the receiving module 600. The signal processing module 800 includes a signal adjustment circuit, a signal collection circuit, a signal processing circuit, an algorithm control circuit, an external interface, and the like.
The emission module 200 can emit the detection beams by using a fiber laser, the detection beams are coupled through one or more optical fibers to enter the emission waveguides 121 of the N transceiving assemblies of the transceiving module 100, the receiving waveguides 122 of the N transceiving assemblies receive the corresponding echo beams, and then the echo beams are coupled to enter the receiving module 600. The light-splitting module 700 splits the local oscillator beam into N parts to be coupled to enter the receiving module 600. The receiving module 600 includes N receiving paths, each receiving path respectively receives one local oscillator beam and one echo beam of the receiving waveguide 122, outputs the corresponding echo electric signal after frequency beating, and sends the echo electric signal to the signal processing module 800.
The foregoing descriptions are only exemplary embodiments of the present application, and only detail the technical principle of the present application. These descriptions are only used to explain the principle of the present application, and cannot be construed as a limitation on the protection scope of the present application in any method. Based on the illustration herein, any modification, equivalent replacement and improvement made within the spirit and principle of the present application, and another embodiment of the present application that can be derived by a person skilled in the art without creative efforts shall all fall within the protection scope of the present application.
Number | Date | Country | Kind |
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202211102152.3 | Sep 2022 | CN | national |
202211105845.8 | Sep 2022 | CN | national |