Optical chip

Abstract

The embodiment of the application discloses an optical chip, which comprises a cladding, a transmitting waveguide module and a receiving waveguide module, and the transmitting waveguide module and the receiving waveguide module are oppositely arranged. A first coupling area of the transmitting waveguide module and a second coupling area of the receiving waveguide module are configured to enable the light signal transmitted by the transmitting waveguide module to be coupled into the receiving waveguide module, and then the echo light received by the transmitting waveguide module can be coupled into the receiving waveguide module. According to the application, the receiving waveguide module can receive the echo light and transmit the echo light to the downstream photoelectric detection module, and the transmitting waveguide module can also receive the echo light and couple the received echo light into the receiving waveguide module to transmit the echo light to the downstream photoelectric detection module. Therefore, the embodiment of the application can improve the receiving efficiency of the echo light and reduce the field-of-view blind area of the laser radar.

Description

[0001] This application is a divisional application of Chinese application No. 202310370426.5, the foregoing contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of laser detection technology, and in particular to an optical chip. Background Technology

[0003] LiDAR is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle is to first emit a detection light towards the target, then compare the received echo light reflected back from the target with the local oscillator light, and after appropriate processing, obtain relevant information about the target, such as the target's distance, azimuth, altitude, velocity, attitude, and even shape.

[0004] Among them, Frequency Modulated Continuous Wave (FMCW) lidar combines frequency modulated continuous wave ranging with laser detection technology, offering advantages such as a large ranging range, high range resolution, and the ability to perform Doppler velocities. In recent years, small size and high integration have been the development trend of FMCW lidar, while the rapidly developing integrated photonics technology has also injected new vitality into frequency modulated continuous wave lidar.

[0005] FMCW lidar technologies typically employ scanning devices (e.g., galvanometer + rotating mirror) to ensure high beam quality and long transmission distance. However, as the lidar operates, the scanning device moves, causing the transmission paths of the probe light and the echo light to become inconsistent before and after passing through the scanning device. This results in a shift in the echo light, known as the walk-off effect, which affects the lidar's detection performance. Summary of the Invention

[0006] Some related technologies use optical chips to transmit and receive optical signals. For example, a transmitting waveguide module arranged on the optical chip emits probe light to the scanning device, and a receiving waveguide module arranged on the optical chip receives the echo light. The receiving waveguide module can be a single receiving waveguide or multiple receiving waveguides, thereby increasing the area that the receiving waveguide module can receive light. There is a gap between the receiving waveguide module and the transmitting waveguide module. When the target object is close to the lidar, the echo light may fall on the transmitting waveguide module, causing the receiving waveguide module to fail to receive the echo light, thus creating a certain close-range detection blind zone for the lidar.

[0007] This application provides an optical chip to improve the current situation where LiDAR has a certain blind spot for short-range detection.

[0008] In a first aspect, embodiments of this application provide an optical chip, including a cladding layer, a transmitting waveguide module, and a receiving waveguide module. The transmitting waveguide module is embedded in the cladding layer and extends along a first direction. The transmitting waveguide module transmits probe light and outputs it to the outside of the optical chip. The first direction is perpendicular to the thickness direction of the optical chip. The receiving waveguide module is embedded in the cladding layer and receives the echo light reflected back from the target object by the probe light. One end of the transmitting waveguide module emitting the probe light and the other end of the receiving waveguide module receiving the echo light are located at the same end of the optical chip. Viewed along the thickness direction, the transmitting waveguide module and the receiving waveguide module are arranged opposite each other along a second direction, where any two of the second direction, the first direction, and the thickness direction are perpendicular to each other. The transmitting waveguide module has a first coupling region, and the receiving waveguide module has a second coupling region. Viewed along the thickness direction, the first coupling region and the second coupling region are arranged opposite each other along the second direction. The first coupling region and the second coupling region are configured to allow the optical signal transmitted by the transmitting waveguide module to couple into the receiving waveguide module.

[0009] Secondly, embodiments of this application provide a lidar, including the aforementioned optical chip.

[0010] Thirdly, embodiments of this application provide an autonomous driving system, including the aforementioned lidar.

[0011] Fourthly, embodiments of this application provide a mobile device including the aforementioned lidar; or, the aforementioned autonomous driving system.

[0012] In this application, the optical chip, lidar, autonomous driving system, and mobile device are configured such that the first coupling region of the transmitting waveguide module and the second coupling region of the receiving waveguide module can couple the optical signal transmitted by the transmitting waveguide module into the receiving waveguide module. Thus, not only can the receiving waveguide module receive echo light for transmission to downstream photodetector modules, but the transmitting waveguide module can also receive echo light and couple it into its receiving waveguide module for transmission to downstream photodetector modules. Therefore, the embodiments of this application can improve the reception efficiency of echo light and reduce the blind zone of the lidar. Furthermore, since the distance between the sides of the transmitting and receiving waveguide modules is generally less than or approximately equal to the mode field size of the echo light, when the echo spot is located between the transmitting and receiving waveguide modules, it will fall on at least one of them. Therefore, the above configuration helps to completely eliminate the near-range detection blind zone of the lidar. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the mobile device provided in the embodiments of this application;

[0015] Figure 2 This is a schematic block diagram of the structure of the mobile device provided in the embodiments of this application;

[0016] Figure 3 This is a perspective structural diagram of the optical chip provided in an embodiment of this application;

[0017] Figure 4 This is a schematic diagram of the first structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in this application embodiment;

[0018] Figure 5 This is a schematic diagram of a second structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in this application embodiment;

[0019] Figure 6 This is a schematic diagram of the third structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0020] Figure 7 This is a schematic diagram of the fourth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0021] Figure 8 This is a schematic diagram of the fifth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0022] Figure 9 This is a sixth structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0023] Figure 10 This is a seventh structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0024] Figure 11 This is an eighth structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0025] Figure 12 This is a ninth structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0026] Figure 13 This is a schematic diagram of the tenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0027] Figure 14 This is an eleventh structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0028] Figure 15 This is a schematic diagram of the twelfth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0029] Figure 16 This is a thirteenth structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0030] Figure 17 This is the fourteenth structural schematic diagram of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0031] Figure 18 This is a schematic diagram of the fifteenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0032] Figure 19 yes Figure 18 The diagram shows the optical power curves of the echo light output from each output port of the receiving waveguide module to the back end when the optical chip detects a target object within a range of 0-250m.

[0033] Figure 20 yes Figure 18 The diagram shows the optical power curves of the echo light output from each output port of the receiving waveguide module to the back end when the optical chip does not have a second coupling region and detects a target object within a range of 0-250m.

[0034] Figure 21 This is a schematic diagram of the sixteenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0035] Figure 22 This is a schematic diagram of the structure of the input receiving waveguide and beam combiner of the receiving waveguide module in the optical chip provided in this application embodiment;

[0036] Figure 23 This is a schematic diagram of the seventeenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0037] Figure 24A This is a schematic diagram of the eighteenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0038] Figure 24B This is a schematic diagram of the nineteenth structure of the transmitting waveguide module and the receiving waveguide module in the optical chip provided in the embodiments of this application;

[0039] Figure 25 yes Figure 24A This diagram shows the structure of the transmitting waveguide module in the optical chip.

[0040] Figure 26 yes Figure 25 The grayscale image shows a schematic diagram of the optical field propagation of the transmitting waveguide module when used to transmit probe light.

[0041] Figure 27 yes Figure 26 The grayscale image shows a schematic diagram of the mode evolution of the transmitting waveguide module when used to transmit probe light.

[0042] Figure 28 This is a schematic diagram of beam transmission using a single-emitting waveguide in a single-input, single-output configuration in related technologies.

[0043] Figure 29 This is a schematic diagram of beam transmission using the transmitting waveguide module in this embodiment under single-input multiple-output conditions;

[0044] Figure 30 yes Figure 28 The grayscale image shown is of the far-field spot of the emitted beam falling on the target object corresponding to the single-emitting waveguide in the related technology.

[0045] Figure 31 yes Figure 29 The image shown is a grayscale image of the far-field spot of the emitted beam that falls on the target object corresponding to the transmitting waveguide module of this embodiment.

[0046] Figure 32 This is a perspective structural diagram of the transmitting waveguide module in an optical chip provided in some other embodiments of this application;

[0047] Figure 33 yes Figure 32 The diagram shown is a schematic of the transmitting waveguide module in the optical chip.

[0048] Figure 34 This is a schematic diagram of an architecture of a lidar provided in an embodiment of this application;

[0049] Figure 35 This is a schematic diagram of another LiDAR architecture provided in an embodiment of this application.

[0050] Explanation of reference numerals in the attached figures: 1. Mobile device; 2. Autonomous driving system; 3. LiDAR; 4. Optical chip; 41. Transmitting waveguide module; 411. First coupling region; 412. First transmitting waveguide; 412m. Incident end; 412n. Exit end; 4121. First input section; 4121p. First part; 4121q. Second part; 4122. First coupling section; 4123. First output section; 4124. First transmission section; 4125. Third coupling section; 413. Second transmitting waveguide; 4131. Second coupling section; 4132. Second output section; 4133. Second transmission section; 4134. Fourth coupling section; 42. Substrate layer; 43. Cladding layer; 44. Receiving waveguide module; 441. Second coupling region; 4411. First sub-section; 4412. Second sub-section; 4413. Third sub-section ; 442, Receiving waveguide; 4421, First end; 4422, Second end; 4423, First receiving waveguide; 4424, Second receiving waveguide; 4427, First connecting part; 4428, Third end; 4429, Second connecting part; 4420, Fourth end; 443, Beam combiner; 4431, First beam combiner; 4432, Second beam combiner; 4433, Third beam combiner; 444, First transmitting waveguide; 45, Phase compensator; c, First interface; d, Second interface; e, Third interface; f, Fourth interface; s, Fifth interface; t, Sixth interface; 6, Scanning device; 71, First coupler; 72, Second coupler; 73, Splitter; 74, Mixer; 75, Balanced photodetector; x, First direction; y, Second direction; z, Thickness direction; 412', First transmitting waveguide. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0052] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0053] Please see Figure 1 and Figure 2 This application provides a mobile device 1, which includes a LiDAR 3; or, the mobile device 1 includes an autonomous driving system 2. The mobile device 1 can be any device including a car, drone, robot, etc., that includes either a LiDAR 3 or an autonomous driving system 2. When the mobile device 1 includes an autonomous driving system 2, the autonomous driving system 2 includes the LiDAR 3.

[0054] Among them, LiDAR 3 can be a Frequency Modulated Continuous Wave (FMCW) LiDAR, etc., and there is no limitation on this. FMCW LiDAR can be widely used in intelligent connected vehicles, vehicle-to-everything (V2X) communication, intelligent robots and other scenarios.

[0055] Specifically, see Figure 3 The lidar 3 includes an optical chip 4, which receives the detection light generated by the light source module (not shown in the figure) within the lidar 3 and outputs the detection light outside the optical chip 4 to detect target objects within the detection area. Furthermore, the optical chip 4 can also receive the echo light reflected back from the target object; then, it compares the echo light with the local oscillator light and outputs the corresponding electrical signal; subsequently, the signal processing unit within the lidar 3 processes the electrical signal appropriately to form a point cloud map; next, further processing of the point cloud map yields parameters such as the target object's distance, orientation, height, speed, attitude, and shape, thereby realizing the laser detection function. This can be applied to navigation and avoidance, obstacle recognition, ranging, speed measurement, and autonomous driving scenarios in products such as automobiles, robots, logistics vehicles, and inspection vehicles.

[0056] Depending on actual needs, in addition to the field of laser detection technology, LiDAR 3 can also be used in other application scenarios, such as part diameter detection, surface roughness detection, strain detection, displacement detection, vibration detection, velocity detection, distance detection, acceleration detection, and object shape detection.

[0057] For the aforementioned optical chip 4, please refer to Figure 3 The diagram illustrates a schematic of an optical chip 4 provided in one embodiment of this application. The optical chip 4 includes a cladding layer 43, a transmitting waveguide module 41, and a receiving waveguide module 44. The cladding layer 43 constitutes one of the main structures of the optical chip 4 and is also the structure on which the transmitting waveguide module 41 and the receiving waveguide module 44 are attached. The cladding layer 43 can be made of materials such as silicon dioxide and / or silicon oxynitride.

[0058] The transmitting waveguide module 41 is used to transmit the detection light generated by the light source module inside the lidar 3 and output it to the outside of the optical chip 4 for detection of target objects. The transmitting waveguide module 41 is embedded in the cladding 43 and extends along the first direction x shown in the figure. The refractive index of the transmitting waveguide module 41 is greater than that of the cladding 43. Thus, the transmitting waveguide module 41 and the cladding 43 together constitute a structure for stable light transmission, that is, light can be transmitted along the transmitting waveguide module 41 and is not easily leaked out of the optical chip 4 via the cladding 43. For example, when the cladding 43 is made of silicon dioxide, the transmitting waveguide module 41 can be made of silicon nitride, which has a higher refractive index, or it can be made of other materials with a higher refractive index than the cladding 43, such as silicon. It is worth noting that the "first direction" mentioned in this application means the extension direction of the transmitting waveguide module 41, which is perpendicular to the thickness direction z of the optical chip 4. The thickness direction of the optical chip 4 is the same as the thickness direction of the cladding 43.

[0059] The receiving waveguide module 44 is used to receive the echo light formed by the detection light reflected from the target object and transmit it to the photoelectric detection module. The receiving waveguide module 44 is embedded in the cladding 43, and the refractive index of the receiving waveguide module 44 is greater than that of the cladding 43. Thus, the receiving waveguide module 44 and the cladding 43 together constitute a structure for stable light transmission, that is, light can be transmitted along the receiving waveguide module 44 and is not easily leaked out of the optical chip 4 via the cladding 43. For example, when the cladding 43 is made of silicon dioxide, the receiving waveguide module 44 can be made of silicon with a higher refractive index, or it can be made of other materials with a higher refractive index than the cladding 43, such as silicon nitride.

[0060] The optical chip 4 may further include a substrate layer 42, with a cladding layer 43 deposited or grown on the substrate layer 42. The substrate layer 42 is the substrate for laying the cladding layer 43. In this embodiment, it is made of silicon. It is understood that in other embodiments of this application, the substrate layer 42 may also be made of other suitable materials, such as silicon oxynitride. The material of the substrate layer 42 is generally different from that of the cladding layer 43. It is worth noting that the substrate layer 42 is intended to support the cladding layer 43 during the manufacturing process of the optical chip 4; in some cases, the substrate layer 42 can be omitted.

[0061] In this embodiment, both the transmitting waveguide module 41 and the receiving waveguide module 44 are embedded in the cladding 43, forming an integrated transceiver unit. The distance between them is small, allowing them to share a lens module / scanning device, and eliminating the need for optical components such as birefringent crystals or circulators, thus greatly simplifying the system architecture. In some embodiments, the distance between the transmitting waveguide module 41 and the receiving waveguide module 44 is less than 20 micrometers.

[0062] Next, the transmitting waveguide module 41 and the receiving waveguide module 44 will be described in detail.

[0063] Please continue reading. Figure 3 The transmitting waveguide module 41 extends along the first direction x shown in the figure, where "first direction" in this application refers to the extension direction of the transmitting waveguide module 41, which is perpendicular to the thickness direction z of the optical chip 4. Viewed along the thickness direction z, the receiving waveguide module 44 and the transmitting waveguide module 41 are positioned opposite each other along the second direction y shown in the figure, with one end of the transmitting waveguide module 41 emitting probe light (…). Figure 3 The left end shown is connected to the end of the receiving waveguide module 44 that receives the echo light. Figure 3 The left end shown is located at the same end of the optical chip 4; that is, the optical chip 4 is configured to emit probe light and receive echo light at the same end. The transmitting waveguide module 41 and the receiving waveguide module 44 are configured to couple the echo light received by the transmitting waveguide module 41 into the receiving waveguide module 44. Here, the "second direction" mentioned in this application means a direction that is simultaneously perpendicular to both the thickness direction z and the first direction x, i.e., any two of the second direction, the first direction, and the thickness direction are perpendicular to each other.

[0064] Since the lidar 3 includes a scanning device, this scanning device can rotate relative to the lidar 3 housing or the optical chip 4. The scanning device is located downstream of the transmitting waveguide module 41 along the transmission direction of the detection light, to receive the detection light emitted via the transmitting waveguide module 41 and emit it outside the lidar 3, thereby forming a detection field of view outside the lidar 3 to detect target objects within this field of view. The scanning device can scan in the vertical and / or horizontal directions. The scanning device can be any device capable of changing the light propagation path, such as a MEMS galvanometer or a rotating mirror; there is no limitation on this.

[0065] During the operation of the lidar 3, the scanning device may move (e.g., rotate), causing the transmission paths of the probe light and echo light to become inconsistent before and after passing through the scanning device. The echo light may not re-enter the transmitting waveguide module 41, instead shifting relative to it, resulting in the aforementioned walk-off effect. This walk-off effect causes the focused spot of the echo light to shift along the second direction y. The amount of this shift (dy) is approximately proportional to the distance (S) of the target object. Thus, the shift of the echo light from distant targets is relatively large, while the shift of the echo light from nearby targets is relatively small. When the echo light falls on the receiving waveguide module 44, the receiving waveguide module 44 can receive the echo light and transmit it downstream. Because there is a gap between the transmitting waveguide module 41 and the receiving waveguide module 44, when the target object is close to the lidar 3, the spot of the echo light may fall on the transmitting waveguide module 41 or the gap between the transmitting waveguide module 41 and the receiving waveguide module 44, thus not being received by the receiving waveguide module 44, or the echo light power received by the receiving waveguide module 44 is extremely small, resulting in a near-range detection blind zone for the lidar 3.

[0066] In this embodiment, the transmitting waveguide module 41 and the receiving waveguide module 44 are configured such that the optical signal transmitted by the transmitting waveguide module 41 is coupled into the receiving waveguide module 44. Thus, not only can the receiving waveguide module 44 receive the echo light for transmission to the downstream photodetector module, but the transmitting waveguide module 41 can also receive the echo light and couple it into the receiving waveguide module 44 for transmission to the downstream photodetector module. Therefore, this embodiment can improve the echo light reception efficiency and reduce the blind zone of the lidar 3. Furthermore, since the distance between the transmitting waveguide module 41 and the receiving waveguide module 44 is generally less than or approximately equal to twice the mode field size of the echo light, when the echo spot is located between the transmitting waveguide module 41 and the receiving waveguide module 44, it will fall on at least one of them. Therefore, the above arrangement is beneficial to completely eliminate the near-range detection blind zone of the lidar 3. The distance between the transmitting waveguide module 41 and the receiving waveguide module 44 is the distance between the center of the waveguide closest to the receiving waveguide module in the transmitting waveguide module and the center of the waveguide closest to the transmitting waveguide module in the receiving waveguide module.

[0067] In this embodiment, please refer to Figure 4 , Figure 4A schematic diagram of a transmitting waveguide module 41 and a receiving waveguide module 44 according to one embodiment of this application is shown. The transmitting waveguide module 41 has a first coupling region 411, and the receiving waveguide module 44 has a second coupling region 441. Viewed along the thickness direction z, the first coupling region 411 and the second coupling region 441 are arranged opposite each other along the second direction y. The second coupling region 441 is bent towards the transmitting waveguide module 41 relative to the adjacent portion of the receiving waveguide module 441 located upstream of the second coupling region 441, so that the first coupling region 411 and the second coupling region 441 are configured to couple the optical signal transmitted by the transmitting waveguide module 41 into them. It should be noted that in the embodiments of this application, upstream and downstream are defined with reference to the transmission direction of the same optical signal. The component that the same optical signal passes through first is located upstream of the component that passes through later. For example, the adjacent portion of the receiving waveguide module 44 located upstream of the second coupling region 441 refers to the portion that the same echo light passes through before passing through the second coupling region 441 when passing through the receiving waveguide module 44.

[0068] Next, the specific structure of the receiving waveguide module 44 will be described in detail.

[0069] In this embodiment, the receiving waveguide module 44 includes at least two receiving waveguides 442. Each receiving waveguide 442 includes a first end 4421 and a second end 4422 disposed opposite to each other. The first end 4421 receives echo light, allowing it to enter the receiving waveguide module 44, while the second end 4422 transmits the echo light downstream through the medium. The receiving waveguides 442 are spaced apart along the second direction y. For ease of explanation, the receiving waveguide 442 adjacent to the transmitting waveguide module 41 in the receiving waveguide module 44 is defined as the first receiving waveguide 4423, and the remaining receiving waveguides are defined as the second receiving waveguides 4424. In this embodiment, the first receiving waveguide 4423 has the second coupling region 441, which bends towards the transmitting waveguide module 41 relative to its upstream portion. Correspondingly, the transmitting waveguide module 41 has a first coupling region 411 disposed opposite to the second coupling region 441. As described above, the first coupling region 411 and the second coupling region 441 are configured to allow the light transmitted by the transmitting waveguide module 41 to enter the first receiving waveguide 4423, so that the echo light reflected by the nearby target object is received by the transmitting waveguide module 41 and then enters the first receiving waveguide 4423 through the first coupling region 411 and the second coupling region 441.

[0070] This application does not specifically limit the extended shape of the second coupling region 441; for example, the second coupling region 441 may extend in a curved shape as a whole, or the second coupling region 441 may include a curved extension portion and a straight extension portion. The curve may include an arc, or the curve may include at least two arcs connected in sequence, with adjacent arcs having different radii of curvature. The straight line may be parallel to or intersect the second direction y, without limitation.

[0071] To reduce optical loss, the second coupling region 441 can be smoothly connected to other parts of the first receiving waveguide 4423; if the extended shape of the second coupling region 441 includes at least two arcs connected in sequence, the two adjacent arcs can be smoothly connected; if the extended shape of the second coupling region 441 includes a straight line and an arc connected in sequence, the straight line and the arc can be smoothly connected.

[0072] If the transmitting waveguide module 41 and the receiving waveguide module 44 are coupled through the second coupling region 441, the coupling ratio between the transmitting waveguide module 41 and the receiving waveguide module 44 can be adjusted by changing the shape of the second coupling region 441 and the relative positional relationship between the second coupling region 441 and the transmitting waveguide module 41. For example, the coupling ratio can be adjusted by changing the spacing between the second coupling region 441 and the first coupling region 411, the extension length of the second coupling region 441 along the first direction x, etc. The spacing between the second coupling region 441 and the first coupling region 411 can be the minimum spacing between the second coupling region 441 and the first coupling region 411 along the second direction y.

[0073] For example, if the second coupling region 441 includes a first sub-part 4411, a second sub-part 4412, and a third sub-part 4413 connected in sequence, the second sub-part 4412 is located on the side of the first sub-part 4411 close to the first coupling region 411, the second sub-part 4412 is located on the side of the third sub-part 4413 close to the first coupling region 411, and the extension direction of the second sub-part 4412 is approximately consistent with the extension direction of the first transmitting waveguide module 41, that is, the second sub-part 4412 extends approximately along the first direction x, then the distance between the second coupling region 441 and the first coupling region 411 can be: the distance between the second sub-part 4412 and the first coupling region 411.

[0074] The first sub-part 4411 and the second sub-part 4412 can be smoothly connected, as can the first sub-part 4411 and other parts of the first receiving waveguide 4423. The third sub-part 4413 and the second sub-part 4412 can be smoothly connected, as can the third sub-part 4413 and other parts of the first receiving waveguide 4423. The first sub-part 4411 can extend in a curved shape as a whole, or it can include both curved and straight sections. The second sub-part 4412 can extend in a curved shape as a whole, or it can include both curved and straight sections.

[0075] The arrangement of multiple receiving waveguides 442 is beneficial for increasing the area of ​​the receiving waveguide module 44 that can receive light along the second direction y, which in turn helps to improve the overall detection range of the lidar 3. In this embodiment, the receiving waveguide module 44 includes at least three receiving waveguides 442, one of which is the aforementioned first receiving waveguide 4423, and the remaining two or more are second receiving waveguides 4424, with each receiving waveguide 442 arranged sequentially along the aforementioned second direction y. Generally, each receiving waveguide 442 needs to be connected to a separate photoelectric detection module downstream to detect the echo light output from the receiving waveguide 442 and the local oscillator light transmitted inside the lidar 3; and each photoelectric detection module also needs to be connected to a signal processing module to process the electrical signal converted by the photoelectric detection module. Thus, as the number of receiving waveguides 442 increases, the number of photoelectric detection modules and signal processing modules also increases, which significantly increases the device cost of the lidar 3.

[0076] To overcome the above shortcomings, in this embodiment, the receiving waveguide module 44 further includes at least one beam combiner 443. The beam combiner 443 includes two input terminals and one output terminal. Its input terminals are used to connect to the receiving waveguide 442 to combine the two receiving waveguides 442. Specifically, please refer to... Figure 5 The at least one beam combiner 443 includes a first beam combiner 4431. Each input terminal of the first beam combiner 4431 is connected to a second receiving waveguide 4424, i.e., connected to a receiving waveguide 442 other than the first receiving waveguide 4423. The output terminal of the first beam combiner 4431 is connected to a first transmission waveguide 444. In this way, the echo light received by the two receiving waveguides 442 connected to the beam combiner 443 will be output to the downstream photoelectric detection module via the first transmission waveguide 444. This arrangement can reduce the number of photoelectric detection modules and the processing of the aforementioned signal processing module, thereby reducing the overall cost of the lidar 3 to a certain extent.

[0077] When there are a large number of receiving waveguides 442, please refer to Figure 6The second receiving waveguide 4424 connected to the first beam combiner 4431 can also be configured on the side facing the first receiving waveguide 4423; similarly, please refer to Figure 7 The second receiving waveguide 4424 connected to the first beam combiner 4431 can also be configured on the side opposite to the first receiving waveguide 4423. The number of first beam combiners 4431 can be as follows: Figures 5 to 7 One shown can also be like Figure 8 As shown, multiple receiving waveguides 442 are set up when there are a large number of them.

[0078] Please see Figure 9 When the receiving waveguide module 44 includes at least four receiving waveguides 442, the at least one beam combiner 443 may further include a second beam combiner 4432. Specifically, the first beam combiner 4431 and the second beam combiner 4432 are connected in series. Taking at least one beam combiner 443 including a second beam combiner as an example, the two input terminals of the first beam combiner 4431 are respectively connected to a second receiving waveguide 4424, and the output terminal is connected to a first transmission waveguide 444; one input terminal of the second beam combiner 4432 is connected to the upstream beam combiner 443, i.e., the output terminal of the first beam combiner 4431, through the first transmission waveguide 444, and the other input terminal is connected to another second receiving waveguide 442, and the output terminal of the second beam combiner 4432 is connected to a first transmission waveguide 444. In this configuration, the receiving waveguides 442 connected to the first beam combiner 4431 and the second beam combiner 4432 are adjacent, meaning the three receiving waveguides 442 connected to the two beam combiners 443 are sequentially adjacent. Thus, the echo light received via these three receiving waveguides 442 will be transmitted downstream to the photodetector module via the first transmission waveguide 444 at the output of the second beam combiner 4432, further reducing the number of photodetector modules. The number of second beam combiners 4432 can be as follows: Figure 9 One shown; or it can be as shown Figure 10 Specifically, the first beam combiner 4431 and multiple second beam combiners 4432 are connected in series. One input end of the second beam combiner is connected to the output end of the upstream beam combiner 443 through the first transmission waveguide 444, and the other input end is connected to another second receiving waveguide 442. The output end of the second beam combiner 4432 is connected to a first transmission waveguide 444, and the receiving waveguides 442 connected to two adjacent beam combiners 443 are adjacent.

[0079] Furthermore, considering that the detection distance of the receiving waveguide 442 is also greater the farther it is from the transmitting waveguide module 41, and the lower the energy of the received echo light, and that the echo light may suffer a certain proportion of loss after passing through the combiner 443, it is possible to ensure that the receiving waveguide 442 connected to the downstream combiner 443 is farther from the transmitting waveguide module 41 than the receiving waveguide 442 connected to the upstream combiner 443. This reduces the number of combiners 443 that the long-distance echo light passes through, thereby reducing the loss of the long-distance echo light in the receiving waveguide module 44 and ensuring that the final output energy meets the requirements. In addition, since the energy of the short-distance echo light is higher, even if it passes through a large number of combiners 443, the energy output by the receiving waveguide module 44 can still meet the requirements.

[0080] It is worth mentioning that if the echo light falls simultaneously on the two receiving waveguides 442 connected to the two adjacent combiners 443, for example... Figure 10 As shown at the first ends 4421 of the two bottommost receiving waveguides 442, the number of beam combiners 443 they pass through when the echo photon signals received by each receiving waveguide 442 finally reach the same beam combiner 443 for beam combining is different, thus resulting in phase differences. These phase differences can lead to optical power loss; for example, when the phase difference reaches π, coherent destructive phases may occur. To overcome this deficiency, the optical chip 4 also includes a phase compensator 45. A phase compensator 45 is provided between the two beam combiners 443 connected in series. The phase compensator 45 is used to compensate for the phase change that occurs when the echo light passes through the upstream beam combiner 443, eliminating the phase difference and reducing optical power loss.

[0081] It should be understood that although this embodiment is described with the beam combiner 443 connected to the second receiving waveguide 4424 as an example, this application is not limited to this. In other embodiments of this application, the beam combiner 443 may also be connected to the first receiving waveguide 4423.

[0082] For example, please see Figure 11 The receiving waveguide module 44 includes two or more receiving waveguides 442, and at least one beam combiner 443 includes a first beam combiner 4431. This embodiment is similar to... Figure 5 The main difference in the illustrated embodiment is that one input terminal of the first beam combiner 4431 is connected to the first receiving waveguide 4423, the other input terminal is connected to the receiving waveguide 442 adjacent to the first receiving waveguide 4423, and its output terminal is connected to a first transmission waveguide 444. Furthermore, since the first beam combiner 4431 is connected to the first receiving waveguide 4423, and... Figure 5Compared to the previous embodiment, this embodiment can further reduce the number of final output ports of the receiving waveguide module 44, thereby helping to reduce the device cost of the lidar 3. The number of first beam combiners 4431 can be one, or multiple can be set when the number of receiving waveguides 442 is large.

[0083] It should be noted that, since the first receiving waveguide 4423 has a second coupling region 441, and the portion of the second coupling region 441 is bent towards the transmitting waveguide module 41 relative to the upstream portion, the lengths of the first receiving waveguide 4423 and the second receiving waveguide 4424 connected to the first combiner 4431 may be different. However, if the lengths of the two receiving waveguides 442 connected to the same combiner 443 are different, the echo light transmitted to the combiner 443 will have a phase difference. Therefore, the lengths of the multiple receiving waveguides 442 connected to the same combiner 443 can be designed to satisfy the following: the phase difference of each receiving waveguide 442 transmitted to the same combiner 443 is an integer multiple of the wavelength of the probe light, etc., in order to eliminate the phase difference and reduce optical power loss. It is understandable that the phase difference effect of multiple receiving waveguides 442 connected to the same combiner 443 can also be eliminated by means of a phase compensator. The phase compensator can be set in the receiving waveguide 442 connected to the same combiner 443 that does not have a second coupling region 441, so as to avoid the disadvantage of complex structure caused by setting the second coupling region 441 and the phase compensator at the same receiving waveguide 442. Of course, there are many ways to eliminate the above phase difference, and this application does not limit it.

[0084] For example, please see Figure 12 The receiving waveguide module 44 includes three or more receiving waveguides 442, and at least one beam combiner 443 includes a first beam combiner 4431 and a second beam combiner 4432. This embodiment is similar to... Figure 9 The main difference in the illustrated embodiment is that one input terminal of the first beam combiner 4431 is connected to the first receiving waveguide 4423, and the other input terminal is connected to the receiving waveguide 442 adjacent to the first receiving waveguide 4423. Furthermore, since the first beam combiner 4431 is connected to the first receiving waveguide 4423, and... Figure 9 Compared to the embodiment shown, this embodiment can further reduce the number of final output ports of the receiving waveguide module 44, thereby helping to reduce the device cost of the lidar 3.

[0085] For example, see Figure 13 The receiving waveguide module 44 includes two or more receiving waveguides 442, and at least one beam combiner 443 includes a first beam combiner 4431. This embodiment is similar to... Figure 11The main difference in the illustrated embodiment is that the first receiving waveguide 4423 does not have the aforementioned second coupling region 441, which is located in the first transmission waveguide 444 connected to the output of the beam combiner 443. Specifically, one input of the first beam combiner 4431 is connected to the first receiving waveguide 4423, and the other input is connected to the receiving waveguide 442 adjacent to the first receiving waveguide 4423. The output of the first beam combiner 4431 is connected to the first transmission waveguide 444, which has the aforementioned second coupling region 441. The second coupling region 441 is located downstream of the first beam combiner 4431. This arrangement helps reduce the number of beam combiners 443 that the return light coupled from the transmitting waveguide module 41 to the receiving waveguide module 44 passes through, thereby reducing the loss of the return light. Lower optical loss also allows for a more appropriate reduction in the coupling efficiency between the transmitting and receiving waveguide modules 41 and 44, enabling a smaller coupling ratio to meet the coupling requirements between them. This ensures that the probe light emitted from the transmitting waveguide module 41 has high energy. The number of first beam combiners 4431 can be one, or... Figure 14 As shown, when there are many receiving waveguides 442, multiple ones are set accordingly. In this case, only the first beam combiner closest to the transmitting waveguide module is connected to the first receiving waveguide and the second receiving waveguide, while the remaining first beam combiners are connected to two second receiving waveguides.

[0086] For example, please see Figure 15 The receiving waveguide module 44 includes three or more receiving waveguides 442, and at least one beam combiner 443 includes a first beam combiner 4431 and at least one second beam combiner 4432 connected in series. This embodiment is similar to... Figure 12The main difference in the illustrated embodiment is that the first receiving waveguide 4423 does not have the aforementioned second coupling region 441, which is located in the first transmission waveguide 444 connected to the output of the combiner 443. Specifically, one input of the first combiner 4431 is connected to the first receiving waveguide 4423, and the other input is connected to the receiving waveguide 442 adjacent to the first receiving waveguide 4423. The output of the first combiner 4431 is connected to the first transmission waveguide 444. One input of the second combiner 4432 is connected to the upstream combiner 443 through the first transmission waveguide 444, and the other input is connected to a receiving waveguide 442. The output of the second combiner 4432 is connected to the first transmission waveguide 444. The receiving waveguides 442 connected to the inputs of each combiner 443 are different. Except for the first receiving waveguide 4423, the receiving waveguides 442 connected to adjacent combiners 443 are adjacent to each other. The first transmission waveguide 444 connected to the output end of the first beam combiner 4431 is provided with a second coupling region 441, and / or the first transmission waveguide 444 connected to the output end of the second beam combiner 4432 is provided with a second coupling region 441. The arrangement of the second coupling region 441 downstream of the first beam combiner 4431 helps to reduce the number of beam combiners 443 that the return light coupled from the transmitting waveguide module 41 into the receiving waveguide module 44 passes through, thereby reducing the loss of the return light.

[0087] Based on all the above embodiments, when the receiving waveguide module 44 includes a first beam combiner 4431 and at least two second beam combiners 4432, the direction in which the first beam combiner 4431 and at least two second beam combiners 4432 are connected in series in the receiving waveguide module 44 may not be consistent with the arrangement direction of each receiving waveguide 442. For example, combining... Figure 16 and Figure 17 At least two second combiners 4432 are connected to receiving waveguides 442 which can be located on opposite sides of the receiving waveguide 442 connected to the first combiner 4431 along the second direction y. In this case, the series connection direction of the first combiner 4431 and each second combiner 4432 is as shown in the figure, first up and then down, or first down and then up, rather than always down or always up.

[0088] Based on all the above embodiments, when the number of receiving waveguides 442 is at least two more than the number of beam combiners 443, along the second direction y, the receiving waveguide 442 furthest from the transmitting waveguide module 41 is not connected to a beam combiner 443, such as... Figure 18 As shown. This ensures that the echo light corresponding to the farthest detection distance, after being received by the receiving waveguide 442, can be directly transmitted to the photoelectric detection module without passing through the combiner 443, thus ensuring that the energy of the echo light finally reaching the photoelectric detection module meets the requirements.

[0089] Furthermore, if the receiving waveguide module 44 includes Figure 18 The diagram shows five receiving waveguides 442 and two first beam combiners 4431. One input of one first beam combiner 4431 is connected to a first receiving waveguide 4423, and the other input is connected to a second receiving waveguide 4424 adjacent to the first receiving waveguide 4423. The two inputs of the other first beam combiner are respectively connected to a second receiving waveguide 4424. Along the second direction y, the receiving waveguide 442 furthest from the transmitting waveguide module 41 is not connected to a beam combiner 443. Of the two first beam combiners 4431, the first beam combiner connected to the first receiving waveguide 4423 is... The first transmission waveguide 444 connected to the output end of the beam combiner 4431 has a second coupling region 441. When the lidar 3 detects a target object within a 0-250m range, the optical power of the echo light output to the rear end of the first transmission waveguide 444 connected to the output end of the first beam combiner 4431 (which is connected to the first receiving waveguide 4423), the first transmission waveguide 444 not connected to the first receiving waveguide 4423, and the receiving waveguide 442 not connected to the beam combiner 4431 are respectively as follows: Figure 19 Regions O1, O2, and O3 are shown in the diagram. And if... Figure 18 The receiving waveguide module 44 shown no longer has a second coupling region 441. The first transmission waveguide 444 connected to the first beam combiner 4431 that connects to the first receiving waveguide 4423, the first transmission waveguide 444 connected to the first beam combiner 4431 that does not connect to the first receiving waveguide 4423, and the receiving waveguide 442 that is not connected to the beam combiner 443, the optical power of the return light output to the back end are respectively as follows: Figure 20 As shown in regions O1', O2', and O3', by Figure 19 and Figure 20 It can be seen that, by setting the second coupling region 441 on the receiving waveguide module 44, the embodiment of this application can significantly improve the echo light power received by the lidar 3 at the near target object, thereby improving the detection performance of the lidar 3 at the near target object.

[0090] Alternatively, the aforementioned at least one bundler 443 may also include at least two first bundlers 4431 and at least one third bundler 4433. For details, please refer to [link to relevant documentation]. Figure 21The two input terminals of the third beam combiner 4433 are respectively connected to a first beam combiner 4431 via a first transmission waveguide 444. The output terminal of the third beam combiner 4433 is connected to a first transmission waveguide 444. At this time, at least one of the first receiving waveguide 4423, the first transmission waveguide 444 to which the output terminal of the first beam combiner 4431 connected to the first receiving waveguide 4423 is connected, and the first transmission waveguide 444 to which the output terminal of the third beam combiner 4433 is connected can have a second coupling region 441. The receiving waveguides 442 connected to the two first beam combiners 4431 connected to the same third beam combiner 4433 can be adjacent.

[0091] The specific positions of each beam combiner can be set as follows: Along the second direction y, the two input ends of the first beam combiner 4431 can be located between the first ends 4421 of the two connected receiving waveguides 442, so that the second ends 4422 of the two connected receiving waveguides 442 can extend in a direction closer to each other, reducing the size of the receiving waveguide module 44 along the second direction y. Along the second direction y, the two input ends of the second beam combiner 4432 are located on the side of the connected receiving waveguide 442 facing the first beam combiner 4431, reducing the size of the receiving waveguide module 44 along the second direction y. For example, the two input ends of the second beam combiner 4432 are located between the second end 4422 of the connected receiving waveguide 442 and the output end of the upstream beam combiner 443. Along the second direction y, the two input ends of the third combiner 4433 are located between the two connected first transmission waveguides 444, so that the second ends 4422 of the two receiving waveguides 442 connected to the first combiner 4431 can extend in a direction that approaches each other, reducing the size of the receiving waveguide module 44 along the second direction y.

[0092] The specific structure of the aforementioned receiving waveguide will be explained in detail below. For example, please refer to [link / reference needed]. Figure 22 The receiving waveguide 442 includes a first connecting portion 4427, which includes a first end 4421 and a third end 4428 opposite to the first end 4421. From the first end 4421 to the third end 4428, the cross-sectional profile of the first connecting portion 4427 gradually expands. That is, the end face size of the first end 4421 used to receive the echo light is small, and the end face size away from the first end 4421 is large. The small end face size helps to ensure a larger mode field diameter and improve the light receiving tolerance of the receiving waveguide 442, while the gradually increasing aperture can transition to a size where light can propagate stably.

[0093] It should be noted that the cross-sectional profile of the first connecting portion 4427 gradually expands from the first end 4421 to the third end 4428. This expansion could be due to the width of the first connecting portion 4427 gradually expanding along the second direction y, etc., and is not limited thereto. The cross-sectional profile of the first connecting portion 4427 can increase steadily with a fixed slope from the first end 4421 to the third end 4428, or it can increase with a varying slope; this is not limited thereto. In the embodiment of this application, the cross-sectional profile of the first connecting portion 4427 increases steadily with a fixed slope from the first end 4421 to the third end 4428, and the first connecting portion 4427 is approximately conical.

[0094] The first connecting portion 4427 can extend in a straight line or in a curved direction. In this embodiment, the first connecting portion 4427 of each input receiving waveguide 442 extends in a straight line, and the extension directions of the first connecting portion 4427 of each input receiving waveguide 442 are approximately parallel. Further, the extension direction of the first connecting portion 4427 of each input receiving waveguide 442 can be approximately at an angle to the second direction y. The angle between the extension direction of the first connecting portion 4427 of each input receiving waveguide 442 and the second direction y can be 75°, 85°, 90°, 95°, etc., and is not limited thereto.

[0095] See Figure 22 The receiving waveguide 442 also includes a second connecting portion 4429, which includes a fourth end 4420 and a second end 4422. The fourth end 4420 is connected to the third end 4428. From the fourth end 4420 to the second end 4422, the cross-sectional profile of the second connecting portion 4429 remains constant. It is worth mentioning that the first connecting portions 4427 of each input receiving waveguide 442 have the same shape and are aligned, which helps to ensure that the mode field diameter of each input receiving waveguide 442 at the light receiving position is consistent, and that the variation law of the mode field diameter of each input receiving waveguide 442 is consistent. However, for the second connecting portions 4429, due to the access of the beam combiner 443, the ends of each second connecting portion 4429 that are away from the first connecting portion 4427 are generally misaligned.

[0096] The second connecting portion 4429 can be configured to extend along a smooth curve to reduce light loss.

[0097] The beam combiner 443 in this embodiment can be any device capable of combining at least two optical signals before outputting them. For example, the beam combiner 443 can be a multi-mode interference (MMI) coupler, a Y-coupler, a star coupler, etc.

[0098] The spacing between the first ends 4421 of two adjacent receiving waveguides 442 can be approximately within twice the mode field diameter of the receiving waveguide 442, i.e., L ≤ 2D. Here, the spacing between the first ends 4421 of two adjacent receiving waveguides 442 means the distance between the centers of the first ends 4421 of the two adjacent receiving waveguides 442. Specifically, the spacing between the first ends 4421 of two adjacent receiving waveguides 442 can be the sum of half the width of the first end 4421 of one receiving waveguide 442 along the second direction y, half the width of the first end 4421 of the other receiving waveguide 442 along the second direction y, and the gap between the two receiving waveguides 442 along the second direction y. The mode field diameter of the first end 4421 of the receiving waveguide 442 means the diameter of the area where the first end 4421 can receive optical signals, which can be determined by obtaining the mode field diameter of the light at the first end 4421 when the optical signal is transmitted from the second end 4422 to the first end 4421. Generally, the mode field diameter of the receiving waveguide 442 is approximately the same as that of the echo light, thus ensuring high coupling efficiency when receiving the echo light; and the spacing between the first ends 4421 of two adjacent receiving waveguides 442 is approximately within twice the mode field diameter of the receiving waveguide 442, thus ensuring that no matter where the echo light spot falls on the receiving waveguide module 44, it can be coupled into at least one receiving waveguide 442.

[0099] Specifically, the mode field diameter of the first end 4421 of the receiving waveguide 442 is a first diameter D, and the distance between the first ends 4421 of two adjacent receiving waveguides 442 is a first distance L. The optical chip 4 can satisfy: 0.6≤L / D≤2.0. Optionally, the value of D / L can be 0.6, 0.65, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, etc., and is not limited thereto.

[0100] Furthermore, the aforementioned L / D ≥ 0.6 setting also ensures that the echo light is received by at most two receiving waveguides 442. That is, the echo light is received by only one receiving waveguide 442 or only by two adjacent receiving waveguides 442, thereby reducing signal processing complexity.

[0101] It should be noted that the spacing between the first ends 4421 of two adjacent receiving waveguides 442 can be designed by simulation based on factors such as detection efficiency; for example, the mode field between the first ends 4421 of the receiving waveguide 442 can be designed to be approximately equal to the optical mode field diameter of the corresponding echo light, so as to ensure that the receiving waveguide 442 has better optical coupling efficiency.

[0102] Furthermore, to achieve optical coupling between the transmitting waveguide module 41 and the receiving waveguide module 44, in addition to bending the second coupling region 441 towards the transmitting waveguide module 41, the first coupling region 411 of the transmitting waveguide module 41 can also be bent relative to other parts of the transmitting waveguide module 41 adjacent to the first coupling region 411 towards the receiving waveguide module 44, so that the first coupling region 411 and the second coupling region 441 are configured to allow optical signals transmitted by the transmitting waveguide module 41 to couple into each other. Of course, the first coupling region 411 and the second coupling region 441 can also be configured as described above simultaneously.

[0103] Additionally, it should be noted that if the echo light received by the transmitting waveguide module 41 can couple into the receiving waveguide module 44, then when the transmitting waveguide module 41 transmits the probe light, at least a portion of the probe light transmitted within the transmitting waveguide module 41 will also couple into the receiving waveguide module 44. Therefore, to avoid the mutual coupling between the transmitting waveguide module 41 and the receiving waveguide module 44 affecting the optical energy of the probe light output by the optical chip 4 of the transmitting waveguide module 41, the coupling between the transmitting waveguide module 41 and the receiving waveguide module 44 can be weak coupling, such that the coupling ratio between the transmitting waveguide module 41 and the receiving waveguide module 44 satisfies the following: the probe light output by the transmitting waveguide module 41 has sufficient optical energy to meet the detection requirements, and the echo light coupled into the receiving waveguide module 44 by the transmitting waveguide module 41 meets the signal processing requirements.

[0104] Specifically, the coupling ratio between the transmitting waveguide module 41 and the receiving waveguide module 44 is α; where α can be flexibly adjusted according to actual conditions. For example, α can be greater than or equal to 0.1% and less than or equal to 1%; specifically, the above coupling ratio α can be 0.1%, 0.3%, 0.6%, 0.8%, 1%, etc., without limitation. For example, if the coupling ratio α between the transmitting waveguide module 41 and the receiving waveguide module 44 is 1%, then only 1% of the optical signal transmitted in the transmitting waveguide module 41 can couple into the receiving waveguide module 44.

[0105] The above is a detailed description of the receiving waveguide module 44. Next, the construction of the transmitting waveguide module 41 in this embodiment will be specifically described. The implementation of the transmitting waveguide module 41 is actually diverse. It can adopt a single waveguide transmitting probe light scheme or a multi-waveguide transmitting probe light scheme; the former scheme is more conventional, and the latter technical scheme will be described in detail below.

[0106] Please see Figure 23 If the transmitting waveguide module 41 includes at least two transmitting waveguides, the transmitting waveguide closest to the receiving waveguide module 44 has a first coupling region 411.

[0107] Further, please refer to Figure 24A The system includes at least two transmitting waveguides, including a first transmitting waveguide 412 and at least one second transmitting waveguide 413. The first transmitting waveguide 412 has an incident end 412m and an exit end 412n opposite each other along its extension direction. The incident end 412m is used to receive probe light. Viewed along the thickness direction z, the second transmitting waveguide 413 and the first transmitting waveguide 412 are arranged opposite each other along a second direction y. The first transmitting waveguide 412 and the second transmitting waveguide 413 are configured to couple the probe light in the first transmitting waveguide 412 into the second transmitting waveguide 413, so that the transmitting waveguide module 41 outputs a probe light beam through at least two transmitting waveguides. That is, the transmitting waveguide module 41 of this embodiment can achieve single waveguide input and multiple waveguide output. It is worth mentioning that, given the diversity of application scenarios, the optical chip 4 may directly receive the probe light output by the light source module through the first transmitting waveguide 412, that is, the first transmitting waveguide is a single waveguide structure, and the incident end 412 is at the end position in the single waveguide structure; the optical chip may also indirectly receive the probe light output by the light source module through the first transmitting waveguide 412, for example, other waveguide structures are connected upstream of the first transmitting waveguide 412, that is, the transmitting waveguide is a part in the middle of the entire waveguide structure.

[0108] The second transmitting waveguide 413 and the first transmitting waveguide 412 are arranged opposite each other as follows: the extension direction of the second transmitting waveguide 413 is approximately the same as the extension direction of the first transmitting waveguide 412, and the two are arranged opposite each other in a direction approximately perpendicular to the extension direction of the first transmitting waveguide 412.

[0109] It is understood that the transmitting waveguide module 41 is configured to output probe light through at least two transmitting waveguides. This can be that the transmitting waveguide module 41 is configured to output a probe light through the first transmitting waveguide 412 and the second transmitting waveguide 413, or it can be that the transmitting waveguide module 41 is configured to output a probe light through two or more second transmitting waveguides 413. This application does not limit this.

[0110] In this embodiment, the transmitting waveguide module 41 is configured to output a probe beam via a first transmitting waveguide 412 and a second transmitting waveguide 413 as an example for illustrative purposes. The number of second transmitting waveguides 413 can be one, two, three, etc., and this application does not limit this. If the probe beam is output from the transmitting waveguide module 41 via one first transmitting waveguide 412 and two or more second transmitting waveguides 413, the two or more second transmitting waveguides 413 can be arranged in a circular array around the periphery of the first transmitting waveguide 412, allowing the probe beam transmitted through the first transmitting waveguide 412 to couple more smoothly into the peripheral second transmitting waveguides 413.

[0111] The aforementioned two or more transmitting waveguides may include a first transmitting waveguide 412 and at least one second transmitting waveguide 413. Please continue reading. Figure 24A and Figure 25 The first transmitting waveguide 412 includes a first input portion 4121 and a first coupling portion 4122. Along the first direction x shown in the figure, the first input portion 4121 is located upstream of the first coupling portion 4122 and extends beyond the second transmitting waveguide 413. The end of the first input portion 4121 facing away from the first coupling portion 4122 is the aforementioned incident end 412m. This first input portion 4121 is used to receive probe light via the incident end 412m, so that the probe light enters the first transmitting waveguide 412 and propagates along it. It is worth noting that the "first direction x" mentioned in this application refers to the extension direction of the first transmitting waveguide 412 from the incident end 412m to the exit end 412n.

[0112] Along the first direction x, the first coupling portion 4122 is located downstream of the first input portion 4121 to transmit probe light entering the first transmitting waveguide 412 via the first input portion 4121. Correspondingly, the second transmitting waveguide 413 includes a second coupling portion 4131. Viewed along the thickness direction z, the second coupling portion 4131 and the first coupling portion 4122 are arranged opposite each other along the second direction y. The first coupling portion 4122 and the second coupling portion 4131 are configured to allow probe light in the first coupling portion 4122 to couple into the second coupling portion 4131. In this embodiment, along the first direction x, the cross-sectional profile of the first coupling portion 4122 gradually shrinks, for example, the width of the first coupling portion 4122 gradually decreases; the cross-sectional profile of the second coupling portion 4131 remains constant. Thus, the first coupling portion 4122 and the second coupling portion 4131 together constitute a module that can realize optical coupling. During the transmission of light in the first coupling portion 4122, light will overflow into the second coupling portion 4131. Specifically, by limiting the cross-sectional profile of the first coupling part 4122 along the first direction x, the probe light in the first coupling part 4122 can overflow, and the overflowed probe light can enter the second transmitting waveguide 413, thereby realizing the output of the probe light from multiple transmitting waveguides. Since the probe light is transmitted from one transmitting waveguide to the first transmitting waveguide 412 and the second transmitting waveguide 413, the mode field size of the probe light will increase; and according to the following formula (1) which roughly satisfies the divergence angle θ and the mode field radius ω0 of the beam output, the increase of the mode field of the probe light can realize the reduction of the divergence angle of the output beam, which is beneficial to improving the resolution of the lidar 3 during detection.

[0113] θ=λ / (πω0) (1)

[0114] In some embodiments, when viewed along a direction perpendicular to the optical chip 4, the width of the first coupling portion 4122 along the first direction x can gradually decrease from b0 to b1, where b0 > b1, 0.5 μm ≤ b0 ≤ 1.2 μm, and 0.2 μm ≤ b1 ≤ 0.9 μm. Along the first direction x, the width of the second coupling portion 4131 can remain unchanged; specifically, the width of the second coupling portion 4131 can be a0, where 0.1 μm ≤ a0 ≤ 0.4 μm.

[0115] Regarding the spacing between the first coupling portion 4122 and the second coupling portion 4131 along the first direction x, this spacing can remain constant. Specifically, along the first direction x, the spacing between the first coupling portion 4122 and the second coupling portion 4131 can be maintained at g1, where 0.2μm≤g1≤1.2μm; this satisfies both manufacturing process requirements and allows for optical coupling between the first coupling portion 4122 and the second coupling portion 4131. It should be noted that the spacing between the first coupling portion 4122 and the second coupling portion 4131 as described in this application refers to the spacing between the centerline of the first coupling portion 4122 and the centerline of the second coupling portion 4131. Furthermore, the centerline of a component described in this application satisfies the following conditions: the extension direction of the centerline is consistent with the extension direction of the component, and the width of the component is the same on both sides of the centerline.

[0116] Please see Figure 24A A second transmitting waveguide 413 located between the first transmitting waveguide 412 and the receiving waveguide module 44 has a first coupling region 411. Specifically, the first coupling region 411 is located at the second coupling portion 4131 of the second transmitting waveguide 413. Of course, in some other embodiments, the first coupling region 411 may also be located at the first input portion 4121 of the first transmitting waveguide 412, as shown in the example below. Figure 24B As shown, the first coupling region 411 is located at a position that does not correspond to the second transmitting waveguide 413, thus having minimal impact on the transmission of the probe light by the transmitting waveguide module 41, and ensuring the mode field symmetry of the emitted probe light.

[0117] In this embodiment, the first transmitting waveguide 412 further includes a first output section 4123, which is located downstream of the first coupling section 4122 along the first direction x. The second transmitting waveguide 413 further includes a second output section 4132 disposed opposite to the first output section 4123, which is located downstream of the second coupling section 4131 along the first direction x. The transmitting waveguide module 41 is configured to output probe light via the first output section 4123 and the second output section 4132. In this embodiment, the transmitting waveguide module 41 includes one first transmitting waveguide 412 and two second transmitting waveguides 413, with the two second transmitting waveguides 413 located on opposite sides of the first transmitting waveguide 412. The probe light is output from the first transmitting waveguide 412 and the two second transmitting waveguides 413. Optionally, the two second transmitting waveguides 413 can be located on opposite sides of the first transmitting waveguide 412 along the width direction of the first transmitting waveguide 412, so as to reduce the divergence angle of the emitted beam from the transmitting waveguide module 41 along the width direction of the first transmitting waveguide 412; of course, in other embodiments, the arrangement direction between the transmitting waveguides may not be consistent with the width direction of the first transmitting waveguide 412. Furthermore, even though this embodiment is described using the transmitting waveguide module 41 outputting probe light via the first output section 4123 and the second output section 4132 as an example, it should be understood that this application is not limited to this, as long as the probe light is output jointly via the first transmitting waveguide 412 and the second transmitting waveguide 413; for example, in other embodiments of this application, the transmitting waveguide module 41 may also output probe light via the aforementioned first coupling section 4122 and the second coupling section 4131.

[0118] Optionally, the width of the first output portion 4123 can remain unchanged along the first direction x; the width of the second output portion 4132 can also remain unchanged along the first direction x. For example, along the first direction x, the width of the first output portion 4123 is kept at b2, and the width of the second output portion 4132 is kept at a1, where 0.1μm≤b2≤0.35μm and 0.1μm≤a1≤0.35μm.

[0119] Regarding the spacing between the second output section 4132 and the first output section 4123 along the first direction x, this spacing can be gradually increased to further expand the mode field size of the emitted detection light, thereby reducing the divergence angle of the emitted detection light and improving the resolution of the lidar 3 during detection. The spacing between the second output section 4132 and the first output section 4123 along the first direction x can increase steadily at a fixed slope or at a varying slope; there is no limitation on this. In this embodiment, along the first direction x, the rate of change of the distance between the second output portion 4132 and the first output portion 4123 gradually increases and then decreases. Specifically, along the first direction x, the distance between the second output portion 4132 and the first output portion 4123 first increases by a small amount, then by a larger amount, and then by a smaller amount again. This ensures that the first output portion 4123 is directly and smoothly connected to its upstream portion, thereby achieving mode field expansion of the emitted beam while reducing probe light loss. Simultaneously, it ensures that the transmission direction of the probe light output via the first output portion 4123 is consistent with the transmission direction of the probe light output via the second output portion 4132, and that the overall extension shape of the first output portion 4123 changes smoothly. It should be noted that the distance between the second output portion 4132 and the first output portion 4123 as described in this application refers to the distance between the centerline of the second output portion 4132 and the centerline of the first output portion 4123.

[0120] In some embodiments, along the first direction x, the distance between the second output portion 4132 and the first output portion 4123 gradually changes from g1 to g2, where g2>g1 and 1μm≤g2≤3μm.

[0121] Optionally, if the transmitting waveguide module 41 includes two or more second transmitting waveguides 413, the spacing variation pattern between the second output portion 4132 and the first output portion 4123 of each second transmitting waveguide 413 along the first direction x can be kept consistent, so that the amount of detection light in each second transmitting waveguide 413 can be relatively balanced, thereby reducing the light intensity difference in various parts of the light spot formed by the emitted beam and improving the detection performance of the lidar 3. Specifically, each second output portion 4132 can be distributed in a circular array around the first output portion 4123, and the shape of each second output portion 4132 can be approximately the same.

[0122] In this embodiment, the first transmitting waveguide 412 may further include a first transmission section 4124, which is connected to the first coupling section 4122 along the first direction x and is located downstream of the first coupling section 4122. The second transmitting waveguide 413 may further include a second transmission section 4133 disposed opposite to the first transmission section 4124, which is connected to the second coupling section 4131 along the first direction x and is located downstream of the second coupling section 4131. Along the first direction x, the cross-sectional profile of the first transmission section 4124 gradually shrinks, and the cross-sectional profile of the second transmission section 4133 gradually shrinks. This arrangement aims to further expand the mode field size of the probe light when it is transmitted through the first transmission section 4124 and the second transmission section 4133 by shrinking the width of each transmitting waveguide. Thus, when the probe light passes through the first coupling section 4122, part of the optical signal is coupled into the second coupling section 4131, and the mode field size of the probe light initially increases; when the probe light passes through the first transmission section 4124 and the second transmission section 4133, the mode field size of the probe light further increases; when the probe light passes through the first output section 4123 and the second output section 4132, the mode field size of the probe light increases even further; in other words, the mode field size of the probe light increases three times, thus enabling it to have a larger mode field size at emission, thereby ensuring a smaller divergence angle at emission.

[0123] Along the first direction x, the width of the first transmission section 4124 can decrease smoothly at a fixed rate of change or decrease at a varying slope; this is not limited. Similarly, along the first direction x, the width of the second transmission section 4133 can decrease smoothly at a fixed slope or decrease at a varying slope; this is not limited. Optionally, the width variation pattern of the first transmission section 4124 and the width variation pattern of the second transmission section 4133 along the first direction x can be approximately the same. For example, in some embodiments, along the first direction x, the width of the first transmission section 4124 can gradually decrease from b1 to b2; along the first direction x, the width of the second transmission section 4133 can gradually decrease from a0 to a1 at the end connecting it to the second output section 4132. It should be noted that in this embodiment, the first coupling part 4122 and the first output part 4123 are indirectly connected through a first transmission part 4124 with varying width; therefore, b2 is less than b1. Of course, in other embodiments of this application, if the first coupling part 4122 and the first output part 4123 are directly connected, then b2 can be equal to b1. Similarly, in this embodiment, the second coupling part 4131 and the second output part 4132 are indirectly connected through a second transmission part 4133 with varying width; therefore, a1 is less than a0. Of course, in other embodiments of this application, if the second coupling part 4131 and the second output part 4132 are directly connected, then a1 can be equal to a0.

[0124] Regarding the spacing between the first transmission unit 4124 and the second transmission unit 4133, it can be that the spacing between the first transmission unit 4124 and the second transmission unit 4133 remains unchanged along the first direction x. Specifically, the spacing between the first transmission unit 4124 and the second transmission unit 4133 can be maintained at g1 along the first direction x. It should be noted that the spacing between the first transmission unit 4124 and the second transmission unit 4133 as described in this application means the spacing between the center line of the first transmission unit 4124 and the center line of the second transmission unit 4133.

[0125] In this embodiment, the first transmitting waveguide 412 further includes a third coupling portion 4125; along the first direction x, the third coupling portion 4125 is connected to the first coupling portion 4122 and located upstream of the first coupling portion 4122. Correspondingly, the second transmitting waveguide 413 further includes a fourth coupling portion 4134 disposed opposite to the third coupling portion 4125; along the first direction x, the fourth coupling portion 4134 is connected to the second coupling portion and located upstream of the second coupling portion 4131; the third coupling portion 4125 and the fourth coupling portion 4134 are configured such that the probe light in the third coupling portion 4125 is coupled into the fourth coupling portion 4134. In this embodiment, along the aforementioned first direction x, the distance between the fourth coupling portion 4134 and the third coupling portion 4125 gradually decreases. For example, along the first direction x, the distance between the third coupling portion 4125 and the fourth coupling portion 4134 can be gradually reduced to g1. The arrangement of gradually narrowing the distance between the third coupling part 4125 and the fourth coupling part 4134 is intended to enable the probe light to begin initial coupling at the third coupling part 4125 and the fourth coupling part 4134, thereby overcoming the high coupling loss caused by directly starting coupling at the first coupling part 4122 and the second coupling part 4131.

[0126] Optionally, the width of the third coupling portion 4125 can remain constant along the first direction x. For example, the width of the third coupling portion 4125 can be maintained at b0 along the first direction x. The width of the fourth coupling portion 4134 can remain constant along the first direction x. For example, the width of the fourth coupling portion 4134 can be maintained at a0 along the first direction x. The width of the fourth coupling portion 4134 can be less than the minimum width of the third coupling portion 4125.

[0127] Regarding the change in the distance between the third coupling portion 4125 and the fourth coupling portion 4134 along the first direction x, it can decrease steadily at a fixed rate of change or decrease at a varying rate of change; there is no limitation on this. In this embodiment, the rate of change of the distance between the third coupling portion 4125 and the fourth coupling portion 4134 along the first direction x increases and then decreases again. That is, along the first direction x, the distance between the third coupling portion 4125 and the fourth coupling portion 4134 first decreases by a small amount, then decreases by a larger amount, and then decreases by a smaller amount again. This allows for a gradual approach between the first transmitting waveguide 412 and the second transmitting waveguide 413 in the first direction x, thereby improving the coupling efficiency between the first transmitting waveguide 412 and the second transmitting waveguide 413.

[0128] Further, in this embodiment, the first input section 4121 includes a first portion 4121p and a second portion 4121q connected to each other. Along the first direction x, the first portion 4121p has the aforementioned incident end 412m, through which it receives the probe light generated by the light source module. The second portion 4121q is connected to the end of the first portion 4121p opposite to the incident end 412m and is located upstream of the first coupling section 4122. It is used to transmit the probe light to the third coupling section 4125 and the first coupling section 4122. The width of the first portion 4121p can remain constant, while the width of the second portion 4121q can gradually decrease; for example, the width of the second portion 4121q can be gradually reduced until the width of the end opposite to the first portion 4121p is b0. This configuration is designed so that after receiving the probe light, the width of the first input section 4121 can be varied to match the width of the downstream waveguide structure, so as to transmit the probe light to the downstream waveguide structure. For example, the optical chip 4 also includes a waveguide structure located upstream of the first input section 4121. The width of the first part 4121p is the same as the width of the upstream waveguide structure, and the width of the second part 4121q, which is opposite to the width of the first part 4121p, is the same as the width of the downstream waveguide structure. In this way, the first input section 4121 can couple the probe light into the downstream waveguide structure in a way with low loss.

[0129] The first transmitting waveguide 412 can extend in a straight line, allowing the second transmitting waveguide 413 to adjust the spacing between the second transmitting waveguide 413 and the first transmitting waveguide 412 by bending or other changes relative to the first transmitting waveguide 412. This reduces the design difficulty of the transmitting waveguide module 41 and improves production efficiency.

[0130] The above describes the structure of the transmitting waveguide module 41. Next, taking the transmitting waveguide module 41 comprising a first transmitting waveguide 412 and two second transmitting waveguides 413 respectively disposed on both sides of the first transmitting waveguide 412 as an example, and referring to the attached diagram... Figures 25 to 31The divergence of the detection light output by the optical chip 4 in this embodiment and related technologies will be explained.

[0131] As described above, the first transmitting waveguide 412 may include a first input section 4121, a third coupling section 4125, a first coupling section 4122, a first transmission section 4124, and a first output section 4123 connected sequentially along the first direction x. The second transmitting waveguide 413 may include a fourth coupling section 4134, a second coupling section 4131, a second transmission section 4133, and a second output section 4132 connected sequentially along the first direction x. The interface between the first part 4121p and the second part 4121q is denoted as the first interface c, the interface between the second part 4121q and the third coupling section 4125 is denoted as the second interface d, the interface between the third coupling section 4125 and the first coupling section 4122 is denoted as the third interface e, the interface between the first coupling section 4122 and the first transmission section 4124 is denoted as the fourth interface f, the interface between the first transmission section 4124 and the first output section 4123 is denoted as the fifth interface s, and the emitting end face of the first output section 4123 is denoted as the sixth interface t. The end face of the fourth coupling part 4134 facing away from the second coupling part 4131 can be coplanar with the second interface d. The interface between the fourth coupling part 4134 and the second coupling part 4131 can be coplanar with the third interface e. The interface between the second coupling part 4131 and the second transmission part 4133 can be coplanar with the fourth interface f. The interface between the second transmission part 4133 and the second output part 4132 can be coplanar with the fifth interface s. The emission end face of the second output part 4132 can be coplanar with the sixth interface t.

[0132] Optionally, the first interface c, the second interface d, the third interface e, the fourth interface f, the fifth interface s, and the sixth interface t can be parallel to each other or intersect each other, without any limitation.

[0133] Figure 26 The image shown is a grayscale diagram illustrating the optical field propagation of the transmitting waveguide module 41 when used to transmit probe light. Figure 27 A grayscale image of the mode evolution of the transmitting waveguide module 41 when used to transmit probe light is shown, wherein the mode at the first interface c is denoted as mode 1, the mode at the fourth interface f is denoted as mode 2, the mode at the fifth interface s is denoted as mode 3, and the mode at the sixth interface t is denoted as mode 4; Figure 26 and Figure 27It can be seen that mode 1 at the first interface c is the fundamental mode, while mode 2 at the fourth interface f and mode 3 at the fifth interface s have gradually evolved into the basic modes of the composite waveguide. The mode field size of mode 2 increases with the intersection of mode 1 and mode 3 increases further compared to mode 2. The mode field size of mode 4 at the sixth interface t increases further compared to mode 3. Thus, the mode field size of the probe light emitted by the transmitting waveguide module 41 is significantly larger than that of the initial received probe light. According to the above relationship between the divergence angle and the mode field size, the increase in the mode field size is beneficial to reducing the divergence angle of the emitted beam, thereby improving the resolution of the lidar 3 during detection.

[0134] Further, please refer to Figure 28 and Figure 29 , Figure 28 This diagram illustrates beam transmission in a single-input, single-output configuration using a single transmitting waveguide (i.e., only the first transmitting waveguide 412'). Figure 29 This diagram illustrates beam transmission using the transmitting waveguide module 41 in this embodiment with a single waveguide input and multiple waveguide outputs. Figure 29 The transmitting waveguide module 41 shown contains a transmitting waveguide for detecting optical input and... Figure 28 The single-emitting waveguides in the related technologies shown employ substantially the same width, and Figure 29 The transmitting waveguide module 41 shown is... Figure 28 The single-emitting waveguide shown, under the same fundamental mode energy injection, Figure 28 The far-field spot of the emitted beam from the single-emitting waveguide falling on the target object (such as a car, pedestrian, or calibration target) is shown below. Figure 30 As shown, Figure 29 The emitted beam from the transmitting waveguide module 41 shown is the spot of light falling on the target object. Figure 31 As shown, by Figure 30 and Figure 31 It can also be seen that the single waveguide input and multiple waveguide output of the transmitting waveguide module 41 in this application embodiment have a smaller far-field spot size than the single input and single output of the single transmitting waveguide in the related art. This also shows that the divergence angle of the detection light output by the transmitting waveguide module 41 provided in this application embodiment is smaller, which is beneficial to improving the resolution of the lidar 3 during detection.

[0135] Please continue reading. Figure 29The scanning device 6 is located downstream of the optical path of the transmitting waveguide module 41. It receives the probe light emitted from the optical chip 4 and deflects it in one or two dimensions to form a specific detection field of view outside the lidar 3. Because the divergence angle of the emitted beam from the transmitting waveguide module 41 is reduced, the spot size of the emitted beam reaching the scanning device 6 can be reduced, allowing the small-sized scanning device 6 to meet the application requirements. This is beneficial for the miniaturization and integration of the lidar 3. The scanning device 6 can be a galvanometer and / or a rotating mirror, etc., and is not limited thereto.

[0136] If the transmitting waveguide module 41 includes two or more second transmitting waveguides 413, the two or more second transmitting waveguides 413 can be spaced apart around the periphery of the first transmitting waveguide 412 around the extension direction of the first transmitting waveguide 412, so that the probe light transmitted by the first coupling part 4122 of the first transmitting waveguide 412 can be coupled into the second coupling part 4131 of the peripheral second transmitting waveguide 413.

[0137] It should be noted that the specific structure of the aforementioned transmitting waveguide module 41 can be adjusted according to the required divergence angle. For example, the number of transmitting waveguides included in the transmitting waveguide module 41 and the spacing between the second transmitting waveguide 413 and the first transmitting waveguide 412 can be adjusted according to the required divergence angle, and there is no limitation on this. Specifically, while keeping the spacing between the second transmitting waveguide 413 and the first transmitting waveguide 412 constant, the number of transmitting waveguides included in the transmitting waveguide module 41 can be increased to make the divergence angle of the emitted beam from the transmitting waveguide module 41 smaller. Specifically, while keeping the number of transmitting waveguides included in the transmitting waveguide module 41 constant, the spacing between the second transmitting waveguide 413 and the first transmitting waveguide 412 can be increased to make the divergence angle of the emitted beam from the transmitting waveguide module 41 smaller.

[0138] It should be noted that an anti-reflection coating can be deposited on the exit end face of the transmitting waveguide module 41 to reduce the reflectivity at the exit end face and improve the beam emission efficiency.

[0139] It should be noted that, in this embodiment, the first transmitting waveguide 412 includes a first input section 4121, a third coupling section 4125, a first coupling section 4122, a first transmission section 4124, and a first output section 4123. However, in some cases, one or more of the aforementioned first input section 4121, third coupling section 4125, first transmission section 4124, and first output section 4123 can be omitted; correspondingly, one or more of the fourth coupling section 4134, second transmission section 4133, and second output section 4132 in the second transmitting waveguide 413 can be omitted. For example, in some embodiments, the transmitting waveguide module 41 can receive probe light via the first coupling section 4122 and output probe light via the first coupling section 4122 and the second coupling section 4131.

[0140] In summary, the mobile device 1 provided in this application embodiment includes a lidar 3, which further includes an optical chip 4. The optical chip 4 includes a cladding 43 and a transmitting waveguide module 41, wherein the transmitting waveguide module 41 is used to receive probe light and output it outside the optical chip. The transmitting waveguide module 41 includes at least two transmitting waveguides, specifically including a first transmitting waveguide 412 and at least a second transmitting waveguide 413. The transmitting waveguide module 41 is configured to receive probe light via the first transmitting waveguide 412 and output probe light via the at least two transmitting waveguides. By employing a single transmitting waveguide to input probe light and multiple transmitting waveguides to output probe light, this application embodiment achieves a larger mode field size for the probe light emitted from the transmitting waveguide module 41, thereby reducing the divergence angle of the emitted probe light. This, in turn, helps to reduce the spot size of the probe light falling on the target object, thus improving the detection resolution.

[0141] Furthermore, the above description is based on the example that the end of the receiving waveguide module 44 that receives the echo light and the end of the transmitting waveguide module 41 that emits the echo light are located at the same end of the optical chip 4; however, it should be understood that in other embodiments of this application, the end of the receiving waveguide module 44 that receives the echo light and the end of the transmitting waveguide module 41 that emits the echo light may also be located at different ends of the optical chip 4. In this case, it is necessary to set up an optical element to separate the transmitting optical path and the echo optical path for beam splitting, such as an optical circulator, or a combination of light guide elements such as a birefringent crystal and a reflector.

[0142] Regarding the aforementioned transmitting waveguide module 41, it is worth mentioning that even though the above embodiment is described using the example of the transmitting waveguide module 41 outputting probe light through the first transmitting waveguide 412 and the second transmitting waveguide 413, this application is not limited to this. As long as the transmitting waveguide module 41 receives the probe light through the first transmitting waveguide 412 and outputs a beam of probe light through at least two transmitting waveguides, it is acceptable.

[0143] For example, Figure 32 and Figure 33 A schematic diagram of a transmitting waveguide module provided in another embodiment of this application is shown. The transmitting waveguide module 41 outputs probe light via at least two transmitting waveguides, specifically, the transmitting waveguide module 41 outputs probe light via at least two second transmitting waveguides 413. Compared to Figure 25 In the embodiment shown, the transmitting waveguide module 41 outputs probe light via the first transmitting waveguide 412 and the second transmitting waveguide 413. In this embodiment, the first transmitting waveguide 412 no longer outputs probe light.

[0144] Specifically, in this embodiment, the transmitting waveguide module 41 and Figure 25 The transmitting waveguide module 41 in the illustrated embodiment has a roughly the same structure, the difference being that: the first transmitting waveguide 412 in this embodiment is compared to... Figure 25 In the illustrated embodiment, the first output section 4123 is no longer provided for the first transmitting waveguide 412. Thus, along the first direction x, the second output section 4132 of each second transmitting waveguide 413 extends beyond the first transmitting waveguide 412; therefore, the transmitting waveguide module 41 can output probe light via the second output section 4132 of each second transmitting waveguide 413.

[0145] Similar to the transmitting waveguide module 41 in the above embodiment, the transmitting waveguide module 41 in this embodiment can also increase the mode field size when the probe light is emitted, thereby reducing the divergence angle of the probe light and improving the resolution of the lidar 3 during detection.

[0146] After explaining the transmitting waveguide module 41 and the receiving waveguide module 44, the architecture of the lidar 3, which includes the transmitting waveguide module 41 and the receiving waveguide module 44, will be briefly described next.

[0147] Please see Figure 34 and Figure 35 The lidar 3 can include more than one signal processing channel, for example, Figure 34 The diagram shows that the lidar 3 includes four signal processing channels, but this is not limited. Each signal processing channel includes a transmitting waveguide module 41, a receiving waveguide module 44 used in conjunction with the transmitting waveguide module 41, and one or more photoelectric detection modules used in conjunction with the receiving waveguide module 44.

[0148] The transmitting waveguide modules 41 of different signal processing channels can be the same or different, and the receiving waveguide modules 44 of different signal processing channels can be the same or different. Each signal processing channel can work independently without affecting each other.

[0149] At least two signal processing channels have their transmitting waveguide module 41, where the end emitting the probe light, and the receiving waveguide module 44, where the receiving waveguide module 44 receives the echo light, both located at the same end of the optical chip 4, and can be configured as follows: Figure 34 The coplanar arrangement shown, or, as... Figure 35 The stepped setup is shown.

[0150] When the lidar 3 is working, the working principle of each signal processing channel can be as follows: the detection light is input to the transmitting waveguide module 41 through the first coupler 71 (e.g., end face coupler) from the external optical fiber, and then emitted from the end of the transmitting waveguide module 41; the local oscillator light is input through the second coupler 72 (e.g., end face coupler) from the external optical fiber, and then split into multiple paths by the splitter 73 and sent to the corresponding photoelectric detection module; the echo light is first collected by the receiving waveguide module 44 and then transmitted to the corresponding photoelectric detection module.

[0151] The photoelectric detection module may include a mixer 74 and a balanced photodetector 75. The mixer 74 can be a 180° mixer, such as a 3dB coupler; the mixer 74 can output two beat frequency signals with a phase difference of 180°. The balanced photodetector 75 is used to receive the two beat frequency signals and perform balanced detection on the two beat frequency signals to convert them into electrical signals. Then, the back-end signal processing module processes the signals using a certain algorithm to obtain the distance and velocity information of the target object.

[0152] It should be understood that although the above embodiments are illustrated using a photodetector module including a mixer and a balanced photodetector as an example, this application is not limited to this. As long as it is ensured that it can be used to receive the local oscillator light and the echo light, so that the local oscillator light and the echo light beat, and the beat frequency signal is received and converted into a relevant electrical signal, it is acceptable. For example, in some other embodiments of this application, the photodetector module may also include only a photodetector; the photodetector is used to receive the local oscillator light and the echo light, which can beat in free space, and the photodetector is used to receive the beat frequency signal and convert it into a relevant electrical signal.

[0153] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" means at least two, for example, two, three, four, etc. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0154] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. An optical chip, characterized in that, include: Cladding; A transmitting waveguide module is embedded in the cladding and extends along a first direction. The transmitting waveguide module is used to transmit probe light and output it to the outside of the optical chip. The first direction is a direction perpendicular to the thickness direction of the optical chip. as well as A receiving waveguide module, embedded in the cladding, is used to receive the echo light reflected back by the target object from the probe light. The end of the transmitting waveguide module that emits the probe light and the end of the receiving waveguide module that receives the echo light are located at the same end of the optical chip. When viewed along the thickness direction, the transmitting waveguide module and the receiving waveguide module are arranged opposite each other along a second direction, and any two of the second direction, the first direction, and the thickness direction are perpendicular to each other. Wherein, the distance between the transmitting waveguide module and the receiving waveguide module is less than or equal to twice the mode length of the echo light; The transmitting waveguide module has a first coupling region, and the receiving waveguide module has a second coupling region. When viewed along the thickness direction, the first coupling region and the second coupling region are arranged opposite to each other along the second direction. The second coupling region bends towards the transmitting waveguide module relative to the adjacent portion upstream of the second coupling region in the receiving waveguide module, so that the first coupling region and the second coupling region are configured to couple the optical signal transmitted by the transmitting waveguide module into the receiving waveguide module.

2. The optical chip according to claim 1, characterized in that, The coupling ratio between the transmitting waveguide module and the receiving waveguide module is α, and the optical chip satisfies: 0.1%≤α≤1%.

3. The optical chip according to claim 1, characterized in that, The extension direction of the second coupling region is a curve, or the extension direction of the second coupling region is a combination of a curve and a straight line.

4. The optical chip according to claim 1, characterized in that, The receiving waveguide module includes at least two receiving waveguides, each receiving waveguide having a first end and a second end disposed opposite to each other, the first end being used to receive the echo light, and each receiving waveguide being spaced apart along the second direction; The receiving waveguide adjacent to the transmitting waveguide module is the first receiving waveguide, and the first receiving waveguide is provided with the second coupling region.

5. The optical chip according to claim 4, characterized in that, The receiving waveguide module includes: At least three receiving waveguides; and At least one beam combiner, the beam combiner including two input terminals and one output terminal, the at least one beam combiner including at least one first beam combiner, each of the input terminals of the first beam combiner being connected to the receiving waveguide other than the first receiving waveguide, and the output terminal of the beam combiner being connected to the first transmission waveguide.

6. The optical chip according to claim 5, characterized in that, The receiving waveguide module includes at least four receiving waveguides; The at least one bundle combiner includes a first bundle combiner and at least one second bundle combiner connected in series. One input terminal of the second beam combiner is connected to the output terminal of the upstream beam combiner through the first transmission waveguide, and the other input terminal is connected to a receiving waveguide. The receiving waveguides connected to adjacent beam combiners are adjacent to each other.

7. The optical chip according to claim 4, characterized in that, The receiving waveguide module includes at least one beam combiner, which includes two input terminals and one output terminal. The at least one beam combiner includes a first beam combiner, one input of which is connected to the first receiving waveguide, and the other input of which is connected to the receiving waveguide adjacent to the first receiving waveguide. The output of each beam combiner is connected to a first transmission waveguide.

8. The optical chip according to claim 7, characterized in that, The receiving waveguide module includes at least three receiving waveguides, and the at least one beam combiner includes at least one second beam combiner, wherein the first beam combiner and the at least one second beam combiner are connected in series. One input terminal of the second beam combiner is connected to the upstream beam combiner via the first transmission waveguide, and the other input terminal of the second beam combiner is connected to a receiving waveguide. The receiving waveguides connected to the input terminals of each beam combiner are different. Except for the first receiving waveguide, the receiving waveguides connected to adjacent beam combiners are adjacent.

9. The optical chip according to claim 1, characterized in that, The receiving waveguide module includes: At least two receiving waveguides, each receiving waveguide including a first end and a second end disposed opposite to each other, the first end being used to receive the echo light, the receiving waveguides being spaced apart along the second direction, and the receiving waveguide adjacent to the transmitting waveguide module being the first receiving waveguide; and At least one beam combiner, the beam combiner including two input terminals and one output terminal, the at least one beam combiner including a first beam combiner, one input terminal of the first beam combiner being connected to the first receiving waveguide, the other input terminal being connected to the receiving waveguide adjacent to the first receiving waveguide, and the output terminal of the first beam combiner being connected to a first transmission waveguide. The first transmission waveguide connected to the output end of the first beam combiner is provided with the second coupling region.

10. The optical chip according to claim 1, characterized in that, The receiving waveguide module includes: At least three receiving waveguides, each receiving waveguide including a first end and a second end disposed opposite to each other, the first end being used to receive the echo light, the receiving waveguides being spaced apart along the second direction, and the receiving waveguide adjacent to the transmitting waveguide module being the first receiving waveguide; and At least two beam combiners are provided, each beam combiner having two input terminals and one output terminal. The at least two beam combiners include a first beam combiner and at least one second beam combiner connected in series. One input terminal of the first beam combiner is connected to a first receiving waveguide, and the other input terminal is connected to a receiving waveguide adjacent to the first receiving waveguide. The output terminal of the first beam combiner is connected to a first transmission waveguide. One input terminal of the second beam combiner is connected to the upstream beam combiner through the first transmission waveguide, and the other input terminal is connected to a receiving waveguide. The receiving waveguides connected to the input terminals of each beam combiner are different. Except for the first receiving waveguide, the receiving waveguides connected to adjacent beam combiners are adjacent. The first transmission waveguide connected to the output end of the first beam combiner is provided with the second coupling region, and / or the first transmission waveguide connected to the output end of the second beam combiner is provided with the second coupling region.

11. The optical chip according to claim 6, 8, or 10, characterized in that, Between two adjacent combiners, the receiving waveguide connected to the downstream combiner is farther away from the transmitting waveguide module than the receiving waveguide connected to the upstream combiner.

12. The optical chip according to claim 1, characterized in that, The first coupling region is bent toward the receiving waveguide module relative to other parts of the transmitting waveguide module adjacent to the first coupling region, so that the first coupling region and the second coupling region are configured to allow the optical signal transmitted by the transmitting waveguide module to be coupled into the receiving waveguide module.

13. The optical chip according to claim 1, characterized in that, The transmitting waveguide module includes at least two transmitting waveguides, each of which is spaced apart along the second direction. The at least two transmitting waveguides include: A first transmitting waveguide has an input end and an output end disposed opposite to each other, the input end being used to receive the probe light; and At least one second transmitting waveguide, viewed along the thickness direction, is disposed opposite to the first transmitting waveguide along the second direction. The first transmitting waveguide and the second transmitting waveguide are configured to allow probe light in the first transmitting waveguide to couple into the second transmitting waveguide, so that the transmitting waveguide module outputs the probe light via at least two of the transmitting waveguides.

14. The optical chip according to claim 13, characterized in that, The first transmitting waveguide includes a first coupling portion, and the second transmitting waveguide includes a second coupling portion. When viewed along the thickness direction, the first coupling portion and the second coupling portion are disposed opposite to each other along the second direction. The first coupling portion and the second coupling portion are configured to allow the probe light in the first coupling portion to couple into the second coupling portion. Along the first direction, the cross-sectional profile of the first coupling portion gradually contracts; Along the first direction, the cross-sectional profile of the second coupling portion remains constant.

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