Laser radar

Abstract

The invention provides a laser radar, and relates to the technical field of laser radars. The laser radar comprises a laser unit configured to emit first signal laser and second signal laser, the first signal laser has an up-band, the second signal laser has a down-band, the wavelength of the first signal laser is different from that of the second signal laser, and the wavelength of the second signal laser is different from that of the up-band. Or the polarization direction of the first signal laser is different from that of the second signal laser; the angle scanning compensator is configured to receive the first signal laser and the second signal laser in a time-sharing mode and emit the first signal laser and the second signal laser in the basically same direction.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and more specifically, to a lidar system. Background Technology

[0002] LiDAR (Light Detection and Ranging) is a radar system that uses emitted laser beams to detect the position, velocity, and other characteristics of targets. Its working principle involves emitting a detection signal towards the target, then comparing the received signal reflected back from the target with the emitted signal. After appropriate processing, information about the target can be obtained, such as its distance, azimuth, altitude, velocity, attitude, and even shape. This allows for the detection, tracking, and identification of targets such as aircraft and missiles. LiDAR is now widely deployed in various scenarios, including autonomous vehicles. While scanning a scene, LiDAR can actively estimate the distance and velocity of environmental features and generate a point position cloud indicating the three-dimensional shape of the environment. Summary of the Invention

[0003] Embodiments of this application provide a lidar. The lidar includes: at least one laser transmission detection channel, wherein each of the at least one laser transmission detection channel includes: a laser unit configured to emit a first signal laser and / or emit a second signal laser, the first signal laser and the second signal laser being frequency-modulated lasers, the first signal laser having a frequency-up band and the second signal laser having a frequency-down band, wherein the wavelength of the first signal laser is different from the wavelength of the second signal laser, or the polarization direction of the first signal laser is different from the polarization direction of the second signal laser; a light emitter configured to emit the first signal laser and / or the second signal laser; an angle scanning compensator configured to receive the first signal laser and the second signal laser from the light emitter in a time-division multiplexing manner, and to emit the first signal laser and the second signal laser along substantially the same direction, wherein the first signal laser and the second signal laser reflect upon encountering a target object to generate a first reflected laser and a second reflected laser; a detection component configured to receive the first reflected laser and the second reflected laser, obtain a beat frequency signal of the first reflected laser and the second reflected laser, and output the beat frequency signal; and an acquisition and processing device configured to determine the speed and / or distance of the target object based on the beat frequency signal.

[0004] Optionally, the angle scanning compensator includes a dispersive device, wherein the wavelength of the first signal laser is different from the wavelength of the second signal laser; or the angle scanning compensator includes a birefringent device, wherein the polarization direction of the first signal laser is different from the polarization direction of the second signal laser.

[0005] Optionally, the angle scanning compensator includes a rotating mirror, wherein the dispersive device or the birefringent device directs the first signal laser and the second signal laser onto the rotating mirror with a first angular deviation, and the rotating mirror emits the first signal laser and the second signal laser in substantially the same direction; or the rotating mirror directs the first signal laser and the second signal laser onto the dispersive device or the birefringent device with a first angular deviation, and the dispersive device or the birefringent device emits the first signal laser and the second signal laser in substantially the same direction.

[0006] Optionally, the light emitter includes a first polarization rotating beam splitter or circulator.

[0007] Optionally, the laser unit includes: a first laser configured to generate a first laser having a first wavelength; and a second laser configured to generate a second laser having a second wavelength.

[0008] Optionally, the laser unit further includes: a first optical switch configured to receive the first laser and selectively allow or cut off the first laser; a second optical switch configured to receive the second laser and selectively allow or cut off the second laser; a first multiplexer connected to the first and second optical switches and configured to multiplex the first and second lasers and output the first and second lasers in a time-division multiplexing manner; or the laser unit further includes: a first beam splitter configured to receive the first and second lasers, split the first laser into a first component and a second component, split the second laser into a first component and a second component, and split the second laser into a first component and a second component; a first phase shifter and a second phase shifter, wherein the first phase shifter is configured to receive the first component and the first component of the first laser and perform phase shifting on the first component and the first component of the second laser, and the second phase shifter is configured to receive the second component and the second component of the first laser and perform phase shifting on the second component and the second component of the second laser, such that the phase-shifted first component and the phase-shifted first component and the second component of the second laser are... The second component of the laser has a phase difference of 0 degrees and the phase difference between the first component of the phase-shifted second laser and the second component of the phase-shifted second laser is 180 degrees, or the phase difference between the first component of the phase-shifted first laser and the second component of the phase-shifted first laser is 180 degrees and the phase difference between the first component of the phase-shifted second laser and the second component of the phase-shifted second laser is 0 degrees; a first combiner is configured to receive the first component of the phase-shifted first laser and the first component of the phase-shifted second laser, and to receive the second component of the phase-shifted first laser and the second component of the phase-shifted second laser, wherein, when the phase difference between the first component of the phase-shifted first laser and the second component of the phase-shifted first laser is 0 degrees and the phase difference between the first component of the phase-shifted first laser and the second component of the phase-shifted second laser is 180 degrees, the first combiner outputs the first laser; when the phase difference between the first component of the phase-shifted first laser and the second component of the phase-shifted first laser is 180 degrees and the phase difference between the first component of the phase-shifted second laser and the second component of the phase-shifted second laser is 0 degrees, the first combiner outputs the second laser.

[0009] Optionally, each of the at least one laser transmission detection channel further includes: a second beam splitter configured to receive the first laser and the second laser in a time-division manner, splitting the first laser into a first signal laser and a first local oscillator laser, and splitting the second laser into a second signal laser and a second local oscillator laser.

[0010] Optionally, the laser unit includes: a first laser configured to generate a first laser having a first wavelength; a third beam splitter configured to receive the first laser and split the first laser into a first laser component and a second laser component; a first phase shifter and a second phase shifter, wherein the first phase shifter is configured to receive the first laser component and perform phase shifting on the first laser component, and the second phase shifter is configured to receive the second laser component and perform phase shifting on the second laser component, such that the phase of the first laser component and the phase of the second laser component differ by 90 degrees or -90 degrees; and a first beam splitter configured to receive the phase-shifted first laser component and the phase-shifted second laser component, and output a first combined laser or a second combined laser, wherein when the phase of the phase-shifted first laser component and the phase of the phase-shifted second laser component differ by 90 degrees, the first beam splitter outputs the first combined laser; and when the phase of the phase of the phase-shifted first laser component and the phase of the phase-shifted second laser component differs by -90 degrees, the first beam splitter outputs the second combined laser.

[0011] Optionally, each of the at least one laser transmission detection channel further includes: a second polarization beam splitter rotator configured to maintain the polarization direction of the first combined laser beam, change the polarization direction of the second combined laser beam, and output the first combined laser beam with unchanged polarization direction and the second combined laser beam with changed polarization direction.

[0012] Optionally, each of the at least one laser transmission detection channel further includes: a fourth beam splitter located at the optical emitting end of the second polarization rotating beam splitter, and configured to split the first combined laser beam into a first signal laser and a first local oscillator laser, or to split the second combined laser beam into a second signal laser and a second local oscillator laser.

[0013] Optionally, the detection component includes: a first mixer configured to receive the reflected laser and the first local oscillator laser, or to receive the reflected laser and the second local oscillator laser, and to mix the reflected laser and the first local oscillator laser, or to mix the reflected laser and the second local oscillator laser; and a balance detector configured to receive the output of the first mixer and to detect the beat frequency during the up-frequency phase and the beat frequency during the down-frequency phase.

[0014] The solution proposed in this application has the following beneficial effects:

[0015] By incorporating an angle scanning compensator, the solution presented in this application resolves the angle mismatch problem caused by mirror rotation, ensuring that the emitted laser beams are emitted in essentially the same direction. This solution eliminates the need for multiple detection components, thereby reducing the number of devices, minimizing their footprint, and consequently reducing system size and cost. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] Figure 1 The waveforms of the transmitted and received beams using the relevant FWCW frequency sweeping method in the related technology are shown.

[0018] Figure 2A This is a schematic diagram illustrating the angular mismatch between the rotating mirror of a related lidar and the emitted beam.

[0019] Figure 2B This is a schematic diagram illustrating the compensation for angular mismatch of the emitted beam in the lidar disclosed herein.

[0020] Figures 3A-3F This is a schematic diagram of the structure of the lidar provided in this disclosure;

[0021] Figure 4A and Figure 4B A waveform diagram of the detection signal of the lidar provided in this disclosure;

[0022] Figure 5A and Figure 5B A schematic diagram of an autonomous vehicle including the lidar of this application is shown. Detailed Implementation

[0023] The term "and / or" used in this article is merely a description of 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. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0024] It should be understood that although the terms first, second, third, etc., may be used to describe different objects in the embodiments of this application, these objects should not be limited to these terms. These terms are only used to distinguish these objects. For example, without departing from the scope of the embodiments of this application, first may also be referred to as second, and similarly, second may also be referred to as first.

[0025] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the article or device that includes said element.

[0026] The relevant FMCW (Frequency-Modulated Continuous Wave) lidar mainly transmits and receives continuous laser beams, interferes the reflected light and the local oscillator light, and uses frequency mixing detection technology to measure the frequency difference between transmission and reception, and then calculates the distance to the target object through the frequency difference.

[0027] Figure 1 A schematic diagram illustrating the principle of measuring moving objects using a correlated triangular wave linear frequency modulated continuous wave (FMCW) lidar is shown. Figure 1 In the diagram, the solid-lined triangular wave represents the instantaneous time-frequency relationship of the signal beam or local oscillator beam of the lidar, while the dashed-lined triangular wave represents the reflected beam of a target moving towards the lidar. Here, τ is the delay of the reflected beam, f1 and f2 are the beat frequencies of the reflected beam in the upper and lower frequency sweep sections (i.e., the beat frequencies in the rising and falling frequency bands between the reflected beam and the local oscillator beam), respectively, and T is one period of the upper and lower frequency sweeps. B It is the sweep bandwidth of linear frequency modulation, f d = (f2-f1) / 2. Figure 1 In the above, the beat frequencies of the rising and falling frequency bands of the reflected beam are respectively:

[0028]

[0029] The distance R and velocity ν of the target are shown below:

[0030]

[0031] FMCW lidar boasts significant technological advantages, but its practical application presents the following challenges: The lidar involves a rotating mirror. The transmitter emits laser light towards the mirror, which reflects it back to the object being measured. The object then reflects the laser back to the mirror, which in turn reflects it to the receiver. During this process, the continuous rotation of the mirror can cause adjacent up-frequency and down-frequency signals to illuminate different objects or different parts of the same object. Figure 2AThe solid and dashed lines in the diagram illustrate this. Because different objects being detected, or different parts of the same object, have varying distances from the lidar (e.g., ...), the distance between the lidar and the target object varies (e.g., ...). Figure 2A The distance and velocity of the target object are calculated using formulas 1 and 2 (D1 and D2 in the formulas), so errors will occur when using these formulas to calculate the distance and velocity of the target object. This error is also called the angle mismatch of the rotating mirror. This angle mismatch will affect the accuracy of the lidar measurement.

[0032] To solve this technical problem, one approach is to simultaneously transmit the signal beam during the up-frequency phase and the signal beam during the down-frequency phase. However, this approach has the disadvantage of requiring two detection systems, which increases equipment cost and size.

[0033] To address the aforementioned technical problems, this application provides a lidar that generates a constant angle compensation for the signal beams in adjacent up-frequency and down-frequency phases, thereby solving the angle mismatch problem mentioned above. Figure 2B As shown. Furthermore, the lidar of this application uses only one detection system, which does not increase the cost and size of the equipment.

[0034] The specific embodiments of this application are described in detail below with reference to the accompanying drawings.

[0035] Figure 3A Schematic diagram of the structure of the lidar provided in some embodiments of this application Figure 1 .like Figure 3A As shown, the lidar includes at least one laser transmission detection channel. Although Figure 3A Only one laser transmission detection channel is shown in the diagram. Those skilled in the art will understand that a lidar may include two or more laser transmission detection channels arranged in parallel. Each laser transmission detection channel can perform measurement work independently or collaboratively, and the detection laser emitted by each channel corresponds to a different position of the target object.

[0036] Any laser transmission and detection channel may include a laser unit 30. The laser unit 30 is configured to transmit a first signal laser and a second signal laser in a time-division multiplexing manner. The first and second signal lasers are FMCW frequency-modulated lasers. The first signal laser has a frequency-up section, and the second signal laser has a frequency-down section. The wavelength of the first signal laser is λ1, and the wavelength of the second signal laser is λ2. The wavelength of the first signal laser is different from the wavelength of the second signal laser (i.e., λ1 ≠ λ2). One frequency-up section of the first signal laser and one frequency-down section of the adjacent second signal laser can form a sweep cycle of a triangular wave. This sweep cycle is T, such as... Figure 4A As shown. Figure 4A The diagram shows that the first signal laser is located in the up-frequency band, and the second signal laser is located in the down-frequency band.

[0037] Specifically, the laser unit 30 may include a first laser source 301 and a second laser source 302. The first laser source 301 emits a modulated first laser with a wavelength of λ1, and the second laser source 302 emits a modulated second laser with a wavelength of λ2. Both the first and second lasers may have triangular waveforms, which can be as follows: Figure 4A The waveform shown is illustrated. Either the first laser source 301 or the second laser source 302 can be, for example, a solid-state laser, a semiconductor laser, etc., specifically a distributed feedback laser (DFB), a vertical-cavity surface-emitting laser (VCSEL), an external cavity laser, etc. Each of the first laser source 301 and the second laser source 302 may include a modulator that receives a modulation signal. The modulator can be configured to modulate the beam based on the modulation signal, such that each of the first laser source 301 and the second laser source 302 generates and outputs a swept-frequency beam, i.e., a beam whose frequency varies within a predetermined range. The frequency of the laser beam output by the first laser source 301 and the second laser source 302 when unmodulated is substantially constant, referred to as the frequency of the unmodulated beam. The first laser source 301 and the second laser source 302 can achieve the output of a swept-frequency beam after modulation. The first laser source 301 and the second laser source 302 can also be, for example, an external light source, which is introduced into the laser transmission and detection channel through an optical path (e.g., an optical fiber). The first laser can have a frequency-up section, and the second laser can have a frequency-down section. The wavelength of the first laser is λ1, and the wavelength of the second laser is λ2. The wavelength of the first laser is different from the wavelength of the second laser (i.e., λ1 ≠ λ2). One frequency-up section of the first laser and one frequency-down section of the second laser can form one sweep cycle of a triangular wave waveform.

[0038] Optionally, the laser unit 30 may further include a 2×1 optical switch. This 2×1 optical switch may be an integrated optical switch or an on-chip optical switch. The 2×1 optical switch is configured to selectively output either a first laser or a second laser in a time-division multiplexing manner. In some cases, the 2×1 optical switch may output a first laser with a gradually increasing frequency in the first half of a sweep cycle T, and a second laser with a gradually decreasing frequency in the second half of the sweep cycle T; or conversely, the 2×1 optical switch may output a second laser with a gradually increasing frequency in the first half of a sweep cycle T, and a first laser with a gradually decreasing frequency in the second half of the sweep cycle T.

[0039] Specifically, the 2×1 optical switcher may include a first beam splitter 303, a first phase shifter 304, a second phase shifter 305, and a first combiner 306. The first beam splitter 303 is configured to receive a first laser and a second laser, split the first laser into a first component and a second component, and split the second laser into a first component and a second component. The first beam splitter 303 includes two input ports and two output ports. The first beam splitter 303 receives the first laser and the second laser from the two input ports respectively, and outputs the first component and the first component of the first laser from the first output port, and outputs the second component and the second component of the first laser from the second output port. The first component and the second component of the first laser may have the same waveform and wavelength as the first laser, and the first component and the second component of the second laser may have the same waveform and wavelength as the second laser.

[0040] The first phase shifter 304 is configured to receive the first component of the first laser and the first component of the second laser, and to perform phase shifting on the first component of the first laser and the first component of the second laser; the second phase shifter 305 is configured to receive the second component of the first laser and the second component of the second laser, and to perform phase shifting on the second component of the first laser and the second component of the second laser. Through the first phase shifter 304 and the second phase shifter 305, the phases of the first component of the first laser, the second component of the first laser, the first component of the second laser, and the second component of the second laser can be changed, such that in a first case, the phase difference between the first component of the first laser and the second component of the first laser is 0 degrees, and the phase difference between the first component of the second laser and the second component of the second laser is 180 degrees; or in a second case, the phase difference between the first component of the first laser and the second component of the first laser is 180 degrees, and the phase difference between the first component of the second laser and the second component of the second laser is 0 degrees.

[0041] In some embodiments, the first phase shifter 304 and the second phase shifter 305 can jointly adjust the phase of the first component of the first laser, the second component of the first laser, the first component of the second laser, and the second component of the second laser under the control of a controller inside or outside the laser unit 30.

[0042] In some embodiments, the first combiner 306 has two input terminals and one output terminal, and is configured to receive a first component of a phase-shifted first laser and a first component of a second laser and / or receive a second component of a phase-shifted first laser and a second component of a second laser. Specifically, when the phase difference between the first component of the first laser and the second component of the first laser is 0 degrees and the phase difference between the first component of the second laser and the second component of the second laser is 180 degrees, the output terminal of the first combiner 306 outputs the first laser; when the phase difference between the first component of the first laser and the second component of the first laser is 180 degrees and the phase difference between the first component of the second laser and the second component of the second laser is 0 degrees, the output terminal of the first combiner 306 outputs the second laser.

[0043] In this embodiment, the first phase shifter 304 and the second phase shifter 305 can shift the phases of the first components of the first and second lasers of the first laser, so that the first and second components of the first laser entering the first combiner 306 are 180 degrees out of phase, thus being out of phase and canceling each other out. In another embodiment, the first phase shifter 304 and the second phase shifter 305 can shift the phases of the first and second components of the second laser, so that the first and second components of the second laser entering the first combiner 306 are 180 degrees out of phase, thus being out of phase and canceling each other out. Therefore, by controlling the first phase shifter 304 and the second phase shifter 305 to shift the phases of the first and second components of the first laser, the first and second components of the first laser, and the first and second components of the second laser, the first combiner 306 can selectively output either the first or second laser. Thus, the 2×1 optical switcher realizes the output switching between the first and second lasers.

[0044] Optionally, the laser unit 30 further includes a second beam splitter 307, located at the optical output end of the 2×1 optical switch. The second beam splitter 307 is configured to receive either the first laser or the second laser output from the 2×1 optical switch in a time-division manner, and to split the first laser into a first local oscillator laser and a first signal laser, or the second laser into a second local oscillator laser and a second signal laser. The first local oscillator laser, the first signal laser, and the first laser have the same wavelength, the same sweep period, and the same phase. The second local oscillator laser, the second signal laser, and the second laser have the same wavelength, the same sweep period, and the same phase.

[0045] Optionally, each laser transmission detection channel may further include a first polarization rotating beamsplitter 308. The first polarization rotating beamsplitter 308 may be a single PSR (Polarization Splitting Rotator) or a polarization splitter (PS) and a polarization rotator connected together. The first polarization rotating beamsplitter 308 is configured to receive the first signal laser and the second signal laser in a time-division multiplexing manner, and to receive reflected laser light. Specifically, the first polarization rotating beamsplitter 308 may be configured to receive the first signal laser or the second signal laser from a first port, emit the first signal laser or the second signal laser from a second port, receive reflected laser light from the second port, and transmit the reflected laser light from the second port to a third port. The reflected laser light may be the reflected laser light generated after the detection laser of the lidar illuminates the target object.

[0046] Optionally, each laser transmission detection channel may further include an angle scan compensator 312. The angle scan compensator 312 is configured to receive the first signal laser and the second signal laser in a time-division manner, and to emit the first signal laser and the second signal laser in substantially the same direction in a time-division manner. Specifically, the angle scan compensator 312 includes a dispersive device 3122 and a rotating mirror 3121. For example... Figure 3A As shown, the dispersive device 3122 is configured to receive the first and second signal lasers in a time-division multiplexing manner. Since the wavelengths of the first and second signal lasers are different, when they are incident on the dispersive device 3122 at the same incident angle, their exit angles are different. Due to the rotation of the rotating mirror 3121, if the first and second signal lasers are incident on the rotating mirror 3121 at the same incident angle, the mirror will emit them at different angles, causing them to irradiate different target objects or different parts of the same target object. This results in an angle mismatch problem when calculating the speed and distance of the target object using reflected light. By setting the dispersive device 3122, the angular deviation caused by the rotation of the rotating mirror can be compensated, ensuring that the exit directions of the first and second laser signals output by the angle scanning compensator 312 are basically the same, thus solving the angle mismatch problem.

[0047] The dispersive device 3122 can be configured to produce different emission angles for the first and second signal lasers. Specifically, one or more of the material, thickness, and refractive index of the dispersive device 3122 can be configured or selected to ensure that the first and second signal lasers exit the dispersive device 3122 at different angles. For example, the dispersive device 3122 can be a grating, a prism, or a wedge. The angle and material of the grating, prism, or wedge can be selected to allow the dispersive device 3122 to deflect the first signal laser with wavelength λ1 by a first angle α and the second signal laser with wavelength λ2 by a second angle β, where the angle difference |α-β| can be a preset value. This preset value can be selected based on the rotational speed of the rotating mirror 3121 and the sweep period T of the lidar, so that the emission directions of the first and second signal lasers emitted by the angle scanning compensator 312 are basically the same, such as... Figure 2B As shown. In some embodiments, the emission direction of the first signal laser emitted by the angle scanning compensator 312 may have an angle of 0-5 degrees with respect to the emission direction of the second signal laser, such as an angle of 0, 1, 2, 3, 4, or 5 degrees. In other embodiments, the emission direction of the first signal laser emitted by the angle scanning compensator 312 may have an angle of 0-10 degrees with respect to the emission direction of the second signal laser, such as an angle of 0-6, 0-7, 0-8, 2-5, 3-6, or 1-7 degrees. This application is not limited thereto.

[0048] When the first and second signal lasers illuminate the target object, reflected laser light is generated. Since the emission directions of the first and second signal lasers are essentially the same, the reflection directions of the reflected lasers are also essentially the same. The reflected laser light can include the reflected laser light from the first signal laser and / or the reflected laser light from the second signal laser. The reflected laser light from the first and second signal lasers is received by the optical receiver of the lidar at different times. The lidar's optical receiver can transmit the reflected laser light to the second port of the first polarization rotating beam splitter 308, and the first polarization rotating beam splitter 308 transmits the reflected laser light to the third port.

[0049] Optionally, each laser transmission detection channel also includes a detection component 33. The detection component 33 is configured to receive reflected laser light from the third port of the first polarization rotating beam splitter 308. The reflected laser light can be a reflected beam with a period of T. (Reference) Figure 1 and Figure 3A The up-frequency band of the reflected laser can be a first reflected laser with a wavelength similar to or close to λ1, and the down-frequency band can be a second reflected laser with a wavelength similar to or close to λ2. Specifically, the detection component 33 can receive the first reflected laser with a wavelength similar to or close to λ1 and the second reflected laser with a wavelength similar to or close to λ2, as well as the first local oscillator laser and the second local oscillator laser in a time-division multiplexing manner.

[0050] Specifically, the detection component may include a mixer 309 configured to receive a first local oscillator laser and a first reflected laser in a time-division multiplexing manner, and to receive a second local oscillator laser and a second reflected laser, thereby causing optical interference between the first local oscillator laser and the first reflected laser, and optical interference between the second local oscillator laser and the second reflected laser, to generate a coherent signal. Optionally, the mixing device may be a coupler, such as a 2×2 coupler.

[0051] Optionally, the detection component 33 may further include a balance detector 310, which may be configured to receive the output signal of the mixer 309, detect the beat frequency between the first local oscillator laser and the first reflected laser, and the beat frequency between the second local oscillator laser and the second reflected laser, based on the output signal, and output the detection result. The balance detector 310 may include one or more photodetectors.

[0052] Optionally, the lidar of this application may further include an acquisition and processing device 311. The acquisition and processing device 311 is configured to receive the output of the balanced detector 310, determine the beat frequency signal based on the output, and obtain the distance and / or velocity information of the target object through calculation.

[0053] Couplers, mixers 309, balanced detectors 310, photodetectors, and acquisition and processing devices 311 are common components in the field of FMCW lidar, and will not be described in detail here. The acquisition and processing device 311 includes, for example, a collector and a processor. The collector can convert the detection information, which is an analog signal, into a digital signal, such as an analog-to-digital converter. The processor processes the digital signal to determine the distance and velocity of the lidar relative to the target object. The processor can be, for example, a field-programmable gate array (FPGA) or a digital signal processor (DSP).

[0054] In some embodiments, such as Figure 3A As shown, the lidar further includes a lens assembly 313. The lens assembly 313 is disposed between the first polarization rotating beam splitter 308 and the angle scanning compensator 312, and is configured to collimate the laser output from the first polarization rotating beam splitter 308, and to focus the reflected laser to couple it into the first polarization rotating beam splitter 308.

[0055] In some embodiments, the lidar further includes a beam scanning guide device disposed between the lens assembly 313 and the target object to achieve light deflection and scanning. The beam scanning guide device may be disposed between the angle scanning compensator 312 and the target object, or it may be disposed between the lens assembly 312 and the angle scanning compensator 312.

[0056] The lidar disclosed herein can perform angle compensation on the laser emitted by the rotating mirror, thereby avoiding the angle mismatch caused by the two consecutive up-frequency stage signals and down-frequency stage signals during the rotation of the mirror, which can improve the measurement accuracy of the lidar. In addition, the solution of this application only requires one detection component, thereby saving the number of components and reducing the space occupied by the components.

[0057] Figure 3B This is another structural schematic diagram of the lidar of this application. Figure 3B The structure of the lidar shown is similar to Figure 3A The lidar shown has a similar structure. The difference lies in... Figure 3B In this embodiment, the structure of the angle scanning compensator 312 in the lidar differs from that of the other embodiments. Figure 3A The structure of the angle scanning compensator 312 in the lidar is shown. Specifically, the angle scanning compensator 312 includes a dispersive device 3122 and a rotating mirror 3121, as shown in the figure. Figure 3B As shown, the rotating mirror 3121 is configured to receive the first and second signal lasers from the first polarization rotating beam splitter 308 in a time-division manner, and then project the first and second signal lasers onto the dispersive device 3122. The dispersive device 3122 is configured to receive the first and second signal lasers in a time-division manner. Due to the rotation of the rotating mirror 3121, there is an angular difference between the first and second signal lasers projected onto the dispersive device 3122. Since the wavelengths of the first and second signal lasers are different, when the first and second signal lasers are incident on the dispersive device 3122 in a time-division manner with the above-mentioned incident angle difference, by configuring the dispersive device 3122, the exit angles of the first and second signal lasers can be made the same, thereby overcoming the above-mentioned angle mismatch problem. Figure 3B The working principle of the other devices shown is the same as Figure 3A The corresponding devices shown operate on similar principles; for details, please refer to the above. Figure 3A The relevant descriptions in [the document] are omitted here to avoid duplication.

[0058] Figure 3C This is schematic diagram three of the lidar structure described in this application. Figure 3CAs shown, any laser transmission and detection channel of the lidar can include a laser unit 30. The laser unit 30 is configured to transmit a first signal laser and a second signal laser in a time-division multiplexing manner. Both the first and second signal lasers are FMCW frequency-modulated lasers. The first signal laser has a frequency-upgrading band, and the second signal laser has a frequency-downgrading band. The wavelength of the first signal laser is λ1, and the wavelength of the second signal laser is λ2. The wavelength of the first signal laser is different from the wavelength of the second signal laser. One frequency-upgrading band of the first signal laser and one frequency-downgrading band of the adjacent second signal laser can form a sweep frequency period of a triangular wave. This sweep frequency period is T.

[0059] Specifically, the laser unit 30 may include a first laser source 301 and a second laser source 302. The first laser source 301 emits a modulated first laser beam with a wavelength of λ1, and the second laser source 302 emits a modulated second laser beam with a wavelength of λ2. The first and second laser beams may have the same waveform. Either the first laser source 302 or the second laser source 302 may be compatible with... Figure 3A and Figure 3B The first laser source 302 and the second laser source 302 shown have the same function, and related information can be found above. Figure 3A The description of Figure B is not detailed here.

[0060] Optionally, the laser unit 30 may further include a first optical shutter 313, a second optical shutter 314, and a first multiplexer / combiner 315. The first optical shutter 313 is located at the light output end of the first light source 301 and is configured to allow the first laser to pass through or not pass through (i.e., cut off). The second optical shutter 314 is located at the light output end of the second light source 302 and is configured to allow the second laser to pass through or not pass through (i.e., cut off). The first optical shutter 313 and the second optical shutter 314 can control the passage or obstruction of the laser under the control of an external controller. The external controller may be a controller known to those skilled in the art, and will not be described in detail here to avoid repetition. The first multiplexer / combiner 315 is disposed at the output end of the first optical shutter 313 and the second optical shutter 314 and is configured to receive the first laser or the second laser from the first optical shutter 313 and the second optical shutter 314, and output the first laser or the second laser in a time-division multiplexing manner. For example, the first multiplexer / combiner 315 can output a first laser with a gradually increasing frequency in the first half of a sweep cycle T, and a second laser with a gradually decreasing frequency in the second half of the sweep cycle T; or conversely, it can output a second laser with a gradually increasing frequency in the first half of a sweep cycle T, and a first laser with a gradually decreasing frequency in the second half of the sweep cycle T. The first multiplexer / combiner 315 outputs either the first laser or the second laser to the second beam splitter 307. Figure 3C The working principle of the other devices shown is the same as Figure 3A The corresponding devices shown operate on similar principles; for details, please refer to the above. Figure 3A The relevant descriptions in [the document] are omitted here to avoid duplication.

[0061] Figure 3D This is a schematic diagram of the lidar structure of this application. Figure 3D The structure of the lidar shown is similar to Figure 3C The lidar shown has a similar structure. The difference lies in... Figure 3D In this embodiment, the structure of the angle scanning compensator 312 in the lidar differs from that of the other embodiments. Figure 3C The structure of the angle scanning compensator 312 in the lidar is shown. Specifically, the angle scanning compensator 312 includes a dispersive device 3122 and a rotating mirror 3121, as shown in the figure. Figure 3D As shown, the rotating mirror 3121 is configured to receive the first signal laser and the second signal laser from the first polarization rotating beam splitter 308 in a time-division manner, and then project the first signal laser and the second signal laser onto the dispersive device 3122. The dispersive device 3122 is configured to receive the first signal laser and the second signal laser in a time-division manner. Due to the rotation of the rotating mirror, there is an angular difference between the first signal laser and the second signal laser projected by the rotating mirror 3121 onto the dispersive device 3122. Since the wavelengths of the first signal laser and the second signal laser are different, when the first signal laser and the second signal laser are incident on the dispersive device 3122 in a time-division manner with the above-mentioned incident angle difference, the dispersive device 3122 can make the exit angles of the first signal laser and the second signal laser the same, thereby overcoming the above-mentioned angle mismatch problem. Figure 3D The working principle of the other devices shown is the same as Figure 3B and Figure 3C The corresponding devices shown operate on similar principles; for details, please refer to the above. Figure 3B and 3C The relevant descriptions in [the document] are omitted here to avoid duplication.

[0062] Figure 3E Five are schematic diagrams illustrating the structure of a lidar provided in some embodiments of this application. Figure 3E As shown, the lidar includes at least one laser transmission detection channel. Although Figure 3E Only one laser transmission detection channel is shown in the figure. Those skilled in the art will understand that a lidar may include two or more laser transmission detection channels arranged in parallel. Each laser transmission detection channel can perform measurement work independently or in cooperation, and the detection laser emitted by each channel corresponds to a different position of the target object.

[0063] Any laser transmission and detection channel may include a laser unit 30, configured to emit a first laser and a second laser in a time-division multiplexing manner. The first and second lasers are FMCW frequency-modulated lasers. The first laser has a frequency-up section, and the second laser has a frequency-down section. The first laser can be transverse electromagnetic wave (TE) mode light, and the second laser can be transverse magnetic wave (TM) mode light; or conversely, the second laser can be transverse electromagnetic wave (TE) mode light, and the first laser can be transverse magnetic wave (TM) mode light. A frequency-up section of the first laser and an adjacent frequency-down section of the second laser can form a sweep cycle of a triangular wave waveform. This sweep cycle is T.

[0064] Specifically, the laser unit 30 may include a first laser source 301, which can emit a modulated first laser beam. The structure and working principle of the first laser source 301 are similar to those of... Figures 3A to 3D The first laser source 301 shown is the same as described above; for details, please refer to the description of the first laser source 301. In some embodiments, the first laser output by the first laser source 301 can be TE mode light or TM mode light. The first laser source 301 is, for example, a solid-state laser, a semiconductor laser, etc., specifically a distributed feedback laser (DFB), a vertical-cavity surface-emitting laser (VCSEL), an external cavity laser, etc. The first laser source 301 may include a modulator that receives a modulation signal. The modulator can be configured to modulate the beam based on the modulation signal, so that the first laser source 301 generates and outputs a swept-frequency beam, i.e., a beam whose frequency varies within a predetermined range. The frequency of the laser beam output by the first laser source 301 when it is not modulated is substantially constant, referred to as the frequency of the unmodulated beam. The first laser source 301 can achieve the output of a swept-frequency beam after modulation. The first laser source 301 can also be, for example, an external light source, which is introduced into the laser transmission and detection channel through an optical path (e.g., an optical fiber).

[0065] Optionally, the laser unit 30 may further include a 1×2 optical switch. This 1×2 optical switch may be an integrated optical switch or an on-chip optical switch. The 1×2 optical switch is configured to selectively output a first combined laser beam or a second combined laser beam in a time-division multiplexing manner. In some cases, the 1×2 optical switch may output a first combined laser beam with a gradually increasing frequency in the first half of a sweep cycle T, and a second combined laser beam with a gradually decreasing frequency in the second half of the sweep cycle T; or conversely, the 1×2 optical switch may output a second combined laser beam with a gradually increasing frequency in the first half of a sweep cycle T, and a first combined laser beam with a gradually decreasing frequency in the second half of the sweep cycle T.

[0066] Specifically, the 1×2 optical switcher may include a third beam splitter 319, a first phase shifter 304, a second phase shifter 305, and a first beam splitter 303. The third beam splitter 319 is configured to receive a first laser beam and split it into a first laser component and a second laser component. The first laser component and the second laser component have the same period, the same waveform, and the same wavelength as the first laser beam. The first laser component and the second laser component also have the same polarization direction, for example, both are TE light or both are TM light.

[0067] The first phase shifter 304 is configured to receive a first laser component, shift the phase of the first laser component, and output the phase-shifted first laser component. The second phase shifter 305 is configured to receive a second laser component, shift the phase of the second laser component, and output the phase-shifted second laser component. Specifically, the phase of the first laser component can be shifted by a first phase, and the phase of the second laser component can be shifted by a second phase. The first phase and the second phase differ by 90 degrees or -90 degrees. Optionally, under the control of a controller located inside or outside the laser unit 30, the first phase shifter 304 can shift the phase of the first laser component, and the second phase shifter 305 can shift the phase of the second laser component, so that the first laser component and the second laser component can differ by 90 degrees or -90 degrees.

[0068] The first beam splitter 303 is configured to receive a phase-shifted first laser component and a phase-shifted second laser component, and output a first combined laser or a second combined laser. In some embodiments, the first laser, the first laser component, and the second laser component have the same wavelength and the same phase. The first laser, the phase-shifted first laser component, the phase-shifted second laser component, the first combined laser, and the second combined laser may have the same wavelength and / or waveform.

[0069] Specifically, the first beam splitter 303 has two input ports and two output ports. The first beam splitter 303 receives a phase-shifted first laser component and a phase-shifted second laser component from the two input ports, respectively, and outputs a first combined laser beam from the first output port and a second combined laser beam from the second output port. Specifically, the first beam splitter 303 outputs the first combined laser beam when the phase difference between the phase of the phase-shifted first laser component and the phase difference between the phase of the phase-shifted second laser component is 90 degrees; and outputs the second combined laser beam when the phase difference between the phase of the phase-shifted first laser component and the phase difference between the phase of the phase-shifted second laser component is -90 degrees. Therefore, by controlling the phase shifters 304 and 305 to shift the phases of the first and second laser components, the first beam splitter 303 can selectively output either the first combined laser beam or the second combined laser beam.

[0070] Optionally, the laser unit 30 further includes a second polarization rotating beamsplitter 316, located at the optical emitter of the 1×2 optical switch, configured to receive either the first combined laser beam or the second combined laser beam output from the 1×2 optical switch in a time-division manner. The second polarization rotating beamsplitter 316 allows the polarization state of the first combined laser beam to remain unchanged, while changing the polarization state of the second combined laser beam. For example, if both the first and second combined laser beams are TE (or both are TM) light, the second polarization rotating beamsplitter 316 can receive both beams, maintaining the polarization state of the first combined laser beam unchanged (i.e., the first combined laser beam remains TE light (or TM light) after passing through the second polarization rotating beamsplitter 316); and changing the polarization state of the second combined laser beam, i.e., the second combined laser beam becomes TM light (or TE light) after passing through the second polarization rotating beamsplitter 316. The second polarization rotating beam splitter outputs a first combined laser and a second polarization combined laser in 316 time divisions. The first combined laser is TE light (or TM light), and the second polarization combined laser is TM light (or TE light).

[0071] Optionally, each laser transmission detection channel may further include a fourth beam splitter 317. The fourth beam splitter 317 is configured to receive, in a time-division manner, the first combined laser beam or the second polarization combined laser beam output from the second polarization rotating beam splitter 316, splitting the time-division received first combined laser beam or second polarization combined laser beam into a signal combined laser beam and a local oscillator combined laser beam. In this embodiment, since the first combined laser beam and the second polarization combined laser beam are received in a time-division manner, when the fourth beam splitter 317 receives the first combined laser beam, the signal combined laser beam and the local oscillator combined laser beam are respectively the first signal laser beam and the first local oscillator laser beam, and their waveforms, phases, and polarization states are the same as those of the first combined laser beam. When the fourth beam splitter 317 receives the second polarization combined laser beam, the signal combined laser beam and the local oscillator combined laser beam are respectively the second signal laser beam and the second local oscillator laser beam, and their waveforms, phases, and polarization states are the same as those of the second polarization combined laser beam. Therefore, the signal combined laser beam and the local oscillator combined laser beam have different polarization states depending on the time period.

[0072] Optionally, each laser transmission detection channel may also include a circulator 318. The circulator 318 is located at the optical output end of the fourth beam splitter 317 and is configured to receive the first signal laser or the second signal laser output by the fourth beam splitter 317 and transmit the first signal laser or the second signal laser to the circulator's transmission port.

[0073] Optionally, each laser transmission detection channel may also include an angle scan compensator 312. The angle scan compensator 312 is configured to receive the first signal laser and the second signal laser from the circulator 318 in a time-division manner, and to emit the TE light of the first signal laser and the TM light of the second signal laser at different time periods at different angles, wherein the emission directions of the TE light and the TM light differ by a preset angle.

[0074] Specifically, the angle scanning compensator 312 includes a birefringent device 3123 and a rotating mirror 3121. For example... Figure 3E As shown, the birefringent device 3123 is configured to receive either a first signal laser or a second signal laser. Since the first and second signal lasers are TE and TM beams at different times and their polarization directions are different, when the first and second signal lasers are incident on the birefringent device 3123 at the same incident angle, the TE beam and the TM beam are refracted by the birefringent device 3123 with different refractive indices, resulting in different exit angles. Due to the rotation of the rotating mirror, when the TE and TM beams are projected onto the rotating mirror 3121 at different angles, the mirror can emit the TE and TM beams at substantially the same angle. The birefringent device 3123 can be configured such that the exit angles of the TM and TE beams from the birefringent device 3123 match the rotational speed of the rotating mirror 3121, thereby emitting the TE and TM beams from the rotating mirror 3121 at substantially the same angle. For example, the birefringent device 3123 can be a birefringent wedge block. The material and thickness of the birefringent device 3123 can be selected so that the birefringent device 3123 can deflect the TE light at a first angle α and the TM laser at a second angle β. The angle difference |α-β| can be a preset value, which can be matched with the rotation speed of the rotating mirror 3121.

[0075] Optionally, each laser transmission detection channel also includes a detection component 33. The detection component 33 is configured to receive reflected laser light. The reflected laser light can be a reflected beam with a period of T. (Reference) Figure 1 and Figure 3E The up-frequency band of the reflected laser can be a third reflected laser, which can be either TE or TM light; the down-frequency band can be a fourth reflected laser, which can be either TM or TE light. Specifically, the detection component 33 can receive the reflected combined laser beam from the circulator 318.

[0076] Specifically, the detection component may include a mixer 309 configured to receive a first local oscillator laser or a second local oscillator laser and a reflected laser, and to cause optical interference between the first local oscillator laser or the second local oscillator laser and the reflected laser to generate a coherent signal. Optionally, the mixing device may be a coupler, such as a 2×2 coupler.

[0077] Optionally, the detection component 33 may further include a balance detector 310, which may be configured to receive the output signal of the mixer 309, detect the beat frequency during the up-frequency phase and the beat frequency during the down-frequency phase based on the output signal, and output the detection result. The balance detector 310 may be, for example, one or more photodetectors.

[0078] Optionally, the lidar may also include a data acquisition and processing unit 311. The data acquisition and processing unit 311 is configured to receive the output of the balanced detector 310, determine the beat frequency signal based on the output, and obtain the distance and / or velocity information of the target object through calculation.

[0079] Couplers, mixers, balanced detectors, photodetectors, and acquisition and processing devices are common components in the field of FMCW lidar, and will not be described in detail here. Acquisition and processing devices include, for example, a collector and a processor. The collector can convert the detection information, which is an analog signal, into a digital signal, such as an analog-to-digital converter. The processor processes the digital signal to determine the distance and velocity of the lidar relative to the target object. The processor can be, for example, a field-programmable gate array (FPGA) or a digital signal processor (DSP).

[0080] In some embodiments, such as Figures 3A-3E As shown, the lidar also includes a lens assembly 313. The lens assembly 313 is disposed between the circulator 318 and the angle scanning compensator 312, and is configured to collimate the signal laser and focus the reflected laser to couple it into the circulator 318.

[0081] In some embodiments, the lidar further includes a beam scanning guide device disposed between the lens assembly 313 and the target object to achieve light deflection and scanning.

[0082] The lidar disclosed herein can perform angle compensation on the laser emitted by the rotating mirror, thereby avoiding the angle mismatch caused by the two consecutive up-frequency stage signals and down-frequency stage signals during the rotation of the mirror, which can improve measurement accuracy. In addition, the solution of this application only requires one detection component, thereby saving the number of components and reducing the space occupied by the components.

[0083] Figure 3F This is a schematic diagram of the lidar structure of this application. Figure 3F The structure of the lidar shown is similar to Figure 3E The lidar shown has a similar structure. The difference lies in... Figure 3F In this embodiment, the structure of the angle scanning compensator 312 in the lidar differs from that of the other embodiments. Figure 3EThe structure of the angle scanning compensator 312 in the lidar is shown. Specifically, the angle scanning compensator 312 includes a birefringent device 3123 and a rotating mirror 3121, as shown in the figure. Figure 3F As shown, the rotating mirror 3121 is configured to receive the signal laser from the circulator 318 and then project the signal laser onto the birefringent device 3123. The birefringent device 3123 is configured to produce different refractions of the TE and TM beams in the signal laser. Due to the rotation of the rotating mirror, there is an angular difference between the first and second signal laser beams projected by the rotating mirror 3121 onto the birefringent device 3123; this angular difference is called angular mismatch. By configuring the birefringent device 3123, the exit angles of the TE and TM beams can be made the same. Specifically, one or more of the material, thickness, and refractive index of the birefringent device 3123 can be configured or selected so that the TE and TM beams exit the birefringent device 3123 at the same angle. The birefringent device 3123 can deflect the TE light by a first angle α and the TM light by a second angle β. The angle difference |α-β| can be a preset value. This preset value can cancel the angle difference generated by the rotation of the rotating mirror 3121, so that the angles of the TE light and the TM light emitted from the birefringent device 3123 are basically the same, thereby overcoming the angle mismatch problem mentioned above. Figure 3F The working principle of the other devices shown is the same as Figure 3E The corresponding devices shown operate on similar principles; for details, please refer to the above. Figure 3E The relevant descriptions in [the document] are omitted here to avoid duplication.

[0084] Figure 5A and Figure 5B An example autonomous vehicle 500 according to an embodiment of this application is illustrated, which may include the features of this application. Figures 3A-3F Any component of any of the lidars shown. The autonomous vehicle 500 shown includes a sensor array configured to capture information about one or more objects in the autonomous vehicle's external environment and generate sensor data associated with the captured one or more objects for use in controlling the operation of the autonomous vehicle 500. Figure 5 shows sensors 501, 502, 503, 504, and 505. Figure 5B The diagram illustrates sensors 501, 502, 503, 504, 505, 506, 507, 508, and 509. Figure 5B The image shown is a top view of the autonomous vehicle 500. Any of sensors 501, 502, 503, 504, 505, 506, 507, 508, and 509 may include those described in this application. Figures 3A-3F Any of the lidar devices shown, the device includes Figures 3A-3FAny radar component of any one of the above. An autonomous vehicle may include a powertrain comprising a prime mover powered by an energy source and capable of powering a transmission system. An autonomous vehicle may also include a control system comprising steering control, powertrain control, and braking control. An autonomous vehicle can be implemented as any number of different vehicles, including vehicles capable of transporting people and / or goods and capable of operating in a wide variety of environments. It should be understood that the aforementioned components can vary widely depending on the type of vehicle utilizing these components. Detailed descriptions of this embodiment of the present application can be found in the description of the foregoing embodiments. To avoid repetition, these descriptions will not be repeated here.

Claims

1. A lidar, characterized in that, The lidar includes: At least one laser transmission detection channel, wherein each of the at least one laser transmission detection channel comprises: A laser unit is configured to emit a first signal laser and / or emit a second signal laser, wherein the first signal laser and the second signal laser are frequency-modulated lasers, the first signal laser has a frequency-up band, and the second signal laser has a frequency-down band, wherein the wavelength of the first signal laser is different from the wavelength of the second signal laser, or the polarization direction of the first signal laser is different from the polarization direction of the second signal laser; An optical transmitter configured to emit the first signal laser and / or the second signal laser; An angle scanning compensator is configured to receive the first signal laser and the second signal laser from the light emitter in a time-division manner, and to emit the first signal laser and the second signal laser in substantially the same direction, wherein the first signal laser and the second signal laser are reflected upon encountering a target to generate a first reflected laser and a second reflected laser. A detection component is configured to receive the first reflected laser and the second reflected laser, obtain the beat frequency signal of the first reflected laser and the second reflected laser, and output the beat frequency signal; and The acquisition and processing device is configured to determine the speed and / or distance of the target object based on the beat frequency signal.

2. The lidar according to claim 1, wherein, The angle scanning compensator includes a dispersive device, wherein the wavelength of the first signal laser is different from the wavelength of the second signal laser; or The angle scanning compensator includes a birefringent device, and the polarization direction of the first signal laser is different from that of the second signal laser.

3. The lidar according to claim 2, wherein, The angle scanning compensator includes a rotating mirror. The dispersive device or the birefringent device directs the first signal laser and the second signal laser onto the rotating mirror with a first angular deviation, and the rotating mirror directs the first signal laser and the second signal laser in substantially the same direction, or The rotating mirror directs the first signal laser and the second signal laser onto the dispersive device or the birefringent device with a first angular deviation, and the dispersive device or the birefringent device emits the first signal laser and the second signal laser in substantially the same direction.

4. The lidar according to claim 1, wherein, The light emitter includes a first polarization rotating beam splitter or circulator.

5. The lidar according to claim 3, wherein, The laser unit includes: A first laser, configured to generate a first laser beam having a first wavelength; and A second laser is configured to generate a second laser with a second wavelength.

6. The lidar according to claim 5, wherein, The laser unit also includes: A first optical switch is configured to receive the first laser and selectively allow or cut off the first laser. A second optical switch is configured to receive the second laser and selectively allow or cut off the second laser. A first multiplexer is connected to the first optical switch and the second optical switch, and is configured to multiplex the first laser and the second laser, and to output the first laser and the second laser in a time-division multiplexing manner; or The laser unit also includes: A first beam splitter is configured to receive the first laser and the second laser, split the first laser into a first component and a second component, and split the second laser into a first component and a second component. A first phase shifter and a second phase shifter, wherein the first phase shifter is configured to receive a first component of the first laser and a first component of the second laser, and to perform phase shifting on the first component of the first laser and the first component of the second laser; the second phase shifter is configured to receive a second component of the first laser and a second component of the second laser, and to perform phase shifting on the second component of the first laser and the second component of the second laser, such that the phase difference between the phase-shifted first component of the first laser and the phase-shifted second component of the first laser is 0 degrees and the phase difference between the phase-shifted first component of the second laser and the phase-shifted second component of the second laser is 180 degrees, or the phase difference between the phase-shifted first component of the first laser and the phase-shifted second component of the first laser is 180 degrees and the phase difference between the phase-shifted first component of the second laser and the phase-shifted second component of the second laser is 0 degrees. A first combiner is configured to receive a first component of the first laser and a first component of the second laser after phase shifting, and to receive a second component of the first laser and a second component of the second laser after phase shifting, wherein the first combiner outputs the first laser when the phase difference between the first component of the first laser and the second component of the first laser after phase shifting is 0 degrees and the phase difference between the first component of the second laser and the second component of the second laser after phase shifting is 180 degrees, and the first combiner outputs the second laser when the phase difference between the first component of the first laser and the second component of the first laser after phase shifting is 180 degrees and the phase difference between the first component of the second laser and the second component of the second laser after phase shifting is 0 degrees.

7. The lidar according to claim 6, wherein, Each of the at least one laser transmission detection channel further includes: The second beam splitter is configured to receive the first laser and the second laser in a time-division manner, splitting the first laser into a first signal laser and a first local oscillator laser, and splitting the second laser into a second signal laser and a second local oscillator laser.

8. The lidar according to claim 3, wherein, The laser unit includes: A first laser is configured to generate a first laser with a first wavelength; A third beam splitter is configured to receive the first laser beam and split it into a first laser component and a second laser component. A first phase shifter and a second phase shifter, wherein the first phase shifter is configured to receive the first laser component and shift the phase of the first laser component, and the second phase shifter is configured to receive the second laser component and shift the phase of the second laser component, such that the phase of the first laser component and the phase of the second laser component differ by 90 degrees or -90 degrees. A first beam splitter is configured to receive a phase-shifted first laser component and a phase-shifted second laser component, and output a first combined laser or a second combined laser, wherein the first beam splitter outputs the first combined laser when the phase difference between the phase of the phase-shifted first laser component and the phase difference between the phase of the phase-shifted second laser component is 90 degrees; and the first beam splitter outputs the second combined laser when the phase difference between the phase of the phase-shifted first laser component and the phase difference between the phase of the phase-shifted second laser component is -90 degrees.

9. The lidar according to claim 8, wherein, Each of the at least one laser transmission detection channel further includes: The second polarization beam splitter is configured to maintain the polarization direction of the first combined laser beam, change the polarization direction of the second combined laser beam, and output the first combined laser beam with unchanged polarization direction and the second combined laser beam with changed polarization direction.

10. The lidar according to claim 9, wherein, Each of the at least one laser transmission detection channel further includes: The fourth beam splitter is located at the light emitting end of the second polarization rotating beam splitter and is configured to split the first combined laser beam into a first signal laser and a first local oscillator laser, or to split the second combined laser beam into a second signal laser and a second local oscillator laser.

11. The lidar according to claim 7 or 10, wherein the detection component comprises: A first mixer is configured to receive the reflected laser and the first local oscillator laser, or to receive the reflected laser and the second local oscillator laser, and to mix the reflected laser and the first local oscillator laser, or to mix the reflected laser and the second local oscillator laser. A balance detector is configured to receive the output of the first mixer and detect the beat frequency during the up-conversion phase and the beat frequency during the down-conversion phase.

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