Ranging device and lidar system

Abstract

This application provides a ranging device and a lidar system. The ranging device includes a chaotic light source unit, a time-domain modulation unit, and a transceiver scanning calculation unit. The chaotic light source unit outputs a continuous chaotic optical frequency comb signal to the time-domain modulation unit. The time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and performs wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal. The transceiver scanning calculation unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information corresponding to each wavelength channel pulse in the time-domain serial pulsed chaotic signal. This solution uses the time stretching transformation of the time-domain modulation unit to stagger the chaotic pulse waveforms of each wavelength channel of the multiple parallel wavelength channel chaotic pulse signals at equal time intervals on the time axis, so that the signals of multiple wavelength channels can be received and processed through a single detection channel, significantly reducing hardware costs.

Description

Technical Field

[0001] This application relates to the fields of lidar and photoelectric detection technology, and more specifically, to a ranging device and lidar system. Background Technology

[0002] Traditional LiDAR ranging technologies include direct pulse time-of-flight (d-TOF) and frequency modulated continuous wave (FMCW) schemes. When the number of channels increases, multiple systems work simultaneously, or the laser repetition rate is high, the echo signals of these two technologies will alias in the time domain and frequency domain, respectively, leading to distance ambiguity (distance blurring).

[0003] Random Modulated Continuous Wave (RMCW) LiDAR, also known as Chaotic LiDAR, can significantly improve the system's anti-interference performance and eliminate distance ambiguity by introducing random or noise-like coding and using cross-correlation demodulation (matched filtering) technology to obtain the time-of-flight (TOF) information of the echo signal.

[0004] However, existing parallel chaotic LiDAR typically adopts a multi-wavelength parallel + multi-channel detection architecture, which requires each spectral channel to have its own independent detector. This leads to a proportional increase in the number of detectors and channels, resulting in a sharp increase in hardware resources and costs. Summary of the Invention

[0005] The purpose of this application is to provide a ranging device and a lidar system to solve the problem that existing parallel chaotic LiDAR systems require independent detectors for each spectral channel, resulting in a sharp increase in hardware resources and costs.

[0006] In a first aspect, this application provides a ranging device, which includes a chaotic light source unit, a time-domain modulation unit, and a transceiver scanning calculation unit. The chaotic light source unit is used to output a continuous chaotic optical frequency comb signal to the time-domain modulation unit. The continuous chaotic optical frequency comb signal represents an optical frequency comb signal with equal frequency spacing of spectral comb teeth and statistically orthogonal time-frequency domains. The time-domain modulation unit is used to modulate the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, perform wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal, and transmit the time-domain serial pulsed chaotic signal to the transceiver scanning calculation unit. The chaotic pulse waveforms of each wavelength channel of the time-domain serial pulsed chaotic signal are staggered at equal time intervals on the time axis. The transceiver scanning calculation unit is used to calculate the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information corresponding to each wavelength channel pulse in the time-domain serial pulsed chaotic signal. The echo time-domain information is obtained by collecting diffuse reflection light generated by the target object on the two-dimensional scanning beam, and the two-dimensional scanning beam is generated based on the time-domain serial pulsed chaotic signal.

[0007] The ranging device provided in this solution first outputs a continuous chaotic optical frequency comb signal to a time-domain modulation unit through a chaotic light source unit. Then, the time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and performs wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal. Finally, the transceiver scanning unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information corresponding to each wavelength channel pulse in the time-domain serial pulsed chaotic signal, thereby realizing target ranging. Because this solution converts multiple parallel wavelength channel chaotic pulse signals into a time-domain serial signal with the chaotic pulse waveforms of each wavelength channel staggered at equal time intervals on the time axis through the time stretching transformation of the time-domain modulation unit, the signals of multiple wavelength channels can be received and processed through a single detection channel, eliminating the need to configure an independent detector for each wavelength channel, greatly reducing the number of detectors, and thus reducing hardware costs and resource consumption. Meanwhile, after time-domain serialization, the signals from multiple wavelength channels in this scheme allow each channel to independently undertake a portion of the ranging task, with no interference between the signals. This ensures ranging efficiency while leveraging the orthogonality of chaotic signals and the high precision of cross-correlation demodulation to guarantee the ranging accuracy of each wavelength channel. Furthermore, this scheme uses a continuous chaotic optical frequency comb signal as the original signal. Chaotic signals possess the characteristics of random noise, and the time-frequency domain statistics of the signals from each wavelength channel are orthogonal, making them less susceptible to external interference and improving the anti-interference capability of the ranging device.

[0008] In an optional embodiment of the first aspect, the chaotic light source unit includes a laser generator, a polarization controller, an amplification filter, and a microring resonant cavity; the laser generator is used to generate and output continuous laser light; the polarization controller is used to modulate the continuous laser light output by the laser generator to a target polarization state; the amplification filter is used to amplify and denoise the continuous laser light in the target polarization state; and the microring resonant cavity is used to modulate the amplified and denoised continuous laser light into a continuous chaotic optical frequency comb signal using a microring optical waveguide.

[0009] The chaotic light source unit provided in this solution optimizes the laser signal quality step by step through a process of polarization modulation, amplification and denoising, and micro-ring modulation. Among them, polarization modulation ensures signal adaptability, amplification and denoising improves signal purity and intensity, and the micro-ring resonant cavity uses nonlinear effects to accurately generate equally spaced and orthogonal chaotic optical frequency comb signals. The synergistic effect of each step ensures that the generated continuous chaotic optical frequency comb signal meets the subsequent ranging requirements. At the same time, the filtering function of the amplification filter can effectively filter out external noise and device noise, reducing noise interference to the signal.

[0010] In an optional embodiment of the first aspect, the time-domain modulation unit includes a pulse modulator, a wavelength division multiplexer, and a wavelength division multiplexer; the pulse modulator is used to modulate a continuous chaotic optical frequency comb signal into a pulsed chaotic signal and transmit the pulsed chaotic signal to the wavelength division multiplexer; the wavelength division multiplexer is used to decompose the pulsed chaotic signal into multiple wavelength channel chaotic pulses; wherein the waveforms of the multiple wavelength channel chaotic pulses are staggered at equal time intervals on the time axis; the wavelength division multiplexer is used to combine the multiple wavelength channel chaotic pulses to generate a time-domain serial pulsed chaotic signal.

[0011] The time-domain modulation unit provided in this solution achieves the separation and serialization of multi-wavelength channel signals through the synergistic effect of wavelength demultiplexing and wavelength division multiplexing (WDM). This allows signals from multiple wavelength channels to be processed through a single transmission link and a single detection channel, eliminating the need for independent transmission links and detectors for each wavelength channel, further reducing hardware resource consumption and cost. Simultaneously, leveraging the high-precision wavelength identification capabilities of the wavelength demultiplexer and WDM, crosstalk between signals from different wavelength channels is avoided, ensuring the quality of the converted time-domain serial pulse chaotic signal.

[0012] In an optional embodiment of the first aspect, the wavelength demultiplexer is a first arrayed waveguide grating, and the wavelength division multiplexer is a second arrayed waveguide grating; each wavelength channel of the first arrayed waveguide grating is connected to the second arrayed waveguide grating through a corresponding fiber delay line, wherein the lengths of the fiber delay lines connected to each wavelength channel of the first arrayed waveguide grating are distributed in an arithmetic sequence, so that the chaotic pulse waveforms of multiple wavelength channels are staggered at equal time intervals on the time axis.

[0013] The above-described implementation scheme uses an arrayed waveguide grating (AWG) as both a wavelength demultiplexer and a wavelength division multiplexer. The AWG offers advantages such as high wavelength separation accuracy, high channel isolation, uniform bandwidth, and low signal loss. It can accurately separate pulse signals of different wavelengths and efficiently combine signals from multiple wavelength channels, reducing signal loss during separation and combining, and improving signal processing efficiency and quality. Furthermore, the use of an arithmetic sequence of fiber delay lines ensures a fixed time delay difference between adjacent wavelength channels, thereby achieving equal intervals between pulses on the time axis. This avoids signal overlap and crosstalk caused by uneven time intervals. The high stability of the fiber delay lines also ensures consistent time delays and improves signal stability.

[0014] In an optional embodiment of the first aspect, the transceiver scanning calculation unit includes a coaxial transceiver unit, a scanning unit, and an acquisition calculation unit; the coaxial transceiver unit is used to split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio; the scanning unit is used to generate a two-dimensional scanning beam according to the first time-domain serial pulse chaotic signal and emit it to the target object, and receive the diffuse reflection light reflected by the target object, and transmit the diffuse reflection light reflected by the target object to the acquisition calculation unit; the acquisition calculation unit is used to record the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal, and acquire the echo time-domain information of the diffuse reflection light, and calculate the distance information corresponding to each wavelength channel according to the echo time-domain information and the chaotic time-domain information corresponding to each wavelength channel pulse.

[0015] The above-described implementation scheme uses a coaxial transceiver unit to achieve signal beam splitting and coaxial transmission, integrating the transmitting and receiving optical paths together. This eliminates the need for a separate receiving optical path, simplifying the optical path structure and reducing optical path loss. Simultaneously, the units work together to form a closed-loop ranging link, avoiding redundant links in the signal transmission process, improving ranging efficiency, and the coaxial transmission design enhances the stability of signal transmission.

[0016] In an optional embodiment of the first aspect, the coaxial transceiver unit includes a beam splitter and an optical fiber circulator; the beam splitter is used to split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio, transmit the first time-domain serial pulse chaotic signal to a first port of the optical fiber circulator, and transmit the second time-domain serial pulse chaotic signal to the acquisition and computing unit; the optical fiber circulator is used to transmit the first time-domain serial pulse chaotic signal to the scanning unit through a second port, and to receive diffuse reflection light reflected by the target object transmitted by the scanning unit through the second port, and transmit the diffuse reflection light reflected by the target object to the acquisition and computing unit through a third port.

[0017] In the above-described implementation scheme, the beam splitter and the fiber optic circulator work together to achieve beam splitting, transmission, reception, and isolation functions. There is no need to design separate transmission and reception optical paths, which simplifies the optical path structure and reduces signal loss during transmission. At the same time, the unidirectional conduction characteristic of the fiber optic circulator can strictly limit the transmission direction of the optical signal. The transmitted light can only be transmitted from the first port to the second port, and the echo light can only be transmitted from the second port to the third port. The two transmission paths are independent of each other, avoiding the back-reverse interference of the transmitted light with the reception of the echo signal.

[0018] In an optional embodiment of the first aspect, the scanning unit includes a collimator, a blazed grating, and a dual-axis acousto-optic deflector; the collimator is used to collimate the first time-domain serial pulse chaotic signal to form a spatially collimated beam, and transmit the spatially collimated beam to the dual-axis acousto-optic deflector; the dual-axis acousto-optic deflector is used to perform slow-axis acousto-optic scanning on the spatially collimated beam to generate slow-axis outgoing light; the blazed grating is used to disperse the slow-axis outgoing light to achieve fast-axis spectral scanning, generate a two-dimensional scanning beam, and emit it.

[0019] The above-described implementation scheme utilizes the high-speed, inertia-free beam scanning capability of a dual-axis acousto-optic deflector. It coordinates the time-domain modulation unit's time-spacing interval with the acousto-optic deflector's scanning period, ensuring that each multi-channel chaotic sequence emission corresponds to a unique spatial sampling point. This achieves MHz-level three-dimensional point cloud acquisition without redundant retracement, truly leveraging the advantages of high-frequency spectral scanning. Simultaneously, the acousto-optic deflector combines beam emission and echo reception functions, eliminating the need for additional independent receiving devices and simplifying the scanning unit's structure.

[0020] In an optional embodiment of the first aspect, the acquisition and calculation unit includes a detection subunit and a calculation subunit; the detection subunit is used to acquire the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal and convert the chaotic time-domain information corresponding to each wavelength channel pulse into the corresponding digital chaotic time-domain information, and to acquire the echo time-domain information in the diffuse reflection light reflected back by the target object and convert the echo time-domain information into the corresponding digital echo time-domain information; the calculation subunit is used to calculate the distance information corresponding to each wavelength channel based on the digital chaotic time-domain information and the digital echo time-domain information corresponding to each wavelength channel pulse.

[0021] In an optional embodiment of the first aspect, the detection subunit includes a first detector, a second detector, and an analog-to-digital converter, and the computing subunit includes a processor; the first detector is used to acquire chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal; the second detector is used to acquire echo time-domain information in the diffuse reflection light reflected back by the target object; the analog-to-digital converter is used to convert the chaotic time-domain information corresponding to each wavelength channel pulse into corresponding digital chaotic time-domain information, and to convert the echo time-domain information into corresponding digital echo time-domain information; the processor is used to perform digital cross-correlation operation on the digital chaotic time-domain information and the digital echo time-domain information corresponding to each wavelength channel pulse to obtain the round-trip propagation time corresponding to each wavelength channel; and to calculate the distance information corresponding to each wavelength channel based on the round-trip propagation time corresponding to each wavelength channel.

[0022] The two implementation methods described above employ high-precision detectors and analog-to-digital converters to ensure the accuracy of photoelectric conversion and analog-to-digital conversion, reducing conversion errors. The processor has high-speed parallel processing capabilities, which can quickly complete cross-correlation calculations and time-of-flight calculations for multi-wavelength channel signals, and output distance information in real time. At the same time, cross-correlation demodulation technology can accurately extract the time of flight, avoid distance ambiguity, further improve calculation accuracy, and achieve millimeter-level ranging error.

[0023] In a second aspect, this application provides a lidar system, including a three-dimensional imaging unit and a ranging device as described in any optional embodiment of the first aspect; the three-dimensional imaging unit is used to generate three-dimensional imaging information corresponding to the target object based on the distance information corresponding to each wavelength channel and the scanning angle.

[0024] The lidar system provided in this solution includes the ranging device described above. Therefore, the designed lidar system can output a continuous chaotic optical frequency comb signal to the time-domain modulation unit through the chaotic light source unit. Then, the time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and performs wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal. Finally, the transceiver scanning unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information of each wavelength channel pulse in the time-domain serial pulsed chaotic signal, thereby realizing target ranging. Because this solution converts multiple parallel wavelength channel chaotic pulse signals into a time-domain serial signal with the chaotic pulse waveforms of each wavelength channel staggered at equal time intervals on the time axis through the time stretching transformation of the time-domain modulation unit, the signals of multiple wavelength channels can be received and processed through a single detection channel. There is no need to configure an independent detector for each wavelength channel, which greatly reduces the number of detectors and thus reduces the hardware cost and resource consumption of the lidar system.

[0025] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1This is a schematic diagram of the first structure of the ranging device provided in the embodiments of this application; Figure 2 This is a schematic diagram of the second structure of the ranging device provided in the embodiments of this application; Figure 3 This is a schematic diagram of the third structure of the ranging device provided in the embodiments of this application; Figure 4 This is a schematic diagram of the fourth structure of the ranging device provided in the embodiments of this application; Figure 5 This is a schematic diagram of the fifth structure of the ranging device provided in the embodiments of this application; Figure 6 This is a schematic diagram of the sixth structure of the ranging device provided in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of a lidar system provided in an embodiment of this application.

[0028] Icons: 1-3D imaging unit; 2-range measuring device; 10-chaotic light source unit; 110-laser generator; 120-polarization controller; 130-amplifier filter; 1310-amplifier; 1320-spectral filter; 140-micro-ring resonator; 20-time-domain modulation unit; 210-pulse modulator; 220-wavelength demultiplexer; 230-wavelength division multiplexer; AWG1-first array waveguide grating; AWG2-second array waveguide grating Grid; 30-Transceiver scanning and computing unit; 310-Coaxial transceiver unit; 3110-Bow splitter; 3120-Fiber circulator; 320-Scanning unit; 3210-Collider; 3220-Blazed grating; 3230-Dual-axis acousto-optic deflector; 330-Acquisition and computing unit; 3310-Detector subunit; PD1-First detector; PD2-Second detector; ADC-Analog-to-digital converter; 3320-Computing subunit; CPU-Processor. Detailed Implementation

[0029] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0031] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments in this application, the term "and / or" 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] Traditional LiDAR ranging technologies include direct pulse time-of-flight (d-TOF) and frequency modulated continuous wave (FMCW) schemes. When the number of channels increases, multiple systems work simultaneously, or the laser repetition rate is high, the echo signals of these two technologies will alias in the time domain and frequency domain, respectively, leading to distance ambiguity (distance blurring).

[0038] Random Modulated Continuous Wave (RMCW) LiDAR, also known as Chaotic LiDAR, can significantly improve the system's anti-interference performance and eliminate distance ambiguity by introducing random or noise-like coding and using cross-correlation demodulation (matched filtering) technology to obtain the time-of-flight (TOF) information of the echo signal.

[0039] However, existing parallel chaotic LiDAR typically adopts a multi-wavelength parallel + multi-channel detection architecture, which requires each spectral channel to have its own independent detector. This leads to a proportional increase in the number of detectors and channels, resulting in a sharp increase in hardware resources and costs.

[0040] To address the aforementioned issues, this application provides a ranging device and a lidar system. First, a continuous chaotic optical frequency comb signal is output to a time-domain modulation unit via a chaotic light source unit. Then, the time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal. Furthermore, the pulsed chaotic signal undergoes wavelength division multiplexing and time stretching transformation to generate a time-domain serial pulsed chaotic signal. Finally, a transceiver scanning unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information of each wavelength channel pulse in the time-domain serial pulsed chaotic signal, thereby achieving target ranging. Because this scheme uses the time stretching transformation of the time-domain modulation unit to convert multiple parallel wavelength channel chaotic pulse signals into a time-domain serial signal with each wavelength channel's chaotic pulse waveform staggered at equal time intervals on the time axis, signals from multiple wavelength channels can be received and processed through a single detection channel. This eliminates the need for an independent detector for each wavelength channel, significantly reducing the number of detectors and thus lowering hardware costs and resource consumption.

[0041] Based on the above ideas, this application first provides a ranging device, such as... Figure 1 As shown, the ranging device includes a chaotic light source unit 10, a time-domain modulation unit 20, and a transceiver scanning calculation unit 30.

[0042] In this scheme, the chaotic light source unit 10 represents the functional unit that generates and outputs a continuous chaotic optical frequency comb signal. It is the optical signal source of the entire ranging device. The continuous chaotic optical frequency comb signal represents an optical frequency comb signal with equal frequency spacing of spectral comb teeth and statistical orthogonality in the time and frequency domains. This statistical orthogonality in the time and frequency domains ensures that no crosstalk will be generated during subsequent multi-channel signal processing, providing a basis for parallel ranging. Its generation can be achieved by using the nonlinear effect of the micro-ring resonator and generating a chaotic optical signal with an equidistant comb tooth structure by continuous laser pumping.

[0043] The time-domain modulation unit 20 represents a functional unit that modulates, wavelength-division multiplexes, and performs time-stretch transformation on the continuous chaotic optical frequency comb signal output by the chaotic light source unit 10 to achieve serialization of multi-wavelength channel signals. The transceiver scanning calculation unit 30 represents a functional unit responsible for transmitting optical signals, acquiring echo signals, and calculating distance information; it is the core execution unit for distance measurement.

[0044] Specifically, in the application of the above-designed ranging device, the chaotic light source unit 10 first generates and outputs the continuous chaotic optical frequency comb signal. The time-domain modulation unit 20 first modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, preserving the anti-interference characteristics of the chaotic signal. The time-domain modulation unit 20 then performs wavelength division multiplexing on the pulsed chaotic signal, decomposing it into multiple independent wavelength channel chaotic pulses. Then, through time stretching transformation, these wavelength channel chaotic pulses are staggered at equal time intervals on the time axis, and finally synthesized into a time-domain serial pulsed chaotic signal. After receiving the time-domain serial pulsed chaotic signal transmitted by the time-domain modulation unit 20, the transceiver scanning calculation unit 30 generates a two-dimensional scanning beam based on the time-domain serial pulsed chaotic signal and emits it to the target object. On the other hand, it collects the diffuse reflection light reflected by the target object to obtain the echo time-domain information. Finally, by comparing the chaotic time-domain information (transmitter reference signal) corresponding to each wavelength channel pulse with the echo time-domain information (receiver reflection signal), the distance information corresponding to each wavelength channel is calculated, thereby realizing the ranging of the target object.

[0045] The ranging device provided in this solution first outputs a continuous chaotic optical frequency comb signal to a time-domain modulation unit through a chaotic light source unit. Then, the time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and performs wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal. Finally, the transceiver scanning unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information corresponding to each wavelength channel pulse in the time-domain serial pulsed chaotic signal, thereby realizing target ranging. Because this solution converts multiple parallel wavelength channel chaotic pulse signals into a time-domain serial signal with the chaotic pulse waveforms of each wavelength channel staggered at equal time intervals on the time axis through the time stretching transformation of the time-domain modulation unit, the signals of multiple wavelength channels can be received and processed through a single detection channel, eliminating the need to configure an independent detector for each wavelength channel, greatly reducing the number of detectors, and thus reducing hardware costs and resource consumption. Meanwhile, after time-domain serialization, the signals from multiple wavelength channels in this scheme allow each channel to independently undertake a portion of the ranging task, with no interference between the signals. This ensures ranging efficiency while leveraging the orthogonality of chaotic signals and the high precision of cross-correlation demodulation to guarantee the ranging accuracy of each wavelength channel. Furthermore, this scheme uses a continuous chaotic optical frequency comb signal as the original signal. Chaotic signals possess the characteristics of random noise, and the time-frequency domain statistics of the signals from each wavelength channel are orthogonal, making them less susceptible to external interference and improving the anti-interference capability of the ranging device.

[0046] In an optional implementation of this embodiment, such as Figure 2 As shown, the chaotic light source unit 10 designed in this scheme includes a laser generator 110, a polarization controller 120, an amplification filter 130, and a micro-ring resonator 140. The output terminal of the laser generator 110 is connected to the input terminal of the polarization controller 120, the output terminal of the polarization controller 120 is connected to the input terminal of the amplification filter 130, and the output terminal of the amplification filter 130 is connected to the input terminal of the micro-ring resonator 140. The output terminal of the micro-ring resonator 140 serves as the output terminal of the chaotic light source unit 10 and is connected to the input terminal of the time-domain modulation unit 20. The amplification filter 130 can be composed of an amplifier 1310 and a spectral filter 1320.

[0047] The chaotic light source unit 10 designed above has a laser generator 110 that generates continuous laser light and transmits it to a polarization controller 120. After receiving the continuous laser light, the polarization controller 120 modulates the polarization direction of the laser light according to a preset target polarization state. Since subsequent devices such as the amplification filter 130 and the micro-ring resonator 140 have specific requirements for the polarization state of the laser light, polarization modulation can ensure that the laser light can pass through these devices efficiently, reduce signal loss, avoid signal distortion caused by polarization inconsistency, and ensure the stability of subsequent signal processing.

[0048] The amplification filter 130 receives the polarization-modulated continuous laser. On the one hand, it increases the power of the laser through the amplification module to meet the power requirements of the micro-ring resonator modulation. On the other hand, it filters out clutter and noise in the laser through the filtering module to improve the purity of the laser signal. Finally, the micro-ring resonator 140 receives the amplified and denoised continuous laser. By adjusting the pump power and detuning, the micro-ring enters a chaotic modulation unsteady state and finally outputs a continuous chaotic optical frequency comb signal. Specifically, the laser generator 110 used in this scheme can be a pump laser or other types of laser generator, the amplification filter 130 can be an erbium-doped fiber amplifier or other types of amplification filter, and the micro-ring resonator 140 can be made of different material platforms, such as silicon nitride (Si3N4), gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium arsenide (AlGaAs), etc., as long as it can generate a chaotic optical frequency comb with a large FSR (tens to hundreds of GHz) and orthogonal time-frequency statistics on the chip; the number or structure of the micro-rings can be a single ring, multi-ring cascade, or other microcavity structures, as long as the output meets the characteristics of a multi-comb chaotic optical frequency comb.

[0049] The chaotic light source unit provided in this solution optimizes the laser signal quality step by step through a process of polarization modulation, amplification and denoising, and micro-ring modulation. Among them, polarization modulation ensures signal adaptability, amplification and denoising improves signal purity and intensity, and the micro-ring resonant cavity uses nonlinear effects to accurately generate equally spaced and orthogonal chaotic optical frequency comb signals. The synergistic effect of each step ensures that the generated continuous chaotic optical frequency comb signal meets the subsequent ranging requirements. At the same time, the filtering function of the amplification filter can effectively filter out external noise and device noise, reducing noise interference to the signal.

[0050] In an optional implementation of this embodiment, such as Figure 3 As shown, the time-domain modulation unit 20 designed in this scheme includes a pulse modulator 210, a wavelength division multiplexer 220, and a wavelength division multiplexer 230. The input terminal of the pulse modulator 210 serves as the input terminal of the time-domain modulation unit 20 and is connected to the output terminal of the chaotic light source unit 10. The output terminal of the pulse modulator 210 is connected to the input terminal of the wavelength division multiplexer 220. The output terminal of the wavelength division multiplexer 220 is connected to the input terminal of the wavelength division multiplexer 230. The output terminal of the wavelength division multiplexer 230 serves as the output terminal of the time-domain modulation unit 20 and is connected to the input terminal of the transceiver scanning calculation unit 30.

[0051] The time-domain modulation unit 20 and pulse modulator 210 of the above design receive the continuous chaotic optical frequency comb signal output by the chaotic light source unit 10. According to the preset pulse parameters, the continuous chaotic optical signal is pulse-cut and modulated into a pulsed chaotic signal. The core of pulse modulation is to preserve the time-frequency domain orthogonality and random noise characteristics of the chaotic signal, while converting the continuous signal into discrete pulses, providing a basis for subsequent wavelength separation and time stretching transformation. The pulse parameters can be flexibly adjusted according to the ranging accuracy and rate requirements to ensure that the pulse signal can be adapted to subsequent wavelength decomposition multiplexing and time stretching processing.

[0052] After receiving the pulsed chaotic signal, the wavelength demultiplexer 220 uses the wavelength separation principle to separate the pulsed chaotic signal, which is mixed with multiple wavelength channels, into multiple chaotic pulses of a single wavelength. Since each tooth of the continuous chaotic optical frequency comb signal corresponds to a different wavelength, and their time-frequency domain statistics are orthogonal, the wavelength demultiplexer can accurately identify and separate the pulse signal corresponding to each wavelength. Simultaneously, it ensures that the chaotic pulse waveforms of each separated wavelength channel are staggered at equal time intervals on the time axis, preparing for subsequent serial beam combining.

[0053] Wavelength division multiplexer 230 receives multiple wavelength channel chaotic pulses separated by wavelength demultiplexer 220, bundles these pulse signals into the same transmission medium, generates a time-domain serial pulse chaotic signal, and transmits it to transceiver scanning calculation unit 30. Although the time-domain serial pulse chaotic signal is still a multi-wavelength channel chaotic parallel signal in the frequency domain, it has been serialized with different wavelengths in the time domain.

[0054] The time-domain modulation unit provided in this solution achieves the separation and serialization of multi-wavelength channel signals through the synergistic effect of wavelength demultiplexing and wavelength division multiplexing (WDM). This allows signals from multiple wavelength channels to be processed through a single transmission link and a single detection channel, eliminating the need for independent transmission links and detectors for each wavelength channel, further reducing hardware resource consumption and cost. Simultaneously, leveraging the high-precision wavelength identification capabilities of the wavelength demultiplexer and WDM, crosstalk between signals from different wavelength channels is avoided, ensuring the quality of the converted time-domain serial pulse chaotic signal.

[0055] In an optional embodiment of this example, as shown in FIG4, the wavelength division multiplexer 220 designed in this scheme can be a first arrayed waveguide grating AWG1, and the wavelength division multiplexer 230 can be a second arrayed waveguide grating AWG2. Each wavelength channel of the first arrayed waveguide grating AWG1 is connected to the second arrayed waveguide grating AWG2 through a corresponding fiber delay line. The lengths of the fiber delay lines connected to each wavelength channel of the first arrayed waveguide grating AWG1 are distributed in an arithmetic sequence.

[0056] The pulse chaotic signal generated by the pulse modulator 210 in the time-domain modulation unit 20 designed above is transmitted to the first arrayed waveguide grating AWG1. The first arrayed waveguide grating AWG1 uses its own wavelength separation characteristics to decompose the mixed pulse chaotic signal into multiple single-wavelength channel chaotic pulses. The chaotic pulse of each wavelength channel is output from the corresponding output end of the first arrayed waveguide grating AWG1. The chaotic pulse of each wavelength channel is transmitted to the second arrayed waveguide grating AWG2 through the corresponding fiber delay line. Since the length of the fiber delay line is distributed in an arithmetic sequence, the time difference between the pulse signals of two adjacent wavelength channels propagating in the fiber delay line is a fixed value. Therefore, after passing through the fiber delay line, the chaotic pulses of each wavelength channel form a staggered distribution with equal time intervals on the time axis, realizing time stretching transformation. The second arrayed waveguide grating AWG2 receives the multiple wavelength channel chaotic pulses after time delay adjustment and uses its own wavelength division multiplexing characteristics to bundle these pulse signals into the same transmission medium to generate a time-domain serial pulse chaotic signal.

[0057] The above-described embodiments of this design employ arrayed waveguide gratings (AWGs) as wavelength demultiplexers and wavelength division multiplexers. AWGs offer advantages such as high wavelength separation accuracy, high channel isolation, uniform bandwidth, and low signal loss. They can accurately separate pulse signals of different wavelengths and efficiently combine signals from multiple wavelength channels, reducing signal loss during separation and combining, and improving signal processing efficiency and quality. Furthermore, the use of arithmetic progression fiber delay lines ensures a fixed time delay difference between pulse signals from adjacent wavelength channels, thereby achieving equal intervals between pulses on the time axis. This avoids signal overlap and crosstalk caused by uneven time intervals. The high stability of the fiber delay lines also ensures consistent time delays and improves signal stability.

[0058] Additionally, it should be noted that, in addition to arrayed waveguide gratings (AWGs), the wavelength division multiplexing devices in this scheme can also be thin-film filter arrays, tunable filter matrices, grating coupler arrays, etc., as long as they can achieve multi-channel wavelength division multiplexing of chaotic optical frequency combs. The fiber delay line used in this scheme can be replaced with integrated photonic waveguide delay line, high-dispersion fiber, dispersion-compensated fiber, fiber Bragg grating array, or free-space delay scheme based on dispersion grating, etc., as long as it can stretch and stagger the wavelength channels on the time axis.

[0059] In an optional implementation of this embodiment, such as Figure 5 As shown, the transceiver scanning calculation unit 30 designed in this scheme may include a coaxial transceiver unit 310, a scanning unit 320, and an acquisition calculation unit 330.

[0060] The transceiver scanning calculation unit 30 and coaxial transceiver unit 310 designed above split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio. Then, the first time-domain serial pulse chaotic signal is transmitted to the scanning unit 320, and the second time-domain serial pulse chaotic signal is transmitted to the acquisition calculation unit 330. The beam splitting ratio can be adjusted according to the actual ranging requirements (such as a first time-domain serial pulse chaotic signal: second time-domain serial pulse chaotic signal ratio of 9:1, 8:2, or 7:3) to ensure that the transmitted signal has sufficient power, while the reference signal has clear chaotic time-domain characteristics to meet the requirements of subsequent cross-correlation calculations. Beam splitters and other devices can be used during the beam splitting process to ensure the uniformity and stability of the signal beam splitting.

[0061] The scanning unit 320 generates a two-dimensional scanning beam based on the first time-domain serial pulse chaotic signal and emits it towards the target object. It also receives the diffuse reflected light from the target object and transmits the diffuse reflected light to the acquisition and calculation unit 330. The two-dimensional scanning can cover a larger detection area, enabling wide-range ranging. The scanning method can employ efficient methods such as acousto-optic scanning to improve scanning speed and accuracy, ensuring that the beam can uniformly cover all areas of the target object.

[0062] The acquisition and calculation unit 330 records the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal transmitted by the coaxial transceiver unit 310, as well as the echo time-domain information of the diffuse reflection light transmitted by the acquisition and scanning unit 320. Then, based on the echo time-domain information and the chaotic time-domain information corresponding to each wavelength channel pulse, the distance information corresponding to each wavelength channel is calculated.

[0063] The transceiver scanning calculation unit designed in this scheme uses a coaxial transceiver unit to achieve signal beam splitting and coaxial transmission, integrating the transmitting optical path and the receiving optical path together. This eliminates the need for a separate receiving optical path, simplifies the optical path structure, and reduces optical path loss. At the same time, the units work together to form a closed-loop ranging link, avoiding redundant links in the signal transmission process, improving ranging efficiency, and the coaxial transmission design can improve the stability of signal transmission.

[0064] In an optional implementation of this embodiment, such as Figure 6 As shown, the coaxial transceiver unit 310 designed in this scheme may include a beam splitter 3110 and an optical fiber circulator 3120.

[0065] The designed beam splitter 3110 can split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio. The first time-domain serial pulse chaotic signal is transmitted to the first port of the fiber optic circulator 3120, and the second time-domain serial pulse chaotic signal is transmitted to the acquisition and computing unit 330.

[0066] The fiber optic circulator 3120 transmits the first time-domain serial pulse chaotic signal to the scanning unit 320 through the second port, and receives the diffuse reflection light reflected by the target object transmitted by the scanning unit 320 through the second port, and transmits the diffuse reflection light reflected by the target object to the acquisition and calculation unit 330 through the third port, thereby completing the optical path separation of coaxial transmission and reception.

[0067] It should be noted that in the coaxial optical path multiplexing structure implemented in this invention, the fiber optic circulator can be replaced with a polarization beam splitter-combiner structure or other optical devices capable of coaxial multiplexing and separation of the transmitting / receiving optical paths. Furthermore, in other embodiments, a non-coaxial transceiver system can also be used, such as a receiving optical path separate from the transmitting optical path achieved by combining a lens and a single-pixel detector, as long as effective collection of target echoes and single-pixel detection can be achieved. This application is not limited to coaxial transceiver.

[0068] The coaxial transceiver unit 310, beam splitter 3110, and fiber optic circulator 3120 designed above work together to achieve beam splitting, transmission, reception, and isolation functions. There is no need to design separate transmission and reception optical paths, which simplifies the optical path structure and reduces signal loss during transmission. At the same time, the unidirectional conduction characteristic of the fiber optic circulator can strictly limit the transmission direction of the optical signal. The transmitted light can only be transmitted from the first port to the second port, and the echo light can only be transmitted from the second port to the third port. The two transmission paths are independent of each other, avoiding the back-reverse interference of the transmitted light with the reception of the echo signal.

[0069] In an optional implementation of this embodiment, such as Figure 6 As shown, the scanning unit 320 designed in this scheme may include a collimator 3210, a blazed grating 3220, and a dual-axis acousto-optic deflector 3230. The input end of the collimating lens is connected to the second port of the fiber optic circulator, and the output end of the collimating lens is connected to the input end of the dual-axis acousto-optic deflector.

[0070] The scanning unit 320 designed above has a collimator 3210 that collimates the first time-domain serial pulse chaotic signal to form a spatially collimated beam, and transmits the spatially collimated beam to the dual-axis acousto-optic deflector 3230; the dual-axis acousto-optic deflector 3230 performs slow-axis acousto-optic scanning on the spatially collimated beam to generate slow-axis outgoing light; the blazed grating 3220 disperses the slow-axis outgoing light to achieve fast-axis spectral scanning, generating a two-dimensional scanning beam and emitting it; at the same time, the dual-axis acousto-optic deflector 3230 has an echo light receiving function, receiving the diffuse reflection light reflected by the target object, and transmitting it in reverse to the collimator 3210, and then through the collimator 3210 to the second port of the fiber optic circulator 3120 to complete the reception and transmission of the echo light.

[0071] It should be noted that the above embodiments are merely one example of implementing the scanning unit. The scanning unit for beam scanning is not limited to the spectral-acoustic-optical scanning structure used in the specific embodiments. It can employ any device or structure capable of scanning the emitted beam or the receiving field of view in space in a predetermined manner, such as mechanical scanning mechanisms (e.g., galvanometers, fast-reflecting mirrors, wedge mirrors, rotating mirrors, etc.), MEMS micromirrors based on microelectromechanical systems (MEMS), or optical phased arrays (OPA), or any combination of the fast and slow axes of the above technologies. As long as two-dimensional scanning of the observation area can be achieved, it can be considered an equivalent replacement for the scanning unit of the present invention.

[0072] The scanning unit provided in this solution utilizes the high-speed, inertia-free beam scanning capability of a dual-axis acousto-optic deflector. It coordinates the time-domain modulation unit's time-spacing interval with the acousto-optic deflector's scanning period, ensuring that each multi-channel chaotic sequence emission corresponds to a unique spatial sampling point. This achieves MHz-level 3D point cloud acquisition without redundant retracement, truly leveraging the advantages of high-frequency spectral scanning. Simultaneously, the acousto-optic deflector combines beam emission and echo reception functions, eliminating the need for additional independent receiving devices and simplifying the scanning unit's structure.

[0073] In an optional implementation of this embodiment, such as Figure 5 and Figure 6 As shown, the acquisition and computing unit 330 designed in this scheme includes a detection subunit 3310 and a computing subunit 3320. The detection subunit 3310 includes a first detector PD1, a second detector PD2, and an analog-to-digital converter (ADC). The computing subunit 3320 includes a processor (CPU). Specifically, the first detector PD1 and the second detector PD2 in this scheme can be avalanche photodiodes (APDs), PIN photodiodes, or other high-speed single-pixel detectors.

[0074] The acquisition and computing unit 330 designed above has a first detector PD1 that can acquire the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal and convert it into the corresponding analog signal and transmit it to the analog-to-digital converter ADC. The second detector PD2 can acquire the echo time-domain information in the diffuse reflection light reflected back by the target object and convert it into the corresponding analog signal and transmit it to the analog-to-digital converter ADC.

[0075] The analog-to-digital converter (ADC) can convert the analog signal corresponding to the chaotic time domain information of each wavelength channel pulse into the corresponding digital chaotic time domain information, and convert the analog signal corresponding to the echo time domain information into the corresponding digital echo time domain information. The ADC then transmits the digital chaotic time domain information and the digital echo time domain information to the CPU. The CPU performs digital cross-correlation on the digital chaotic time domain information and the digital echo time domain information corresponding to each wavelength channel pulse to obtain the round-trip propagation time for each wavelength channel. Based on the round-trip propagation time for each wavelength channel, the CPU calculates the distance information for each wavelength channel.

[0076] Specifically, the CPU can first slice the reference channel signal according to a discrete time window, extract the digital chaotic time-domain information corresponding to each wavelength channel pulse, obtain the target orientation information based on the wavelength channel and scanning position, and then perform cross-correlation calculation on the echo signal and the digital chaotic time-domain information corresponding to each wavelength channel pulse to obtain the correlation curve that changes with time delay. The CPU can then find the correlation peak position on the correlation curve and the corresponding time delay. This refers to the round-trip propagation time (TOF) of the k-th wavelength channel. The distance information for each wavelength channel can be calculated using the basic ranging formula: ; In the formula At the speed of light, It represents the distance in the spatial direction corresponding to the k-th channel.

[0077] The acquisition and computing unit provided in this solution uses a high-precision detector and an analog-to-digital converter to ensure the accuracy of photoelectric conversion and analog-to-digital conversion and reduce conversion errors. The processor has high-speed parallel processing capabilities, which can quickly complete the cross-correlation operation and time-of-flight calculation of multi-wavelength channel signals and output distance information in real time. At the same time, the cross-correlation demodulation technology can accurately extract the time of flight, avoid distance ambiguity, further improve the calculation accuracy, and achieve millimeter-level ranging error.

[0078] This application also provides a lidar system, such as Figure 7 As shown, the lidar system includes a three-dimensional imaging unit 1 and a ranging device 2 of any of the optional embodiments described above. The three-dimensional imaging unit 1 can generate three-dimensional imaging information of the target object based on the distance information corresponding to each wavelength channel and the scanning angle output by the ranging device 2. Specifically, the three-dimensional imaging unit 1 can map the distance information corresponding to each wavelength channel and the scanning angle to a three-dimensional coordinate system in space to construct corresponding point cloud data. It can then use continuous frame data to reconstruct the three-dimensional shape and motion trajectory of the target object to achieve rapid 3D imaging.

[0079] The lidar system provided in this solution includes the ranging device described above. Therefore, the designed lidar system can output a continuous chaotic optical frequency comb signal to the time-domain modulation unit through the chaotic light source unit. Then, the time-domain modulation unit modulates the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and performs wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal. Finally, the transceiver scanning unit calculates the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information of each wavelength channel pulse in the time-domain serial pulsed chaotic signal, thereby realizing target ranging. Because this solution converts multiple parallel wavelength channel chaotic pulse signals into a time-domain serial signal with the chaotic pulse waveforms of each wavelength channel staggered at equal time intervals on the time axis through the time stretching transformation of the time-domain modulation unit, the signals of multiple wavelength channels can be received and processed through a single detection channel. There is no need to configure an independent detector for each wavelength channel, which greatly reduces the number of detectors and thus reduces the hardware cost and resource consumption of the lidar system.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A ranging device, characterized in that, The ranging device includes a chaotic light source unit, a time-domain modulation unit, and a transceiver scanning calculation unit. The chaotic light source unit is used to output a continuous chaotic optical frequency comb signal to the time-domain modulation unit; wherein, the continuous chaotic optical frequency comb signal represents an optical frequency comb signal with equal spectral comb tooth frequency intervals and orthogonal time-frequency domain statistics; The time-domain modulation unit is used to modulate the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, perform wavelength division multiplexing and time stretching transformation on the pulsed chaotic signal to generate a time-domain serial pulsed chaotic signal, and transmit the time-domain serial pulsed chaotic signal to the transceiver scanning calculation unit; wherein, the chaotic pulse waveforms of each wavelength channel of the time-domain serial pulsed chaotic signal are staggered at equal time intervals on the time axis. The transceiver scanning calculation unit is used to calculate the distance information corresponding to each wavelength channel based on the chaotic time-domain information and echo time-domain information corresponding to each wavelength channel pulse in the time-domain serial pulse chaotic signal; wherein, the echo time-domain information is obtained by collecting the diffuse reflection light generated by the target object on the two-dimensional scanning beam, and the two-dimensional scanning beam is generated based on the time-domain serial pulse chaotic signal.

2. The ranging device according to claim 1, characterized in that, The chaotic light source unit includes a laser generator, a polarization controller, an amplification filter, and a micro-ring resonant cavity; The laser generator is used to generate and output continuous laser light; The polarization controller is used to modulate the continuous laser output from the laser generator to the target polarization state; The amplification filter is used to amplify and denoise continuous laser light in the target polarization state; The microring resonant cavity is used to modulate the amplified and denoised continuous laser into the continuous chaotic optical frequency comb signal using a microring optical waveguide.

3. The ranging device according to claim 1, characterized in that, The time-domain modulation unit includes a pulse modulator, a wavelength demultiplexer, and a wavelength division multiplexer. The pulse modulator is used to modulate the continuous chaotic optical frequency comb signal into a pulsed chaotic signal, and transmit the pulsed chaotic signal to the wave demultiplexer; The wave demultiplexer is used to decompose the pulse chaotic signal into multiple wavelength channel chaotic pulses; wherein the waveforms of the multiple wavelength channel chaotic pulses are staggered at equal time intervals on the time axis; The wavelength division multiplexer is used to combine the chaotic pulses from the multiple wavelength channels to generate the time-domain serial pulse chaotic signal.

4. The ranging device according to claim 3, characterized in that, The wavelength division multiplexer is a first arrayed waveguide grating and the wavelength division multiplexer is a second arrayed waveguide grating. Each wavelength channel of the first arrayed waveguide grating is connected to the second arrayed waveguide grating through a corresponding fiber delay line. The lengths of the fiber delay lines connected to each wavelength channel of the first arrayed waveguide grating are distributed in an arithmetic sequence, so that the chaotic pulse waveforms of the multiple wavelength channels are staggered at equal time intervals on the time axis.

5. The ranging device according to claim 1, characterized in that, The transceiver scanning calculation unit includes a coaxial transceiver unit, a scanning unit, and an acquisition calculation unit. The coaxial transceiver unit is used to split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio. The scanning unit is used to generate a two-dimensional scanning beam according to the first time-domain serial pulse chaotic signal and emit it to the target object, and to receive the diffuse reflection light reflected by the target object and transmit the diffuse reflection light reflected by the target object to the acquisition and calculation unit. The acquisition and calculation unit is used to record the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal, and to acquire the echo time-domain information of the diffuse reflection light. Based on the echo time-domain information and the chaotic time-domain information corresponding to each wavelength channel pulse, the unit calculates the distance information corresponding to each wavelength channel.

6. The ranging device according to claim 5, characterized in that, The coaxial transceiver unit includes a beam splitter and an optical fiber circulator. The beam splitter is used to split the time-domain serial pulse chaotic signal into a first time-domain serial pulse chaotic signal and a second time-domain serial pulse chaotic signal according to a preset ratio, transmit the first time-domain serial pulse chaotic signal to the first port of the fiber optic circulator, and transmit the second time-domain serial pulse chaotic signal to the acquisition and calculation unit. The fiber optic circulator is used to transmit the first time-domain serial pulse chaotic signal to the scanning unit through the second port, and to receive the diffuse reflection light reflected by the target object transmitted by the scanning unit through the second port, and to transmit the diffuse reflection light reflected by the target object to the acquisition and calculation unit through the third port.

7. The ranging device according to claim 5, characterized in that, The scanning unit includes a collimator, a blazed grating, and a dual-axis acousto-optic deflector; The collimator is used to collimate the first time-domain serial pulse chaotic signal to form a spatial collimated beam, and transmit the spatial collimated beam to the dual-axis acousto-optic deflector; The dual-axis acousto-optic deflector is used to perform slow-axis acousto-optic scanning on the spatial collimated beam to generate slow-axis outgoing light. The blazed grating is used to disperse the slow-axis emitted light, realize fast-axis spectral scanning, generate the two-dimensional scanning beam, and emit it.

8. The ranging device according to claim 5, characterized in that, The acquisition and calculation unit includes a detection subunit and a calculation subunit; The detection subunit is used to collect the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal and convert the chaotic time-domain information corresponding to each wavelength channel pulse into the corresponding digital chaotic time-domain information, and to collect the echo time-domain information in the diffuse reflection light reflected back by the target object and convert the echo time-domain information into the corresponding digital echo time-domain information. The calculation subunit is used to calculate the distance information corresponding to each wavelength channel based on the digital chaotic time-domain information corresponding to each wavelength channel pulse and the digital echo time-domain information.

9. The ranging device according to claim 8, characterized in that, The detection subunit includes a first detector, a second detector, and an analog-to-digital converter; the computing subunit includes a processor. The first detector is used to collect the chaotic time-domain information corresponding to each wavelength channel pulse in the second time-domain serial pulse chaotic signal; The second detector is used to collect the time-domain information of the echo in the diffuse reflected light from the target object; The analog-to-digital converter is used to convert the chaotic time-domain information corresponding to each wavelength channel pulse into the corresponding digital chaotic time-domain information, and to convert the echo time-domain information into the corresponding digital echo time-domain information. The processor is used to perform digital cross-correlation calculations on the digital chaotic time-domain information and the digital echo time-domain information corresponding to each wavelength channel pulse to obtain the round-trip propagation time corresponding to each wavelength channel. The distance information for each wavelength channel is calculated based on the round-trip propagation time for each wavelength channel.

10. A lidar system, characterized in that, The lidar system includes a three-dimensional imaging unit and a ranging device as described in any one of claims 1-9; The three-dimensional imaging unit is used to generate three-dimensional imaging information of the target object based on the distance information corresponding to each wavelength channel and the scanning angle.

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